1. Professor and Holder of the Buchanan Chair, Dept. of Civil Engineering, Texas A&M Univ., College Station, TX 77843-3136.
2. Geotechnical Engineer, Kleinfelder Inc., 3601 Manor Rd., Austin, TX 78723.
3. Graduate Student, Dept. of Civil Engineering, Texas A&M Univ., College Station, TX 77843-3136.