Journal articles: 'Collapse of the soil'

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AL-Rawas, A. A. "State-of-the-Art-Review of Collapsible Soils." Sultan Qaboos University Journal for Science [SQUJS] 5 (December 1, 2000): 115. http://dx.doi.org/10.24200/squjs.vol5iss0pp115-135.

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Collapsible soils are encountered in arid and semi-arid regions. Such soils cause potential construction problems due to their collapse upon wetting. The collapse phenomenon is primarily related to the open structure of the soil. Several soil collapse classifications based on parameters such as moisture content, dry density, Atterberg limits and clay content have been proposed in the literature as indicators of the soil collapse potential. Direct measurement of the magnitude of collapse, using laboratory and/or field tests, is essential once a soil showed indications of collapse potential. Treatment methods such as soil replacement, compaction control and chemical stabilization showed significant reduction in the settlement of collapsible soils. The design of foundations on collapsible soils depends on the depth of the soil, magnitude of collapse and economics of the design. Strip foundations are commonly used when collapsing soil extends to a shallow depth while piles and drilled piers are recommended in cases where the soil extends to several meters. This paper provides a comprehensive review of collapsible soils. These include the different types of collapsible soils, mechanisms of collapse, identification and classification methods, laboratory and field testing, treatment methods and guidelines for foundation design.

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Al-otaibi, Fahad A., and Humoud Melfi Aldaihani. "DETERMINATION OF THE COLLAPSE POTENTIAL OF SABKHA SOIL AND DUNE SAND ARID SURFACE SOIL DEPOSITS IN KUWAIT." Jurnal Teknologi 83, no. 3 (April 1, 2021): 93–100. http://dx.doi.org/10.11113/jurnalteknologi.v83.14863.

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Ensuring the sustainability of critical and limited natural soil resources is a major challenge in arid regions such as Kuwait. Investigations should be performed to identify and characterise collapsible surface soil deposits, and collapse potential should be assessed if possible in order to evaluate suitable stabilizing techniques. The cementation effect of different types of salts gives arid soils their considerable strength and stiffness in dry conditions. The collapse in these soils may occur due to the reduction of the chemical or physical bonds between the soil particles under wet conditions. Collapse Potential (CP) is an indication of the collapsibility of these soils. This paper presents the results of experimental work that was carried out to evaluate the collapse potential of two types of surface soil: sabkha soil and dune sand. The experimental program included physical and chemical soil characterization alongside a modified compaction test. The collapsibility of the soil at a stress of 200 kPa was obtained by performing a Single Collapse Test (SCT) via a conventional odometer device in a temperature- and humidity-controlled environment. Collapse potential index tests were performed on the tested soil samples collected from eight locations in two study areas. The results suggest the problem severity is slight to none. However, the CP was higher for the sabkha soil samples than for the dune sand samples. The increase in collapsibility of the sabkha soil samples may be attributed to the removal of bonding between cementing particles upon wetting.

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Wang, Hong-Tao, Ping Liu, Chi Liu, Xin Zhang, Yong Yang, and Lu-Yao Liu. "Three-Dimensional Upper Bound Limit Analysis on the Collapse of Shallow Soil Tunnels considering Roof Stratification and Pore Water Pressure." Mathematical Problems in Engineering 2019 (November 11, 2019): 1–15. http://dx.doi.org/10.1155/2019/8164702.

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Based on the plastic upper bound theorem, a three-dimensional kinematically admissible velocity field is constructed for the collapse of the soil masses above a shallow tunnel. In this field, this paper considers the influences of the roof stratification, pore water pressure, ground overload, and support pressure. This study deduced the upper bound solutions of the weight of the collapsed soil masses and the corresponding collapse surfaces by utilizing the nonlinear failure criterion, associated flow rule, and variation principle. Furthermore, we verified the validity of the proposed method in this paper by comparing this research with the existing work and numerical simulation results. This study obtains the influence laws of varying parameters on the area and weight of the collapsed soil masses. The results reveal that the area and weight of the collapsed soil masses increase with increasing support pressure and soil cohesion, but decrease with increasing thickness of the upper soil layer, nonlinear coefficient, pore water pressure, and ground overload. Among them, the roof stratification, pore water pressure, soil cohesion, and nonlinear coefficient have a significant influence on tunnel collapse, which should be given special consideration in engineering design.

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Fattah, Mohammed Y., and Basma A. Dawood. "Time-dependent collapse potential of unsaturated collapsible gypseous soils." World Journal of Engineering 17, no. 2 (March 2, 2020): 283–94. http://dx.doi.org/10.1108/wje-09-2019-0276.

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Purpose This study aims to predict the volume changes and collapse potential (CP) associated with the changes in soil suction by using the pressure cell and the effect of initial load on soil suction. Three types of gypseous soils have been experimented in this study, sandy gypseous soil from different parts of Iraq. A series of collapse tests were carried out using the oedometer device [single oedometer test (SOT) and double oedometer test (DOT)]. In addition, large-scale model with soil dimensions 700 × 700 × 600 mm was used to show the effect of water content changes in different relations (collapse with time, stress with time, suction with time, etc.). Design/methodology/approach A series of collapse tests were carried out using the oedometer device (SOT and DOT). In addition, a large-scale model with soil dimensions 700 × 700 × 600 mm was used to show the effect of water content changes in different relations (collapse with time, stress with time, suction with time, etc.). Findings The CP increases with the increasing of the void ratio for each soil. For each soil, the CP decreased when the initial degree of saturation increased. Kerbala soil with gypsum content (30%) revealed collapse value higher than Tikrit soil with gypsum content (55%) under the same initial conditions of water content and density, this is because the higher the Cu value of Kerbala soil is, the more well-graded the soil will be. Upon wetting, the smaller particles or fractions of the well-graded soil tend to fill in the existing voids, resulting in a lower void ratio as compared to the poorly graded one. Consequently, soils with high Cu value tend to collapse more than poorly graded ones. The compressibility of the soil is low when loaded under unsaturated condition, the CP for samples tested in the DOTs under stress level 800 kPa are greater than those obtained from collapse test at a stress level of 200 kPa. Originality/value The initial value of suction for all soils increases with initial water content decreases.

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Wang, Hui Min, and Hua Jun Guo. "Collapse Cause Analysis and Treatment Research of West Slope Tunnel." Applied Mechanics and Materials 470 (December 2013): 954–57. http://dx.doi.org/10.4028/www.scientific.net/amm.470.954.

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Abstract: West Slope Tunnel's surrounding rock is broken. A positive step method is used in the reconstruction process of collapsed West Slope Tunnel. During tunnel construction process, heavy rain cause a landslide failure of tunnel (Located in DK51+175- DK51+195). The mainly collapsed area is located in the position of DK51+180. According to collapsing, we executed the settlement observation, cross-section deformation detection and upper crack observation.When collapse settlement is basically stable, the collapse is segmented to settle. The previous board of Secondary lining for the collapse need to add steel reinforcement and tunnel collapse cavity backfill C30 concrete. When concrete strength is expected ,it need to be excavated and must keep the core soil. The advanced small pipe is needed to stabilize the soil before the excavation section. In invasion of secondary lining collapse, girdle previous Primary Support and reform Primary Support.. Add I16 steel frame where necessary. We must strengthen the tunnel monitoring to ensure the safety during tunnel construction process.

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Xu, Linjuan, Yuanjian Wang, Wanjie Zhao, and Enhui Jiang. "Review on Riverbank Soil Collapse." MATEC Web of Conferences 246 (2018): 01021. http://dx.doi.org/10.1051/matecconf/201824601021.

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Bank slope collapse is a kind of natural phenomenon which commonly existed on both sides of alluvial plain rivers. The mechanism of bank collapse is complex, and it is an interdisciplinary frontier research subject. The collapse of the bank slope will lead to the instability of river regime and frequent changes of erosion and siltation, which will cause great harm to river regulation and people's livelihood. Through review of river bank soil collapse at home and abroad, it is concluded that the main influencing factors of river bank soil collapse are the action of water flow and the soil structure of river bank. In addition, the stability of river bank and the numerical simulation of river bank collapse are also studied by scholars. In view of the above research results, the deficiencies of the current research are pointed out and the research directions that should be followed in the future are put forward.

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7

Huang, D., J. D. Nelson, and S. Sharma. "Collapse potential of compacted soil." International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts 28, no. 6 (November 1991): A353. http://dx.doi.org/10.1016/0148-9062(91)91312-f.

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8

Tadepalli, Rambabu, and D. G. Fredlund. "The collapse behavior of a compacted soil during inundation." Canadian Geotechnical Journal 28, no. 4 (August 1, 1991): 477–88. http://dx.doi.org/10.1139/t91-065.

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The collapse behavior of a compacted, uncemented soil is studied within a theoretical context consistent with the concepts of unsaturated soil mechanics. Experimental data are presented relating the initial matric suction of a compacted soil to its volume decrease during inundation. The laboratory results indicate a unique relationship between the changes in matric suction (i.e., Δ(ua − uw), where ua is the pore-air pressure and uw is the pore-water pressure) of the compacted soil and the resulting volume reduction during inundation. Changes in the matric suction and total volume with respect to time were modelled using the theory of transient flow through an unsaturated soil. The predicted results show reasonable agreement with the experimental observations. The comparisons between the simulated results and the experimental data indicate that the coefficient of consolidation of the soil varies linearly with matric suction during the inundation process. Key words: unsaturated soil, matric suction, collapsible soils, negative pore-water pressures.

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Vilar, Orencio Monje, and Roger Augusto Rodrigues. "Collapse behavior of soil in a Brazilian region affected by a rising water table." Canadian Geotechnical Journal 48, no. 2 (February 2011): 226–33. http://dx.doi.org/10.1139/t10-065.

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Collapsible soils are usually nonsaturated, low density, and metastable-structured soils that are known to exhibit a volume reduction following an episode of moisture increase or suction reduction. This paper describes the collapsible behavior of clayey sand based on controlled soil suction tests carried out on undisturbed samples from the city of Pereira Barreto, in the State of São Paulo, Brazil. Foundation settlements due to soil collapse are common in this region and occurred during the filling of the reservoir of the Três Irmãos Dam, which induced the elevation of the groundwater table in different parts of Pereira Barreto. This paper shows that collapse strains depend on the stress and soil suction acting in the sample and that saturation is not necessary for a collapse to occur. The influence of soil suction, gradual wetting, and the wetting and drying cycle on the collapsible behavior of the soil is also shown and discussed.

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10

Rao, S. M., and K. Revanasiddappa. "Collapse behaviour of a residual soil." Géotechnique 52, no. 4 (May 2002): 259–68. http://dx.doi.org/10.1680/geot.2002.52.4.259.

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Rao, S. M., and K. Revanasiddappa. "Collapse behaviour of a residual soil." Géotechnique 52, no. 4 (May 2002): 259–68. http://dx.doi.org/10.1680/geot.52.4.259.41025.

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12

Ayadat, T. "ASSESSEMENT OF SOIL COLLAPSE PREDICTION METHODS." International Journal of Engineering 25, no. 1 (B) (February 2012): 17–24. http://dx.doi.org/10.5829/idosi.ije.2012.25.01b.03.

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13

Ayadat, Tahar, and Adel Hanna. "Prediction of collapse behaviour in soil." Revue Européenne de Génie Civil 11, no. 5 (May 2007): 603–19. http://dx.doi.org/10.1080/17747120.2007.9692947.

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14

Phanikumar, B. R., Rishi Raghav, and K. Bhargav. "Collapse behaviour of a lateritic soil." Geomechanics and Geoengineering 11, no. 2 (May 22, 2015): 119–24. http://dx.doi.org/10.1080/17486025.2015.1042925.

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Ayadat, Tahar, and Adel Hanna. "Prediction of collapse behaviour in soil." Revue européenne de génie civil 11, no. 5 (June 14, 2007): 603–20. http://dx.doi.org/10.3166/regc.11.603-620.

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16

Das, Amiya Prakash, and T. Thyagaraj. "Collapse behaviour of compacted red soil." International Journal of Geotechnical Engineering 12, no. 1 (October 20, 2016): 20–27. http://dx.doi.org/10.1080/19386362.2016.1243506.

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17

Vermeer, P. A., and H. Langen. "Soil collapse computations with finite elements." Ingenieur-Archiv 59, no. 3 (1989): 221–36. http://dx.doi.org/10.1007/bf00532252.

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18

Liu, Yan Ning, and Jun Fu Lu. "The Solution on Problem of Soft Soil Layer’s Collapse in Xin Kailing Tunnel and Evaluations on its Effect." Applied Mechanics and Materials 90-93 (September 2011): 2401–7. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.2401.

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This paper presents the solution on the soft soil layer’s collapse of Xin Kailing Tunnel in China based on the analysis on its causes. The effect of the solution is evaluated by site survey and finite element analysis. The results show that the geological factor mainly leads to collapse; the crucial factor of preventing the collapse from happening is to give a better description of the tunnel face, to analyze and predict conditions of wall rocks which are in front of the tunnel face in time and to evaluate precisely whether the wall rocks and supporting system are strong enough or not; effective ways to solve the collapse problem is to strengthen supporting system of the being influenced parts in the tunnel, to seal wall rocks in collapsed possibly part as well as to add supporting system in time; the minimum safety factor of the solution in this project is about 3.1 which meets official standards of the tunnel construction; the solutions on the soft soil layer’s collapse of Xin Kailing Tunnel is effective, safe and reliable.

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Sun, De'an, Daichao Sheng, and Yongfu Xu. "Collapse behaviour of unsaturated compacted soil with different initial densities." Canadian Geotechnical Journal 44, no. 6 (June 1, 2007): 673–86. http://dx.doi.org/10.1139/t07-023.

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Very few experimental data on the mechanical behaviour of unsaturated soils exists, particularly on the collapse behaviour under general stress states, because of the technical difficulties and time-consuming nature of measuring suction and deformation. This paper presents the results of a series of controlled-suction triaxial tests on the collapse behaviour of an unsaturated compacted clay with different initial dry densities and suctions. The collapse behaviour here includes deformation characteristics, such as volume changes, and hydraulic characteristics, such as saturation changes. It is found that the wetting-caused collapse mainly depends on the mean net stress and the initial density, and that the volume decrease reaches a maximum when the specimen is under the initial yielding mean net stress. It is also found that the soil-water characteristic curve in terms of suction and degree of saturation shifts upwards with increasing specimen density. The soil-water characteristic curve of a compacted soil mainly depends upon the current density, not directly upon the stress state. In addition, experimental data show that the collapse occurs mainly in an intermediate range of suction levels, which are neither very high nor very low, and that the wetting-caused volume decrease is accompanied by an increase in the degree of saturation.Key words: unsaturated soil, density, triaxial test, suction, collapse, degree of saturation.

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Choudhury, Chinumani, and Tadikonda Venkata Bharat. "Wetting-induced collapse behavior of kaolinite: influence of fabric and inundation pressure." Canadian Geotechnical Journal 55, no. 7 (July 2018): 956–67. http://dx.doi.org/10.1139/cgj-2017-0297.

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Collapsible soils are known to withstand high normal stresses without undergoing a significant volume change in an air-dry state. The soil is, however, susceptible to a large volume change upon wetting. The volumetric collapse behavior of these soils is of great engineering interest to address the problem of ground subsidence. Kaolinite was found to be a collapsible soil similar to the loess soil. The collapse mechanism in kaolinite was due to changes in particle association (fabric) with the interaction with different pore fluids. Several physicochemical parameters strongly influenced the particle association by altering the charges on the particle surfaces and edges. The collapse nature of the kaolinite was investigated with great detail in this work. Wetting-induced collapse behavior of kaolinite was studied under the influence of pore-fluid chemistry using a multi-scale approach. The influence of pH, salt concentration, and dielectric pore-fluid environment on the clay behavior was analyzed using sedimentation and collapse tests. The collapse test results were well corroborated with the sedimentation test data, scanning electron microscopy images of lyophilized specimens, and edge isoelectric point (IEPedge). The influence of inundation fluid and inundation pressure on the fabric changes and collapse potential was elucidated. The collapse potential was found to depend on the inundation pressure and pore-fluid characteristics. Maximum collapse potential was observed to be due to water inundation and minimum due to inundation with kerosene. The mechanical pressure at higher inundation pressures helped to bring the clay platelets into better face–face association during the inundation.

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Capobianco, Vittoria, Leonardo Cascini, Sabatino Cuomo, and Vito Foresta. "Wetting-induced collapse behaviour of a natural and vegetated coarse pyroclastic soil." E3S Web of Conferences 195 (2020): 03025. http://dx.doi.org/10.1051/e3sconf/202019503025.

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Unsaturated pyroclastic soils originated by Vesuvius volcano show a collapsible behaviour upon wetting with a significant reduction in volume and rearrangement of solid skeleton. The paper investigates the role played by vegetation on wetting-induced collapse behaviour (namely, collapsibility) of reconstituted unsaturated soil specimens through two series of wetting tests in a standard oedometer. The first series of tests was performed on bare soil specimens, as to resemble the site conditions. The second group of tests was conducted on the same soil previously vegetated for 20 weeks with perennial graminae species, which are frequently used as a nature-based solution for contrasting surface erosion along slopes in different geo-environmental contexts. First, an initial small vertical net stress was applied on partially saturated specimens having similar initial saturation degree, then collapse was induced by flooding the specimens with distilled water and final vertical displacements were measured. As main outcome, soil porosity is highly reduced by the growth of grass roots. Consequently, the potential wetting collapse in the rooted soils is inhibited by low values of porosity. For similar initial soil porosity, in both bare and vegetated specimens (after root growth), a further reduction of the volumetric collapse magnitude is observed.

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Junaideen, Sainulabdeen Mohamed, Leslie George Tham, and Chack Fan Lee. "Instability of Compacted Residual Soil." Geosciences 11, no. 10 (September 24, 2021): 403. http://dx.doi.org/10.3390/geosciences11100403.

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Static liquefaction of loose sands has been observed to initiate at stress ratios far less than the steady-state stress ratio. Different collapse surface concepts largely based on undrained triaxial test results have been proposed in the literature to explain the above instability phenomenon of loose sands. Studies of the instability behavior of fill material derived from residual soils remain limited. The present study investigated the instability behavior of a compacted residual soil using the conventional undrained triaxial tests and specially equipped constant shear triaxial tests. The test results were characterized in the p’: q: v space using the current state parameter with respect to the steady-state line for the residual soil. A modified collapse surface that has gradients varying with p’ and v was proposed for the loose residual soil to represent the instability states of undrained loading. Under constant shear stress conditions, the soil can mobilize stress ratios higher than those defined by the modified collapse surface. An instability surface was therefore presented for the instability states reached in static loading. Further, an alternative method of deducing the instability surface from the undrained stress paths was introduced.

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Stavi, Ilan, Tamir Rozenberg, Ashraf Al-Ashhab, Eli Argaman, and Elli Groner. "Failure and Collapse of Ancient Agricultural Stone Terraces: On-Site Effects on Soil and Vegetation." Water 10, no. 10 (October 9, 2018): 1400. http://dx.doi.org/10.3390/w10101400.

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Ancient agricultural stone terraces, dated to the Roman and Byzantine ages, are prevalent across the Negev drylands of Southern Israel. The goal of these structures was to reduce hydrological connectivity by harvesting water runoff and controlling soil erosion, thus allowing cultivation of cereals. Land abandonment and the lack of maintenance have led to the failure and collapse of many of these stone terraces. The objective of this study was to assess the effect of failure and collapse of terraces on the on-site (on-field) geo-ecosystem functioning, as determined by vegetation cover and soil quality parameters. This was achieved by studying vegetal and soil properties in shrubby vegetation patches and inter-shrub spaces of intact-terrace plots and collapsed-terrace plots, as well as in the surrounding ‘natural’ lands. Mean cover of both shrubby and herbaceous vegetation was highest in intact terraces, intermediate in ‘natural’ lands, and lowest in collapsed terraces. The overall soil quality followed the same trend as the vegetation cover. Additionally, this study shows that the anthropogenic impact on geo-ecosystem functioning can be either beneficial or detrimental. While well maintained stone terraces benefit the soil and vegetation, abandoned and unmaintained terraces may result in accelerated soil erosion and land degradation.

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Houston, Sandra, and Xiong Zhang. "Review of expansive and collapsible soil volume change models within a unified elastoplastic framework." Soils and Rocks 44, no. 3 (July 8, 2021): 1–30. http://dx.doi.org/10.28927/sr.2021.064321.

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Numerous laboratory tests on unsaturated soils revealed complex volume-change response to reduction of soil suction, resulting in early development of state surface approaches that incorporate soil expansion or collapse due to wetting under load. Nonetheless, expansive and collapsible soils are often viewed separately in research and practice, resulting in development of numerous constitutive models specific to the direction of volume change resulting from suction decrease. In addition, several elastoplastic models, developed primarily for collapse or expansion, are modified by add-on, such as multiple yield curves/surfaces, to accommodate a broader range of soil response. Current tendency to think of unsaturated soils as either expansive or collapsible (or, sometimes, stable), has likely contributed to lack of development of a unified approach to unsaturated soil volume change. In this paper, common research and practice approaches to volume change of unsaturated soils are reviewed within a simple macro-level elastoplastic framework, the Modified State Surface Approach (MSSA). The MSSA emerges as a unifying approach that accommodates complex volume change response of unsaturated soil, whether the soil exhibits collapse, expansion, or both. Suggestions are made for minor adjustments to existing constitutive models from this review, typically resulting in simplification and/or benefit to some of the most-used constitutive models for unsaturated soil volume change. In the review of practice-based approaches, the surrogate path method (SPM), an oedometer/suction-based approach, is demonstrated to be consistent with the MSSA framework, broadly applicable for use with expansive and collapsible soils, and yielding results consistent with measured field stress-path soil response.

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Quevedo, Roberto, Celso Romanel, and Deane Roehl. "Numerical modeling of unsaturated soil behavior considering different constitutive models." MATEC Web of Conferences 337 (2021): 02007. http://dx.doi.org/10.1051/matecconf/202133702007.

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Recent advances, not only in fluid flow but also in soil mechanics, have allowed the understanding and forecasting of common engineering problems such as slope stability, soil shrinkage and soil collapse. However, owing to limited access to data or more sophisticated numerical tools, the modeling of soil behavior is usually carried out considering simpler constitutive models which cannot predict some important features of unsaturated soils. This study is focused on the numerical modeling of unsaturated soils, adopting four constitutive models based on theories of elasticity and plasticity. For each model, a numerical simulation of a circular footing resting over a soil that is subject to drying and wetting processes is analyzed. Through the comparison of results, it is possible to highlight the use of more sophisticated constitutive models for unsaturated soil behavior, particularly forecasting the phenomenon of pore collapse during wetting processes.

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Smalley, Ian, and Samson Ng’ambi. "Problems with collapsible soils: Particle types and inter-particle bonding." Open Geosciences 11, no. 1 (November 16, 2019): 829–36. http://dx.doi.org/10.1515/geo-2019-0064.

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Abstract A collapsible soil is composed essentially of a packing of mineral particles and a set of interparticle bonds holding the system together. Failure requires the bond system to fail and the soil structure to collapse. A natural hazard is presented. The soil structure may collapse inwards (consolidate), as in loess failure, or it may collapse outwards (disperse, disintegrate), as in the failure of quick-clays, some collapsing sands, some silty estuarine deposits, and in wind erosion of silty soils by saltating sand grains. Generalising about bonding systems allows two types of interparticle bond to be recognized: long range bonds and short range bonds. Long range bonds are found in clay mineral systems and allow the occurrence of plasticity. They are represented by c in the standard Coulomb equation. Short range bonds are found in inactive particle systems. These are soil systems where the constituent particles do not have a significant electrical charge. A slight deformation of a short-range bonded system causes much loss of strength. It is short range bonds which tend to dominate in collapsing soil systems, although in the complex case of loess the bond failure is initially mediated by long range bonds at the interparticle contact regions. A collapse failure involves a large scale remaking of the soil structure, and thus total failure of the bonding system. Generalising again- it can be claimed that five types of particle make up engineering soils: A active clay mineral particles (the smectites), B inactive clay mineral particles (e.g. kaolinite, illite), C very small inactive primary mineral particles (close to the comminution limit in size- mostly in the quick-clays), D silt (usually quartz silt), and E sand (usually quartz sand). The nature of type D particles contributes to the collapse of loess soils, the most widespread of the collapsing soil phenomena. The nature of type C particles controls the behaviour of quick-clays. C and D systems are essentially dominated by short-range bonds.

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Cheng, X. S., G. Zheng, Y. Diao, T. M. Huang, C. H. Deng, D. Q. Nie, and Y. W. Lei. "Experimental study of the progressive collapse mechanism of excavations retained by cantilever piles." Canadian Geotechnical Journal 54, no. 4 (April 2017): 574–87. http://dx.doi.org/10.1139/cgj-2016-0284.

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An increasing number of catastrophic progressive collapses of deep excavations have occurred throughout the world. However, the research on progressive collapse mechanisms is limited. In this paper, two categories of model tests were conducted to investigate the mechanism of partial collapse (sudden failures of certain retaining piles) and progressive collapse. The model test results show that partial collapse can cause a sudden increase in the bending moments of adjacent piles via an arching effect. The load-transfer coefficients are defined to be equal to the peak increase ratios of the maximum bending moments in adjacent piles (peak moments caused by collapse over the values before the collapse). When the maximum load-transfer coefficient is larger than the bearing capacity safety factor of the piles, the partial failure will lead to progressive collapse. The influential factors of the progressive collapse mechanism, such as the partial collapse extent, excavation depth, and capping beam, were also investigated. During progressive collapse, the previous failed pile could cause new stress arching; simultaneously, the soil behind certain nearest intact piles could become loosened and destroy the arch springing of the stress arching, causing the progressive collapse to cease gradually.

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Al-Murshedi, Alaa D., Mahdi O. Karkush, and Hussein H. Karim. "Collapsibility and Shear Strength of Gypseous Soil Improved by Nano Silica Fume (NSF)." Key Engineering Materials 857 (August 2020): 292–301. http://dx.doi.org/10.4028/www.scientific.net/kem.857.292.

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The problematic soils have complex and irregular behavior such as gypseous soils, which concentrated mainly in the dry and semi-dry regions in the world. In Iraq, the gypseous soils cover about 30 to 35% of its total area in the west desert and extended to the southern parts of Iraq. The gypseous soils experience sudden collapse upon wetting. The present paper focuses on studying the effects of nano silica fume (NSF) on the collapsibility and shear strength of gypseous soil before and after soaking. Also, this study, the influence of NSF on the chemical and physical characteristics of gypseous soil have been investigated. A gypseous soil sample obtained from Al-Najaf Sea has gypsum content of 42%. The gypseous soil samples are mixed with three percentages of nano silica fume (1, 2, and 4) % calculated as ratio of the dry mass of soil to measure their influence on the geotechnical characteristics of soil samples. The collapse potential of gypseous soil is reduced with increasing the content of nano silica fume. Also, increasing the content of NSF and curing time resulted in increasing the shear strength of soil samples.

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Manoharan, N., and S. P. Dasgupta. "Collapse load computation for high-friction soil." Computers & Structures 62, no. 4 (February 1997): 681–84. http://dx.doi.org/10.1016/s0045-7949(96)00240-4.

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Basma, Adnan A., and Nabil Kallas. "Modeling soil collapse by artificial neural networks." Geotechnical and Geological Engineering 22, no. 3 (2004): 427–38. http://dx.doi.org/10.1023/b:gege.0000025044.72718.db.

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Habibagahi, G., and M. Mokhberi. "A hyperbolic model for volume change behavior of collapsible soils." Canadian Geotechnical Journal 35, no. 2 (April 1, 1998): 264–72. http://dx.doi.org/10.1139/t97-089.

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Finite element computer programs are frequently used to analyze and design embankments and similar earth structures. In most of the available computer programs, lack of a proper constitutive relationship to deal with volume change when an increase in the degree of saturation occurs, namely collapse phenomena, is a major handicap. In this paper, volume change results obtained from isotropic compression tests conducted on unsaturated compacted soil specimens are presented. Dependence of the bulk modulus of the soil on water content is investigated. Next, a hyperbolic formulation for volume change behavior of unsaturated soils taking into account variation of soil water content is presented. This hyperbolic model relates mean applied stress, volume change, and water content and represents a three-dimensional surface, the so-called "state surface". Suitability of the proposed model to predict collapse phenomena is verified by examining the model prediction against available experimental data.Key words: hyperbolic, unsaturated soil, collapse, volume change, suction pressure, bulk modulus.

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Valencia González, Yamile, Jorge Andrés Yepes-García, and Oscar Echeverri-Ramírez. "Evaluation by different methodologies of collapse potential of some residual soils in Aburrá and San Nicolás Valleys." Boletín de Ciencias de la Tierra, no. 38 (July 1, 2015): 60–64. http://dx.doi.org/10.15446/rbct.n38.49026.

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The process of precipitated variation of a soil volume when subjected to increase in stresses which withstand and/or the degree of saturation, it's also known as collapse. Collapse Potential of soils can be determined from correlations derivative of the material properties index. That's why in this work, it was evaluated using different methods the Collapse Potential of soils for ten specimens of tropical residual soils coming from five different points in Aburrá and San Nicolás Valleys, and the results were compared with the index collapse obtained using the duple-oedometer test. It was achieved to establish which of the procedures is closer to the traditional test results, and thereby obtain an approximation to the potential collapse using easy implementation methodologies with significant costs savings and rehearsal times, without loss of reliability evaluation.

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Md Nujid, Masyitah, and Mohd Raihan Taha. "Soil Plasticity Model for Analysis of Collapse Load on Layers Soil." MATEC Web of Conferences 47 (2016): 03020. http://dx.doi.org/10.1051/matecconf/20164703020.

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Bellil, Soumia, Khelifa Abbeche, and Ouassila Bahloul. "Treatment of a collapsible soil using a bentonite–cement mixture." Studia Geotechnica et Mechanica 40, no. 4 (December 31, 2018): 233–43. http://dx.doi.org/10.2478/sgem-2018-0042.

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Abstract The study of collapsible soils that are generally encountered in arid and semi-arid regions remains a major issue for geotechnical engineers. This experimental study, carried out on soils reconstituted in the laboratory, aims firstly to present a method of reducing the collapse potential to an acceptable level by treating them with different levels of bentonite–cement mixture while maintaining the water content and degree of compactness, thus reducing eventual risks for the structures implanted on these soils. Furthermore, a microscopic study using scanning electron microscopy was carried out to explore the microstructure of the soil in order to have an idea of the phenomena before and after treatment. The results show that treatment with a bentonite–cement mixture improves the geotechnical and mechanical characteristics, modifies the chemical composition of the soil, reduces the collapse potential and the consistency limits. The microstructural study and the X-ray energy dispersive spectroscopy analysis clearly illustrate an association of elementary particles in the soil aggregates, whereby the arrangement of these aggregates leads to the formation of a dense and stable material.

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Wu, Ze-Xiang, Hui Ji, Jian Han, and Chuang Yu. "Numerical modelling of granular column collapse using coupled Eulerian–Lagrangian technique with critical state soil model." Engineering Computations 36, no. 7 (August 12, 2019): 2480–504. http://dx.doi.org/10.1108/ec-08-2018-0358.

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Purpose Current modellings of granular collapse are lack of considering the effect of soil density. This paper aims to present a numerical method to analyse the collapse of granular column based on the critical-state soil mechanics. Design/methodology/approach In the proposed method, a simple critical-state based constitutive model is first adopted and implemented into a finite element code using the coupled Eulerian–Lagrangian technique for large deformation analysis. Simulations of column collapse with various aspect ratios are then conducted for a given initial soil density. The effect of aspect ratio on the final size of deposit morphology, dynamical collapse profiles and the stable region is discussed comparing to experimental results. Moreover, complementary simulations with various initial soil densities on each aspect ratio are conducted. Findings Simulations show that a lower value of initial density leads to a lower final deposit height and a longer run-out distance. The simulated evolutions of kinetic energy and collapsing profile with time by the proposed numerical approach also show clearly a soil density-dependent collapse process. Practical implications To the end, this study can improve the understanding of column collapse in different aspect ratios and soil densities, and provide a computational tool for the analysis of real scale granular flow. Originality/value The originality of this paper is proposed in a numerical approach to model granular column collapse considering the influences of aspect ratio and initial void ratio. The proposed approach is based on the finite element platform with coupled Eulerian–Lagrangian technique for large deformation analysis and implementing the critical-state based model accounting for the effect of soil density.

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Zhang, Jin Tuan, Dong Lin Meng, and Hai Xiang Wang. "The Study of Sand Hole Collapse Mechanism." Applied Mechanics and Materials 501-504 (January 2014): 434–38. http://dx.doi.org/10.4028/www.scientific.net/amm.501-504.434.

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When constructed the bored pile in sand layer, it is easily to appear the under-reaming and hole collapsed phenomenon. Then it will lead to the engineering disasters, such as hole collapsed, burying drilling and super party amount of concrete. Through the mechanics analysis of the fine sand in the hole process, we found that the mud turbulence will be broken in the drilling process which can cause the water in the hole to be turbulent fluctuation. The result of turbulent fluctuation is making the slurry wall inside and outside the test pressure difference exceeds the wall shear strength which results in the wall off block. At the end, the sand soil collapse dropping leads to the engineering disaster.

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Wang, Min, Mingshou Zhong, Yuan Long, Kai Ding, Xingbo Xie, and Liu Ying. "Study on Dynamic Strain Regularity and Influencing Factors of Shallow Buried Metal Pipe under Collapse Impact Load." Shock and Vibration 2018 (December 2, 2018): 1–11. http://dx.doi.org/10.1155/2018/8792564.

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With the combination of model experiment and numerical simulation, we explore the effect of collapse height, weight, and pipe-soil stiffness ratio on dynamic strain of shallow buried metal pipe under the collapse impact load. By analyzing the strain at different measuring points of the buried pipeline, the strain law of the buried pipeline under the collapse impact load is obtained. Based on the range analysis and variance significance analysis, it was found that the pipe-soil stiffness ratio has a more significant impact on the dynamic strain of the buried pipeline under impact compared to the collapse height and the weight. Then, the numerical simulation method was used to further analyze the effect of pipe-soil stiffness ratio on the dynamic response of buried pipelines; the following conclusions are drawn: As the stiffness ratio of pipe-soil increases, the plastic stress and strain of the buried pipeline will decrease, and influence of the pipeline by the collapse impact is slighter.

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Chen, Juan Nong, and Zhi Xin Yue. "The System of Soil Management in the Coal Mining Collapse Area." Applied Mechanics and Materials 361-363 (August 2013): 871–74. http://dx.doi.org/10.4028/www.scientific.net/amm.361-363.871.

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The environment restoring of the coal mining collapse area directly relates the region economy, the social stabilization, the ecological environment, also relates the sustainable development of mining area. And this is a serious problem for the mining area in China. In order to improve the environment of mining area, this paper analyzes the presence of collapse area in China. This paper analyzes the damages of coal mining collapse and the problems existing in the management and regulation of the collapse region. In addition to researching the way of soil management of coal mining subsidence area with Geographic Information System technology, he also exemplified the feasibility and necessity in soil management of the coal mining collapse area with Geographic Information System technology.

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Adjabi, Souhila, Mohamed Salah Nouaouria, and Cherif Betehi. "Effect of reinforcement fibers on the collapse potential of clayey sands." MATEC Web of Conferences 149 (2018): 01034. http://dx.doi.org/10.1051/matecconf/201814901034.

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The collapse of soils under wetting is a major problem in Geotechnical engineering. The erection of structures on these types of soils, located in arid and semi-arid zones, needs careful treatment of these soils. Soil reinforcement techniques have been rapidly increased during these two decades because of their effectiveness in geotechnical engineering. The aim of this experimental work is to investigate the collapsible soil behaviour in order to improve its characteristics. To achieve this goal, Polyethylene fibers, and Sisal fibers were used as Polyethylene fibers content in mass are varied from 0% (unreinforced samples) to 15%; and Sisal fibers content from 0.5% to 1%. The fiber reinforcement is combined with other processing procedures such as compaction and the addition of CPA cement to decrease the collapse potential.

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Khoshnoudian, Faramarz, Ehsan Ahmadi, Mahdi Kiani, and Mohammad Hadikhan Tehrani. "Dynamic Instability of Soil-SDOF Structure Systems under Far-Fault Earthquakes." Earthquake Spectra 31, no. 4 (November 2015): 2419–41. http://dx.doi.org/10.1193/062613eqs170m.

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A parametric study is devoted to investigating the dynamic instability of soil-structure systems under far-fault earthquakes. The superstructure and soil are simulated as a bilinear single-degree-of-freedom (SDOF) oscillator and based on the cone model concept, respectively. The results show that soil flexibility makes the system dynamically more unstable and that as the non-dimensional frequency increases, the collapse strength-reduction factor highly decreases. Moreover, increasing the aspect ratio leads to a lower collapse strength-reduction factor. However, its effect is found to be negligible. The effects of vibration period and post-yield slope on the collapse strength-reduction factor are the same as on the fixed-base condition. Additionally, comparison of collapse strength-reduction factors resulting from exact time history analyses with those proposed in FEMA 440 for the fixed-base condition shows a great underestimation with errors larger than 20% at approximately all cases and 60% at extreme cases. Finally, a formulation is calibrated using nonlinear regression analysis in order to estimate collapse strength-reduction factors of soil-structure systems.

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Mansour, Z. M., Z. Chik, and M. R. Taha. "On the Procedures of Soil Collapse Potential Evaluation." Journal of Applied Sciences 8, no. 23 (November 15, 2008): 4434–39. http://dx.doi.org/10.3923/jas.2008.4434.4439.

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Kamei, Takeshi, and Masao Enomoto. "Wetting-Induced Collapse Behaviour of Compacted Silty Soil." Doboku Gakkai Ronbunshu, no. 505 (1994): 97–103. http://dx.doi.org/10.2208/jscej.1994.505_97.

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Lawton, Evert C., Richard J. Fragaszy, and Mark D. Hetherington. "Review of Wetting‐Induced Collapse in Compacted Soil." Journal of Geotechnical Engineering 118, no. 9 (September 1992): 1376–94. http://dx.doi.org/10.1061/(asce)0733-9410(1992)118:9(1376).

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Liu, S. H., and D. A. Sun. "Simulating the collapse of unsaturated soil by DEM." International Journal for Numerical and Analytical Methods in Geomechanics 26, no. 6 (2002): 633–46. http://dx.doi.org/10.1002/nag.215.

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Michalowski, Radoslaw L. "Expanding collapse in partially submerged granular soil slopes." Canadian Geotechnical Journal 46, no. 12 (December 2009): 1371–78. http://dx.doi.org/10.1139/t09-064.

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The traditional approach to stability analysis of granular slopes leads to the safety factor that is associated with a planar failure surface approaching the slope face, whether the slope is “dry” or submerged. However, for partially submerged slopes, a more critical, nonplanar failure surface can be formed. A family of geometrically similar surfaces can be found that is characterized by the same safety factor. If the safety factor drops down to unity and the slope becomes unstable, then a mechanism of any size can form. Alternatively, the failure may start at some small region and then the volume of the mechanism of failure can expand, giving rise to a progressive failure of a different kind that is typically associated with slopes. This progression has the character of a “disturbance” or a shock-like kinematic discontinuity propagating into the soil at rest. A quantitative analysis is presented and it is demonstrated that the soil dilates while the mechanism expands, leaving the slope weakened and susceptible to a deep failure. This is a plausible mode of failure of partially submerged slopes, the type that is most likely responsible for large subaqueous landslides, and is similar to the well-documented instability propagation in “quick clay.”

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Momeni, Mehdi, Ali Shafiee, Mojtaba Heidari, Mohammad Kazem Jafari, and Mohammad Reza Mahdavifar. "Evaluation of soil collapse potential in regional scale." Natural Hazards 64, no. 1 (June 21, 2012): 459–79. http://dx.doi.org/10.1007/s11069-012-0252-z.

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Saffari, Pooya, Wen Nie, Mohd Jamaludin Md Noor, Afshin Asadi, Jinquan Liu, and Xiaolong Zhang. "Collapse behavior of unsaturated remolded granitic residual soil." Bulletin of Engineering Geology and the Environment 79, no. 7 (April 3, 2020): 3857–68. http://dx.doi.org/10.1007/s10064-020-01789-9.

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Najemalden, Ahmed M., Salah W. Ibrahim, and Mahmoud D. Ahmed. "Effect of Coefficient of Variation on the Reliability of Collapse Potential's Equation Predicted by ANNs." Key Engineering Materials 857 (August 2020): 195–202. http://dx.doi.org/10.4028/www.scientific.net/kem.857.195.

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In this paper, the Reliability Analysis with utilizing a Monte Carlo simulation (MCS) process was conducted on the equation of the collapse potential predicted by ANN to study its reliability when utilized in a situation of soil that has uncertainty in its properties. The prediction equation utilized in this study was developed previously by the authors. The probabilities of failure were then plotted against a range of uncertainties expressed in terms of coefficient of variation. As a result of reliability analysis, it was found that the collapse potential equation showed a high degree of reliability in case of uncertainty in gypseous sandy soil properties within the specified coefficient of variation (COV) for each property. When the COV ranges (0-100) for each soil properties under study, it was found also that the collapse potential equation is very well in predicting the collapse potential of gypseous sandy soils for all values of the COV lies between (0-100) % for initial water content and degree of saturation, and for values of the COV not exceed 11%, 19% for the initial dry unit weight and specific gravity respectively, as well as for the values of the COV not exceed 80%, 97% for the initial voids ratio and gypsum content respectively.

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Fagundes, Luiza P., Jhaber D. Yacoub, Andrey C. Lima, Flávia R. Nakatsuchi, José A. Lollo, Jorge L. Akasaki, and Mauro M. Tashima. "Improvement of Collapsible Soil Behavior of a Lateritic Soil Using Rice Husk Ash." Key Engineering Materials 668 (October 2015): 290–96. http://dx.doi.org/10.4028/www.scientific.net/kem.668.290.

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Great areas of Brazil present lateritic soils, such as the northeast and the south. Some of these soils have, as main characteristic, instable structures that can present considerable volumetric deformation in the presence of water. This behavior, also named collapse, is responsible for several problems on the building construction such as cracks and fractures that can damage the safety of structures. The aim of this paper is to assess the possibility of improvement of collapsible behavior of a lateritic soil using rice husk ash (RHA). A previous characterization of soil and RHA was performed in order to assess the combined effect of soil/RHA. The results are so promising, showing a new alternative to reduce the collapsible behavior of soils using an environmental friendly technology.

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Abbas, Jawdat, and Hamad Al-Luhaibi. "Influence of Iron Furnaces Slag on Collapsibility and Shear Strength of Gypseous Soil." No.1 27, no. 1 (March 15, 2020): 65–71. http://dx.doi.org/10.25130/tjes.27.1.09.

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Gypseous soil is one of the soils that suffer from problems and suffers from a reduction of shear strength and collapse when exposed to water immersion or water filtration in it. Many researchers have tried to solve these problems in different ways and by using many materials as additives to improve the performance and efficiency of this soil. In this research, the behavior of soil with a high content of gypsum (61.49%) is examined, using iron slag which is a by-product of the iron making process in melting furnaces, used as an additive in proportions (2, 4, 6, 8, 10., 12) %, by dry mixing method with soil. Tests are carried out to determine the effect of this substance on the shear strength parameters. The effect of water immersion on soil cohesion (c) is reduced until it reaches (c) in the case of immersion a value very close to the value in the dry state at slag ratio (10) %. This is the optimum ratio of slag to improve the value of (c). Whereas for the value of (ø), with the increase of the slag rate for both wet and dry cases, the value of (ø) increases, where (ø) reaches the highest value at; the slag rate (10) % for the dry state, and the slag rate (8) % for the soaked case. Whereas for the collapse potential (Cp), adding the slag reduces the value of the soil collapse potential (Cp), from (10.6) to the soil without additives until (0.95) for the slag rate (12) %. Then the soil becomes problematic soil.

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Journal articles on the topic 'Collapse of the soil'

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