Investigation of 3D Printing Sand Core Technology on the Mechanical Behaviors of Soft–Hard Interbedded Rock Masses

Three-dimensional (3D) printing has been increasingly applied to experimental research in geotechnical engineering. In this paper, standard cylinder specimens with high and low strength were prepared using 3D-printing sand core technology. The elastic–plastic and rheological mechanical behaviors were experimentally studied. In addition, the similarity and limitations were verified through comparison with natural sandstone, slate, sand–gypsum, claystone, etc. On this basis, a new way to prepare soft–hard interbedded layered rock in geotechnical mechanics was developed. Considering the features of layered rock and the principle of 3D printing, cylindrical and cubic specimens of soft–hard interlayered rock mass with different inclination angles were prepared by controlling the binder content layer by layer. The deformation and strain differences between the soft and hard phases were verified through digital image correlation. In this case, the anisotropic failure evolution mode of soft–hard interbedded rock mass was revealed by the images captured. The structural anisotropy behaviors of 3D-printed soft–hard interbedded rock was also studied. The results agree well with the published experimental and theoretical results. This study introduces a broad prospect of 3D printing sand core technology for future experimental mechanical research on a soft–hard interbedded layered rock mass in geotechnical engineering.