Journal Published Online: 06 July 2021
Volume 44, Issue 6

Measuring Seismic Shear Strengths for Bootlegger Cove Clay



This article presents an evaluation of the undrained shear strengths for Bootlegger Cove Clay (BCC) in the Anchorage, Alaska area for seismic stability and permanent deformation analyses for public and private infrastructure. Given the high seismicity of the area, the focus herein is on measuring and selecting undrained strengths that reflect the effects of cyclic loadings and level of permanent displacement predicted to occur. The laboratory cyclic test results herein show that BCC will mobilize at least 80 % of the static peak undrained shear strength (∼20 % reduction) if field permanent displacements are less than 0.1 m. If field displacements are between 0.1 and 1.0 m, BCC will mobilize an undrained shear strength in between the static peak and residual undrained strengths in addition to the 20 % reduction for the effects of cyclic loading. If field permanent displacements are greater than 1.0 m, the BCC will mobilize the static residual undrained strength. Recommendations for field vane shear and laboratory shear tests are presented for measuring these undrained shear strengths.

Author Information

Stark, Timothy D.
Department of Civil Engineering, 2217 Newmark Civil Engineering Lab (MC-250), University of Illinois, Urbana, IL, USA
Pages: 28
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Stock #: GTJ20200240
ISSN: 0149-6115
DOI: 10.1520/GTJ20200240