双线盾构施工穿越对上部框架结构影响有限元分析

Finite Element Analysis of the Influence of Double Shield Tunneling On the Upper Frame Structure

为研究盾构开挖对框架结构的影响,以合肥市某5层框架结构为研究对象,考虑上部结构-桩基-土体的共同作用。采用有限元软件ABAQUS建立了盾构隧道、土体、桩基、上部框架的整体三维有限元模型,结合实际监测数据计算分析了双线盾构施工穿越框架结构的影响。有限元计算结果表明:随着框架结构层数的增加,框架中柱Z2的x方向倾斜度逐渐变大,而随着盾构的掘进Z2的x方向倾斜度先增大后减小。框架中柱Z2的y方向倾斜度逐渐变大,而随着左右双线盾构分别通过Z2下方时Z2的x、y方向倾斜度极大。并结合开挖之前的监测数据与有限模拟结果预测了基础总最大整体倾斜为0.61‰、最大相邻柱基沉降差为0.0011L。两指标均未超《建筑地基基础设计规范》(GB50007-2011)关于同类建筑基础变形的限值(4‰及0.002L)。

In order to study the effect of shield excavation on the frame structure,a five-story frame structure in Hefei City was taken as the research object,and the joint action of the superstructure-pile-soil was considered. The finite element software ABAQUS was used to establish the integral 3D finite element model of the shield tunnel,soil,pile foundation and upper frame. The effect of the double shield tunneling across the frame structure was calculated and analyzed with the actual monitoring data. The finite element calculation results show that with the increase of the number of frame structures,the inclination of the Z2 column in the frame gradually increases in the x direction,while the slope of the Z2 in the frame increases first and then decreases. The inclination of the y-direction of the column Z2 in the frame gradually becomes larger,and the inclination of the Z2 in the x- and y-directions is extremely large as the left and right double-line shield passes through the lower portion of Z2,respectively. Combined with monitoring data and finite simulation results before excavation,the overall maximum total tilt of the foundation is estimated to be 0.61‰,and the maximum difference between the adjacent column foundations is 0.0011 L. Both indicators have not exceeded the limits of the basic deformation of similar buildings (4‰and 0.002 L) in the “Code for the Design of Foundations of Building Foundations”(GB50007-2011).