基于声发射技术的采场顶板破断行为试验研究

发布时间：2018-04-20 02:35

本文选题：时变边界系统 + 采场顶板　；参考：《中国矿业大学》2015年博士论文

【摘要】：在煤层开采过程,工作面顶板发生准周期性破断,故顶板属于典型的时变边界结构。由于破断位置事先未知,而且破断后顶板位形的连通性也与初始状态完全不同,故开采过程中顶板破断行为超出了传统固体力学的研究范围。顶板的破断过程伴随着声发射活动,声发射技术是研究采场顶板破断行为的有效手段。由于采矿工程领域中时变边界问题普遍存在,环境保护和矿井灾害防治对时变边界系统的研究提出迫切要求。本文通过物理模拟研究采场顶板的破断过程,并利用声发射技术确定破断面位置和破断时间,深入研究采场顶板的破断规律。通过研究,取得如下创新性成果:(1)通过岩石声发射试验,得到了试验机刚度和加载速率对声发射信号参数影响的规律。(2)在分析采场顶板约束条件、受力条件、边界变化特征和破断过程的基础上,设计了一套岩层破断边界时变声发射试验系统,为研究顶板边界时变破断行为提供了试验手段。(3)利用解除约束的方法实现顶板边界的变化,引入压力变化因子表征顶板底部约束解除的范围。建立了顶板破断位置、破断时间和压力变化因子的关系,得到了煤层原岩应力对破断面形成时间、破断面间距、释放能量的影响规律。(4)通过不同载荷条件下的顶板破断过程的声发射试验,利用声发射图像诊断技术,分析了顶板岩层的破断方式,得到顶板岩层从脆性断裂转换为韧性断裂的规律。(5)将图像诊断技术应用于声发射信号参数分析,提出顶板岩层破断面的声发射图像诊断定位方法。(6)通过顶板岩层的声发射图像诊断定位试验,精确地确定了时变边界岩层的各个破断面区域和破断时间。
[Abstract]:In the process of coal seam mining, the roof of the working face is broken in a quasi-periodic manner, so the roof belongs to the typical time-varying boundary structure. Because the breaking position is unknown in advance and the connectivity of roof configuration after breaking is completely different from the initial state, the roof breaking behavior in mining process is beyond the scope of traditional solid mechanics. The breaking process of roof is accompanied by acoustic emission activity. Acoustic emission technology is an effective means to study roof breaking behavior in stope. Due to the existence of time-varying boundary problems in mining engineering, the study of time-varying boundary system is urgently required by environmental protection and mine disaster prevention. In this paper, the breaking process of stope roof is studied by physical simulation, and the breaking section position and breaking time are determined by acoustic emission technique, and the breakage law of stope roof is deeply studied. Through the research, the following innovative achievement is obtained: 1) through the rock acoustic emission test, the regularity of the influence of the stiffness and loading rate of the testing machine on the acoustic emission signal parameters is obtained. 2) the constraint condition and the force condition of the roof of the stope are analyzed. Based on the characteristics of boundary change and fracture process, a set of acoustic emission test system for rock layer breaking boundary is designed, which provides a test means for studying the time-varying breaking behavior of roof boundary. The method of lifting constraints is used to realize the change of roof boundary. The pressure variation factor is introduced to indicate the range of lifting constraints at the bottom of the roof. The relationship between roof breaking position, breaking time and pressure change factor is established, and the time of formation of original rock stress to breaking section and the interval between broken sections are obtained. Through acoustic emission test of roof breaking process under different loading conditions and using acoustic emission image diagnosis technology, the breaking mode of roof rock is analyzed. The rule of roof rock layer transforming from brittle fracture to ductile fracture is obtained. The image diagnosis technique is applied to the parameter analysis of acoustic emission signal. In this paper, the acoustic emission image diagnosis and localization method of broken section of roof rock layer is put forward. By means of acoustic emission image diagnosis localization test of roof rock layer, each broken section area and breaking time of time-varying boundary rock layer are accurately determined.
【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TD327.2

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