岩层组合劣化型冒顶机制研究

通过对162起锚杆支护煤巷冒顶事故实例分析研究，顶板岩层组合劣化是引起冒顶事故的主要原因，占事故总数的66 %。应用东北大学岩石破裂过程分析系统（RFPA2D），对不同组合的层状顶板的劣化过程进行了数值模拟研究。通过数值分析可知：岩层组合劣化与顶板岩层组合中软弱夹层位置变化、坚硬岩层厚度及高跨比变化有关；与直接顶板岩层组合中软岩层厚度变化有关。岩层组合劣化破坏的主要是拉破坏、剪切破坏及其共同作用的结果，在剪应力的作用下层状顶板发生整体跨落；在自重应力作用下顶板岩层发生弯曲破坏；剪应力和拉应力共同作用下层状顶板破坏形式为拱形冒落。

Research on roof falling mechanism of deteriorative strata combination supported by bolts

It is known from the analysis and research on 162 roof-falling accidences occurring in coal mining roadway supported by bolts that the deteriorative combination of roof strata is the major reason that accounts for percent 66 of the total accidences.RFPA2d system(the system of rock failure process analysis,developed by Northeastern University) is used to simulate the deteriorative process of different strata combination roof.The result suggest that the deterioration of strata combination is related to the change of soft interlayer positions,the thickness of hard strata,the ratio of height and span,and the thickness change of soft strata in the direct roof.The deteriorative rupture of strata combination results from the tensile failure,shear failure and their mutual action.Under the action of shear stress,the whole roof falls down;under the action of deadweight stresses,flexural failure of roof strata takes place;whereas under the mutual action of shear stress and tensile stress,the failure configuration of the laminated roof strata presents a form of roof-falling arch.