Abstract In order to explore the influence of different buried depths and opening types on the stress and deforma? tion of the main structure when a cross passage is set up between super large diameter shield tunnels, based on the project case of the pedestrian cross passage of the shield section tunnel in Beijing East Sixth Ring Road Reconstruction Project, the stress state, convergence deformation, dislocation between segments and rings and earth pressure around the tunnel opening ring of the shield section tunnel structure are monitored by centrifugal model test to simulate three cases of buried depth, different opening sizes and section types. The results show that: (1) When the centrifugal acceleration reaches the set value, the earth pressure tends to be stable, and the greater the buried depth is,the longer the stabilization time will be required. The soil arching effect exists in the overlying soil of the tunnel, and the greater the buried depth is, the more obvious the soil arching effect will be. (2) The lateral opening of the shield tunnel has a significant impact on the stress of the main structure. The larger the opening size is, the greater the deformation of the structure will be. (3) Under different buried depth cases, the dislocation between segments increases with the increase of centrifugal acceleration, and the increase rate gradually rises. (4) Under different buried depth cases, the stress state on the inside of the main tunnel arch waist is basically the identical, which is compressive stress. The pattern of the stress at the outside of the arch waist is more complex. The compressive stress concentration of the split ring will offset a part of the tensile stress, and the outside of the arch waist of other adjacent rings except the split ring will mainly bear the tensile stress.
Abstract：
In order to explore the influence of different buried depths and opening types on the stress and deforma? tion of the main structure when a cross passage is set up between super large diameter shield tunnels, based on the project case of the pedestrian cross passage of the shield section tunnel in Beijing East Sixth Ring Road Reconstruction Project, the stress state, convergence deformation, dislocation between segments and rings and earth pressure around the tunnel opening ring of the shield section tunnel structure are monitored by centrifugal model test to simulate three cases of buried depth, different opening sizes and section types. The results show that: (1) When the centrifugal acceleration reaches the set value, the earth pressure tends to be stable, and the greater the buried depth is,the longer the stabilization time will be required. The soil arching effect exists in the overlying soil of the tunnel, and the greater the buried depth is, the more obvious the soil arching effect will be. (2) The lateral opening of the shield tunnel has a significant impact on the stress of the main structure. The larger the opening size is, the greater the deformation of the structure will be. (3) Under different buried depth cases, the dislocation between segments increases with the increase of centrifugal acceleration, and the increase rate gradually rises. (4) Under different buried depth cases, the stress state on the inside of the main tunnel arch waist is basically the identical, which is compressive stress. The pattern of the stress at the outside of the arch waist is more complex. The compressive stress concentration of the split ring will offset a part of the tensile stress, and the outside of the arch waist of other adjacent rings except the split ring will mainly bear the tensile stress.
CHEN Rendong1 LU Ping2 SUN Ye1 LIU Minggao1 PANG Kang1
.Centrifuge Model Test of the Cross Passages in Super Large Diameter Shield Tunnels[J] MODERN TUNNELLING TECHNOLOGY, 2022,V59(6): 114-124
2022, Vol. 59 