三洞盾构开挖顺序对地表沉降和管片变形影响  

Effect of Excavation Sequence on Surface Settlement and Segment Deformation of Treble-Hole Shield Tunnel

作　　者：汪优[1] 赵晓薇 代芳 钟明 张恒 Wang You;Zhao Xiaowei;Dai Fang;Zhong Ming;Zhang Heng(School of Civil Engineering,Central South University,Changsha 410075,P.R.China;Power China,Zhongnan engineering Co.,Ltd.,Changsha 410021,P.R.China;China Railway(Shanghai)Investment Group Co.,Ltd.,Shanghai 200126,P.R.China;China Railway ERJU 5th Engineering Co.,Ltd.,Chengdu 610091,P.R.China)

机构地区：[1]中南大学土木工程学院,长沙410075 [2]中国电建集团中南勘测设计研究院有限公司,长沙410021 [3]中铁(上海)投资集团有限公司,上海200126 [4]中铁二局第五工程有限公司,成都610091

出　　处：《地下空间与工程学报》2023年第5期1665-1677,共13页Chinese Journal of Underground Space and Engineering

基　　金：国家自然科学基金(51778633,51308552)。

摘　　要：为探究三洞盾构隧道的开挖顺序对地表沉降和管片收敛产生的影响,本文以南通地铁1号线隧道建设为工程背景,采用FLAC3D软件模拟三洞并行盾构隧道在“右-中-左”“中-右-左”和“左-右-中”3种工况下的掘进过程,分析其引起的地表变形规律及先行洞管片变形规律。对于地表变形规律,研究发现,不同开挖顺序引起的沉降槽宽度基本相同,但引起的地表最大沉降值存在差异,3种工况引起的地表沉降由大至小排序为:工况2>工况1≈工况3。对于管片变形规律,不同开挖顺序引起的隧道变形均由标准的圆形变为上下扁、两端宽的椭圆形,但偏移过程及最终管片收敛值存在差异,3种工况引起的先行隧道变形由大至小排列为:工况3>工况2≈工况1。数值模拟结果表明当采用工况1“右-中-左”施工顺序,即3条隧道依次顺序施工时,引起的地表最大沉降值和管片收敛偏移值较小,能够有效保障隧道施工安全,建议在实际施工过程中优先选择该开挖顺序。数值模拟得到的最大沉降值为-11.8 mm,通过Peck公式预测的最大沉降值为-11.1 mm,与实测拟合数据拟合得到最大沉降值-11.63 mm相比误差分别为1.46%和4.78%。In order to investigate the influence of excavation sequence of three-line parallel shield tunnel on ground surface settlement and segment deformation,teking the tunnel construction of Nantong Metro Line 1 as the engineering background,FLAC3D software is used to simulate the tunneling process of three-line parallel shield tunnel under three cases of"right-center-left","center-right-left"and"left-right-center",and the deformation pattern of the ground surface and shield segment is analysed.For the ground surface deformation,it is found that the width of the settlement trough is basically the same,but there are differences in the maximum surface settlement values.The order of surface subsidence caused by the three cases is as follows:Case 2>Case 1≈Case 3.For the segment deformation,the tunnel deformation is changed from a standard circle to an ellipse with flat top and bottom and wide ends,but there are differences in the offset process and the final segment convergence value.The segment deformation of the antecedent tunnel caused by the three case is arranged in descending order:Case 3>Case 2≈Case 1.Numerical simulation results show that when the"right-center-left"construction sequence is used,the maximum ground surface settlement and segment deformation is smaller,which can effectively guarantee the safety of tunnel construction.It is recommended to choose this excavation sequence in the actual construction process.The maximum settlement value obtained from the simulation was-11.8 mm,and the maximum settlement value predicted by the Peck formula was-11.1 mm,with errors of 1.46%and 4.78%,respectively,compared with the maximum settlement value of-11.63 mm obtained by fitting the measured fitting data.

关 键 词：三洞盾构隧道 开挖顺序优化 数值模拟 地表沉降 管片收敛 

分 类 号：U455.43[建筑科学—桥梁与隧道工程]