不同高度比煤岩组合体的力学特性及裂纹演化数值模拟

Numerical simulation of mechanical properties and crack evolution of coal-rock combination with different height ratios

为探究不同高度比煤岩组合体的力学特性和裂纹演化规律,利用UDEC数值模拟软件,开展了煤岩高度比分别为2∶1、1∶1、1∶2的“煤-岩”组合体模拟试验。研究结果表明:不同高度比煤岩组合体的强度均介于煤、岩单体强度之间,且煤岩高度比越小,组合体的抗压强度越大,两者之间呈负相关;随着煤体所占比例的减小,组合体煤体部分从倾斜45°角破坏转为“N”型破坏,岩体部分保持较好的完整性;组合体的裂纹演化可以分为裂纹平稳发育阶段、裂纹快速发育阶段以及残余破坏阶段,裂纹主要集中在煤体部分,并且逐渐积累发育扩展到上部岩体,最终造成组合体的失稳破坏。

This paper intends to investigate the mechanical properties and crack evolution of coal-rock assemblages with different height ratios.The study conducts the simulation experiments of "coal-rock" assemblages with height ratios of 2∶1,1∶1 and 1∶2 by using UDEC numerical simulation software.The results show that the strength of coal-rock assemblages with different height ratios is between coal monomer strength and rock monomer strength,and the smaller the coal-rock height ratio is,the greater the compressive strength of the assemblage is,as shows a negative correlation.alone with the proportion of coal body decreasing,the coal body part of the assemblage changes from damage inclined 45° to "N" with better wholeness of the rock.The crack evolution of the assemblage can be divided into smooth crack development stage,rapid crack development stage and residual damage stage,with the cracks mainly concentrating in coal body part and gradually accumulating and expanding to the upper rock body,which eventually causes the instability of the assemblage.