移动荷载作用下饱和土体上筏板-上部结构的动力响应分析

Dynamic responses of raft-superstructure on saturated soil under moving load

根据饱和土比奥理论与最小势能原理及薄板理论,采用子结构法,把上部结构、基础和地基作为一个共同作用的整体,在接触界面上满足变形协调条件,建立移动荷载作用下饱和土体地基-筏板-上部结构共同作用的积分方程。对积分方程的数值求解和相应的Fourier逆变换,得到任意时刻上部结构、筏板的内力和位移以及地基反力。最后通过数值计算,分析了饱和土体参数、移动荷载的速度等对上部结构水平、垂直方向的振动的影响特点。数值结果表明:上部结构各层的水平位移、竖向位移都随荷载速度增大而增加;竖向位移随楼层增加变化不大,当荷载速度较低时,水平位移随上部结构高度的变化曲线平滑少弯折,说明振动较稳定。但当荷载速度较高时,水平位移随楼层变化曲折越明显,层间差异大。

Based on Biot＇s theory and the minimum potential energy principle as well as the thin plate theory,the superstructure,raft and soil are assumed to be whole system according to the substructure method.The system must satisfy the continuity conditions at the interface between the superstructure,raft and soil surface.Considering the compatibility condition that the vertical displacement of the interface between the raft and the saturated soil should be equal,the integral equation accounting for the vertical coupling of the superstructure-raft system with the saturated soil subjected to a moving load is constructed.Using the numerical inverse transform technique,the forces and displacements of the superstructure,plate and saturated soil at any time are obtained.Some numerical results are presented to demonstrate the capacity of the proposed model.Numerical results show that the horizontal displacements and vertical displacements of each floor of the superstructure increase with increasing velocities of moving load.The vertical displacements in each floor have small change.Also,for a lower moving velocity,the curve of the horizontal displacements changes smoothly with the superstructure height increasing.When higher moving velocity,the curve of the horizontal displacements changes obviously with superstructure height increasing.