(1.Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Engineering(China University of Mining and Technology), Xuzhou 221116, Jiangsu, China; 2.School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China; 3.School of Civil Engineering, Southwest Jiaotong University, Chengdu 610031, China)
TU502+.6