| Jinping two-stage Hydropower Station is located in the Yalong River in Liangshan Yi Autonomous Prefecture of Sichuan Province. Jinping two-stage Hydropower Station is a power stations with low sluice, long tunnel, high head and high flow rate. The control project of the station is the four diversion tunnels, which are not only long, but also with large diameter and high depth. As lithology of the area is mainly marble and a small amount of sand slate, which the rock is relatively unitary, so in addition to the traditional drilling and blasting method, it is also uses a very high degree of modernization of tunnel boring machine (TBM). During the construction process, which the traditional classification of the surrounding rock based on drilling and blasting method has the disadvantage of TBM. From this phenomenon, by research and analysis to the difference of surrounding rock in these two different mechanisms of deformation and failure, I expect to find the reason what traditional rock classification of drilling and blasting method is no application to TBM. This study are as follows:1. At the construction site we had collected a lot of field geological survey and analyzeedit. The terrain with tunnel cross is ups and downs and elevation are more than 3000m. The highest peak is 4113m. Along the diversion tunnel through the strata of the Triassic strata is the main lithology marble, and the western end of the small amount of biotite schist, slate and sand. Lithology and geological structure's direction is main NNE. Engineering karst is developed, but the rocks with varying degrees of regional metamorphism, a decline of soluble marble. The diversion tunnel has a great depth of features, so prominent rockburst.2. As the main diversion tunnel through the rock mass of marble, carried out under different loading rates, different construction conditions Jinping marble of acoustic emission testing. Fully reveals the marble test crack initiation, propagation, through the process of stress, strain, AE characteristics. From the test results, we can see deformation of marble is a centralized way of violent destruction in the form, and acoustic emission mainly in the period after the destruction of marble. Compared with the drilling and blasting, blasting the TBM does not produce power, so that the increase in the mechanical properties of marble, marble obviously enhanced the anti-sabotage.3. Scanning electron microscope for the micro scale, effective tool for observing surface. Through the scanning electronic microscope, studies under the different execution conditions the marble plane of fracture in views carefully under the criterion the character of surface: In drills explodes under the law execution conditions, the marble is under the demolition impact the influence, the rock fracture pulls the destruction and cuts the destruction very much to grow; But the TBM broken crag cuts, the pressure to cut the rock primarily, the rock fracture cuts the destruction primarily, the part to open the destruction.4. FLAC3D analyzed by numerical simulation of stress field and the diversion tunnel construction under different secondary excavation size and distribution of stress and deformation characteristics of rock, distribution of plastic zone. Numerical simulation results suggest that estimates based on different parts of the rock cavern stages of deformation, damage type and size. |
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