【作者】 钱自卫；

【导师】 曹丽文；

【作者基本信息】 中国矿业大学 ， 地质资源与地质工程， 2014， 博士

【摘要】 鄂尔多斯盆地是我国煤炭能源重点开发区，建井过程的水害问题普遍且突出，不但影响施工质量、延误进度、增加成本，甚至酿成严重工程事故。区内煤矿建井水害集中于洛河、直罗、下石盒子三组区域性富水层段，属微裂隙-孔隙型双重介质，揭露时呈孔隙性渗漏，水量大且稳定，是典型的弱渗富水型砂岩含水层。注浆是目前西部矿区治理弱渗富水砂岩水害较普遍采用的技术方法，已有的工程实践表明，常规水泥注浆方法治理此类砂岩水害因其可注性差而不适用，而化学注浆尚有诸多技术问题有待解决，其中最突出的是充填率及减渗效果偏低的问题。针对目前西部矿区弱渗富水砂岩含水层建井水害注浆防治存在的问题，本论文选择鄂尔多斯盆地建井水害严重且水害层段不同的几个矿井采集岩样，采用扫描电镜、物性指标测试等手段进行了砂岩的结构特征研究。在此基础上，通过模型试验和理论分析，系统研究了孔隙性砂岩的渗透通道条件、浆液的可注性、充填效果及其主要影响因素，揭示了化学浆液在砂岩孔隙中的渗透扩散规律、充填特点及减渗机理，为化学注浆材料性能改良、提高注浆防渗效果提供了基础依据。获得的主要认识如下。（1）对洛河、直罗、下石盒子三组砂岩分层取样进行的性状研究发现：三组砂岩具有相近的微、细观结构条件，物理、力学性质显现有共性特征，主要表现为颗粒级配不良、胶结性差、强度偏低、孔隙连通性好、孔隙率高。（2）孔隙性砂岩的微观渗流特征研究发现：砂岩的渗流孔道虽“四通八达”，但流体的渗流受到孔道特征的制约，仅在部分孔道渗流相对活跃，汇流及分流现象交替产生，且相对活跃的孔道中流体运动方向及通道尺度处于动态变化。（3）通过宏观、细观模拟试验及理论分析，探究了不同类型浆液对于孔隙砂岩的可注性差异及内在机制，研究发现：溶液型化学浆液在孔隙砂岩中的可注性主要受制于渗流通道的结构形态和浆液性能，由于化学浆液粘度较大，孔隙砂岩渗流通道微细，化学浆液在孔隙砂岩中虽具有可注性，但需要的注浆压力较大；水泥类颗粒悬浮型浆液可注性极差，其主要原因是浆液在渗流孔道的变径、变向处渗透扩散时的渗透阻力过大，浆液在孔道中受阻的机理为“相对减速集聚”。（4）依据砂岩孔道渗流特征构建了孔隙砂岩二维渗透模型单元，利用层流均匀流理论结合孔隙砂岩化学注浆模型试验结果，解释了混相、非混相注浆浆液在孔隙中的扩散规律及减渗机理，研究发现：非混相注浆浆液在孔道中呈类活塞式驱替流动，混相注浆浆液在孔道中流动的过程本质为水携带颗粒在孔道中混合运动；化学注浆后减渗率偏低的主要原因是已注入主渗孔道中浆液发生位置移动及浆液存在固结收缩性。（5）基于浆液扩散机理的研究成果，推导了可实现注浆扩散半径、注浆压力、注浆泵量、注浆持续时间等多因素计算分析的浆液柱形扩散理论模型，研究成果在梅花井煤矿副立井过直罗组下段砂岩含水层化学注浆的治理中得到有效检验。更多还原

【Abstract】 Construction quality, coal production and coal mine workers’ safety have been deeply threatened by coal mine well construction water damages which always exist in the sandstone of Luohe Formation, the lower of Zhiluo Formation and Xiashihezi Formation in the Western and South margin of Ordos Basin nowadays. The aquifers, as typical poor seepage aquifers, often come from micro-cracks and pores dual media water that shows porous seepage and high flow rates.The water damages always be governed by cement grouting that has been proved to be non-suitable in this area due to some problems, i.e., the low groutability and unsatisfactory reduced permeability. Likewise, chemical slurry grouting also has lots of defects that low filled rate and reduced permeability rate are outstanding.Through comprehensive study of model experiments and theoretical analysis, the seepage channel of porous sandstone, slurries’ groutability and filled effect, as well as their main factors are analyzed, on the basis of rock sampled from several coal mines and structural characteristics of sandstone analysis by SEM and physical index test. Through the study, conclusions can be drawn as follows:(1) Rock were sampled from Luohe Formation, Zhiluo Formation and Xiashihezi Formation that have similar micro and meso structural characteristics, physical and mechanical properties, which show bad grain composition, strong water yield property, low strength, Good pore connectivity and high permeability.(2) From the micro-seepage characteristic analysis of porous sandstone, the result shows that the seepage channels of sandstone are extending in all directions, while still be influenced by seepage channels’characteristic, and only parts of them are active. Converge and by pass happen in turn, and the fluid direction and channel are being changing all the time.(3) The different groutabilty and internal mechanism of slurries are studied using macro and meso model experiments and theoretical analysis. The study shows that the groutabilty of solution chemical slurry is mainly affected by its properties and morphology of seepage channel. The groutabilty of chemical slurry is low due to its high viscosity and tiny seepage channel. Also, particles suspended grouting materials whose disruption mechanism shows “decelerate and gather” is lower due to the resistance of seepage is high in the diameter and direction changing positions.(4) Dimensional seepage unit of porous sandstone was built on the base of water seepage behavior of sandstone. The slurry diffusion and reduced permeability mechanism of miscible and immiscible were studied by the synthesized analysis of uniform laminar flow theory and chemical slurry grouting experimental result. The results show that immiscible slurry flows as piston driven flow in the porous channel. But the flow essence of miscible slurry may be considered as the water flow along with grains. The low reduced permeability after chemical slurry grouting may mainly caused by the changed position of slurry that has been grouted and the systole of slurry.(5) Slurry cylindrical diffusion theoretical model was deduced from the slurry diffusion mechanism. The grouting diffusion radius, grouting pressure, grouting flow rate and grouting lasting can be calculated by this model. The conclusions have been tested and verified effectively, during the chemical slurry grouting of lower sandstone aquifer of Zhiluo formation in the vice shaft of Meihua Coal Mine.更多还原