Experimental study on the fracture and damage characteristics of dry and saturated argillaceous slate under microwave irradiation

Microwave-assisted rock breaking is an effective method to solve the problems of low efficiency and serious cutter wear in hard rock excavation, which has broad application prospects. In this study, experiments were conducted on the burst and pre-burst damage characteristics of dry and water-saturated bedded slate under microwave irradiation. The results show that both types of slate burst along bedding planes; higher microwave power leads to shorter burst time, and water-saturated slate bursts faster under the same working conditions. Microwave irradiation can significantly deteriorate the mechanical properties of slate. The P-wave velocity of specimens at 0° decreases more obviously than that of 90° specimens. The uniaxial compressive strength (UCS) of slate drop markedly with the increase of microwave power and irradiation duration, and water-saturated specimens suffer more severe performance degradation. The UCS of the slate displays significant anisotropy. The uniaxial compression failure mode of slate is dominated by bedding structure, and microwave irradiation has no obvious effect on its fracture morphology. The damage of slate caused by microwave irradiation is mainly related to factors such as the mineral composition and water-bearing condition of the rock.