Beijing Key Laboratory of Accurate Mining of Co-associated Energy, China University of Mining and Technology-Beijing
School of Emergency Management and Safety Engineering, China University of Mining and Technology-Beijing
Faculty ofSafety Science and Engineering, Civil Aviation University of China
Mine Safety Technology Branch, China Coal Research Institute

The deformation and failure characteristics of coal around gas drainage boreholes in deep soft and low permeabilitycoal seams affect coal seam gas pre-drainage. Based on the condition of non-uniform stress field, the mechanicalmodel of borehole disturbed coal mass was developed, the analytical solutions of stress, strain and displacement in thedamaged zone, plastic zone and elastic zone of borehole disturbed coal mass were deduced, the influence law of factorssuch as lateral pressure coefficient, load condition, cohesion and hole expanding behavior on the “three zone” distribution of disturbed coal mass were analyzed, and the reliability of the theoretical model was verified through engineering examples.The results show that under the condition of non-uniform stress field, the plastic zone and damaged zone of disturbedcoal mass are elliptical distribution. With the increase of lateral pressure coefficient, the length of the upper andlower wings of the plastic zone and damaged zone of disturbed coal mass becomes larger and larger, and the radius of theplastic zone and damaged zone in the direction of smaller stress is greater than the radius of the two zones in the directionof large stress. The radius of plastic zone and damaged zone of coal mass increases with the increase of vertical load, anddecreases with the increase of initial cohesion and residual cohesion. The influence of vertical load on its shape can be ignored.When the borehole diameter is expanded from 0.1 m to 0.5 m, the coal mass 0−1.0 m away from the borehole centerproduces a strong disturbance, the coal mass 1.0−4.6 m produces a weak disturbance, and the coal mass after 4.6 m hasalmost no influence. Through the field example of No.16032 bottom pumping roadway hydraulic reaming in the Guhanshancoal mine, it is observed that the disturbed coal mass in the reaming section has a high degree of damage. Based onthe coal output, the reaming diameter is deduced to be 1.5 m, and then the deformation and damage characteristics ofdrilling reaming coal mass are obtained through theoretical calculation and numerical simulation respectively. The two arein good agreement, so as to verify the reliability of the theoretical model.

国家自然科学基金资助项目(51974321，52130409)；国家自然科学基金创新研究群体资助项目(52121003)

徐超，秦亮亮，王凯，等. 非均匀应力场瓦斯抽采钻孔扰动煤体变形破坏特征[J]. 煤炭学报，2023，48(4)：1538−1550

XU Chao，QIN Liangliang，WANG Kai，et al. Deformation and failure characteristics of gas drainage drilling-reaming coal mass in non-uniform stress field[J]. Journal of China Coal Society，2023，48(4)：1538−1550