Effect of confining pressure on mechanics and deformation behavior of sandstone containing a single inclined joint

Abstract

The mechanics behaviors, failure modes and acoustic emission characteristics of rectangular green sandstone specimens containing a single joint with various inclination degree under different confining pressure have been determined in this article. The samples were tested over a confining pressure range of 0 to 40 MPa, and the inclination of the joint was varied between 0° and 50°. The test results indicated that: Mohr–Coulomb criterion is fit to peak strength of intact samples and residual strength of jointed samples with 40°. But the peak strength of jointed sample with 40° increases nonlinearly with confining pressure, which can be fitted by Hoek–Brown criterion. And the confining pressure has a reduction effect on anisotropy for jointed rock. When the inclination angle was less than 40°, the joint has a small negative influence on the strength and deformation of the jointed sample, as the inclination angle increased from 40° to 50°, a drop decrease in peak strength and Young’s modulus can be observed. The failure modes can be classified into T-mode, S-mode and SD-mode. Finally, the evolution laws of AE count for green sandstone specimens has been discussed.