运动荷载附近有限层厚软土地基的振动研究

基于Biot多孔弹性介质的波动理论,研究了运动荷载附近软土地基的振动问题.假设一条形均布荷载作用在地基表面,则该模型可视为平面应变问题进行分析.通过引入4个势函数和Helmholtz原理,并利用Fourier变换及逆变换技术,获得了运动荷载作用下软土地基的应力、位移和孔隙水压力的解答.利用离散Fourier逆变换得到数值计算结果,分析了荷载速度,频率以及软土的渗透系数及多孔弹性参数对运动荷载作用下地表竖向位移及土体中任一点孔隙水压力分布的影响.

Ground vibration of a finite layer of soft foundation in the vicinity of a moving load

Based on Biot’s wave equation, the transmission of vibrations over the surface of the ground due to a harmonic strip moving load, is investigated theoretically under conditions of plane strain. The material of subgrade is idealized as a uniform, fully saturated poroelastic finite-layer of soil obeying Biot’s dynamic poroelastic theory. By introducing four scalar potential functions and Helmholtz decomposition theorem, the analytical solutions of stress, displacement and pore pressure are derived using the Fourier transform and the inverse Fourier transform. Numerical results are obtained by using the inverse fast Fourier transform (IFFT), and are used to analyze the influence of the moving load velocity, frequency and, the permeability and porous elastic constant of the ground on the vertical displacement on the surface of the ground and the distribution of pore pressure along the arbitrary depth of ground.