降雨入渗作用下膨胀土挡土墙侧向土压力研究

Research on Lateral Earth Pressure from Expansive Soil Acting on Retaining Wall Under Rain Infiltration

膨胀土挡土墙在降雨时受侧向膨胀土压力的作用,容易发生失稳破坏。为深入认识降雨作用下膨胀土挡土墙发生变形破坏的机理,通过室内模拟降雨模型试验,对膨胀土挡土墙侧向土压力的变化规律进行了研究。研究表明:挡土墙后侧向膨胀土压力反应滞后于降雨,且在降雨初期呈顶部大、中间小的曲线分布形式,这容易导致挡土墙顶部产生剪切破坏;表层侧向土压力较深层的小,且较快达到稳定;深层侧向土压力在降雨之后随着雨水的下渗会产生递增,当其达到最大值后突然递减,这与深层土体浸水饱和产生软化有关。

Retaining wall working with expansive soil is prone to failure under rainfall infiltration, which is mainly caused by the lateral earth pressure from expansion soil. For further understanding this deformation failure mechanism, the paper studied the variation and distribution rules of lateral earth pressure on expansive soil retaining wall with a series of laboratory model tests under rainfall infiltration. The results show that the lateral earth pressure of expansive soil acting on the back of retaining wall respond lagging to rain, and the distribution curve shows the lateral earth pressure of expansive soil at top is bigger than that in the middle at beginning of rain, which is easy to cause shear failure at the top of retaining wall;the earth pressure at top is smaller and reaches stability sooner than that in deep part;the earth pressure in deep part progressive increases as the rainfall infiltration, and suddenly diminishes until reaching the maximum because deep soil is saturation softened.