不同地质条件下真空注浆模拟试验研究

发布时间：2018-08-30 10:27

【摘要】：注浆技术作为一种行之有效的地基(地层)处理方法。目前在土木、交通、水利、矿山等许多领域中得到了广泛的应用。然而实际工程中,不少被注浆地层含细砂或粉砂土层,采用普通的静压等传统注浆工法很难实现有效灌注或无法实现设计扩散半径。针对这种情况,最近提出了一种新的注浆方法,真空注浆法。真空注浆即是将真空技术应用于注浆工程,在土体中设置真空井抽吸被注浆土体中的空气,使土体产生负压,增加真空井与注浆孔之间的孔压差,达到在不增加外部静压力的情况下就能达到形成孔压差的目的,进而使浆液注入到土体中。本文通过室内三维真空注浆模拟试验及真空定向注浆模拟试验,对真空注浆在无气流流动和有气流流动两种工况下进行了研究。本文的主要研究内容及取得的几点认识包括：(1)首先针对真空注浆的特点,设计并研制室内模拟试验模型及其密封方法。(2)通过三维真空注浆模拟试验,得到了不同地质条件下在不同真空度时浆液的扩散半径,总结出了浆液的扩散规律及注浆流量的变化规律。并运用Maag公式计算得出浆液扩散半径的理论值,通过浆液扩散半径实际值与理论值的对比,发现一般情况下,实际扩散半径均比理论扩散半径小；同种真空度条件下,随着地层渗透系数的增大,扩散半径理论值与实际值之间的差值在增加。(3)通过真空度测试可知,真空度的分布规律对真空定向注浆效果影响较大,在实际工程中,可以通过设置进气井,改变土体内负压区边界及真空场分布,进而影响浆液的扩散,以达到需要的定向注浆效果。(4)通过真空定向注浆模拟试验,得到了注浆管两侧扩散半径随着注浆真空度的变化规律,真空定向注浆扩散效果随着真空度的增加越来越明显。
[Abstract]:Grouting technology is an effective treatment method for foundation (stratum). At present, it has been widely used in many fields, such as civil engineering, transportation, water conservancy, mining and so on. However, in practical engineering, many grouting strata contain fine sand or silt soil, so it is difficult to realize effective grouting or design diffusion radius by using conventional grouting methods such as hydrostatic pressure. In view of this situation, a new grouting method, vacuum grouting, has been proposed recently. Vacuum grouting is the application of vacuum technology in grouting engineering. A vacuum well is set up in the soil to draw air from the soil to produce negative pressure and increase the hole pressure difference between the vacuum well and the grouting hole. The pore pressure difference can be formed without increasing the external static pressure, and then the slurry can be injected into the soil. In this paper, the three dimensional vacuum grouting simulation test and the vacuum directional grouting simulation test are used to study the vacuum grouting under the two conditions of airflow and airflow. The main contents of this paper are as follows: (1) according to the characteristics of vacuum grouting, an indoor simulation test model and its sealing method are designed and developed. (2) through three-dimensional vacuum grouting simulation test, The diffusive radius of slurry under different geological conditions under different vacuum degree is obtained, and the diffusion law of grouting fluid and the variation law of grouting flow rate are summarized. The theoretical value of the slurry diffusion radius is calculated by using Maag formula. By comparing the actual value with the theoretical value, it is found that the actual diffusion radius is smaller than the theoretical diffusion radius under the same vacuum condition. With the increase of formation permeability coefficient, the difference between the theoretical value of diffusion radius and the actual value is increasing. (3) through the vacuum degree test, it can be seen that the distribution law of vacuum degree has a great influence on the effect of vacuum directional grouting. The boundary of negative pressure zone and the distribution of vacuum field in soil can be changed by setting intake well, and then the diffusion of slurry can be affected, so as to achieve the desired directional grouting effect. (4) through the simulation test of vacuum directional grouting, The variation of the diffusion radius of the two sides of the grouting pipe with the grouting vacuum degree is obtained, and the effect of the vacuum directional grouting diffusion becomes more and more obvious with the increase of the vacuum degree.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU753

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