地铁施工对既有桥梁桩基的影响研究  

Analysis of Bridge Pile Responses Caused by Subway Construction

作　　者：杨广武 赵江涛[2] 苏洁[2] 

机构地区：[1]北京市重大项目建设指挥部办公室,北京100029 [2]北京交通大学隧道与地下工程教育部工程研究中心,北京100044

出　　处：《都市快轨交通》2014年第3期70-74,共5页Urban Rapid Rail Transit

基　　金：北京市科技计划项目(Z111100074211012);中央高校基本科研业务费专项资金资助项目(2012JBM079)

摘　　要：基于桩基与土体之间相互作用的分析可知,土体变形传递到既有桩基必然会引起桩基内力和位移的改变。以北京地铁7号线双线隧道近距离穿越双井桥工程为例,采用FLAC3D三维数值模拟软件分析地铁双线隧道在开挖和支护过程中,邻近桩基内力与变形的变化规律,仿真结果分析表明:桩基竖向沉降沿桩身变化不大,水平变形在隧道轴线位置达到最大;桩基轴力有明显的负摩阻增大区段,横向和纵向弯矩呈现S形变化规律;在隧道穿越桩基的过程中,桩基负摩阻力急剧增长会造成桩基承载力降低,施工中应采取适当的加固措施。Based on the analysis of interaction between piles and soil, it is known that the deformation of soil will pass to piles, and inevitably cause change of internal force and displacement of piles. Taking the project of double-track tunnel closely crossing the Shuangjing Bridge of Beijing subway Line 7 as an example, a FLAC^3D model of the project was established to simulate the excavation and supporting process, which aimed at analyzing the disturbance to the piles. The numerical simulation results show that the settlement of piles does not change much, but axial force of piles increases much, meanwhile,the horizontal deformation reaches maximum at the axis of tunnel. There is an obvious negative friction resistance increase region for the axial force, and its transverse and longitudinal bending moment curve shows S - shape. In the process of tunnel crossing the piles, the increasing negative skin friction will reduce the bearing capacity of pile; proper measures should be taken in the construction.

关 键 词：轨道交通 桥梁 地铁施工 桩基内力 桩基变形 数值模拟 

分 类 号：U215.7[交通运输工程—道路与铁道工程]