RB模式下挡墙的地震非极限主动土压力分析

Analysis of seismic on-limit active earth pressure of retaining wall in RB mode

基于拟动力法和水平层分析法,以地震荷载下的刚性挡土墙为研究对象,依据已有试验研究结论,考虑挡墙位移对摩擦角发挥值的影响,推导得出RB模式下地震非极限主动土压力和合力作用点的计算表达式。计算模型根据墙顶最大位移的不同分成2种非极限状态工况,并建立挡墙位移,地震动荷载和土压力之间的相互联系。讨论墙顶位移对地震侧土压力的分布、摩擦角发挥程度、土压力合力作用点的影响。结果表明,水平或竖向地震作用以及挡墙非极限的位移状态都能使主动土压力的合力作用点升高。相比于传统的极限状态地震土压力理论,所提方法更合理地描述了地震土压力随挡墙位移的发展过程,对发展非极限土压力理论和改进实际工程中的抗震计算方法具有一定的参考意义。

Based on the pseudo-dynamic method and the horizontal layer analysis method,the rigid retaining wall under seismic load is taken as the research object.According to the conclusions of previous experimental research,the calculation expression of seismicnon-limitactive earth pressure and resultant force point in RB mode is derived,which considers the influence of the retaining wall displacement on the exerting value of friction angles.The calculation model is divided into two kinds of non-limit state conditions according to the difference of the maximum displacement of the wall top,and the relationship between the displacement of the retaining wall,the seismic load,and the earth pressure is established.The parametric analysis discusses the influence of the displacement of a wall top on the distribution of the seismic lateral earth pressure,the exertion degree of the friction angle and the resultant force point of the earth pressure.The results indicate that the horizontal or vertical seismic action and the non-limit displacement state of a retaining wall can both increase the resultant force point of active earth pressure.Compared with the traditional limit state seismic earth pressure theory,the proposed method describes the development process of seismic earth pressure with retaining wall displacement more reasonably and has a certain reference for developing non-limit earth pressure theory and improving seismic calculation method in practical engineering.