1. Lecture, School of Civil and Hydraulic Engineering, Xichang Univ., Xichang, Sichuan 615013, China.
2. Professor, School of Civil and Hydraulic Engineering, Xichang Univ., Xichang, Sichuan 615013, China (corresponding author).
3. Professor, School of Civil and Hydraulic Engineering, Xichang Univ., Xichang, Sichuan 615013, China.