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Stability Analysis of Tunnels under Horizontal and Vertical Joint Developments
1 Shanghai Tong Yan Civil Engineering Ltd 2 Inner Mongolia Transport Design and Research Institute 3 College of Surveying and Geo-Informatics, Tongji University
Abstract In this paper, based on the construction of the Yaogou tunnel in Hohhot, the characteristic parameters of approximate horizontal and vertical developed joints are collected for areas of the typical section; additionally, the kinematic behaviors and force characteristics of the overlaying rock are analyzed and the deformation and instability patterns of the surrounding rock are studied by adopting field monitoring, a laboratory model test and numerical simulation. The results show that: 1) without support, the stability of the strata is very poor during construction with the caving and loosening zones concentrated above the vault, of which the maximum caving height is 0.48 times the tunnel width, the caving area is 0.51 times the section area, the equivalent load of the vault is 0.084 MPa and the loosening zone extends to the ground surface in an almost triangular distribution; and 2) with a primary lining, the loosening range of the strata is significantly reduced, with a maximum caving height of 1.1 times the tunnel width, and the maximum settlement of the vault is reduced to 7.7 mm and the sidewall convergence becomes 3.4 mm.
Abstract：
In this paper, based on the construction of the Yaogou tunnel in Hohhot, the characteristic parameters of approximate horizontal and vertical developed joints are collected for areas of the typical section; additionally, the kinematic behaviors and force characteristics of the overlaying rock are analyzed and the deformation and instability patterns of the surrounding rock are studied by adopting field monitoring, a laboratory model test and numerical simulation. The results show that: 1) without support, the stability of the strata is very poor during construction with the caving and loosening zones concentrated above the vault, of which the maximum caving height is 0.48 times the tunnel width, the caving area is 0.51 times the section area, the equivalent load of the vault is 0.084 MPa and the loosening zone extends to the ground surface in an almost triangular distribution; and 2) with a primary lining, the loosening range of the strata is significantly reduced, with a maximum caving height of 1.1 times the tunnel width, and the maximum settlement of the vault is reduced to 7.7 mm and the sidewall convergence becomes 3.4 mm.
2015, Vol. 52 