Research On Stability Of Perilous Rock In High Slope Of Pu Er Du

The perilous rock usually develops in the mountain and ravine region, road slopes, steep slopes and cliff, which is the one of the common types of geological disasters. Outbreak of the perilous rock mass collapse often has the sudden, high energy and destructive characteristics; which has caused lots of casualties and-economic losses in-our country every year. This paper analyzes the perilous rock strata of high slope of Pu Er Du Huang Gewan area and engineering geological characteristics on the basis of geological disaster prevention project of Pu Er Du, Yan Jin County, Yun Nan province and field investigation and also established3D geological model of research area according to the measured topographic map, prospecting and drilling data and experimental data. In the mean time, the numerical analysis software (FLAC3D) is used to calculate and analyze the model; It establishes four mechanics models of differential weathering perilous rock though the high slope of topography and engineering geological characteristics, then studies the failure mechanism of it. This paper main research contents are as follows:(1) This paper analyzes the development influence factors of perilous rock high slope of research area such as meteorology and hydrology, topography, formation lithology and geological structure characteristics and so on though field investigation and survey data.(2) This paper analyzes the rock accumulation of main stone slope, rocky outcrops and mudstone weathering cracking characteristics in study area by which combines investigation with drilling data. It measures106joints distribution of the cliff by traverse method and makes the plane distribution map of joint networks and stereographic projection map of joint networks, then though it, analyzes the engineering geological characteristics, formation mechanism and collapse ways of perilous rock high slope.(3) This paper establishes3D geological model of perilous rock high slope of study area according to engineering investigation plane map, geological section and profile map and also calculates the stress field, displacement field and distribution map of plastic zone by the numerical analysis software (FLAC3D). In addition, It establishes two groups of contract models:presence of mudstone cavity model and cliff feet2m deep weathering mudstone model, which analyzes the escarpment rock bulging, dangling, rock cavity structure caused by mudstone weathering cracking concave and foot mudstone rock weathering influence on the stability of the steep cliff.(4) According to the strength subtraction calculation method of the numerical analysis software (FLAC3D), it calculates the safety factor of perilous rock high slope in study area, evaluates the stability of the slope and also analyzes the position of potential glide plan and shear outlet.(5) It derives that the calculation formula of compressive stress of the mudstone back cavity of differential weathering mudstone rock increases with rock cavity depth according to feature of cliff rock and mudstone cavity caused by the sand mudstone weathering differences formation in study area.(6) According to the Pu Er du’s perilous rock slope topography,geomorphology and characteristics of geological structure establish two kinds of four differential weathering perilous rock mechanics model:The first type is the mudstone base fracturing damage type and rotational damage perilous rock whose main control fissure connectivity rate equal to1; The second type is the falling and toppling perilous rock whose main control fissure connectivity rate is less than1. Use of rock strength theory derives sandstone study area’s quadratic parabolic Mohr strength envelope equation; Using the limit equilibrium theory and Mohr strength theory deduce the collapsing damage and judgment expression of four kinds of perilous rock under the gravity, earthquake force and fissure water pressure; basing it reverse derive critical collapse boundary equation of study area perilous rock mass and the relationship among rock cavity depth, thickness, height and the main control fissure depth, which provides intuitive and reliable basis for prediction and the judgment of perilous rock mass stability and collapse.