Study On Development Characteristics And Genetic Mechanism Of Low-angle Structure Face At Ma'erdang Hydropower Station

Rock mass is an important groundwork of large complicated trucural engingeering such as high cinstructions, bridge engineering, tunneling engineering, and hydraulicconservancy hinge and so on. There are many discintinuiries with different scale, direction and character the existing of discintinuinuities not only break the integrity but also affect the mechanics property and failure model of rock mass, it is a very important factor in influencing stability of rock mass. Therefore, it is important to research the property of discontinuity.The structural plane, such as fault, layer and fracture, in dam site of Ma'erdang hydropower station located in upper reaches of the Yellow river, was fairly intensive, notably low-angle structure face which was distributed in deep part in dam site and rare in similar geotechnical engineering. Low-angle structure face, potential threat for dam foundation and abutment, was the principal plane having a controlling effect on slope sliding. By affecting the partial and total stability of top and bottom plate and pattern of deformation of surrounding rock, the plane had an adverse effect on underground powerhouse, power tunnels, diversion tunnel, traffic hole and other underground construction, especially in such area with high crustal stress. Therefore, by detailed investigation of engineering geology essential part of research, reasonable classification and study on forming principle which can offer a reference for designing and distribution of the engineering, was done, after surveying the development characteristic, features of spatial distribution, composition and pattern of substance in the plane.Based on the regional geologic environment, engineering geological status, investigation in the field and collecting data, development characteristic and genetic mechanism of low-angle structure face in Ma'erdang hydropower station was studied.The study of angle structure face in Ma'erdang hydropower station was concentrating on following points:(1) geological environment of this region and dam site, (2) spatial distributing pattern of low-angle structure face, (3) the degree of development of low-angle structure face, such as distributing and development pattern of width and intensity, (4) the morphology of configuration of low-angle, (5) developmental scale of low-angle structural-plane, including thickness, material filled in the plane, degree of consolidation, length and connecting rate, (6) classification of low-angle structure face, (7) developing pattern and mechanism of low-angle structure face.