摘要
为揭示新建铁路隧道下穿开挖对邻近既有公路隧道的变形影响,以新建金玉顶隧道工程为依托,利用有限元软件建立三维数值模型,分析开挖扰动作用下地表沉降、既有隧道结构变形、新建隧道支护结构和围岩的变形和应力分布规律。结果表明,隧道下穿开挖可能引起既有隧道以沉降为主的附加变形,最大沉降量发生在隧道底部,数值模拟分析结果与现场监测结果吻合度较高。随着开挖的逐步推进,既有隧道墙腰水平线上的垂直应力始终呈现两头大、中间小的槽型分布形式,越接近隧道壁其垂直应力越高。隧道正上方地表纵向沉降呈现从“勺形”到“漏斗形”的变化规律,并最终趋于稳定。基于下穿开挖隧道支护结构和掌子面挤出变形分析结果,结合围岩变形、塑性区发展和应力分布规律,论证了隧道断面设计和支护开挖方式的合理性。
To reveal the deformation impact of newly built railway tunnel excavation beneath an adjacent existing highway tunnel,based on the new Jinyuding tumel project,a three-dimensional numerical model was established using finite element software to analyze the deformation and stress distribution laws of surface settlement,existing tunnel structure deformation,newly built tunnel supporting structure and surrounding rock deformation under excavation disturbance.The results indicate that tunnel excavation beneath an existing tunnel causes additional deformation of the existing tunnel,primarily in the form of settlement,with the maximum settlement occurring at the tunnel bottom,and the numerical simulation results have a high degree of agreement with field monitoring results.As the excavation progresses step by step,the vertical stress on the horizontal line of the existing tunnel′s wall waist always shows a trough-shaped distribution with higher stress at both ends and lower in the middle,and the closer to the tunnel wall,the higher the vertical stress.The longitudinal settlement above the tunnel is characterized by a change from a "spoon-shaped" to a "funnel-shaped" pattern and eventually tends to stabilize.Based on the analysis results of the tunnel support structure and the excavation face squeezing deformation,combined with the deformation of the surrounding rock,the development of the plastic zone,and the pattern of stress distribution,the rationality of the tunnel section design and the excavation and support method is demonstrated.
作者
易俊
余尚军
吴晓攀
肖隆晨
钟先海
黄天明
YI Jun;YU Shang-jun;WU Xiao-pan;XIAO Long-chen;ZHONG Xian-hai;HUANG Tian-ming(Nanchang Railway Engineering Co.,Ltd.,China Railway 24th Bureau Group,Nanchang 330002,China;School of Civil Engineering&Architecture,East China Jiaotong University,Nanchang 330013,China;Center for Jiangxi Province Underground Space Technology Development Engineering Research,Nanchang 330013,China)
出处
《河南城建学院学报》
CAS
2024年第4期65-71,共7页
Journal of Henan University of Urban Construction
基金
国家自然科学基金项目(52208343)。
关键词
隧道下穿
变形控制
既有隧道
数值模拟
全过程分析
undercrossing tunnel
deformation control
existing tunnel
numerical simulation
whole process analysis
