A series of shaking table tests were carried out to explore the dynamic characteristics and working mechanisms of wrapped-face reinforced soil-retaining walls under strong vibration. Under the 0.1–1.0 g horizontal peak ground acceleration (HPGA), the damping ratio of sand shows a downward trend as a whole, so the acceleration amplification coefficient decreases with the increase of HPGA. However, when HPGA reaches 1.0 g, the acceleration amplification coefficient increases; the range of acceleration amplification coefficient at the top of the wall is 1.69–1.36. When HPGA is 1.0 g, the maximum cumulative residual displacement of the panel is 2.96% H, and the maximum uneven settlement of the sand is 3.57% H, both of which have exceeded the limit of the specification. With the increase of HPGA, the ratio of the dynamic earth force increment to the total dynamic earth force gradually approaches 50%. Since the reinforcement effect of geogrid is not considered, the predicted value of traditional earth pressure theory is different from the measured value. According to the Washington State Department of Transportation displacement index, the deformation range of wrapped-face reinforced soil-retaining walls is divided into three stages: the quasi-elastic stage, the plastic stage, and the failure stage.
The interaction between reinforcement and soil is a key problem in the application of geosynthetics as reinforcement in geotechnical engineering. In this study, tensile and pull-out tests on a uniaxial geogrid were carried out using self-designed tensile and pull-out test equipment. The tensile test evaluated the tensile load–strain characteristics of a geogrid. Under the condition of lateral confinement, the tensile force and secant tensile stiffness of the geogrid increased with an increase in the normal stress when the strain was constant, and the secant tensile stiffness decreased with a decrease in the tensile rate. The stiffness coefficient was used to quantitatively describe the change in the stiffness of the reinforcement. Using the pull-out test, the variation laws of the pull-out force of the geogrid under different normal stresses and different longitudinal rib percentages were obtained. When the geogrid was broken, the pull-out force of the same type of geogrid was not significantly different under different normal stresses. With an increase in the longitudinal rib percentage, the pull-out force of the geogrid under the same normal stress gradually increased, and the apparent friction coefficient was obtained by analysis. The results of the apparent friction coefficient obtained by the analytical method in accordance with French specifications (NF P94-270-2020) are relatively safe compared to the experimental values.
To understand the macroscopic fracture behavior of shale under different confining pressures, it is necessary to study the process of microcrack propagation from a microscopic perspective. In this study, a cohesive zone model for heterogeneous shale based on mineral distribution was constructed. Numerical simulation experiments were conducted under different confining pressures to investigate the effects of confining pressure on the extension of microcracks under tensile and shear loading from three perspectives: microcrack morphology, acoustic emission characteristics, and mechanical responses of different minerals. This study reveals the influence of different confining pressures on the extension of microcracks under tensile and shear loading conditions in shale and their microscopic mechanisms, which holds theoretical and practical significance for the exploitation of deeply buried shale gas.
The response mechanisms of reinforced soil retaining wall structures under rainfall infiltration are not fully understood, leading to insufficient design guidelines. This study investigates a modular reinforced soil retaining wall model employing concrete blocks as the facing panel, standard sand as backfill, and a biaxial geogrid as reinforcement. Three sets of tests with varying rainfall intensities (150 mm/h, 300 mm/h, and 450 mm/h) were conducted to analyse and compare the response patterns of rainwater infiltration, earth pressure distribution, reinforcement strain, and displacement characteristics. The results indicate that with increasing rainfall intensity, the depth of infiltration influence extends across the entire wall section, with significant water accumulation at the base under heavy rainstorm conditions. The distribution pattern of static earth pressure is generally consistent across tests; however, a notable abrupt change reaching 8.59 kPa was observed at mid-height under rainstorm conditions. The strain increment distribution in the reinforcement is non-uniform, with increments under heavy rain and heavy rainstorm conditions being less than those under rainstorm conditions. The displacement of the wall panel is greatest in the middle and upper sections, with the smallest displacement occurring under rainstorm conditions. The displacement pattern shows a negative correlation with both the static earth pressure and the reinforcement strain patterns. These findings provide theoretical support for drainage design and stability control of reinforced soil retaining walls in regions experiencing heavy rainfall.