摘要
为探讨对向施工隧道贯通前开挖面存在的相互影响对地层稳定性的变化规律,本文将该问题假定为沿隧道纵向中线剖开的二维平面应变模型,采用刚体平动运动单元上限有限元法开展计算分析,获得了土体自重作用下地层临界失稳状态对应的隧道开挖面稳定性系数Ncr和有效间断线网破坏模式,以单元速度云图和速度矢量图形式呈现了典型破坏模式下速度场分布的特征。研究发现:对向开挖面间距比S/D对稳定性系数Ncr有显著影响,隧道埋深比H/D和土体内摩擦角Ф对其亦有影响。在转换间距比Str/D附近,稳定系数Ncr值差别不大,但破坏模式形态和范围差异明显。本研究为对向施工隧道贯通前的稳定性评价、选取合理预加固方案等工作提供理论支撑。
To investigate the stability change rule of the mutual influence of opposite direction excavation faces before penetration,in this study,the issue is simplified conservatively into the two-dimensional plane strain model along the longitudinal middle line of a tunnel.Using the upper bound finite element method with rigid translatory moving elements,a series of stability coefficients N cr and collapse mechanisms displayed with active discontinuities under the critical instability state of formation is obtained considering the soil self-weight.The velocity field distribution characteristics of the typical failure mechanisms are displayed using the unit velocity cloud map and velocity vector figure.The research determined that the dimensionless distance ratio S/D of opposite direction excavation faces has a significant influence on the stability coefficients Ncr.Moreover,the dimensionless buried depth ratio H/D of the tunnel and the internal friction angleФin the soil also has an influence on the stability coefficients Ncr.Near the transition spacing Str/D,a slight difference in the Ncr value is observed,whereas obvious differences in the form and scope of the damage are detected.The conclusions provide theoretical support for the stability evaluation of tunnel faces on the opposite side before penetration and the selection of reasonable pre-reinforcement of stratum.
作者
孙雁军
阳军生
杨峰
罗静静
SUN Yanjun;YANG Junsheng;YANG Feng;LUO Jingjing(School of Civil Engineering,Central South University,Changsha 410075,China;Hu′nan Expressway Construction and Development Co.,Ltd.,Changsha 410001,China;Key Laboratory of Engineering Structure of Heavy Railway,Ministry of Education,Central South University,Changsha 410075,China)
出处
《哈尔滨工程大学学报》
EI
CAS
CSCD
北大核心
2019年第7期1290-1296,共7页
Journal of Harbin Engineering University
基金
国家自然科学基金项目(51878669)
关键词
对向施工
开挖面稳定性
上限有限元
刚体平动运动单元
稳定性系数
破坏模式
隧道
opposite construction
tunnel face stability
upper bound finite element
rigid translatory moving elements
stability factor
failure mechanism
tunnel
