季节性冻土区桩基础桥梁地震反应研究  

Study of Seismic Responses of Bridge with Pile Foundations in Seasonal Frozen Soil Area

作　　者：王常峰[1] 陈兴冲[2] 丁明波[2] 

机构地区：[1]烟台大学土木工程学院,山东烟台264005 [2]兰州交通大学土木工程学院,甘肃兰州730070

出　　处：《桥梁建设》2016年第2期48-53,共6页Bridge Construction

基　　金：国家自然科学基金项目(51368036);长江学者和创新团队发展计划资助项目(IRT1139)~~

摘　　要：为研究土的不同状态对桩基础桥梁地震反应的影响,以青藏线某跨度32m的高桩承台简支梁桥为工程背景进行分析。根据桩基础桥梁的振动特点,建立非线性有限元动力模型,分别分析冻土和非冻土2种不同状态下结构的地震响应。结果表明,冻土状态下承台加速度反应及振动频率较大,非冻土状态下承台的水平位移、桩尖压入变形及震后残余缝隙较大;非冻土状态下桩的水平位移较大,冻土状态下桩的剪力及弯矩最大值较大;冻土模型桩顶部内力较大,内力较大值的分布区域相对较小;非冻土模型桩底部内力较大;承台底部力~位移滞回曲线在冻土状态下呈滑移接触的特点,非冻土状态下呈饱满的纺锤状。To study the influences of the different state of soil on the seismic responses of the bridge with pile foundations in the seasonal frozen soil area,a 32-m span simply-supported girder bridge with elevated pile caps on Qinghai-Tibet Railway was cited as an example and was analyzed.In the light of the vibration characteristics of the bridge with pile foundations,the nonlinear finite element dynamic model was set up and the seismic responses of the bridge under the two types of the state of the frozen soil and non-frozen soil were respectively analyzed.The results of the analysis indicate that under the frozen soil,the acceleration responses and vibration frequencies of the pile caps of the bridge are great and under the non-frozen soil,the horizontal displacement of the pile caps,the pressed deformation of the pile tips and the residual gaps after earthquake are great.The horizontal displacement of the piles under the non-frozen soil is great and the maximum values of the shear forces and bending moment of the piles under the frozen soil are great.The internal forces in the tops of the frozen soil model piles are great and the distribution areas of the great values of the internal forces are relatively small.The internal forces in the bottoms of the non-frozen soil model piles are also great.The force^displacement hysteretic curves of the bottoms of the pile caps under the frozen soil exhibit the characteristic of the sliding contact while under the non-frozen soil,exhibit the full spindle shape.

关 键 词：桩基础 冻土 地震反应 有限元法 桩-土-结构动力相互作用 抗震设计 

分 类 号：U443.15[建筑科学—桥梁与隧道工程] U442.55[交通运输工程—道路与铁道工程]