Direct Shear Testing of Polished Slickensided Surfaces
Christopher L. Meehan1; Thomas L. Brandon2; J. Michael Duncan3; Binod Tiwari4
1Assistant Professor, University of Delaware, Dept. of Civil and Environmental Engineering, 301 DuPont Hall, Newark, DE 19716, U.S.A.
E-mail: cmeehan@udel.edu (corresponding author)
2Associate Professor, Virginia Tech, Dept. of Civil and Environmental Engineering, 200 Patton Hall, Blacksburg, VA 24061, U.S.A.
E-mail: tbrandon@vt.edu
3Univ. Distinguished Professor, Virginia Tech, Dept. of Civil and Environmental Engineering, 200 Patton Hall, Blacksburg, VA 24061, U.S.A.
E-mail: jmd@vt.edu
4California State University, Fullerton, Dept. of Civil and Environmental Engineering, 800 N. State College Blvd. E-419, Fullerton, CA 92834, U.S.A.
E-mail: btiwari@fullerton.edu
Landslides, 2010, Volume 7, Number 2, pp. 157-167
Abstract
A series of ring shear and direct shear tests were performed to measure the drained residual strength of three clay soils. For each of the soils, slickensided direct shear specimens were prepared by wire-cutting intact specimens, and polishing the resulting shear plane on a variety of surfaces to align the clay particles in the direction of shear. Drained direct shear tests were then conducted on each of the polished specimens. The resulting shear strengths were compared with the residual strengths measured in the ring shear device to evaluate the effectiveness of the different polishing techniques for creating slickensided surfaces. Test results indicated that the measurement of residual strengths along preformed slickensided surfaces is extremely sensitive to both the soil type and the slickenside preparation technique that is used. Consequently, this approach does not appear to be a viable alternative to conventional repeated direct shear or ring shear tests to measure residual shear strengths.
Keywords
Direct shear tests; Torsion; Clay; Residual strength; Shear strength; Laboratory test
Reference
Meehan, C. L., Brandon, T. L., Duncan, J. M., and Tiwari, B. (2010). “Direct Shear Testing of Polished Slickensided Surfaces.” Landslides, Journal of the International Consortium on Landslides, Springer, 7(2), 157-167. (doi:10.1007/s10346-010-0199-7)