Study On "Four-zone" Models Of Mining Strata And Surface Movement

The mining damage and environmental problems caused by traditional mining modehave become increasingly prominent.“Green Mining” of coal has become the direction ofscience mining. Mastering the mathematical laws and mechanical mechanism of strata andsurface movement caused by coal mining, establishing the mathematic and mathancis modelof strata and surface movement based on“Strata Collapse—Strata Movement and Deformation—Surface Subsidence”, bringing about the overall prediction of strata and surface movementwhich have very important significance of enriching the control theory and promotingpractice of mining subsidence.In this paper, through the theoretical analysis, mathematical model, similar simulationverification by measurement and other means, the mathematic and mechanic model of miningstrata and surface movement has been systematicly studied under level and nearly level coalmining condition.By summarizing the characteristics、laws and the relationship between strata and surfacemovement.Based on the integerated process of “Stratum Collapse—Stratum Movement andDeformation—Surface Subsidence”, the characteristic of each stratum movement zone hasbeen described. In the same time, the fracture zone is divided into “Quasicontinuous Zone”and “Block Articulated Zone”, so the four zones division of “Caved zone、QuasicontinuousZone、Block Articulated Zone、Continuous Deformation Zone”has been putted forward. Alsothe strata movement transferration condition and the height determination method of eachzone have been given. At last, the overall framework model of strata and surface movementalso is put forward.Based on the formation process of caved zone.Considerring the time effect of rock swellcoefficient and rock void content of caved zone strata, the dymanic change of caved zoneheight has been discribed by fractal geometry.In connection with the non-continuous feature and the blocks articulated characteristics, the mathematic and mechanic model of block articulated zone movement has been built up bythe discontinuous deformation analysis theory (DDA), the specific calculation process alsohas been given.Considering the influence of fissures on the uniaxial compressive strength、therelationship between the rock elastic modulus and the uniaxial compressive strength. Thefractal geometry relationship between elastic modulus and fracture has been deduced, theelastic plate movement model of quasicontinuous zone has also been established.As far as continuous deformation zone is concerned, considering the key strata effect, theelliptical table model of single stratum deformation in continuous deformation zone and thesuperposition criterion of strata deformation have been putt forward. The movementdeformation models of continuous deformation zone and the whole overburden strata havealso been established. The prediction formulae of different excavation space have also beenderived.Finally, through engineering examples to demonstrate the model, the rationality andeffectiveness of the model has been proved.