水平柔性拉筋式重力墙地震土压力拟静力分析方法

Seismic earth pressure quasi-static analysis method for horizontal flexible reinforced gravity wall

水平柔性拉筋式重力墙是一种新型耐震结构,为研究墙后地震土压力,运用拟静力法并基于塑性极限分析上限原理,采用平面滑动破坏机构,考虑拉筋拔出和拉断两种破坏模式,推导墙后地震土压力的计算公式,并通过数值模拟方法进行验证,且讨论了填土内摩擦角、黏聚力、墙背外摩擦角、拉筋间距、极限拉力以及拉筋长度对地震土压力的影响特征。实例分析结果表明:随填土强度参数的增大地震土压力总体呈非线性减小,墙背外摩擦角对地震土压力的影响较小;随拉筋竖向间距增大,土压力呈非线性增大,但增幅渐小;拉筋极限拉力达到一定值后,对土压力没有影响;随拉筋长度在一定范围内的增加,墙后土压力逐渐减小。

The gravity wall anchored horizontally with flexible reinforcements is a new type of anti-seismic structure.In order to determine the seismic earth pressure on the wall,based on the pseudo-static method and the upper bound limit analysis principle with planar sliding failure mechanism,calculation formulas of seismic earth pressure on the wall is deduced considering two possible failure modes including pulling out and pulling off of the reinforcements.The proposed method is verified by a numerical simulation method for a practical example.The influences of internal friction angle and cohesion of earth fill,friction angle of the wall back,vertical spacing between reinforcements,and ultimate tensile force and length of the reinforcements on the seismic earth pressure are specifically discussed.The results show that the seismic earth pressure decreases nonlinearly with the increase in shear strength parameters of the fill,and the external friction angle of the wall has little effect on the seismic earth pressure.Also,as the vertical spacing between the reinforcements increases,the earth pressure increases nonlinearly but the gradient is progressively smaller;after the ultimate tensile force of the lacing reaches a certain value,it has no effect on the earth pressure;as the length of the lacing increases within a certain range,the earth pressure gradually decreases.