1. Postdoctoral Fellow, Institute of Geotechnical and Underground Engineering, Huazhong Univ. of Science and Technology, Wuhan 430074, China; and Key Laboratory of Highway Construction and Maintenance Technology in Loess Region, Shanxi Transportation Research Institute, Taiyuan 030006, China.
2. Professor, Institute of Geotechnical and Underground Engineering, Huazhong Univ. of Science and Technology, Wuhan 430074, China (corresponding author).
3. Postdoctoral Fellow, State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430074, China.