The Risk And Scheme Analyses Of Fast Implementing In The Project Of The Left Export Hole At LongTan Hydropower Station

The LongTan hydropower station locates on the red water river in Tian'e county of GuangXi province. The station's machinery which is the second biggest hydropower station being inferior to the SanXia hydropower station has the power of 6300MKW. Then it is the key project of the national's scheme of"Transferring the electric power from west to east". The project has two exporting holes fixed on the left and right. The cut of the excavation width is 17.9 to 24.883 meter and the height of it is 22.75 to 26.5 meter. After lining, the fracture for drainage has the size of 16 by 21 meters. It's scale has the special character compared to the Er'Tan hydropower station which has the size of 16×19 meters. The construction period is affected of the postponed starting. So we should take proper steps to achieve the original aim.The paper sums up the technology of fast construction, and then analyzes the key technology of LongTan project by using the method of risk analysis and space analysis. After that, the conclusions are showed as follows:(1) It is the key point that we should complete the concrete ling in the body of the cave before the flood period comes in 2003. The export hole should have the ability to supply with the condition of passing water, and it is the cardinal point to make sure the closure of the project.(2) By utilizing the method of risk analysis and space analysis, we apply the theory of New Aurelianensis method. Then the preprinting blasting is introduced to the excavation of LongTan project. It is convenient to locate the construction and improve the efficiency. The construction period can be diminished by three months when the method is used compared to the conventional methods.(3) Through the contrast between the risk analysis, space analysis and progress analysis we draw the conclusion that the scheme of the concrete construction should choose the arrangement which contains two steel diaphragm cars and the sequential of the ling construction should be backplane, side room and then the crest. The scheme can save about one month compared to the scheme of backplane and side crest. (4) The time saved by two methods measure up to four months, so it meets the demand of construction period's regulation and achieves the goal of fast implementing.