【作者】 郭密文；

【导师】 隋旺华；

【作者基本信息】 中国矿业大学 ， 地质工程， 2010， 博士

【摘要】 矿井溃砂灾害是煤矿建设和生产中的重大地质灾害。化学注浆是解决低渗透性松散层注浆和矿井水砂灾害防治的有效手段之一,对化学浆液在高压封闭条件下的扩散机理进行研究将为化学注浆实践的发展奠定理论基础。本文受国家自然科学基金研究项目“矿井溃砂地质灾害化学注浆治理机制与过程监控”的资助,对高压封闭条件下砂层化学注浆进行模拟试验研究。本文利用自行研制的高压注浆模拟试验设备,完成了九组高压封闭条件下砂层化学注浆模拟试验和一组低压封闭环境下注浆试验。通过(1)分析浆液在固化过程中渗透能力的变化;(2)分析注浆压力—孔隙水压力的变化特点;(3)分析注浆固结体形状特点;(4)对固结体进行解剖观察;(5)采用MATLAB和Photoshop软件对固结体图像进行处理分析;以及(6)与低压环境注浆结果、现场实测数据和他人研究成果进行对比等综合手段,研究浆液的扩散模式和机理。取得的主要成果有:(1)概化建立了第四系深部饱和砂层化学注浆的工程地质模型。(2)详细研究了高压注浆试验模型的实验需求和实现途径,并研制成功了高压注浆模型试验设备专利产品。(3)根据浆液在孔隙介质中渗透能力变化的特点,引入了“絮凝时间”的概念,并将其定义为:从主剂与固化剂混合开始至产生的絮体最大直径达到2.0 mm时为止所需要的时间,该定义对于分析粘时变浆液的渗透能力变化具有实际应用价值。根据分散相颗粒对浆液在孔隙介质中的渗透能力的影响程度,将浆液固化过程划分为四个阶段:凝聚;絮凝;胶凝;固化。(4)分析了高压封闭条件下化学注浆试验的相似准则。根据试验结果,提出了高压封闭环境下饱和孔隙介质中注浆浆液运动的三种扩散模式:球形扩散模式,指形扩散模式和面状扩散模式。(5)提出了在高压封闭条件下饱和孔隙介质中化学注浆的三种浆液扩散机理:“置换推进”机制,“优势路径”机制和“分层富集”机制。(6)建立了高压环境下浆液扩散的宏观过程概念模型,从注浆口至最外缘在空间上分区段阐述了浆液的运动特点。(7)建立了高压环境下浆液扩散的微观过程概念模型,从注浆开始至注浆结束在时间上分时段阐述了浆液的运动特点。更多还原

【Abstract】 Quicksand is a common type of geological hazards in underground coalmines. Chemical grouting is one of the effective methods to prevent coalmines from quicksand hazard by grouting into the low permeable loose soil layers. The investigation of the propagation mechanism of chemical grout injection into porous media under a high pressure and closed environment will provide a theoretical basis for the grouting practice. Supported by National Natural Science Foundation of China, an experimental investigation of chemical grouting into sand under a high pressure and closed environment was carried out in this dissertation.The author has conducted nine scaled tests of chemical grouting under a high pressure and closed environment and one test under a low pressure. The spread model and propagation mechanism of chemical grout in porous media was investigated through a series approaches, which include: (1) analysis of the changes in permeability of the grouts during its curing process; (2) analysis of the changes of the pumping pressure and pore water pressure during grouting; (3) analysis of the characteristics of stabilized shapes; (4) anatomical observation on stabilized sand mass; (5) analysis of images by MATLAB and Photoshop software; and (6) comparison of the results with those from test under a low pressure, with in-situe measurements and the literature. The main achievements are as follows.(1) An engineering geological model for chemical grouting into saturated sand layer in the deep Quaternary System was established.(2) The design of high pressure grouting model was explained in detail, and a patented high-pressure grouting equipment was developed.(3) The concept of the“Flocculation time”was proposed according to the characteristics of the variations of grout infiltration capacity into porous media. The flocculation time was defined as the time interval from the moment the main agent and curing agent mixed until the moment the maximum diameter of the flocs was up to 2.0mm. This definition is useful for analyzing the infiltration capacity changes of time-dependent viscosity grout in practice. Based on the influence of dispersed particles on infiltration capacity of chemical grout in porous media, the grout curing process was divided into four stages: condensation; flocculation; gelling and curing.(4) The similarity for the scaled test of chemical grouting under a high pressure and closed enviromnet was analyzed. The experimental results show that the spread of chemical grout injection in saturated porous media under a high pressure and closed environment was categorized into three patterns. They are a) spherical spread, b) fingering spread and c) planar spread.(5) According to the analysis of experimental results, the propagation mechanism of chemical grouting under high pressure and closed environment into saturated porous medium was summarized into three types, and they are a) mechanism of“replacement to move forward”, b) mechanism of“preferred path”, and c) mechanism of“layering enrichment”.(6) The macro-process and micro-process conceptual model of grout spread under high pressure and closed environment were established, the movement characteristics of grout in space from grout-outlet to exterior margin and during the time from the beginning to the end of grouting were discussed in detail.更多还原