Engineering Geology Research on Bounderary Condition of Dam Abutment Resisting Force Body of Dagangshan Hydroelectric Power Station on Dadu River
|School||Chengdu University of Technology|
|Keywords||Dagangshan hydroelectric power station Rocks Mass structure dam abutment resisting force body anti-sliding stability boundary condition connecting rate|
Dagangshan hydroelectric power station is a large-scale hydroelectric power station of principal Dadu River developed recently. Its dam height is about 210m,reservoir storage is about 7.42 × 108 m3 equipped capacitor is 240MW.Arch dam is first choice of dam type at present stage of exploration. The first thing must be done in design proposal of arch dam is evaluation of abutment stability. The main rock character in dam area is Huangcaoshan granite of Proterozoic Era advanced stage that undergo tectonic and reform process long time. Tectonic and reform process result in complex Rocks Mass structure and bounderary conditions of dam abutment. It represents mainly two aspects: The first, the side glide planes of right is clear but the side glide planes of left dam abutment may be composited by random vein and several faults and dikes which is parallel to bang slope. It may be composited by random vein completely. The second, The dam abutment resisting force body’s basal glide planes mainly is constituted by the low-angle veins. These low-angle veins mostly extremely gentle also most undulation. The space position of development is not easy to determine. In order to determine its producing shape, we take average by the multi- spots survey.Through the investigation, on the base of researching dam area rocks mass structure carefully, we have carried on the spatial connection of the steep dipping angle dike and the fault on the dam abutment and at terrene, analyzed side glide planes constitutions as well as the possible combination form. On the base of researching the low-angle veins in exploration tunnels, we has carried on the entire-mark-length investigation, and has calculated in axis of exploration tunnel direction connecting rate with the projection method. Using the Mohr-Coulomb theory of strength and the Barton formula, considered the fluctuating angle influence, we have studied the comprehensive shearing strength value of the low-angle veins on shear direction, and has made the comparison with comprehensive shearing strength value conversed by the low-angle veins connecting rate.On the base of verifying the dam abutment resisting force body boundary condition, using rigid limit equilibrium vector method, Dagangshan hydroelectric power station dam abutment anti-sliding stability analyzing program is compiled. Then, by using above program, the anti-sliding stability of dam shoulders in different modes and different load patterns are calculated in respectively, and their stability is evaluated. The analysis results indicate that the anti-sliding stability of Dagangshan dam abutment can meet the need of arch dam design.