海啸作用下滨水挡土墙抗震滑动稳定性上限分析

Upper-bound limit analysis of seismic sliding stability of waterfront retaining walls under tsunami loading

针对沿海地区滨水挡土墙在海啸和地震联合作用下易发生被动破坏的问题,结合极限分析上限法和拟静力法确定地震荷载,研究了海啸作用下滨水挡土墙的抗震滑动稳定性。通过建立墙体滑动与破坏区土楔体整体滑动的墙-土系统及速度容许场,推导出水平地震加速度系数(kh)的表达式。分析了海啸、海平面与地下水高度及墙-地和墙-土摩擦角对地震屈服加速度系数的影响。结果表明,控制地下水位在适当高度并增大墙-土摩擦角可以有效提高滨水挡土墙的抗震滑动稳定性。与经典极限平衡理论相比,该方法考虑了土体的塑性流动及挡土墙的位移模式,且无需计算地震被动土压力的值。

Aiming at the problem that waterfront retaining walls in coastal areas are prone to passive failure under the combined effect of tsunami and seismicity,the seismic load was determined via the upper-bound limit analysis theory and the pseudo-static method to investigate the seismic sliding stability of coastal retaining walls under the action of tsunamis.The wall-soil system and velocity permissible field of the sliding of the wall and the whole failure wedge were established to derive the expression of the seis⁃mic acceleration coefficient(kh).The effects of tsunami height,sea level height,groundwater level,wall-soil friction angle,and wall-soil friction angle on the seismic yield acceleration coefficient kcr were analyzed.The results show that the seismic sliding stabil⁃ity of coastal retaining walls can be effectively improved by controlling the groundwater level at an appropriate height and increasing the wall-soil friction angle.Compared with classical limit equilibrium theory,this method considers the plastic flow of soil and the displacement mode of retaining walls,and does not require the calculation of seismic passive earth pressure values.