Research And Analysis On Gangue Dump Formed By Filling Gully And Flating

With the continuous development of China’s coal industry, a large numberof waste dumps are associated. Those waste dumps mainly have two kinds ofaccumulation forms: piled up by flat bottom and cone, formed by filling gullyand flating. The waste dumps which are formed by the two accumulation formsmay cause geological disasters, and thus pose a threat to the local personalsafety and property security. Many experts and scholars at home and abroadhave been some studies on the stability of the waste dump, and have achievedcertain results. Based on the reference of previous results on the basis oftheoretical analysis, this paper researches and analyses synthetically the stabilityof the waste dump in Tunlan mine formed by filling gully and flating from thetheoretical analysis, field measurement and numerical simulation of threeaspects and has made some achievements.By implementing site research and investigation about the waste dump inTunlan mine, and reviewing the relevant literature, collected the geologicalcondition, geomorphology, climatic characteristic, satellite image, physical andmechanical parameters and hydraulic parameters of gangue dispersions etc,which does preparations for the research and analysis of waste dump’s stability. By studying granular mechanics, obtained the dynamic and static shear strengthand deformation characteristic of granular media. By establishing mathematicaland mechanical model of rock slope, and derivating mechanical model formula,obtained the safety factor formula which can determine the stability of the slopeand the factors that affect slope stability are the stress state parameters of slope,slope height and slope angle, severe, cohesion, internal friction angle of rockand soil mass constituting its structure. By using total station and RTK forregularly monitoring the measuring line and measured pile of waste dump inTunlan mine, and analyzing the measured datas, obtained that the slope edgeregion deformation of Tunlan waste dump base is greater than the inner region.And the deformation in the vertical direction is larger than the deformation inthe x direction, the deformation in the x direction is larger than the deformationin the y direction. Meanwhile, the deformation of Tunlan waste dump base isvery small, which shows that Tunlan waste dump is overall steady. By usingGeoStudio software simulating the stability of Tunlan waste dump before andafter casing in the natural state and under rainfall, obtained that the stability ofwaste dump after casing is less little than that before casing. With increasing ofrainfall and the increase of rainfall intensity, the pore water pressure, volumetricwater content, horizontal displacement, vertical displacement, maximum shearstrain are increasing, and the safety factors are decreasing. When the rain last90d, if rainfall intensity is24mm/d, waste dump is in a steady state. If rainfallintensity is45mm/d, waste dump is in the limit equilibrium state, and if rainfall intensity is90mm/d, waste dump is in the unstable state. By contrastinghorizontal and vertical displacement and pore water pressure change, obtainedvertical deformation of Tunlan waste dump is greater than horizontaldeformation. And the rate of increase of pore water pressure of waste dumpbefore casting is greater than that after casting. Besides, pore water pressure atthe bottom of the waste dump after casing is almost unchanged, the bottom ofwaste dump before casing appears saturated zone, in contrast, it does not appearsaturated zone after casing.This paper researches and analyzes Tunlan waste dump stability underdifferent conditions by theoretical analysis, field measurements and numericalsimulation methods, obtained systematically Tunlan waste dump stability underdifferent conditions, which provides a reference for the further land reclamationand crop. The study has a reference to the stability of other waste dump undersimilar conditions across the country.