ISSN: 1945-7545
CODEN: GTJODJ
Page Count: 5

Investigation of Boundary Friction Effects in Polyaxial Tests

Demiris, CA
Professor of engineering geology, Aristotle University, Thessaloniki,

Abstract

Development of boundary friction forces is a common problem in testing of materials, such as rock and concrete. This article reports on experimentations with different friction reducing pads, aiming at diminishing the side friction effects in polyaxial tests. This appears technically possible by using special Teflon®-grease pads, with optimum lubrication achieved at high pressures. Ineffective lubrication can cause an apparent increase of strength and Young's modulus. The volumetric changes under polyaxial stress states appear relatively little affected by boundary friction, contrary to the partial volume changes of ΔV₂ and ΔV₃.

Keywords:
polyaxial tests, rocks, boundary friction, friction reducers, volumetric change

Paper ID: GTJ10937J
DOI: 10.1520/GTJ10937J
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