【作者】 高峰；

【导师】 周科平；

【作者基本信息】 中南大学 ， 安全技术及工程， 2009， 博士

【摘要】 连续采矿顶板诱导崩落技术是连续采矿技术和诱导崩落技术的有机结合。其中,诱导崩落是区别于传统自然崩落和强制崩落的技术创新。它基于人工扰动诱发岩石力学系统失稳原理,转变地下开采应力致灾思维定式,将岩体中采动应力时空演化诱导成致裂破岩的有利因素,在保证采矿工作面连续推进的同时,实现采空区安全处理和次生灾害的断链控制。传统观点认为,地下岩体工程中复杂应力和应变环境是导致灾害发生的主要条件之一。但是,应力集中或高应力状态下,硬岩的“好凿好爆”和更易致裂破碎的现象启示我们如何充分利用回采扰动与应力集中的能量释放及卸荷作用耦合诱导破裂矿岩。因此,诱导崩落技术在矿体开采和空区处理中具有广泛的应用价值。本文在“十五”、“十一五”国家科技攻关项目基础之上,针对连续采矿顶板诱导崩落机理及次生灾害控制问题开展了深入研究。主要研究内容包括:分析了顶板诱导崩落技术的实施背景及连续采矿与顶板诱导崩落空区处理技术耦合的可行性;基于弹塑性力学,将顶板力学系统简化为平面模型,分析了顶板失稳力学原理,根据格里菲斯双剪强度理论,说明了顶板发生屈服及破坏的条件。根据突变理论,建立扰动诱发顶板失稳的尖点突变数学模型,对临界微扰超前强扰诱发顶板岩石力学系统失稳的机理进行了分析,采用分岔与混沌理论阐述了诱导崩落扰动失稳的非线性本质特征,从岩石力学系统运动角度揭示了顶板诱导崩落的基本原理。采用数值方法和相似材料试验方法对连续采矿顶板诱导崩落过程进行了模拟研究。说明了在特定回采时间和空间效应下超前诱导顶板崩落对于采空区安全控制的意义。重点开展顶板诱导崩落扰动路径下,岩石卸荷特性实验研究。采用MTS815型电液伺服材料试验机对铜坑矿92号矿体顶板灰岩进行了常规三轴试验、峰前和峰后卸荷试验,分析了不同围压卸荷条件下岩石的强度特征、破坏特征,反映了顶板诱导崩落的岩石性质弱化和变形破坏机理。揭示了扰动卸荷与常规加载应力路径下的力学特性差异,并探讨了爆破预裂成缝机理及裂纹萌生、扩展和贯通的力学机制。在连续采矿诱导崩落技术实际工程应用的基础上,采用数字光学前景钻孔电视与数字式全景钻孔摄像系统(DPBCS)对不同扰动时间岩体内节理、裂隙情况进行探测。评价了诱导崩落实施效果,在裂隙统计分析的基础上,引入分形理论,分析了岩体内裂隙分布的分形特征,得出了裂隙演化与岩体宏观时效断裂的相关性。引入灾害链式理论,指出超前诱导空区顶板崩落防止不可预测次生灾害发生的断链减灾模式,初步提出矿山采动致灾链式效应概念,构建了采动灾害链式效应数学模型。并以断链减灾方法对诱导崩落及矿山灾害的控制研究进行了尝试,为工程实践提供一定的参考依据。更多还原

【Abstract】 Technology of continuous mining-induced caving roof is the organic combination of continuous mining technology and induced caving roof technology. Induced caving roof is a technological innovation, which is different from traditional block caving and forced caving substantively. It is based on the principle of rock mechanics system instability induced by artificial disturbance. The thinking formulary of underground mining disaster initiated by stress in rock mass is changed. So the stress and its time-space evolution can be induced to favorable factors used for broken rocks. While ensuring continuous advancing of the mine face, it can realize safe disposal of the mined-out area and chain breaking control. On traditional view, complex stress and strain environment of underground rock engineering is the main factor of development of disaster. However, under the condition of stress concentration or high stress condition, hard rock can be easily drilled and blasted. This phenomenon tells us how to make full use of stress concentration, energy release of stoping disturbance and unloading failure effect to induce rupture of ore rock, which has important significance for safe and efficient mining. Therefore, induced caving roof technology has extensive value in mining and gob handling.Based on the Tenth Five-year and the Eleventh Five-year National Key Project of Scientific and Technical Supporting Programs Funded by Ministry of Science & Technology of China, the mechanism of induced fracture of roof and its secondary disaster control have been deeply studied. The main contents of the study are as follows:Operation background of induced caving roof and the feasibility of coupling continuous mining with mined stope processing in area of induced caving are analyzed. Based on classic elastoplastic theory, instability principle is studied on the basis of plane model, which is simplified mechanical system of roof. The yielding and failure conditions of roof are explained by Griffith’s Theory of twin Shear strength.Cusp catastrophe mathematical model of roof failure induced by disturbance is built based on catastrophe theory to analyze instability mechanism of rock mechanics system of roof induced by effect of micro-disturbance under critical condition and macro-disturbance under near critical condition. The nonlinear character of failure disturbed by inducement dilapidation is reinforced by description using bifurcation and chaotic theory. Basic principle of induced caving roof explained from angle of rock mechanical system motion.By using numerical simulation and similar material simulation, the process of continuous mining-induced caving roof is studied. The results show that advance caving roof in special stoping time and space is important to safety control of gap.The experiment of characters of unloaded rock mass under disturbing condition of caving induced roof is to be mainly studied. By using MTS815 electro-hydraulic servo testing machine, true triaxial, pre-peak and post-peak unloading experiments of roof limestone in Tongkeng No.92 ore-body are conducted, strength character and failure characteristics of rock with different confining pressures unloaded condition are analyzed, and reflect property weakening and deformation failure mechanism of rock with caving induced roof. It reveals that mechanical properties is different between disturbing unloaded and general loaded stress path, and then discussed mechanism of pre-split blasting and mechanical mechanism of crack initiation, extension and transfixion.The digital optical prospects borehole television and digital panoramic borehole camera system (DPBCS) were used to detect rock joint and crack at the different disturbance time after engineering implementation. The effect of induced caving was evaluated objectively. Based on the analysis of crack statistics, by introducing fractal theory to analyze the fractal characteristics of crack distribution inner rock, and obtained the relativity between cracks evolution and macro-aging of rock crack.Using disaster chain theory to indicate the broken chain of disaster reduction mode that leading induced caving of gap roof to prevent the unpredictable secondary disasters, and proposed the concept of mining disturbance hazard chain effect, then built a chain effect of mining disasters mathematical model. Using the broken chain of disaster reduction method used on the research of induced caving and controlling the mine disaster, which provided a certain reference for the engineering practice.更多还原