动态规划法在搜索加筋土坡最危险滑动面的应用

本文采用非线性有限元法计算加筋土坡的应力场和位移场，依据剪应力法定义的安全系数，应用动态规划法搜索土坡的最危险滑动面。根据计算结果，对比了加筋前后土坡应力场和位移场的变化，分析了加筋对土坡侧向位移和最危险滑动面的影响。指出因加筋材料承担了部分剪应力，约束了土体的侧向位移，从而减小了土中的水平应力，扩散了剪应力，增大了土坡的安全系数。同时，计算分析了加筋材料摆放位置不同时，对土坡抗滑能力的影响效果。提出当将加筋材料贯穿于土中塑性区时，加筋效果最明显。对于较弱地基的土坡，筋材放置在坡底，有利于坡身荷载在地基土中的应力扩散，对限制地基土的侧向位移，提高土坡的安全系数有明显的效果。

Application of dynamic programming method in searching most dangerous slip surface of reinforced slopes

The nonlinear FEM is used to calculate the stress field and displacement field of geosynthetic reinforced slopes and the dynamic programming method is applied to search the most dangerous slip surface. The safety coefficient of the slip surface is defined as the ratio of the critical shear intensity during failure to real shear stress. The calculation result shows that the reinforcements bears part of the shear stress and constraints the flank displacement of the slope, thus reduces the horizontal stress and increases the safety coefficient. The result also reveals that the reinforcement material penetrating into the plastic zone of the slope will effectively elevate the slip resistance effect. For slopes on weak foundation, the reinforcement must be set at the bottom of the slopes.