LAUSR

Rocks with bedding or foliation usually behave as anisotropic body. Understanding the full-field displacement characteristics of anisotropic rocks is of particular interest, since the behaviors of anisotropic rocks vary with the angle between bedding and loading direction, and are thus more difficult to predict than isotropic rocks. By the digital image correlation technique, the two-dimensional displacement fields of a bedded limestone with different bedding angles are obtained in this paper. Displacement field evolution process with loading is described in detail, in which the progressive rotation of principal strains can be identified. The displacement field pattern also varies with loading angle. If some threshold of loading angle is surpassed, the pattern can transit from one to another, which is essentially determined by the tensor transformation rule of compliance matrix. The non-coaxiality between principal strains and stresses with respect to different loading angles are calculated from both test results and numerical simulation, which further confirms the validity of transverse isotropy—a fundamental assumption for rocks exhibiting layered structure.