加筋路基动力特性的数值模拟研究  

Numerical Simulation of Dynamic Behavior of Reinforced Subgrade

作　　者：耿敏 王德斌[2] 李培勇[2] 高超 GENG Min;WANG Debin;LI Peiyong;GAO Chao(Institute of Geotechnical Engineering, Dalian University of Technology, Dalian,Liaoning 116024, China;College of Civil and Safety Engineering, Dalian Jiaotong University, Dalian, Liaoning 11602S, China)

机构地区：[1]大连理工大学岩土工程研究所,辽宁大连116024 [2]大连交通大学土木与安全工程学院,辽宁大连116028

出　　处：《水利与建筑工程学报》2018年第1期211-215,共5页Journal of Water Resources and Architectural Engineering

基　　金：国家自然科学基金项目(51408093);辽宁省教育厅科学研究项目(JDL201617);辽宁省博士科研启动基金项目(201601255)

摘　　要：基于前期的室内动三轴试验结果,采用FLAC^(3D)有限差分软件,通过建立轨道与路基的三维实体模型,探讨列车荷载作用下路基在不同的动应力幅值、格栅埋置深度、加筋层数时的应力、变形规律,为轨道路基的优化设计和力学参数的选取提供参考依据。研究结果显示:随着动应力幅值的增大,路基表面应力呈马鞍形分布的状态愈加明显,最大压应力位于地基深处,且在三种动应力幅值下均没有明显变化,说明动应力沿路基深度的衰减规律受车速的影响较小。路基的竖向应力随格栅埋置深度的增加出现了先减小再增大的趋势,这说明在路基内铺设格栅的位置宜选择在路基顶部或中下部,土工格栅的铺设加速了路基动应力的衰减,具有一定的减振作用,从而改善了路基结构动力响应特征,增强了路基的抗振性能。In order to effectively prevent and reduce the damage of reinforced subgrade caused by cyclic loading,it is necessary to study dynamic behavior of reinforced subgrade to ensure the safety and efficient operation of railway.In this paper,the track-subgrade models were constructed by using FLAC3D finite difference software.Based on the cyclic triaxial test results,numerical parametric studies were carried out to investigate the dynamic behavior of reinforced subgrade un-der cyclic loading.The studied parameters include dynamic stress amplitudes,embedded depths of geogrid,and different layer numbers.The results provide reference for the optimum design of track subgrade and the selection of mechanical pa-rameters.The numerical results indicated that with the increase of dynamic stress amplitudes,the saddle-shaped distribu-tion of dynamic stress of subgrade surface is getting more and more obvious.The maximum compressed stress is located in the depth of foundation.There is no obvious change of dynamic stress of subgrade in three dynamic stress amplitudes.It showed that the attenuation law of dynamic stress along the depth of subgrade rarely affected by the speed.With the in-crease of embedding depth of geogrid,vertical stress of subgrade first decreases and then increases.This illustrated that the proper locations of laying geogrid are at the top of subgrade or middle-lower part of subgrade.The Laying of the ge-ogrid can accelerate attenuation of dynamic stress of subgrade.It has a certain damping effect and can improve dynamic behavior of subgrade structure,then enhance anti-vibration capability of subgrade.

关 键 词：循环荷载 加筋路基 动力特性 数值模拟 FLAC3D 

分 类 号：U211.3[交通运输工程—道路与铁道工程]