考虑抗剪强度衰减特性的膨胀土边坡稳定性分析

针对传统膨胀土边坡稳定性分析中无法考虑膨胀土在降雨入渗过程中抗剪强度动态衰减的问题，本文开展了室内直剪试验，系统研究了干密度和含水量变化对膨胀土抗剪强度指标的影响；同时，以试验抗剪强度结果为参数，开展了基于强度折减法的膨胀土边坡稳定性分析，获得了抗剪强度动态衰减过程中边坡稳定性的变化规律。结果表明，含水量的增加和干密度降低会造成膨胀土黏聚力和内摩擦角的衰减，黏聚力衰减显著，内摩擦角衰减较少；膨胀土边坡稳定性主要受风化层土体含水量控制，随着膨胀土含水量的增加，膨胀土边坡逐渐由稳定状态演变为欠稳定状态；干密度对膨胀土边坡稳定性的影响则相对较小。

Stability analysis of expansive soil slopes considering shear strength decay characteristics

In order to address the problem that the dynamic decay of shear strength of expansive soil in the process of rainfall infiltration cannot be considered in the traditional slope stability analysis of expansive soil, indoor direct shear test was carried out to systematically study the influence of dry density and water content on the indicators of shear strength of expansive soil, viz., cohesion and internal friction angle. At the same time, the stability analysis of the expansive soil slope based on the strength reduction method was carried out with the shear strength testing results, and the change law of slope stability with the dynamic decay of shear strength was obtained. The results show that the increase of water content and the decrease of dry density will cause the decay of cohesion and internal friction angle of expansive soil, and the decay of cohesion is significant, while the decay of internal friction angle is less; the stability of expansive soil slope is mainly controlled by the water content of weathering layer, and with the increase of water content of expansive soil, the slope gradually evolves from stable state to unstable state, while the influence of dry density on the stability of expansive soil slope is relatively small.