复杂条件下深基坑围护结构变形演化规律研究  

Research on deformation evolution law of retaining structure of deep foundation pit under complex conditions

作　　者：麻凤海[1] 陈霞[1] 刘增斌 MA Feng-hai;CHEN Xia;LIU Zeng-bin(College of Architectural and Engineering, Dalian University, Dalian 116622, China)

机构地区：[1]大连大学建筑工程学院,辽宁大连116622

出　　处：《广西大学学报（自然科学版）》2020年第4期723-731,共9页Journal of Guangxi University（Natural Science Edition）

基　　金：国家自然科学基金资助项目(51474045,51174038)。

摘　　要：为了研究土体开挖卸荷扰动的条件下,围护结构水平位移的变化规律,以沈阳市地下综合管廊(南运河段)5号盾构始发井深基坑工程为背景,采用MIDAS\\GTS大型有限元软件建立了深基坑三维地层模型,对基坑施工的全过程进行全面、动态的模拟,计算得出了围护结构在各开挖步后的位移云图和变形曲线,并将数值计算结果与监测数据进行对比分析。研究结果表明:①围护结构的水平侧移具有显著的角部效应,影响范围约为基坑开挖深度的2.5~3.0倍,在基坑角部附近较小,而后呈逐渐增大的趋势;②围护结构的水平侧向位移对基坑整体稳定有重要意义,钢支撑的架设能够有效限制基坑向内变形;③数值计算与实测数据有较好地吻合,平均误差为10%,且计算值偏小;④基坑长边和短边的最大位移值均在开挖结束后,短边最大水平位移值为10.8 mm,长边最大位移值为16.7 mm,小于警戒值25 mm。In order to study the variation law of the lateral displacement of the retaining structure under the condition of excavation and unloading disturbance of soil,this paper takes the deep foundation pit project of the No.5 shield starting shaft of the underground comprehensive pipeline corridor(south canal section)in Shenyang as the background,and uses the MIDAS\GTS large-scale finite element software to establish a three-dimensional formation model of the deep foundation pit.This model is used to carry out a comprehensive and dynamic simulation of the whole process of foundation pit construction.The software calculates the displacement cloud diagram and deformation curve of the retaining structure after each excavation step,and compares the numerical calculation results with the monitoring data.The research results show that:①the lateral displacement of the retaining structure has a significant corner effect.The impact range is about 2.5 to 3.0 times the excavation depth of the foundation pit,which is small near the corner of the foundation pit,and then gradually increases;②the lateral displacement of the retaining structure is of great significance to the overall stability of the foundation pit,and the erection of steel supports can effectively limit the inward deformation of the foundation pit;③the numerical calculation is in good agreement with the monitoring data.The average error is 10%,and the calculated value is relatively small;④The maximum displacement values of the long side and the short side in the foundation pit appear after the excavation.The maximum lateral displacement of the short side is 10.8 mm,and the maximum displacement of the long side is 16.7 mm,which are less than the warning value of 25 mm.

关 键 词：深基坑 有限元 围护结构 水平变形 监测 

分 类 号：TU473[建筑科学—结构工程]