Experiment of Anisotropic Axial Extension of Clay Rock
Clay rocks have the advantages of extremely low permeability,self-sealing potential of fractures,and high sorption ca-pacity,and are thus chosen as a potential geological barrier for underground disposal of radioactive waste.In order to study the influ-ence of bedding plane on the peak strength,failure mode and elastic modulus of clay rocks,a series of axial extension(AE)cyclic loading and unloading tests were carried out for specimens with different bedding angles.The AE test was performed by increasing the radial stress and decreasing the axial stress at the same time under constant mean stress.The experimental results show that the peak axial strength of clay rocks is related to the bedding plane.The peak strength of clay rocks reaches the maximum in the direction parallel to and perpendicular to bedding,and the lowest in the direction the angle between drilling core and bedding direction θ=45 °.The strength curves of specimen with different bedding angles show U shape.The characteristics of the axial peak strength of clay rock can be described well by the rock breaking criteria at different angles.The failure pattern of clay rock also varies with bedding plane,the samples are mainly tensile fracture,while the compressive failure occurs at θ=45 °.The elastic modulus shows great difference in different bedding angles,and the parallel and vertical directions of bedding are obviously larger than other directions.
万方数据
维普
