Analysis on the influence of thrust nappe structure on coal and gas outburst in Huainan Coalfield

In order to improve the prevention and control of coal and gas outburst under the condition of geological structure belt in Huainan Coalfield, the relationship between thrust nappe structure and coal and gas outburst was studied by means of theoretical analysis, the geometric and dynamic characteristics of thrust nappe structure, as well as the coal structure, gas occurrence and tectonic stress under the control of the structure were analyzed respectively in Huainan Coalfield. The results show that the thrust nappe structures in Huainan Coalfield are mainly distributed in the north and south margins of the coalfield, it is formed by the North China Craton and the Yangtze Craton in the Indosinian-Yanshan period under the collisional compression. The thrust nappe structure is napped from south to north, and the thrust nappe structure of the northern margin is napped from north to south, forming a tectonic system with reverse phase back inclination. The development of tectonic coal and high gas content in thrust nappe structure in Huainan Coalfield provide material conditions for coal and gas outburst. The high tectonic stress and gas pressure provide the dynamic conditions for coal and gas outburst. From the perspective of impact of thrust nappe structure on coal and gas outburst, this paper analyzes the causes of "1.5" coal and gas outburst accident in Wangfenggang Coal Mine, the analysis shows that in the C₁₃ coal seam where the accident occurred, the tectonic coal is developed, the gas content is large and the tectonic stress is concentrated, when the C₁₃ coal seam is uncovered in the main well construction, the original stress equilibrium state is broken, and a large amount of coal and gas gush out, leading to the accident.