Experimental Study on the Influence of Faults on the Roof Stress Characteristics During Deep Coal Seam Mining

To investigate the influence of geological structures on the stress characteristics of the roof under mining conditions, similar material physical models were designed for an intact roof, a roof with a reverse‐tilt fault, and a roof with a normal‐tilt fault. The coal mining process was simulated, respectively, and the influence of faults on the stress characteristics of the immediate roof, main roof, and coal pillar was obtained. The results indicate that the pressure accumulation in the coal pillar of the models with faults is delayed compared to the model with an intact roof under the mining process, and the normal‐tilt fault has a more significant impact than the reverse‐tilt fault. The rate of pressure accumulation in the coal pillar, from fastest to slowest, occurs in the model with a reverse‐tilt fault, followed by the intact roof model, and then the model with a normal‐tilt fault. The maximum accumulated pressure in the coal pillar of the model with a reverse‐tilt fault is ~1.7 times and 1.5 times that of the intact roof model and the model with a normal‐tilt fault, respectively. The reverse‐tilt fault has a significant impact on the stress characteristics of the immediate roof. A stress relief phenomenon occurs near the fault, while stress concentration is observed at both ends of the mining face. The stress at both ends is ~2 times as high as the stress near the fault. Compared to the intact roof, a reverse‐tilt fault is more favorable for pressure accumulation in the main roof, while a normal‐tilt fault can weaken the pressure accumulation. In the model with a reverse‐tilt fault, the maximum pressure in the main roof occurs near the fault, measuring ~25 MPa, while in the model with a normal‐tilt fault, the maximum pressure in the main roof is located in the middle of the coal mining face after crossing the fault, measuring ~15 MPa. The research results can provide a basis for the safe mining and the prevention of dynamic disasters of deep coal.