Tiered geosynthetic-reinforced soil (GRS) walls in transportation engineering are often applied in high-retaining soil structures and are typically subjected to traffic cyclic loading. However, there has been limited research on the dynamic performance of tiered GRS walls. Three reduced-scale model walls were conducted to investigate the dynamic performances of two-tiered GRS walls with different strip footing locations (d/H) under cyclic loading. The test results demonstrated that cyclic loading parameters such as average load P0 and load amplitude PA have a significant effect on the dynamic performance of the tiered walls. However, the change in loading frequency f has a minor effect on the settlement and lateral deformation when the GRS wall reaches a relatively stable state. Under the same P0 and PA, the measured maximum additional vertical stress Delta sigma v,max decreases with the increase of frequency f, whereas minimum additional vertical stress Delta sigma v,min increases. The stress distribution profile along the horizontal direction at the lower-tier wall crest is related to the strip footing location. The bearing capacity of the GRS wall increases and then decreases with increasing d/H within the reinforced zone of the upper-tier wall. The variation magnitude and distribution profile of the lateral deformations are influenced by the d/H and cyclic loading levels, especially for the upper-tier wall. When the strip footing remains in the reinforced zone of the upper-tier wall, potential slip surfaces go deeper as it moves away from the wall face. Finally, a power relationship between the calculated factor of safety and the maximum lateral deformation monitored from model tests for the two-tiered GRS walls under cyclic loading is established.

The aim of the present study is to assess the impact of rotational anisotropy on the undrained bearing capacity of a surface strip footing over an unlined circular tunnel on spatially variable clayey soil. The finite-difference method (FDM) is utilised to perform both deterministic and stochastic analyses. The Monte Carlo simulation approach is used to estimate the mean stochastic bearing capacity factor (mu Npro) and probability of failure (pf) of the entire system. The responses are evaluated for different geometric and spatially variable parameters and the strata rotation angle (beta). The failure patterns and the required factor of safety (FSr) corresponding to a specific probability of failure (e.g. pft = 0.01%) are determined for various parameters. The results obtained for the rotational anisotropy (beta$\ne \;$not equal 0) are observed to be significantly different from those for horizontal anisotropic structure (beta = 0), and considering only the horizontal anisotropic structure may lead to the overestimation or underestimation of the response of the structure.

Although considerable research has explored the static and seismic bearing capacity of strip footings on slopes or excavations, the influence of clay strength anisotropy on the bearing capacity of strip footing near excavations, specifically considering pseudo-dynamic conditions, remains unexplored. This study used the finite element limit analysis (FELA) method to evaluate the impact of clay strength anisotropy on the seismic bearing capacity of strip footings. The effects of various dimensionless parameters on the bearing capacity were examined, which include shear wavelength, the setback distance ratio, vertical height ratio, soil strength ratio, soil strength heterogeneity, anisotropic ratio, and horizontal and vertical acceleration coefficients. Design charts were developed to compute the seismic bearing capacity of strip footings on nonhomogeneous and anisotropic excavations under pseudo-static conditions. Furthermore, the effects of vertical acceleration coefficients and shear wavelength on the seismic bearing capacity of strip footing near excavation in nonhomogeneous and anisotropic soils were investigated.

Water table elevation leads to saturation of the soil surrounding the foundation. Saturated soil loses its load-bearing capacity due to suction reduction, becoming less stable and more prone to settling. This phenomenon can result in differential settlement, leading to uneven stress distribution on the structure. Over the last few years, substantial research efforts have been dedicated to analyzing the bearing capacity of saturated reinforced sand when subjected to loading at the foundation center, with limited attention given to unsaturated reinforced sand under eccentric loading. Eccentric loading can also result in additional stresses and moments that need to be considered in the design of the foundation to ensure its long-term integrity and functionality, especially when subjected to wetting conditions. Hence, this study investigated this aspect experimentally and numerically using the discrete element method (DEM) to uncover the intricate interactions between soil-reinforcement conditions, applied stress, and wetting-induced settlement. The results reveal that the geosynthetic reinforcement influences the extent of collapse settlement. While the reinforcement reduces collapse settlement, the enhancement is particularly notable when subjected to eccentric loadings. For both semisaturated and fully saturated conditions, the bearing capacity ratio (BCR) not only increases with the number of geosynthetic layers but also exhibits a higher rate for fully saturated sand than for the dry and semisaturated states. Unlike unreinforced sand where load eccentricity increases collapse settlement and differential settlement, reinforced sand experiences reduced settlement as load eccentricity increases. Finally, an empirical relationship by assessing the effect of the interface between the soil and the reinforcement layer was derived from regression analyses to predict the eccentric bearing capacity of strip footing under conditions of upward seepage. Alterations in pore-water pressure can influence the bearing capacity of shallow foundations. When the ground beneath a foundation reaches complete saturation, the in situ stresses that usually act as confining pressure experience an abrupt decrease. This phenomenon can induce additional settlements, which is very critical in foundation design applications, especially for foundations with eccentric loading, e.g., foundations subjected to wind load. Many shallow foundations are rested on deposits in coastal regions and along riverbanks. The failure due to the accumulation of pore-water pressure occurs when the shear stress applied by the superstructure surpasses the shear strength of the compromised soil. However, in cases where failure does not emerge, there remain issues related to serviceability and the potential for excessive settlement. This research demonstrates that the geosynthetic layers not only enhance the bearing capacity of strip footing but also show a greater improvement for eccentrically loadings in fully saturated sand compared to dry and semisaturated states.

By incorporating the bedding orientation of soil, this paper numerically investigates the effects of soil's anisotropic and heterogeneous behavior on strip footing under eccentric loading. The lower bound finite element limit analysis in association with second order cone programming is implemented to carry out the analysis by modeling cohesive soil as spatially random field. In order to generate the spatially random discretized soil domain, the well-known Cholesky decomposition technique is utilized. The probabilistic response is obtained by using the Monte Carlo simulation technique. The mean bearing capacity factor, failure probability of the footing for wide ranges of eccentricity, and soil heterogeneity are provided in design charts with respect to different bedding orientations. With the increase of eccentricity, the magnitude of the bearing capacity factor decreases in deterministic as well as probabilistic cases. At lower magnitudes of correlation lengths and eccentricity having different bedding orientations, significant variations are observed both in the magnitudes of mean bearing capacity factor and probability of failure; however, the variations are found to be minimized with the increase in the magnitudes of correlation lengths and eccentricity. Based on the obtained results, required factor of safety is evaluated for corresponding target probability by varying different bedding orientations.