构造煤摩擦面与剪切摩擦作用机制研究

Tectonically deformed coal (TDC) and its commonly existed sliding surface, as research subjects, are the main restrictions of coalbed methane (CBM) exploitation and coal mine safety production. The types, deformation sequence, combination of microscopic deformation structures and scale differentiation effect of TDC will be determined according to the analysis of its macro- and microscopic deformation characteristics and structural features. The difference of sliding surface in the development degrees, macro- and microscopic deformation characteristics and morphology features among different types of TDC will be emphatically discussed and classified, then the differences in deformation characteristics, formation symbols, formation conditions and deformation properties of various types of sliding surface can be determined. The formation characteristics of the new microscopic fractures and the deformation characteristics of the new sliding surfaces will be evaluated based on the coal triaxial compression tests, with different strain rate. In combination with the infrared spectra microscope analysis and the constant speed friction test, the dynamic metamorphism of coal will be verified. Based on the above analysis, the main controlling mechanical factors of sliding surface morphology features difference and the stress-strain state of shear friction will be determined. Finally, combined with systematic analysis of deformation characteristics, deformation properties and deformation conditions of TDC, deformation mechanism of TDC will be provided as theoretical basis for the TDC prediction and reservoir evaluation.

以限制煤层气开发和矿井安全生产的构造煤及其中普遍发育的摩擦面为研究对象，通过构造煤宏观和微观变形特征和结构特征的分析，划分出构造煤的类型和变形序列，查明构造煤变形的尺度分异效应和显微复合变形特征。重点探讨不同类型构造煤中摩擦面的发育程度、宏观与微观变形特征及形貌特征的差异性，并进行归类分析，揭示各种类型摩擦面的变形特征、成因标志及所反应的形成条件和变形性质的差异。进行不同应变速率的煤三轴压缩实验，分析显微裂隙的扩展发育特征和新生摩擦面的发育和变形特征，辅以摩擦面显微红外光谱分析，验证动力变质作用的发生；进一步结合煤定速摩擦实验，综合分析摩擦面形貌特征差异的主控力学因素及剪切摩擦作用发生的应力-应变环境，建立摩擦面变形特征与变形条件的对应关系。最后结合构造煤变形特征、变形性质和变形条件的系统分析，完善和查明构造煤的成因机制，为构造煤的预测和煤储层评价提供理论依据。

以限制煤层气开发和矿井安全生产的构造煤及其中普遍发育的摩擦面为研究对象，在构造煤宏观、微观变形及其结构特征与摩擦面特征深入研究的基础上，将构造煤类型系统的划分为碎裂煤、片状煤、碎斑煤、碎粒煤、鳞片煤、揉皱煤和糜棱煤7种类型及19种亚类，并指出了构造煤变形序列具有“多种作用结合、整体错列增长”的演化特征，提出了构造煤显微复合变形构造及尺度分异效应的新观点。首次进行了构造煤摩擦面的变形特征、组合样式和分类研究，将构造煤中常见摩擦面分为：P型、N型、S型、C型、W型和D型共计6大类16种亚类型。揭示了构造煤摩擦面相关发育和穿越效应，表现为随着构造煤变形序列的演化，摩擦面类型依次由N型向S型、C型、P型、W型和D型逐步过渡发育的现象，同时也存在强变形煤体内多种类型摩擦面的发育和变形较弱构造煤类型中强烈变形摩擦面发育的穿越效应。提出了摩擦面的滑移剪裂作用、刻划研磨作用、摩擦釉化作用和碎粒压实作用的力学成因模式。探讨了构造煤中粘土矿物的发育对煤体和摩擦面构造变形程度和变形性质的影响作用，指出粘土矿物发育区域常伴有构造变形增强、变形性质向韧性转变的现象，主要受其力学性质和生烃能力的差异以及产状的综合作用所致。D型摩擦面为富烃高流压下的高应变速率剪切摩擦作用产物，条带状互层发育的粘土矿物则利于揉皱韧性变形的发生和W型摩擦面的形成，而过高粘土矿物含量所引起的高煤体力学强度则常导致构造分异和C型摩擦面的发育。提出了碎裂剪切摩擦作用、劈理剪切摩擦作用、鳞片压剪摩擦作用、弯滑揉皱剪切摩擦作用和高应变速率剪切摩擦作用5种摩擦面成因模式。进一步结合研究区构造演化与构造煤变形特征，提出了10种构造煤发育地质模式，并阐明了其构造成因机制，明确了剪切摩擦作用在煤层变形与构造煤形成过程中的重要意义，为构造煤发育的预测和煤层气可采性评价以及煤与瓦斯突出危险性预测方面均具有重要的科学和实际意义。