Study On Construction Procedure And Excavation Method Of The Large Underground Powerhouse

The scheme of underground powerhouses has been used widely in the hydroelectric project. And with the exploitation of the waterpower materials in the main rivers one after the other, the underground powerhouses and the associated cavities in the hydroelectric engineering are developing towards the large-scale way. Nowadays modern equipment is applied widely in the excavation of underground powerhouses, so it is significant in the practical engineering to study the construction procedure and excavation method of the underground powerhouse. The excavation of the large underground chamber, especially the underground powerhouse, will be studied deep in this paper. And some important standpoints and conclusions are made.Firstly, according to several excavation examples of the domestic underground powerhouses, the construction characteristic and possible problems are analyzed.Secondly, according to many examples of the excavation of tunnels in the hydroelectric engineering, some influence factors of construction methods of large underground chambers are analyzed. Some factors are discussed in detail, such as shape and scale of the cavity, rock stability, equipment, etc. The primary proposal is tabled to choose the excavation method of underground tunnels.Thirdly, the construction procedure and excavation method of the large underground powerhouse are studied. And the typical multi-layered scheme is analyzed considering of the factors that influence the multi-layered excavation of the underground powerhouse. And based on the rock pressure theory, applying the ANSYS software and engineering examples, the excavation procedure of the top heading of the underground powerhouses is studied, and the recommendable project of the top-heading excavation is made.Furthermore, according to the blasting vibration and rock mass damage, such associated construction problems as the excavation method of the bench of the crane beam and the benches under the crane beam are discussed.Finally, after studying the channel designing of several domestic underground powerhouses that are building now, the elementary principle during designing the temporary access tunnels in the underground powerhouse system is described. And the typical access designing method is analyzed.