1. Assistant Professor, School of Geoscience and Environmental Engineering, Southwest Jiaotong Univ., Chengdu 611756, China.
2. Dean, School of Engineering, Univ. of Virginia, Charlottesville, VA 22904 (corresponding author).
3. Professor Emeritus, Geological Engineering, Civil and Environmental Engineering, Univ. of Wisconsin-Madison, Madison, WI 53706.