地铁盾构隧道穿越桥梁下方群桩基础的托换与除桩技术研究  

Pile underpinning and removing technology of shield tunnels crossing through group pile foundations of road bridges

作　　者：徐前卫[1,2] 朱合华[2] 马险峰[2] 马忠政[3] 

机构地区：[1]同济大学道路与交通工程教育部重点实验室,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092 [3]上海申通地铁集团有限公司,上海200010

出　　处：《岩土工程学报》2012年第7期1217-1226,共10页Chinese Journal of Geotechnical Engineering

基　　金：中央高校基本科研业务费专项资金项目(1600219169);同济大学岩土及地下工程教育部重点实验室开放基金资助项目(KLE-TJGE-B1108)

摘　　要：针对上海地铁10号线曲阳路—溧阳路区间隧道穿越四平路沙泾港桥群桩基础这一工程案例,结合对既有桥梁结构形式、现场周边环境、施工条件以及作业空间的调研,提出了适合本工程的扩大板式基础托换以及盾构机直接切桩的施工方案。为了确保在桩基托换及刀盘切桩施工过程中桥梁结构的安全性和正常通行功能的发挥,通过理论分析和数值计算等手段,对桩基托换施工过程中桩基合理开挖暴露长度、桩—筏体系受力转换机理以及盾构切桩对上部结构的影响进行了研究。研究结果表明:地基加固及扩大板式基础托换法能够有效减小施工期间桥梁的沉降、改善桥梁结构的受力性态;由于原桩基承担荷载大都转移到托换后的筏板基础上,因此部分桩基的切除对桥梁结构的安全性影响不大;现场监测结果表明,施工过程中桥梁结构的沉降变形与计算结果吻合较好,说明本工程的方案制定合理、施工措施得当,桥梁结构处于安全范围之内。During the construction of Shanghai Metro line No. 10, the interval tunnel from Liyang Road Station to Quyang Road Station has to pass through the pile foundation of Shajinggang Bridge on Siping Road. Based on the survey of the existing bridge structure, surrounding environment, construction condition and working space, a proper construction scheme including pile underpinning with expanded raft and cutting pile directly with shield machine is proposed. In order to ensure the safety of bridge structure and the normal traffic capacity during the construction process, by means of the theoretical analysis and numerical simulation, the studies are carried out on reasonable excavation length of pile, load transfer mechanism of pile-raft system and the construction influence on bridge structure due to cutting pile, etc. The results show that the soil reinforcement and pile-raft underpinning can effectively reduce bridge settlement and improve the bridge loading state. Secondly, since the original load born by piles is mainly transferred to raft foundation, the residual part of the pile to be cut has little effect on the security of bridge structure. According to the field monitoring results, the settlement of bridge structure during the construction process is in good accordance with the calculated results, which indicates that the construction scheme is reasonable, the construction measures are appropriate and the bridge structure is in the allowable safety range.

关 键 词：软土 盾构隧道 桥梁 桩基托换 筏板基础 地基加固 

分 类 号：TU473[建筑科学—结构工程]