Dissertations / Theses: 'Geological engineering'

1

Tsidzi, K. E. N. "The engineering geological characteristics of foliated rocks." Thesis, University of Newcastle upon Tyne, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356161.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Brink, George Eksteen. "Engineering geological evaluation of transported tropical red soils." Thesis, University of Pretoria, 2015. http://hdl.handle.net/2263/53557.

Full text

Abstract:

Tropical soils include a wide variety of pedogenic materials common to the tropical regions of the world, of which the material properties and engineering behaviour may vary significantly. These soils in many ways have unique characteristics that can mainly be ascribed to the compositions and micro-structures of a material developed under hot, wet soil-forming conditions. Due to the variation in their properties and behaviour, the classification of soils formed under such conditions as distinct and well-defined soil types appears to have been avoided in the past. Unfortunately, this has brought about the grouping and classification of materials of significantly varying chemical, geological and/or geotechnical properties and engineering behaviour under a single, all-encompassing term of tropical red soils . The unique pedogenic environment and soil characteristics further mean that conventional soil mechanics concepts and geotechnical investigative procedures, developed almost exclusively from work completed on temperate soils, do not necessarily apply to soils formed in tropical environments. This research reviews the typical and unique characteristics and behaviour of tropical red soils as summarised in the existing literature, including the application of existing soil classification systems and the possible ambiguity existing in the classification and nomenclature pertaining to soils formed in tropical environments. Significant inconsistencies in the identification and classification of tropical red soils and laterites were observed to exist throughout the available literature, with frequently overlapping ranges of geological, geotechnical and chemical properties reported for both lateritic and tropical red soil types. Much has been written in the existing literature regarding the unique material characteristics and engineering behaviour of tropical red soils and the inapplicability of conventional soil mechanics concepts. The majority of the available results, conclusions and recommendations in the existing literature refer to residual tropical red soils only, with very little information regarding the characteristics and behaviour of transported tropical red soils being reported. The characteristics and behaviour of a number of transported tropical red soil horizons, from a selected area in the Mayoko region of the Republic of the Congo, were evaluated through conventional and specialised testing regimes during the completion of this study. A large number of disturbed and undisturbed samples were collected from the study area and submitted to geotechnical laboratories in South Africa to establish the chemical-, mineralogical-, index and mechanical properties of these soils. The test results, sample preparation and test procedures and effect of these on the engineering behaviour of the material were evaluated and compared to the typical results reported for residual tropical red soils in the literature. A number of the findings from this study, particularly the sensitivity of tropical red soils to change in moisture content and effect of the dispersing agent on the reported particle size distribution of such soils, confirmed the findings which have been reported in the literature for residual tropical red soils. However, the transported tropical red soils were also found to differ markedly from residual tropical red soils in certain aspects, most notably in terms of the apparent effect of the lack of remnant structure on the material mechanical properties, permeability, sample disturbance and relevance of tests completed on remoulded test specimens. Thesis (PhD)--University of Pretoria, 2015. Geology PhD Unrestricted

APA, Harvard, Vancouver, ISO, and other styles

3

Watts, C. R. "Engineering geological roading aggregate investigations of the Wakatipu Basin." Thesis, University of Canterbury. Engineering Geology, 1988. http://hdl.handle.net/10092/10395.

Full text

Abstract:

The Wakatipu Basin lies within the Otago Schist belt, and aggregates derived from the schist do not meet New Zealand basecourse specifications. This study comprises engineering geological investigations of the roading aggregate with the objective of identifying potential aggregate source areas which comply with specifications. Five aggregate sources, two glacial and three post-glacial, have been identified, and their geology related to aggregate quality. A survey of existing aggregate quarries confirmed the sub-specification quality of schist derived roading aggregate, and that the highest quality roading aggregate of the Basin is produced from exotic glacial transported graywacke. A graywacke rich aggregate source area of Kame terraces was investigated. Investigations included mapping at scales of 1:10 000 and 1:1 500, and the excavation of test pits. A geotechnical testing programme concluded that the Kame terrace source area was capable of producing roading aggregate for basecourse, and is comparable with the highest quality roading aggregate of the Wakatipu Basin. Subsequently, the Queenstown - Lakes District Council has developed an aggregate quarry within the Kame terrace source area.

APA, Harvard, Vancouver, ISO, and other styles

4

Wang, Bujin. "Well site selection algorithm considering geological, economical and engineering constraints." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ60512.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

5

Mukhtar, Jonathan-Adam. "Engineering Geological and Geotechnical Characterisation of Selected Port Hills Lavas." Thesis, University of Canterbury. Geological Sciences, 2014. http://hdl.handle.net/10092/9971.

Full text

Abstract:

This thesis aims to create a specific and robust geotechnical data set for the Lyttelton Volcanic Group, and investigate the effect of emplacement and post-emplacement mechanisms on geotechnical characteristics. The thesis provides an engineering geological model of a representative section of the Lyttelton Volcanic Complex, which, in conjunction with field observations, informed the subdivision of the main lithological groups into geotechnical sub-units. The sub-units account for the geological variations within the rock types of this study. Eighteen geotechnical sub-units were identified, sampled and characterised: 1trachytic dykes, 2trachytic domes, 3trachytic lava, 4brecciated basaltic ignimbrite, 5moderately welded basaltic ignimbrite, 6highly welded basaltic ignimbrite, 7red ash, 8crystal dominated tuff, 9lithic dominated tuff, 10rubbly basaltic breccia, 11unweathered basaltic lava, 12slightly to moderately weathered basaltic lava, 13highly to completely weathered basaltic lava, 14highly vesicular basaltic lava bomb, 15basaltic dyke, 16blocky basaltic lava, 17volcanogenic conglomerate and 18volcanogenic tuffaceous sandstone. Thirteen units were able geotechnically tested. Sample preparation and geotechnical testing followed ASTM and ISRM guidelines respectively. Geotechnical testing included: uniaxial compressive strength (σci), point load strength index (Is(50)), porosity (n), density (ρd), P and S wave velocities (Vp and Vs), slake durability (Id2), Young’s Modulus (E), Poisson’s Ratio (υ), shear modulus (G) and bulk modulus (K). The igneous lithologies included in this study have been characterised using the Detailed Engineering Geological Igneous Descriptive Scheme, developed purposely for the needs of the thesis. The results of laboratory testing showed many strong trends with geological characteristics and relationships between geotechnical parameters. Parameters such as porosity, density, P-wave velocities, Young’s Modulus and point load strength showed very strong correlations with uniaxial compressive strength. Variability in the physical and mechanical properties is attributed to the geological factors, which dictate the material behaviour. These include texture, grain size, composition, welding, lithification, flow banding, percentage and size of phenocrysts/clasts/lithics. Geological factors affecting geotechnical behaviour are a function of emplacement mechanism. Four distinct emplacement mechanisms were identified in this study: lava flows, pyroclastic density currents, intrusions (dykes) and airfall deposits. Typically, lava flows and intrusions have higher strength, durability, density and lower porosity than pyroclastics and airfall deposits. Importantly, the data illustrates a considerable variability in some geotechnical parameters within the same unit (e.g. 58-193 MPa strength variation in the unweathered basaltic lava). Variability within rocks with similar emplacement mechanisms is attributed to the effects of post-emplacement mechanisms and processes (e.g. weathering, alteration and micro/macro fracturing leading to lower strength). Evaluation of engineering geological and geotechnical parameters of rock and soil materials are required for engineering purposes, specifically when any form of design is required. This study has highlighted the importance and necessity to identify volcanic lithologies and features correctly as there are consequences for geotechnical behaviour, and that volcanic data from literature data should not be used without the correct degree of ground-truthing and geological context. Location-specific engineering geological data are necessary for the quantitation of variability in engineering geological characterisation for engineering geological models, designs and simulations in the Port Hills Volcanics.

APA, Harvard, Vancouver, ISO, and other styles

6

Fersoy, Cagla. "Engineering Geological Characterization Of The Tuffite Member Of Hanc&amp." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12610247/index.pdf.

Full text

Abstract:

Along NS trending road cut between &Ccedil ayyolu and incek, relatively thick tuffite layer of the Han&ccedil ili formation has been exposed. It is alternating with other lacustrine deposits such as clayey limestone, marl, siltstone and mudstone. These units unconformably overlie the Mesozoic basement limestones of Akbayir formation. The illite rich tuffite consists of glass shards tridymite, biotite, quartz and plagioclase. It has a persistent areal extend and forms the foundation of the residential buildings at several localities. In this thesis, it is aimed to assess the engineering geological properties of the tuffite layer and to investigate its suitability as a foundation material. In order to accomplish this task, field studies and laboratory tests were conducted. Field studies involve detailed site geological observation. Laboratory studies include tests to investigate mechanical, physical and mineralogical properties of the tuffite. v Analyses revealed very weak nature of tuffite with strength values ranging between 0.1 MPa and 1.00 MPa. The tuffite is characterized with very high effective porosity (43.3%) and very low dry and saturated densities (1.19 Mg/m3 and 1.62 Mg/m3, respectively). The slake-durability tests yield medium durability. The durability index of tuffite is rated as very poor. Considering index properties and the durability assessment it is concluded that tuffite serves as a poor foundation material.

APA, Harvard, Vancouver, ISO, and other styles

7

Strang, Daniel Rodney. "Engineering Geological Characterisation and Slope Stability Assessment of Whitehall Quarry, Waikato." Thesis, University of Canterbury. Geological Sciences, 2010. http://hdl.handle.net/10092/5617.

Full text

Abstract:

Whitehall Quarry is located 4 km east of Karapiro, near Cambridge within the Waikato District. Current quarrying operations produce between 150,000 and 300,000 tonnes of aggregate for use in the surrounding region. This study is an investigation into the engineering geological model for the quarry and pit slope stability assessment. Pit slope stability is an integral aspect of quarrying and open-pit mining since slopes should be as steep as possible to minimise waste material which needs to be removed, yet shallow enough to minimise potential hazards to personnel and equipment below pit slopes. This study also assesses the stability of complex wedge located within the north western corner of the quarry. Initial estimates approximate a wedge mass volume of 500,000 m3; failure was triggered during the late 80‟s due a stripping programme at the head of the mass. Field and laboratory investigations were carried out to identify and quantify engineering geological parameters. Photogrammetric and conventional scanline analytical techniques identified two domains within the quarry divided by the Main Quarry Shear Zone (MQSZ). Discontinuity orientations are the key differences between the two domains. Bedding planes appear to have slightly different orientations and each domain has very different joint sets identified. Point load, shear box, ring shear testing approximated intact rock strength, shear strength and fault gouge behaviour properties. The main geological units at the quarry are greywacke sandstone interbedded with argillaceous mudstone. Uniaxial compressive strength estimates approximated the intact rock strength for sandstone to be between 30 and 230 MPa depending on weathering grade, while the strength of mudstone was approximated at 5 MPa. Residual shear strength was carried out to estimate the approximate effective angle of internal friction for both a smooth UW-SW sandstone joint and a mudstone bedding plane, these being 37o and 34o respectively. Laboratory testing on fault gouge indicated an approximate angle of internal friction of 13o and the presence of kaolinte and montmorillonite was identified. Pit slope stability analysis utilised the Markland test for identification of potential failures within slopes. Wedge failures are the most common potential failure type, then planar failures along bedding planes. Potential failures are most likely to be less than 10 m3 due to the high fracture frequency and low persistence of common joint sets. However, larger failures in the order of 100 m3 are possible along fault and bedding planes where persistence is typically greater than 20 m. Kinematic analysis of the Northern Wedge Failure estimated a mean factor of safety of 0.97. Currently the wedge is assessed as marginally unstable. Electronic distance measurement over 11 months recorded an approximate mean wedge velocity of 19 mm/month. Sensitivity analysis identified pore water pressure as a key parameter. De-watering the wedge via a series of inclined drainage holes appears to be the best mitigation method. However, the mine and monitor approach is also acceptable but with anticipated risk to personnel and equipment. Monitoring instrumentation such as a wireline and crack-meters should be implemented.

APA, Harvard, Vancouver, ISO, and other styles

8

Narbett, Robert Wyn. "Geological and engineering properties of estuarine alluvium from the Severn Estuary." Thesis, University of Bristol, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243694.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Sadagah, Bahaaeldin Hashim. "Engineering geological maps for road design & construction in Saudi Arabia." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47636.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Francis, Helen. "Orebody complexity in geological control over selective mining." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=20204.

Full text

Abstract:

This thesis proposes a morphological complexity index for use in classifying orebodies. Formulated and tailored for application on underground steep clipping narrow base metal orebodies from Inco Limited's Manitoba Division, the complexity index was proved transferable to the base metal deposits of Inco Limited's Ontario Division. Thus it appears that the index could be applied to various styles of mineralization and orebody morphology. The complexity classification was designed to aid in geologic control and subsequently improve mining method performance. Motivated by an industry wide move from selective mining to bulk mining, to increase productivity and improve safety. It is intended that development and application of an orebody complexity index will increase the understanding of geology and prevent the sacrifice of selectivity, minimizing dilution and ore loss. With the advent of automation, simplification in mining is necessary and thus more intelligent design and control vital. This thesis offers one means by which MDPPC (Mine Design, Planning and Production Control) could be further integrated with geological understanding to achieve such an end. The thesis provides explanation of how such a complexity index can be used to understand mining method performance and be used for more successful mine design.

APA, Harvard, Vancouver, ISO, and other styles

11

Haidari, Arman S. "Statistical approaches to leak detection for geological sequestration." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/65758.

Full text

Abstract:

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, June 2011. "April 2011." Cataloged from PDF version of thesis. Includes bibliographical references (p. 181-189). Geological sequestration has been proposed as a way to remove CO₂ from the atmosphere by injecting it into deep saline aquifers. Detecting leaks to the atmosphere will be important for ensuring safety and effectiveness of storage. However, a standard set of tools for monitoring does not yet exist. The basic problem for leak detection - and eventually for the inverse problem of determining where and how big a leak is given measurements - is to detect shifts in the mean of atmospheric CO₂ data. Because the data are uncertain, statistical approaches are necessary. The traditional way to detect a shift would be to apply a hypothesis test, such as Z- or t-tests, directly to the data. These methods implicitly assume the data are Gaussian and independent. Analysis of atmospheric CO 2 data suggests these assumptions are often poor. The data are characterized by a high degree of variability, are non-Gaussian, and exhibit obvious systematic trends. Simple Z- or t-tests will lead to higher false positive rates than desired by the operator. Therefore Bayesian methods and methods for handling autocorrelation will be needed to control false positives. A model-based framework for shift detection is introduced that is capable of coping with non-Gaussian data and autocorrelation. Given baseline data, the framework estimates parameters and chooses the best model. When new data arrive, they are compared to forecasts of the baseline model and testing is performed to determine if a shift is present. The key questions are, how to estimate parameters? Which model to use for detrending? And how to test for shifts? The framework is applied to atmospheric CO₂ data from three existing monitoring sites: Mauna Loa Observatory in Hawaii, Harvard Forest in central Massachusetts, and a site from the Salt Lake CO₂ Network in Utah. These sites have been chosen to represent a spectrum of possible monitoring scenarios. The data exhibit obvious trends, including interannual growth and seasonal cycles. Several physical models are proposed for capturing interannual and seasonal trends in atmospheric CO₂ data. The simplest model correlates increases in atmospheric CO₂ with global annual emissions of CO₂ from fossil fuel combustion. Solar radiation and leaf area index models are proposed as alternative ways to explain seasonality in the data. Quantitative normality tests reject normality of the CO₂ data and the seasonal models proposed are nonlinear. A simple reaction kinetics example demonstrates that nonlinearity in the detrending model can lead to non-Gaussian posterior distributions. Therefore Bayesian methods estimation will be necessary. Here, nonlinear least squares is used to reduce computational effort. A Bayesian method of model selection called the deviance information criterion (DIC) is introduced as a way to avoid overfitting. DIC is used to choose between the proposed models and it is determined that a model using a straight line to represent emissions driven growth, the solar radiation model and a 6-month harmonic term does the best job of explaining the data. Improving the model is shown to have two important consequences: reduced variability in the residuals and reduced autocorrelation. (cont.) Variability in the residuals translates into uncertainty in CO₂ forecasts. Thus by reducing the spread of the residuals, improving the model increases the signal to noise ratio and improves the ability to detect shifts. A least squares example using CO₂ data from Mauna Loa is used to illustrate the effect of autocorrelation due to systematic seasonal variability on the ability to detect. The issue is that ordinary least squares tends to underestimate uncertainty when data are serially correlated, implying high false positive rates. Improving the model reduces autocorrelation in the residuals by eliminating systematic trends. Because the data exhibit gaps, Lomb periodograms are used to test the residuals for systematic signals. The model chosen by DIC removes all of the growing and seasonal trends originally present at the 5% level of significance. Thus improving the model is a way to reduce autocorrelation effects on false positives. A key issue for future monitoring sites will be demonstrating the ability to detect shifts in the absence of leaks. The urban weekend weekday effect on atmospheric CO₂ is introduced to illustrate how this might happen. A seasonal detrending model is used to remove systematic trends in data at Mauna Loa, Harvard Forest and Salt Lake. Residuals indicate the presence of positive shifts at the latter sites, as expected, with the magnitude of the shift being larger at the urban site than the rural one (~ 8 ppm versus ~ 1 ppm). Normality tests indicate the residuals are non-Gaussian, so a Bayesian method based on Bayes factors is proposed for determining the amount of data needed to detect shifts in non-Gaussian data. The method is demonstrated on the Harvard and Salt Lake CO₂ data. Results obtained are sensitive to the form of the error distribution. Empirical distributions should be used to avoid false positives. The weekend weekday shift in CO₂ is detectable in 48-120 samples at the urban site. More samples are required at the rural one. Finally, back-of-the-envelope calculations suggest the weekend weekday shift in emissions detected in Salt Lake is - 0(0.01) MtCO₂km- yr- 1. This is the equivalent of 1% of 1 MtCO₂ stored belowground leaking over an area of 1 km2 The framework developed in this thesis can be used to detect shifts in atmospheric CO₂ (or other types of) data after data is already available. Further research is needed to address questions about what data to collect. For example, what sensors should be used, where should they be located, and how frequently should they be sampled? Optimal monitoring network design at a given location will require balancing the need to gather more information (for example, by adding sensors) against operational constraints including cost, safety, and regulatory requirements. by Arman S. Haidari. Ph.D.

APA, Harvard, Vancouver, ISO, and other styles

12

Wezenberg, Udo. "An engineering geological investigation of batter stability, Weavers opencast coal mine, Huntly." Thesis, University of Canterbury. Geology, 1988. http://hdl.handle.net/10092/9397.

Full text

Abstract:

Cut slope batter instability of overburden in Weavers Opencast Mine at Huntly involves 0-65m succession of Waikato Coal Measures and Glen Afton Claystone of the Te Kuiti Group (Eocene to Oligocene), and a 15-65m sequence of overlying gravels, pumiceous sands, silts, clays and peats of the Tauranga Group (Pliocene to Holocene). Field and laboratory investigations were conducted to determine the causes and mechanisms of cut batter instability. Field investigations included: detailed engineering geological mapping of the entire highwall at a scale of 1:1584; detailed batter logging and sampling of lower Tauranga Group materials and defect orientation surveys of Te Kuiti Group and Tauranga Group for stereographic analysis of failure modes. Laboratory investigations included: shear strength testing of the Te Kuiti-Tauranga Group unconformity contact and representative joint and bedding planes in the lower Tauranga Group; X.R.D. and chemical tests for clay mineralogy, grainsize distribution, atterberg limits, field moisture content, density and void ratio determination for Tauranga Group Materials.

APA, Harvard, Vancouver, ISO, and other styles

13

Ho, Chiu-shek. "Stereographic projection and mapping of engineering geology case study near Jordan Valley, Hong Kong /." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B38848673.

Full text

APA, Harvard, Vancouver, ISO, and other styles

14

Sizer, Calvin Gregory. "Minor actinide waste disposal in deep geological boreholes." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/41595.

Full text

Abstract:

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2006. Includes bibliographical references (leaves 63-65). The purpose of this investigation was to evaluate a waste canister design suitable for the disposal of vitrified minor actinide waste in deep geological boreholes using conventional oil/gas/geothermal drilling technology. The nature of minor actinide waste was considered, paying particular attention to nuclides whose decay energy and half lives were of relative significance to the minor actinide waste as a whole. Thermal Analysis was performed based on a reference borehole design, by Ian C. Hoag. The strategy of the thermal analysis is aimed at finding peak temperatures within the configuration, paying particular attention to the heat transfer under deep geological conditions in the air gap between the canister and the borehole. A first order economic analysis was made to compare the designed canister emplacement costs to that of intact spent fuel. The results of this analysis show that three minor actinide nuclides dominate heat generation after ten years cooling: Cm-244, Am-241, and Am-243 account for 97.5% of minor actinide decay heat. These three nuclides plus Np-237 account for 99% of the minor actinide mass. The thermal analysis was based on an irretrievable canister design, consisting of a 5 meter long synroc waste form, with minor actinides loaded to 1% wt, an outer radius of 15.8 cm and inner annular radius of 8.5 cm. Filling the annulus with a vitrified technetium and iodine waste form was found to be feasible using a multi-stage emplacement process. This process would only be required for three of the fifty boreholes because technetium and iodine have low heat generations after 10 years cooling. The suggested borehole waste form has a maximum centerline temperature of 349C. The costs of drilling boreholes to meet the demand of 100,000MT of PWR waste are estimated to be 3.5% of the current nuclear waste fund, or about $9.6/kg of original spent fuel. by Calvin Gregory Sizer. S.B.

APA, Harvard, Vancouver, ISO, and other styles

15

Lawrence, Ursula. "The engineering geology of the clay-with-flints : (as shown on the British Geological Survey 1:50 000 New Series Geological sheets)." Thesis, University of Surrey, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420056.

Full text

APA, Harvard, Vancouver, ISO, and other styles

16

Archer, James William. "Pressure stimulated voltage detection in manmade and geological materials." Thesis, University of Sussex, 2017. http://sro.sussex.ac.uk/id/eprint/71818/.

Full text

Abstract:

This thesis investigates pressure stimulated voltages (PSVs) in manmade and geological materials using a field capable and commercially viable electric potential sensor (EPS) technology. Sensing technologies are of great importance for the structural health monitoring (SHM) of manmade and geological structures and are critical for improving the health and safety of humans and infrastructure. A wide variety of sensing technologies are needed to assess damage over structures. Work by others involves measuring pressure stimulated electrical emissions (PSEs) (i.e. the study of pressure stimulated voltage, electric field and current) that are related to acoustic emissions (AEs) in rock and cement mortar, and also mechanical properties. Although these studies yield promising results, the measurement tools (laboratory electrometers and electromagnetic emissions (EME) antennas) are not suitable for field use. This is predominantly because of the need of Faraday shielding to reduce noise, plus the impracticalities and high costs associated with using laboratory instruments for SHM. However, the EPS developed at the University of Sussex is capable of measuring PSVs in rocks and is field capable. In this thesis, PSVs in rocks and man-made materials were measured using two EPS variants. An existing capacitively coupled sensor was used to measure high frequency (25.5 mHz to 750 kHz) transient PSVs associated with cracking. In addition, a novel directly coupled smart EPS was developed for monitoring low frequency (DC to 250 Hz) PSVs associated with applied stress. A signal conditioning and data reduction procedure was developed for PSV emissions analogous to methods used for AE. A new robust method for measuring PSV was established in which cylindrical material specimens were instrumented with strain gauges, piezo transducers and EPSs to measure strain, AE and PSV respectively and a force transducer was used to measure the applied load. The results showed that PSVs were detected in a wide range of piezo and non-piezo rocks and for the first time in concrete, in the range of millivolts (0.32 mV – 1180 mV). Faraday shielding the experiments was not necessary as with other PSE monitoring technologies. For oven dried materials there was some degree of correlation between PSV high frequency transient signals and AE (i.e. cracking). Rocks had cross-correlation coefficients ranging from 0.13 to 0.86, and the cross-correlation coefficient for concrete (0.24) was lower than most rock lithologies. Environmental conditions and the stage of uniaxial deformation of materials influence PSV-AE cross-correlations. Water or saline saturation of materials generally reduced the PSV-AE cross correlation coefficients. During the cyclic loading of various rock lithology, a work hardening effect was observed in the PSV emissions analogous to the well-known Kaiser and Felicity effect of AE. A likely reason for the PSV-AE correlations is that PSVs are generated by the movement and separation of fresh charged fracture surfaces. EPS could be a cost effective and more advanced technology for detecting cracking in structures and in combination with piezo transducers, could be used to identify material deformation stages. There was a linear relationship between applied stress and DC/low frequency PSV in piezo rocks (r2 = 0.84) but not non-piezo rocks (r2 = 0.0063). The piezoelectric effect of quartz is the most likely generation mechanism behind the PSV-stress relationship. The novel, directly coupled, smart EPS is a successful design as it has the necessary high input impedance and low noise characteristics for measuring PSVs noninvasively at low frequencies. EPS could be the first non-invasive technology for in-situ stress measurement in quartz bearing rocks; current methods involve disturbing the rock mass and are expensive to implement. In conclusion, the results show that the EPS-PSV measurement technique is viable for the SHM of rocks and concrete. Although, factors such as material composition, environmental condition and type of material deformation influence PSV characteristics and would need to be accounted for in real world applications. Future directions for the research would involve the development of a “real time” PSV event detection system for long term monitoring of structures for SHM applications. Additionally, large scale testing of different material samples in different environmental conditions and the testing of larger structures using arrays of EPS would be necessary before commercialisation. Future commercialisation could result in a restively coupled broadband monolithic semiconductor EPS being developed for SHM to monitor PSVs associated with applied stress and cracking events simultaneously. This would produce a more cost effective and advanced tool than existing technologies, such as piezo transducers for monitoring AE and in-situ stress monitoring techniques.

APA, Harvard, Vancouver, ISO, and other styles

17

Panthi, Krishna Kanta. "Analysis of Engineering Geological Uncertainties Related to Tunnelling in Himalayan Rock Mass Conditions." Doctoral thesis, Norwegian University of Science and Technology, Department of Geology and Mineral Resources Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-711.

Full text

Abstract:

The need for tunnelling in Nepal, as in the Himalayan region in general, is enormous, particularly for hydropower development. Due to active tectonic movement and dynamic monsoon, the rock mass in the Himalaya is relatively weak and highly deformed, schistose, weathered and altered. Predicting rock mass quality, analyzing stress induced problems, in particular tunnel squeezing, and predicting inflow and leakage often have been found extremely difficult during planning stage. Considerable discrepancies have been found between predicted and actual rock mass conditions, resulting in significant cost and time overrun for most of the tunnelling projects. Finding innovative solutions for quantifying geological uncertainties and assessing risk are therefore key factors for cost effective and optimum future tunnelling through Himalayan rock mass.In this thesis, a probabilistic approach of uncertainty analyses has been introduced to deal with the most important geological uncertainties reflecting Himalayan rock mass conditions. A geological uncertainty analysis model concept based on the software program @Risk has been applied for this purpose.The analyses presented in this thesis are based mainly on four headrace tunnel cases from Nepal; 1) 60 MW Khimti I hydropower project, 2) 144 MW Kaligandaki “A” hydroelectric project, 3) 14 MW Modi Khola hydroelectric project, and 4) 69 MW Middle Marsyangdi hydroelectric project. The first three projects have been completed recently and the fourth one is under construction.The thesis identifies the most crucial aspects of tunnel stability problems (geological uncertainties) by reviewing the engineering geological conditions of the respective cases and the Himalayan geology. It also evaluates the theoretical aspects of the main factors influencing on tunnel stability, reviews the engineering geological conditions, the extent of pre-construction phase engineering geological investigations, evaluates the deviation between predicted and actual rock mass conditions, and describes the laboratory testing that has been carried out for the respective cases. Probabilistic approaches that have been applied in the field of engineering geology in past and the basic theory on statistical analyses are briefly discussed. Main emphasis is then placed on the descriptions of useful probability distribution functions (pdf), the @Risk statistical analysis tool, the applied uncertainty analysis model concept and @Risk analysis for the respective tunnel cases.The uncertainty analyses include rock mass quality evaluation based on the Q-system of rock mass classification for Khimti and Modi Khola headrace tunnels, tunnel squeezing based on Hoek and Marinos approach for Kaligandaki and Middle Marsyangdi headrace tunnels, and finally analysis of water leakage from the Khimti headrace tunnel. The degree of correlation between simulated results achieved by the @Risk model and values actually measured in the tunnel is discussed and the sensitiveness and effect of variations in the value of each input parameter and sensitivity of equations and methods used to analyze geological uncertainties are evaluated.It is concluded that the proposed uncertainty analysis approach gives very promising results and has a great potential for analyzing tunnel projects in the Himalayan rock mass conditions, but more cases are needed for conforming the reliability of the methodology.

APA, Harvard, Vancouver, ISO, and other styles

18

Kelsey, Philip Ian. "An engineering geological investigation of ground subsidence above the Huntly East Mine area." Thesis, University of Canterbury. Geological Sciences, 1986. http://hdl.handle.net/10092/1659.

Full text

Abstract:

Ground subsidence above the Huntly East Mine at the N.Z.E.D. Hostel has affected an area of approximately seven hectares with measured settlements of over 8OOmm. Extensive damage was suffered by most buildings and services of the hostel complex (a $2M development) with remedial measures being estimated at approximately $450,000. To determine the cause(s) and mechanism(s) of the subsidence, site and laboratory investigations were undertaken. Site investigations included core and wash drilling, geophysical borehole logging, dutch cone penetrometer soundings plus piezometer installation and minotoring. Laboratory investigations included one dimensional consolidation and permeability testing, SEM fabric studies, XRD and chemical tests for clay mineralogy, and determinations of Atterberg Limits and grain size distributions. The mine overburden geology at the site consists of a 35 to 60m thick sequence of mudstones and coal seams of the Te Kuiti Group (Eocene to Oligocene), and overlain by a 50 to 70m thick succession of saturated sands, silts and gravels of the Tauranga Group (Pliocene to Holocene). Within the Tauranga Group three aquifers are present. Drilling, combined with laboratory testing has defined a 4 to 10 metre thick, laterally extensive, highly compressible ignimbritic silt aquitard above the lowest aquifer. The engineering geological model considered most likely to explain the subsidence is mine roof collapse causing void migration to near the top of the Te Kuiti Group sequence resulting in drainage and depressurising of aquifers at the base of the Tauranga Group. Aquifer depressurisation is considered likely to cause consolidation within both the aquifer and aquitards associated with it. Back-analyses of the dewatering consolidation model in terms of both magnitude and rates of settlement are consistent with observed values. A finite difference numerical analysis was developed for estimations of settlement rates. Further field verification of the dewatering consolidation model requires monitoring of piezometers in areas of potential ground movement and inspection of workings under subsided ground.

APA, Harvard, Vancouver, ISO, and other styles

19

Jeremias, Filipe Telmo Santos Alcobia Alves. "Geological controls on the engineering properties of mudrocks of the North Lisbon area." Thesis, University of Sheffield, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.700953.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

LaPorte, David. "Evaluating Landslide Risk Management in Guatemala City through a Study of Risk Perception and Behavior Changes." Thesis, Colorado School of Mines, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10816996.

Full text

Abstract:

In October of 2015, a devastating landslide killed an estimated 350 people in the community of El Cambray II, located in a Guatemala City ravine, highlighting the need to manage landslide risk in precarious urban settlements in the area. This project evaluates landslide risk management in the Guatemala City metropolitan area to better encourage at-risk community members to change behaviors to reduce landslide risk. To evaluate specific risk management initiatives, the authors tracked changes in community members’ risk perception, knowledge and behaviors by surveying communities at different points in time during the implementation of initiatives. Using these factors as metrics, we demonstrate the degree to which these factors will change when a community-based risk management initiative is implemented in a precarious settlement. To characterize landslide risk perceptions, perception of landslide risk was compared to perception of other societal risks to which community members are exposed, and a rubric of relative knowledge of landslide risk was developed. A preliminary F-N (frequency of events vs number of fatalities) plot quantifies the degree of societal acceptance of landslide risk. Landslide risk faced by settlement residents was estimated with a preliminary landslide event database, for comparison to a quantified perception of risk to understand if communities perceive risk accurately, and to identify the level of intervention that would encourage behavioral change. Perceptions and knowledge of landslide risk are not being significantly changed by the studied initiatives, but behaviors are modestly changing, particularly for community members directly involved with the implementing organization. The results of this study are being shared with risk managers to improve their selection of initiatives, and to empower at-risk communities by incorporating their knowledge and perception of risk into risk management strategies.

APA, Harvard, Vancouver, ISO, and other styles

21

Silverman, Joseph B. "Source distribution analysis of magnetic microscopy maps of geological samples." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/59915.

Full text

Abstract:

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010. Cataloged from PDF version of thesis. Includes bibliographical references (p. 52-53). Superconducting quantum interference devices (SQUID) are currently the most sensitive magnetometers for geological samples. Standard SQUID magnetometers are able to directly estimate the net moment of a sample, while SQUID microscopes require complex inversion of maps of the magnetic field above the sample. In order to extract magnetization information from SQUID microscope measurements, it is customary to model the sample as a distribution of magnetic dipoles. The calculations required for this operation in the space domain typically involve a pseudo inversion which becomes problematic due to the large amount of data, measurement noise, inherent loss of information in computational discretization, and ambiguity in determining an optimized "best" solution. To ameliorate these problems, we have implemented several regularization techniques and constraints. Using synthetic, computationally generated measurements, our investigation demonstrates that Tikhonov regularization with a high pass filter matrix performs better than unregularized least square methods, truncated singular value decomposition, and Tikhonov regularization using an identity matrix (minimum norm). Our study also gives insight regarding the benefit and cost of setting various constraints. Our findings are then tested on real measurements of a sample of shocked basalt and a test sample comprised of a section of a refrigerator magnet. by Joseph B. Silverman. S.B.

APA, Harvard, Vancouver, ISO, and other styles

22

Lattin, Matthew M. "California glacial till and the glaciated valley landsystem| Engineering classification and properties." Thesis, San Jose State University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1552263.

Full text

Abstract:

The engineering characteristics of glacial tills in the Sierra Nevada are difficult to determine due to the depositional nature of the material; however, testing methods unique to these dense materials can be utilized to obtain good engineering data. A literature review was conducted to determine testing methods and recommendations for engineering in glacial till. Further literature review revealed a significant amount of glacial deposits mapped by the USGS and CGS in the Sierra Nevada geomorphic province in California. Sierra Nevada glacial till field and lab data were obtained from Taber Consultants along with samples for further testing. Consequently, four significant conclusions were determined from testing and research. First, it was determined that Sierra Nevada glacial deposits may have large amounts of clay due to neoformation of the local volcanic rockform. As a result, plasticity and compressibility results ranged from low to high. Second, SPT N values for matrix material were correlated with depth. Third, unconfined compressive strength results for coarse-grained samples with no cohesive binding were independent of depth. Fourth, the matrix material dominated the engineering behavior of a given glacial till layer.

APA, Harvard, Vancouver, ISO, and other styles

23

Ikard, Scott. "Geoelectric monitoring of seepage in porous media with engineering applications to earthen dams." Thesis, Colorado School of Mines, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3602502.

Full text

Abstract:

A monitoring methodology is developed for investigating seepage and internal erosion in earthen dams with time-lapse measurements of self-potential anomalies associated with conservative salt and non-conservative heat tracer migration in the subsurface. The method allows for 1) detecting seepage zones in earthen dams and determining the preferential flow paths through seepage zones in a non-invasive manner from the ground surface, 2) monitoring the transient evolution of seepage path geometry, flow velocity, and permeability in real-time if high frequency measurements can be made, and 3) long-term non-invasive monitoring with wired or wireless sensors The method is first theoretically developed and tested in a laboratory using a conservative tracer, and then demonstrated at a 12 m high, 100 m long leaking earthen dam with complex, unknown seepage paths. The method is shown to be capable of rapidly detecting seepage zones discovered during a reconnaissance survey, and delineates the predominant seepage directions through the dam from the time-lapse self-potential anomalies. The time-lapse monitoring approach ensures improved spatial resolution, increased measurement frequencies, and improved data analysis capabilities relative to traditional approaches to seepage detection, and a cost-reduction for the application of this methodology is anticipated to follow advancements in wireless sensing and monitoring technologies. This method is designed to be a more cost-effective means of interrogating earthen dams and levees to answer questions such as: Is the dam safe? What are the geometries of the seepage zones inside of the dam, and over what spatial scale does anomalous seepage occur? What are preferential paths through the seepage zones? Is internal erosion actively occurring? At what rates are the geometries, permeabilities and flow rates of preferential seepage paths evolving?

APA, Harvard, Vancouver, ISO, and other styles

24

Faber, Ethan J. "Development of a landslide risk rating system for small-scale landslides affecting settlements in Guatemala City." Thesis, Colorado School of Mines, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10014960.

Full text

Abstract:

Many settlements in the Guatemala City Metropolitan Area (GCMA) face significant possibilities of fatalities due to their location in steep ravines that are subjected to periodic large-scale landslides. Since the housing in the at-risk areas is relatively low-cost, it is typically cost-prohibitive to mitigate the risk to an acceptable level. Thus, permanent relocation is the only truly viable option to ensure the long-term safety of everyone. However, there are several economic and social obstacles impeding successful implementation of a relocation program. Still, there are many other landslide risk reduction techniques (such as retaining walls, community drainage systems, and alert systems) implemented by government organizations and non-profit groups. These techniques are helpful in landslide risk reduction (LRR), but residents are only partially involved in the entire process. Therefore, increasing residents’ education and ability to better understand their level of landslide risk will help with LRR. Residents can integrate and collaborate with the government organizations and non-profits implementing mitigation techniques and of even greater benefits, the education and ability for residents to understand their landslide risk can provide additional avenues for LRR not otherwise achievable. The purpose of this research is to develop a landslide-risk-rating-system (LRRS) that can be used by trained residents to better understand their risk (similar to other landslide or rockfall hazard-rating systems commonly used by department of transportation organizations). The focus of this LRRS is only on small-scale landslides (typically the size of a house or less) because evaluating the risk of large-scale landslides is too complicated to be done by trained non-technical experts. The LRRS asks questions related to landslide risk that can be used to calculate a landslide risk score to indicate the relative level of risk. The LRRS was created by reviewing published literature documenting other landslide rating systems and incorporating similar factors correlated with landslide risk. Then, forty sites were visited in the GCMA to inventory the factors at houses that are vulnerable to landslides in order to evaluate which factors were most useful for predicting the relative risk. The predicted risk scores were compared to ranked risk scores estimated by the author to ensure the results were valid. Statistical analysis identified which of these factors best-predicted landslide risk. These factors include slope angle, slope height, strength of slope material or material type, aperture of cracks, spatial impact, largest probable landslide volume, largest probable percentage of the living area that could be impacted from a landslide, and total person-hours a living area is occupied per day. Future work should focus on the transformation of the tool into a more user-friendly format for use by residents, the implementation process, and monitoring plan.

APA, Harvard, Vancouver, ISO, and other styles

25

Nguyen, Thanh Son. "Computational modelling of thermal-hydrological-mechanical processes in geological media." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=29096.

Full text

Abstract:

There are a number of engineering situations where fluid-saturated geological media can be subjected to thermal effects. These include the disposal of heat-emitting nuclear fuel wastes in saturated geological formations, extraction of energy resources such as oil and natural gas by steam injection and the recovery of geothermal energy by ground source heat exchangers. The objective of this thesis is to study the coupled thermal-hydrological-mechanical (T-H-M) response of fractured geological media by the computational implementation of mathematical models. From the generalization of Biot's classical theory of consolidation of a saturated porous elastic medium to include thermal effects, we first derived the equations governing coupled T-H-M processes in saturated geological media. In order to obtain numerical solutions for the governing equations, the finite element method was used. A finite element computer code, FRACON (FRActured media CONsolidation), was developed in order to simulate plane strain and axisymmetric problems. Eight-noded isoparametric elements were developed to represent the intact regions of the geological medium, while special joint elements were developed to simulate discrete joints. The intact regions of the geological medium was assumed to exhibit linear elasticbehaviour. The joints between intact regions were modelled by constitutive relationships which reproduced both linear elastic and nonlinear elasto-plastic responses. The elasto-plastic stress-strain relationship of the joint, was formulated by appeal to classical theories of interface plasticity. The elasto-plastic model for joint behaviour thus formulated is capable of reproducing many of the fundamental features of mechanical behaviour associated with naturally occuring joints, such as dilation under shear and strain softening due to surface asperity degradation. Furthermore, the thesis presents a physically-based hydraulic model of the joint that permits the inclusion of the effec The development of the FRACON code followed an extensive procedure of code verification via analytical solutions and intercode comparison. A unique set of benchmark problems was proposed in order to perform code verification for coupled T-H-M. The FRACON code was used to interpret certain laboratory and field experiments, including the following: (1) coupled T-H-M laboratory experiment on a block of cementitious material; (2) lab experiments on joint shear behaviour under constant normal stress and constant normal stiffness conditions; (3) coupled shear-flow laboratory experiment on a joint; (4) Field experiments of fluid injection in a horizontal fracture in a granitic rock mass. Lastly, the FRACON code was used to simulate the coupled T-H-M response of a rock mass to radiogenic heat from nuclear fuel wastes buried in the rock formation. The coupled H-M response of this rock mass to a future glaciation scenario was also simulated. It was shown that the mechanical/hydraulic regimes of the rock mass could be significantly changed by the above two factors. The importance of the consideration of T-H-M processes in the overall scheme of safety assessment of sites targeted for nuclear fuel waste repositories is supported by the findings of this thesis.

APA, Harvard, Vancouver, ISO, and other styles

26

Alfvén, Linda. "Structural and Engineering Geological Investigation of Fracture Zones and Their Effect on Tunnel Construction." Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-272495.

Full text

Abstract:

This thesis project was conducted in connection with the project, Stockholm’s future sewer pipeline, which is a planned sewer pipe that will run through a tunnel from western to southern Stockholm. This tunnel will pass under Lake Mälaren between Eolshäll and Smedslätten, where there are two faults indicated on the geological map, that could affect the tunnelling and create risks during the construction. Geophysical- and water-loss measurements along with core drilling have been carried out in the area. The objectives of this thesis are to create a structural and engineering geological understanding of the passage beneath Lake Mälaren based on drill core mapping, field work, data from previous investi-gations and 2D-models of the tunnel excavation both within and outside the indicated fault zone. The core mapping supports the existence of one fault zone, which is indicated on the geological map supported by water-losses at several places along the drill core as well as core losses. Field work indi-cated the existence of a conjugate fracture sets.The 2D-models present plastic behaviour of the rock in the fault zone as the worst case scenario during excavation with the highest deformation displacement. The excavation procedure and the tunnel form also play a significant role. Since this thesis highlights some significant risks and problems that can occur during tunnelling, its findings may be useful during the tunnel construction. Denna uppsats är skriven med koppling till projektet, Stockholms framtida avloppsledning, vilket inkluderar en ny tunnel för transport av avloppsvatten från västra till södra Stockholm. Tunneln kommer att passera under Mälaren mellan Smedslätten och Eolshäll, där det är två förkastningar indikerade på geologiska kartor som kan orsaka stora risker för byggnationen av tunneln. Geofysiska mätningar, kärnborrning och vattenförlustmätning har tidigare utförts i området. Målen för denna uppsats är att skapa en geologisk- och bergmekanisk förståelse för tunnelpassagen under Mälaren utifrån kärnkartering, fältarbete, data från tidigare undersökningar och 2D-modeller av tunneluttag i den indikerade zonen och utanför. Kärnkarteringen stödjer existensen av en förkastningszon som finns på den geologiska kartan. Flertalet vattenförluster är indikerade längs med hela kärnan tillsammans med en del förekomster av kärnförluster. Fältarbetet indikerar på förekomst av ett konjugerande sprickset. 2D-modeller över tunneln visade att olika egenskaper på berget samt hur uttaget av tunneln sker har betydelse för deformationernas storlek. Den här uppsatsen belyser några viktiga problem och risker som kan uppstå under tunnelbyggnationen, dessa upptäckter kan därför vara användbara och värdefulla under hela byggnationen.

APA, Harvard, Vancouver, ISO, and other styles

27

St, John Thomas William. "The distribution and assessment of sulfur-species in geological materials : implications for geoenvironmental engineering." Thesis, University of Bristol, 2015. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.687594.

Full text

Abstract:

Sulfur-species in geological materials have detrimental consequences for geoenvirormental engineering. The research considers aspects of sampling, testing and assessment that were identified as in need of further investigation. Field and laboratory studies show that the distribution of sulfur-species with depth below ground level can be divided into three zones: an upper sulfate leached zone, an intermediate zone with sulfate-horizons and a lower sulfate-poor, sulfide-rich zone. Based on this zonation, a targeted sampling strategy for sulfur-species is presented and permits application of existing classifications for aggressive ground. Petrographic studies of mudrock aggregates reveal the variations in sulfur-species morphology. It is shown that both framboidal and euhedral pyrite can oxidise extensively and that expansion due to gypsum growth may comprise several stages. Dehydration of hydrous sulfate minerals during sample drying was found to be insignificant for typical sulfur-species concentrations. Where high levels of accuracy are required, air-drying (<40ºC) is suitable, however vacuum drying may be required to remove all water from clay soils. The UK gravimetric method for acid-soluble sulfate determination was found to suffer from numerous error sources, with ±0.1% S042- error possible. Use of ICP-OES/AES to quantify sulfate in an acid-extract improved accuracy by an order of magnitude, to an acceptable level for sulfate contents around the tolerance for geo-materials. ICP-OES/AES is recommended as the standard method, with gravimetry to be used only if the sample mass is increased ten-fold. A review of the limitations associated with derived chemical terms such as equivalent pyrite shows that each term relies heavily on assumptions that may not be valid under certain conditions, particularly in the presence of insoluble sulfates and organic sulfur. The geoenvirorunental implications of the research findings are discussed in the context of various ground engineering scenarios and best-practice recommendations are made.

APA, Harvard, Vancouver, ISO, and other styles

28

Klose, Christian. "Engineering geological rock mass characterisation of granitic gneisses based on seismic in-situ measurements /." [Zurich] : [s.n.], 2003. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=15265.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Lee, Tsz-hang. "Geological study and performance in soft ground tunnelling by TBM /." View the Table of Contents & Abstract, 2005. http://sunzi.lib.hku.hk/hkuto/record/B36276662.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Jafarpour, Behnam. "Estimation of channelized features in geological media using sparsity constraint." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/43040.

Full text

Abstract:

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2008. Includes bibliographical references (p. 86-89). In this thesis, a new approach is studied for inverse modeling of ill-posed problems with spatially continuous parameters that exhibit sparseness in an incoherent basis (e.g. a Fourier basis). The solution is constrained to be sparse in the transform domain and the dimension of the search space is effectively reduced to a low frequency subspace to improve estimation efficiency. The solution subspace is spanned by a subset of a discrete cosine transform (DCT) basis containing low-frequency elements. The methodology is related to compressive sensing, which is a recently introduced paradigm for estimation and perfect reconstruction of sparse signals from partial linear observations in an incoherent basis. The sparsity constraint is applied in the DCT domain and reconstruction of unknown DCT coefficients is carried out through incorporation of point measurements and prior knowledge in the spatial domain. The approach appears to be generally applicable for estimating spatially distributed parameters that are approximately sparse in a transformed domain such as DCT. The suitability of the proposed inversion framework is demonstrated through synthetic examples in characterization of hydrocarbon reservoirs. by Behnam Jafarpour. S.M.

APA, Harvard, Vancouver, ISO, and other styles

31

Cormier, Jacqueline. "Laboratory studies of near surface permafrost conditions in fine-grained soils from the Mackenzie valley, NWT." Thesis, University of Ottawa (Canada), 2009. http://hdl.handle.net/10393/28451.

Full text

Abstract:

Laboratory studies were conducted on fine-grained soils from the Mackenzie valley, N.W.T., Canada, to study the transient layer. Two laboratory models simulating repeated freeze-thaw cycles were placed in a walk-in freezer. Temperatures and pore water pressures were monitored along the soil columns during eleven freeze-thaw cycles. At the end of the testing program, soil moisture conditions and cryostructures were examined. Temperature and pore water pressure data were compared to computed results and the thaw consolidation theory, respectively. In both laboratory models, an ice-rich zone developed at the active layer and permafrost interface as a result of moisture migration to the freezing front. The high ice content zone was altered under extreme air temperature conditions. Distinct cryostructures were created after repeated freeze-thaw processes. The formation and shifting of the ice-rich zone provide useful information on moisture conditions and the cryostructures for further understanding the transient layer.

APA, Harvard, Vancouver, ISO, and other styles

32

Gaskin, Janet. "Intensive aDcp Survey of a Gravel-Bed River Confluence." Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28738.

Full text

Abstract:

An intensive survey of the high angle asymmetric gravel-bed confluence of the Fraser River Main Channel with Minto Side Channel, downstream of a mid-channel island, was conducted using an acoustic Doppler current profiler (aDcp) during the freshet in June, 2008 at a combined discharge of 7 500 m 3/s. The confluence was characterized by a vertical mixing interface, with the Minto high velocity core being advected downwards in the upstream part of the scour zone; weaker helical flow is evident in the main channel flow as it confines the strongly helical left bank flow. Apparent bed velocity generally followed the thalweg, with the highest values near 0.15 m/s occurring at the edges of the scour zone and along the elongated bed step. In plotted spatial distributions, the areas of high primary bed velocity matched areas of high shear velocity and/or strongly upward vertical flow velocity.

APA, Harvard, Vancouver, ISO, and other styles

33

Lu, Lu. "A simple technique for estimating the one-dimensional heave of natural expansive soils." Thesis, University of Ottawa (Canada), 2010. http://hdl.handle.net/10393/28750.

Full text

Abstract:

Expansive soils are considered to be a nightmare to the geotechnical engineers. As the losses to the infrastructure constructed on expansive soils is estimated to be in billions of dollars world wide annually, several researchers and practitioners from various regions of the world have made significant contributions to better our present understanding of these problematic soils. One of the topics that attracted interest is related to the 1-D heave prediction or estimation methods for expansive soils. Early research studies on this topic were focused on developing empirical relationships which are not universally valid. Current techniques use soil suction methods and oedometer test methods to predict or estimate the 1-D heave; however, the various soil parameters required in these techniques can only be obtained from time consuming laboratory or in-situ tests that are expensive and difficult to be performed by conventional geotechnical engineers. In the present study, a simple technique is proposed to estimate the 1-D heave in expansive soils which requires only the information of plasticity index, Ip and variation in water content with respect to depth in the active zone. This technique is developed using the results of 5 case studies published in the literature. In addition to these case studies, 8 other case studies results of 1-D heave in expansive soils are summarized. The data of 13 of the case studies is collected from various regions of the world which include Australia, Canada, Chile, Saudi Arabia, Sudan, United States and Yugoslavia. Comparisons are provided between the measured and estimated 1-D heave for all the case studies have been using the proposed simple technique. There is a reasonably good comparison between the measured heave and the estimated heave for 8 of the 13 case studies results (i.e., less than 30%). The estimated heave is more than the measured heave for all the case studies; which is conservative from an engineering practice perspective. The reasons associated with the discrepancies between the measured and predicted 1-D heave values for the remainder of the five case studies are also discussed. The proposed simple technique is encouraging for the practicing geotechnical engineers in the estimation of 1-D heave in expansive soils.

APA, Harvard, Vancouver, ISO, and other styles

34

Ramsay, Andrea. "The impact of climate change on flood frequency distributions: A case study of the Kemptville Creek watershed." Thesis, University of Ottawa (Canada), 2011. http://hdl.handle.net/10393/28903.

Full text

Abstract:

Distributions of future extreme hydrologic events represent a major concern in the context of climate change and its potential impacts. The accurate inference of their probability distribution for a given period (present or future) is crucial for the safe and economic design of a range of engineering works, from hydraulic structures such as dam spillways and bridges, to flow routing infrastructure such as culverts, stormwater ponds and channels. These distributions are likely to evolve with climate change and the development of methods to estimate possible impacts on extreme event distributions has become a key area of study. In this study the impact of climate change on flood frequency distributions is ascertained through a combination of physical modeling and statistical analysis. This approach utilizes two of the most valuable tools in the field; general circulation models (GCMs) and non-stationary extreme value analysis, and seeks to capitalize on the strengths of established methods while limiting the number of unnecessary assumptions.

APA, Harvard, Vancouver, ISO, and other styles

35

Jones, Trevor. "Fracture Sealing by Mineral Precipitation| The Role of Surface Heterogeneities on Precipitation-Induced Transport Property Alterations." Thesis, University of California, Irvine, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13424490.

Full text

Abstract:

Fractures are often leakage pathways for fluids through low-permeability rocks that otherwise act as geologic barriers to flow. Flow of fluids that are in chemical disequilibrium with the host rock can lead to mineral precipitation, which reduces fracture permeability. When fracture surfaces contain a single mineral phase, mineral precipitation leads to fast permeability reduction and fracture sealing. However, the feedback between precipitation and permeability may be disrupted by mineral heterogeneities that localize precipitation reactions and provide paths of low-reactivity for fluids to persist over relatively long time-scales. In this dissertation, I explore the role of mineral heterogeneity on precipitation-induced permeability reduction in fractures. To do this, I use a combined experimental and numerical approach to test three hypotheses: (1) Mineral heterogeneity prolongs fracture sealing by focusing flow into paths with limited reactive surface area, (2) Precipitation-induced transport alterations at the fracture-scale are controlled by three-dimensional growth dynamics at the grain-scale, and (3) The effects of mineral heterogeneity become more pronounced as mineralogy and surface roughness become autocorrelated over similar length-scales. Direct measurements of mineral precipitation using transmitted light methods in a transparent analog fracture show that mineral heterogeneity can lead to the progressive focusing of flow into paths with limited reactive surface area, which is in support of (1). In this experiment, flow focusing led to a 72% reduction in the max precipitation rate; measurements of the projected mineralogy show that this was due to focusing of large dissolved ion concentrations into regions that contained 82% less reactive surface area than the fracture-scale average. Results from a newly developed reactive transport model that simulates precipitation-induced fracture surface alterations as a three-dimensional process are in good qualitative agreement with these experimental observations. Comparison of these results with a reactive transport model that represents precipitation as a 1D alteration of the fracture surfaces show that this flow-focusing process is driven by lateral growth of reactive minerals across the fracture-plane, which supports (2). Lastly, results from simulations in fractures that contain varied degrees of heterogeneity show that precipitation leads to a competition between two feedbacks: (i) precipitation-induced reactive surface area enhancement, which increases precipitation rates, and (ii) precipitation-induced permeability reduction, which decreases precipitation rates. When surface roughness and mineral heterogeneity provide persistent paths of limited surface area, the reactive transport becomes very sensitive to local permeability reduction. Simulation results show that this prolongs the fracture-sealing process and can lead to a reduction in fracture-scale precipitation rate, which supports (3). Furthermore, the results presented in this dissertation demonstrate that predictions of fracture sealing by mineral precipitation can be easily misinformed by studies that ignore small-scale mineral heterogeneity and neglect the three-dimensional nature of precipitation-induced fracture surface alterations.

APA, Harvard, Vancouver, ISO, and other styles

36

Waganaar, Spencer. "Influence of median grain size ratio on the strength and liquefaction potential of loose granular fills." Thesis, Florida Atlantic University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10172612.

Full text

Abstract:

The characterization of silty soils is usually designated by the percentage of silt contained within the soil matrix, along with the soil’s void ratio, which is used to describe the soil’s current state. The use of these parameters to assess a soil’s strength and undrained behavior is limited when finer material is contained within the soil. Therefore, additional parameters must be considered in order to correctly assess the strength and liquefaction potential of silty soils. These additional parameters include the skeleton void ratio, equivalent void ratio and granulometric factors. The current research investigates the influence of granulometric parameters, specifically the Median Grain Size Ratio (D50/ d50), denoted as μDR (or MDR within graphs and charts), on the strength and liquefaction potential of loose silty sands. A series of undrained monotonic triaxial compression tests (σ3’= 69, 83, and 103 kPa) are performed on reconstituted soil samples, using three different base sand samples and a constant silt material. As a result, three distinct median grain size ratios (μDR = 4.2, 6.75, and 9) were tested with fines content ranging from 0-30% for each μDR. The undrained shear strength at all confining pressures tends to increase with in μDR; beyond 10% fines content there was no noticeable influence of μDR. At any μDR the excess PWP is higher than that of clean sand, when fines content is larger than 5% fines content. The slope of the instability line and phase transformation line are directly affected by the μDR and fines content, with an increase in the instability line and decrease in the phase transformation line with a growing μ DR. The results indicate loose granular fills can be designed to be stronger and more resilient under extreme conditions by careful choice of materials in which the μDR>6.75 and the fines content does not exceed 10%.

APA, Harvard, Vancouver, ISO, and other styles

37

MacMinn, Christopher William. "Analytical modeling of CO₂ migration in saline aquifers for geological CO₂ storage." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45642.

Full text

Abstract:

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. Includes bibliographical references (p. 53-55). Injection of carbon dioxide into geological formations for long-term storage is widely regarded as a promising tool for reducing global atmospheric CO₂ emissions. Given the environmental and health risks associated with leakage of CO₂ from such a storage site, it is critical to ensure that injected CO₂ remain trapped underground for the foreseeable future. Careful site selection and effective injection methods are the two primary means of addressing this concern, and an accurate understanding of the subsurface spreading and migration of the CO₂ plume during and after injection is essential for both purposes. It is well known that some CO₂ will be trapped in the pore space of the aquifer rock as the plume migrates and spreads; this phenomenon, known as capillary trapping, is an ideal mechanism for geological CO₂ storage because the trapped gas is immobile and distributed over a large area, greatly decreasing the risk of leakage and enhancing the effectiveness of slower, chemical trapping mechanisms. Here, we present an analytical model for the post-injection spreading of a plume of CO₂ in a saline aquifer, both with and without capillary trapping. We solve the governing equation both analytically and numerically, and a comparison of the results for two different initial plume shapes demonstrates the importance of accounting for the true initial plume shape when capillary-trapping effects are considered. We nd that the plume volume converges to a self-similar, power-law trend at late times for any initial shape, but that the plume volume at the onset of this late-time behavior depends strongly on the initial shape even for weakly trapping systems. by Christopher William MacMinn. S.M.

APA, Harvard, Vancouver, ISO, and other styles

38

Sanders, Jonathon D. "Developing a GIS Tool for Infinite Slope Stability Analysis (GIS-TISSA)." Thesis, Michigan Technological University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10617403.

Full text

Abstract:

The Probabilistic Infinite Slope Analysis model (PISA-m) is a widely used computer program that uses infinite slope equations to calculate the spatially varying Factor of Safety of slopes. ESRI’s ArcGIS software and accompanying geoprocessing tools have become a mainstay in spatial data processing, and received full support for Python with the release of version 10. With many of the geoprocessing tools now available as a Python function, the software can be used for physics-based spatial landslide hazard analysis. A model that mimics PISA-m and its processing of normally distributed soil properties was created using the Python utility as a tool for ArcGIS. The newly created ArcGIS tool is referred as the GIS Tool for Infinite Slope Stability Analysis (GIS-TISSA). The tool was tested using the example data from PISA-m and case-study data from the district of Kannur, Kerala, India. The results from both areas highlight how different slope calculations can affect the overall calculation of the Factor of Safety, as well as the new model’s ability to accurately predict Factor of Safety of slopes in an area.

APA, Harvard, Vancouver, ISO, and other styles

39

Kremor, Andrew George. "Engineering geological factors affecting slope stability in soft brown coal deposits : a South Australian example /." Title page, contents and abstract only, 1992. http://web4.library.adelaide.edu.au/theses/09PH/09phk898.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Coote, Timothy Philip. "Engineering geological investigation of the Brunner coal measures overburden for opencast mining Webb Block, Stockton." Thesis, University of Canterbury. Geological Sciences, 1991. http://hdl.handle.net/10092/3886.

Full text

Abstract:

Detailed engineering geological investigation of the Brunner Coal Measures overburden, Webb Block, Stockton Colliery, was carried out to determine the principal geotechnical constraints or 'Hazards' to continued opencast development. The Stockton Opencast Mine currently produces 600,000 tpa with plans to increase production to 1.2 million tpa. Within the overburden two main lithological units are recognised: coarse, massive, variably cemented sandstones (Unit 1); and fine laminated siltstones and mudstones which are variably carbonaceous and micaceous (Unit 2). The tine laminated unit has a pronounced strength anisotropy, whereas the coarse massive unit is essentially homogeneous. All the materials are within the low to medium strength categories (UCS < 75 MPa). The fine laminated unit dominates the lowest 10 m of overburden and the coarse massive unit the upper 10 m. An iso-ratio map is presented at 1 :5000 scale, and shows the percentage thickness distribution of both I ithotypes within the Webb Block. The Webb Block is divided by the major Augustus and Baynes Fault Zones into three natural mining blocks. Bedding concordant discontinuities within the overburden include minor bedding plane shears (1O-20mm thick) developed within monoclines, and more substantial shear zones, persistent over at least tens of metres, located at lithological contacts. The Baynes Fault Zone is a monocline developed over inferred faulting at depth, as is the Augustus Fault Zone. The later is more complex with a wider deformation zone (c.50 m) and has numerous impersistent fault plane exposures. Shearing and/or minor faulting is common throughout the Webb Block but more prevalent in close proximity to the major fault zones. Jointing is characterised by a parent joint system within which three joint sets, which strike N-S, Nand NE, have been recognised. Within each set fractures are widely spaced and highly persistent. Highwall failure at Webb occurs by toppling, complex wedge/collapse or translational block slide. A Geotechnical Hazards Plan is presented which shows all the major stability hazards within the Webb Block. The principal constraint to opencast development is the unfavourable orientation of geological structures relative to proposed highwall alignments. Instability is further exacerbated by surface and groundwater draining across the high walls with a resultant build up of seepage pressures within the rock mass. The presence of abandoned underground mine openings reduces the basal support for sections of highwall. With continued open pit development at Webb by strike cuts and up dip advance, potential highwall instability is best resolved by:- 1. Identification of potential stability hazards by reference to the Geotechnical Hazards Plan coupled with follow up field investigation. 2. Setting the highwalls at safe stand-off distances from the hazards, highwalls can either be located down dip short of the hazard, or up dip by stripping through the hazard zone.

APA, Harvard, Vancouver, ISO, and other styles

41

Semmens, Stephen Bradley. "An Engineering Geological Investigation of the Seismic Subsoil Classes in the Central Wellington Commercial Area." Thesis, University of Canterbury. Geological Sciences, 2010. http://hdl.handle.net/10092/4287.

Full text

Abstract:

The city of Wellington has a high population concentration and lies within a geologically active landscape at the southern end of the North Island, New Zealand. Wellington has a high seismic risk due to its close proximity to several major fault systems, with the active Wellington Fault located in the north-western central city. Varying soil depth and properties in combination with the close proximity of active faults mean that in a large earthquake rupture event, ground shaking amplification is expected to occur in Thorndon, Te Aro and around the waterfront. This thesis focuses on the area bounded by Thorndon Overbridge in the north, Wellington Hospital in the south, Kelburn in the west, and Oriental Bay in the east. It includes many of the major buildings and infrastructural elements located within the central Wellington commercial area. The main objectives were to create an electronic database which allows for convenient access to all available data within the study area, to create a 3D geological model based upon this data, and to define areas of different seismic subsoil class and depth to rock within the study area at a scale that is useful for preliminary geotechnical analysis (1:5,000. Borelogs from 1025 holes with accompanying geological and geotechnical data obtained from GNS Science and Tonkin & Taylor were compiled into a database, together with the results from SPAC microtremor testing at 12 sites undertaken specifically for this study. This thesis discusses relevant background work and defines the local Wellington geology. A 3D geological model of the central Wellington commercial area, along with ten ArcGIS maps including surficial, depth to bedrock, site period, Vs30, ground shaking amplification hazard and site class (NZS 1170.5:2004) maps were created. These outputs show that a significant ground shaking amplification risk is posed on the city, with the waterfront, Te Aro and Thorndon areas most at risk.

APA, Harvard, Vancouver, ISO, and other styles

42

Shaanika, Giesberta Naipopya. "Engineering geological mapping for urban development in low relief semi-arid regions (Outapi northern Namibia)." Diss., University of Pretoria, 2019. http://hdl.handle.net/2263/77881.

Full text

Abstract:

Considering the current lack of engineering geological mapping in urban developments in Namibia, it was necessary to pioneer the input of engineering geology in the planning of infrastructure. The benefits of engineering geological mapping in sustainable development were highlighted and present methodologies were explored, looking at their applicability to Namibia. The early activities of engineering geological mapping include terrain classification, which groups areas of terrain that have similar conditions. It applies the principle of homogeneity such that areas falling under one terrain class are treated the same during planning, as they are deemed to have the same impact on engineering structures. The traditional way of doing terrain classification places much reliance on topography features, such as valleys, streams, etc. However, this becomes fairly difficult to apply in flat lying areas where topographical features may not be readily visible from aerial photographs. Therefore, soil variability mapping using colour and texture, vegetation mapping, and damage distribution mapping or structural damage techniques were recommended to aid terrain classification in flat lying semi-arid environments. Employing these techniques, Outapi Town in northern Namibia was mapped, identifying four terrain classes. With subsequent testing methods, these were upgraded to just three engineering geological zones. The main geotechnical constraints identified include the possibility of collapse settlement given the aeolian nature of the Outapi soils, susceptibility to flooding attributed to the flat nature of the area with no properly defined pathways, potential for dispersion as the soils are rather fine and saline, and, to a lesser extent, the presence of potentially expansive soils. Dissertation (MSc)--University of Pretoria, 2019. Geology MSc Unrestricted

APA, Harvard, Vancouver, ISO, and other styles

43

Warren, Sean N. "Empirical Ground Support Recommendations and Weak Rock Mass Classification for Underground Gold Mines in Nevada, USA." Thesis, University of Nevada, Reno, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10126161.

Full text

Abstract:

Ground conditions at underground gold mines in Nevada range from good to extremely poor and implementing the most appropriate ground support can be challenging. Existing empirical ground support design methods were developed predominantly from experience in tunneling or more competent ground, making them less applicable to underground gold mining in Nevada. This research presents empirically derived support guidelines from experience at 5 underground gold mines in Nevada, including: discussions with engineers and miners, review of ground control management plans and consulting documents, and roughly 400 ground control case-studies. Support design recommendations are based on the Weak-Rock Mass Rating (W-RMR) which is a modified Rock Mass Rating (RMR) classification incorporating the Unified Soil Classification System (USCS) for very weak rock masses. Ground support recommendations include rock bolt pattern support pressure, rock bolt length category, excavation surface support, and excavation strategy.

APA, Harvard, Vancouver, ISO, and other styles

44

Poeck, Eric C. "Analyzing the potential for unstable mine failures with the calculation of released energy in numerical models." Thesis, Colorado School of Mines, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10194982.

Full text

Abstract:

Unstable failure in underground mining occurs when a volume of material is loaded beyond its strength and displaces suddenly. It is recognized on various scales, from small rock bursts to the collapse of pillars or entire sections of a mine. The energy that is released during smaller scale events is manifested through the ejection of material, which can pose a hazard to the safety of miners. Larger scale events generate seismic waves as mine workings are damaged and may entrap miners or terminate production. This dissertation focuses on the analysis of unstable failure in an underground room and pillar mining environment. The potential for violent pillar failure is assessed using numerical modeling techniques and a parametric approach to loading conditions and material strength properties. The magnitude of instability is quantified by calculating the release of kinetic energy that occurs as failure progresses in each simulation. Fundamental mechanisms associated with the release of kinetic energy are analyzed in a series of finite difference models, and the results are compared with analytical solutions to illustrate the applicability of the energy calculations to increasingly complex modes of failure. Back analyses are performed on two room and pillar mine collapse events from the western United States by constructing large-scale models and reproducing widespread failure. The values of energy released in two-dimensional models are extrapolated by assuming a depth of failure in the third direction, and the total energy values are compared to the documented seismic magnitudes from each collapse through empirical equations. With further development of this numerical modeling approach, energy consideration may be used to study the potential for instability in a wide variety of mining excavations and identify the associated range of hazards.

APA, Harvard, Vancouver, ISO, and other styles

45

Peluchette, Jason. "Optimization of Integrated Reservoir, Wellbore, and Power Plant Models for Enhanced Geothermal Systems." Thesis, West Virginia University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=1524651.

Full text

Abstract:

Geothermal energy has the potential to become a substantially greater contributor to the U.S. energy market. An adequate investment in Enhanced Geothermal Systems (EGS) technology will be necessary in order to realize the potential of geothermal energy. This study presents an optimization of a waterbased Enhanced Geothermal System (EGS) modeled for AltaRock Energy’s Newberry EGS Demonstration location. The optimization successfully integrates all three components of the geothermal system: (1) the present wellbore design, (2) the reservoir design, and (3) the surface plant design. Since the Newberry EGS Demonstration will use an existing well (NWG 55-29), there is no optimization of the wellbore design, and the aim of the study for this component is to replicate the present wellbore conditions and design. An in-house wellbore model is used to accurately reflect the temperature and pressure changes that occur in the wellbore fluid and the surrounding casing, cement, and earth during injection and production. For the reservoir design, the existing conditions, such as temperature and pressure at depth and rock density, are incorporated into the model, and several design variables are investigated. The engineered reservoir is modeled using the reservoir simulator TOUGH2 while using the graphical interface PetraSim for visualization. Several fracture networks are investigated with the goal of determining which fracture network yields the greatest electrical output when optimized jointly with the surface plant. A topological optimization of the surface is completed to determine what type of power plant is best suited for this location, and a parametric optimization of the surface plant is completed to determine the optimal operating conditions. The conditions present at the Newberry, Oregon EGS project site are the basis for this optimization. The subsurface conditions are favorable for the production of electricity from geothermal energy with rock temperatures exceeding 300°C at a well depth of 3 km. This research was completed in collaboration with AltaRock Energy, which has provided our research group with data from the Newberry well. The purpose of this thesis is to determine the optimal conditions for operating an Enhanced Geothermal System for the production of electricity at Newberry. It was determined that a fracture network consisting of five fractured zones carrying 15 kg/s of fluid is the best reservoir design out of those investigated in this study. Also, it was found that 100 m spacing between the fractured zones should be implemented as opposed to only 50 m of spacing. A double-flash steam power plant provides the best method of utilization of the geothermal fluid. For the maximum amount of electricity generation over the 30-year operating lifetime, the cyclone separator should operate at 205°C and the flash vessel should operate at 125°C.

APA, Harvard, Vancouver, ISO, and other styles

46

Motamedi, MohammadHosein. "Numerical Simulation of Mechanical Response of Geomaterials from Strain Hardening to Localized Failure." Thesis, University of Illinois at Chicago, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10295585.

Full text

Abstract:

The Sandia GeoModel is a continuum elastoplastic constitutive model which captures many features of the mechanical response for geological materials over a wide range of porosities and strain rates. Among the specific features incorporated into the formulation are a smooth compression cap, isotropic/kinematic hardening, nonlinear pressure dependence, strength differential effect, and rate sensitivity. This study attempts to provide enhancements regarding computational tractability, domain of applicability, and robustness of the model. A new functional form is presented for the yield and plastic potential functions. The model is also furnished with a smooth, elliptical tension cap to account for the tensile failure. This reformulation renders a more accurate, robust and efficient model as it eliminates spurious solutions attributed to the original form. In addition, this constitutive model is adopted in bifurcation analysis to track the inception of new localization and crack path propagation. For the post-localization regime, a cohesive-law fracture model, able to address mixed-model failure condition, is implemented to characterize the constitutive softening behavior on the surface of discontinuity. To capture propagating fracture, the Assumed Enhanced Strain (AES) method is invoked. Particular mathematical treatments are incorporated into the simulation concerning numerical efficiency and robustness issues. Finally, the aforementioned modified cap plasticity model is employed to investigate the nonlinear dynamic response of the earthen substructure of the rail. Studying the effects of high-speed trains on the track substructure.

APA, Harvard, Vancouver, ISO, and other styles

47

Dreiås, Gudrun Majala. "Engineering geological assessment and structural comparison of the Vollan and Ivasnasen rock slopes at Sunndal, Norway." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for geologi og bergteknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-20116.

Full text

Abstract:

This master thesis has interest in analyzing the two unstable rock slopes Ivasnasen and Vollan. These rock slopes are located in a U-shaped valley in Sunndal municipally (Møre & Romsdal, western Norway). The analyses are based on a combined approach using detailed geomorphic, structural and geological field mapping. This along with interpretation of high-resolution digital elevation models (DEM) and orthophotos, LIDAR-scans from one of the sites (Ivasnasen 2010 and 2011), numerical analysis, kinematic analysis, XRD analysis and laboratory testing. The two sites, Ivasnasen and Vollan are both unstable. Ivasnasen is classified with a historical rockslide and an unstable rock slope, this because a remaining unstable part is detected in the elongation of the back scarp for the historical rockslide. For Vollan an earlier event is still active. It is important to analyze both sides of the valley to get a best knowledge of the possible consequences and the history. The software Ante-Rockslide Topography (ART) is used to reconstruct and construct the topography for Ivasnasen. Detailed volume estimation is used further in the software Slope Local Base Level (SLBL) and a manual ART reconstruction in the PolyWork (software). The calculated volume estimates for the historical rockslide at Ivasnasen range from 5.2Mm3 -1.2Mm3 and from 0.6-2.1Mm3 for the unstable rock slope. The software Phase2 has been used for the numerical modeling. The reconstructed and constructed topography for Ivasnasen have been used for a detailed study of the parameters and trigger factors that affected the slope stability in Phase2.The back scarp at Vollan contains quartzite and the back scarp at Ivasnasen contains augen gneiss. The main failure mechanism is toppling at Vollan and planar sliding at Ivasnasen. The study of Vollan and Ivasnasen provides useful findings for the understanding of potential present rock slope instabilities.It has been concluded that it have been two different events at Ivasnasen, based on analyses that discovered two different back scarps. Due to the numerical modeling in Phase2 the main triggers at Ivasnasen is the groundwater table and most likely a progressive accumulation of rock weakening, where it also include rich biotite layers. A growing tension was build up in the cracks and the slope failed.For Vollan the analysis concludes that it is a really slow movement process acting. Due to the analyses that have been done until now shows that it cannot be characterized as significant movements. For this site it is important to do further investigations over a longer period to have a more determined conclusion. The analyses that have been done in this thesis can be used as good inputs to further investigations.

APA, Harvard, Vancouver, ISO, and other styles

48

Nash, Timothy Richard. "Engineering geological assessment of selected landslide dams formed from the 1929 Murchison and 1968 Inangahua earthquakes." Thesis, University of Canterbury. Geological Science, 2003. http://hdl.handle.net/10092/9342.

Full text

Abstract:

This study investigated the characteristics of 26 failed and non-failed landslide dams (Murchison dataset) formed in the northern part of the South Island, New Zealand, from the 1929 Murchison and 1968 Inangahua earthquakes. The dataset was compiled from a combination of engineering geological mapping, field investigations, aerial photography interpretation and a review of existing literature. Current analysis techniques have been applied to the investigated landslide dams to assess their ability to accurately predict the post-formation development (or ‘evolution’) of the dam overtime. This has allowed the recognition of a number of additional landslide dam attributes that influence long-term stability, allowing modification of the stability analysis techniques in current use. Dam, lake, catchment and landslide characteristics were collated and analysed for the Murchison dataset by distinguishing failed from non-failed landslide dams, and then assessing the parameters common to both. Parameters that influence the post-formation development of selected landslide dams in the dataset include the dam volume, catchment area above the point of blockage, average block size of material comprising the dam, slope angle of the downstream dam face, and rock mass anal material characteristics in the source area of the dam-forming landslide. The stability of the dams in the Murchison dataset was not significantly affected by rock type, landslide movement, or the state, distribution and style of the dam-forming landslide. Existing geomorphic indices were applied to selected dams in the dataset. The Impoundment, Blockage and Dimensionless Blockage Indices (Casagli and Ermini (1999); Ermini and Casagli (2003)) predicted the correct post-formation development for 58, 86, and 81% of the selected landslide dams in the Murchison dataset, respectively. Four landslide dams covering both failed and non-failed types were investigated in detail to assist with this analysis, two being stable dams impounding lakes, and two having failed ‘catastrophically’ post-formation. Detailed investigation was carried out on Lake Stanley landslide dam, which agrees with all three indices predicting post-formation development, and of Lake Matiri, Ram Creek and Rain Peak landslide dams for which the indices incorrectly predict their post formation development. This investigation has shown that the average block size (D₅₀) of the dam material strongly influences the post-formation development of the four dams studied in detail. Dams consisting of material. with larger(> 200mm) average block sizes correspond to stable dams; while those with small(< 100mm) average block size correspond to failed dams. Rainfall duration/ intensity and slope angle of the downstream dam face were also found to influence post-formation development of the dams. The recently formed and failed Poerua landslide dam on the West Coast of the South Island was included in the geomorphic index evaluation because of the excellent documentation available, together with the prediction of its long-term stability using the index approach. The D₅₀ of the material forming the landslide dam, and the landslide dam's basal (or footprint) length, were incorporated with the parameters used in the existing geomorphic indices to produce a new geomorphic index, the Modified Dimensionless Blockage Index (MDBI). This is defined as: [complicated equation here] where Ac is the catchment area (m²), At is the lake area (m²), Hd is the height of the dam (m), Lʄ is the length of the dam footprint (m), Vd is the volume of the dam (m³), and Vd is the volume of the mean block size forming the dam (cube of the D₅₀ expressed in m³). Calculated MDBI values for the two stable landslide dams (Lake Stanley and Lake Matiri) are less than 10 (8.90 and 6.94 respective]y), while those for three failed landslide dams (Rain Peak, Ram Creek and Poerua) are greater than 10 (10.75, 10.80 and 14.9, respective]y). This suggests that the MDBI can be tentative]y used as a tool in forecasting the post-formation development of a landslide dam, with MDBI values > 10 corresponding to catastrophic dam failure, and an MDBI value < 10 corresponding to probable longer-term stability. However, it is recommended that a wider landslide dam dataset be applied to the MDBI to further test its accuracy, and to refine the parameters used both for short-term stability assessment following impoundment, and for longer-term prediction of post-formation dam (and lake) development. Rainfall duration and maximum block size of the dam material also require further evaluation, and a refinement incorporating grading parameters (such as D₆₀/D₁₀) may provide a better estimation of the post-formation landslide dam development. It is clear from this study that the block size and grading of the landslide dam material (in particular matrix or block support) exert significant influence on dam longevity and evolution, and this is reflected in the substantial weighting given to D₅₀ in the MDBI.

APA, Harvard, Vancouver, ISO, and other styles

49

Nowicki, Lisa Ann. "Engineering geology considerations for realignment of interstate 70/76 across the landslide at New Baltimore, Somerset County, SW Pennsylvania." Kent State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=kent1302399443.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Lee, Tsz-hang, and 李子衡. "Geological study and performance in soft ground tunnelling by TBM." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B45014292.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Geological engineering'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles