深井围岩微裂隙渗流特性及扩缝注浆堵水机理研究

In our country, the water seepage from thousand deep mine's shaft which brings grouting difficulty is mainly composed of the seeping water from the micro-fractures surface of the deep sedimentary sandstone. The microcracks structure shows such favourable water permeablity under deep mine's high water pressure that weak superfine cement and chemical grout can be injected into. Engineering practice in coal mines grouting has proved that the application of superfine cement in expanded micro-fracture's grouting technology is a feasible way to solve the water plugging problem. Considering the less insightful study of tests and experiments in sandstone micro-fracture's expanding and grouting mechanism, the value of parameters (which is mainly refered to the grouting pressure) in grouting process are mostly selected empirically, thereby influences the grouting reliability grouting and water plugging effect. This project concentrates on a research of micro-fracture's seepage characteristic and expanded fracture's grouting and water plugging mechanism of the surrounding rock in deep mines, establishes a comprehensive seepage coupled equation between water seepage flow from micro-fractures in typical transversely isotropic sandstone and influencing factors, reveals the diffusion mechanism and seeping law of superfine cement grout in rock micro-fractures, sets up a reasonable expanded fractures' grouting mechanical model as well as the rational basis of micro-fracture's expanding effect. Moreover, this project also promotes an effective parameter computing method in the process of expanded fracture's grouting that effectively ceases water seepage on micro-fracture surface of deep mines, which offers great academic significance as well as engineering practical value and wide application prospect.

我国煤矿千米深井井筒深部难以注浆封堵的渗水，主要来自深部沉积砂岩微裂隙面渗水。该微裂隙结构在深井高水压下具有良好的透水性，但超细水泥浆液乃至化学浆液的可注性极差。煤矿注浆工程实践证明，超细水泥岩体微裂隙扩缝注浆堵水技术，是解决深井微裂隙堵水难题的可行途径。由于目前对砂岩微裂隙扩缝注浆堵水机理的试验和理论研究不够深入，其注浆工艺参数（主要是注浆压力）的确定，在很大程度上依靠经验类比，从而影响了注浆堵水效果的可靠性。本课题开展深井围岩微裂隙渗流特性及超细水泥扩缝注浆堵水机理研究，建立典型横观同性砂岩微裂隙渗流量与影响因素的综合渗流耦合方程，揭示超细水泥浆液在岩体微裂隙的扩散机理和渗流规律，建立扩缝注浆力学模型和微裂隙扩缝效应的合理判据，进而提出有效封堵深井微裂隙面渗水的扩缝注浆工艺参数计算方法，不仅具有重要的学术意义和工程实践价值，还具有广阔的工程应用前景。

随着地下工程建设深度的增加，地应力增大、涌水量加大等深部复杂地质环境愈加显著。煤矿千米深井井筒深部难以注浆封堵的渗水，主要来自深部沉积砂岩微裂隙面渗水。针对其中的关键问题，以深井砂岩微裂隙为研究对象，研究了不同类型深井砂岩的物理与力学特性，研制了微裂隙砂岩相似模型并讨论了其损伤机制，提出了微裂隙三维粗糙度的表征方法，并构建了微裂隙粗糙度指标JRI，揭示了粗糙度因素作用下的微裂隙渗流规律以及微裂隙扩缝增量随法向应力、注水压力的变化规律。.（1）通过光学显微镜和扫描电镜分析了砂岩吸水前后的微观结构。基于砂岩岩样单轴与三轴试验，获得了其应力-应变曲线，并对粗砂岩、中砂岩、细砂岩饱水后单轴抗压强度进行测试，获得了其软化系数，从宏细观角度揭示了深井砂岩基本物理力学特性。.（2）利用JAW-600岩石应力-渗流耦合试验系统开展水力扩缝相似模型试验，借助高敏度光纤光栅传感器及后期处理，获得沿水流路径不同位置试件测点所受到的竖向水压力及水压对微裂隙引起的扩缝增量。.（3）通过正交试验方法设计了骨料占固体物质的比例、骨料成分之比、胶结物成分之比及掺水率四种影响因素，每种影响因素建立三个水平制备了243块微裂隙砂岩相似材料试样，对试样进行了单轴、三轴压缩试验并测试了其吸水率。结合深井砂岩的基本特征，确定了相似材料的最佳配比，建立了其损伤本构方程。.（4）基于微裂隙砂岩相似模型，对微裂隙粗糙度的几何特征进行描述，在此基础上提出了表征粗糙度的新方法，并利用Python编程语言开发了微裂隙三维粗糙度表征程序，揭示了粗糙度参数在各向异性、尺寸效应、间距效应单因素及双因素作用下的演化规律。提出了微裂隙粗糙度指标JRI，构建了JRI与三维粗糙度系数JRC之间的关系表达式。.（5）自主设计研发了微裂隙三轴应力渗流机理模型试验系统，开展了微裂隙砂岩相似模型渗流试验，对渗流过程中裂隙表面的变形及渗流特性展开研究。采用COMSOL软件对应力作用下微裂隙岩体的渗流规律进行模拟，讨论了粗糙度因素作用下微裂隙的渗流特征。