Relationship between the matric suction and the shear strength in unsaturated soil

Idris, Ahmad; Fattah, Mohammed Y.; Mekkiyah, Haider M.

doi:10.1016/j.cscm.2020.e00441

Cited by 24 publications

(7 citation statements)

References 15 publications

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“…In the case of expansive soils, these changes in moisture content mostly occur due to seasonal fluctuations. As a consequence, the expansive soil experiences either settlement or ground heave due to wetting and drying [1][2][3][4], and as a result of increased moisture content induced by water infiltration, the shear strength of unsaturated soil begins to decrease as the negative pore water pressure increases, which is one of the cause of slope instability [5][6][7]. The investigation of the impact of moisture content fluctuations caused by infiltration on the mechanical properties of unsaturated soil and its implications for the stability of structural foundations has become a prominent area of interest in civil and geomechanical research [8][9][10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Simulation Study of Water Infiltration Impact on Soil-Pile Interaction in Expansive Soil

Awadalseed,

Zhang,

et al. 2024

Geofluids

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A laboratory model of a single pile embedded in Nanyang expansive soil and subjected to water infiltration is applied in this study to examine the interaction between the expansive soil and pile foundation upon water infiltration. The soil matric suction decreases as a result of the rising soil-water content. The amount of soil ground heave reaches its peak of 10.7 mm after 200 hours of water infiltration. As matric suction decreases, pile shaft friction also declines, which causes more of the load at the pile head to be carried by the pile base resulting in more pile settlements. A new numerical simulation method is provided to simulate this issue by coupling the subsurface flow, soil deformation, and hygroscopic swelling to investigate the expansive soil-pile response upon water infiltration. From the numerical simulation model, hygroscopic strain arises as a result of elevated moisture levels resulting from the entry of water, and due to ground heave and the mobilization of lateral soil swelling, the shear stress at the interface between the soil and the pile gradually increases over time. It reaches its maximum value of 4420 Pa at upper depths around 200 hours after the infiltration. The comparison between the lab model testing data and the numerical model results demonstrates a good level of concurrence.

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Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Simulation Study of Water Infiltration Impact on Soil-Pile Interaction in Expansive Soil

Awadalseed,

Zhang,

et al. 2024

Geofluids

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“…The soil-water retention curve (SWRC), defines the relationship between soil suction and its water content [10][11][12][13]. The creation SWRCs enable the geotechnical experts to characterize the suction behavior of unsaturated soil and effectively address the diverse geotechnical engineering challenges related to slope stability, foundation bearing capacity, seepage, permeability, and shear strength properties of unsaturated soil [14][15][16][17]. While significant advances have been made in the field of unsaturated soil mechanics in recent years, there is still a notable gap in our understanding of the unsaturated water retention behavior of cementitious stabilized soil, especially in gypseous soil.…”

Section: Introductionmentioning

confidence: 99%

Effects of Cement Treatment on Water Retention Behavior and Collapse Potential of Gypseous Soils: Experimental Investigation and Prediction Models

Abdulameer AlNaddaf,

Kouzegaran,

Fattah

et al. 2024

Advances in Civil Engineering

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Gypseous soil poses a significant challenge in geotechnical engineering due to its susceptibility to collapse under saturation. This type of soil covers approximately 33% of regions in Iraq, primarily in unsaturated conditions. This study focuses on two types of gypseous soils: one with moderate gypsum content from Karbala city (G1) and the other with high-gypsum content from Tikrit city (G2), to investigate the effects of cement treatment on their water retention behavior and potential for reducing collapse. Different percentages of cement were mixed with both soils to determine the optimum soil–cement mixture for reducing collapse potential (CP) through single oedometer tests. The water retention characteristics and water retention behavior of samples with varying gypsum content and different levels of cement treatment were examined and compared using a controlled-suction oedometer. The soil–water retention curve (SWRC) of these natural and treated gypseous soils was also investigated and compared in both wetting and drying paths. Additionally, multiple pedotransfer functions (PTFs) were assessed to identify or adapt prediction equation(s) for the SWRC of gypseous soil both with and without cement treatment with acceptable accuracy. The results show that adding cement can decrease the CP of gypseous soils; it also affects their SWRC significantly. By making some simple modifications, the PTFs demonstrate acceptable estimations for the water retention curve of both natural and cement-treated gypseous soils.

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“…Chen et al [7,8] indicated that the in situ stress state of natural soil is usually inherently anisotropic, that is to say, the static lateral pressure coefficient K 0 ≠ 1 in the actual stress state of soil. Fattah et al [9][10][11][12] studied the shear strength properties for unsaturated soil with different matric suction values, and it is concluded that the matric suction is considered an important contributor to unsaturated shear strength properties. Wang [13] and Wen et al [5] derived the critical edge load of soft soil foundation with hard crust based on Mohr-Coulomb criterion, the results take no account of intermediate principal stress, and the assumption K 0 = 1 is inconsistent with the actual stress state of soil.…”

Section: Introductionmentioning

confidence: 99%

Triple-Shear Unified Solution for Bearing Capacity of Unsaturated Soft Soil Foundations with Hard Crust

Cao

Jun-hai

et al. 2022

Geofluids

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The bearing capacity of unsaturated soft soil foundations is affected by natural or artificial hard crust, due to the stress diffusion and closure effect. Based on the triple-shear unified solution of shear strength for unsaturated soil, the analytical solutions of critical edge load and critical load of unsaturated soft soil with hard crust are derived with the consideration of the lateral pressure coefficient K 0 ≠ 1 . The formulas are degraded and compared. Meanwhile, the influences of stress diffusion, increased load, matric suction, intermediate principal, and lateral pressure coefficient are conducted on the bearing capacity of unsaturated soft soil foundations with hard crust. The results show that the critical edge load and critical load increased, and the stress diffusion coefficient decreased with the increase of the ratio of elastic modulus between hard crust and soft soil. The bearing capacity of soft soil foundation increased with the consideration of the stress diffusion and closure effect of hard crust. The effect of matric suction is remarkable, and the critical edge load and critical load linearly increase with the increase of low matric suction and variate with the dual influence of high matric suction. The bearing capacity of unsaturated soft soil foundation is obviously higher than that of saturated soil. The critical edge load and critical load increased with the increase of intermediate principal stress and lateral pressure coefficient. The triple-shear unified solution for bearing capacity of unsaturated soft soil foundation with hard crust contains different solutions under various working conditions, which has important theoretical significance and widely engineering application.

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Relationship between the matric suction and the shear strength in unsaturated soil

Cited by 24 publications

References 15 publications

Experimental and Numerical Simulation Study of Water Infiltration Impact on Soil-Pile Interaction in Expansive Soil

Experimental and Numerical Simulation Study of Water Infiltration Impact on Soil-Pile Interaction in Expansive Soil

Effects of Cement Treatment on Water Retention Behavior and Collapse Potential of Gypseous Soils: Experimental Investigation and Prediction Models

Triple-Shear Unified Solution for Bearing Capacity of Unsaturated Soft Soil Foundations with Hard Crust

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