煤矿灾害动力学与控制国家重点实验室自主研究课题2011DA105287-MS201208;中央高校基本科研业务费资助No.CDJXS12201106.This work was supported by the Scientific Research Foundation of State Key Lab.of Coal Mine Disaster Dynamics and Control2011DA105287-MS201208;the Fundamental Research Funds for Central Universities of ChinaCDJXS12201106