简谐移动荷载下单相弹性地基三维动力半解析移动单元分析  

Three-dimensional dynamic semi-analytical moving element method for single-phase elastic foundation under harmonic moving loads

作　　者：曹彩芹[1] 黄义[1] 孔旭光[1] 

机构地区：[1]西安建筑科技大学,西安710055

出　　处：《应用力学学报》2012年第5期523-529,626,共7页Chinese Journal of Applied Mechanics

基　　金：陕西省教育厅专项基金(11JK0526)

摘　　要：由于路面不平整,车辆会以一定的频率和振幅在路面上运动,研究简谐移动荷载作用下单相弹性地基的动态响应具有更加现实的意义。将移动单元法引入到单相弹性介质的半解析方法中,构造了随荷载以相同速度运动的移动层单元。基于移动坐标下单相弹性介质的动力控制方程和边界条件,应用加权残数法建立了简谐移动荷载下单相弹性介质的三维动态响应半解析方程;将固定坐标下的动力问题转化为移动坐标下的拟静力问题,数值分析了简谐移动荷载作用下单相弹性地基的动态响应及其参数的影响。计算结果表明:在简谐移动荷载作用下,当无阻尼或小阻尼时,位移幅值随着速度变化不是单调递增或递减。当速度在瑞利波波速附近时,会出现各位移幅值的极大值(或第一极大值);当阻尼较大时,位移随着速度增加变化缓慢。这说明阻尼和频率的共同作用会有效地抑制位移幅值响应。研究结果表明本文所提供半解析移动单元法是研究简谐移动荷载下介质动态响应的一种简单有效的方法。Vehicles travel on the road pavement at a certain frequency and amplitude because of the uneven road,so the research of single-phase elastic foundation dynamic response under harmonic moving loads is of great realistic significance.Moving element method is introduced into the semi-analytical method of single-phase elastic medium,and moving layered element at the same speed with the loads are established.Based on single-phase elastic medium dynamic control equations and boundary conditions in moving coordinates,the weighted residual method is applied to establish three-dimensional dynamic response semi-analytical equations of single-phase elastic foundation under moving loads.Dynamic problem in fixed coordinates is transformed into the quasi-static problem in moving coordinates.Effects of load velocity,frequency and foundation damping on elastic foundation dynamic response are analyzed.When the damping is zero or little and the load speed is close to Rayleigh wave speed,the displacement amplitude reaches the maximum(or first maximum).While when the damping is big,displacement amplitude changes slowly with the speed increment.The results obtained show that the damping and frequency can effectively inhibit the displacement amplitude.Meanwhile,numerical calculation carried out indicates that the semi-analytical moving element method is effective and simple for the calculation and analysis of the dynamic responses of elastic foundation under moving loads.

关 键 词：移动单元法 简谐移动荷载 动态响应 半解析法 单相弹性地基 

分 类 号：TU435[建筑科学—岩土工程]