| People can't avoid to reform the surface rock of lithosphere in the process of production and construction, among these activities, water resources and hydropower, mining and road construction and other large infrastructure of the rock excavation will be resulted in many high rock slope. In the large-scale hydropower construction, as the size of project growing and geologic constraints, the height of spandrel groove is increasing and the problem of stability is appearing day by day, therefore, to study on the its stability by identification of spandrel groove slope engineering, advancing research ideas and analysis methods, for optimal excavation slope ratio to keep safe on the construction and operation has important meaning for the construction and normal operation of hydropower station.The paper selects the left and right spandrel groove slope of Baihetan Hydropower Station as researching object,in connection with groove for the arch of the engineering geological conditions of slope, fully absorbs the advanced academic thinking of"mechanism of geological processes","quantitative evaluation"and"rock structure control theory"and other, on the basis of the research status and the collection of date, opts qualitative geological analysis and quantitative calculation research ideas. The thesis is mainly through regional geological and environmental condition study, many investigates on the surface area and rock structure, combines statistical analysis of indoor, to summary the development law of spandrel groove surface of different parts of the hierarchy of space, establish rock mass structure model, and then, to calculate and evaluate arched groove slope stability under different conditions, main contents as follows:(1) On the basis of previous research, I has done detail research on the engineering geological conditions of Baihetan Hydropower station dam and spandrel groove slope: include regional geological environment, arch groove slope topography, litho logy, geological structure, hydrogeology and unloading areas weathering etc.(2) Research on the rock arch structure of spandrel groove slope: the paper analyses the structure characteristics of the rock slope about the left, right bank on downstream side. Include the construction of the dam area native structure surface, surface structure and surface reconstruction structure transformation of the structure surface, also faults of different sizes, layer, layer faulted zone, deep cracks and fissures characteristic matrix and its distribution pattern and classification researching, pointed out that the structural characteristics of the rock slope similarities and differences. According to the research on the structure at all levels of surface features and composition, to analyze the left and right bank of the spandrel groove slope and give an assignment to the controlling of the physical and mechanical parameters boundary. To establish a reasonable conceptual model for rock mass structure and then, establish a scientific basis in fact for the deformation mechanism for the follow-up analysis and quantitative calculation.(3) Research on rock mass classification of spandrel groove slope: in order to analyze the whole stability of spandrel groove slope, definite a reasonable excavation slope ratio, study on characteristics of rock mass structure on the basis of rock classification for qualitative and quantitative classification. Classification to be adopted on-side qualitative and quantitative research methods combined classification; opts the CSMR classification method quantitative grading standards by The People's Republic of China Water Conservancy《Water Resources and Hydropower Engineering Slope design specifications (SL386-2007)》. Composite two classification results, obtained comprehensive classification results.(4) The analysis about spandrel groove slope stability of left and right bank: combination the rock slope deformation model, on the basis of natural slope stability, through the arch groove on qualitative analysis, and use the limit equilibrium calculations and theoretical calculation block arch groove on the overall stability and local stability of the slope of the quantitative analysis and evaluation, and probide the basis for the optimal design of slope tatio.The paper obtians the mail results are as follows:(1) The mainly controling structure of spandrel groove surface slope contains: F17,f108,f110,f111,f112,F16,f247,f249 etc. size; C3-1~C6,LS423,LS414,LS3319,RS621 etc. layer and layer faulted zone.(2) The stability of spandrel groove slope in Baihetan Hydropower Station is mostly good: the left bank rock is mostly of gradeⅢ1, about 52.9%, second is gradeⅢ2 andⅡ, respectively 18.3% and 14.5%, gradeⅣrock is about 14.3%, gradeⅤrock is only 1% (only appears in the left bank of the downstream side); right bank rock is gradeⅡand account for about 44.2%, followed byⅢ1 andⅢ2 level, respectively 27.6% and 19.4%,Ⅳgrade rock about 8.8%, the right bank rock is not gradeⅤ. Therefore, the quality of spandrel groove slope rock is mostly good, can be used a higher degree, the slope stability is good, and the right bank of the arch groove slope stability is better than the left bank.(3) The natural slope and the slope of spandrel project groove of left bank is overall in a stable state.Local unstale bolcks are seven and these scales are small, their influence depth are limited, in the natural state and arch groove in the excavation are also in steady state, only in the downstream side of the partial collapse can generate small-scale construction should be clean before handling the crisis.(4) The natural slope and the slope of spandrel project groove of right bank is overall in a stable state. Local unstale bolcks are three and these scales are small, their influence depth are limited, in the natural state and arch groove in the excavation are also in steady state. The global and local slope of the right bank dam are both in a stable state.(5) The optimal design of spandrel groove slope excavation: Spandrel groove slope of left bank: new and slightly lower weathered rock mass: 1:0.2~1:0.25;lightly upper weathered rock mass: 1:0.35~1:0.5;the covering layer: 1:1.1~1:1.2.Spandrel groove slope of right bank: new and slightly lower weathered rock mass: 1:0.20~1:0.25;slightly upper weathered rock mass: 1:0.35~1:0.50; the covering layer: 1:1.10~1:1.20. The left and right spandrel groove slope excavation needs to set a 3m wide service road every 30m; slightly upper weathered rock mass excavation needs to set a 3m wide service road every 30m; the slope ratio excavation options of right bank dam is: slightly lower weathered and new rock mass: 1:0.25 ~ 1:0.35, the lightly upper rock mass: 1:0.40 ~ 1:0.45 ;the covering layer: 1:1.10 ~ 1:1.25, the slope excavation of dam needs to set a 3m wide sevice road every 50m . |
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