The Key Technologies In The Excavation Construction Of Huge Underground Powerhouse

As the development of national economic, the hydroelectric power engineering, railroad, highway and national defense construction engineering have made a great progress in china, and the application of underground project becomes more and more. In the recent years, theory research, design, construction, monitoring etc. in underground project have got a great development, including pumped-storage hydroelectric power engineering project. During the development of the West Regions and in the construction of pumped-storage hydroelectric power engineering, there will be more and more huge underground powerhouse.The huge underground powerhouse has many characteristics, such as the large span, the high side wall, need to be excavated by several layers, interlaced with many other galleries or tunnels in close distance, and vertically and horizontally intersections on the side wall and roof. There are some key technologies to be researched and get solutions during the design and excavation construction of huge underground powerhouse.This dissertation is going to study the application and the optimization design of pre-splitting blasting in the huge underground powerhouse under the condition of unlimited resistance line through practical test, study the rule of propagation of vibration wave in the earth by blasting and the rule of vibration amplitude reduction by one or two pre-splitting blasting cracks through vibration test technologies and regression analysis. According to these results, make technical measures to control blasting vibration in the excavation construction of underground powerhouse.By the excavation and blasting, the stress redistributed around the underground powerhouse and formed a relaxation-zone. The relaxation-zone can be effectively controled by means of optimized technical measures. It will be very important to take a thickness test of relaxation-zone in proper time in order to evaluate the stability of rock wall and the effectiveness of the support lining, and to advise the design and construction technical measures in the next stage. This dissertation is to study the technical measures to control the relaxation-zone, which make a effective control in the construction of underground powerhouse in ToBa pumped-storage hydroelectric power engineering.Study the monitor technique application in the design and construction of underground powerhouse, the method of forecast the cave deformation . Make use of the actual monitor results of rock deformation , evaluate and analyze the total safety and stabilities of rock wall in the excavation process and evaluate the effectiveness of the support lining.The rock around the underground powerhouse has the characteristic of tension break. Through studying the characteristics of the earth stress distribution , the hard rock break , and the rock stability and safety judgment standard, This dissertation summarizes the tension break judgment standard that influence the rock safety and stability, analyse and evaluate the partial safety and stability of rock in the excavation. The application of this standard in the engineering design and construction, the purpose of rock safety and stability will be got.The results of this dissertation were applied in ToBa pumped-storage hydroelectric power engineering successfully, and the popularization to Hunan heimifeng pumped-storage hydroelectric power engineering is also made successfully. So it has good foreground of application in engineering.