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Jianhua Yin - One of the best experts on this subject based on the ideXlab platform.
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influence of Matric Suction on nonlinear time dependent compression behavior of a granular fill material
Acta Geotechnica, 2020Co-Authors: Wen Bo Chen, Lalit Borana, Kai Liu, Wei Qiang Feng, Jianhua YinAbstract:The site formation for the construction of a new airport in a mountainous region is typically performed by cutting and filling a hill section. The fill materials are subjected to seasonal changes and large variations in water content. The water content change renders the fill material to be characterized as unsaturated or saturated. This study aims to investigate the influence of Matric Suction on the time-dependent compression behavior of one local soil as a fill material for the construction of a new runway of an airport in Chongqing city, a mountainous region in China. A series of unsaturated drained triaxial tests were conducted on this coarse-grained soil to obtain the relationship between the effective stress parameter, χ, and the Matric Suction. Subsequently, multistaged compression tests were performed on this soil using a newly designed Suction-controlled oedometer apparatus. The influence of Suction on the time-dependent compression behavior of the fill material is emphasized. The results indicate that the Matric Suction can increase the compression stiffness, and that the unloading–reloading index varies nonlinearly with Suction. A linear relationship between the time-dependent compression coefficient and normalized effective vertical loading is established. The linear relationship is subsequently used to predict the time-dependent compression coefficient to describe the time-dependent behavior of the fill under unsaturated conditions. Further, a nonlinear function based on the work of Yin (Geotechnique 49(5):699–707, 1999) is adopted to describe the development of time-dependent compression. The results indicate that the prediction obtained from the two newly proposed methods are promising, and can predict the nonlinear time-dependent compression behavior of this coarse-grained soil.
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influence of Matric Suction and counterface roughness on shearing behavior of completely decomposed granitic soil and steel interface
Indian Geotechnical Journal, 2017Co-Authors: Lalit Borana, Jianhua Yin, D N Singh, Sanjay Kumar ShuklaAbstract:The interface can be defined as the zone in which the transfer of stresses occurs between soil and structure. The behavior interface is significantly influenced by stress state variables. In this paper, the influence of Matric Suction and counterface roughness on the interface shearing behavior was examined by conducting a series of Suction controlled direct shear test on the interface formed between completely decomposed granite soil and steel specimens. Experimental tests were performed on two different types of soil–steel interfaces under different stress state variables. Test results show that Matric Suction has a significant influence on the interface shear behavior. The counterface roughness influences the dilative-contractive behavior of the interface. The critical interface shear strength at specific counterface roughness and net normal stress is controlled by the Matric Suction. The experimental results are compared with an analytical model that considers the influence of Suction and dilation on apparent interface friction angle. The analytical model works reasonably well for predicting the unsaturated soil–steel interface shear strength under different stress state variables.
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dilatancy and strength of an unsaturated soil cement interface in direct shear tests
International Journal of Geomechanics, 2015Co-Authors: Akhtar Hossain, Jianhua YinAbstract:AbstractThe dilatancy of a soil is significantly influenced by Matric Suction, and it affects the apparent friction angle and shear strength of the soil. To examine the influence of dilatancy on interface behavior, a series of direct shear box tests are conducted on a compacted completely decomposed granite (CDG) soil–grout interface in a cast in situ condition under different Matric Suctions and net normal stresses. The test results indicate that Matric Suction and net normal stress have significant influence on the hardening-softening and dilatancy of the soil–cement grout interface. The failure envelopes for different Matric Suctions are observed as linear. The apparent interface friction angle and adhesion intercept increase with Matric Suction. The Suction envelope is found to be nonlinear as the δb-angle decreases with Matric Suction. A modified model is proposed to consider the influence of dilatancy on the apparent interface friction angle and hence on the interface shear strength. Experimental sh...
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behavior of a compacted completely decomposed granite soil from Suction controlled direct shear tests
Journal of Geotechnical and Geoenvironmental Engineering, 2010Co-Authors: Md Akhtar Hossain, Jianhua YinAbstract:A series of single-staged consolidated drained direct shear tests are carried out on recompacted completely decomposed granite (CDG) soil—a typical residual soil in Hong Kong, under different Matric Suctions and net normal stresses. Matric Suction is controlled by applying air pressure in the pressure chamber and water pressure at the bottom of the high air-entry ceramic disk. The experimental results show that the contribution of Suction to shear strength is significant. Shear strength of CDG soil increases with the increase of Matric Suction. Net normal stress has a remarkable influence on the shear strength of unsaturated CDG soil. The increase in shear strength due to an increase in Matric Suction (Suction envelope) is observed as nonlinear i.e., ϕb value varies with Matric Suction. No soil dilatancy is observed for zero Matric Suction (saturated case) but as the Suction value is increased, higher soil dilatancy is obvious in lower net normal stresses. The rate of increase of soil dilatancy is greater...
Shu Rong Yang - One of the best experts on this subject based on the ideXlab platform.
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Suction controlled laboratory test on resilient modulus of unsaturated compacted subgrade soils
Journal of Geotechnical and Geoenvironmental Engineering, 2008Co-Authors: Shu Rong Yang, Hornda Lin, Johnson H S Kung, Wei Hsing HuangAbstract:Conventionally, the resilient modulus test is conducted in the laboratory under different moisture content in which Matric Suction is unknown during the test. To investigate the influence of the Matric Suction on the resilient modulus, this study integrated the Suction-controlled testing system and developed a modified testing procedure for the resilient modulus test of unsaturated subgrade soils. Based on the axis-translation technique, two cohesive soils were tested to investigate the effect of Matric Suction on resilient modulus. In the modified testing procedure, in order to fulfill the equilibrium in Matric Suction, the number of load cycles at each loading sequence of the resilient modulus test (AASHTO T 292-91) needs to be increased significantly. Experimental data indicate that Matric Suctions measured in the specimen after consolidation and resilient modulus tests are consistent with the Matric Suctions deduced from the soil-water characteristic curve corresponding to the same moisture content. In general, the resilient modulus obtained by the Suction-controlled resilient modulus test appears to be reasonable. The trends of resilient modulus obtained by the Suction-controlled resilient modulus test are consistent with those obtained by the conventional resilient modulus test. However, the Suction-controlled resilient modulus test provides better insights that can help in interpreting the test results.
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shear wave velocity and Suction of unsaturated soil using bender element and filter paper method
2008Co-Authors: Shu Rong Yang, Hornda Lin, Johnson Hsiang, Sheng Kung, Jrying LiaoAbstract:A study was conducted to determine the dynamic properties of compacted clayey soil with Matric Suction measurement. The effects of Matric Suction of unsaturated residual lateritic soil on small-strain shear wave velocity and small-strain shear modulus were investigated. Soil specimens were compacted at optimum moisture content, wetted to various moisture contents, then, tested for small-strain shear wave velocity and Matric Suction using the bender element and the filter paper method, respectively. Test results demonstrated that the small-strain shear wave velocity and small-strain shear modulus decrease with increasing moisture content and decreasing Matric Suction. Test results also indicated that when the degree of saturation changes slightly, although Matric Suction changes greatly, soil can be regarded as to have a nearly consistent soil skeleton. Hence, reductions of shear wave velocity and shear modulus are limited.
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variation of resilient modulus with soil Suction for compacted subgrade soils
Transportation Research Record, 2005Co-Authors: Shu Rong Yang, Wei Hsing Huang, Yutsung TaiAbstract:The variations of resilient modulus with the postconstruction moisture content and soil Suction for cohesive subgrade soils were evaluated. In particular, the effects of relative compaction of the subgrade on the Suction and resilient modulus were investigated. To simulate subgrade soils at in-service conditions, soil specimens were compacted at various relative compactions and optimum moisture content and then saturated to equilibrium moisture content to test for resilient modulus and soil Suction. The filter paper method was used to measure the total and Matric Suctions of two cohesive soils. Test findings demonstrated that resilient modulus correlated better with the Matric Suction than with total Suction. Matric Suction was found to be a key parameter for predicting the resilient modulus of cohesive subgrade soils. A prediction model incorporating deviator stress and Matric Suction for subgrade soil resilient modulus was established.
Gerald A. Miller - One of the best experts on this subject based on the ideXlab platform.
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influence of Matric Suction on geotextile reinforcement marginal soil interface strength
Geotextiles and Geomembranes, 2014Co-Authors: Danial Esmaili, Kianoosh Hatami, Gerald A. MillerAbstract:Abstract This paper presents descriptions and results of multi-scale pullout and interface shear tests on a woven polypropylene (PP) geotextile reinforcement material in a marginal quality soil. A main objective of these tests was to develop a moisture reduction factor (MRF) for the pullout resistance equation in the currently available design guidelines. The tests were carried out at different overburden pressure and gravimetric water content (GWC) values. The differences in the soil-geotextile interface strength among the cases with different GWC values were used to determine the corresponding MRF values. Results of the study indicate that the reinforcement interface strength and pullout resistance could decrease significantly as a result of the loss in the Matric Suction (e.g. by 42% between the cases of 2% dry and 2% wet of the soil optimum moisture content). It is concluded that wetting of the soil-geotextile interface during construction or service life of a reinforced soil structure can measurably reduce the interface strength and pullout resistance of the geotextile reinforcement which needs to be accounted for in design. Results of the study will be also useful to estimate the difference in the pullout capacity of geotextile reinforcement in a marginal soil when placed at different GWC values during construction. The methodology described in the paper could be used to expand the database of MRF results to include a wider range of soil types and geotextile reinforcement for practical applications.
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influence of gravimetric water content on geotextile reinforcement pullout resistance in mse walls with marginal quality soils
2013Co-Authors: Kianoosh Hatami, Danial Esmaili, Jaime E Granados, Gerald A. MillerAbstract:Pullout capacity of geotextile reinforcement is an important consideration in the internal stability analysis of reinforced soil structures, especially those constructed with marginal soils. Precipitation, ground water infiltration and seasonal variations of moisture content during the construction process or service life of the structure could result in significant reductions in the Matric Suction, leading to a reduction in the soil-geotextile interface strength. Consequently, the reinforced soil structure may experience unacceptable deformations or even failure during its construction or post-construction periods. It should be noted that the loss of Matric Suction in the soil influences both the shear strength of the soil and the soil-reinforcement interface. However, the focus of this study is merely on the latter. In this study, a series of pullout and interface shear tests were carried out to measure the pullout resistance of a reinforcement geotextile in a marginal soil which was compacted at different gravimetric water contents (GWC). The marginal soil was selected to meet the limiting requirements of the National Concrete Masonry Association (NCMA) guidelines for segmental retaining walls with respect to the fines content, gradation and plasticity. The range of GWC values investigated varied from dry to wet side of the soil Optimum Moisture Content (OMC). The Matric Suction in the soil was measured in order to evaluate its influence on the soilreinforcement interface shear strength. A Moisture Reduction Factor (MRF) is proposed to account for the reduction in the soil-geotextile interface strength as a result of the loss in Matric Suction.
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shear strength of unsaturated soil interfaces
Canadian Geotechnical Journal, 2009Co-Authors: Tariq Hamidt B B Hamid, Gerald A. MillerAbstract:Unsaturated soil interfaces exist where unsaturated soil is in contact with structures such as foundations, retaining walls, and buried pipes. The unsaturated soil interface can be defined as a layer of unsaturated soil through which stresses are transferred from soil to structure and vice versa. In this paper, the shearing behavior of unsaturated soil interfaces is examined using results of interface direct shear tests conducted on a low-plasticity fine-grained soil. A conventional direct shear test device was modified to conduct direct shear interface tests using Matric Suction control. Further, the results were used to define failure envelopes for unsaturated soil interfaces having smooth and rough counterfaces. Results of this study indicate that Matric Suction contributes to the peak shear strength of unsaturated interfaces; however, postpeak shear strength did not appear to vary with changes in Matric Suction. Variations in net normal stress affected both peak and postpeak shear strength. Failure en...
Yutsung Tai - One of the best experts on this subject based on the ideXlab platform.
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variation of resilient modulus with soil Suction for compacted subgrade soils
Transportation Research Record, 2005Co-Authors: Shu Rong Yang, Wei Hsing Huang, Yutsung TaiAbstract:The variations of resilient modulus with the postconstruction moisture content and soil Suction for cohesive subgrade soils were evaluated. In particular, the effects of relative compaction of the subgrade on the Suction and resilient modulus were investigated. To simulate subgrade soils at in-service conditions, soil specimens were compacted at various relative compactions and optimum moisture content and then saturated to equilibrium moisture content to test for resilient modulus and soil Suction. The filter paper method was used to measure the total and Matric Suctions of two cohesive soils. Test findings demonstrated that resilient modulus correlated better with the Matric Suction than with total Suction. Matric Suction was found to be a key parameter for predicting the resilient modulus of cohesive subgrade soils. A prediction model incorporating deviator stress and Matric Suction for subgrade soil resilient modulus was established.
Md Akhtar Hossain - One of the best experts on this subject based on the ideXlab platform.
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dilatancy and strength of an unsaturated soil cement interface in direct shear tests
International Journal of Geomechanics, 2015Co-Authors: Md Akhtar HossainAbstract:AbstractThe dilatancy of a soil is significantly influenced by Matric Suction, and it affects the apparent friction angle and shear strength of the soil. To examine the influence of dilatancy on interface behavior, a series of direct shear box tests are conducted on a compacted completely decomposed granite (CDG) soil–grout interface in a cast in situ condition under different Matric Suctions and net normal stresses. The test results indicate that Matric Suction and net normal stress have significant influence on the hardening-softening and dilatancy of the soil–cement grout interface. The failure envelopes for different Matric Suctions are observed as linear. The apparent interface friction angle and adhesion intercept increase with Matric Suction. The Suction envelope is found to be nonlinear as the δb-angle decreases with Matric Suction. A modified model is proposed to consider the influence of dilatancy on the apparent interface friction angle and hence on the interface shear strength. Experimental sh...
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shear strength and dilative characteristics of an unsaturated compacted completely decomposed granite soil
Canadian Geotechnical Journal, 2010Co-Authors: Md Akhtar HossainAbstract:Shear strength and dilative characteristics of a re-compacted completely decomposed granite (CDG) soil are studied by performing a series of single-stage consolidated drained direct shear tests under different Matric Suctions and net normal stresses. The axis-translation technique is applied to control the pore-water and pore-air pressures. A soil-water retention curve (SWRC) is obtained for the CDG soil from the equilibrium water content corresponding to each applied Matric Suction value for zero net normal stress using a modified direct shear apparatus. Shear strength increases with Matric Suction and net normal stress, and the failure envelope is observed to be linear. The apparent angle of internal friction and cohesion intercept increase with Matric Suction. A greater dilation angle is found at higher Suctions with lower net normal stresses, while lower or zero dilation angles are observed under higher net normal stresses with lower Suctions, also at a saturated condition. Experimental shear strength...
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behavior of a compacted completely decomposed granite soil from Suction controlled direct shear tests
Journal of Geotechnical and Geoenvironmental Engineering, 2010Co-Authors: Md Akhtar Hossain, Jianhua YinAbstract:A series of single-staged consolidated drained direct shear tests are carried out on recompacted completely decomposed granite (CDG) soil—a typical residual soil in Hong Kong, under different Matric Suctions and net normal stresses. Matric Suction is controlled by applying air pressure in the pressure chamber and water pressure at the bottom of the high air-entry ceramic disk. The experimental results show that the contribution of Suction to shear strength is significant. Shear strength of CDG soil increases with the increase of Matric Suction. Net normal stress has a remarkable influence on the shear strength of unsaturated CDG soil. The increase in shear strength due to an increase in Matric Suction (Suction envelope) is observed as nonlinear i.e., ϕb value varies with Matric Suction. No soil dilatancy is observed for zero Matric Suction (saturated case) but as the Suction value is increased, higher soil dilatancy is obvious in lower net normal stresses. The rate of increase of soil dilatancy is greater...