| Reservoir leakage has always been the top priority in the design and operation of water conservancy projects.In the construction of pumped-storage power stations,various measures have been taken for leakage in the reservoir basin.For seawater pumped-storage power stations,the study of seawater leakage in the upper reservoir is more critical.Firstly,water leakage means energy loss;secondly,leakage will seriously affect the safety of surrounding building foundations and bank slopes;thirdly,seawater leakage will cause serious damage to the ecological environment around the power station.Therefore,seawater pumped-storage power plants have very high requirements on the anti-seepage performance of the reservoir basin.At the same time,compared to fresh water,sea water is more corrosive,and its negative impact on anti-seepage projects and materials is more serious than fresh water.In order to study the applicability of the anti-seepage scheme of the reservoir basin of the freshwater pumped-storage power station to the seawater pumped-storage power station,this paper combines the seawater pumped-storage power station in Okinawa,Japan,through VISUAL MODFLOW and GEOSTUDIO software simulation,and compares the stability of the upper reservoir under different anti-seepage scheme and groundwater solute transport analysis,summarize and analyze its laws.In addition,a system of anti-seepage schemes for reservoir basins of seawater pumped storage power stations has been established,and the anti-seepage form of reservoir basins of seawater pumped storage power plants has been systematically studied.The main conclusions are as follows:(1)Using the finite difference method,based on the MODFLOW-2000 water flow model and the MT3DS solute transport model,the law of the upper reservoir basin’s sea ionic compound(TDS)transport field under the action of the initial basin water system of the Okinawa Pumped Storage Power Station is studied.The results show that the longer the time in the original basin water system,the greater the ion diffusion range,and the greater the impact on the vegetation surrounding the reservoir,and the magnitude of the ion influence range is small in the vertical direction,and the solute transport field mostly diffuses along the surface.(2)Through the SEEP/W-SLOPE/W-CTRAN/W coupling of GEOSTUDIO,the chloride ion concentration(Cl-)and the total amount of sea ionic compounds(TDS)are selected as characteristic ions.This is to predict the impact of different factors on the groundwater system.The results show that the reservoir basin anti-seepage scheme can effectively reduce leakage,lower the infiltration line,and reduce the influence range of seawater ion migration concentration.When the anti-seepage scheme is adopted,the ion concentration influence range is reduced by 90%and the safety factor is increased by 86%.At the same location and at the same time,the greater the seawater concentration,the higher the corresponding ion concentration.The increase in seawater concentration promotes the ion migration speed.The existence of the drainage structure significantly reduces the ion transport field.In addition,weather factors such as strong typhoons are detrimental to stability,aggravate the migration rate of leakage ion solutes in the reservoir basin,and expand the scope of the migration environment.(3)By constructing a reservoir basin anti-seepage scheme system consisting of 5 second-level and 14 third-level indicators,the applicability of different anti-seepage schemes to seawater pumped storage power plants is evaluated based on the fuzzy comprehensive evaluation method.The results show that the final comprehensive evaluation index values of the geomembrane series(PVC,HDPVC,HDPE)are not much different,and the high-density(HD)series is superior to the conventional series.The reinforced concrete anti-seepage scheme has the lowest score(75.643)and the EPDM has the highest score(85.519),which verifies the superiority of the anti-seepage scheme adopted by Japan. |
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