Study On The Characteristics Of The Carst Developing At The Dam Of Yangqu Reservoir On The Yellow River And Its Influence On The Project

The draft of the huanghe River-yangqu Hydropower Station is a Power Station that mainly to the large-scale hydropower project, Its engineering design: the dam is CFRD , The maximum height is 159 m, the General storage capacity of reservoir is 2,123,000,000 m3, the Installed capacity is 1200MW.it located in the northern part of Qinghai-Tibet Plateau, Belongs to the northwest drought and few rain area, Exposed strata are mainly giant thick layered limestone of Lower Permian System, Space developing to have karst such as dissolution pore, Corrosion caves and so on,it will give negative influence when use the foundation rock of the dam, And after water storage , it will give negative influence to the water storage efficiency of power station . So study the karst development projects and its impact assessment of the dam site area have great significance.The paper take solid geological and the hydrology geology scene investigation and study as a foundation, summarized 5 kind of karst growth phenomenon of the dam area, then in turn has its classification; At the same time using electron spin resonance (ESR) study on the dam area of karst development, analysis the results of the drilling water pressure test to investigate the rock permeability of the dam area, using three-dimensional numerical analysis the groundwater seepage characteristics of the dam area. The Research results mainly display in the following areas:(1) analysied and researched the topography and geomorphology, formation lithology , geological structure , Regional Tectonic Stability and hydrogeology condition of the dam site area,and has carried on the appraisal to the location geological condition.(2) based on the analysis of the dam site area karst developmental morphology and distribution characteristic,studied the Karst formation mechanism and the distribution, divided the dam site areas karst into five types, and divided the different corrosion space into I, II ,III,IV Four ranks. and a different solution into the space I, II, III, IV four grades.(3) Through the analysis of the weathered rock-mass , the characteristic of unload lotus rock-mass and the water pressure in the borehole stuff. The characteristics of the permeability at horizontal and vertical directions in the dam site can be summed up ,so that the basis for estimates can be provided from this.(4) On the basis of above-mentioned analysis and research, this article make use of three-dimensional numerical analysis method, in accordance with the water before and after water storage + impermeable curtain on the status of the three areas of the dam site seepage were simulated, calculated water After the leak of a curtain circumstances 414.3 m~3 / d, a curtain circumstances 37.07 m~3 / d.(5) Through the dam area of karst features, and rock permeability of the different conditions of the dam area seepage field simulation of the outcome, that the sheep song Hydropower Station Dam Area karst less, little effect on the project.