1. School of Highway, Chang’an University, South Erhuan Middle Section, Xi’an 710064, China
2. School of Highway, Chang’an University, South Erhuan Middle Section, Xi’an 710064, China (Corresponding author), e-mail: wanghnchd@gmail.com, http://orcid.org/0000-0001-9268-8073
3. Department of Civil Engineering, Monash University, Clayton, VIC 3800, Australia
4. Department of Civil and Environmental Engineering, Michigan Technological University, 1400 Townsend Dr., Houghton, MI 49931, USA