Improper selection of construction methods or construction control measures during construction in bedding biased strata at shallow buried section of tunnel portal will easily lead to bedding sliding deformation of be...Improper selection of construction methods or construction control measures during construction in bedding biased strata at shallow buried section of tunnel portal will easily lead to bedding sliding deformation of bedding biased strata and development to the surface, which will lead to deformation and cracking of initial tunnel support, distortion of steel frame, and even collapse and roof caving accident in serious cases. Taking a railway tunnel as an example, this paper analyzes the root cause and construction inducement of the tunnels initial branch deformation cracking, surface cracking and spalling surface cracking when the light-dark junction faces vertically. Considering the influence of precipitation in tunnel site area, the state and development trend of surrounding rock pressure and structural deformation are accurately judged through monitoring and measurement data analysis, and the deformation control measures and application timing are determined based on this. The effectiveness of emergency treatment measures for earth-filling back pressure in the tunnel, surface grouting reinforcement and permanent treatment measures for reinforcing locking feet in the tunnel are verified, which ensure the smooth progress of initial support changing arch and heading face excavation. The research process, ideas and methods can be used for reference for similar engineering design and construction.展开更多
文摘Improper selection of construction methods or construction control measures during construction in bedding biased strata at shallow buried section of tunnel portal will easily lead to bedding sliding deformation of bedding biased strata and development to the surface, which will lead to deformation and cracking of initial tunnel support, distortion of steel frame, and even collapse and roof caving accident in serious cases. Taking a railway tunnel as an example, this paper analyzes the root cause and construction inducement of the tunnels initial branch deformation cracking, surface cracking and spalling surface cracking when the light-dark junction faces vertically. Considering the influence of precipitation in tunnel site area, the state and development trend of surrounding rock pressure and structural deformation are accurately judged through monitoring and measurement data analysis, and the deformation control measures and application timing are determined based on this. The effectiveness of emergency treatment measures for earth-filling back pressure in the tunnel, surface grouting reinforcement and permanent treatment measures for reinforcing locking feet in the tunnel are verified, which ensure the smooth progress of initial support changing arch and heading face excavation. The research process, ideas and methods can be used for reference for similar engineering design and construction.
