1. Ph.D. Candidate, School of Transportation and Logistics, Southwest Jiaotong Univ., Chengdu 611756, PR China.
2. Professor, School of Civil Engineering and Geomatics, Southwest Petroleum Univ., Chengdu 610500, PR China (corresponding author).
3. Graduate Student, School of Civil Engineering and Geomatics, Southwest Petroleum Univ., Chengdu 610500, PR China.