To see the other types of publications on this topic, follow the link: In situ soil mixing.
Journal articles on the topic 'In situ soil mixing'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'In situ soil mixing.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Evans, C. W. "In situ soil mixing treatment of contaminated soils and groundwater: two case studies." Land Contamination & Reclamation 14, no. 1 (February 1, 2006): 57–67. http://dx.doi.org/10.2462/09670513.705.
Full text
2
Almadani, Emine, and Kaveh Dehghanian. "Numerical Analysis of Soft Soils Reinforced with Deep Mixing Column." Orclever Proceedings of Research and Development 1, no. 1 (December 31, 2022): 240–56. http://dx.doi.org/10.56038/oprd.v1i1.205.
Full textAbstract:
The deep mixing method is an in-situ soil improvement method in which the soil is mixed with cement and other binding materials. Within the scope of this study, two-dimensional numerical analyzes of a reinforced soil by deep mixing columns were carried out. Two different soft clay soil properties (Model 1 and Model 2) were used in the analyses. Analysis of two-dimensional models was done with PLAXIS 2D finite element program. The deformations, consolidation and compression obtained from Mohr-Coulomb and soft soil models were compared. The effects of soil properties and the length of the column, modulus of elasticity, diameter and distance between them were investigated for two models. As a result, it is thought that two-dimensional analyzes together with the modeling that will reflect the current site conditions can give reasonably realistic results if the soil properties are selected well and correctly before the construction phase.
3
Do, Jinung. "Frost Heaving and Induced Pressure of Unsaturated Interfacial Zone between Gravel Ballast and Subgrade." Applied Sciences 12, no. 6 (March 9, 2022): 2811. http://dx.doi.org/10.3390/app12062811.
Full textAbstract:
Most existing railroads are composed of gravel ballast. One of the major issues with gravel ballast is frost damage in cold regions. Gravelly soils are known to be not prone to frost action due to their low water retention capacity and high hydraulic conductivity. However, reports indicated continued frost damages resulting from the mixed zone between gravel ballast and subgrade. This study evaluated the frost heaving and induced pressure of gravel ballast–subgrade soil mixtures via 1D soil column testing in a cold chamber. Gravel ballast and subgrade soil were collected from the railroad in situ. Various mixing ratios and degrees of saturation were used as factors affecting the frost experiments. The mixtures were placed in the cold chamber, and vertical displacements and pressures were measured. Overall evaluations showed that gravelly soils are not a geomaterial prone to frost damage; however, the frost potential of gravel ballast increases as the degree of saturation and the mixing portion of the subgrade soil increase. Therefore, the interfacial zone between gravel ballast and subgrade soil, especially where possible mixing with low drainage exists, needs cautions of potential frost damage.
4
Higaki, Kanji, Takao Iwasaki, Tohru Sueoka, and Tetsuo Nagatoh. "In Situ Cleanup of VOCs Contaminated Cohesive Soil by Lime Mixing." Doboku Gakkai Ronbunshu, no. 546 (1996): 113–23. http://dx.doi.org/10.2208/jscej.1996.546_113.
Full text
5
KRAUSE, H. H., and D. RAMLAL. "IN SITU NUTRIENT EXTRACTION BY RESIN FROM FORESTED, CLEAR-CUT AND SITE-PREPARED SOIL." Canadian Journal of Soil Science 67, no. 4 (November 1, 1987): 943–52. http://dx.doi.org/10.4141/cjss87-089.
Full textAbstract:
Anion and cation resins were tested as sinks for nutrient ions under variable forest soil conditions. The resins, contained in nylon bags, were placed for periods of 4 wk below the forest floor of a softwood stand, and at approximately 7.5 cm depth on an adjacent clearcut with two different types of site preparation for tree planting. The soil was an Orthic Humo-ferric Podzol. Ion sorption below the forest floor, especially the sorption of ammonium, nitrate and phosphate, was strongly increased after clear-cutting of the forest. Sorption rates were generally lower in the mineral soil than immediately below the forest floor, except for nitrate and sulphate. Mixing of forest floor materials and fine logging debris into the mineral surface horizons generally increased resin sorption if compared to sorption in soil from which the forest floor had been removed. Resin sorption also revealed strong seasonal effects which may have been caused by changes in soil temperature and moisture. Key words: Ion exchange resin, forest soil fertility, seasonal nutrient fluctuation, site preparation
6
Hines, Mark E., Patrick M. Crill, Ruth K. Varner, Robert W. Talbot, Joanne H. Shorter, Charles E. Kolb, and Robert C. Harriss. "Rapid Consumption of Low Concentrations of Methyl Bromide by Soil Bacteria." Applied and Environmental Microbiology 64, no. 5 (May 1, 1998): 1864–70. http://dx.doi.org/10.1128/aem.64.5.1864-1870.1998.
Full textAbstract:
ABSTRACT A dynamic dilution system for producing low mixing ratios of methyl bromide (MeBr) and a sensitive analytical technique were used to study the uptake of MeBr by various soils. MeBr was removed within minutes from vials incubated with soils and ∼10 parts per billion by volume of MeBr. Killed controls did not consume MeBr, and a mixture of the broad-spectrum antibiotics chloramphenicol and tetracycline inhibited MeBr uptake by 98%, indicating that all of the uptake of MeBr was biological and by bacteria. Temperature optima for MeBr uptake suggested a biological sink, yet soil moisture and temperature optima varied for different soils, implying that MeBr consumption activity by soil bacteria is diverse. The eucaryotic antibiotic cycloheximide had no effect on MeBr uptake, indicating that soil fungi were not involved in MeBr removal. MeBr consumption did not occur anaerobically. A dynamic flowthrough vial system was used to incubate soils at MeBr mixing ratios as low as those found in the remote atmosphere (5 to 15 parts per trillion by volume [pptv]). Soils consumed MeBr at all mixing ratios tested. Temperate forest and grassy lawn soils consumed MeBr most rapidly (rate constant [k] = 0.5 min−1), yet sandy temperate, boreal, and tropical forest soils also readily consumed MeBr. Amendments of CH4 up to 5% had no effect on MeBr uptake even at CH4:MeBr ratios of 107, and depth profiles of MeBr and CH4consumption exhibited very different vertical rate optima, suggesting that methanotrophic bacteria, like those presently in culture, do not utilize MeBr when it is at atmospheric mixing ratios. Data acquired with gas flux chambers in the field demonstrated the very rapid in situ consumption of MeBr by soils. Uptake of MeBr at mixing ratios found in the remote atmosphere occurs via aerobic bacterial activity, displays first-order kinetics at mixing ratios from 5 pptv to ∼1 part per million per volume, and is rapid enough to account for 25% of the global annual loss of atmospheric MeBr.
7
Pietrzak, U., and N. C. Uren. "Remedial options for copper-contaminated vineyard soils." Soil Research 49, no. 1 (2011): 44. http://dx.doi.org/10.1071/sr09200.
Full textAbstract:
Total copper concentrations in some Victorian vineyard soils, due to the use of copper (Cu)-based fungicides, have increased to the point where remedial strategies need to be considered to avoid Cu toxicity. In Australia, the National Environment Protection (Assessment of Site Contamination) Measure recommends that total Cu concentrations in soil exceeding the threshold concentration of 100 mg/kg require environmental investigation. However, it is likely that some Cu-contaminated soils, to be used for horticultural purposes, will need to be remediated even if the total Cu concentration is <100 mg/kg. This paper examines some prospective remedial strategies for Cu-contaminated vineyard soils and demonstrates that, apart from stopping the addition of Cu, in situ remedial strategies are the only practical remedial options for Cu-contaminated vineyard soils. Active mixing, both lateral and vertical, of contaminated surface soil with less contaminated or uncontaminated deeper soil is an in situ and well-suited remedial option for most low and medium Cu-contaminated vineyard soils. The strategy relies on attenuation processes to be more effective. Other ameliorative strategies with potential as remedial options for low and medium Cu-contaminated soils, including phytoremediation and attenuation (liming and addition of organic matter), are also considered.
8
La Mori, Phillip, Elgin Kirkland, Harlan Faircloth, Robert Bogert, and Mark Kershner. "Combined thermal and zero-valent iron In Situ soil mixing remediation technology." Remediation Journal 20, no. 2 (March 2010): 9–25. http://dx.doi.org/10.1002/rem.20237.
Full text
9
Simon, John A. "Editor’s Perspective-Soil Mixing Gains Popularity as an In Situ Treatment Technology." Remediation Journal 23, no. 2 (March 2013): 1–4. http://dx.doi.org/10.1002/rem.21344.
Full text
10
Kitazume, Masaki. "Recent Development and Future Perspectives of Quality Control and Assurance for the Deep Mixing Method." Applied Sciences 11, no. 19 (October 1, 2021): 9155. http://dx.doi.org/10.3390/app11199155.
Full textAbstract:
The deep mixing method (DMM), an in situ soil stabilization technique, was developed in Japan and Nordic countries in the 1970s and has gained increased popularity in many countries. The quality of stabilized soil depends upon many factors, including its type and condition, the type and amount of binder, and the production process. Quality control and quality assurance (QC/QA) practices focus on stabilized soil, and comprises laboratory mix tests, field trial tests, monitoring and controlling construction parameters, and verification. QC/QA is one of the major concerns for clients and engineers who have less experience with the relevant technologies. In this manuscript, the importance of QC/QA-related activities along the workflow of deep mixing projects is emphasized based on the Japanese experience/results with mechanical mixing technology by vertical shaft mixing tools with horizontal rotating circular mixing blade. The current and recent developments of QC/QA are also presented.
11
Christensen, Andre F., Hailong He, Miles F. Dyck, E. Lenore Turner, David S. Chanasyk, M. Anne Naeth, and Connie Nichol. "In situ measurement of snowmelt infiltration under various topsoil cap thicknesses on a reclaimed site." Canadian Journal of Soil Science 93, no. 4 (September 2013): 497–510. http://dx.doi.org/10.4141/cjss2012-048.
Full textAbstract:
Christensen, A. F., He, H., Dyck, M. F., Turner, L., Chanasyk, D. S., Naeth, M. A. and Nichol, C. 2013. In situ measurement of snowmelt infiltration under various topsoil cap thicknesses on a reclaimed site. Can. J. Soil Sci. 93: 497–510. Understanding the soil and climatic conditions affecting the partitioning of snowmelt to runoff and infiltration during spring snow ablation is a requisite for water resources management and environmental risk assessment in cold semi-arid regions. Soil freezing and thawing processes, snowmelt runoff or infiltration into seasonally frozen soils have been documented for natural, agricultural or forested systems but rarely studied in severely disturbed systems such as reclaimed lands. The objective of this study was to quantify the snowmelt infiltration/runoff on phosphogypsum (PG) tailings piles capped with varying thicknesses of topsoil (0.15, 0.3, and 0.46 m) at a phosphate fertilizer production facility in Alberta. There are currently no environmental regulations specifying topsoil capping thickness or characteristics for these types of tailings piles. Generally, the function of the topsoil cap is to facilitate plant growth and minimize the amount of drainage into the underlying PG. Experimental plots were established in 2006 to better understand the vegetation and water dynamics in this reconstructed soil. In 2011, time domain reflectometry (TDR) probes and temperature sensors were installed at various depths for continuous, simultaneous, and automated measurement of composite dielectric permittivity (ɛeff) and soil temperature, respectively. An on-site meteorological station was used to record routine weather data. Liquid water and ice content were calculated with TDR-measured effective permittivity (ɛeff) and a composite dielectric mixing model. Spatial and temporal change of total water content (ice and liquid) revealed that snowmelt infiltration into the topsoil cap increased with increasing topsoil depth and net soil water flux from the topsoil cap into the PG material was positive during the snowmelt period in the spring of 2011. Given the objective of the capping soil is to reduce drainage of water into the PG material it is recognized that a capping soil with a higher water-holding capacity could reduce the amount of meteoric water entering the tailings.
12
Park, Chang-Hwan, Aaron Berg, Michael H. Cosh, Andreas Colliander, Andreas Behrendt, Hida Manns, Jinkyu Hong, Johan Lee, Runze Zhang, and Volker Wulfmeyer. "An inverse dielectric mixing model at 50 MHz that considers soil organic carbon." Hydrology and Earth System Sciences 25, no. 12 (December 17, 2021): 6407–20. http://dx.doi.org/10.5194/hess-25-6407-2021.
Full textAbstract:
Abstract. The prevalent soil moisture probe algorithms are based on a polynomial function that does not account for the variability in soil organic matter. Users are expected to choose a model before application: either a model for mineral soil or a model for organic soil. Both approaches inevitably suffer from limitations with respect to estimating the volumetric soil water content in soils with a wide range of organic matter content. In this study, we propose a new algorithm based on the idea that the amount of soil organic matter (SOM) is related to major uncertainties in the in situ soil moisture data obtained using soil probe instruments. To test this theory, we derived a multiphase inversion algorithm from a physically based dielectric mixing model capable of using the SOM amount, performed a selection process from the multiphase model outcomes, and tested whether this new approach improves the accuracy of soil moisture (SM) data probes. The validation of the proposed new soil probe algorithm was performed using both gravimetric and dielectric data from the Soil Moisture Active Passive Validation Experiment in 2012 (SMAPVEX12). The new algorithm is more accurate than the previous soil-probe algorithm, resulting in a slightly improved correlation (0.824 to 0.848), 12 % lower root mean square error (RMSE; 0.0824 to 0.0727 cm3 cm−3), and 95 % less bias (−0.0042 to 0.0001 cm3 cm−3). These results suggest that applying the new dielectric mixing model together with global SOM estimates will result in more reliable soil moisture reference data for weather and climate models and satellite validation.
13
Shah, Syed Husnain Ali, Umer Habib, Abdullah Mohamed, Mubashir Aziz, Qasim ur Rehman, and Asma Saleem. "Laboratory and In Situ Stabilization of Compacted Clay through Granite Waste Powder." Sustainability 14, no. 21 (November 3, 2022): 14459. http://dx.doi.org/10.3390/su142114459.
Full textAbstract:
The main objective of this study is to investigate the effect of granite waste powder on the behavior of compacted clay soil in both field and laboratory environments. Samples were collected from clay soil exposed at Karak, Khyber Pakhtunkhwa, Pakistan. The sampled soils contain kaolinite, illite, and montmorillonites. The samples were mixed with various quantities, i.e., 10%, 20%, 30%, and 40% by weight of granite waste powder collected from various stone industries in district Mansehra, Khyber Pakhtunkhwa, Pakistan. They were then subjected to a variety of geotechnical testing in both the laboratory and the field, following the standard ASTM procedures. The results show that mixing with granite-cutting waste enhances the quality of the soil in both the field and laboratory settings by increasing its bearing capacity (BC), dry density (DD), California-bearing ratio (CBR), unconfined compressive strength (UCS), penetration resistance, and angle of internal friction and by reducing the optimum moisture content, cohesion, porosity, void ratio, and saturation potential. The resulting improvement is mainly due to the stronger, denser, and less hydrophilic character of the constituents of the added rock powders than the raw soil. It is observed that adding 40% granite waste powder produces the best outcome. However, there is a significant difference in the magnitude of the impact on soil quality between the laboratory and field testing. Owing to differences in the testing environment, soil volume, and compaction effort and energy, the amount of improvement is higher in laboratory testing than in field testing.
14
Wilkinson, Marshall T., and Geoff S. Humphreys. "Exploring pedogenesis via nuclide-based soil production rates and OSL-based bioturbation rates." Soil Research 43, no. 6 (2005): 767. http://dx.doi.org/10.1071/sr04158.
Full textAbstract:
New dating techniques are available for soil scientists to test fundamental pedogenic ideas. Recent developments in applications of terrestrial in situ cosmogenic nuclides (TCN) from bedrock and saprolite allow the derivation of soil production rates, at scales ranging from local (sub-hillslope) to catchment wide, generally averaged over timescales of 104–105 years. Where soil depths are relatively constant over time, soil production rates equal transport rates and are thus essential to establishing sustainable erosion rates. TCN also allow the form of the soil production function to be compared to theoretical models—a difficult task previously. Furthermore, parameterised soil production functions can now be incorporated into numerical surface process models to test landscape evolution ideas. Bedrock and saprolite conversion to soil is demonstrably dependent on the overlying soil depth, and there is general agreement that weathering declines exponentially beyond maximum soil production, consistent with theory. Whether maximum soil production occurs under a finite or non-existent soil cover at particular sites remains unresolved. We suggest that, in general, soil production from saprolite declines exponentially with increasing depth, while production from bedrock follows a humped function. Estimates of the role of flora, fauna and processes such as freeze–thaw that mix soil mantles to depth, have been limited prior to optically stimulated luminescence (OSL) dating techniques. Recently derived OSL mixing rates extend the magnitude of previous partial, short-term bioturbation rates. In fact, bioturbation appears to be the most active pedogenic process operating in many soils, with freeze–thaw environments a noted exception. Although bioturbation far outweighs soil production, it does not always lead to homogenisation as is often reported. We maintain that the above-ground component of bioturbation, i.e. mounding, may alone, or particularly when combined with particle sorting via rainwash processes, lead to horizonisation and texture contrast soils in those materials that can be sorted such as mixtures of sand and clay. Together, TCN- and OSL-based estimates of hillslope soil transport and bioturbation, suggest significant rates of downslope soil mantle movement coupled with rapid mixing, contrary to in situ soil development models.
15
Kim, Sojeong, Yeontae Kim, Suhyung Lee, and Jinung Do. "Preliminary Study on Application and Limitation of Microbially Induced Carbonate Precipitation to Improve Unpaved Road in Lateritic Region." Materials 15, no. 20 (October 17, 2022): 7219. http://dx.doi.org/10.3390/ma15207219.
Full textAbstract:
Some road systems are unpaved due to limited governmental finance and fewer maintenance techniques. Such unpaved roads become vulnerable during heavy rainy seasons following restrained accessibility among cities and traffic accidents. Considering the circumstances, innovative and cost–effective approaches are required for unpaved roads. Microbially induced carbonate precipitation (MICP) is an emerging soil improvement technology using microbes to hydrolyze urea generating carbonate ions, and precipitates calcium carbonate in the presence of calcium ion. Induced calcium carbonate bonds soil particles enhancing stiffness and strength when the MICP reaction takes place within the soil system. This study introduces the use of microbes on unpaved road systems consisting of in situ lateritic soils. The MICP technology was implemented to improve soil strength through two approaches: surface spraying and mixing methods. A series of soil testing was performed with varying chemical concentrations to measure precipitation efficiency, strength, and quality for construction material and see the feasibility of the proposed methods. The laboratory test results indicated that the surface spraying method provided improved; however, it was highly affected by the infiltration characteristics of used soils. The mixing method showed promising results even under submerged conditions, but still required improvement. Overall, the proposed idea seems possible to apply to improving unpaved road systems in the lateritic region but requires further research and optimization.
16
Nguyen Dinh, Hung. "Strengthening soft soil for approach road after abutment by cement and fly ash." Transport and Communications Science Journal 71, no. 4 (May 28, 2020): 444–57. http://dx.doi.org/10.25073/tcsj.71.4.12.
Full textAbstract:
Approach road is an important structure of a bridge. Serviceability of a bridge is affected by the settlement of approach road, especially that on soft soil. One method that is usually applied for minimizing effect of settlement of approach road is to replace soft soil by hill soil. This method however may increase cost of projects in Mekong Delta area with a larger depth of soft soil. In this paper, soft soil strengthened by mixing it to cement and fly ash at different mix proportions was investigated. Test results from unconfined compression test and direct shear test of strengthened soft soil are compared to those of hill soil to determine the optimal mix proportion. Results showed that mixing 25kg cement and 75kg or 100kg fly ash to 1m3 soft soil increased its unconfined compressive strength and shear strength and are higher compared to those of hill soil. Strengthening in situ soft soil by using fly ash, industrial waste from thermal power plant, reduces cost of project and at the same time contributes to solving environmental problems.
17
Macadam, Anne, and Richard Kabzems. "Vegetation Management Improves Early Growth of White Spruce More Than Mechanical Site Preparation Treatments." Northern Journal of Applied Forestry 23, no. 1 (March 1, 2006): 35–46. http://dx.doi.org/10.1093/njaf/23.1.35.
Full textAbstract:
Abstract The Inga Lake trial was one of a series of site preparation trials established in the northern interior of British Columbia during the 1980s to determine effective means of establishing conifer plantations on sites with severe vegetation competition and unfavorable soil conditions. Vegetation control, burned windrows, high-speed mixing, bedding plow, breaking plow, and disk trenching treatments were evaluated on a site with high brush potential, relatively dense soils, and average nutrient availability. This article summarizes impacts of treatments on soil density, soil chemical properties, and tree nutrition 5, 10, and 15 years after treatments and on the growth of planted white spruce (Picea glauca [Moench] Voss) after 15 growing seasons. Mixing, bedding plow, and disk trenching treatments decreased soil density and improved nutrient availability relative to no treatment, and effects were still significant after 15 years. Soil carbon and nitrogen increased substantially over time in treatments where there was a vigorous re-establishment of the plant community after disturbance. Although vegetation control did not improve soil physical or chemical properties relative to no treatment, it ranked among the top four treatments, with burned windrows, mixing, and breaking plow, in terms of white spruce growth after 15 years.
18
Kornienko, Mykola, Veronika Zhuk, Samar Abed, and Igor Chegodaev. "EXPERIENCE OF FIXING A WEAK BASE FOUNDATION BY VERTICAL SOIL-CEMENT ELEMENTS USING DRILL-MIXING TECHNOLOGY." TECHNICAL SCIENCES AND TECHNOLOG IES, no. 2 (12) (2018): 290–96. http://dx.doi.org/10.25140/2411-5363-2018-2(12)-290-296.
Full textAbstract:
Urgency of the research. Most construction sites in Ukraine have soil conditions area created by weak soils. Permanent pursuit of economical of engineering solutions require the use of new design solutions in the construction on weak soils. Target setting. In the last years new ways to fixing base of foundations using drill-mixing technology are gaining popular-ity. In the process of drilling a special wing bit is a destruction of natural soil and mixing with cement solution. As a result of solidification mixture formed is solid soil-cement element. Actual scientific researches and issues analysis. It has been previously performed in the laboratory study of strength soil-cement vertical elements depending on the amount of cement composition "soil-cement"¸ water-cement ratio in the mixture clay-cement additives properties. In order to a preliminary assessment of effectiveness fixing foundation using drill-mixing technology numerical simulation was performed. Uninvestigated parts of general matters defining. Using the weak soils as the basis for foundations of buildings and structures is seen in view of the possible destruction of their structure and the development of non-uniform deformation. The research objective. Perform evaluation of the effectiveness of fixing the building foundations on the example of a real construction site. The statement of basic materials.. In practice fixing foundations was performed using drill-mixing technology at the con-struction site in the city of Kiev. The article presents data about the experience fixing of weak base foundation, composed bulk soils with the contents of construction and domestic garbage. Fixing performed by soil-cement vertical elements using drill-mixing technology. Conclusions. The choice of a rational scheme of «basis - the foundation - over ground part of the building» should be based on an objective assessment of the mechanical properties of soil, and bearing structures of the building. Applying the basics fixing technology has allowed to reduce the cost of foundation structures up to 20 %.
19
Pandey, Gunjan, Robert J. Weber, and Ratnesh Kumar. "Agricultural Cyber-Physical System: In-Situ Soil Moisture and Salinity Estimation by Dielectric Mixing." IEEE Access 6 (2018): 43179–91. http://dx.doi.org/10.1109/access.2018.2862634.
Full text
20
Onur, Mehmet İnanç, Mert Bıçakcı, Pınar Sezin Öztürk Kardoğan, Ahmet Erdağ, and Majid Aghlmand. "LABORATORY MODEL DESIGN FOR DEEP SOIL MIXING METHOD." Elektronički časopis građevinskog fakulteta Osijek 13, no. 24 (June 3, 2022): 59–69. http://dx.doi.org/10.13167/2022.24.6.
Full textAbstract:
One of the most critical problems in the construction sector is the inadequate bearing capacities of subsoils. To solve this problem, various soil improvement methods are employed. Soil improvement is defined as the improvement in soil properties to the desired level by using various methods when the soil is not suitable for superstructure loads. Various types of soil improvement methods exist, and their application depends on the construction site, soil properties, earthquake zone, application time, and cost. One of the most widely used methods recently is the deep soil mixing method. In this study, a laboratory-scale deep soil mixing device is first developed; subsequently, the effects of injection pressure, mixing time, and dosing parameters on application are investigated. Deep soil mixing columns are prepared using different injection pressures, mixing times, and dosages and then subjected to the unconfined compression test. Results show that the effects of injection pressure, cement dosage, and mixing time on the unconfined compressive strength of deep soil mixing samples vary based on the initial soil properties.
21
Lake, Niels F., Núria Martínez-Carreras, Peter J. Shaw, and Adrian L. Collins. "High frequency un-mixing of soil samples using a submerged spectrophotometer in a laboratory setting—implications for sediment fingerprinting." Journal of Soils and Sediments 22, no. 1 (November 22, 2021): 348–64. http://dx.doi.org/10.1007/s11368-021-03107-6.
Full textAbstract:
Abstract Purpose This study tests the feasibility of using a submersible spectrophotometer as a novel method to trace and apportion suspended sediment sources in situ and at high temporal frequency. Methods Laboratory experiments were designed to identify how absorbance at different wavelengths can be used to un-mix artificial mixtures of soil samples (i.e. sediment sources). The experiment consists of a tank containing 40 L of water, to which the soil samples and soil mixtures of known proportions were added in suspension. Absorbance measurements made using the submersible spectrophotometer were used to elucidate: (i) the effects of concentrations on absorbance, (ii) the relationship between absorbance and particle size and (iii) the linear additivity of absorbance as a prerequisite for un-mixing. Results The observed relationships between soil sample concentrations and absorbance in the ultraviolet visible (UV–VIS) wavelength range (200–730 nm) indicated that differences in absorbance patterns are caused by soil-specific properties and particle size. Absorbance was found to be linearly additive and could be used to predict the known soil sample proportions in mixtures using the MixSIAR Bayesian tracer mixing model. Model results indicate that dominant contributions to mixtures containing two and three soil samples could be predicted well, whilst accuracy for four-soil sample mixtures was lower (with respective mean absolute errors of 15.4%, 12.9% and 17.0%). Conclusion The results demonstrate the potential for using in situ submersible spectrophotometer sensors to trace suspended sediment sources at high temporal frequency.
22
Struijk, Marijke, Andrew P. Whitmore, Simon R. Mortimer, and Tom Sizmur. "Obtaining more benefits from crop residues as soil amendments by application as chemically heterogeneous mixtures." SOIL 6, no. 2 (October 7, 2020): 467–81. http://dx.doi.org/10.5194/soil-6-467-2020.
Full textAbstract:
Abstract. Crop residues are valuable soil amendments in terms of the carbon and other nutrients they contain, but the incorporation of residues does not always translate into increases in nutrient availability, soil organic matter (SOM), soil structure, and overall soil fertility. Studies have demonstrated accelerated decomposition rates of chemically heterogeneous litter mixtures, compared to the decomposition of individual litters, in forest and grassland systems. Mixing high C:N ratio with low C:N ratio amendments may result in greater carbon use efficiency (CUE) and nonadditive benefits in soil properties. We hypothesised that nonadditive benefits would accrue from mixtures of low-quality (straw or woodchips) and high-quality (vegetable waste compost) residues applied before lettuce planting in a full factorial field experiment. Properties indicative of soil structure and nutrient cycling were used to assess the benefits from residue mixtures, including soil respiration, aggregate stability, bulk density, SOM, available N, potentially mineralisable N, available P, K, and Mg, and crop yield. Soil organic matter and mineral N levels were significantly and nonadditively greater in the straw–compost mixture compared to individual residues, which mitigated the N immobilisation occurring with straw-only applications. The addition of compost significantly increased available N, K, and Mg levels. Together, these observations suggest that greater nutrient availability improved the ability of decomposer organisms to degrade straw in the straw–compost mixture. We demonstrate that mixtures of crop residues can influence soil properties nonadditively. Thus, greater benefits may be achieved by removing, mixing, and reapplying crop residues than by simply returning them to the soils in situ.
23
Pan, Jun, Yuanqiu Liu, Xinyue Yuan, Junyi Xie, Jiehui Niu, Haifu Fang, Baihui Wang, et al. "Root Litter Mixing with That of Japanese Cedar Altered CO2 Emissions from Moso Bamboo Forest Soil." Forests 11, no. 3 (March 21, 2020): 356. http://dx.doi.org/10.3390/f11030356.
Full textAbstract:
Research Highlights: This study examined the effect of mixing fine roots of Japanese cedar with moso bamboo on soil carbon dioxide (CO2) emissions with nitrogen (N) addition treatment. Background and Objectives: Moso bamboo expansion into adjacent forests and N deposition are common in subtropical China. The effects of litter input on soil CO2 emissions, especially fine root litter input, are crucial to evaluate contribution of moso bamboo expansion on greenhouse gas emissions. Materials and Methods: An in situ study over 12 months was conducted to examine mixing fine roots of Japanese cedar with moso bamboo on soil CO2 emissions with simulated N deposition. Results: Fine root litter input of Japanese cedar and moso bamboo both impacted soil CO2 emission rates, with mixed litter, positively impact soil CO2 emission rate with N addition treatment. Moso bamboo fine root litter input decreased the sensitivity of soil CO2 emission rate to soil temperature. Conclusions: The encroachment of moso bamboo into adjacent forests might benefit soil C sequestration under warming climate, which will also benefit the mitigation of global climate change.
24
Al-Tabbaa, A., and C. W. Evans. "Laboratory-scale soil mixing of a contaminated site." Proceedings of the Institution of Civil Engineers - Ground Improvement 3, no. 3 (July 1999): 119–34. http://dx.doi.org/10.1680/gi.1999.030303.
Full text
25
Gonzalez-Meler, Miquel A., Armen Poghosyan, Yaniria Sanchez-de Leon, Eduardo Dias de Olivera, Richard J. Norby, and Neil C. Sturchio. "Does elevated atmospheric CO2affect soil carbon burial and soil weathering in a forest ecosystem?" PeerJ 6 (July 27, 2018): e5356. http://dx.doi.org/10.7717/peerj.5356.
Full textAbstract:
Most experimental studies measuring the effects of climate change on terrestrial C cycling have focused on processes that occur at relatively short time scales (up to a few years). However, climate-soil C interactions are influenced over much longer time scales by bioturbation and soil weathering affecting soil fertility, ecosystem productivity, and C storage. Elevated CO2can increase belowground C inputs and stimulate soil biota, potentially affecting bioturbation, and can decrease soil pH which could accelerate soil weathering rates. To determine whether we could resolve any changes in bioturbation or C storage, we investigated soil profiles collected from ambient and elevated-CO2plots at the Free-Air Carbon-Dioxide Enrichment (FACE) forest site at Oak Ridge National Laboratory after 11 years of13C-depleted CO2release. Profiles of organic carbon concentration,δ13C values, and activities of137Cs,210Pb, and226Ra were measured to ∼30 cm depth in replicated soil cores to evaluate the effects of elevated CO2on these parameters. Bioturbation models based on fitting advection-diffusion equations to137Cs and210Pb profiles showed that ambient and elevated-CO2plots had indistinguishable ranges of apparent biodiffusion constants, advection rates, and soil mixing times, although apparent biodiffusion constants and advection rates were larger for137Cs than for210Pb as is generally observed in soils. Temporal changes in profiles ofδ13C values of soil organic carbon (SOC) suggest that addition of new SOC at depth was occurring at a faster rate than that implied by the net advection term of the bioturbation model. Ratios of (210Pb/226Ra) may indicate apparent soil mixing cells that are consistent with biological mechanisms, possibly earthworms and root proliferation, driving C addition and the mixing of soil between ∼4 cm and ∼18 cm depth. Burial of SOC by soil mixing processes could substantially increase the net long-term storage of soil C and should be incorporated in soil-atmosphere interaction models.
26
Petkovšek, Ana, Matej Maček, and Jasna Smolar. "TESTING METHODS FOR MECHANICALLY IMPROVED SOILS: RELIABILITY AND VALIDITY." Acta Polytechnica CTU Proceedings 10 (October 15, 2017): 16. http://dx.doi.org/10.14311/app.2017.10.0016.
Full textAbstract:
A possibility of in-situ mechanical improvement for reducing the liquefaction potential of silty sands was investigated by using three different techniques: Vibratory Roller Compaction, Rapid Impact Compaction (RIC) and Soil Mixing. Material properties at all test sites were investigated before and after improvement with the laboratory and the in situ tests (CPT, SDMT, DPSH B, static and dynamic load plate test, geohydraulic tests). Correlation between the results obtained by different test methods gave inconclusive answers.
27
Ghumman, Ali Shaan Manzoor, Rashid Shamsuddin, Mohamed Mahmoud Nasef, Carmelo Maucieri, Obaid Ur Rehman, Arief Aizat Rosman, Mohamed Izzat Haziq, and Amin Abbasi. "Degradable Slow-Release Fertilizer Composite Prepared by Ex Situ Mixing of Inverse Vulcanized Copolymer with Urea." Agronomy 12, no. 1 (December 28, 2021): 65. http://dx.doi.org/10.3390/agronomy12010065.
Full textAbstract:
To improve the crop yield and nitrogen uptake efficacy, a novel slow-release urea composite fertilizer (SUCF) was developed using inverse vulcanized copolymer with better biodegradation and nutrient release longevity. Copolymers were synthesized via inverse vulcanization of jatropha oil, and their properties were evaluated using thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), powdered-X-ray diffractometry (p-XRD), and scanning electron microscopy (SEM). SUCFs were developed by ex situ mixing of inverse vulcanized copolymer with urea powder using mechanical mixer, and their properties were evaluated using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). FTIR spectra of developed fertilizer possesses the urea characteristics peaks along with the undisturbed peaks representing copolymer, confirming the mechanical mixing and that no reaction took place. SEM images of the SUCFs compared with images of copolymer revealed the appearance of new isolated particles with different morphology; EDX mapping showed that these particles represent the urea added to the copolymer. Nitrogen release longevity of developed fertilizers was evaluated in both soil and distilled water. The leaching test revealed that only 70% of the total nitrogen of SUCF prepared from 50 wt% sulfur copolymer was released after 16 days of incubation in distilled water, whereas it released only 35% nitrogen after 20 days in soil. The biodegradability of all copolymers developed was investigated by burying in soil and it revealed their biodegradable nature as weight loss was observed, which increased with the increase of incubation period.
28
Zotsenko, Mykola, Yuriy Vynnykov, Yevheniy Shokarev, and Аndriy Shokarev. "Reinforcement of the foundation base of the building with horizontal elements of increased rigidity." ACADEMIC JOURNAL Series: Industrial Machine Building, Civil Engineering 2, no. 51 (October 12, 2018): 156–60. http://dx.doi.org/10.26906/znp.2018.51.1308.
Full textAbstract:
A method for reducing the uneven deformations of a two-story building, which provides improving the construction properties of weak soils that lie at the base, by reinforcing them with horizontal soil-cement elements (SCE) of increased rigidity, carried out using a sand mixing technology, is described. SCEs are created in the mass under the base of the foundations and are formed as a result of the destruction of soil natural structure with its simultaneous mixing and injection of cement mortar under pressure. It has been established that the manufacture of SCE has a number of advantages: using of local soil as a material for their manufacture; adding to the soil only water and a binder, without additional aggregate; installation of elements on the site.
29
Fujiwara, Tadafumi, Hiroyasu Ishii, Makiko Kobayashi, and Tomoyuki Aoki. "Development and on-site application of new in-situ soil mixing method with ability of obstacle avoidance and inclined operation." Japanese Geotechnical Society Special Publication 2, no. 62 (2016): 2107–10. http://dx.doi.org/10.3208/jgssp.jpn-065.
Full text
30
Eldeeb, Mohammed, Vikram Narayanan Dhamu, Anirban Paul, Sriram Muthukumar, and Shalini Prasad. "An Interfacial Label-Free Electrochemical Approach to in-Situ Soil pH Monitoring." ECS Meeting Abstracts MA2022-02, no. 61 (October 9, 2022): 2275. http://dx.doi.org/10.1149/ma2022-02612275mtgabs.
Full textAbstract:
Soil is a critical entity of Earth’s ecosystem. Healthy soil supports a landscape that is more resilient to the impacts of drought, flood, or fire. It also helps regulate the Earth’s climate. Real time assessment of soil health is imperative to improving crop yield as well to sustain an ever growing human population. Soil health encompasses moisture content, phosphorus, pH, nitrate, and other parameters. One of the most important parameters is soil pH which affects nutrients availability to plants and nutrients leaching in the soil. Current soil pH assessment techniques require destructive sampling of the soil where a core of soil is collected then treated at a lab before measuring the pH. This method measures pH at time points and doesn’t provide a continuous real time monitoring of pH. This work utilizes commercial screen printed electrodes with a pH sensitive coating for low cost continuous in-situ soil pH measurement. The coating is made up from alizarin an anthraquinone compound that undergoes a redox reaction in the presence of hydrogen ions and nafion an ion permeable membrane. Square wave voltammetry (SWV) is utilized since the output current signal shows the redox of alizarin while rejecting the capacitive current that’s inherent in soil. This redox peak current potential is dependent on the concentration of hydrogen ions which is gives a direct measure of pH. Due to the sensitivity of SWV, it is possible to measure unbuffered soil ph (without CaCl2 and KCl to improve the electrolyte ionic strength) accurately. The nafion layer protects the alizarin from dissolving in water present in soil as well as promoting the diffusion of hydrogen ions into the coating thus improving sensitivity. The alizarin has been used previously in screen printed electrodes however, this is the first work to our knowledge to utilize it to measure soil pH in-situ over a period of time. The sensor output was first calibrated in different unbuffered soil textures against the gold standard glass electrode. The calibrated response of the sensor in unbuffered sandy loam soil slurry is shown in Fig. 1. Then the sensor accuracy was validated by testing different soil samples using the sensor and later mixing it with deionized water and measuring the pH using the glass electrode. The sensor’s stability was evaluated by taking a measurement every hour for 48 hours without removing it from the soil sample. The temporal study showed a coefficient of variation less than 1% and an average reading of within 0.3 pH of the actual pH of the soil sample. Fig. 1 Calibrated response of proposed sensor in sandy loam soil slurries with 40% water Figure 1
31
Ramon-Tarragona, Anna, and Eduardo Alonso. "Analysis of massive sulphate attack to cement-treated compacted soils." E3S Web of Conferences 195 (2020): 01009. http://dx.doi.org/10.1051/e3sconf/202019501009.
Full textAbstract:
The paper describes the heave experienced by two embankments providing access to a bridge located in a high-speed railway line. The compacted soil, a mixture of a low plasticity clay, sand and gravel, had a significant sulphate content (2 – 2.5%). The embankments received a reinforcing treatment by mixing the soil with cement in the proximity of the bridge abutments. In addition, a grid of grouting columns provided more stiffness to the embankments. The embankments experienced a fast heaving rate (around 4 mm/month) in the areas improved by cement mixing. Precision extensometers indicated that heave concentrated in the upper 6 – 8 m of the embankments. The sulphate content reduced sharply to 0.25% at increasing depth. No heave was detected in these deeper zones. The swelling was found to be associated with the development of thaumasite and ettringite minerals. The presence of clay, cement and sulphates in the compacted soils and the infiltration of water from rainfall events are ideal conditions for the growth of the mentioned minerals. Long-term tests performed on compacted samples provided a good evidence of the phenomena developing in situ. A chemical modelling of the mineral changes at the soil-cement interface provided an additional insight into the development of swelling, which could last for a long time (several years). Accordingly, it was decided to underpin the railway track and to excavate the upper active volume of the embankments. This solution went in parallel with train service, which was never interrupted.
32
Kanty, Piotr, Monika Kiecana, and Piotr Prokopowicz. "Some remarks on statistic approach to strength testing of soil-cement composites." E3S Web of Conferences 97 (2019): 04045. http://dx.doi.org/10.1051/e3sconf/20199704045.
Full textAbstract:
Results of laboratory testing of organic soil-cement samples are presented in the paper. The research program continues on the authors previously reported experiences with cement - organic soil sample testing. Over 150 compression tests have been carried out altogether. Several samples were cured for over 3 months before they were tested. Several factors, such as: the large amount of the pieces under test, long observation time, carrying out the tests in complex cycles of loading and the possibility of continuous registering the loads and deformation in the axial direction – made it possible to control numerous interdependencies, some of which have been presented in this work. Compressive strength and elastic modulus of cubic samples were examined. Samples were mixed and stored in laboratory conditions. The results clearly point to the fact that designing the DSM dry columns in the organic soil may be linked with a considerable risk and needs special precautions. During in situ mixing, the organic material surrounded by sand layers surely mixes with one another in certain areas. However, it has not been examined and it is difficult to assume such mixing already at the designing stage.
33
Hong, Yingwei, Xiaoping Wu, and Peng Zhang. "Construction Technology and Mechanical Properties of a Cement-Soil Mixing Pile Reinforced by Basalt Fibre." Advances in Materials Science and Engineering 2017 (2017): 1–14. http://dx.doi.org/10.1155/2017/9736465.
Full textAbstract:
A new type of cement-soil mixing pile reinforced by basalt fibre is proposed for increasing the bearing capacity of cement-soil mixing piles. This work primarily consists of three parts. First, the process of construction technology is proposed, which could allow uniform mixing of the basalt fibre in cement-soil. Second, the optimal proportions of the compound mixtures and the mechanical properties of the pile material are obtained from unconfined compression strength test, tensile splitting strength test, and triaxial shear test under different conditions. Third, the reliability of the construction technology, optimal proportions, and mechanical properties are verified by testing the mechanical properties of the drilling core sample on site.
34
Xia, Wei-Yi, Yan-Jun Du, Fa-Sheng Li, Chun-Ping Li, Xiu-Lan Yan, Arul Arulrajah, Fei Wang, and De-Jun Song. "In-situ solidification/stabilization of heavy metals contaminated site soil using a dry jet mixing method and new hydroxyapatite based binder." Journal of Hazardous Materials 369 (May 2019): 353–61. http://dx.doi.org/10.1016/j.jhazmat.2019.02.031.
Full text
35
Liu, Xue-Yan, Keisuke Koba, Lina A. Koyama, Sarah E. Hobbie, Marissa S. Weiss, Yoshiyuki Inagaki, Gaius R. Shaver, et al. "Nitrate is an important nitrogen source for Arctic tundra plants." Proceedings of the National Academy of Sciences 115, no. 13 (March 14, 2018): 3398–403. http://dx.doi.org/10.1073/pnas.1715382115.
Full textAbstract:
Plant nitrogen (N) use is a key component of the N cycle in terrestrial ecosystems. The supply of N to plants affects community species composition and ecosystem processes such as photosynthesis and carbon (C) accumulation. However, the availabilities and relative importance of different N forms to plants are not well understood. While nitrate (NO3−) is a major N form used by plants worldwide, it is discounted as a N source for Arctic tundra plants because of extremely low NO3− concentrations in Arctic tundra soils, undetectable soil nitrification, and plant-tissue NO3− that is typically below detection limits. Here we reexamine NO3− use by tundra plants using a sensitive denitrifier method to analyze plant-tissue NO3−. Soil-derived NO3− was detected in tundra plant tissues, and tundra plants took up soil NO3− at comparable rates to plants from relatively NO3−-rich ecosystems in other biomes. Nitrate assimilation determined by 15N enrichments of leaf NO3− relative to soil NO3− accounted for 4 to 52% (as estimated by a Bayesian isotope-mixing model) of species-specific total leaf N of Alaskan tundra plants. Our finding that in situ soil NO3− availability for tundra plants is high has important implications for Arctic ecosystems, not only in determining species compositions, but also in determining the loss of N from soils via leaching and denitrification. Plant N uptake and soil N losses can strongly influence C uptake and accumulation in tundra soils. Accordingly, this evidence of NO3− availability in tundra soils is crucial for predicting C storage in tundra.
36
Liu, Yong, Jun Hu, Huawen Xiao, and Elton J. Chen. "Effects of material and drilling uncertainties on artificial ground freezing of cement-admixed soils." Canadian Geotechnical Journal 54, no. 12 (December 2017): 1659–71. http://dx.doi.org/10.1139/cgj-2016-0707.
Full textAbstract:
The artificial ground freezing method can be used jointly with the deep cement mixing method during break-in and break-out processes of shield machines in a tunnel shaft. The frozen ground can fully cut off groundwater seepage, thus ensuring a watertight working platform. Cement-admixed soils can restrict frost heave and thaw-induced settlement because of the decreased permeability. Both methods can also enhance mechanical strength of the soil to enable construction to proceed. Two main sources of heterogeneity are likely to influence the freezing effect: spatial variability in in situ water content in natural soil and spatial variability in binder concentration in cement-admixed soils. Furthermore, positioning error when installing freeze pipes can also affect freezing efficiency. This study simulates in situ water content and binder concentration as Gaussian random fields, whereby variations in the thermophysical properties are estimated. Positioning error is also assessed by prescribing an incline angle in freeze pipes. The influences of those two sources of spatial variability as well as positioning error are examined with random finite-element analyses and statistical characteristics are estimated based on the results. Results are tabulated to offer practitioners a rule of thumb for estimating additional efforts needed in artificial ground freezing, accounting for variations in the thermophysical properties and positioning errors in installing freeze pipes.
37
LANDSBURG, S. "EFFECTS OF PIPELINE CONSTRUCTION ON CHERNOZEMIC AND SOLONETZIC A AND B HORIZONS IN CENTRAL ALBERTA." Canadian Journal of Soil Science 69, no. 2 (May 1, 1989): 327–36. http://dx.doi.org/10.4141/cjss89-033.
Full textAbstract:
The effects of pipeline construction on agricultural soil quality ratings were evaluated for the A and B horizons of Orthic Dark Brown Chernozem and Dark Brown Solonetz soils at three sites in Central Alberta 1 wk after construction. At each site, samples of the Ap horizon from the spoil side, trench, and work side portions of a pipeline right-of-way were compared to a sample of the Ap horizon from an adjacent area unaffected by pipeline construction. Spoil material below replaced topsoil on the trench was compared to a sample of an undisturbed B horizon. Regardless of soil type or land use, construction had no effect on the Ap horizon on the work side. This was due to optimum weather conditions during construction; low rainfall resulted in lack of soil rutting and minimal soil mixing. For both soil types under cultivation, construction increased soluble salt concentrations in the Ap horizons on the spoil side due to mixing of topsoil and spoil materials. There were few effects on the Ap horizon on the spoil side in pasture land, due to trench only topsoil stripping and easy spoil removal from a well-developed sod layer. Both the Ap and spoil from the trench in the Dark Brown Solonetz had increased salt concentrations, while there were few changes in the Dark Brown Chernozem. Mixing of topsoil and spoil material, and bringing salt-enriched material to the spoil surface are thought to be reponsible for the increase. For both soils and land uses, soil effects due to construction were reflected in the Ap horizon of the trench and spoil side by changes in pH, electrical conductivity, soluble salts and bulk density. Even with the increases in the soil properties monitored, the results indicated that regardless of soil type or land use, pipeline construction did not significantly affect the agricultural soil quality of the A and B horizons. Key words: Pipeline construction, solonetz, chernozem, work side, trench, spoil side
38
Kawamura, Masashi, and Yoshio Kasai. "Compressive Strength and Density of Fly-Ash Substituted Soil-Cement Concrete." Key Engineering Materials 302-303 (January 2006): 376–83. http://dx.doi.org/10.4028/www.scientific.net/kem.302-303.376.
Full textAbstract:
Soil-cement concrete can be manufactured by mixing portland cement, water and on-site soil and has been studied by the authors. This study deals with compressive strength and density of soil-cement concrete where the portland cement was partially substituted with fly-ash. Saturated surface-dry condition of on-site soils has never been taken into account in the conventional mix design whereas experiments of determining the saturated surface-dry conditions were carried out with the help of the concept of effective water content to assure the quality and the designed strength. Effects of fly-ash on the strength and density of soil-cement concrete were studied by altering cement-fly-ash ratio, soil-sand ratio, binder-water ratio and age under a constant unit water content
39
龚, 灵迪. "In-Situ Test Study of the Squeezing Effect on Adjacent Soil Due to Tri-Axial Cement Mixing Piling." Hans Journal of Civil Engineering 09, no. 09 (2020): 864–74. http://dx.doi.org/10.12677/hjce.2020.99091.
Full text
40
Denyes, Mackenzie J., Allison Rutter, and Barbara A. Zeeb. "In situ application of activated carbon and biochar to PCB-contaminated soil and the effects of mixing regime." Environmental Pollution 182 (November 2013): 201–8. http://dx.doi.org/10.1016/j.envpol.2013.07.016.
Full text
41
AlJassar, Hala K., Marouane Temimi, Dara Entekhabi, Peter Petrov, Hussain AlSarraf, Panagiotis Kokkalis, and Nair Roshni. "Forward Simulation of Multi-Frequency Microwave Brightness Temperature over Desert Soils in Kuwait and Comparison with Satellite Observations." Remote Sensing 11, no. 14 (July 11, 2019): 1647. http://dx.doi.org/10.3390/rs11141647.
Full textAbstract:
In this study, we address the variations of bare soil surface microwave brightness temperatures and evaluate the performance of a dielectric mixing model over the desert of Kuwait. We use data collected in a field survey and data obtained from NASA Soil Moisture Active Passive (SMAP), European Space Agency Soil Moisture and Ocean Salinity (SMOS), Advanced Microwave Scanning Radiometer 2 (AMSR2), and Special Sensor Microwave/Imager (SSM/I). In situ measurements are collected during two intensive field campaigns over bare, flat, and homogeneous soil terrains in the desert of Kuwait. Despite the prevailing dry desert environment, a large range of soil moisture values was monitored, due to precedent rain events and subsequent dry down. The mean relative difference (MRD) is within the range of ±0.005 m3·m−3 during the two sampling days. This reflects consistency of soil moisture in space and time. As predicted by the model, the higher frequency channels (18 to 19 GHz) demonstrate reduced sensitivity to surface soil moisture even in the absence of vegetation, topography and heterogeneity. In the 6.9 to 10.7 GHz range, only the horizontal polarization is sensitive to surface soil moisture. Instead, at the frequency of 1.4 GHz, both polarizations are sensitive to soil moisture and span a large dynamic range as predicted by the model. The error statistics of the difference between observed satellite brightness temperature (Tb) (excluding SMOS data due to radio frequency interference, RFI) and simulated brightness temperatures (Tbs) show values of Root Mean Square Deviation (RMSD) of 5.05 K at vertical polarization and 4.88 K at horizontal polarization. Such error could be due to the performance of the dielectric mixing model, soil moisture sampling depth and the impact of parametrization of effective temperature and roughness.
42
Wen, Hua, Song Gu, You Wen Su, and Bao Long Zhu. "Field Test Research on Treatment of Over-Wet Soil." Advanced Materials Research 261-263 (May 2011): 1003–8. http://dx.doi.org/10.4028/www.scientific.net/amr.261-263.1003.
Full textAbstract:
Take over-wet soil as research object, this paper presents the results of field test to verify the effect and feasibility of ash mixing method, one improvement technique for over-wet soil, on improving the performance of over-wet fill in construction site. This paper also studies the construction technology of utilization of over-wet fill in moist and rainy areas; determines construction parameters; summarizes construction techniques, methods and standards of quality control preliminary. The results show: ash mixing method can effectively improve the performance of over-wet fill; note that additives and over-wet fill should be fully stirred; this approach also works well for managing viscous silty sand.
43
Beskoski, Vladimir, Milos Takic, Jelena Milic, Mila Ilic, Gordana Gojgic-Cvijovic, Branimir Jovancicevic, and Miroslav Vrvic. "Change of isoprenoids, steranes and terpanes during ex situ bioremediation of mazut on industrial level." Journal of the Serbian Chemical Society 75, no. 11 (2010): 1605–16. http://dx.doi.org/10.2298/jsc100505091b.
Full textAbstract:
The paper presents results of the ex situ bioremediation of soil contaminated by mazut (heavy residual fuel oil) in the field scale (600 m3). A treatment-bed (thickness 0.4 m) consisted of mechanically mixed mazut-contaminated soil, softwood sawdust as the additional carbon source and crude river sand, as bulking and porosity increasing material. The inoculation/reinoculation was conducted periodically using a biomass of a consortium of zymogenous microorganisms isolated from the bioremediation substrate. The biostimulation was performed through addition of nutritious substances (N, P and K). The aeration was improved by systematic mixing of the bioremediation system. After 50 days, the number of hydrocarbon degraders increased 100 times. Based on the changes in the group composition, the average biodegradation rate during bioremediation was 24 mg/kg/day for the aliphatic fraction, 6 mg/kg/day for the aromatic fraction, and 3 mg/kg/day for the nitrogen-sulphuroxygen compounds (NSO)-asphaltene fraction. In the saturated hydrocarbon fraction, gas chromatography-mass spectrometry (GC-MS) in the single ion-monitoring mode (SIM) was applied to analyse isoprenoids pristane and phytane and polycyclic molecules of sterane and triterpane type. Biodegradation occurred during the bioremediation process, as well as reduction of relative quantities of isoprenoids, steranes, tri- and tetracyclic terpanes and pentacyclic terpanes of hopane type.
44
Salem Al-Qaisi, Maysa, and Maki Jafar Mohammed Al-Waily. "Experimental Study of Soft Clay Soil Improvement by Deep Mixing Method." Mathematical Modelling of Engineering Problems 9, no. 1 (February 28, 2022): 224–32. http://dx.doi.org/10.18280/mmep.090128.
Full textAbstract:
The deep method (DMM) is a soil remediation method that involves on-site mixing of soil with cement and/or other materials. These compounds, which are also known as "bonding materials," can be applied dry or wet. The current study involves the construction of 13 laboratory models to examine the means of improving soft clay soil qualities through deep mixing techniques with piling foundation. In the dry condition, static loading studies on piles and DMM were carried out using tow materials, cement, and lime. The model experiments included a single pile as well as groups of piles and cement or lime columns. There were two, three, and four piles or columns in each group. The model tests revealed that deep mixing had a significant impact on increasing bearing capacity by averaged times ranging from 1.23 to 2.43 times for soft clay soil treated with single and groups of four cement or lime columns, respectively, as well as minimizing settlement by averaged percentages ranging from 33% to 89 percent. These results were comparable to those obtained using pile foundations in the same manner. The outcomes of the model tests were also evaluated in terms of group efficiency.
45
Klaus, J., E. Zehe, M. Elsner, C. Külls, and J. J. McDonnell. "Macropore flow of old water revisited: where does the mixing occur at the hillslope scale?" Hydrology and Earth System Sciences Discussions 9, no. 4 (April 2, 2012): 4333–80. http://dx.doi.org/10.5194/hessd-9-4333-2012.
Full textAbstract:
Abstract. The mechanisms allowing the rapid release of stored water to streams are poorly understood. Here we use a tile drained field site to combine naturally structured soils at the hillslope scale with the advantage of at least partly controlled lower boundary conditions. We performed a series of three irrigation experiments combining hydrometric measurements with stable isotope and bromide tracers to better understand macropore-matrix interactions and stored water release processes at the hillslope scale. Stable isotope concentrations were monitored in the irrigation water, the tile drain discharge and the soil water before and after the experiment. Bromide was measured at mainly every 5–15 min in the tile drain hydrograph. Different initial conditions for each experiment were used to examine how pre-event soil moisture conditions influenced flow and transport. Different amounts of irrigation water were necessary to increase tile drain discharge above the base flow level. Hydrograph separation based on bromide data revealed that irrigation water contributions to peak tile drain discharge were on the order of 20%. Oxygen-18 and deuterium data were consistent with the bromide data and showed that pre-event soil water contributed significantly to the tile drain event flow. However, the isotopic composition of soil water converged towards the isotopic composition of irrigation water through the course of the experiment. Mixing calculations revealed that by the end of the irrigation experiments 20% of the soil water in the entire profile was irrigation water. The isotopic data showed that the pre-event water in the tile drain was mobilized in 20–40 cm soil depth were the macropore-matrix interaction leads to an initiation of macropore flow after a moisture threshold is exceeded.
46
Braakhekke, M. C., T. Wutzler, C. Beer, J. Kattge, M. Schrumpf, I. Schöning, M. R. Hoosbeek, B. Kruijt, P. Kabat, and M. Reichstein. "Modeling the vertical soil organic matter profile using Bayesian parameter estimation." Biogeosciences Discussions 9, no. 8 (August 21, 2012): 11239–92. http://dx.doi.org/10.5194/bgd-9-11239-2012.
Full textAbstract:
Abstract. The vertical distribution of soil organic matter (SOM) in the profile may constitute a significant factor for soil carbon cycling. However, the formation of the SOM profile is currently poorly understood due to equifinality, caused by the entanglement of several processes: input from roots, mixing due to bioturbation, and organic matter leaching. In this study we quantified the contribution of these three processes using Bayesian parameter estimation for the mechanistic SOM profile model SOMPROF. Based on organic carbon measurements, 13 parameters related to decomposition and transport of organic matter were estimated for two temperature forest soils: an Arenosol with a mor humus form (Loobos, The Netherlands), and a Cambisol with mull type humus (Hainich, Germany). Furthermore, the use of the radioisotope 210Pbex as tracer for vertical SOM transport was studied. For Loobos the calibration results demonstrate the importance of liquid phase transport for shaping the vertical SOM profile, while the effects of bioturbation are generally negligible. These results are in good agreement with expectations given in situ conditions. For Hainich the calibration offered three distinct explanations for the observations (three modes in the posterior distribution). With the addition of 210Pbex data and prior knowledge, as well as additional information about in situ conditions, we were able to identify the most likely explanation, which identified root litter input as the dominant process for the SOM profile. For both sites the organic matter appears to comprise mainly adsorbed but potentially leachable material, pointing to the importance of organo-mineral interactions. Furthermore, organic matter in the mineral soil appears to be mainly derived from root litter, supporting previous studies that highlighted the importance of root input for soil carbon sequestration. The 210Pbex measurements added only slight additional constraint on the estimated parameters. However, with sufficient replicate measurements and possibly in combination with other tracers, this isotope may still hold value as tracer for a SOM transport.
47
Braakhekke, M. C., T. Wutzler, C. Beer, J. Kattge, M. Schrumpf, B. Ahrens, I. Schöning, et al. "Modeling the vertical soil organic matter profile using Bayesian parameter estimation." Biogeosciences 10, no. 1 (January 24, 2013): 399–420. http://dx.doi.org/10.5194/bg-10-399-2013.
Full textAbstract:
Abstract. The vertical distribution of soil organic matter (SOM) in the profile may constitute an important factor for soil carbon cycling. However, the formation of the SOM profile is currently poorly understood due to equifinality, caused by the entanglement of several processes: input from roots, mixing due to bioturbation, and organic matter leaching. In this study we quantified the contribution of these three processes using Bayesian parameter estimation for the mechanistic SOM profile model SOMPROF. Based on organic carbon measurements, 13 parameters related to decomposition and transport of organic matter were estimated for two temperate forest soils: an Arenosol with a mor humus form (Loobos, the Netherlands), and a Cambisol with mull-type humus (Hainich, Germany). Furthermore, the use of the radioisotope 210Pbex as tracer for vertical SOM transport was studied. For Loobos, the calibration results demonstrate the importance of organic matter transport with the liquid phase for shaping the vertical SOM profile, while the effects of bioturbation are generally negligible. These results are in good agreement with expectations given in situ conditions. For Hainich, the calibration offered three distinct explanations for the observations (three modes in the posterior distribution). With the addition of 210Pbex data and prior knowledge, as well as additional information about in situ conditions, we were able to identify the most likely explanation, which indicated that root litter input is a dominant process for the SOM profile. For both sites the organic matter appears to comprise mainly adsorbed but potentially leachable material, pointing to the importance of organo-mineral interactions. Furthermore, organic matter in the mineral soil appears to be mainly derived from root litter, supporting previous studies that highlighted the importance of root input for soil carbon sequestration. The 210Pbex measurements added only slight additional constraint on the estimated parameters. However, with sufficient replicate measurements and possibly in combination with other tracers, this isotope may still hold value as tracer for SOM transport.
48
Schreier, Stefan F., Andreas Richter, and John P. Burrows. "Near-surface and path-averaged mixing ratios of NO<sub>2</sub> derived from car DOAS zenith-sky and tower DOAS off-axis measurements in Vienna: a case study." Atmospheric Chemistry and Physics 19, no. 9 (May 3, 2019): 5853–79. http://dx.doi.org/10.5194/acp-19-5853-2019.
Full textAbstract:
Abstract. Nitrogen dioxide (NO2), produced as a result of fossil fuel combustion, biomass burning, lightning, and soil emissions, is a key urban and rural tropospheric pollutant. In this case study, ground-based remote sensing has been coupled with the in situ network in Vienna, Austria, to investigate NO2 distributions in the planetary boundary layer. Near-surface and path-averaged NO2 mixing ratios within the metropolitan area of Vienna are estimated from car DOAS (differential optical absorption spectroscopy) zenith-sky and tower DOAS horizon observations. The latter configuration is innovative in the sense that it obtains horizontal measurements at more than a hundred different azimuthal angles – within a 360∘ rotation taking less than half an hour. Spectral measurements were made with a DOAS instrument on nine days in April, September, October, and November 2015 in the zenith-sky mode and on five days in April and May 2016 in the off-axis mode. The analysis of tropospheric NO2 columns from the car measurements and O4 normalized NO2 path averages from the tower observations provide interesting insights into the spatial and temporal NO2 distribution over Vienna. Integrated column amounts of NO2 from both DOAS-type measurements are converted into mixing ratios by different methods. The estimation of near-surface NO2 mixing ratios from car DOAS tropospheric NO2 vertical columns is based on a linear regression analysis including mixing height and other meteorological parameters that affect the dilution and reactivity in the planetary boundary layer – a new approach for such conversion. Path-averaged NO2 mixing ratios are calculated from tower DOAS NO2 slant column densities by taking into account topography and geometry. Overall, lap averages of near-surface NO2 mixing ratios obtained from car DOAS zenith-sky measurements, around a circuit in Vienna, are in the range of 3.8 to 26.1 ppb and in good agreement with values obtained from in situ NO2 measurements for days with wind from the southeast. Path-averaged NO2 mixing ratios at 160 m above the ground as derived from the tower DOAS measurements are between 2.5 and 9 ppb on two selected days with different wind conditions and pollution levels and show similar spatial distribution as seen in the car DOAS zenith-sky observations. We conclude that the application of the two methods to obtain near-surface and path-averaged NO2 mixing ratios is promising for this case study.
49
Jiang, Peng, Dazhuang Gui, Lina Wang, Hongchao Wang, and Shijie Zheng. "Study on the Factors Affecting the Quality of Trench Cutting Remixing Deep Wall in Qingdao Area." Geofluids 2021 (February 22, 2021): 1–12. http://dx.doi.org/10.1155/2021/6613052.
Full textAbstract:
As a new type of waterproof curtain, several station construction of Qingdao Metro Line 1 successfully used the trench cutting remixing deep wall (TRD). It is difficult to find the factors that affect the wall quality because the method is in situ underground excavating and mixing. This paper has obtained the main factors affecting the TRD quality in Qingdao by studying construction experience and carrying out tests. Geological conditions are fundamental factors. Among them, the parameters of medium-coarse sand layer, the groundwater table, and the humus content are the main factors. The design parameters are the key to high-quality TRD. In the design parameters, the depth inserting into the bedrock, the cement soil ratio, and the mixing time are important factors. And this paper proposes the methods of improving the wall quality, which can provide a theoretical guarantee for the follow-up application of the TRD in the Qingdao area.
50
Chapuis, Robert P., and Gaston Pouliot. "Determination of bentonite content in soilbentonite liners by X-ray diffraction." Canadian Geotechnical Journal 33, no. 5 (November 6, 1996): 760–69. http://dx.doi.org/10.1139/t96-101-322.
Full textAbstract:
The full-scale hydraulic performance of a soilbentonite liner depends on the homogeneity of bentonite content in the mix; any prediction must consider the distribution function of the local bentonite content, mainly that of below average values. The degree of homogeneity in the field depends on the mixing method and the sand characteristics. Several techniques, such as double hydrometer tests, or methylene blue tests, can evaluate the bentonite content in a sample. They are not reliable when the sand varies in gradation and mineralogy. This led to the investigation of whether X-ray diffraction could determine the bentonite content in a soilbentonite sample and a method was developed. First, the mix must be thermally treated to eliminate the variation in diffraction intensities resulting from the variable hydration of the montmorillonite. Then, an internal standard must be used to control the X-ray absorption. This paper presents the preliminary calibration work, the different steps to follow for quantitative determination of the bentonite content, its accuracy, and its application to a special project where the usual methods were not reliable due to a large variability in sand properties. The parameters needed to calculate the bentonite content in a mix depend on the type of bentonite but not on the type of sand. The accuracy depends on the variability in mineralogical quality of the bentonite powder. For one project, it is shown that the in situ mixing technique produced highly variable local bentonite contents, and that the average content was higher in the lower half of the lift than in its upper half. Key words: liner, bentonite, control, permeability.