西安地铁穿越地裂缝段隧道“先盾后扩”施工地表沉降规律  

Ground Surface Settlement Laws of Xi’an Subway Tunnel Passing Through Ground Fissures Constructed by“Shield Before Expansion”Method

作　　者：王睿 何朝君 朱元伟 WANG Rui;HE Chaojun;ZHU Yuanwei(Guangzhou Metro Design&Research Institute Co.Ltd.,Guangzhou 510010,China;School of Highway,Chang’an University,Xi’an 710064,China)

机构地区：[1]广州地铁设计研究院股份有限公司,广州510010 [2]长安大学公路学院,西安710064

出　　处：《铁道建筑》2023年第12期6-10,共5页Railway Engineering

基　　金：西安市轨道交通集团有限公司科技项目(D15-YJ-152021006);广州地铁设计研究院股份有限公司科技项目(KY-2020-003)。

摘　　要：通过数值模拟分析了西安地铁15号线府君庙村站—祝村站区间隧道采用“先盾后扩”法施工时地表沉降规律,并通过回归分析给出了沉降槽宽度系数(K)和地层损失率(V)取值。结果表明:采用“先盾后扩”法施工时扩挖阶段地表沉降约占最终地表累计沉降的2/3,地表横向沉降曲线总体服从Peck公式给出的沉降槽形态;该工法下K值在[0.45~0.55)区间占比高达76.7%,平均值0.50,略高于西安地区不同地层中地铁隧道施工平均值(0.45)、西安地铁隧道盾构法平均值(0.421)和交叉中隔壁(Cross Diaphragm,CRD)法平均值(0.467);该工法下V值在0.996%~1.401%,平均值1.190%,与西安地区不同地层中地铁施工平均值(1.170%)接近,高于西安地区盾构法平均值(0.735%),低于西安地区CRD法平均值(1.315%);首环管片扩挖会改变盾构隧道边界条件和向下挠曲形态,进而引发地层沉降突然增大,须要引起重视。The ground surface settlement law of the Fujunmiaocun Station-Zhucun Station section tunnel of Xi’an Subway Line 15 during construction using the“shield before expansion”method was analyzed through numerical simulation,and the values of the settlement groove width coefficient(K)and the formation loss rate(V)were given through regression analysis.The results show that when using the“shield before expansion”method for construction,the ground surface settlement during the excavation stage accounts for about two-thirds of the final cumulative ground surface settlement,and the overall surface lateral settlement curve follows the settlement groove shape given by the Peck formula.the proportion of K value under this construction method,in the range of[0.45~0.55)is as high as 76.7%,with an average value of 0.50,slightly higher than the average value(0.45)of subway construction in different strata in Xi’an,the average value(0.421)of shield tunneling method in Xi’an,and the average value(0.467)of cross diaphragm(CRD)method.The V value under this construction method ranges from 0.996%to 1.401%,with an average value of 1.190%,which is close to the average value(1.170%)of subway construction in different strata in Xi’an,higher than the average value(0.735%)of shield tunneling method in Xi’an,and lower than the average value(1.315%)of CRD method in Xi’an.Expansion excavation of the first ring pipe segment will change the boundary conditions and downward bending shape of shield tunnels,causing a sudden increase in stratum settlement,which needs to be taken seriously.

关 键 词：地铁隧道 地表沉降 先盾后扩 西安地裂缝 沉降槽宽度系数 地层损失率 

分 类 号：U455.4[建筑科学—桥梁与隧道工程]