盾构掘进施工对既有基坑影响的理论分析  

Analysis on lateral additional loads on adjacent foundation pit induced by shield advancing

作　　者：卢卓 魏焕卫[1] LU Zhuo;WEI Huanwei(School of Civil Engineering,Shandong Jianzhu University,Jinan 250101,China)

机构地区：[1]山东建筑大学土木工程学院

出　　处：《山东建筑大学学报》2019年第4期43-49,共7页Journal of Shandong Jianzhu University

基　　金：山东建筑大学横向课题项目(山东电力工程咨询院有限公司K22014016)

摘　　要：盾构掘进邻近既有基坑时,盾构施工的附加应力会对基坑产生影响,对其进行分析,可以为临近既有基坑时盾构掘进施工提供参考。文章基于Mindlin应力解与Sagaseta基本解,推导了有关盾构掌子面推力fs、盾壳摩阻力fm和盾构与开挖面的间隙引起的土体损失Vloss作用在支护结构上的附加应力荷载和应力的解析解,并将计算结果与实测数据进行对比。结果表明:沿盾构掘进方向,公式求解计算的附加应力值与实测数据在掌子面前(x>0)相似度较高,实测数据最大值出现在掌子面位置(x=0),而计算结果的最大值出现在掌子面前0.25D位置(x=0.25D);沿掘进方向,在掌子面前可按计算值进行计算,0.25D后附加应力开始减小,附加应力最大值与实测最大值差别不大,可按计算的附加应力最大值对支护结构进行验算;x>1.0D时,fm为支护结构的主要影响因素,而0.25D1.0D时其值很小,可以忽略不计,土体损失产生的附加应力对支护结构的影响发挥次要作用。When shield tunneling is near the existing foundation pit,the additional stress of shield tunneling will affect the supporting structure.The analysis can provide reference for shield tunneling construction near existing foundation pit.This paper makes a theoretical analysis and provides a basis for this condition.Based on the Mindlin stress solution and the fundamental solution,analytical solution of additional stress load and stress of the shield face thrustfs,the shield shell friction resistancefmand the soil loss caused by gap between shield and excavation face(Vloss)on supporting structure.Comparing the calculated results with the measured data,it is found that the calculated additional stress value along the shield tunneling direction formula is similar to the measured data in front of the face(x>0);the maximum value of measured data appears on the palm surface(x=0),the maximum value of the result appears in front of the palm(x=0.25D).When x is greater than 1.0D,fm is the main influencing factor of supporting structure;when x is between 0.75D and 0.25D,fs is the main influencing factor of supporting structure;the additional stress caused by soil loss increases from 1.0D,more than 1.0D is negligible,additional stress caused by soil loss plays a minor role in supporting structure.

关 键 词：盾构 基坑支护 附加应力 MINDLIN应力解 土体损失 

分 类 号：TU443[建筑科学—岩土工程]