Correlation between cutting parameters of roadheader-bolters and tensile anisotropy of coal

Integrated excavation and bolting construction represents the developmental direction for intelligent and efficient tunneling in coal seam roadways. Drum cutting parameters serve as first-hand data for perceiving changes in coal mass properties, and understanding their correlation with the mechanical properties of coal is the theoretical foundation for achieving intelligent perception during tunneling. Tensile anisotropy, a typical mechanical characteristic of coal, significantly impacts rock breaking and support design. With the aid of the particle discrete element method, tensile anisotropy in coal models was achieved through an "equivalent interlayer" structure. Meanwhile, controllable adjustment of coal tensile anisotropy along the drum cutting direction was realized by coupling the drum and coal models. On this basis, five sets of dynamic cutting experiments were performed to analyze the variation characteristics of drum torque and cutting resistance signals during the cutting process and ultimately reveal the influence of coal tensile anisotropy on cutting parameters of roadheaders-bolters. The following beneficial conclusions were drawn. As the angle between the downward cutting direction of the drum and the loading direction of the minimum tensile strength narrows, drum torque increases while torque fluctuation is gradually suppressed, with the amplitude decreasing from 6,209 N·m to 5,491 N·m. The cutting resistance signals reflect a seesaw relationship between coal "compaction" and drum deceleration phenomena, and coal exhibits three distinct stages: "overall disturbance → disturbance dissipation → localized failure". Higher alignment between the downward cutting direction of the drum and the loading direction of the minimum tensile strength results in stronger vibration response of coal to cutting and more intense localized failure effects.