基于桥桩保护的带撑双排桩基坑支护实例及有限元分析

Case and finite element analyses of foundation pit structure of double-row piles with brace based on bridge pile protection

基坑施工会引起邻近桥桩产生附加变形,变形过大则可能影响桥梁正常使用,此时基坑支护方案的确定还应基于桥桩保护的需求。某市政道路箱涵基坑下穿市域铁路桥梁,为控制基坑变形对桥梁基础的影响,采用了双排桩结合两道内支撑和坑内地基土加固的支护方案。现场实测结果表明,基坑和邻近桥桩的变形控制效果较好。对该实例进行有限元模拟,实测数据与数值模拟结果基本一致,验证了有限元模型的可行性,接着分析了有无支撑、支撑间距以及排桩间距对围护结构及桥桩变形的影响。

Foundation pit construction can cause additional deformation of adjacent bridge piles,and excessive deformation may affect the normal use of the bridge.The determination of foundation pit support scheme should therefore be based on the needs of bridge pile protection.This paper uses a box culvert foundation pit for municipal road that goes under the municipal railway bridge in order to control the influence of foundation pit deformation on bridge foundation.The supporting scheme of double-row piles,two internal supports,and foundation soil reinforcement in the pit are adopted.The field measurement results showed that the deformation control effect of foundation pit and adjacent bridge piles is reasonable.The finite element simulation is carried out.The measured data is consistent with the numerical simulation results,which verifies the feasibility of the finite element model.The influence of self-sustaining,support spacing and row pile spacing on the deformation of retaining structure and bridge pile were analyzed.