YU, LI-YUAN, SCHOOL OF MECHANICS AND CIVIL ENGINEERING, STATE KEY LABORATORY FOR GEOMECHANICS AND DEEP UNDERGROUND ENGINEERING, CHINA UNIVERSITY OF MINING AND TECHNOLOGY, XUZHOU 221008, PR CHINA
YU, LIYUAN, STATE KEY LABORATORY FOR GEOMECHANICS AND DEEP UNDERGROUND ENGINEERING, CHINA UNIVERSITY OF MINING AND TECHNOLOGY, XUZHOU 221116, PR CHINA