移动荷载作用下层状正交各向异性地基平面应变问题动力响应
Dynamic response to plane strain problem of multilayered orthotropic foundation under moving loads
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摘要: 基于移动谐振荷载作用下单层正交各向异性地基的平面应变问题的动力方程,通过Fourier变换,引入状态向量,推导了直角坐标系下单层正交各向异性地基的传递矩阵,建立层状正交各向异性地基平面应变问题计算模型,利用传递矩阵方法,结合层间接触条件和连续条件,求得了直角坐标系下正交各向异性层状地基任意深度处的平面应变问题的位移和应力解析表达式。基于推导的理论方法,编制了相应的计算程序,验证了单层正交各向异性土体的计算结果,算例分析土体的分层特性和正交各向异性性质对土体变形的影响规律。研究结果表明:忽略土体的分层特性和上层土体的正交各向异性,不能准确描述地基的动力特性。Abstract: Based on the dynamic equation for plane strain problem of single-layer orthotropic foundation under moving harmonic loads, the transfer matrix of single-layer orthotropic foundation in the Cartesian coordinates is deduced through the Fourier transform and the introduction of state vector. Then the computational model for the layered orthotropic foundation is established. Considering the contact condition and the continuous condition between layers, the analytic expressions for the displacements and stresses at arbitrary depth in the plane strain problem of multilayered orthotropic foundation are derived by means of the transfer matrix method. Based on the theoretical solutions, the corresponding calculation programs are compiled to verify the calculated results of the single-layer orthotropic foundation and to study the influences of layered characteristics and orthotropic properties of soils on the amplitudes of vertical displacement of soil surface. The results indicate that neglecting the layered characteristics of soils and orthogonal anisotropy of the upper soils cannot accurately describe the dynamic characteristics of foundation.