Study Of Surface Subsidence Law By Strip-partial Extraction Under Thick Loose Overburden

This paper based on deeply investigating and arrangement analysising the engineering geological characteristics of correlation thick loose overburden mining areas, combined with the related achievement of the double-layer model theory and compounded model theory by strip-partial extraction under thick loose overburden etc, put forward the three-layer engineering geological model by strip-partial extraction under thick loose overburden. Namely hypostasis bedrock layer (major control layer)-the deep clay layer(mild control layer )-upper loose layer (soil and sand interbed layer). Then according to a certain mining area practical example, set up the numerical model of the strip-partial extraction under thick loose overburden. Furthermore, using the ANSYS10.0 large finite element simulation software, studied the stress and displacement change of overlying strata by strip-partial extraction under thick loose overburden, obtained the general law of overlying strata and surface subsidence by strip-partial extraction under thick loose overburden, analysised the influence of the deep clay layer to "two-band" development. Thoroughly analyzed the effect factors of surface subsidence by strip-partial extraction under thick loose overburden, using the orthogonal analysis, carrying out a nine-factors, four-levels perpendicularity test with mining depth, exploiting thickness, extraction ratio, the mining width, specific gravity of the loose overburden to overlying strata and elastic modulus, poisson ratio, agglutinate force, and internal friction angle of the coal seam, obtained the influence sensitive degree of each effect factor to the surface subsidence and the ordering of influence role grade, then offered some suggestions to design of the strip-partial extraction under this geological conditions. Eventually, in view of the specific gravity of the loose overburden to overlying strata having a great influence to surface subsidence, based on part aggravated principle, research the special law of surface and overlying strata subsidence under thick loose overburden ultrathin bedrock, the field engineering example showed that the simulation result is essential consistent to measured results, taking a few theoretical guidances for the production practice.