基于固气耦合的煤岩-瓦斯二相介质相似材料及其力学特性

Similar Materials and Mechanical Properties of Coal-Gas Two-phase Media Based on Solid–Gas Coupling

含瓦斯煤是具有多孔特性和固气耦合特性的二相介质复合材料,为了精准模拟含瓦斯煤的物理力学属性,基于相似准则和主控参数相似比尺,进行了80余组材料配比试验和力学参数试验,研制了煤岩−瓦斯二相介质相似材料。对比了相似材料和原煤的相似性,并基于新材料进行了3维煤与瓦斯突出相似模拟试验。主要试验结果如下:1)以煤粉和腐殖酸钠水溶液为骨料和胶结剂配制的煤岩相似材料的弹塑性参数与原煤相似,通过调节材料配比,可以配制不同弹塑性参数的相似材料。相似材料的吸附性与原煤也具有一致性;2)CO_(2)和N_(2)二元混合气体的膨胀能介于CO_(2)和N_(2)之间,气体膨胀能比例系数与CO_(2)体积分数呈二次函数关系,CO_(2)体积分数为45%的混合气体的膨胀能与CH4的膨胀能一致;CO_(2)和N_(2)二元混合气体可作为CH_(4)相似气体,且比CH_(4)安全性高;3)研制的煤岩−瓦斯二相介质相似材料与含瓦斯原煤的物理力学参数均具有高度相似性,实现了固气耦合特性模拟;4)3维物理模拟试验再现了石门揭煤引发煤与瓦斯突出现象,得到与现场接近的突出孔洞形态和突出粉煤质量,验证了相似材料的合理性,也为进一步研究煤与瓦斯突出规律,监测突出前兆信息提供了科学手段。

Gas-containing coal is a two-phase dielectric composite material with porous characteristics and solid-gas coupling characteristics.In order to accurately simulate the physical and mechanical properties of gas-containing coal,based on similarity criteria and similarity scales of main control parameters,with more than 80 sets of material matching tests and mechanical parameter tests,a similar material for coal-gas twophase medium was developed.The similarity between similar materials and raw coal was compared,and based on the new material,a three-dimensional simulation test of coal and gas outburst was performed.The main conclusions were as follows.1)The elastoplastic parameters and adsorption parameters of new material prepared by pulverized coal and sodium humate aqueous solution as aggregate and binder is similar to raw coal.Similar materials with different elastic-plastic parameters can be prepared by adjusting the material ratio.The adsorption of similar materials is consistent with that of raw coal.2)The expansion energy of the binary mixture of CO_(2) and N_(2) is between CO_(2) and N_(2).The proportional coefficient of expansion energy and CO_(2) volume fraction are quadratic functions.The expansion energy of the mixture with 45% CO_(2) volume fraction is consistent with that of CH_(4).The binary mixture of CO_(2) and N_(2) can be used as similar gas to CH_(4),and it is safer than CH_(4).3)The new material is highly similar to the physical and mechanical parameters of raw coal containing gas,which realizes the simulation of gas-solid coupling characteristics.4)A three-dimensional physical simulation experiment reproduces the phenomenon of outburst caused by uncovering coal,and the morphology of outburst holes and the quality of outburst pulverized coal that are close to the field are obtained,which verifies the rationality of similar materials,and also provides a scientific means for further study of the law of outburst and monitoring the precursor information of outburst.