瓦斯抽采是矿井瓦斯防治的主要技术手段，煤层透气性是影响抽采效果的关键因素，CO₂预裂爆破作为一种低透气性煤层的新型增透方式，相较传统炸药爆破有很大优势，但存在炮孔起裂能量耗散较大，起裂方向不易控制，导致起裂范围有限等不足，影响致裂效果，通过在气爆孔预制楔形切槽能较好解决这类问题，因此对含楔形切槽气爆致裂的研究显的尤为重要。

本文采用理论分析、实验室试验及数值模拟相结合的方法，研究CO₂气爆作用下含楔形切槽孔周煤体的表面裂纹扩展规律。基于气爆冲击理论，构建CO₂气爆含楔形切槽力学模型，分析切槽尖端应力强度因子和位移场，确定气爆裂纹的起裂、止裂判定条件，以最小应变能密度准则确定裂纹沿切槽方向起裂。利用自主搭建的CO₂气爆实验平台，实验室开展静载压力(0.5MPa、1.0MPa、1.5MPa)和气爆压力(1.2MPa、1.8MPa、2.4MPa)正交组合下有无切槽试样的CO₂气爆试验，利用非接触式应变测量系统获取煤体破坏的图像序列，计算不同条件下的孔周裂纹张开位移和表面位移，分析试样表面裂纹扩展规律，对比验证切槽对气爆能量的导向作用。采用ANSYS/LS-DYNA有限元数值模拟软件，利用流固耦合算法模拟有无切槽条件下的气爆情况，研究气爆应力波的传播过程，发现含楔形切槽气爆应力波的扩散在切槽方向具有明显优势，而远离切槽的孔周其他区域应力分布与无切槽孔时的应力分布类似，表明切槽对应力波有显著的导向作用；煤体质点振动位移在切槽方向显著增加，气爆能量在切槽尖端集中，煤体损伤更易在切槽方向产生，减少了因钻孔壁围岩粉碎造成的能量浪费，保护孔周围岩少受或不受气爆破坏，使更多能量倾向煤体深部的主裂纹通道扩展，扩大钻孔的围岩裂隙范围。

论文的研究丰富了CO₂气爆致裂基础理论，阐明含楔形切槽CO₂气爆的煤体裂纹扩展特征规律，对CO₂气爆增透强化抽采技术的增效提能提供了理论依据，具有重要的工程指导意义。

Gas extraction is the main technical means of mine gas control, coal seam permeability is a key factor affecting the extraction effect, CO₂ pre-fracture blasting as a new type of low permeability coal seam to increase the permeability, compared with traditional explosives blasting has great advantages, but there is a large energy dissipation from the gun hole initiation, fracturing direction is not easy to control, resulting in limited fracturing range and other shortcomings, affecting the fracturing effect, these problems can be better solved by pre-fabricating wedge-shaped grooves in the air blast holes, so the study of airburst fracturing with wedge-shaped grooves is particularly important.

In this paper, the method of combining theoretical analysis, laboratory test and numerical simulation is used to study the surface crack propagation law of the coal body with wedge-shaped notch under the action of CO₂ gas explosion. Based on the gas explosion impact theory, a mechanical model of CO₂ gas explosion with wedge-shaped grooving was constructed, the stress intensity factor and displacement field of the grooving tip were analyzed, the conditions for the initiation and arrest of gas explosion cracks were determined, and the minimum strain energy density criterion was used to determine the crack edge. Cracks in the grooving direction. Using the self-built CO₂ gas explosion experimental platform, the laboratory carried out the orthogonal combination of static load pressure (0.5MPa, 1.0MPa, 1.5MPa) and gas explosion pressure (1.2MPa, 1.8MPa, 2.4MPa) with or without grooved samples. In the CO₂ gas explosion test, the non-contact strain measurement system was used to obtain the image sequence of coal failure, and the crack opening displacement and surface displacement around the hole under different conditions were calculated. Directing of energy. The ANSYS/LS-DYNA finite element numerical simulation software was used to simulate the gas explosion condition with or without cutting grooves by using the fluid-structure coupling algorithm, and the propagation process of the gas explosion stress wave was studied. The grooving direction has obvious advantages, and the stress distribution in other areas around the hole far from the grooving is similar to the stress distribution in the hole without grooving, indicating that the grooving has a significant guiding effect on the stress wave; the vibration displacement of coal mass points in the grooving direction Significantly increased, the gas explosion energy is concentrated at the tip of the cutting groove, and the coal damage is more likely to occur in the cutting groove direction, reducing the energy waste caused by the crushing of the surrounding rock on the borehole wall, and protecting the surrounding rock from the hole or from the gas explosion. The multi-energy tends to expand the main crack channel in the deep part of the coal body and expand the surrounding rock crack range of the borehole.

The research of this paper enriches the basic theory of CO₂ gas explosion cracking, clarifies the characteristic law of crack propagation in coal body with wedge-shaped notch CO₂ gas explosion, and provides a theoretical basis for the efficiency enhancement and energy improvement of CO₂ gas explosion and enhanced permeability extraction technology. Important engineering guidance.

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