To reveal the deformation impact of newly built railway tunnel excavation beneath an adjacent exist-ing highway tunnel,based on the new Jinyuding tumel project,a three-dimensional numerical model was estab-lished using finite element software to analyze the deformation and stress distribution laws of surface settle-ment,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 tun-nel 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 even-tually 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.
undercrossing tunneldeformation controlexisting tunnelnumerical simulationwhole process a-nalysis
国家科技期刊平台
NSTL
万方数据
