煤矿充填矸石细观组构演化影响应力波传播机制研究

Compactness of backfilling material in gob is the key influence factor for backfilling effect to backfill gob, and meso-fabric characteristics of gangue backfilling is the internal cause for its compactness. The geophysical prospecting is one useful method to get the compactness, mesoscopic fabric data, but the lack of mechanical response of stress waves under compactness and meso-fabric characteristics of gangue backfilling limits its development. Aimed at the problem, some correlative issues in this area are studied. Different from former study, three-dimensional figure of gangue backfilling particle swarm could be drawn the scanned data by CT scanning and graph processing technique, meso-fabric characteristics of gangue backfilling, and the quantitative relation of compactness and mesoscopic fabric of gangue backfilling will be gotten by analyzing the picture. After that, the influence mechanism of compactness and its change on propagation parameters of stress waves could be gotten by autonomous design stress wave detection system, the key factor affecting propagation parameters of stress waves could be decided. And the quantitative description method for the relationship among compactness, mesoscopic fabric and stress wave propagation property is generalized. Base on the data and analysis, the matical model for stress waves and mesoscopic fabric of gangue backfilling will be developed. The results of this proposed research could provide basic theoretical references and data for geophysical prospecting method to obtain compactness and meso-fabric and characteristics of gangue backfilling, which will contribute to further study of the mechanism between gangue backfilling and surrounding rock in mined area.

采空区充填材料压实度是影响矸石充填采煤效果的核心因素，而矸石颗粒细观组构演化是决定充填材料压实度的内在原因。震动物探是研究采空区充填矸石压实度及其细观组构的潜在有效手段，目前制约其应用的最大瓶颈问题是未掌握应力波对充填矸石压实度、细观组构的力学响应机制。围绕该问题开展本项目研究：区别于传统研究方法，本项目利用工业CT和数字图像处理技术获取压实过程中矸石颗粒形态、孔隙分布数据并进行三维重构，统计归纳矸石颗粒体系细观组构演化特征；借助自主设计的应力波检测系统研究压实度及变化对应力波传播的影响规律，确定影响应力波传播的主控因子；得到充填矸石压实度、细观组构及应力波传播特性三者之间的关系及定量表征方法，建立矸石细观组构及其变化影响应力波传播的数学模型。研究成果可为震动物探分析采空区充填矸石压实度及其细观组构特征提供重要数据基础和分析模型，有利于推进对采空区充填体与围岩耦合作用机理的深入研究。

震动物探是研究煤矿采空区充填矸石压实度及其细观组构的潜在有效手段，为了探明应力波对充填矸石压实度、细观组构的力学响应机制，特开展了本研究。三年的研究中，6种典型充填矸石样品被选取测试，同时对充填矸石压缩变形的环境条件（主要是温度和湿度）进行了分析，确定了相应的实验分析条件。利用工业CT和数字图像处理技术获取压实过程中矸石颗粒群的形态、孔隙分布数据并进行了三维数据重构，建成了相应的数据库。给出了变形过程中的煤矿充填矸石颗粒体系细观组构演化特征的数学表达公式；确定纵波的波速与振幅、衰减系数作为实验中应力波的表征参量，并构建了纵波检测系统研究压实度及变化对纵波传播的影响，探明了相应规律及其主控因子（颗粒的平均粒度、孔隙度等因素）；得到煤矿用采空区充填矸石压实度、细观组构及纵波传播特性三者之间的定量表征公式，建立矸石细观组构及其变化影响应力波传播数学模型，探明了温度、湿度对充填矸石中纵波传播特性的影响机制，同时研究了超声波与应力波在充填矸石颗粒群中传播的异同点。本研究成果为震动物探分析采空区充填矸石压实度及其细观组构群体特征提供重要数据基础和分析模型，进一步丰富了煤矿采空区充填质量评价体系。