Foundation bearing capacity estimation on unsaturated soil slope under transient flow condition using slip line method

Tan, Mengxi; Vanapalli, Sai K.

doi:10.1016/j.compgeo.2022.104804

Cited by 13 publications

(6 citation statements)

References 65 publications

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“…As the slope angle increases, less stress concentration is mobilized near the footing than the case when the flat ground is present, and the plastic deformations occur. For various slope inclination, the predominant failure was observed to be the slope failure [12,15] The decrease in bearing capacity also depends on the footing distance. With an increase in slope angle, bearing capacity decrease when the footing lies near the crest of slope.…”

Section: Resultsmentioning

confidence: 99%

“…But most of these studies considered the behaviour of footings on saturated soil slopes [11]. Only a few studies like [2,12] considered the case of bearing capacity of footings on unsaturated soil slopes. However, the constitutive model used for representing the stress-strain, collapse behaviour of footings on unsaturated slopes was usually the traditional Mohr-Columb model which presents several limitations for predicting the collapse behaviour of unsaturated soils.…”

Section: Introductionmentioning

confidence: 99%

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Bearing capacity of shallow footing on an unsaturated embankment upon infiltration

Showkat

Babu

2023

E3S Web of Conf.

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Due to rapid urbanization and population growth, construction activities have been increased on slopes of unsaturated hilly regions. Thus, constructing shallow footings on these slopes is a common method for supporting infrastructure construction. The main factor causing instability of these unsaturated slopes is the loss of suction upon infiltration resulting in footing failures. Thus, in this study, a shallow footing restingon an unsaturated embankment modelled using Barcelona basic model (BBM) has been numerically analysed to investigate the influence of various factors affecting the bearing capacity upon infiltration. The influence of various critical design parameters, like the distance from the crest of the slope and water table positions, slope angle, and infiltration rate, has been studied comprehensively. As the footing distance increases from the crest (setback distance), soil provides higher bearing capacity upon infiltration due to the confinement. Moreover, it is noticed that the bearing capacity reduces monotonically as the water table rises above the toe, thus depicting the Prandtl-type of failure. Further, as the slope angle increases, bearing capacity decreases at various footing distances upon infiltration. The effect of infiltration rate on bearing capacity of footings depends on the air entry value of the soil. As the air-entry value increases, bearing capacity reduces drastically upon infiltration. This approach helps the design engineers consider these factors while constructing footings on unsaturated slopes.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Bearing capacity of shallow footing on an unsaturated embankment upon infiltration

Showkat

Babu

2023

E3S Web of Conf.

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“…Addressing these phenomena is inherently challenging due to their pronounced non-linearity. Several studies [17][18][19][20][21][22][23][24][25] have modeled variations in shear strength due to moisture fluctuations. However, none of these studies have analytically incorporated more complex factors such as variations in the initial void ratio.…”

Section: Introductionmentioning

confidence: 99%

Analytical Modeling of Unsaturated Soil Shear Strength during Water Infiltration for Different Initial Void Ratios

Santos,

Sousa,

Cavalcante

2024

Sustainability

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Unsaturated soil mechanics, when applied to determine the soil shear strength, are crucial for accurately evaluating the safety of geotechnical structures affected by seasonal moisture variations. Over the past decades, multiple models have been formulated to predict the behavior of unsaturated soils in terms of water flow and shear strength individually. Building upon these foundational studies, this research introduces a model that couples an analytical solution for one-dimensional water infiltration with an unsaturated shear strength model. This model further incorporates the impact of void ratio fluctuations on soil properties and state variables related to shear strength. A parametric analysis is conducted to evaluate the effects of the initial void ratio on a representative soil profile during a water infiltration event. The model presented in this paper integrates various concepts from the field of unsaturated soil mechanics and is applicable to any homogeneous soil where expansion/collapse effects are negligible. It demonstrates how shear strength might be underestimated when using a saturated soil approach. Conversely, it may also lead to an overestimation of safety conditions if the soil approaches a saturated or dry state. The proposed model offers a more accurate prediction of unsaturated soil shear strength. It is useful for determining transient safety factors in geotechnical structures. Furthermore, when combined with field-installed instrument monitoring, this model contributes significantly to the functionality, safety, cost-effectiveness, and sustainability of geotechnical structures and projects.

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“…Therefore, research on the behavior of unsaturated soils has been prioritized over the last ten years. In the literature, experimental studies have been conducted under both drained and undrained conditions [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. In general, research in this area has aimed to improve understanding of the mechanical behavior of unsaturated soils and to develop appropriate methods for assessing the bearing capacity of unsaturated soils.…”

Section: Introductionmentioning

confidence: 99%

Bearing Capacity of Shallow Foundations on Unsaturated Silty Soils

Yılmazoğlu

Özocak

2023

Applied Sciences

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In general, the ultimate bearing capacity (UBC) of shallow foundations on unsaturated soils is characterized by the conventional shear strength (SS) parameters in which saturated theories are applied. However, in this case, it is clear that the foundations designed using the obtained values from the saturated cases not be economical. In recent years, procedures have been developed to estimate the UBC of foundations on unsaturated soils, that take into account drained and undrained loading conditions. However, these studies generally concentrate on sandy soils. The validity of the results proposed in the literature should be tested for other soils. Therefore, this paper includes a conventional direct shear box (DSB) test to determine the unsaturated SS of statically compacted silty soil, and a series of model tests were performed to determine the foundation’s UBC. In the experimental model setup, the UBC values of different types and sizes of model foundations on silty soil layers with a different soil saturation degrees (SSDs)/matric suctions (MSs) and different void ratio values were measured. In addition, the soil-water characteristic curves (SWCCs) and SS parameters of unsaturated silt were obtained. Using the experimental results, a new equation is proposed for the characterization of the UBC of shallow foundations on unsaturated silty soils. Using this equation, the UBC of unsaturated soils can be determined based on the results of unconfined compressive strength tests (UC) measured on unsaturated soil samples and based on the degree of saturation and the fitting parameter. The results indicate that the measured bearing capacity values obtained via the model footing test, shows a good consistency with those obtained by the proposed equation.

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Foundation bearing capacity estimation on unsaturated soil slope under transient flow condition using slip line method

Cited by 13 publications

References 65 publications

Bearing capacity of shallow footing on an unsaturated embankment upon infiltration

Bearing capacity of shallow footing on an unsaturated embankment upon infiltration

Analytical Modeling of Unsaturated Soil Shear Strength during Water Infiltration for Different Initial Void Ratios

Bearing Capacity of Shallow Foundations on Unsaturated Silty Soils

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