1. Institute of Geotechnical Engineering, Southeast University, Nanjing, Jiangsu 210096, China
2. State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei 430071, China
3. Department of Mathematics and Information Science, Wenzhou University, Wenzhou, Zhejiang 325035, China