ISSN: 1945-7545
CODEN: GTJODJ
Page Count: 10

Pore-Water Pressure Buildup in Clean Sands Because of Cyclic Straining

Ladd, RS
Laboratory director and laboratory supervisor, Wood-ward-Clyde Consultants, Clifton, NJ

Dobry, R
Professor of civil engineering, Rensselear Polytechnic Institute, Troy, NY

Dutko, P
Laboratory director and laboratory supervisor, Wood-ward-Clyde Consultants, Clifton, NJ

Yokel, FY
Senior research civil engineer, Center for Building Technology, National Bureau of Standards, Gaithersburg, MD

Chung, RM
National Academy of Engineering, Washington, DC

Abstract

The prediction of pore-water pressure buildup in sands caused by undrained cyclic loading is one of the key items in evaluating the potential for liquefaction of sandy sites during earthquakes. Presented herein are data indicating that, in strain-controlled tests, there is a predictable correlation between cyclic shear strain, number of cycles, and pore-water pressure buildup; this correlation is much less sensitive to factors, such as relative density and fabric than comparable results obtained from stress-controlled tests. Also, there is a threshold cyclic shear strain below which there is no sliding at the contacts between sand particles, and essentially no pore-water pressure buildup occurs. The data indicate that, for clean sands, this threshold shear strain, as well as the pore-water pressure buildup for strains slightly above the threshold, are basically independent of relative density, grain size distribution, fabric, and method of testing (triaxial and direct simple shear). However, both threshold shear strain and pore-water pressure buildup do depend on the overconsolidation ratio.

Keywords:
cyclic strain, damping ratio, earthquake engineering, laboratory testing, liquefaction, pore-water pressure, sands, shear modulus, shear strain, threshold shear strain

Paper ID: GTJ10677J
DOI: 10.1520/GTJ10677J
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