Influence of Inverted Arch Over-Excavation on the Structural Stress of Tunnel in Gently Inclined Soft Rock Strata
Based on No.1 Tunnel of Jiuwandashan of Guiyang-Nanning Railway,in order to grasp the influence of over-excavation of tunnel in gently inclined soft rock stratum on structural stress,the field testing technique was used to monitor the typical inverted arch section under two working conditions:(1)after the inverted arch blasting,the arch frame was directly erected and then the concrete was sprayed to form the initial support;(2)after the inverted arch blasting,the over-excavated part of the tunnel was filled by spraying concrete to make the tunnel overarched accurately,then the steel frame was erected to ensure that it adhered closely to the surrounding rock,and then the initial support was formed by spraying concrete.The surrounding rock pressure,steel frame and concrete stress of the inverted arch under two working conditions were tested respectively to analyze the structural stress characteristics of the inverted arch before and after the over-excavation,and to verify the role of the initial spraying process in constructing the tunnel in gently inclined rock stratum with large cross-section.
gentle inclined soft rock stratumtunnel inverted archover-excavationstructural forceinitial supportfield test
NETL
NSTL
万方数据
