Characterizing Low Plastic Fine-Grained Foundation Soils under Strong Earthquake Shaking

This paper describes a field and laboratory testing program conducted on the relatively weak, low plastic fine grained soils within a dam foundation. Standard Penetration Tests (SPTs) with energy measurements and Nilcon vane shear tests were conducted in situ and consolidation, triaxial and constant volume direct simple shear tests (DSS) were conducted on intact soil samples extracted from the low plastic fine grained soil layers. The DSS tests included cyclic and post-cyclic monotonic tests with and without initial static bias. The seismic behaviour of the low plastic fine grained soil layers were characterized based on their plasticity index, over consolidation ratio, SPT resistance, vane shear strengths and cyclic and post-cyclic resistance from the DSS tests, with emphasis on the results from the DSS tests. The paper presents results from the field and laboratory testing focusing on the results from cyclic and post-cyclic DSS tests.

Thavaraj, T., G. Stevenson, J. Williams and D. Siu. 2013. “Characterizing Low Plastic Fine-Grained Foundation Soils under Strong Earthquake Shaking,” in: GeoCongress 2013, Stability and Performance of Slopes and Embankments III, San Diego, California, March 3-6, 2013. Reston, Virginia: American Society of Civil Engineers.

If you are interested in obtaining this publication, please email  We may be able to provide you with a copy, depending on copyright restrictions. For more papers visit the technical publications page.