构造煤摩擦面分子结构演化特征及机理研究

Study on the evolution characteristics and mechanism of molecular structure on friction surfaces in tectonically deformed coals (TDCs)

中文关键词: 构造煤  构造应力  剪切摩擦  摩擦面  煤分子结构中图分类号:TD713文献标志码:A文章编号:1674-7801(2025)02-0227-12

英文关键词: tectonically deformed coal  tectonic stress  shear friction  friction surface  coal molecular structure

中文摘要:

      构造煤摩擦面物理、化学结构变化记录了构造煤形成演化过程，现有研究较少涉及摩擦面分子结构演化的理论研究。为研究不同序列构造煤摩擦面发育特征以及分子结构的演化过程和机制，以宿县矿区祁南矿典型构造煤样品为研究对象，通过宏观观测构造煤摩擦面形貌特征，发现构造煤中主要发育条痕摩擦面和镜面摩擦面 2种类型摩擦面，同时随着剪切摩擦作用增强，构造煤摩擦面逐步由条痕摩擦面向镜面摩擦面演化过渡。原位分子结构测试结果表明，构造煤摩擦面上分子结构演化遵循应力降解—应力松弛—应力重排—应力缩聚的演化过程和模式。随剪切摩擦作用增强，摩擦面上稳定性较差的脂肪侧链及部分含氧官能团优先发生应力降解作用，使得芳香结构的取代基数量减少，同时导致芳香化程度增加，生烃潜能降低。应力降解作用下构造煤摩擦面分子结构活动性增强，促进分子结构的应力重排作用，加之剪切摩擦作用下，摩擦面煤分子结构发生应力缩聚作用，从而促使构造煤摩擦面上芳香度和缩聚程度升高。

英文摘要:

      The physical and chemical structural changes of friction surfaces in TDCs record the formation and evolution process of TDCs, however, existing research rarely involves theoretical studies on the molecular structure evolution of friction surfaces. To investigate the development characteristics of friction surfaces and the evolution process and mechanism of molecular structures in TDC of different sequences, typical TDC samples from the Qinan Mine in the Suxian mining area were selected as the research object. Through macroscopic observation of the mor-phological characteristics of the friction surfaces in TDCs, it was found that the development of streaked friction surfaces and mirror-like friction surfaces two main types of friction surfaces. As the shear friction effect intensifies, the friction surfaces in TDCs gradually evolve from streaked friction surfaces to mirror-like friction surfaces. In-situ molecular structure testing results indicate that molecular structure evolution on the friction surfaces of TDCs follows the process and pattern of stress degradation, stress relaxation, stress rearrangement, and stress polycondensation. With increasing shear friction, the less stable aliphatic side chains and some oxygen-containing functional groups on the friction surfaces undergo stress degradation preferentially, leading to a reduction in the number of substituents on the aromatic structures and a decrease in hydrocarbon generation potential. The stress degradation increases the molecular structure-activity on the friction surfaces of TDCs, promoting stress rearrangement of the molecular structures. Additionally, under shear friction, the molecular structures on the friction surfaces can also undergo stress polycondensation, thereby increasing the aromaticity and polycondensation degree on the friction surfaces of TDCs.