“顶板-煤层”结构体冲击倾向性演化规律及力学特性试验研究

针对单纯以煤层或顶板岩层进行煤层冲击倾向性判定存在"低估"问题,以典型的冲击危险矿井为背景并结合煤层赋存的实际情况和冲击地压的显现特征,建立"顶板-煤层"结构体模型。通过对纯煤层、顶板岩层及2种不同高度比下的"顶板-煤层"结构体冲击倾向性试验和不同顶板强度、厚度、均质性及接触面角度的冲击倾向性数值试验,研究不同顶板特性对"顶板-煤层"结构体冲击倾向性的影响。研究发现,"顶板-煤层"结构体冲击倾向性高于纯煤层或岩层测定结果,更接近实际。随着顶板强度、厚度、均质性的增加,"顶板-煤层"结构体冲击倾向性增强,随接触面角度的增大,其单轴抗压强度降低,峰后塑性变形阶段越来越明显。在接触面角度一定的情况下,随着顶板岩体强度的增加,随"顶板-煤层"结构声发射累计释放能量减弱。随"顶板-煤层"结构体冲击倾向性的增强,其峰后声发射累积能量呈减小的趋势。

Experimental research on rules of rock burst tendency evolution and mechanical properties of “roofcoal”structure body

Rock burst tendency as a index for coal rockburst dangerous evaluation，it is sometimes under/over estimate the stability of coal and rock.The model of “roofcoal” structure body was built base on the coal seam hosting and the characteristics of rockburst behavior.With the rockburst tendency experiment of “roofcoal”structure body on coal，rock and two different height ratio and the numerical simulation test to research different roof strength，homogeneity，interface angle to the structure burst tendency.It is shown that the rockburst tendency index of “roofcoal” structure body higher than single coal or single rock and more closer to practice.With the strength，the height，the heterogeneity index of rock increasing，the rockburst liability of “roofcoal”structure body becomes stronger.The rock burst tendency index increase and the combined body whole strength decrease for the interface angle increasing，the postpeak plastic deformations is more obvious.When the interface angle in a certain，the accumulative AE energy decrease for the roof strength increasing.In addition，the rockburst tendency index more stronger，the accumulative AE energy of “roofcoal” structure body weaker during the phase of plastic deformation.