地下水位上升引起斜坡变形的完全耦合分析

降雨是导致斜坡破坏的主要原因。地表水冲蚀与渗入、地下水运动都可能引发松散斜坡破坏。地下水位上升和地下水在土中渗流引起土体应力状态变化是导致斜坡在降雨过程中或降雨后变形与破坏的关键因素。本文采用完全耦合有效应力分析程序和与状态相关的剪胀性砂土模型模拟斜坡因地下水位变化而发生的变形。通过逐步改变初始和终止地下水位间土单元中孔隙水的密度模拟地下水位上升的效应。完全耦合方法可以模拟孔隙水和土骨架间漂浮和渗透的相互作用。本文分别模拟松散斜坡、回填压实斜坡和填石斜坡等3种斜坡的性能。分析结果表明:填土密度和斜坡排水条件是影响斜坡因地下水位上升而变形和破坏的重要因素。

Fully coupled deformation analysis of slopes due to rise of ground water level

Rainfall is the most important cause of slope failures. Surface erosion, surface infiltration and movement of ground water are possible triggering mechanisms of failures in loose filled slopes. The variation in stress state of soils due to the rise of ground water level and seepage of ground water is critical to the deformation and failure of slopes during and after heavy rainfall. The deformation of slope caused by change of ground water level was investigated by adopting a fully coupled procedure and the state-dependent dilatant sand model. The effect of the rise of ground water level was simulated by increasing the mass density of pore water in the soil elements between the initial and targeted ground water levels. The interaction between pore water and soil skeleton including both buoyancy and seepage effects could be precisely taken into account in a fully coupled effective stress approach. A loose filled slope, a compacted filled slope and a rock filled slope were analyzed. It was indicated that the density of the filled soil and the drainage condition of the slope were the major factors controlling the deformation and failure of slope caused by the rise of ground water level.