Experimental study on tensile and shear strength of anthracite under supercritical CO2

Abstract

In the process of CO2 geological sequestration, the mechanical properties of coal will be changed after supercritical CO2 interacts with coal. Based on this, in this paper, Brazilian splitting test and variable angle shear test were carried out on anthracite under different test conditions, and the changes of tensile strength, shear peak strength, residual strength, internal friction angle and cohesion of coal under different test conditions were studied and compared from two aspects of dry/saturated moisture content and supercritical CO2 soaking time(3, 5, 7 days). The results show that the tensile strength, shear strength and residual strength of coal decrease with the increase of supercritical CO2 soaking time, but the decreasing amplitude decreases gradually; the degradation effect of mechanical parameters of coal under the action of water + supercritical CO2 is greater than that of drying test group; the internal friction angle and cohesion tend to decrease with the increase of supercritical CO2 action time, but the effect of supercritical CO2 on cohesion is more obvious, but the effect of internal friction angle is less