平动模式下挡土墙非极限主动土压力

Non-limit active earth pressure for retaining wall under translational motion

针对平动模式下墙背倾斜的挡土墙,假定墙后所形成的土拱为圆弧形,建立位移同内摩擦角、外摩擦角的非线性函数,并考虑土层间剪应力作用,通过水平层分析法,得出了挡土墙平动模式下非极限主动土压力分布、合力、作用点高度的解答,其解析解与试验值较其他方法吻合得更好,验证了该方法的合理性。结果表明:是否考虑土层间剪应力,土压力的大小均随墙体位移的增大而减小,不会影响土压力合力大小,仅影响土压力的分布,且考虑剪应力作用的土压力在墙体上部较不考虑剪应力要小,下部反之。剪应力对土体起阻碍作用,随内摩擦角的增大,剪应力出现先显著增大后略微减小的状态;随外摩擦角、位移的增大,剪应力增大;随着墙背倾角的增大,剪应力先减小,再反向增大,土压力随之增大。同时考虑土拱效应与剪应力所得出的合力作用点高度介于仅考虑土拱效应与库仑解之间。

For inclined retaining walls under translational motion,the earth arch formed behind the wall is assumed arc-shaped.Nonlinear functions of displacement with internal and external friction angle,considering the interlayer shear stress,were established.The horizontal layer analysis method was used to obtain the solution of non-limit active earth pressure distribution,the total earth pressure,point of forces applied.The analytical solution and experimental values are in good agreement comparing to other methods.The results show that regardless of the inter-layer shear stress is considered or not,the magnitude of the earth pressure decreases as the wall displacement increases.The total of earth pressure does not change the magnitude but the distribution of earth pressure varies.The earth pressure considering the shear stress is less than the one in the upper part of the wall without considering the shear stress,and higher than the lower part.Shear stress acts as a hindrance to the soil,and it first increases significantly and then decreases slightly as the internal friction angle increases.Shear stress increases as the external friction angle and displacement increase.With the increase of the wall dorsal obliquity,the shear stress decreases first,then increases in the opposite direction,and the earth pressure increases accordingly.The height of the resultant force point considering the soil arching and shear stress together is between only considering the soil arching effect and the Coulomb solution.