一种考虑主应力偏转的平移挡墙地震土压力算法

A Method for Seismic Earth Pressure of Retaining Walls under Translation Mode Considering Principal Stress Rotations

遵循Mononobe-Okabe理论,考虑墙后破裂体内的主应力偏转,并假设小主应力偏转迹线形状为圆形下段部分的一段,通过转动挡土墙的解析模型,再结合库伦土压力的相关概念得到地震主动破裂角。采用微分薄层法,对墙后滑裂微元体进行应力解析,推导得到平移模式(T模式)下的地震主动土压力的计算公式,并分析了土中各参数以及地震动系数对地震土压力的影响情况。本文旨在改进地震土压力算法,不仅在计算中考虑了主应力的偏转,而且大大简化了地震土压力的计算过程。最后将计算值与前人方法及试验数据进行对比,结果显示本文算法得到的地震主动土压力分布与模型试验数据更为吻合。

Based on Mononobe-Okabe theory,considering the principal stresses rotation and assuming that the trajectory of minor principal stresses is a lower part of a circle,on the basis of Coulomb earth pressure theory,the seismic active rupture angle obtained by rotating calculation model in this paper. And new formulae for seismic active pressure on rigid retaining walls under translation mode(T mode) then derived by the method of horizontal layer analysis,moreover,the influences of soil parameters and seismic coefficients on the seismic active earth pressure analyzed. This paper aim to improve the calculation method of seismic earth pressure,not only the principal stresses rotation considered in the calculation,but also greatly simplifie the process of calculation. Finally,compared with the existing theory,the distribution of the normalized lateral seismic active earth pressure of proposed method are in consistence with the results of model test.