1. Lecturer, School of Civil and Architectural Engineering, Shandong Univ. of Technology, Zibo 255000, China (corresponding author).
2. Undergraduate Student, School of Civil and Architectural Engineering, Shandong Univ. of Technology, Zibo 255000, China.
3. Senior Engineer, Road Research Centre, Zhejiang Scientific Research Institute of Transport, Hangzhou 310039, China.