Effective Stress in Rock


Gray Ian (2017). Effective Stress in Rock. Deep Mining 2017 – J Wesseloo (ed.) © 2017 Australian Centre for Geomechanics, Perth, ISBN 978-0-9924810-6-3

This paper looks at what is the meaning of effective stress in rock and how it is measured. The paper examines the field measurement of stress in intact and jointed systems including fluid pressure and how it acts within the matrix and joints. How the fluid pressure acts varies between rock types and structure. The processes of stress measurement by overcoring and hydrofracture are considered and the benefits and deficiencies of each system discussed. The determination of Biot’s poroelastic coefficient and how this relates to a fractured system are discussed. The importance of effective stress on failures within rock are considered.

Keywords: stress, fluid, pressure, rock, effective, poroelastic, joints, Biot

Author: Ian Gray
Ian initially worked in Australia supervising the installation of the first gas drainage system at Central Colliery and then went on to work as Senior Geotechnical engineer building a mining wing to the consulting company DJ Douglas and Partners. In 1990 he became Principal Engineer, Mining Research with the Safety In Mines Testing and Resarch Station of the Department of Resource Industries of the Queensland Government. In this role he worked on frictional ignitions, mine explosions, windblasts, gas drainage and directional drilling including the first surface to in-seam operation in the country in 1991. In 1994 he started Sigra as a one man business. Since then the company has grown under his guidance to span mining, gas, civil, geotechnical work and a number of mechanical and electronic product developments.

1 Comment

  • Dear Dr. Ian Gray
    How are you, I hope you and everything are fine. We met few years ago at Brisbane at ACG conference. I am interested in the research you posted, Kindly can you send me a copy of it. I am involved in some tunnels suffer from effective stresses cracks in the lining concrete. it’s a long story, we can discuss it.
    Best regards
    Prof. Bahaaeldin Sadagah

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