ISSN: 0149-6115
Published Online: 1 December 2008
Page Count: 13

Development of a Direct Simple Shear Apparatus for Peat Soils

Boylan, Noel
Ph.D.,University College Dublin,

Long, Michael
Senior Lecturer,University College Dublin,

(Received 11 February 2008; accepted 17 October 2008)

Abstract

This paper discusses the design and development of a new direct simple shear (DSS) apparatus for testing peat soils. The apparatus has been designed to test peat at low effective stresses, representative of its in situ condition and allow the deformation of the specimen to be monitored. This device uses particle image velocimetry (PIV) image analysis techniques to monitor the side of the peat specimen and provide an insight into the behavior of peat during shearing. A set of comparative tests on reconstituted clay have been conducted with another widely used DSS apparatus and has shown both to yield similar undrained strength ratios (s^u/σ^vc′) for a range of stress levels. Application of the apparatus to peat soils is demonstrated by a set of tests on a high water content blanket bog peat. Analysis of these tests using the PIV technique reveals the complex shear strain and volumetric strain behavior of peat undergoing shearing. Identification of partial slippage of a specimen is also shown through these analyses.

Keywords:
peats, organic soils, direct simple shear, laboratory testing, image analysis, particle image velocimetry

Paper ID: GTJ101703
DOI: 10.1520/GTJ101703
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