Seminar - Behrooz Ghahreman-nejad - Thermo-Mechanical Behaviour of Clay: Stress-Strain Response

Wednesday, August 13, 2003, 1.10 - 1.50 pm
Civil Engineering Lecture Room 3

Abstract

The influence of temperature on soil strength and stiffness is still one of the most controversial issues surrounding the subject of thermo-mechanical behaviour of soils. A number of drained and undrained triaxial tests have been conducted on normally consolidated (NC) and over consolidated (OC) samples of M44 clay and Kaolin C1C at temperatures ranging from 22°C to 100°C. Direct displacement measuring devices have been successfully used for the first time to measure axial and lateral displacements of clay samples during tests at various temperatures. In the seminar the effects of temperature on shear strength and stiffness, stress strain responses for different consolidation histories, the Cam Clay and critical state parameters are presented by comparing the results at various temperatures. It has been discovered that shear strength, friction angle and initial small strain stiffness reduce at elevated temperature. The slope of the swelling line in the v p' plane, k, has been found to reduce with temperature. The slope of the isotropic normal consolidation line (INCL) and critical state line (CSL) in the v p' plane, l, have been found to be independent of temperature, but both the INCL and the CSL shift downwards to lower locations as temperature increases whereas the slope of the critical state line in the q-p' plane, M, reduces with temperature rise.