By combining the results of laboratory model tests with relevant flow rules, the failure mode of shallow unsymmetrical loading tunnels and the corresponding velocity field were established. According to the principle ...By combining the results of laboratory model tests with relevant flow rules, the failure mode of shallow unsymmetrical loading tunnels and the corresponding velocity field were established. According to the principle of virtual power, the upper bound solution for surrounding rock pressure of shallow unsymmetrical loading tunnel was derived and verified by an example. The results indicate that the calculated results of the derived upper bound method for surrounding rock pressure of shallow unsymmetrical loading tunnels are relatively close to those of the existing "code method" and test results, which means that the proposed method is feasible. The current code method underestimates the unsymmetrical loading feature of surrounding rock pressure of shallow unsymmetrical loading tunnels, so it is unsafe; when the burial depth is less or greater than two times of the tunnel span and the unsymmetrical loading angle is less than 45°, the upper bound method or the average value of the results calculated by the upper bound method and code method respectively, is comparatively reasonable. When the burial depth is greater than two times of the tunnel span and the unsymmetrical loading angle is greater than 45°, the code method is more suitable.展开更多
With the increasing traffic demand, the closely built three or more tunnels with large section play a significant role in the tunnel construction. However, the interaction among tunnels has important influences on the...With the increasing traffic demand, the closely built three or more tunnels with large section play a significant role in the tunnel construction. However, the interaction among tunnels has important influences on the security and economy of tunnel engineering, and the calculation of pressure from the surrounding rock during the excavation is one of the problems that need to be solved urgently. Based on the practical engineering of three tunnels, the load model of three tunnels was proposed in consideration of the interaction and excavation sequence between tunnels. In comparison with the load model of single tunnel, the construction mechanical characteristics of the three tunnels were analyzed. The results show that the rock pressure of three tunnels calculated by the current tunnel design code is not reliable, and the interaction force increases with the spacing between tunnels.展开更多
基金Project(2014M560652)supported by China Postdoctoral Science FoundationProjects(2011CB013802,2013CB036004)supported by the National Basic Research Program of China
文摘By combining the results of laboratory model tests with relevant flow rules, the failure mode of shallow unsymmetrical loading tunnels and the corresponding velocity field were established. According to the principle of virtual power, the upper bound solution for surrounding rock pressure of shallow unsymmetrical loading tunnel was derived and verified by an example. The results indicate that the calculated results of the derived upper bound method for surrounding rock pressure of shallow unsymmetrical loading tunnels are relatively close to those of the existing "code method" and test results, which means that the proposed method is feasible. The current code method underestimates the unsymmetrical loading feature of surrounding rock pressure of shallow unsymmetrical loading tunnels, so it is unsafe; when the burial depth is less or greater than two times of the tunnel span and the unsymmetrical loading angle is less than 45°, the upper bound method or the average value of the results calculated by the upper bound method and code method respectively, is comparatively reasonable. When the burial depth is greater than two times of the tunnel span and the unsymmetrical loading angle is greater than 45°, the code method is more suitable.
基金Project(2011CB01380) supported by the National Basic Research Program of ChinaProject(51178468) supported by the National Natural Science Foundation of ChinaProject(2011G013-B) supported by Science and Technology Development of Railways Department in China
文摘With the increasing traffic demand, the closely built three or more tunnels with large section play a significant role in the tunnel construction. However, the interaction among tunnels has important influences on the security and economy of tunnel engineering, and the calculation of pressure from the surrounding rock during the excavation is one of the problems that need to be solved urgently. Based on the practical engineering of three tunnels, the load model of three tunnels was proposed in consideration of the interaction and excavation sequence between tunnels. In comparison with the load model of single tunnel, the construction mechanical characteristics of the three tunnels were analyzed. The results show that the rock pressure of three tunnels calculated by the current tunnel design code is not reliable, and the interaction force increases with the spacing between tunnels.
