Dam Shoulders Anti-sliding Stability Investigation For Baihetan Hydropower Station On Jinsha River

The arch dam shoulders anti-slides stable and the distortion stable question initiates the arch dam safety incident's primary cause, is also one of dam area key project geology questions. Baihetan the proposed station is the double-curvature arch dam on Jinsha river , and it is another 10 million kilowatts of hydropower station after the Three Gorges of China's, Xiluodu after the survey and design work carried out. Arch dam high 279m, the arch dam when withstands each kind of basic load function, the upstream arches the end most Dollar stress to surpass 1.0MPa, the downstream arches end biggest compressed stress near 10.0MPa, the overall thrust reaches as high as 14,000,000 t, has the enough bearing capacity and the distortion stability as the support arch dam structure's dam abutment rock mass request. Therefore, verifies the dam abutment resisting force body's boundary condition is in detail the dam abutment anti-slippery stability analyses foundation and the premise.The dam area is the Hingham canyon landform, north high south Low, inclines to the east side, valley slope left bank relatively slow, the right bank is high and precipitous, the valley landform shape overall assumes not symmetrically"V"the font. Plans to construct the arch dam section of river is set of Permian is the Mt. Emei basalt stratum, the stratum overall is gentle, has not seen the regional fault, the engineering geology condition is good, is a fine arch dam section of river. The dam area rock mass structure's main body is in the basalt precipitous flow layer level, the level the decantation angle structure moving out of place belt, the small scale fault and the steep dipping angle structure crevasse.The level moving out of place has certain thickness, the penetration to be good, extends the penetration entire dam area, mostly along angle gravel lava and aphanites basalt contact face growth. In the level moves out of place the belt to assume the decantation corniform, in crag flow layer universal growth, especially middle third crag flow layer (P2β32-2, P2β33) in the columnar structure basalt layer, moves out of place belt's growth degree to be higher than other rock layers obviously. In the level moves out of place the belt to extend generally short, has quite the extending length individually.The dam area fault has mainly grown NW, NNW, NE and near NS to four groups of faults, by N60°W to most grows. The fault plane extending length is smaller than 1km much, only has F3 and the F17 control fault appearing length in 1~3km. In the fault zone take grows many kinds of brittle tectonite as the characteristic, as if talking to you face to face the physics and chemistry tectonite, the fault breccia, the fault clay as well as the multiple tectonite and so on, have demonstrated the fault many phase of activity characteristics.The Matrix fracture in left and the right bank dam abutment grows stochastically, the growth superiority position different do not change along with the shore with the elevation, studies in the area except the growth steep dipping superiority crevasse, but also has NE to the crevasse, relative NW to the superiority crevasse, NE extends to the crevasse space in is shorter.This article in the dam abutment rock mass structural property research's foundation, through to the resisting force body spot different scale's level, the level moves out of place the belt and the important fault open country ad hoc survey and the indoor material analysis, the extraction dam abutment resisting force body bottom sliding face and the side crack boundary. The consideration sliding face and the side fracture is different in the different spot's character, uses the partition, the district method to carry on the value separately to the character different spot parameter; At the same time, the union project spot constitutes the dam abutment resisting force body side crack boundary substrate crevasse to the possibility to carry on the connection rate analysis and the synthesis shearing strength parameter value. Finally, discusses the resisting force body boundary possible combination form emphatically, the use rigid body limiting equilibrium analytic method to carry on the appraisal to the white crane beach dam abutment resisting force body's in different load situation stability.The research indicated that the control dam abutment anti-slides the stable macroscopic boundary is as a whole quite clear, the bottom sliding face by in the level, the level moves out of place the belt constitution, leans the fracture is mainly by some short, sparse, the distributed more stochastic substrate crevasse and the part big fault is composed. The dam abutment combination's block body scale mainly leans the crack boundary control, leans the fracture occurrence and locates the project spot control resisting force body's weight and the anti- slippery area. The result indicated: Baihetan abutment body resisting force body's stable overall achieves the arch dam design requirements. Anti-slides the stable weak spot regarding the dam abutment may use the reasonable mechanical control measure to carry on the government.