Energy Evolution and Cracking Mechanism of Pre-Cracked 3D Printing Rock Mass

3D printed rock specimens with different fracture inclination angles were designed and fabricated using photosensitive resin as raw material. Uniaxial compression tests were carried out and combined with Digital Image Correlation (DIC) technique to analyze the damage mode, mechanical properties, energy evolution and rupture mechanism of the specimens. The results showed that the specimens developed shear cracks or tension cracks at the end of the prefabricated fracture under uniaxial compression loading, and the angle of the prefabricated fracture had a significant effect on the damage mode of the specimens; Specimen stress-strain curves were divided into four segments: compression-density, elastic deformation, plastic deformation and damage segments; The specimen peak stress and elastic modulus achieved minimum and maximum values at the crack inclination angle of 22.5° and 90°, respectively; The energy evolution curve of the specimen is divided into 5 segments: compression-density energy dissipation, linear energy storage, energy jump accumulation, elastic strain energy release and energy dissipation segments; Uneven strain regions exist in the specimen at the beginning of loading, and high strain bands appear regularly as the load increases; the cracking angles of the upper and lower wings of the specimen are similar and decrease regularly with the increase of the prefabricated fracture inclination; The larger the distortion energy of the specimen, the weaker the bearing capacity.