1. Hokkaido University, N10W8, Kita-ku, Sapporo 060-0810, Japan (Email: )
2. Civil Engineering Research Laboratory, Central Research Institute of Electrical Power Industry, 1646 Abiko, Abiko City, Chiba Prefecture 270-1194, Japan
3. NeoScience Co., 5-11-22 Osato, Sennan, Osaka, 590-0526, Japan
4. Geotechnical Center, Oyo Co., 2-61-5 Toro, Saitama, 331-8688, Japan
5. Moscow State University, Moscow, Russia