1. Associate Professor, School of Qilu Transportation, Shandong Univ., Jinan 250061, PR China.
2. Professor, School of Qilu Transportation, Shandong Univ., Jinan 250061, PR China (corresponding author).
3. Researcher, Shandong Hi-Speed Group Co. Ltd., Aoti West Rd., Yinfeng Fortune Plaza, Jinan 250101, PR China.
4. Senior Engineer, Shandong Hi-Speed Group Co. Ltd., Aoti West Rd., Yinfeng Fortune Plaza, Jinan 250101, PR China.
5. Postgraduate, School of Qilu Transportation, Shandong Univ., Jinan 250061, PR China.