ISSN: 1945-7545
CODEN: GTJODJ
Published Online: 29 January 2008
Page Count: 4

Measuring “Fast” Shear Strengths Along Slickensided Surfaces in the Bromhead Ring Shear

Meehan, Christopher L.
Assistant Professor, University of Delaware, Department of Civil and Environmental Engineering, Newark, DE

Brandon, Thomas L.
Associate ProfessorUniversity Distinguished Professor, Virginia Tech, Dept. of Civil and Environmental Engineering, Blacksburg, VA

Michael Duncan, J.
Associate ProfessorUniversity Distinguished Professor, Virginia Tech, Dept. of Civil and Environmental Engineering, Blacksburg, VA

(Received 25 June 2007; accepted 2 December 2007)

Abstract

Fast and slow ring shear tests were performed in the Bromhead ring shear device to examine the effect of the displacement rate on the shear strength measured along slickensided discontinuities in Rancho Solano Fat Clay. For each test, initial drained shearing was performed at a displacement rate of 0.018 mm/min, fast shearing was performed at a rate of 44.5 mm/min, and drained shearing was recommenced at a displacement rate of 0.018 mm/min. Significant variations in measured post-peak shear strengths were observed, and problems with the pore pressure response in the soil surrounding the slickensided plane are discussed. As a result of these problems, it was concluded that fast Bromhead ring shear tests may not be suitable for evaluating the effects of fast shearing on the strengths of slickensided surfaces.

Keywords:
ring shear tests, clays, residual strength, slickensides, fast shearing, laboratory test

Paper ID: GTJ101325
DOI: 10.1520/GTJ101325
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