摘要
针对淮南矿区B10煤层以水平层理为主,且层理性较强的特点,通过巴西劈裂及单轴压缩试验,研究煤岩在垂直和平行于层理面方向上的拉、压力学特性。研究结果表明:(1)煤岩垂直和平行于层理面方向抗拉强度均具有明显的离散性,但前者离散程度更大;对比两者均值,前者显然小于后者,各向异性显著。(2)宏观煤岩成分分布的随机性及其物理力学性质的差异是导致煤岩抗拉特性离散性的重要条件;而宏观煤岩成分的条带状分布特点,以及煤岩割理系统分布的方向性,则是决定煤岩力学特性各向异性的内在原因。(3)煤岩垂直与平行于层理面方向单轴压缩轴向应力-应变曲线相比,前者峰前变形特征相似,力学性态稳定,峰后应力跌落迅速,脆性特征明显;后者则峰值前、后各曲线均变形各异,力学性态不稳定。煤样的轴向峰值应变均小于1%,变形特征属脆性破坏。(4)垂直和平行于层理面方向单轴压缩煤样的断口破坏形态分别以剪切和劈裂破坏为主,且2个方向的单轴压缩强度及变形参数均具有明显差异,各向异性特征显著。(5)煤岩垂直和平行于层理面方向单轴压缩特性均具有一定的离散性,但后者离散程度更大。(6)煤岩单轴抗压强度远大于抗拉强度,垂直和平行于层理面方向单轴抗压强度分别为抗拉强度的40.1和14.7倍。
In view of the characteristics of B10 coal layers with significant horizontal bedding in Huainan mining area, tensile and compressive mechanical properties in the directions of vertical and parallel to the coal bedding plane are researched by the Brazilian splitting and uniaxial compression tests. The results show that： （1） Tensile strength in the directions of vertical and parallel to the coal bedding plane are discrete, but the former discrete level is much more. Comparing the mean values in both directions, the former is obviously less than the latter, tensile strength has obvious anisotropy. （2） The random distribution of macroscopic coal composition and its differences on physico-mechanical properties are the important conditions which lead to the discreteness of tensile strength. Moreover, banding distribution characteristics of macroscopic coal components and directivity of coal cleat system are the internal causes to decide the anisotropy of coal mechanical properties. （3） Comparing the axial stress-strain curves in the directions of vertical and parallel to the coal bedding plane under uniaxial compression,the former pre-peak deformation characteristics are similar~ the mechanical properties are stable; the post-peak stress drops quickly and the brittle feature is apparent. However, the latter pre-peak and post-peak deformation characteristics of each curve are different; and mechanical properties are unstable. Meanwhile, the axial peak strains of all coal samples are less than 1%. Thus, the deformation features are in a brittle failure state. （4） Fracture failure pattems of coal samples in the directions of vertical and parallel to the bedding plane are respectively given priority to shear and fracturing failure under uniaxial compression; and the uniaxial compression strength and deformation parameters in both directions are obviously different. In other words, the anisotropy is apparent. （5） The uniaxial compression characteristics in the direction of vertical and parallel to the coal bedding plane are discrete; but the latter discreteness is much more obvious. （6） The uniaxial compressive strength is much greater than the tensile strength, uniaxial compression strength in the directions of vertical and parallel to bedding plane are respectively 40.1 and 14.7 times of tensile strength.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2013年第2期308-316,共9页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(41130742)
国家自然科学基金青年基金项目(41102198)
中国科学院知识创新工程重要方向项目(kzcx2-yw-152)
关键词
采矿工程
煤岩
层理
抗拉强度
单轴压缩试验
垂直
平行
各向异性
mining engineering
coal
bedding
tensile strength
uniaxial compression test
vertical
parallel
anisotropy
