深基坑开挖对既有混凝土桥梁桩基影响模拟分析

Analysis on concrete bridge piles due to adjacent excavation using finite element method

基坑开挖引起的大变形会影响到坑附近建筑物的安全性,在基坑设计过程中,必须要考虑基坑开挖对其周围已有建筑物的影响。以沈阳地铁十号线中的某一深基坑工程为背景,应用大型有限元程序ABAQUS对每一步开挖过程后坑外地表沉降进行分析,评价旋喷桩的加固效果。通过对比分析坑外附近桥桩的内力状态来确定旋喷桩的合理长度和合理布置位置。设置旋喷桩可有效减小基坑开挖引起的坑边桥桩的沉降量;同时与未设置旋喷桩的工况相比,设置旋喷桩可以有效的减小邻近桥桩的内力,加固的效果与旋喷桩的桩长和布置位置有关。三维有限元分析对于地铁站开挖模拟是一种适合的途径,并且可以为未来的深基坑设计提供一定的参考。

The large deformation of buildings nearby during excavation can influence the safety of buildings.Hence,this kinds of influence during excavation must be considered in the process of designing.Taking a deep excavation of the Shenyang-metro line 10 as the engineering background,the ground surface settlement outside the excavation in each excavation step is studied as the strengthening effects of rotating-spouting piles by using the large-scale FEM program ABAQUS.The most reasonable length and location of rotating-spouting piles are selected by contrast analysis of the different internal force situation of the bridge pile closed to the excavation.The results show that installing of rotating-spouting piles is an effective way to reduce the settlement of bridge piles due to the excavation.At the same time, compared with the condition without rotating-spouting,installing of rotating-spouting piles can decrease the internal force of the nearby bridge piles.The reinforcement effect is bound up with the length and location of rotating-spouting piles.Three-dimensional finite element method is suitable for the simulation of subway-station excavation process and can provide some references to the future deep excavation design.