1. State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and Technology No. 1, Daxue Road Xuzhou Jiangsu 221116 P. R. China
2. School of Mechanics and Civil Engineering China University of Mining and Technology No. 1, Daxue Road Xuzhou Jiangsu 221116 P. R. China
3. Research Centre for explosion mechanics and blasting technique China University of Mining and Technology No. 1, Daxue Road Xuzhou Jiangsu 221116 P. R. China