Rock Mass Structural Features And Its Contral To Dam Shoulders Anti-Sliding Stability In Baihetan Hydroelectric Power Station Dam Site Of Jinshajing

Baihetan hydroelectric power station of Jinsha River is another planned giant project after Three Gorges and Xiluodu Water C onservancy P roject i n C hina. I ts d am height i s 2 87m, equipped capacitor 12000MW and Permian Emei Mountain Basalt is the main strata in dam site. Field investigations show that there are discontinuities such as interlayer shearing belts, instrastratal shearing belts, faults and base crack. The discontinuities control the stability of Rock Mass against high arch dam shoulders Anti-sliding stability which is the main engineering geological problems in Dam Site. In this paper, Rock Mass Structural features have been studied systematically, anti-sliding boundary condition is defined and dam shoulders anti-sliding stability is evaluated based on studying on the Genesis of Rock Masses Discontinuities and geological investigations, data statistics and indoor test.Based on research productions that have been obtained, Basalt Lithofacies features and action of Rock Mass Structural and tectonic stress field are generalized. Field investigations found that epigenetic reworking deformation fracture include 3 types, named normal relief fracture, fracture filled mud and epigenetic reworking of disturbed belts. And epigenetic reworking of Rock Mass structural also includes gradual deformation of the blocks that are made up of different attitudes structural planes besides normal relief. Through field geological investigations, the features of Rock Mass structural planes are generalized, especially development laws of interlayer shearing belts, instrastratal shearing belts, faults and base crack.Based on the studies of Rock Mass structural in dam site, 14 groups basal glide planes are elected from interlayer shearing belts and instrastratal belts. According to Baihetan hydroelectric power station dam shoulders load, side glide planes are fixed on both banks, which is controlled by base cracks on the left bank and by fault F18 and base cracks. And engineering geological characters of side glide planes.Based on clear boundary condition of dam shoulders, with rigid limit equilibrium vector method, Baihetan hydroelectric power station dam shoulders 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 Baihetan dam shoulders can meet the need of arch dam design.