含冰裂隙砂岩力学行为及D-P强度准则修正OA

In cold-region rock engineering,ice-filled fractures significantly weaken the mechanical properties of rock masses,which severely impacts the safety and stability of projects.To investigate the mechanical behavior and failure mechanisms of ice-filled fractured rock masses,uniaxial compression tests,acoustic emission monitoring,and discrete element numerical simulations were conducted in this study.On this basis,the mechanical properties and failure mechanisms of ice-filled fractured sandstone were systematically examined,with a focus on how fracture thickness(5-30 mm)and dip angle(0°-90°)influenced rock mass strength,elastic modulus,energy evolution,and crack propagation.The results show that compressive strength,elastic modulus,and pre-and post-peak energy all decrease non-linearly with the increase in fracture thickness,among which the elastic modulus drops by 20％-34％.The fracture dip angle was found to dominate the classification of failure modes.Vertical fractures(90°)exhibit the highest strength(23.56 MPa)due to efficient stress transfer,while low-angle fractures(15°-30°)experience a 30％-45％reduction in strength due to interface shear effects.Three failure modes were identified:ice layer crushing(α≤ 15°),interface slip(15°-75°),and rock main fracture(α≥75°).A micro-parameter system for the ice-rock composite medium was developed based on the PFC discrete element model,achieving over 90％agreement between simulation results and experimental data.By considering the coupling effects of fracture thickness and dip angle,the D-P strength criterion was modified,and the theoretical values deviate from experimental data by less than±5％These findings provide theoretical support for the stability evaluation and disaster prevention in cold-region rock engineering and lay the groundwork for studying ice-rock interaction mechanisms in complex freeze-thaw environments.