【作者】 程鹏达；

【导师】 王道增；

【作者基本信息】 上海大学 ， 流体力学， 2012， 博士

【摘要】 近年来,随着我国经济快速发展,大量电站、矿井、公路、铁路等重大项目相继建设,其中大部分工程都会涉及穿越富水地层。富水区防渗加固工程由于地层地质结构较为松散、外水压力较大,易突涌水,施工难度很大,风险极高,成为众多工程建设中的控制性工程。富水区一旦发生突涌水事故,将会造成严重的伤亡事故和巨大的经济损失,而且施救难度非常大,甚至还会给运营留下安全隐患。此外地层中的地下水若长期大量排出,不但排水能耗大幅攀升,还将引起众多地质生态灾害。良好的防渗治水加固处理,既可预防突涌水灾害发生,保障施工和运营安全,也可大幅降低抽水能耗,保护地下水资源和当地生态环境。所以,本课题对高压富水区孔隙地层防渗加固工程具有重要的理论和工程应用意义。本文结合高压富水区孔隙地层防渗加固工程难点和纳米新材料研究成果,分析了粘性浆液流动模型,研究了浆液的流变特性及其影响因素,制备了纳米复合注浆浆液,并对纳米复合浆液和速凝纳米复合浆液流变性和结石强度进行理论分析和实验研究,得到了不同纳米颗粒含量浆液和速凝纳米浆液粘度随时间变化规律和不同时段结石强度变化规律。分析了注浆过程中应力场和渗流场的耦合作用,在浆液压力的作用下,多孔介质骨架发生了形变,孔隙率的改变使得流体的渗流通道发生了改变,渗流通道的改变引起了渗透率的变化,从而使得渗流场和应力场之间形成耦合。建立粘性时变性浆液注浆过程的流固耦合数学模型,引入粘性、孔隙率、渗透率的动态参数模型,对粘性时变性浆液注浆过程中的流固耦合物理特性及其对浆液扩散半径的影响进行分析。发现浆液扩散半径可通过分析流速、孔隙率或应变率变化初步确定。同时还进行单孔分段注浆验证试验,然后对开挖后结石直径进行现场测量和土工实验。计算结果比传统Maag公式更接近实验结果,说明了注浆过程中考虑耦合的必要性和该数学模型在孔隙地层注浆分析中的合理性。针对高压富水区孔隙地层实际工程地质条件,提出纳米复合注浆浆液与排水式注浆工艺相结合的施工方案。建立适合孔隙地层注浆过程的流固耦合数学模型,对粘性时变性浆液的排水式注浆和单孔注浆扩散进行数值模拟,并分析了两种注浆方式对注浆扩散半径的影响。参考数值计算结果,在西南某煤矿工程中设计排水式注浆防渗治水施工方案,然后进行钻心取样和压水实验。测量结果表明,采用该技术方案后注浆孔周围的外水压力大幅降低,注浆结石强度和防渗能力都有了大幅提高,提高了注浆效率,降低了注浆能耗,为高压富水区孔隙地层防渗加固施工提供了新思路,对预防突涌水灾害发生,降低泥石流、滑坡等灾害发生概率和降低能耗实现节能减排,保护宝贵的地下水资源均有重要意义。更多还原

【Abstract】 With big economic growth in China, major infrastructure construction projects have to deal with the stratum with abundant water. Because the loose geological structure and the high external water pressure, anti-seepage projects are often companied with great difficulty and high risks, which makes it the controlling part of projects. Once water gushing burst happened, serious casualties and huge economic losses will be caused, while the rescue is very hard, and the hidden security risks might be left for later operation. In addition, if the underground water kept draining for a long time, it will not only consume energy for pumping, but also incite geological and ecological disasters. For above reasons, the research on anti-seepage treatment in high pressure and rich water area is endowed theoretical and pragmatic significance.In this dissertation, the difficulties of anti-seepage treatment in high pressure and rich water area, as well as the characteristics of Nano-materials are taken into consideration for analyzing the viscous flow models of grout, the rheological properties of grout and its influence factors. Based on the analysis of the experiments concerning Nano-composite grout, rapid solidification Nano-composite grout, and the strength of consolidation, it concluded that the rheological properties of grout and the strength of consolidation changed with time and the percent of Nano materials.Stress field and seepage field coupling are analyzed in the process of grouting. It generated that the grouting pressure leads to porous skeleton changed, and the changes of porosity lead to the change of permeability, in this case, the coupling of stress field and seepage field should be considered during grouting. The principle of effective stress for porous medium is applied to analysis the fluid-structure coupling in the process of grouting, meanwhile, the coupling physical variables, dynamic models of porosity, permeability and viscosity are introduced. The diffusion radius thus can be defined by the foundational porosity and grout velocity. The single-hole sub-grouting verification is experimented for the diameter measurements and geotechnical tests on the on-site excavation stone. It shows that the calculation results are approaching more to the experiment results than to the traditional Maag formula. Therefore, the necessity of coupling consideration and the rationality of the application of fluid-structure coupling model to seepage field are verified.The construction program that combined the Nano-composite grout of controllable solidification and the grouting technology of filtering water is proposed, under the consideration about the geological conditions of high pressure and rich water area. The coupling mathematical model of grouting in porous medium is established, and the diffusion radius defined by the porosity and grout velocity is analyzed. The distribution of holes is designed according to the diffusion radius of grout in the sample coal mine engineering project in southwest China. Then, the permeability and the strength test were designed to verify grout effect. The final result shows that the permeability and the strength are greatly improved; the efficiency is also enhanced, while the energy consumption of grouting is reduced. This dissertation provides a new thinking for the anti-seepage treatment in high pressure and rich water area. It will be useful to prevent the gushing water disaster, to reduce the energy consumption, and to protect the under-ground water resources.更多还原