Anisotropic creep behavior of soft-hard interbedded rock masses based on 3D printing and digital imaging correlation technology

Three-dimensional (3D) printing technology is increasingly used in experimental research of geotechnical engineering. Compared to other materials, 3D layer-by-layer printing specimens are extremely similar to the inherent properties of natural layered rock masses. In this paper, soft-hard interbedded rock masses with different dip angles were prepared based on 3D printing (3DP) sand core technology. Uniaxial compression creep tests were conducted to investigate its anisotropic creep behavior based on digital imaging correlation (DIC) technology. The results show that the anisotropic creep behavior of the 3DP soft-hard interbedded rock mass is mainly affected by the dip angles of the weak interlayer when the stress is at low levels. As the stress level increases, the effect of creep stress on its creep anisotropy increases significantly, and the dip angle is no longer the main factor. The minimum value of the long-term strength and creep failure strength always appears in the weak interlayer within 30°–60°, which explains why the failure of the layered rock mass is controlled by the weak interlayer and generally emerges at 45°. The tests results are verified by comparing with theoretical and other published studies. The feasibility of the 3DP soft-hard interbedded rock mass provides broad prospects and application values for 3DP technology in future experimental research.