Abstract

With the continuous increase in coal mining depth in China, dynamic disasters in coal and rock masses caused by the coexistence of high in-situ stress and high gas content have become increasingly frequent, with rockbursts being particularly typical. Taking the 1111(1) working face of the Zhuji Mine in Huainan as the engineering background, this study establishes a dual-variable coupling model of in-situ stress and gas pressure using the RFPA²D numerical simulation platform, and systematically simulates the rockburst evolution process under three typical working conditions: high stress moderate gas pressure, moderate stress–high gas pressure, and combined high stress-high gas pressure. The results show that under the combined high-stress and high-pressure condition, the initial rupture of soft coal is more intense, with the spacing between failure units reduced by 62% compared to single-factor scenarios. Large-scale collapse occurs in the upper part of the coal wall, and gas flow increases by more than 40%. The disaster-causing mechanism is characterized by the synergistic effect of stress waves generated by elastic energy release and the gas-carrying effect induced by gas desorption. Residual hard particles lead to a local stress concentration factor of up to 2.0 (compared to 1.5 in single-condition scenarios). From the perspective of energy driving, gas expansion energy increases exponentially with gas content, promoting the transition of coal movement from sliding friction to rolling friction. Frictional resistance is reduced by 38%, significantly increasing impact velocity and damage intensity. This study, for the first time, reveals the triggering mechanism of rockbursts under the coupling of high in-situ stress and high gas pressure from the perspective of energy transformation and mechanical behavior, providing theoretical guidance and technical support for the prevention and control of dynamic disasters in deep mines.

Keywords:Rockburst; High insitu stress; Gas expansion energy; Coupling mechanism; Numerical simulation