浸水条件地震主动土压力的改进拟动力法

Improved Pseudo-dynamic Method for Seismic Active Earth Pressure Under Submerged Conditions

基于极限平衡分析和拟动力法的计算思路,以无粘性填土的刚性挡土墙为研究对象,考虑填土处于无渗流的完全浸水条件,推导给出了浸水挡墙地震主动土压力的改进拟动力法的计算表达式.通过程序求解和参数分析表明:浸水条件下,拟动力法中的剪切波参数对土压力系数的影响胜于压缩波参数,计算所得的土压力曲线为"类S型";主动土压力值随内摩擦角的增大而显著减小,随水平地震加速度的增大而明显增大,竖向地震加速度对土压力影响较小,可以忽略不计.与干土的地震主动土压力对比,浸水后土压力系数有一定增大,并且两者的差异随着地震作用的增大而扩大.

The expressions of improved pseudo-dynamic method for seismic active earth pressure under submerged conditions were derived based on the limit equilibrium analysis and pseudo-dynamic method. The derivation aims at a rigid gravtiy wall retaining a cohesionless backfill under fully submerged condition without seepage. The parametric study indicates that the influences of the shear wave parameters in pseudo-dynamic method under submerged conditions are greater than those of the primary wave,then the earth pressure curve is S type. The active earth pressure decreases with the increase of soil friction angle,and increases with the increase of horizontal seismic acceleration. The vertical seismic acceleration has little effect on the earth pressure,thus can be neglected. Compared with the active earth pressure of dry soil,the earth pressure coefficient is larger than that under submerged condition,and the difference between the two increases with the increase of seismic action.