1. Mechanics Engineering Deptartment, Shijiazhuang Tiedao University, Shijiazhuang, China
2. School of Civil Engineering, Shijiazhuang Tiedao University, Shijiazhuang, P.R. China
3. The Hebei Province Technical Innovation Center of Safe and Effective Mining of Metal Mines, Shijiazhuang Tiedao University, Shijiazhuang, China
4. Mechanics Engineering Department, Shijiazhuang Tiedao University, Shijiazhuang, P.R. China