煤破碎过程中表面结构演化与力学特性关系
发布时间：2019-06-02 03:05
【摘要】：利用电子万能试验机对四种典型块煤开展单轴压缩破坏实验,研究其应力应变及破坏形式等力学特性.利用高速摄像仪拍摄煤块表面细观结构图像,并计算分形维数以定量描述煤块在单轴压力载荷下表面细观结构,最终建立应力与表面分形维数的关系.结果表明:煤表面和内部存在大量孔隙、裂隙等缺陷以及其具有的不均匀性,导致其单轴压缩实验力学特性存在各向异性特征,破坏形式主要为沿纵向主裂隙的劈裂破坏;同种煤的最大和最小的应力强度值相差很大,不同煤种的力学参数也有整体的差异性.通过定义相对分形维数和相对应力强度发现单轴压应力与表面分形维数呈现非线性增长关系.
[Abstract]:The uniaxial compression failure experiments of four typical lump coals were carried out by using electronic universal testing machine, and their mechanical properties such as stress, strain and failure form were studied. The surface meso-structure image of coal block is taken by high-speed camera, and the fractal dimension is calculated to quantitatively describe the surface meso-structure of coal block under uniaxial pressure load. finally, the relationship between stress and surface fractal dimension is established. The results show that there are a large number of pores, cracks and their inhomogeneity on the surface and interior of coal, which leads to the anisotropy of the mechanical properties of the uniaxial compression experiment, and the failure form is mainly the split failure along the longitudinal main fracture. The maximum and minimum stress intensity values of the same coal are very different, and the mechanical parameters of different coal types are also different as a whole. By defining the relative fractal dimension and the relative stress intensity, it is found that the uniaxial compressive stress has a nonlinear growth relationship with the surface fractal dimension.
【作者单位】： 华中科技大学煤燃烧国家重点实验室;
【基金】：国家自然科学基金资助项目(51576072)
【分类号】：TD31
[Abstract]:The uniaxial compression failure experiments of four typical lump coals were carried out by using electronic universal testing machine, and their mechanical properties such as stress, strain and failure form were studied. The surface meso-structure image of coal block is taken by high-speed camera, and the fractal dimension is calculated to quantitatively describe the surface meso-structure of coal block under uniaxial pressure load. finally, the relationship between stress and surface fractal dimension is established. The results show that there are a large number of pores, cracks and their inhomogeneity on the surface and interior of coal, which leads to the anisotropy of the mechanical properties of the uniaxial compression experiment, and the failure form is mainly the split failure along the longitudinal main fracture. The maximum and minimum stress intensity values of the same coal are very different, and the mechanical parameters of different coal types are also different as a whole. By defining the relative fractal dimension and the relative stress intensity, it is found that the uniaxial compressive stress has a nonlinear growth relationship with the surface fractal dimension.
【作者单位】： 华中科技大学煤燃烧国家重点实验室;
【基金】：国家自然科学基金资助项目(51576072)
【分类号】：TD31
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