1. College of Civil Engineering, Chongqing Univ., Chongqing 400045, P. R. China (corresponding author).
2. College of Civil Engineering, Chongqing Univ., Chongqing 400045, P. R. China; and Key Laboratory of New Technology for Construction of China in Mountainous Areas, Chongqing Univ., Chongqing 400045, P. R. China; and Chongqing Vocational College of Architectural Engineering, Chongqing 400039, P. R. China.
3. College of Civil Engineering, Chongqing Univ., Chongqing 400045, P. R. China.