Study On The Construction Characteristic Of Underground Carvens Group For Goupitan Hydropower Station

Researching on the construction characteristic of the caverns group for Goupitan Hydropower Station being built in Guizhou now, the study follows the construction of the item. The construction processes of large-scale underground caverns group under the influence of complex karst system and super large section tunnel construction in soft rock having argillation and rheology are two challenging technology problem in the study. Base on the two problems, the paper systemly discuss construction characteristic, emphases and difficulty of the item. The paper carry out research on seven aspects: complex karst system disposal technique, underground station construction channels programming, construction chief procedure programming, rock bench excavation construction technics of main workshop rock anchor beam, the key construction technique of excavation and shoring in three main holes and special part, underground station super large section soft rock tunnel construction technique and safety monitoring system production analysis of underground caverns group.Goupitan Hydropower Station is built on the karst develop area. A vast karst system, which is complexly distributes in the ground space, is developed in the scope of Station. The big karst system ,such as w24,penetrates several large underground tunnels and chambers such as main powerhouse, main transformer chamber and surge chamber. It is very seldom in China because of its very developing karst and hugeness scope. The stabilization problem is outstanding in underground caverns group, so there is too difficulty in construction and no mature experience can be used. Goupitan Hydropower Station trailrace tunnel is a super large section tunnel. The rock around trailrace tunnel are limestrone, claystone and Argillaceous siltstone. Having argillation and rheology characteristic ,together with local strong airslake along layer fault zone in layer, the properties of rock is quite bad. Under the influence of karst and underground water, the wall rock stabilization condition is too bad, which is very exceptional in hydraulic tunnel in china. The construction problem of large-scale underground caverns group being built on karst developing area and super large section tunnel construction problem in badness geology have been solved through the study. And then a feasible and mature construction method can be summarized, which have an importance meaning and can be used to conduct the item construction and give a reference to similarity item.