Research On The Curtain Grouting In The Upper Reservoir Of Taishan Pumped-storage Power Station

During the development and utilization of hydropower resources in our country, we have constructed many pumped-storage power stations. As pumped-storage power station always require unique geological condition,the upper reservoir must lie in high place with small reservoir capacity relatively, and the water level varies frequently, all those factors contribute to the vital importance of anti-seepage, which can be solved by vertical curtain grouting because of its advantage of seepage-proofing. This paper is based on the curtain grouting in the left bank of Taishan pumped-storage power station, by means of theoretical analysis、monitoring、 test and numerical simulation after collecting a large mount of relative information, the main research contents and results as follows:(1) By summing up previous research result, collecting and reading relative engineering information, the technical route is put forward. The research area lies in the fourth and fifth part of the curtain on the left bank, where the underground water is bedrock fissure and porosity diving water which without corrosivity. The main rock is stripes mixed rock with big faults in the area, and the joint fissures are developed. And then the main control parameters are analysed after introduction of the curtain goouting mechanism.(2) Then the research is carried out by means of monitoring and test. After seepage monitoring we find that the seepage flow is high, which the maximum is 1587.17cubic meter per day. By water pressure test on three drilled holes, we find that the average permeability rate are 2.42 lugeon、1.29 lugeon、3.34 lugeon respectively, from which we can conclude that the curtain doesn’t meet the requirement any more because of the the average permeability rate are all bigger than the required 1 lugeon.(3) The curtain gouting is studied by numerical simulation then. The formula of calculating the seepage flow by means of finite element method is derived after introduction of the basic concept of seepage. And then, the seepage flow model is established and the curtain grouting under different circumstances is simulated. From the simulating result we can conclude that the designed curtain satisfied with the requirement, while the effect of anti-seepage reduces gradually, the seepage field changes and the seepage flow grows, the maximum seepage flow reachs 30.16 liter per second when the curtain is failed totally.(4) Based on all the research above, the anti-seepage effect of the curtain grouting is analysed. First, the quality of the design and construction of the curtain grtouting is evaluated, and we conclude that curtain grouting met the requirement during the construction of the reservoir. And then, from the monitoring and test results,which the average permeability rate is bigger than the required 1 lugeon, we conclude that the curtain grouting isn’t satisfied with the requirement any more by comparing with the previous data, the permeability coefficient is about 3.53 ×10-5 centimeter per second, and the seepage flow is 18.37 liter per second. So the curtain grouting is still working but not satisfied with the requirement, and then some suggestions are put forward.