Mechanism of Large Deformation and Active Control Technology of Yuelongmen Tunnel with High Geostress and Soft Rock
This article focuses on the problems of large deformation and difficult support in high geostress soft rock tunnels.Taking the Yuelongmen Tunnel as the engineering background,the deformation and damage characteristics of the tunnel and the cause mechanism of large deformation were analysed through on-site investigation,and it was concluded that the high ground stress,soft and weak rock layer,engineering disturbance and groundwater and other factors led to large deformation and damage of the tunnel surrounding rock.Based on the concept of active control technology,the control measures of"optimising contour,combining short and long lengths,reinforcing the surrounding rock,double-layer support,step-by-step reservation and rapid closure"were proposed.Field practice results show that,after adopting the active control technology,the maximum vault settlement and arch waist convergence values of the tunnel are 211 mm and 172 mm respectively,and the maximum vault settlement and arch waist convergence rates are 6.9 mm/d and 5.7 mm/d respectively,which verifies the applicability of the support scheme.
high geostresssoft rock tunnelYuelongmen Tunnellarge deformationactive control technology
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