As part of the reconstruction of Interstate 90 in Seattle, Washington, WSDOT designed and supervised the construction of a geosynthetic reinforced soil (GRS) retaining wall located on Rainier Avenue, Seattle. The Rainier Avenue wall had a maximum height of 12.6 m and supported a nearly 6-m-high surcharge fill. At the time it was constructed, it was the highest GRS wall in the world. The wall was extensively instrumented and monitored during and after construction to evaluate its face deflections and the strain levels occurring in it.
To define the actual stress distribution occurring in the Rainier Avenue wall, a two-phase research project was conducted by the University of Washington. Phase I included an extensive laboratory test program that used a newly developed plane strain device. Numerical analysis and modeling of the results of the instrumentation and laboratory tests constituted Phase II.
The major tasks of the Phase II project were to (1) analyze the test result of the unit cell device (UCD), a plane strain GRS element testing device developed in Phase I; (2) develop numerical models of the Rainier Avenue Wall using both material properties and test results of the UCD; and (3) using the results of tasks 1 and 2, develop a methodology for analyzing the working stress-strain distribution in the GRS retaining structures.
The Phase II project was conducted from September 1995 to December 1997. During this period, two research programs were conducted simultaneously. One program concentrated on analyzing the UCD test results, and the other on developing the numerical models of the Rainier Avenue wall. Significant results were obtained from both research programs. Products of the Phase II research include an elasticity model that is capable of analyzing GRS behavior, compsosite properties of GRS elements, and four numerical models of the Rainier Avenue wall. Improved understanding of the working stress-strain distribution inside GRS retaining structures was also obtained with these products.