Abstract
As a naturally heterogeneous material, the mechanical behavior of rock mass is predominantly governed by its internal fractures. Among these, cross-cutting cracks exhibit notably distinct mechanical responses and energy dissipation mechanisms compared to single fissures, primarily due to their complex geometric configurations. In this study, uniaxial compression tests combined with Digital Image Correlation (DIC) technique were conducted to systematically investigate the mechanical properties and energy dissipation mechanisms of sandstone specimens containing cross-cutting cracks with varying inclination angles. The results demonstrate that the presence of cross-cutting cracks significantly deteriorates the mechanical performance of sandstone: both the peak strength and elastic modulus generally decrease with increasing crack angle, and a remarkable strength reduction of 60.15% is observed in specimens with 150° cracks. Furthermore, the crack inclination angle plays a controlling role in the energy dissipation mechanism. The failure of specimens with 30°-60° cracks is dominated by the abrupt release of accumulated elastic strain energy, exhibiting typical brittle characteristics. In contrast, the failure of specimens with 120°–150° cracks is characterized by a dissipation energy-dominated progressive process, where the energy dissipation ratio at peak stress increases significantly from 11.66% for the 30° specimens to 48.76% for the 150° specimens. Finally, the evolution of strain fields captured by DIC reveals that the crack intersection zone acts as the core area for energy dissipation and strain localization, controlling the coalescence process of macroscopic fracture surfaces and considerably reducing the overall bearing capacity of the specimens. This study elucidates the energy dissipation mechanism of cross-cutting cracked sandstone and its control effect on the failure mode, providing both theoretical and experimental foundations for stability assessment of fractured rock masses in engineering practice.