Research Into The Hole Technology In Xi-shi Slope Tunnel

The traditional method of tunnel entrance in order to save the engineering investment, often compressed tunnel length, on the mouth of the cave for big dig and big brush, so that the shrinkage is deep in the mountains, open cut excavation is very big, slope and front slope is very high, the construction often prone to landslides, operation often after the rolling stones fall, endanger the traffic. In order to realize the green environmental protection into the hole, the "front entrance method" in the Xi-Shi Po Mountain Highway tunnel shallow buried condition into the application of tunnel construction. Using FLAG3D software for the mechanical behavior of tunnel front entrance of the construction process was simulated to analyze the stress field, displacement field distribution of surrounding rock and front-portal section supporting structure, while the construction of portal section site dynamic monitoring, timely understanding of the dynamic deformation of tunnel surrounding rock, guide field construction, to provide practical basis for optimizing the supporting structure parameters. The concrete research content:1) Existing successful experiences are summarized and analyzed for the tunnel entrance hole program under different topographical and geological conditions. Summarized in similar terrain, geological conditions, the tunnel entrance hole technology.2) By understanding the geological conditions, rock levels and topography of the region, using the finite element software FLAC3D of Xi-Shi Po tunnel use of "front entrance method" into the hole construction step numerical simulation analysis, study of the stability of surrounding rock of tunnel, the construction of the security hole and front entrance method superiority. 3) Deformation monitoring is one of the three elements of hole in construction technology, in accordance with the requirements of the tunnel construction of Xi-Shi slope deformation at the tunnel entrance for real-time monitoring. Introduce monitoring of major projects, content, purpose, equipment selection, based on the analysis of monitoring results to verify the front entrance method for the practical feasibility of the mountain tunnel entrance of Shallow buried condition.4) The simulation results and tunnel monitoring comparative analysis of measurement results, mutual authentication, summarized the rule of surrounding rock deformation of tunnel, its stability evaluation, to ensure the safety of field operations, while providing a reference for similar conditions of engineering, guidance and further research role.