Abstract: To explore the rock damage mechanism under microwave irradiation and the influence of strong waveabsorbing mineral content on the effect of microwave irradiation on fracturing rocks, basalt is selected as the research object and the discreteelement program particle flow code is used to establish a microscopicstructure analysis model based on numerical calculation for ternary medium basalt composed of ilmenite, diopside, and plagioclase. The influence of the content variation of strong waveabsorbing mineral (ilmenite) on the initiation and development of basalt cracks and the strength weakening effect after microwave irradiation is examined under the irradiation conditions of high power and short time. The results show the following: (1) A large number of intergranular cracks occurred first at the junction between strong waveabsorbing minerals and relatively weak waveabsorbing minerals inside the basalt, and then, some intergranular cracks gradually expanded and passed through the minerals with the shortest connecting path to form transgranular cracks. (2) The intergranular cracks were mainly concentrated at the ilmeniteplagioclase junction, while the transgranular cracks were mainly distributed in ilmenite and diopside. (3) The basalt sample produced damage with uneven distribution, enhancing the rock toughness. Furthermore, with increasing ilmenite content, the peak strength and elastic modulus of the basalt sample significantly decreased, the stressstrain curve fluctuation increased, and the peak generation point advanced. Moreover, the degree of strength weakening of the basalt sample was directly proportional to the ilmenite content, which is a strong waveabsorbing mineral.

Key words: assisted rock breaking, microwave irradiation, basalt, strong waveabsorbing mineral, strength weakening, cracking mechanism