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Arch dam abutment stability against sliding and deformation stability of the main reasons that triggered the arch dam safety incidents, is also the dam area of ??key engineering geological problems. Jinsha River hydropower station proposed for arch dam, China after the Three Gorges, Xiluodu to carry out the survey and design work and a million-kilowatt hydropower. Of arch dam dam height of 279m, arch dam subjected to various loads, the the upstream arch side maximum tensile stress exceeds 1.0MPa, the downstream arch side maximum compressive stress nearly 10.0MPa, the total thrust of up to 14 million tons, as the structure of the support arch dam abutment rock requirements sufficient bearing capacity and deformation stability. Therefore, the detailed identification of the boundary conditions of the abutment resistance is the basis and premise of the abutment sliding stability analysis. The dam area is Zhongshan canyon landscape, lying north to south, tilted to the east side, the left bank of the valley slope is relatively moderate, steep right bank of the the valley landforms overall was asymmetric \The proposed arch dam reaches for a Permian Emeishan basalt formations, formation generally flat, no regional fault, engineering geological conditions, it is an excellent arch dam reaches. The main body of the rock mass structure is basalt rock flow layers, layer the gentle inclination construct fault zone, small and medium-scale faults and steep dips tectonic fissures. Dislocation with a certain thickness of the interlayer, through good, extending throughout the dam area, mostly along the contact surface lava aphanitic basalt breccia development. Layer within the fault zone Duocheng slow inclination like widely developed in the rock stratosphere, especially the third rock flow layers Central (P2β32-2, P2β33), columnar jointed basalt layer, the dislocation with the degree of development is significantly higher than other rock. Layers within the fault zone is generally to extend shorter, individual considerable extension length. The Dam Area tomography mainly developed in the NW of NNW, NE and near NS faults to the four groups, N60 ° W to the most developed. Fault plane extends the length of less than 1km, the length only F3 and F17-controlling faults outcrop 1 ~~ 3km. Fault zone within the development of a variety of brittle tectonic rock characteristics, such as foliated tectonite fault breccia, fault gouge and duplex structure rocks, shows the characteristics of the fault multi-phase activities. The matrix fracture on the left, the right dam abutment random development, the developmental advantages orientation do with the shore and the different elevation changes and the study area in addition to the advantages of steeply dipping fissure development, there is also a NE-trending fissures, to the advantage of relatively NW fissures, NE to fissures extend relatively short space. The field special investigation on the basis of the the abutment rock structure characteristics of the different body parts through against the force scale layer, layer dislocation with and important faults and indoor data analysis, extracted abutment resistance body bottom slip surface and The sylvian boundary. Consider the bottom sliding surface and lateral fissure surfaces in different parts of the traits, the use of sub-partition method traits in different parts of the parameter values; engineering parts of the matrix may constitute abutment the resistance side split boundary The fissures conducted the connectivity rate analysis and synthesis shear strength parameters. Finally, the possible combination of the focus on the resistance of the boundary limit equilibrium analysis to evaluate the stability Baihetan abutment resistance body in different load cases. Studies have shown that stable macro boundary is relatively clear, control abutment skid bottom slip surface layer, layer with dislocation sylvian surface mainly by short, sparse, more random distribution matrix fissures and part of the larger faults. Abutment combination of block size is mainly affected by the sylvian border control, the sylvian surface occurrence in which the project site to control the resistance of body weight and slip resistance area. The results show that: the arch dam design requirements to achieve the overall stability of the abutment resistance body Baihetan. For reasonable engineering measures abutment sliding stability weak parts, can be used to govern.
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