Dynamic characteristics analysis of periodic weighting under different advancement speeds based on microseismic-ground pressure coupled monitoring

To investigate the influence mechanism of advancement speed on periodic weighting in a fully mechanized longwall face, the 22,116 working face was taken as the engineering background. By integrating microseismic monitoring, online support resistance monitoring, and key stratum theory, the characteristics of roof fracturing and ground pressure behavior under different advancement speeds were systematically analyzed. The research indicates: (1) The 23.0-m thick fine-grained sandstone of the Datong Formation acts as a sub-key stratum, controlling the movement of its overlying strata approximately 70 m thick. (2) The cyclic advance rate variation (increasing from 3.2 to 7.4 m/day) triggered a structural transition in the overlying strata from an arched configuration to a beam-like structure, resulting in a substantially increased periodic weighting interval of 37%. (3) When the working face maintained a continuous advance rate of no less than 6.8 m/d, the cantilever beam fracture pattern was consistently stable. Under these operational conditions, the microseismic energy release intensity increased significantly. UDEC numerical simulations further confirmed this phenomenon, revealing an increase in the stress peak exceeding 33.0%. The findings provide a theoretical basis for roof disaster prevention and control and the optimization of intelligent mining parameters.