煤岩固–气耦合细观力学试验装置的研制

RESEARCH AND DEVELOPMENT OF TESTING APPARATUS OF COAL SOLID-GAS COUPLED MESO-MECHANICS

为从细观力学的角度出发研究含瓦斯煤岩变形破坏规律,研制一种煤岩固–气耦合细观力学试验装置,并对装置密封、透明视镜等关键技术难点进行深入分析。该试验装置主要由加载系统、充瓦斯系统、细观观测系统和声发射监测系统4个部分组成。与现有的细观试验装置相比,该装置具有以下特点:可提供单轴、平面应变、三轴(σ2=σ3)三种受力状态;试验测试方法多样化,可进行试验过程中的实时显微图像观测和应力–应变、声发射信号的采集;具有良好的气密性和耐爆性,创造具有瓦斯的试验环境,使煤与瓦斯突出机制的试验研究更加接近矿山实际;装置的结构简单,成本低,系统可靠性高。利用该装置进行瓦斯压力为1.0MPa、围压为1.0MPa(σ2=σ3)下的煤岩细观力学试验,得到煤样受力破坏全过程的表观图像和声发射特征,以此分析试件破坏前后局部区域张拉裂纹的形成和扩展情况。初步的试验结果表明,该试验装置为固–气耦合条件下的相关试验研究提供新的测试手段,具有较大实用价值。

A coal solid-gas coupled meso-mechanical testing apparatus has been developed, which can be used to study the law of deformation and destruction of gas-bearing coal. Some key technical issues, such as sealing method, light transmitting mirror technique, etc., have been further analyzed. The apparatus is comprised of loading system, gas charging system, microscopic observation Compared with the current meso-mechanics apparatus, it system and acoustic emission monitoring system. has the following advantages. Firstly, three types of force state are provided including uniaxial compression, plane strain and triaxial compression（σ2=σ3）. Secondly, several measuring methods are offered, and the real-time observation of the micro-structural images and the collection of stress-strain and acoustic emission signals are realized during experimental process. Thirdly, it is gas-tight and exploding endurable, which makes it similar to actual testing environment. Fourthly, the structure is very simple, low-cost and high reliability. The meso-mechanics experiments have been carried out using this apparatus under gas pressure of 1.0 MPa and confining pressure of 1.0 MPa（σ2=σ3）. And the apparent images and acoustic emission characteristics in failure process of coal specimens have been obtained. The formation process of tension cracks and their propagation in regional areas before and after failure have been analyzed. It is shown that the testing apparatus can provide a new and practical test method for solid-gas coupled experiments.