1. College of Civil Engineering, Fuzhou University, Fuzhou350108, P. R. China
2. Department of Civil Engineering, McMaster University, Hamilton, OntarioL8S3L8, Canada
3. Fujian Provincial Expressway Technology Consulting Co., Ltd., Fuzhou350108, P. R. China
4. Key Laboratory of Highway Construction and Maintenance Technology in Loess Region of Ministry of Transport, Shanxi Transportation Technology Research & Development Co., Ltd., Taiyuan030032, China