奥陶系灰岩上部岩溶裂隙注浆加固作用机理研究

The exploitation of deep coal seams in North China's coalfields is seriously threatened by water inrush from Ordovician limestone karst water. Traditionally, drainage depressurization method and grouting reinforcement of thin limestone are adopted to prevent water inrush from coal seam floor. However, it does not turn out to be successful for the exploitation of deep coal seams. Preventing water inrush from Ordovician limestone water with grouting reinforcement of Ordovician top is prevalent recently; nevertheless, further study on mechanism of the theory is imperative. The methods of laboratory test, numerical simulation, field practice and theory analysis are used to carry out the research. Data of macroscopic analysis and microcosmic test are analyzed by mathematical statistics method to find out the main combination mode of the limestone karst fissure. The microcosmic characteristic of the interface of rock-rock, rock- slurry, and the macroscopic mechanical strengthening rule of the grouted rock are studied. Then the quantitative relations between mechanical property of grouted rock and factors such as fissure, underground water pressure, grouting parameters are analyzed by grey theory to select the controlling factors. Through studying the effect of the rock- slurry cementation interface on rock failure, the structure effect of grouted reinforcement on rock failure is revealed and the mechanical mechanism of grouting reinforcement is illustrated. The seepage-stress test and numerical simulation are adopted to analyze dynamic changing characteristics and destabilization destruction rules of grouting reinforcement rock under the circumstance of mining stress field and confined seepage field to reveal the controlling effect from relevant factors on stabilization of grouting reinforcement rock, which provides Ordovician grouting reinforcement theory essential research achievement.

受奥灰岩溶水威胁的华北型煤田深部煤层开采工作面，在传统疏水降压及薄层灰岩注浆改造防治底板突水技术手段效果不明显时，采用对奥灰上部注浆加固防治高承压水突出已成为防治水技术发展的趋势，但其相应的注浆加固机理亟需深入研究。拟采用室内试验、数值模拟、现场实践、理论分析等途径开展研究。基于宏观分析、微观测试，利用数理统计方法确定岩溶裂隙主要组合模式；研究浆-岩界面微观特征及注浆加固体宏观力学强化规律，基于灰色理论，建立裂隙、地下水压、注浆参量与其力学性能的量化关系，揭示注浆加固强化力学性能的主控因素，探究浆-岩界面对注浆加固体在破坏过程中的控制作用，揭示注浆加固体破坏的结构效应，阐明注浆加固力学机理。基于应力-渗流耦合试验、数值模拟手段，分析开采应力场与承压渗流场作用下的注浆加固体采动效应及破裂失稳规律，揭示相关条件对注浆加固岩体稳定性的控制作用，为奥灰注浆加固理论的建立和发展提供基础研究成果。

受奥灰岩溶水威胁的华北型煤田深部煤层开采工作面，在传统疏水降压及薄层灰岩注浆改造防治底板突水技术手段效果不明显时，采用对奥灰上部注浆加固防治高承压水突出已成为防治水技术发展的趋势，但其相应的注浆加固机理亟需深入研究。本项目采用室内试验、数值模拟、现场实践、理论分析等途径开展了研究。根据肥城煤田奥陶系灰岩上部岩溶裂隙体的特殊性，采用微观与宏观相结合的研究方法，揭示了奥灰上部岩溶-裂隙发育特征及组合模式，确定了奥灰岩溶裂隙垂向发育规律，提出了奥灰突水危险性评价方法，基于此方法确定奥灰上部注浆层位及注浆区域。提出了一种可变角度单裂隙标准岩石试样预制方法，形成了一套可变隙宽及角度的预制裂隙标准岩石试样注浆试验系统；分析了不同注浆参量下浆液结石体的强度特征，建立了浆液结石体强度与各指标间的定量关系；构建了考虑粘土-水泥浆液粘度时空变化的裂隙岩体注浆扩散控制方程并进行了数模模拟，研究了单一裂隙注浆扩散机理；开展了应力-渗流耦合作用下，单裂隙注浆加固体的破坏模拟，揭示奥灰岩上部岩溶裂隙注浆加固对底板破坏的控制作用；分析了奥灰上部注浆加固前、后的采动响应特征，揭示注浆加固对奥灰突水防治的作用。最后，选取注浆方法、注浆工序、注浆材料、浆液比重、注浆压力、注浆孔布设、注浆总量、涌水量分布、涌水量对比及注浆量对比作为注浆效果评价指标，构建了基于 Fuzzy-AHP 的评判模型实现了奥灰注浆效果的评价。本项目研究成果为奥灰注浆加固理论研究及工程实践提供了有意义的指导。