1. School of Civil Engineering, Chongqing University, 174 Shazheng Street, Shapingba District, Chongqing 400045, P. R. China
2. Key Laboratory of Construction and New Technology of Mountainous Region Cities, Chinese Ministry of Education, Chongqing University, 174 Shazheng Street, Shapingba District, Chongqing 400045, P. R. China