The Toppling Deformation Rock Characteristics And Reinforcement Measures Of Research In The Front Of The Dam Of Miaowei Hydropower Station

Miaowei hydropower station is located in Langcang River, Jiuzhou Town, Yunlong County, Yunnan Province. The crest heights of gravelly soil core wall rock-fill dam is 1414.80 m. The maximum dam height is 131.30 m, and the reservoir normal level is 1408.0 m, the corresponding capacity is 660 million m3, with a total installed capacity of 1400 MW. Right before the dam slope is a typical slope of the layered rock slope, The deformation of slope rock mass dumping is very strong, the slope stability is poor, a serious threat to construction safety and The safe operation of the hydropower station. Regarding the side slope in the front of right dam of Miaowei hydropower station as the research object, based on the investigation and study of dump slope deformation characteristics, through the geological analysis and numerical simulation, in-depth analysis and research the dumping right before the dam slope deformation characteristics and reinforcement measures. The main research results as follows:(1)According to preliminary dam site area geological survey data, combined with the practical geological situation of slope in the front of the dam for supplementary investigation and review on the spot, Find out the development characteristic on the surface of the slope structure. Summing up and sorting out geological data, according to the classification system of slope rock mass structural plane in the front of the dam, the front dam slope structural plane is divided into Ⅱ class fracture structure plane, Ⅲ 1 class flat outside slope surface fault structure, Ⅲ 2 class layer in faulted belt, Ⅲ 3 class General fault structural plane, Ⅳ class fissure structure surface and Ⅴ class matrix cracks, and all kinds of engineering geological characteristics of the structural surface are analyzed.(2)Summing up and sorting out the slope surface structure investigation data, analyzing the advantage of slope structure surface(rock formation, joint J1, joints J2), the weak structural plane(Ⅱ、Ⅲ1、Ⅲ2、Ⅲ3 structure surface) and the rigid structure(Ⅳ、Ⅴ structure surface) development of characteristics, and combination of structural plane are analyzed based on the combination of the structural plane on the slope, the results show that the mutual combination can form all kinds of structure surface ladder sliding surface, and gradually upward developed, it is not conducive to the slope stability, especially for play a broken rock mass slope stability is very bad.(3)The front of the dam Produced obvious dump slope deformation phenomena, according to the tunnel expose survey found: dump deformation depth is different in different parts of slope development, strong class A dumping rupture zone development in depth of about 0 ~ 25 m, B1 class strong dumping are cutting layer shear tension fracture zone in the upper depth of about 0 ~ 49 m, B2 class under strong dump deformation of tensile fracture zones within the period of layer depth of the development about 19 ~ 83 m, C weak dumping transition deformation zone development depth of about 28 ~ 182.5 m.(4)By survey of the surface deformation of rock mass dumping phenomenon and adit fine description within the rock mass structure, found the dumping of slope rock mass deformation characteristics mainly for: Layer shear rupture; Tensile rupture inside layer; Cutting layer shear failure; Break- tensile fracture rupture; Slope surface slope, and the fault shear creep; Slope surface slope fault deformation of column. According to the tunnel at the same time logging data and combining the dump deformation degree grading system, established the dumping of the deformation of rock mass slope geological model in the front of the dam.(5)Based on the geologic model, through geological qualitative and two-dimensional discrete element evolution research, it analyzed slope deformation and failure mode. Discrete element calculation result shows: on storage conditions, slope under the action of gravity and water along the slope and hill slope surface slope fault structural plane slip, cracking deformation, with the development of deformation, gradually deepened to the inner slope deformation range, eventually formed in strong dumping area(B1) bottom in the upper parts of the trapezium sliding surface, maximum deformation depth 36 m, Potential instability of slope area is larger, the corresponding reinforcement measures should be taken to ensure the slope stability.(6)According to the dump slope deformation characteristics in the front of the dam and the failure modes of the special, it put forward five strengthening plans combined with three main strengthening measures, they are: slag pressure slope reinforcement, anchor supporting system and slope drainage. And through the state of a two-dimensional discrete element software to analyze the characteristics of deformation of the slope after reinforcement, the results indicate: Slag pressure slope reinforcement is the most ideal reinforcement measures slope surface slope.(7)The limit equilibrium method is adopted for reinforcing plan four and five permanent, temporary and accidental condition stability calculation, the result shows: slag pressure slope reinforcement and anchor supporting system post implementation, the side slope under various operating conditions on the stability of the reinforcing method meet the specification requirements, and has certain safety reserves.