【摘要】 采用三维数值模拟的方法,对新建桥梁的钻孔灌注桩的施工工程进行计算,预测了其在各步序施工条件下对周围土体应力和变形的影响,并对各施工步序对邻近桩基应力变形的影响进行了分析。结果表明:(1)新建桥台的施工,对既有桥桩的位移和既有桥桩结构的应力有一定影响;(2)各个施工步序对地层应力位移影响较大,基坑下部土体挤入较为严重,特别是靠近既有桥桩的基坑下部挤入值较大;(3)其中第1施工步序和第3施工步序对既有桥桩的应力影响相对于其他步骤较大;(4)在考虑桩基施工对周围土体扰动的情况下,桩基施工对既有桥桩的沉降影响不大。施工建议为:(1)第1施工步序和第3施工步序是核心风险源,需要特别注意施工安全风险;(2)对既有桥桩结构周围土体进行注浆加固;(3)在允许的情况下,提高挡土墙结构和横撑的强度;(4)建立监测预警系统,进行信息化管理。更多还原

【Abstract】 Based on the construction engineering of bored cast-in-place piles of a new bridge,by using FEM simulation,the influence of surrounding soil stress and deformation under step construction condition is predicted,and the influence of steps of the construction sequence on stress deformation of adjacent piles are analysed.The result shows that(1) new abutment construction has a certain influence on the displacement and the structure stress of the existing bridge piles;(2) the influence of construction steps on stress and displacement of stratum is strong,the squeezing of lower part of foundation pit soil is remarkable,particularly the squeezing value near the lower part of existing bridge piles is larger;(3) the effect of the first step and the third step of construction on the stress of existing bridge piles is relatively larger to the other steps;(4) in consideration of disturbance of pile foundation construction process on the surrounding soil,pile foundation construction has little effect on the settlement of existing bridge piles.It is suggested that(1) the first step and third step is the core source of risk,which need to be paid special attention to construction safety risk;(2) to grout the surrounding soil of existing bridge piles;(3)to improve the strength of retaining wall structure and transverse braces in the allowed circumstance;(4) to build monitoring and warning system for information management.更多还原