Development of a direct simple shear apparatus for peat

摘要

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 loweffective stresses, representative of its in-situ condition and allow the deformation ofthe specimen to be monitored. This device uses Particle Image Velocimetry (PIV)image analysis techniques to monitor the side of the peat specimen and provide aninsight into the behaviour of peat during shearing. A set of comparative tests onremoulded clay have been conducted with another widely used DSS apparatus and hasshown both to yield similar undrained strength ratios (su/σ'vc) for a range of stresslevels. Application of the apparatus to peat soils is demonstrated by a set of tests on ahigh water content blanket bog peat. Analysis of these tests using the PIV techniquereveals the complex shear strain and volumetric strain behaviour of peat undergoingshearing. Identification of partial slippage of a specimen is also demonstrated throughthese analyses.