考虑温度效应的圆形均布载荷下沥青混凝土场坪的动力响应分析

摘要

By transforming viscoelastic materials'integral type constitutive equation with Laplace Transformation, the viscoelastic operator described with Maxwell model was deduced.Then time-temperature equivalent principle was introduced to reflect the influence of temperature on mechanical property of asphalt concrete.By means of Laplace transformation and Fourier transformation for dynamic equilibrium equations,geometric equations and physical equations of visco-elastic problems in a rectangular coordinate system,the transfer matrix of axisymmetrical problems in a multi-layered viscoelastic half space was derived.Based on the transferring relation and known boundary conditions,the solution to surface vertical displacements of an asphalt launching site was derived and the computing program was complied by using MATLAB software.Taking a three-layer launching site as an example,its dynamic response under circular distributed load was analyzed.Results indicated that the settlement and residual deflection increase gradually with increase in temperature;the higher the temperature,the more obvious the local deflection phenomenon.%对黏弹性材料的积分型本构关系进行 Laplace 积分变换，推导出采用广义 Maxwell 模型描述的黏弹性算子，并引入“时温等效”原理来反映温度对沥青混凝土力学性能的影响。将直角坐标系下黏弹性问题的动力平衡方程、几何方程以及物理方程进行 Laplace 变换和二维 Fourier 变换，建立了多层黏弹性体系的传递关系。在此基础上，根据已知边界条件给出了场坪表面垂向位移的求解方法，并利用 Matlab 软件编写计算程序。以三层沥青混凝土场坪为例，分析了考虑温度效应的圆形均布动载荷下场坪的动力响应。结果表明，温度越高，场坪下沉量越大，局部弯沉现象越明显，残余变形也愈大。