真空预压加固技术中真空井作用范围的研究

发布时间：2018-03-03 08:36

本文选题：软地基　切入点：真空预压法　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着城市基础设施、道路和铁路建设的进一步加快,土地合理利用要求以及线路技术要求的提高,工程中不可避免会遇到软地基的处理问题。软地基处理方法多种多样,其中真空预压法由于其工程量小、成本较低和对环境影响较小等优点,在软地基处理中得到广泛应用。然而真空预压法使用过程中发现,排水板常常出现弯曲变形、堵塞和处理深地基效果不明显等问题。近年来,工程界采用真空井代替了传统排水板的方法,该方法不仅解决了排水板弯曲的问题,也加大了地基处理深度。但是在实际实施中,真空井的合理作用范围却受制于各种条件的限制,作用范围的确定大多依靠工程人员的经验。因此本文通过理论和试验研究方法,开展有关真空井作用范围的研究,为实际工程提供一定的借鉴作用。本文首先对文献资料分析,认为采用排水板真空预压法会出现排水板弯曲、堵塞和加固深度有限等问题,并分析了出现这些问题的原因。对工程中采用的真空井代替排水板加固软地基的真空预压法新技术进行了分析,认为该方法加固深度更大,并且可避免如排水板弯曲变形而降低软土地基固结作用效果。同时分析了该方法在实际应用中可能存在许多不确定的因素,而造成固结沉降效果不佳。本文以土体微观学作为理论研究基础,分析得出渗透系数和孔隙比越大,则土体压缩模量越小的结论,再结合真空预压法得出加固后地基沉降量与地基承载力值的关系,继而提出沉降量计算出真空井的作用范围的方法。通过室内试验方法,按照真空预压加固技术原理,对三种典型土体砂土、淤泥质土和粘性土沉降量进行实测,在试验模型条件下测定出三种土体距离真空井由远及近沉降量分别为:2.4cm～3.1cm、3.9cm～6.7cm、3.3cm～6.2cm,理论沉降量由远及近分别为:1.6cm～2.5cm、3.7cm～6.3cm和2.7cm～5.8cm,通过结果对比发现实测沉降规律与理论值基本吻合。
[Abstract]:With the further acceleration of urban infrastructure, the construction of roads and railways, the improvement of the requirements of rational land use and the technical requirements of railway lines, the problems of soft foundation treatment will inevitably be encountered in engineering. There are various methods for soft foundation treatment. The vacuum preloading method is widely used in soft foundation treatment because of its advantages of low engineering quantity, low cost and small environmental impact. However, it is found that the drainage plate often appears bending deformation during the use of vacuum preloading method. In recent years, the method of vacuum well instead of traditional drainage plate has been adopted in engineering field, which not only solves the problem of drainage plate bending, But in practice, the reasonable range of action of vacuum well is limited by various conditions, and the determination of the scope of action mostly depends on the experience of engineers. Therefore, in this paper, through theoretical and experimental research methods, The study on the action range of vacuum well can be used for reference in practical engineering. Firstly, the paper analyzes the literature, and points out that the drainage plate bending, blockage and reinforcement depth will occur by using vacuum preloading method of drainage plate, and so on. The causes of these problems are also analyzed. The new vacuum preloading method used in the project to replace the drainage plate for strengthening soft foundation is analyzed. It is considered that the depth of the method is greater than that of the vacuum preloading method. And it can avoid the bending deformation of drainage plate and reduce the consolidation effect of soft soil foundation. At the same time, many uncertain factors may exist in the practical application of this method. But the effect of consolidation settlement is not good. In this paper, the microcosmic soil is taken as the theoretical basis, and the conclusion is drawn that the larger the permeability coefficient and the porosity ratio, the smaller the compression modulus of soil. Combined with the vacuum preloading method, the relationship between the settlement of the reinforced foundation and the bearing capacity of the foundation is obtained, and then the method of calculating the range of action of the vacuum well by the settlement is put forward. The settlement of three kinds of typical soil sand, silt and clayey soil was measured. Under the experimental model condition, three kinds of soil from far and near to vacuum well were determined to be: 1 2.4 cm ~ 3. 1 cm ~ 3. 9 cm ~ (-1) cm ~ (3. 9) cm ~ (3) ~ (3) cm ~ (-1) ~ 6 ~ (2) cm ~ (-2) cm ~ (-1), and the theoretical settlement value of 3. 3 cm ~ 6 ~ 2 cm ~ (-3) cm ~ (-1) from far to near is found to be 6. 3 cm and 2. 7 cm ~ (5) cm ~ (-5) cm ~ (-1), respectively.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU472.33

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