Upper bound analytical solution for surrounding rock pressure of shallow unsymmetrical loading tunnels
来源期刊：中南大学学报(英文版)2015年第6期
论文作者：LEI Ming-feng PENG Li-min SHI Cheng-hua XIE You-jun TAN Li-xin
文章页码：2339 - 2347
Key words：tunnel; shallow buried tunnel; unsymmetrical loading; ultimate analysis method; upper bound solution
Abstract: 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.
LEI Ming-feng(雷明锋)1, 2, PENG Li-min(彭立敏)1, SHI Cheng-hua(施成华)1, XIE You-jun(谢友均)1, TAN Li-xin(谭立新)2
(1. School of Civil Engineering, Central South University, Changsha 410075, China;
2. China Construction Fifth Engineering Division Corp., Ltd., Changsha 410004, China)
Abstract: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.
Key words:tunnel; shallow buried tunnel; unsymmetrical loading; ultimate analysis method; upper bound solution
