A Study On The Suitability Of Building The High Rockfill Dam In The Underside Dam Site Of The Changheba Hydroelectric Station In Daduhe River

Changheba Hydroelectric Power Station, located at Kangding county of Ganzi autonomous prefecture in Sichuan province, is important water-power engineering.The engineering geology of dam site area is sophisticated. As a whole, the rock slope of the dam abutment is stable, but the deep overburden layer of the dam site's deep is greater than 80m. Its structure is lack of homogeneity and it has multiple-course constructions. Its hydraulic permeability is high and it has sand seam. All the unfavorable factors can course a lot of engineering geology problems, including the liquefaction of sand, seepage flow and differential settlement. By using the standard penetration judgment method and the shear stress judgment method to judge the feasibility of the liquefaction of sand in the overlying stratum of the Changheba, we prove that above the VIII earthquake intensity the sand will be liquefacient and we use the fuzzy probability method to predict the degree of sand liquefaction. By using the numerical modeling we find that the superincumbent bed has the problem of uneven settlement after loading. After the numerical modeling of the superjacent stratum's seep scene, we find that if we did not taking precautionary measures, plentiful water will go though the layer. If we take effective measure the leakage will reduce after the impoundment. We also find that because of the difference of the coefficient of permeability there will be degradation if we do not take seepage control measure. The main form of seepage failure is piping.The study approach emphasizes on qualitative analysis and quantitative analysis together, traditional evaluating means and computing technology together.