【摘要】 分别从三维离散单元法及非线性动力学方法两个角度研究了坚硬顶板的运动规律,得到了较一致的结论。坚硬顶板的初次垮落具有冲击性,应力水平较高,该阶段的LE1为负值,系统处于有序的定常态;所研究条件下实施防冲措施的最佳时机在第2阶段开采活动结束之前,可促使坚硬顶板从冲击性整体运动向周期性分段运动转化;∑(+LEi)表明第4阶段的混沌程度最高,对应应力水平适中的周期性运动阶段。研究表明,除了初次冲击性垮落阶段,坚硬顶板运动系统在其它阶段均处于孕育着变化的混沌态。更多还原

【Abstract】 The moving features of a hard roof are studied by three-dimensional discrete element method and nonlinear dynamics; and some conclusions are obtained. The movement of hard roof at the first time is impacted and with high level of stresses; but the system of moving hard roof is an ordered steady state at the phase because value of LE1 is negative. The best chance to prevent rock burst under certain conditions is before the end of the second extracted phase, which can change the movement of hard roof from impact to periodicity. And ∑(+LEi) states that chaotic degree of the forth phase is the highest according to periodic movement of hard roof, of which the stress level is middle size. Results of the study present that system of moving hard roof is chaotic and producing alteration apart from the first impacted phase.更多还原