Study On Numerical Simulation Of Mechanical Response And Creep Characteristic For Coal-pillar In Thick Seam Mining

The underground mining is an important way to acquire the mineral resources in our country currently. The mining area of the environment is constantly changing, increasingly mined-out area, and the stability of stope is more important with the face of mining completed in the deep coal mining. The coal-pillar is a pivotal stope unit and it supports stope, so, it not only ensures stability of roof beam and wall rock, but also stability coal-pillar increases the mining rate of coal body obviously. Among them, the coal rock body flows is to determine the long-term pillar of strength, is fundamental evaluation of mining an important basis for long-term stability. The paper carried out the research deeply and systematicly on the creep characteristics of the coal rock in the thick seam of coal mining, long-term strength and damage features, and the coal rock structure and confining pressure changes and time dependence. The specific contents are as follows:(1) In the coal-pillar mechanical response, summarized the various basic theories of the coal-pillar strength and deformation law, comprehensive analysis the coal-pillar destruction mechanism, getting that the coal-loading and strength is the coal-pillar stabilities analytical foundation.(2) Evolution through coal theoretical study, it is determined for the deep coal seam to adopt the improvement Burgers model-cvisc model as the coal-rock creep model. Preliminary study on the time factor to the stability of coal-pillar.(3) With the main 3-thick coal seam in Xinglong Coal Mine as the study object, using FLAC^3D achieve the numerical simulation of the mining process, keep the view ground announce to public the distribution condition of the cover and coal-pillar, in displacement, stress and knuckling under area. Through summary of stress and strain law of the coal-pillar and analysis of long-term stability, reproduction the process of deformation and damage of the cover rock and coal in mining area, while initially discussing the destroy characteristic of the coal-pillar at the same time.(4) According to creep theoretical analysis, build the corresponding creep model, combining the experimental results identified the coal-rock creep parameters. And then using numerical simulation of coal to accept the long-term strength index and evaluate it.(5) Through study the creep characteristic of coal-pillar, select the stress, strain and state zone for the evaluation, determine the stability of coal-pillar in distroct, providing guidance and protection bases for coal mining and mining stope stability after maintaining.In fact, the deformation of mining rock, breaking, moving entire dynamic mechanical process is one kind of the flowing deformation learning phenomenon having a characteristic alone completely. And be only analyzing the various deformation of stope from elastic-plastic aspect currently still. This paper passes to treat the coal-rock as visco-plasticity, making use of numerical analysis to get necessary conditions and parameters with keeping coal-pillar stability, providing theory and actuality directive function for the long-term stability analysis in subsidence area.