The Heterogeneity Study Of The Particle Size Distribution And Permeability Of The Waste Dump

The seepage law of internal water of waste dump, which is the basic factor ofits internal pollutant dissolution, release rate and its stability, but due to the specialstructure of coal gangue and the waste dump’s form of piling and dumping, theinternal particle size distributed nonuniform, which determines permeabilityheterogeneity of waste dump. This in turn made the seepage field distributionshows unique regularity.This paper starting from the physical and mechanic of waste dump, analysisof gangue granular particle size, gradation characteristic, accumulationcharacteristics and movement characteristics of coal gangue, on the basis:（1） Through the permeation experiments of different gradation of coalgangue, research and analysis of the permeability of coal gangue（2）Characteristicing gradation characteristics of gangue particle size by fractaldimension. And design some specific gradations for the experiment. Through thesimulation experiments, we establish the relation curves between the fractaldimension and coefficient of permeability, and use it to calculate the coefficient ofpermeability for each area of waste dump. Obtain that: the internal penetration characteristics present heterogeneous.the value of permeability coefficient betweenthe two neighbor layers up to1-2order of magnitude difference.（2） Piled similar simulation experiment of waste dump, analysischaracteristics of particle size distribution in the waste dumpThrough the similar simulation experiment of waste dump, analysischaracteristics of particle size distribution, the results show that: the internal ofwhole waste dump could be divided into three parts: the smaller size of coalgangue mainly distribute on the upper area, the medium-size of coal ganguelocated in the central region and the base gangue is the larger size of coal gangue.Based on this, using image processing function of Matlab painting drillings,building the three-dimensional geological model based on Kriging interpolationmethod.Finally based on the above two experimental, using its obtain of waste dumplayered geometry model and its permeability coefficient, numerical simulationanalysis of the flow movement to the homogeneous and heterogeneous model.Comparative analysis showed that: the seepage field distribution has the obviousdifference between homogeneous model and heterogeneous physical models. Thepore pressure of homogeneous model presented linear decrease with heightincreasing. While pore pressure distributed nonuniform in heterogeneous model,and on the variation interface of permeability coefficient formed pore pressure accumulation zone or vaporize district.