Abstract: In this paper, on-site monitoring, theoretical analysis and numerical simulation were used to study the strata pressure behavior and “O-X” failure law of roof under complex geological conditions in Da’anshan coal mine. Roof caving characteristic and strata pressure behavior in No.13 coal face of Da’anshan coal mine were studied through ground pressure monitoring system. Additionally, based on the field monitoring data, numerical model was established to study the formation, evolution and fracturing law of roof plastic zone during mining process. The results show that the support resistance in the middle of working face is significantly greater than those in the upper and lower parts. During the weighting period, the average length of stress concentration in the gateways is 12.17 m and 9.46 m respectively ahead of the face, and the corresponding maximum pressure is 24 MPa and 23.57 MPa respectively. In addition, the“O-X”fracture structure was obtained through numerical simulation and theoretical analysis. The first weighting and periodic weighting steps obtained by numerical simulation are basically consistent with the on-site monitoring.

Key words: roof breakage, on-site monitoring, strata pressure behavior, numerical simulation