黏土地层盾构隧道开挖面失稳离心试验及数值模拟  

Centrifuge Model Test and Numerical Simulation of Face Instability of Shield Tunnel in Clay

作　　者：雷华阳[1,2] 刘敏[1] 钟海晨 许英刚 袁大军[3] Lei Huayang;Liu Min;Zhong Haichen;Xu Yinggang;Yuan Dajun(School of Civil Engineering,Tianjin University,Tianjin 300354,China;Binhai Key Laboratory of Civil Engineering Structure and Safety,Ministry of Education,Tianjin 300354,China;School of Civil Engineering,Beijing Jiaotong University,Beijing 100091,China)

机构地区：[1]天津大学建筑工程学院,天津300354 [2]滨海土木工程结构与安全教育部重点实验室,天津300354 [3]北京交通大学土木建筑工程学院,北京100091

出　　处：《天津大学学报（自然科学与工程技术版）》2023年第5期503-512,共10页Journal of Tianjin University：Science and Technology

基　　金：国家重点研发计划资助项目(2017YFC0805402);国家自然科学基金资助项目(52078334).

摘　　要：通过开展离心模型试验和数值模拟,对黏土地层中盾构隧道开挖面的失稳破坏特征进行了研究.通过开挖面支护力-开挖面板后退位移关系曲线,获得了开挖面支护力呈快、缓和稳的3阶段变化特征,开挖面支护力-位移曲线中未呈现支护力反弹现象,比对应砂土地层更慢达到极限值,极限支护力值为5%~7%初始竖向土压力.地表沉降在开挖面失稳过程持续增加;埋深比为1.0时,横向地表沉降槽形状变化明显.在隧道中心轴线高度处,纵向土压力沿纵向随远离隧道截面距离逐渐增大,纵向土拱率值逐渐增大,且远小于对应竖向土拱率值.根据盾构开挖面失稳过程中竖向土压力沿深度变化曲线、纵向土压力沿掘进方向变化曲线,以及横向土压力沿横向变化曲线的拐点可得到失稳松动区和扰动区的范围.埋深比为1.0时,在隧道中心轴线水平面内隧道截面前方0.5D以外区域,纵向土压力和横向土压力的变化比竖向土压力更加显著.相比传统开挖面失稳分析中仅对竖向土压力变化规律进行的研究,提出应同时研究三向土压力的时空变化规律.The face collapse characteristics of shield tunnel in clay were studied via centrifugal model tests and numerical simulations.The relationship between the supporting pressure and the excavation face displacement was obtained.The face supporting pressures during the face instability process followed three stages,i.e.,rapidly decreasing,slowly decreasing,and stabilization.No rebound occurred in this case while it was observed in the sandy soil,and the required retreat displacement of the face excavation panel to attain the limit value was larger than that of the sandy soil.The limit supporting pressure was 5%—7%of the initial overburden pressure.The surface settlement kept increasing during the overall face instability process.The shape of the transversal trough of the surface settlement changed clearly when C/D=1.0.The longitudinal earth pressure increased with the increasing distance away from the tunnel along the longitudinal direction at the height of the central axis of the shield tunnel.The longitudinal earth pressure concentration ratio increased but was considerably lesser than the corresponding vertical earth pressure concentra tion ratio.The loose zone and disturbed zone scopes were obtained from the curves of the vertical,longitudinal,and transversal earth pressures in relation to the depth,the direction of shield tunneling,and the transversal direction,respectively.The longitudinal and transverse earth pressures changed more considerably than the vertical earth pressure in the scope out of the 0.5D range from the tunnel’s central axis.The results showed that in addition to the vertical earth pressure targeted in the traditional method,the influence of the spatiotemporal changes of the longitudinal and transversal earth pressures should be comprehensively considered in the research studies about the face stability shield tunnels.

关 键 词：盾构隧道 开挖面失稳 离心模型试验 数值模拟 黏土 

分 类 号：U45[建筑科学—桥梁与隧道工程]