1. Professor, Dept. of Civil and Structural Engineering, Univ. of Sheffield, Mappin St., Sheffield, S1 3JD, U.K.
2. Senior Geotechnical Engineer, Jacobs UK Ltd., Simpson House, 6 Cherry Orchard Rd., Croydon, Surrey, CR9 6BE, U.K.
3. Professor, Dept. of Urban and Civil Engineering, Ibaraki Univ., 4-12-1 Nakanarusawa, Hitachi, Ibaraki 316 8511, Japan.