1. College of Geological Engineering and Geomatics, Chang’an University, Xi’an 710054, China
2. Key Laboratory of Western China′s Mineral Resources and Geological Engineering, Ministry of Education, Chang′an University, Xi′an 710054, China
3. Department of Geotechnical Engineering, College of Civil Engineering, Tongji University, Shanghai 200092, China
4. Key Laboratory of Geotechnical and Underground Engineering of the Ministry of Education, Tongji University, Shanghai 200092, China