软土地区地面堆载对桥梁下部结构的影响分析

Analysis of Influence of Ground Loading on Bridge Substructure in Soft SoilArea

以地面堆载导致的某软土地区匝道桥病害为背景,采用有限元软件Midas GTS NX建立三维数值计算模型,分析了土体堆载对桥梁基础沉降及侧移的影响,并与实测结果进行比较,得到软土地区地面堆载对既有结构变形的影响规律。分析表明,在地质条件多为粉土、黏土的软土地区,大面积堆载将会使既有桥墩基础产生过大的沉降和侧移,且侧移量往往更大。以桥墩承台侧移量为指标拟定桩基础加固与否的评判标准,并依据评判标准制定桥墩立柱及基础的加固方案,提出多点同步顶推方法进行主梁纠偏复位及支座更换,解决了该桥病害及修复难题。

Excessive ground loading can cause ramp bridge defects in a soft soil area.To analyze the interaction pattern between ground loading and existing structural deformation,a three-dimensional finite element model was established using the commercial software,Midas GTS NX.The numerical calculation can model soil loading's effect on the bridge foundation's settlement and lateral displacement.The simulated results were comparable with the measured ones.It shows that,heavy ground loading in soft soil area with widespread silt and clay will cause excessive settlement of the existing bridge pier foundation.Meanwhile,the lateral displacement tends to be enlarged.The lateral displacement of pier cap can be taken as an indicator to assess the structure's health status,leading to the potential reinforcement scheme of the pier column and foundation.Aiming at the maintenance and correction of bridge's defect,a synchronous multi-point pushing method was proposed which can adjust the main beams and replace the supports.