Experimental Investigation on Anisotropic Strength and Deformation Behaviors of Columnar Jointed Rock Mass in Confined State

Abstract

Columnar jointed rock mass (CJRM) has a special joint structure formed during the cooling of lava. The self-oriented joint structure can induce mechanical anisotropy of the rock mass, which poses a challenge for geotechnical engineering. To understand the mechanical properties of CJRM, conventional triaxial compression tests were conducted on the artificial CJRM specimens. It can be found from the experiment results that the orientation of columns has a distinct impact on the strength and deformation modulus. Four failure modes of CJRM specimens at different dip angles of columns under different confining pressures can be observed. The anisotropy degree in strength and deformation modulus is estimated, where it is found that the increase of confining pressure decreases the anisotropy in strength and increases the anisotropy in deformation modulus.