煤体自振频率的瓦斯“蚀蠕作用”及其受振损伤激发特征

Blasting vibration, especially resonance, is an important inducement and exacerbation of coal and gas outburst. Understanding of the accurate natural frequency of coal and vibration damage caused by excitation characteristics is the key to determine the optimization goal of the blasting parameters and to prevent coal and gas outburst. The previous work indicated that the natural frequency of coal was related to its stiffness, damping, etc. The erosion effect of the gas makes coal "soften", the stiffness decreases and the damping increases, leading to the slow change of the natural frequency with the adsorption of gas, that is to say, the "corrosion creep effect" of the gas's natural frequency. The confining pressure has the stress strengthening effect on the coal, and will change the boundary condition of the stress wave propagation, which of both affect the vibration damage characteristics of the coal. Combined with the characteristics of coal seam, the project is to use the gas adsorption and natural frequency test system to study the natural frequency characteristics of gas-containing coal. The "creep characteristics" of the natural frequency of coal under the action of gas erosion are obtained, and the microcosmic mechanism of the "corrosion creep effect" is analyzed by infrared spectroscopy. The influence of vibration parameters (i.e. acceleration and frequency) on the excitation effect of the bearing gas containing coal is investigated by using the vibration test system. The evolution law of natural frequency with the damage of coal is analyzed, and subsequently the relationship between the natural frequency change rate and the damage energy and degree of coal are explored. The obtained results contribute to improving the resonance and prevention mechanisms of coal and gas outburst.

爆破振动（特别是共振）是煤与瓦斯突出重要的诱发及加剧因素，掌握准确的煤体自振频率及受振损伤激发特征，是确定爆破参数优化目标、进行共振调控的关键。研究表明，煤岩自振频率与其刚度、阻尼等有关，瓦斯对煤体的蚀损效应使其“变软”、刚度降低、阻尼增大，导致自振频率随瓦斯吸附而缓慢变化，即瓦斯对煤体自振频率的“蚀蠕作用”。围压对煤体有应力强化作用，且将改变应力波传播的边界条件，影响煤体受振损伤特征。结合赋存特征，本项目利用瓦斯吸附和自振频率测试系统，对含瓦斯煤自振频率特征开展研究，分析瓦斯蚀损时煤体自振频率的“蠕变特征”及可逆性，并利用红外光谱技术探析该 “蚀蠕效应”的微观机制。利用振动试验台，研究振动参数（加速度、频率）对受约束含瓦斯煤受振损伤激发效应的影响规律，分析自振频率随煤体损伤的演变规律，探寻煤体自振频率变化率与损伤能量、程度间的关系。成果有利于完善煤与瓦斯突出的共振诱发机理及预防预测机制。

爆破振动（特别是共振）是煤与瓦斯突出的重要诱发及加剧因素，掌握准确的煤体自振频率及受振损伤激发特征，是确定爆破参数优化目标、进行共振调控的关键。课题开展煤岩自振频率及其影响因素、煤岩静爆振动、甲烷爆燃振动扰动特征等相关研究，研究成果包括：（1）利用敲击法测试原煤试件干燥前后的加速度响应特征，通过其频谱特征分析水分对原煤自振频率的影响规律，随着含水量的增加，煤岩刚度下降，质量增加，阻尼比增加，自振频率有明显下降的趋势；（2）利用静态破碎剂实现煤岩静爆拉伸破坏，实验模拟研究煤岩的静爆致裂过程，分析煤岩静爆致裂过程中微震活动规律（信号幅值、能量、时间及计数等）及其频谱演化特征；（3）探究甲烷-空气预混气体爆燃过程中容器壁的动态响应特征，及内部阻塞率对动态响应特性的影响规律和机理，通过自主搭建甲烷泄爆动态力学响应测试系统，实验研究了甲烷泄爆作用下爆炸容器壁的振动响应特性，以初步探究甲烷爆炸下巷道壁的动态响应特性及其影响机制；（4）为了模拟在矿井瓦斯突发事件及瓦斯爆炸演化过程中的瓦斯浓度在巷道内多维不均匀性，项目设计了可燃气体泄漏扩散过程中非均匀分布及燃爆特性实验系统，并开展了相关燃爆特性实验研究。研究成果有利于完善煤与瓦斯突出的振动诱发机理及调控机制。