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基于渗滤效应的水泥浆液多孔介质注浆机理及其工程应用
Grouting Mechanism Based on Filtration in Porous Media with Cement Grout and Its Engineering Application
【作者】 韩伟伟;
【导师】 李术才;
【作者基本信息】 山东大学 , 岩土工程, 2014, 博士
【摘要】 注浆技术是岩土工程中一门专业性很强的学术分支,通过注浆材料的充填和胶结作用实现对受注地层的加固和堵水目的,改善其水文地质和工程地质条件,广泛应用于隧道、矿山、水电站等地下工程的特殊地质灾害治理,并取得了良好的治理效果。伴随着注浆技术的广泛应用,注浆理论、施工技术和注浆材料的研究和应用迅速发展,注浆材料的种类日趋多样化,性能也千差万别。其中水泥类浆液是指以水泥为主体的注浆材料,主要包括普通水泥浆液、水泥-水玻璃浆液和水泥基高聚物改性浆液等,由于价格低廉、环保无毒等优点仍然被广泛采用。普通水泥浆液,属于颗粒型浆液,本文针对水泥浆液多孔介质渗透研究较少的渗滤效应展开研究,主要研究其在渗透扩散过程中的深层渗滤(deep bed filtration)现象针对水泥类浆液首先分析了水泥浆液在多孔介质中的可注性,重点分析了水泥浆液颗粒的表层渗滤现象和介质内部深层渗滤现象。开展了浆液颗粒表层渗滤试验,研究了多孔介质孔隙直径、浆液水灰比和注浆压力三个因素对水泥浆液的表层渗滤的影响,根据试验结果,通过回归分析得到了恒压注浆时注浆量与多孔介质孔隙直径、浆液浓度和注浆压力之间的函数关系;选取混合粒径的砂样开展了一维长柱型渗透试验,研究了考虑深层渗滤效应时注浆过程中的渗流压力的时变规律,分析了深层渗滤效应对注浆效果的影响,推导了多孔介质注浆深层渗滤理论,采用两个假设,F(σ)=1和浆液浓度c为常数,结合试验结果,对注浆过程中的压力变化进行了理论分析,通过对比分析验证了两个假设的合理性。在此渗滤效应研究的基础上,将可注性划分为三个阶段,分析了不同阶段内浆液颗粒的渗滤效应对注浆机理的影响。研发了三维注浆模型试验架,开展了水泥浆液的砂体注浆渗透试验,通过监测系统对注浆过程中的渗流压力和土压力进行了监测,获得了两个参数随时间的变化规律。注浆结束后通过清除模型填充体分析了浆液在砂层内的注浆扩散特征,对不同位置处的注浆结石体进行取芯并测试了其抗压强度,得到了抗压强度在水平面上的分布规律。结合中梁山隧道角砾岩破碎带高压大流量涌水治理工程,对不同注浆材料的力学性能、粘度性能、施工可控性、涌水封堵性能和围岩稳定性等方面进行了评价分析,对注浆材料的注浆性能进行了综合评价,对类似工程具有一定的借鉴意义。
【Abstract】 Grouting technique is a highly specialized academic branch of geotechnical engineering. In the process of operation, filling and cementation of grouting material are conducted for use of the consolidation of injected structure and water plug, as well as the modification of hydro-geological and engineering geological conditions, which is widely used in the special geological disaster governance of tunnel, mining and hydroelectric power station and other underground engineering, and also achieves remarkable effect. In the mean time, the investigation and application of grouting theory, construction technology and grouting material are developing rapidly, which generate an extensive variety of grouting material and its properties. In these materials, cement grout is composed of cement as main part, which contains Portland cement grout, sodium silicate cement grout and cement based polymer modified grout, which is widely used due to its merits of economy and friendly environment.Portland cement grout, which belongs to particle grout, was investigated on the aspect of porous media filtration, which has not been paid much attention to. This study mainly focuses on its deep bed filtration during penetration. Based on the common quick-setting cement grout, sodium silicate cement grout and cement based polymer modified cement grout, viscosity of time-dependent behavior test experiment is conducted, and the two kinds of grout viscosity time-varying characteristic and its engineering application are analyzed. On the basis of the results, the function relation between the grouting quantity and the pore diameter of the porous media, the grout concentration as well as the grouting pressure was obtained by regression analysis. Sand samples of different particle size were selected to conduct one dimensional long-column-type penetration test. Time-varying law of penetration pressure during grouting was studied with the consideration of the deep bed filtration effect. The influence of the deep bed filtration on grouting effect was analyzed. Theory of deep bed filtration of porous media was investigated. Two assumptions were adopted as follow:f(a)=1and the grout concentration is constant. With a combination of results, the pressure variation during grouting was analyzed, and the accuracy of the two assumptions was testified through comparison and analysis. On the basis of the study of filtration effect, the grouting capability can be divided into three stages. Influence of the filtration effect of the grout particles on the grouting mechanism in different stages was analyzed.Three dimensional grouting model testing system was established. Sand grouting penetration test using cement slurry was conducted. The change law of the two parameters was obtained, by monitoring the penetration pressure and the soil pressure during grouting. Grouting spread characteristics was analyzed, and the horizontal distribution of the compressive strength was obtained by coring consolidation mass in different position and testing its compressive strength.In combination with high pressure and large flow gushing water treatment project in fracture zone of zhongliangshan tunnel, makes an analysis of the different mechanical properties, viscosity properties of grouting material, construction control, gushing water plugging performance and surrounding rock stability influence, comprehensive evaluation on the applicability of grouting material, has a certain reference significance for similar projects.
【Key words】 prous media; cement-based grout; deep bed filtration; time-dependentbehavior of viscosity; engineering application;