Discussion of "Seismic Compression of Two Compacted Earth Fills Shaken by the 1994 Northridge Earthquake" by Jonathan P. Stewart, Patrick M. Smith, Daniel H. Whang, and Jonathan D. Bray

The authors have attempted to document the response to earthquake at two compacted earth fill sites that were shaken by a significant earthquake in 1994. Both fills consisted of cohesive soils with 43 to 69% plastic fines. The authors represented that the ground surface displacements from seismic compression for both sites were known or were accurately estimated from pre- and postearthquake surveys. In analyzing each fill's response to earthquake, the authors used the procedure developed by Tokimatsu and Seed (1987) for clean sand. In the paper, the authors acknowledged that this method is not appropriate for analyzing the clayey fills at the two sites studied; nonetheless, they stated that the method represents the current state of practice even for fill containing cohesive fine-grained soils.