The Supporting Mechanism And Stability Of The Surrounding Rock During Skew Horizontal Adit Tunnel Construction Between Near-by Tunnels

The large-scale skew horizontal adit tunnel between near-by parallel tunnels has the function of assisting construction,fire protection and rescue.Repetitious disturbances of construction process at the intersection of the horizontal adit tunnel and parallel tunnels case surrounding rock to crack.And the stress and deformation of surrounding rock become complicated and variable,which is the key about controlling the stability of the tunnel.Accordingly,relying on the Xinling tunnel project in Hangjinqu expressway of Zhejiang provincial,for studying the behavior features of the intersection part of the new tunnel and skew horizontal adit tunnel such as microcosmic failure mechanism,support mechanism and surrounding rock stability,the analytical investigation has been conducted with the synthetic method combining with theoretical analysis,simulating calculation and monitoring in situ.(1)Based on the investigation about the applicability of several kinds of rock strength criterion such as Mohr-Coulomb,Drucker-Prager and Hoek-Brown,this thesis selected appropriate strength criterion in the analysis of cracked surrounding rock of the intersection part.(2)According to the investigation about anchor-spray-injection supporting mechanism,this thesis selected the rational support form and analyzed the evolvement rule on the stress and displacement of surrounding rock of the intersection part.And the influence on the main tunnel due to the skew horizontal adit tunnel excavation was clarified.(3)The influence of the stress characteristics of surrounding rock and support structure duo to the intersection angle was summarized by the dynamic simulation about the stress and displacement of surrounding rock of the intersection part affected in role of different intersection angle.(4)Due to the discreteness of the monitoring data about vault settlement and peripheral convergence of surrounding rock in the intersection part,the law of convergence deformation of tunnel was predicted by the nonlinear regression method.And the contrastive analysis on the applicability of fitting functions was conducted.The research results can provide certain reference and theoretical value for analysis of the stability of surrounding rock of skew horizontal adit tunnel construction project between near-by tunnels.