加筋土挡墙地震稳定性的拟动力分析

Pseudo-dynamic analysis of seismic stability of reinforced soil walls

为研究不同筋材条件下加筋土挡墙地震稳定性,采用两种简化破裂面形式;由于拟静力法的局限和加筋土挡墙的成层特性,对水平和竖向地震力同时作用下的加筋土挡墙,运用拟动力法和水平条分法推导出其筋材拉力总和与临界破裂角的计算公式。算例分析结果表明,筋材拉力总和随着地震加速系数、回填土重度或者滑动体上部超载的增大而增大;随着土体内摩擦角或者填土黏聚力的增大而减小;当条件相同时,可延展性筋材所承受的筋材拉力总和大于不可延展性筋材所承受的。与拟静力法和规范中的方法比较,基于拟动力法的加筋土挡墙的设计也更加经济。

In order to study seismic stability of soil walls reinforced with different materials, the two simplified failure surfaces are considered. Then, due to the limitations of pseudo-static method and the layering features of reinforced soil walls, the formula of the total reinforcement tensile force and critical angle of rupture is obtained by the combination of pseudo-dynamic method and horizontal slice method, considering both horizontal and vertical seismic force. The example analysis results show that the total reinforcement tensile force increases with the increase of seismic acceleration coefficient and unit weight of backfill or surcharge load; while it decreases with the increase of soil internal friction angle or cohesion. Furthermore, the total pullout reinforcement tensile force for flexible reinforcement material is larger than the total breakage reinforcement tensile force for rigid reinforcement material under the same conditions. Compared with the pseudo-static method and the method in the specification, the design of reinforced soil walls is more economic by using pseudo-dynamic method.