受底板承压水影响的下保护层开采厚度确定

针对淮南潘谢矿区煤层条件建立了采动煤岩体计算模型,在分析顶、底板煤岩受力后裂隙分布特征基础上,通过数值模拟的方法研究了保护层A3煤层不同开采厚度时,采空区上方的B4-1煤膨胀变形量及本煤层底板导水破坏深度变化规律;随着开采厚度不断增大,B4-1煤层膨胀变形量呈指数函数趋势增加,并在采厚2～3 m之间有突变过程;在承压水水压降为1.0 MPa情况下,随开采厚度增加,底板采动破坏深度与之呈现对数曲线关系。在保证保护层A3煤层对被保护层B4-1煤层能充分卸压及在承压水体上安全回采的前提下,最后得出A3煤层理论上最佳开采厚度为2.21～4.0 m。

Determination of Mining Thickness of Lower Protective Seam Affected by Floor Confined Water

According to the seam conditions of Panxie Mining Area in Huainan,the paper establishes computational model of mining coal and rock.On the basis of analyzing coal and rock crack distribution characteristics,through the numerical simulation,the paper studies the change laws of B4-1 coal expansion deformation above goaf and the coal seam floor failure depth with different thickness of A3 protective seam;With the increasing of mining thickness,B4-1coal seam expansion deformation shows exponential function tends,and behaves mutations when mining thickness is between 2 m and 3 m;in the cases of largest confined water pressure of 1.0 MPa,floor failure depth shows the logarithmic curve with the increase of mining thickness.Under the premise of that the protective layer A3 can fully release protected seam B4-1 and coal seam A3 can be mined successfully and safely above the floor confined water,the conclusion that the A3 theory mining thickness will be among 2.21~ 4.0 m is drew.