冻土层对桩基础铁路重力式桥墩抗震性能的影响研究  

Study on the influence of frozen soil layer on seismic performance of railway gravity bridge piers with pile foundation

作　　者：徐振江 张熙胤[1] 管嘉达 于生生 孙斌洁 张益舶 XU Zhenjiang;ZHANG Xiyin;GUAN Jiada;YU Shengsheng;SUN Binjie;ZHANG Yibo(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China)

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070

出　　处：《地震工程与工程振动》2024年第1期225-236,共12页Earthquake Engineering and Engineering Dynamics

基　　金：国家自然科学基金项目(52068045);甘肃省科技计划项目-杰出青年基金项目(20JR5RA430);中国国家铁路集团有限公司科技研究开发计划(P2021G047)。

摘　　要：为研究冻土影响下桩基础铁路重力式桥墩的地震破坏特征以及不同影响因素对季节性冻土区桩基础铁路重力式桥墩抗震性能的影响,首先通过拟静力模型试验研究了冻土影响下桩基础铁路重力式桥墩的地震破坏特征;其次建立了考虑冻土效应的桩基础桥墩有限元分析模型,采用数值模拟方法探讨了季节性冻土层厚度、剪跨比、轴压比和承台埋入深度4个参数对冻土区桩基础铁路桥墩抗震性能的影响。研究结果表明:在一定范围内季节性冻土层厚度的增加有利于提高桩基础铁路重力式桥墩的抗震性能,但当冻土层厚度超出这一范围再增加时,其对桩基础桥墩水平承载能力的影响会变弱,同时冻土层厚度的增加会加速桩-土-桥墩体系的破坏;剪跨比的增大和承台埋入深度的减少均会显著降低冻土影响下桩基础桥墩的抗震性能;轴压比的增大会提高桩基础桥墩的水平承载能力,但会加速桩基础桥墩峰值荷载的出现,同时也会加速桩-土-桥墩体系的破坏。This paper aimed to investigate the seismic failure characteristics of the railway gravity piers with pile foundation under the influence of frozen soil layer and the influence of different influencing factors on the seismic performance of railway gravity piers with pile foundation in the seasonal frozen soil region.Firstly,the seismic damage characteristics of the railway gravity bridge pier with pile foundations in frozen soils were investigated by quasi-static model test.Secondly,a finite element model of bridge pier with pile foundation considering frozen soil effect was established.Then,the influence of the seasonal frozen soil layer thickness,shear-span ratio,axial compression ratio and bearing depth of pile cap on seismic performance of the railway gravity bridge pier with pile foundation was discussed by numerical simulation method.The results showed that the increase of seasonal frozen soil layer thickness in a certain range is beneficial to improve the seismic performance of the railway bridge pier with pile foundations,but if the frozen soil layer thickness increased beyond this range,its influence on the lateral bearing capacity of the bridge pier is weakened and the damage of pile-soil-pier system will be accelerated.Increasing the shear-span ratio and decreasing the embedded depth of the pile cap can significantly reduce the seismic performance of the bridge pier with pile foundations in frozen soils.Increasing the axial compression ratio can increase the lateral bearing capacity of the bridge pier with pile foundations,but it will accelerate the appearance of peak load of the bridge pier with pile foundations and accelerate the damage of the pile-soil-pier system.

关 键 词：季节性冻土 桩基础 铁路重力式桥墩 抗震性能 滞回耗能特性 

分 类 号：U24[交通运输工程—道路与铁道工程]