刚性挡墙绕底部转动模式下有限土体非极限状态地震土压力

Non-limit State Seismic Earth Pressure for Limited Soil Under Rigid Retaining Wall Rotation Around the Bottom

摘要:

为探明刚性挡墙绕底部转动（RB）模式下有限土体非极限状态地震土压力变化规律，基于水平微分单元法和拟动力法，推导得出RB模式下挡墙间有限土体非极限状态地震土压力计算式，同时建立了对应的数值算法。实例分析显示，有限土体地震主动土压力表现出随时间变化的周期性特征与随深度变化的非线性特征，计算结果与振动台试验结果有良好的一致性。参数分析表明，地震侧土压力随初始内摩擦角的增加、墙底位移比的增加以及地震加速度系数的降低明显减小，地震土压力合力大小主要受初始内摩擦角和墙底位移比的影响，地震加速度系数则主要改变合力幅值，仅采用拟静力法进行的强震条件下挡墙抗震设计偏于不安全。研究结果可为实际工程中挡土结构抗震设计提供理论指导。

Abstract:

To investigate the variation of seismic earth pressure in limited soil under the rigid retaining wall base rotation （RB） mode at non-limit state， a seismic earth pressure calculation formula was derived based on the horizontal differential unit method and the pseudo-dynamic method. The corresponding numerical algorithm was also established. Example analysis shows that the seismic active earth pressure in limited soil exhibits periodic characteristics with time and nonlinear variations with depth， and the calculation results are in good agreement with the results of shaking table tests. Parameter analysis indicates that the seismic earth pressure decreases significantly with the increase of initial internal friction angle， wall base displacement ratio， and the decrease of seismic acceleration coefficient. The total seismic earth pressure is primarily influenced by the initial internal friction angle and wall base displacement ratio， while the seismic acceleration coefficient mainly affects the magnitude of the resultant force. It is shown that the seismic design adopting only the pseudo-static method tends to be unsafe under strong earthquake conditions. This method offers valuable theoretical insights for the seismic design of retaining structures in practical engineering applications.