宁波站深基坑施工中便桥立柱的隆沉研究  

Research on Uplift Subsidence for Auxiliary Bridge Pillar in Deep Foundation Pit Construction of Ningbo Railway Station

作　　者：王雨涝 Wang Yulao(China Civil Group Southern Construction Co.Ltd.,Zhuhai Ouangdong 519000,China)

机构地区：[1]中土集团南方建设有限公司,广东珠海519000

出　　处：《铁道建筑技术》2018年第9期45-49,共5页Railway Construction Technology

基　　金：山西省太原高新区创新基金项目(11CXJJ-35);中国铁建股份有限公司科技研发计划项目(11-25C)

摘　　要：在宁波火车站深基坑开挖过程中,穿越深基坑的运营铁路便桥出现了钢格构立柱(断面尺寸600 mm×600mm)隆起的现象。本文通过对引起立柱隆起原因的分析,利用土力学布辛纳斯克解(Boussinesq1885)建立桩基摩阻力和桩底反力的关系,计算出开挖前后摩阻力的变化值,同时计算出桩基在桩底以下各土层中产生的附加应力;利用分层总合法计算出桩底位移变形,再计算出桩顶的竖向位移,加入钢格构立柱的热胀冷缩变形,得到立柱最终隆沉值。施工过程中,采取对钢格构柱浇水降温和加快底板浇筑的措施,确保基坑开挖和既有线铁路运行的安全。In the process of deep foundation pit excavation of Ningbo Railway Station, the uplift of steel grid columns was happened in the operation railway auxiliary bridges while crossing deep foundation pit. In this paper, through analyzing the cause of column uplift, establishing the relationship model between pile friction resistance and pile bottom reaction force by Boussinesq1885, the change of frictional resistance before and after excavation was calculated, and the subsidiary stress of foundation pile in different soil layers at the bottom of pile was obtained. The displacement deformation of the pile bottom was calculated by using the stratified summation method, and the vertical displacement of pile-top was calculated, adding the thermal expansion and contraction deformation of the steel lattice column, then the final uplift value of the column was reached. Some measures were taken in the construction, such as cooling the steel lattice column by watering and accelerating casting the bottom slab, which could ensure the safety of excavating the foundation pit and the running of the existing railway.

关 键 词：基坑 立柱 桩基 附加应力 竖向位移 

分 类 号：TU753.3[建筑科学—建筑技术科学]