回填砂土重力式挡土墙地震动土压力研究

Study of Seismic Active Earth Pressure Acted on Gravity Wall in Backfill Sand

引用液化度概念定义超静孔隙水压力比发展水平,考虑液化度的时程特征,将土压力视为随着液化度的增加由固体土的动土压力逐渐过渡到粘性流体的动水压力,采用拟动力法推导了动土压力大小、作用点位置以及动土压力分布形式的理论计算方法。结果表明:与Mononobe-Okabe拟静力法和Coulomb静力理论计算结果相比,拟动力法可计算出安全经济的动土压力系数与破坏楔角;动土压力为不规则的非线性分布,液化度较小时呈上抛物线形,液化度较大时呈下抛物线形,且高液化度下,内摩擦角、墙背摩擦角以及地震波放大效应对动土压力的影响减弱。

The concept of extent of liquefaction was applied to definition of the development level of excess pore water pressure ratio.Considering time history character of the extent of liquefaction,the seismic active earth pressure was regarded to convert solid earth pressure to viscous dynamic water pressure with increase of extent of liquefaction.Using pseudo-dynamic method,theoretical calculated methods of seismic active earth pressure,distribution of earth pressure and acting point positions of dynamic earth force were deduced.Results show that compared the method with pseudo-static Mononobe-Okabe method and static Coulomb method,the present method can be used to calculate safe and economic results of earth pressure coefficient and damaged wedge angle.Seismic active earth pressure with non-linear distribution increases with increase of depth of wall.It is upper parabola distribution under low extent of liquefaction and is down parabola distribution under high extent of liquefaction;influence of inner friction angle,angle of wall friction and magnification effect of seismic wave on seismic active earth pressure is weakened under high extent of liquefaction.