Rock Mass Quality Classification Appraising And Engineering Effect Analysis Of Toppling Deformation Rock Mass At Miaowei Hydropower Station Dam Abutmet In Lancang River

The dam site of Miaowei Hydropower Station in Lancang River is located inthe erect close type complex fold of the east of Lancang River fold system. Topplingdeformation of the dam abutmet that made of phyllitic sericite slate andmetamorphic gritstone was comparatively strong, and in a big way formed thescale to toppling deformation rock mass.Domestic and international to the choices of the damsite, generally keep awayfrom toppling deformation rock mass.. So, there is relatively less project experienceof building the dam in toppling deformation rock mass., and so there no experiencethat can draw lessons from to rock mass quality classification of topplingdeformation rock mass. So, it is significance of theory and project application that tofound a system of rock mass quality classification that suit to toppling deformationrock mass.The result of classification based on existing classification system of rock massquality classification is very difference of result of live. It is unsuitable to classify toquality of toppling deformation rock mass. Direct against the existing problem, weare in fully considering the special rock mass structure of dam site and out of thecharacteristic of deformation and crack, based on existing systems of classification,through a large amount of fussy surveying, statistical analysis and checking live,adjusting repeatedly the weights and value of five basic indexes and three revisingfactor, make it can describe the basic quality characteristic which topplingdeformation rock mass objectively. In view of the above, we bring forward rockmass quality classification TRM (Toppling Rock Mass) classification system beingsuitable for toppling deformation rock mass, and classify the rock mass of the damabutmet. The paper has done a general estimate of the dam abutmet topplingdeformation rock mass based on the rock mass classification result and tgeological engineering conditions of the dam sitet.The result of study shows, the rock quality of dam abutmet is closely relatedwith complicated rock mass structure and development characteristic of rock masstoppling deformation. The development characteristic of rock mass topplingdeformation of dam abutmet restrict the choice of the axis of the dam and dam type.Through analysing synthetically, project suitable foring of section plane ofⅣ—Ⅳ'isbetter thanⅠ—Ⅰ', and the project of clayey core type rock-fill dam is better thanconcrete face rock-fill dam.