1. School of Highway, Chang’an Univ., Xi’an, Shaanxi 710064, China (corresponding author).
2. Professor, School of Highway, Chang’an Univ., Xi’an, Shaanxi 710064, China.
3. China Road and Bridge Engineering Co., Ltd., No. 88 C, Andingmenwai Ave., Beijing 100011, China.
4. School of Highway, Chang’an Univ., Xi’an, Shaanxi 710064, China.