Fracture characteristics and energy evolution analysis of pre-cracked granite under uniaxial compression based on a 3D-Clump model

•A novel three-dimensional Clump (3D-Clump) numerical model of pre-cracked granite was proposed.•The relative errors of peak strength and elastic modulus are below 5.00% between numerical simulation and laboratory test.•The crack distribution characteristics and failure modes of numerical simulation are in good agreement with the laboratory test.•After the peak point, the elastic strain energy rapidly releases, the dissipation energy and the microcrack growth rate rapidly increase.