Jinping Hydropower Deep Tunnel Rock Classification

Tunnel engineering and underground engineering will be highly develop in the 21th century, especially the deep-lying long tunnel. The question of geological disaster will be the biggest barrier to deep-lying long tunnel exploration survey and construction in the future, especially high crustal stress and high external waterpressure question. A surrounding rock mass classification that is suitable for high crustal stress and high external waterpressure have great significance to control engineering investment, optimization design parameter and eliminates the latent hazard.The four diversion tunnels of Jinping Cascade 2 Hydropower Station is 16.625 km long averagely and 2525m deep in maximal bury-depth. In the construction region the maximum of principal crustal stress reached 54Mpa. The region belong to high crustal stress area. In the preceding excavation of 5km long exploratory tunnel, several bigger flows had taken place. The maximal water pressure is 10.22MPa. There are few great depth, high crustal stress and high external waterpressure tunnels engineering and few researches on this up to present. If uses the existing commonly used classified method to carry on the surrounding rock mass classification to obtain the very good classified result is not realistic.Therefore must conduct the surrounding rock mass classification research, produce a surrounding rock mass classification method that suits high crustal stress and high external waterpressure tunnels of Jinping Cascade 2 Hydropower Station.The derivation tunnel has not excavated. long exploratory tunnel have the similar engineering geology characteristic with the derivation tunnel, and the material is rich, therefore the present stage long exploratory tunnel is the main object of study on the surrounding rock mass classification of deep-lying tunnel in Jinping Cascade 2 Hydropower Station. This article first utilizes the commonly used classified method to long exploratory tunnel to carry on the surrounding rock mass classification, then carries on correlation, uniformity, the applicability analysis to the classified result, find out the superior and shortcoming of each classified method, in this foundation...