面向地表沉降控制的地铁盾构参数研究

摘要

The settlement of the ground surface is one of the most concerned engineering problems in subway shield tunneling,because the settlement is in relation to the usual operation of adjacent structures and the normal proceeding of shield construction.Therefore,this paper takes the ground surface settlement as the key objective to decide the shield parameters.The parameters affecting the surface settlement are simplified into two indices,namely support pressure ratio on the tunnel face to the earth pressure and the elastic modulus of generation layer.Taking the section from Nanmenkou to Houjiatang along Line 1 of Changsha Metro as an example,this paper carries out FLAC3D numerical simulation to analyze the effects of the two indices on surface subsidence.The suggestion of the shield parameter values for the selected section of Changsha subway is then put forward.Besides,the subsiding area and the maximum of the subsidence are also proposed.This research brings out a reference for the subsequent construction of Changsha metro and provides a method for parameter deciding of shield tunneling in other cities.%地表沉降是地铁盾构施工过程中最关心的工程问题之一,关乎近邻建筑物能否正常运营及盾构能否正常施工.故本文以地表沉降为关键目标进行地铁盾构参数研究.将影响地表沉降的盾构参数概括为开挖面支护压力比和等代层弹性模量.在此基础上,以长沙地铁1号线南门口一侯家塘区间为工程背景,采用FLAC3D软件对不同盾构参数下的施工过程进行数值模拟,分析了开挖面支护压力比及等代层弹性模量对地表沉降的影响,提出了研究区段的盾构参数建议值.研究同时得出了在建议盾构参数下,研究区段发生地表沉降的范围及地表沉降最大值.为长沙地铁后续建设及其他城市地铁建设盾构参数的选取提供理论依据和方法参考.