The Research On The Leakage Analysis Of Tiankai Reservoir

Tiankai reservoir started in 1959, was built in 1960.Because the karst leakage problem of the reservoir and main and auxiliary dam foundation, the reservoir has not been successful to retain water. And the dam only has played the role of short-term flood. In order to preserve the original design function of the dam, to make Tiankai reservoir can be successful to retain water, the author is urgent to carry out the analysis, evaluation and calculation of the karst leakage in the reservoir, and the calculation results can guide the later anti-seepage processing scheme. Based on the actual operating conditions of Tiankai reservoir project, the paper analyzes the seepage stability of the main and auxiliary dam of reservoir, analyzes and evaluates the calculation of reservoir leakage, and contrasts the reservoir anti-seepage processing schemes. The main results are as follows:(1)The paper adopts the seismic surface wave exploration method and the natural electric field method to delineate mainly leakage area and concentrated leakage points of the reservoir. It adopts the high density electrical technique to find out the leakage passage and the ancient river. Meanwhile it adopts the connection test to verify the results in the concentrated leakage, the verification results show that the determined leakage passage is accurately.(2)the paper adopts Geological drilling in the delineation location of reservoir leakage point to expose the reservoir rock mass integrity, permeability, spatial occurrence of joint fractures and the filling particles of karst fissure. At the same time, the paper adopts borehole tv and borehole acoustic wave test in the hole to find out the rock strata in the development of fracture, and it uses the method of three point calculate the occurrence to find the cracks and structural belt, determine that the direction of structural cracks and the direction of the leakage channel are same, the directions are all pointing to the reservoir water leakage.(3) in the 21 days time of "7.21" event, the paper uses formula to calculate: leakage quantity of karst reservoir area channel is 0.7908 million m3, leakage quantity of ancient riverl is 0.1763 million m3, leakage quantity of dam foundation seepage is 0.0064 million m3, the total leakage quantity is 0.9735 million m3. The paper uses the observation data to calculate: the total leakage quantity of the whole reservoir is 1.101 million m3, the total leakage quantity of main dam, the auxiliary dam and karst channel is 0.9735 million m3, accounting for about 88.4% of the whole reservoir leakage.(4) By the seepage calculation and leakage mechanism analysis, the paper considers that the most water leakages to downstream by the ancient river of the main dam and the auxiliary dam and karst channel, other small water may leakage to the deeper reservoir area by karst fissure,less water also may leakage to the reservoir downstream by the karst fissure of spillway in the reservoir southeast.(5) By comparing the three schemes of the local horizontal anti-seepage, the whole horizontal anti-seepage and Vertical anti-seepage, the paper considers that the local level costs is the lowest, and its anti-seepage effect is better.The research results of this paper can provide scientific guidance for the future engineering construction of Tiankai reservoir, and the analysis theory and method of karst leakage in this paper can provide reference for the construction of karst reservoirs of other northern region in the future.This paper also accumulate the successful experience of karst investigation, it can also promote the wide application of comprehensive survey technology.