Study On Controlling Technique For Surrounding Rock Stability Of Three-dimensional Cross-section Of Excavation Transfer Station

With the rapid development of national economy and gradual increasing of the urban population, a large number of urban tunnels need to be built in order to alleviate the traffic pressure. Therefore, it is very important to study large-section shallow tunnel.First, Research on the surrounding rock stability of in the 3rd line Hongqihegou station Tunnel of Chongqing Subway is processed, and then the interaction theory of the B and D sections excavation of the alternate tunnels are discussed. By making simulation and analysis to several construction methods for large span and shallow-buried tunnel through MIDAS/GTS software, optimizes the most appropriate construction method from the solid subsidence, the deformation of the lining, the displacement of the vault as well as the distribution of plastic zones, etc.; the comparative analysis shows that the numerical simulation is consistent with the monitoring.The contents and the results of the study are as follows:First, research on the overlying surrounding rock stability of the large section and super shallow buried tunnel is processed. The supporting parameters are formulated by using the characteristic curves, and the stabled depth of the overlying surrounding rock is calculated.Second, the interaction theory of the cross-section tunnel is discussed. By using the numerical simulation, we calculate the single hole influenced range of the third lining tunnel and advanced influence distance of the sixth lining tunnel in order to monitor the construction.Third, the excavation scheme of the cross section is optimized. By using the numerical simulation, we analyze the interaction on the third lining when the sixth is being excavated. Then we elaborate the reforcement measures when the construction is on progress combing the actual factors.At the last, we discuss the main blasting technology in use for now and the advantages and disadvantages of each kind of the blasting technology. Then we discuss the real blasting scheme and gain excellent effect.