Numerical Simulation And Movement Mechanism Of Collapse In The Yanchang County

The collapses is a physical geology phenomenon refering to the high and precipitous slope rock mass or the soil body, under the effect of dead weight and exogenic force, suddenly separated from the mother rock (earth) body and violently came down from the high place. The avalanche, a kind of common natural phenomenon,may also cauded the geological disaster. Therefore, backing the project which is entitled"the particular investigation of geological hazards in Yanchang County of Shaanxi Province", this thesis has studied the collapse hazards around Yanchang County, including geological background, classified and the distribution , and discussed the collapses'forming condition and the influencing factors and carried on the research of collapses'stability analysis and the movement mechanism, and then obtained linear motion equation of the collapses. The major tasks and achievements are as follows:Firstly, through reorganizing and adding up the field investigation materials, the thesis classified the Yanchang collapses and concluded collapses'growth essential feature and the distribution . There are altogether 71 collapses in Yanchang County generally with small scale, locating at the slope with gradient of 60°and height of 8 metres. Collapses occur mostly in the progress or lag of rainstorm and the continuous rain. The collapses'spatial distribution is restricted by the terrain landform and the forming lithology, so the collapses distribute mostly in the concave bank of the Yan River, the both sides of paths and loess girders, the remnant of steep plateaus and the active intense areas of man-made projects. Its time distribution mainly occurs in the months or years when the rainfall is quite centralized and the time when man-made projects'activities are quite intense.Secondly, through investigating the materials, the collapses'forming conditions and the influencing factors in Yanchang County were analyzed and summarized. There are many factors on collapses'forming, divided into the static factors and the dynamic factors.The static factors include: Terrain and physiognomy, lithology of stratum, structure of slopes, geologic structure, types of ground water and so on. The dynamic factor includes: Human activity, rainfall, rivers'erosion, earthquake, weathering and so on. And the static factor is collapses'forming condition, while the dynamic factor is collapses'initiation factor. Thirdly, applicating the stability analyses methods of collapses and the chek projection, the stability to the collapses of typical rock was appraised in Yanchang County. The rockfalls are mostly instability. As to the landfalls, the thesis carried on the analysis appling the numerical simulation, and simulated the the stress strain aroused by excavating the dwelling on slopes with the Flac3D, and analyzed the dwellings'stability and position possibly destroyed with the discharged crevasse.Finally, embarking from the kinematics viewpoint, collapses'movement form and path were analyzed, and the kinematics equation of collapses with models of lean and tension fracture crashes were established. Using the separate element, the movement mechanism of typical landlipes in Yanchang County was analyzed, and the linear regress equation on collapses and landslides distance was obtained, which are used to ascertain the minatory bound coming from the collapses.