孔隙砂岩化学注浆浆液渗透扩散机理

发布时间：2018-06-21 01:56

本文选题：孔隙砂岩含水层 + 孔隙结构　；参考：《中国矿业大学》2014年博士论文

【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。
[Abstract]:Ordos basin is the key development zone of China ' s coal energy , and the problem of water pollution in the well - building process is common and prominent , which not only affects the construction quality , delays the progress , increases the cost , or even makes a serious engineering accident .

Grouting is one of the most commonly used techniques in the treatment of weak - permeability and water - rich sandstone in the western mining area . The existing engineering practice shows that the conventional cement grouting method is not applicable because of its poor injectability , and the chemical grouting has many technical problems to be solved , among which the most prominent is the problem of low filling rate and low permeability .

In view of the problems existing in the prevention and control of water damage in the water - bearing stratum in the weak - seepage water - bearing sandstone in the western mining area , the paper selects several mine - collection rocks which are serious and different from the water - damage layer in the Erdos basin . On the basis of this , the permeability channel conditions , the filling characteristics and the infiltration mechanism of the porous sandstone are studied by means of model tests and theoretical analysis . The permeability diffusion law , the filling characteristics and the infiltration mechanism of the chemical grout in the pore of the sandstone are studied , and the basis for improving the performance of the chemical grouting material and improving the anti - seepage effect of the grouting material are provided .

( 1 ) It is found that three groups of sandstone have similar micro - and meso - structural conditions , physical and mechanical properties show common characteristics , which mainly manifest as poor particle size distribution , poor cementation , low strength , good pore connectivity and high porosity .

( 2 ) The microscopic percolation characteristics of the porous sandstone show that the percolation pore channel of sandstone is " four to eight " , but the seepage of fluid is restricted by the pore channel characteristics , and only in part of the pore channel seepage is relatively active , the confluence and the diversion phenomenon are alternately generated , and the direction of fluid movement and the channel scale in the relatively active pore channel are dynamically changing .

( 3 ) Through macroscopic , microscopic simulation test and theoretical analysis , the injectability difference and internal mechanism of different types of slurries for pore sandstone are explored . It is found that the injectability of solution type chemical grout in the pore sandstone is mainly influenced by the structure and slurry properties of the seepage channel , because the chemical grout has a large viscosity , the pore sandstone seepage channel is fine , the chemical grout has the injectability in the pore sandstone , but the grouting pressure is larger ;
The main reason is that the permeability resistance of the slurry in the channel is too large , and the mechanism of the slurry blockage in the pore channel is " relative deceleration gathering " .

( 4 ) Based on the percolation characteristics of sandstone pore channel , a two - dimensional permeability model unit of pore sandstone is constructed , and the diffusion law of mixed phase and non - miscible grouting slurry in pores is explained by using the theory of laminar flow uniform flow and chemical grouting model test results . It is found that the non - miscible grouting slurry is in the form of piston - like displacement in the pore channel , and the process of the mixed - phase grouting slurry in the pore channel is essentially water - carrying particles to mix and move in the pore channel ;
The main reason for low permeability after chemical grouting is the movement of the slurry in the main infiltration channel and the consolidation shrinkage of the slurry .

( 5 ) Based on the research results of slurry diffusion mechanism , a theoretical model of slurry cylindrical diffusion is derived which can realize multi - factor calculation and analysis of grouting diffusion radius , grouting pressure , grouting pump quantity and grouting duration .
【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TD745

【参考文献】