This study investigates the vulnerability of expansive soil slopes to destabilization and damage, particularly under intense rainfall, due to their heightened sensitivity to moisture. Focusing on a project in Yunnan Province, numerical simulation software is employed to address slope stability challenges. Meanwhile, the soil mechanical parameters of this study were acquired through experimentation. The analysis considers six conditions: unsupported, conventional anchor and stabilizing pile reinforcement, and NPR (Negative Poisson's ratio) anchor and stabilizing pile reinforcement, evaluated under both normal and rainstorm conditions. The research outcomes reveal noteworthy insights: (1) The efficacy of NPR anchors in mitigating deformation in expansive soil landslides is investigated, broadening their application potential, particularly in restricting maximum slope displacement compared to conventional anchors. (2) No significant difference in safety factors for slope stability is observed between NPR and conventional anchors. Under rainstorm conditions, safety factors are 1.39 and 1.32 for NPR and conventional anchor and stabilizing pile support, respectively, while under normal conditions, they are 1.42 and 1.39. (3) The NPR anchor, in contrast to the conventional anchor, ensures a more uniform force distribution across the stabilizing pile. (4) While combined support structures contribute to slope stabilization, NPR anchors surpass conventional anchors in limiting slope displacement.

Expansive soils exhibit directionally dependent swelling that traditional isotropic models fail to capture. This study investigates the anisotropic swelling characteristics of expansive soil with a medium swelling potential through the use of modified oedometric testing. Vertical swelling strains can reach up to 1.71 times that of the horizontal movements, confirming intrinsic anisotropy. A nonlinear elastic constitutive model incorporates vertical and horizontal elastic moduli with respect to matric suction to characterize anisotropy. Three elastic parameters were determined through the experiments, and predictive equations were developed to estimate the unsaturated moduli. The constitutive model and predictive techniques provide practical tools to better assess expansive soil pressures considering anisotropy, offering guidelines for utilization and design. The outcomes advance understanding of these soils' directionally dependent behavior and stress-strain-suction response.

In coastal regions of China, extensive areas are characterized by deep and thick silty clay deposits, necessitating excavation and support during engineering construction. This study gathers excavation examples from existing literature and aims to summarize and analyze the deformation characteristics of support structures and the soil behind these structures (supporting walls) resulting from excavation. The findings demonstrate a general trend of increasing maximum lateral displacement of the supporting wall with greater excavation depth. The ratio of maximum lateral displacement to excavation depth falls within the range of 0.18% to 0.64%, while the insertion ratio spans from 0.78 to 1.23. The ratio of maximum ground settlement behind the wall to excavation depth varies between 0.28% and 0.82%. Additionally, the ratio of maximum ground settlement behind the wall to the maximum lateral displacement of the wall ranges from 0.93 to 1.81. The statistical analysis results presented here offer valuable references for the design and construction of excavations in regions characterized by deep and thick silty clay deposits. Moreover, the statistical results can serve as qualitative verification for finite element analysis in specific cases.