Experimental study on influence of confining pressure on shale mechanical properties under high temperature condition
Abstract：High temperature conventional triaxial compression test of shale were carried out by using the MTS815 ser- vo-controlled testing machine, based on the results of the tests, the relationships between confining pressure and the characteristic of shale stress-strain curve, peak strength, elastic modulus, Poisson' s ratio, peak strain were investigated, and the general regulation is obvious. According to the characteristics of volumetric strain, the stress-strain curves were classified into three types. They are dilatation type, compression-dilatation type, compression type, and the confining pressure has conspicuous dilatation effect on shale. At the same temperature, when confining pressure rises from 5 MPa to 25 MPa, shale peak strength (σ1- σ3 ) is comparatively lower, indicating stronger plastic deformation, and peak strength and elastic modulus increase with uprising confining pressure. When confining pressure is lower than 15 MPa, shale Poisson' s ratio increases with increasing confining pressure while peak axial strain and peak circle strain decreases with increasing confining pressure. When confining pressure is higher than 15 MPa, shale Poisson' s ratio decreases slightly with the increasing confining pressure, while peak axial strain and peak circle strain increase slightly with the increasing confining pressure.
Keywords：confining pressureshalemechanical propertieshigh temperature conventional triaxial compression testvolumetric strain
Publication Date：2012-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：5( 1829-1833 )