The Study On Influence On The Safety Of The Dam And Stability Of 1~# Toppling Deformation Rock Near The Dam Reservoir Of The Huangdeng Hydropower Station On Lancang River

1# toppling deformation rock of Huangdeng hydropower station on Lancang river develop at reservoir near the dam located in the upstream side of No. 1 gully belonged to the upper reaches of the right bank on the damsite district.Stability and catastrophic effects of the deformation rock, will directly affect whether hydropower station is set up or not ,a nd that selection and setting of the dam line and dam type program, the smooth progress and normal operation of construction.Studies show that toppling deformation and fracture phenomenon of 1# deformation rock is extremely complex, summarized which mainly include three basic types of deformation what is"toppling-creeping"inside the deformation rock,"toppling- slipping"at the bottom of the deformation rock, "toppling - bending, folding" at the trailing edge and the deep bottom boundary. This unique and complex deformation is mainly controlled by the deformation of"toppling- shearing and slipping"at the bottom of the F217-3 fracture surface.Two-dime FEM analysis show that the stress value is slightly higher than the natural state generally when the deformable body is on unfavorable working conditions of the reservoir water,earthquake or earthquake+reservoir water. A certain stress concentration and stress differentiation occur at the intersection between joints in the foot and breaking zone and intersection area among the breaking zone at the upper of the deformation rock, in particular, the performance in extreme working conditions is more obvious. This situation is more Notable near the profileâ…¦-â…¦/ at downstream side of the deformation rock.Two-dime DEM numerical analysis show that, near the profileâ…£-â…£/ at upstream side, relatively large horizontal shear displacement on Lower slope is controlled by a double slip effect of the underlying transited joint and breaking zone , and thus nearly horizontal shear extrusion occur at the lower rock of the slope, which at the same time cause the upper part generate into further toppling; near the profileâ…¦-â…¦/ at downstream side, the main weak toppling occur at the lower slope, which resulted in increased toppling deformation of the upper rock, and there exists trend that cantilever toppling bending deformation developing into shear creeping- cracking deformation. Further more,limited equilibrium analysis shows that A class strong toppling deformation and fracture rock near the profileâ…£-â…£/ which also is the rupture modeâ‘ , may be unstable failure in the limited condition; the lower deformation rock which also is the rupture modeâ‘¡controlled by fault F217-3 and the steep rift zone near the cave PD215((PD215 cave, 1640m elevation below), may be unstable failure in the conditions such as Reservoir storage, reservoir water level declined sharply and the Earthquake, and the lower deformation rock is potentially unstable.Against that above potential unstable rock, Pan Jiazheng method and Energy method is respectively used on calculating falling velocity of rock lost stability,and then Shui Keyuan Empirical formula method and Pan Jiazheng method is used on forecasting the surge height of unstable rock sliding into reservoir. The calculation results analysis show that the surge generated by the unstable rock would not constitute a serious impact to dam itself, but will have a greater impact to the normal passage of water near the dam and ecological environmental of reservoir banks.The research results of the paper not only provide a reliable scientific basis for the stability evaluation and the choice of supporting treatment programs of 1# deformation, but also provide an important reference for engineering layout of reservoir near the dam,ensure the smooth progress of construction safety and preparation of disaster prevention planning of river basin.