Evaluation of Normalized Pore Water Pressure vs. Accumulated Unit
Energy Relationships
for Determining Liquefaction Potential in Soils
Matthew S. Wallin
(msw@po.cwru.edu)
and
Department of Civil
Engineering
Case Western Reserve
University
Cleveland, OH 44106-7201
Over the past three decades
researchers have struggled to better understand the phenomenon of soil
liquefaction which has been responsible for catastrophic failures the world
over. Extensive effort has been exerted
to determine liquefaction’s mechanism(s), its influential factors, and to
develop a method for predicting a soil deposit’s susceptibility to
liquefaction-induced failure. Over the
past ten years, researchers at Case Western Reserve University have had much
success with unit energy-based approaches.
The current research addresses the development, and validation through
centrifuge testing, of relationships to predict the buildup of excess pore
water pressure in a soil deposit, given the time history of accumulated unit
energy.
The relationships are obtained from the analysis of data obtained through extensive experimental programs conducted by Liang (1995), Rokoff (1999), and Dief (2000), as well as the author. Performed on three different soils, the testing procedures included both torsional shear and centrifuge testing, and encompassed three levels of relative density and effective confining pressure. Regression analysis was used to determine normalized pore water pressure vs. accumulated unit energy relationships for all soils and levels of effective confining pressure from the torsional shear test data. These expressions were then shown to make valid predictions of pore pressure development when compared to results obtained from centrifuge testing.