The effect of the dip angle of an interlayer coal seam on rock mass mechanical behavior and damage characteristics is seldom discussed. To address the lack of the existing research, a numerical simulation was conducted using the Particle Flow Code (PFC2D), and its damage to mechanical behavior, acoustic emission (AE)characteristics, and damage characteristics were analyzed. The outcomes exhibit the peak strength and elastic modulus of coal-rock combinations are between that of rock and coal. As the coal inclination angle rises, the elastic modulus and peak strength gradually decrease. AE model experiences the initial growth period, stable growth period, and rapid decline period. The value of AE hits and the generation of the AE signal is affected by the size of the inclination angle. The degree of damage to the coal-rock combination gradually rises as the angle rises. The damage process of the coal and rock composite sample encompasses an initial damage phase, damage stable evolution phase, accelerated damage phase, and a failure phase. The damage values of the stable evolution stage for varying dip angle models are also different. As the inclination angle increases, the damage value gradually increases, while the strain at the same damage value gradually decreases.

Roof cutting is an effective technique for controlling the deformation and failure of the surrounding rock in deep gob-side entry. The determination of the roof cutting parameters has become a popular research subject. Initially, two mechanical models are established for the non-roof-cutting and roof-cutting of gob-side entry in deep mining conditions. On this basis, the necessity and significance of roof cutting is revealed by analysing the stress and displacement of roadside prop. The Universal Distinct Element Code numerical simulation model is established to determine the key roof-cutting parameters (cutting angle and cutting height) according to the on-site situation of No. 2415 headentry of the Suncun coal mine, China. The numerical simulation results show that with the cutting angle and height increase, the vertical stress and horizontal displacement of the coal wall first increase and then decrease, as in the case of the vertical stress and displacement of roadside prop. Therefore, the optimum roof cutting parameters are determined as a cutting angle of 70° and cutting height of 8 m. Finally, a field application was performed at the No. 2415 headentry of the Suncun coal mine. In situ investigations show that after 10 m lagged the working face, the stress and displacement of roadside prop are obviously reduced with the hanging roof smoothly cut down, and they are stable at 19 MPa and 145 mm at 32 m behind the working face, respectively. This indicates that the stability of the surrounding rock was effectively controlled. This research demonstrates that the key parameters determined through a numerical simulation satisfactorily meet the production requirements and provide a reference for ensuring safe production in deep mining conditions.