Study On Deformation Mechanism Of Layered Slope Deformation In Jinning Phosphorite

Study on deformation instability mechanism of slope is a systematic engineering,which includes analysis of the factors affecting the stability of layered slope, stability analysis of rock in the research area, the numerical analysis method and so on. Research alone in a certain respect cannot have a comprehensive understanding of slide mode of slope. This paper takes research on landslide model of layered slope in Jinning phosphate rock as topic, from the point of view of theoretical,mechanical analysis and numerical simulation, explore the deformation instability mechanism of slope deeply and systematically. The specific contents are as follows:(1)Mechanical properties of layered rock mass are studied,which includes anisotropy of deformation and strength in layered rock mass, mechanical properties of the structure. Based on the theory of mechanical properties of layered rock mass, the paper mainly discussed the influence factors of the stability of layered slope, that is, the stress of rock mass, the dip angle of strata.combination of formation lithology, strength of rock mass, water, shape of slope, vibration, man-made factors and others. At the same time, use FLAC/SLOPE to build model, focus on the internal cause of slope stability to have a single factor analysis of influence,that is dip angle, slope angle, thickness of strata,strength of rock mass, the level of intensity, change of strata occurrence.(2)Based on Jinning open-pit mining conditions, with the scene investigation of deformation characteristics of slope deformation, using the measuring line method to have the measurement of structural plane in rock mass, using Rocscience Dips to divide the preferred structural plane of the sand shale into three groups, are level and two groups of joint surface. Analyse overall geometric features in preferred structure planes statistically,with the help of SPSS to calculate the mean, standard deviation of the processed data and draw the frequency histogram, verify that changes of field occurrences obey the normal distribution. Finally using stereographic projection to evaluate the slope stability, level is preferred structural plane that affects the slope stability.Analyse excavation deformation and failure mechanism of layered slope in mine, and determine the failure mode of slope. Through indoor rock mechanics test of rock mass, evaluate the stability of rock slope, determine the mechanical parameters of rock mass, lay the foundation for follow-up stability analysis of slope excavation.(3)The layered rock slope are modeled by using FLAC3D, analyse the mechanics response characteristics of the rock slope and the mechanism of deformation and failure from the displacement field, stress field, distribution of plastic zone,come to the conclusion that along with the excavation of slope, displacement of the slope edge, turning point and foot of the slope that are next to the face of excavation are maximum. Displacements of high slope in the mining process are gradually increasing, rock slides downwards to make it stand the strong extrusion and expand in the turning point, then the slip surface gradually is through and develops to landslide. This landslide usually have the same characteristics with collapsing and sliding, the evolutional process of the slope deformation and failure proved that the instability mechanism of sliding-bending -shear failure. Due to shear outlet hanging in the central slope, the instability mode shows a high speed slide after sheared at top.(4)Prevention and reinforcement of open-pit slope is a complicated systematic project, on the base of finding out the slope engineering geological conditions, analyse the failure modes of layered slope, and then follow the characteristics of open-pit mining, put forward prevention measures of landslide, that is blocking, discharge, steady, reinforcement and so on, in the local area take bedding clearing, anti-slide pile, anchor, grouting, drainage and other comprehensive measures to ensure slope reinforcement, maintaining the overall stability in the mining period.