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为确定抽放钻孔的卸压范围,建立了考虑煤的塑性软化和扩容特性的钻孔周围煤体弹塑性模型,得到了钻孔周围煤体的应力分布和卸压范围的表达式,利用Comsol软件对建立的数学模型进行求解,对比分析了软硬煤层钻孔的应力分布特征,找出了抽放钻孔卸压范围的影响因素.研究结果表明:在研究钻孔周围煤体的受力特征时,应考虑煤的塑性软化和扩容特性;软煤层钻孔具有更好的卸压效果,硬煤层钻孔更易形成应力集中;煤体硬度、埋藏深度和钻孔孔径是控制钻孔卸压范围的主要影响因素.
In order to determine the pressure relief range of drainage borehole, an elastic-plastic model of coal around the borehole considering the plastic softening and expansion characteristics of coal was established. The stress distribution and the expression of pressure relief range of the coal around the borehole were obtained. Comsol software was used to solve the mathematical model and the stress distribution characteristics of the hard and soft coal seam were analyzed and compared to find out the influencing factors of the pressure relief range of the drainage borehole.The results show that in studying the influence of the coal body around the borehole The characteristics of plasticity and expansion of coal should be taken into consideration when considering the mechanical characteristics of coal. The soft coal seam has better pressure relief effect and the hard coal seam is more likely to form stress concentration. The hardness, burial depth and bore diameter of coal seam are the key points for controlling drilling and unloading Pressure range of the main factors.