移动荷载作用下非饱和土地基动力响应分析

Analysis of dynamic response of unsaturated soil foundation under moving loads

基于非饱和多孔介质理论的研究成果,考虑土颗粒、孔隙流体的压缩性及各相物质间的黏性、惯性耦合作用,建立了移动荷载作用下非饱和土地基的动力控制方程。结合坐标变换,采用Fourier变换和Helmholtz矢量分解原理,获得了地表透水透气边界条件下频域内非饱和土位移、孔隙水压和孔隙气压的表达式。通过数值算例,分析了荷载移动速度、饱和度以及边界条件等因素对非饱和土地基动力响应的影响规律。结果表明:该边界条件下地表竖向位移随饱和度与荷载移动速度的提高而增大;孔隙水压和孔隙气压在透水透气时沿深度方向先增大后减小。

Based on the theory of unsaturated porous media,the dynamic control equations of unsaturated soil foundation under the action of moving loads are established by considering the compressibility of soil particles,pore fluid and the viscous and inertial coupling effects of each phase material.Fourier transform and Helmholtz vector are used to decompose the principle combining with coordinate transformation.Thus,the expressions of unsaturated soil displacement,pore water pressure and pore air pressure in the frequency domain are obtained under the surface permeability boundary condition.The influence law of load movement speed,saturation degree and boundary conditions on the dynamic response of unsaturated ground foundation is analyzed through numerical calculations.The results show that the vertical displacement of the surface under the boundary conditions increases with the increase of saturation degree and load movement speed,while the pore water pressure and pore air pressure increase and then decrease along the depth direction at the time of permeable gas.