| After the Ludian earthquake, a large number of secondary geological hazards are induced, including landslides, debris flows, collapses, and shatter mountains and so on. After several rainy seasons, the secondary geological hazards after the effect are gradually emerging. Secondary geological hazards problems in disaster areas emerge in endlessly, many of them have large scale, high degree of threat. And the key part of the slope stability problem which is directly related to the construction of water conservancy project is particularly important. Taking the topic “engineering geological characteristics and stability evaluation of the potential unstable slope of Wang jiapo ” as the basis, the author studied the surface structure of the unstable slope of Wang jiapo, investigated and analyzed of the stratum lithology, material composition and distribution of Wang jiapo, and built the reasonable geologic model. On the basis of the study on the deformation and failure characteristics of the slope, the author summarized the mechanism of the formation of the slope, and put forward tow potential failure modes :(1)Plastic flow and tensile failure;(2)Creep and tensile failure. On this basis, the author determined the boundary and smooth combination which may constitute a slope of different sizes(overall or partial) sliding damage. Through the analysis of the two dimensional limit equilibrium of the strong deformation zone of the slope and the three-dimensional numerical simulation of the whole slope, the author focused on the stability of the slope under the three conditions, which makes a reasonable evaluation of the stability of the slope, and he put forward the corresponding countermeasures and suggestions.The specific research contents and results are as follows:(1) The author has studied the engineering geological environmental conditions of the unstable slope of Wangjiapo in the study area, and has focused on the analysis of the geological structure, especially types, extension, strike and so on of the Ludian Earthquake Fracture Bao gunao~ Xiaohe fault in order to further analyze the deformation and failure characteristics of the slope.(2) The author has studied the structure characteristics of the slope of Wang jiapo, mainly including rock mass structural plane classification, rock mass structure classification and slope formation condition, composition material. According to the slope material lithology and rock mass quality level, the author expatiated the full~strongly weathered layer and Permian Liangshan formation of Wang jiapo deformation destruction border control, and then established a slope geological model.(3) According to the present disclosure of the slope deformation damage, the author divided the slope into four zones, which are the strong deformation zone(zone I), the weak deformation zone(II), the H2 landslide area(III) and the H3 landslide area(IV) by means of deformation and failure. Combining the lithology combination and the structure characteristics of the slope, he analyzed the mechanism and mode of deformation and failure, proposed the potential failure mode and determined a different scale(global or local) boundary and smooth combination of sliding failure.(4) Based on the potential sliding surface, the author used the method of limit equilibrium analysis under the three conditions of natural, heavy rain and earthquake. Calculation results showed that different location of profile of slope stability coefficient vary greatly, which explained that the different parts of the slope were affected differently under the action of strong earthquake or rainstorm. From the current situation, there is a certain size of the potential risk of instability on local area under extreme conditions. Finally we drawed the conclusion: There is a very small possibility of the whole rapid failure of Wang jiapo, but we did not rule out the possibility of local instability and destruction of a certain scale on the front of the slope. in heavy rain, earthquakes and reservoir water and other factors. |
PDF Full Text Request