吹填场地软土地基变形特性及桩负摩阻力研究

发布时间：2018-05-25 17:15

本文选题：次固结 + 吹填土　；参考：《天津大学》2014年硕士论文

【摘要】：在围海造陆过程中,吹填土将经历由液态泥浆向具有一定强度的可塑态土体的复杂转化,伴随吹填土的结构变化,其工程特性也逐渐发生着变化。吹填土承压强度很小、受荷时压缩变形大、渗透性差,与其下部的天然土层存在较大的差异。然而,目前对于吹填场地由不同成因所造成的各深度土层的工程特性差异研究却少见于报端。工程实践却表明,经加固的吹填土其下部土层不仅是控制地基承载力的关键,也是固结沉降的主要发生部位。故有必要加强对吹填场地各不同深度土层工程特性差异的研究,并在此基础上提出吹填场地的次固结变形预测模型,以期为工程实践提供理论支撑。本文针对天津滨海新区中心渔港真空预压已处理吹填场地不同深度土层进行了大批室内次固结试验研究,得到了如下主要结论:提出了吹填土次固结试验操作方法,弥补了土工试验规程相应部分所存在的空白,该方法有望可作为今后相关规范或规程的补充内容。对吹填场地不同成因的各土层进行了大量的室内一维次固结试验研究,分析了不同成因的各土层(吹填土层、含塑料插板的天然土层、塑料插板以下的天然沉积土层)工程特性,并由此得出真空预压的影响深度约为20m。利用单向压缩分级加载试验,经过对试验成果整理分析,结合对吹填场地土次固结特性的研究,并在Mesri和Godlewski研究的基础上,建立了次固结系数的预测模型,并在此基础上进一步推导得到了次固结变形的预测模型,通过试验值与计算值的对比验证了该模型是适用于天津吹填场地的。利用ABAQUS软件建立桩土接触共同作用模型,分析了中心渔港地区桩侧摩阻力在堆载作用、桩顶荷载、时间效应以及群桩效应等因素的影响下,桩侧摩阻力随深度变化的分布规律。
[Abstract]:During the process of reclamation, the filling soil will undergo complex transformation from liquid mud to plastic soil with a certain strength, and its engineering characteristics will change gradually along with the structural changes of the filling soil. The pressure bearing strength of the filling is very small, the compression deformation is large and the permeability is poor, which is different from the natural soil layer in the lower part. However, at present, the research on the engineering characteristics of different depth soil layer caused by different causes of backfill site is seldom seen in the newspaper. The engineering practice shows that the underlying soil is not only the key to control the bearing capacity of the foundation, but also the main site of consolidation settlement. Therefore, it is necessary to strengthen the study on the difference of engineering characteristics of different depth soil layers in the filling site, and on this basis, to put forward the prediction model of secondary consolidation deformation of the filling site, in order to provide theoretical support for engineering practice. In this paper, a large number of indoor secondary consolidation tests were carried out on different depth soil layers of the central fishing port of Tianjin Binhai New area. The main conclusions are as follows: the operation method of the secondary consolidation test is put forward. The method is expected to be used as a supplement to the relevant codes or regulations in the future. In this paper, a large number of indoor one-dimensional secondary consolidation tests were carried out on each soil layer of different origin of blowing site, and the soil layers of different origin (blowing soil layer, natural soil layer containing plastic insert board) were analyzed. The engineering properties of the natural sedimentary soil layer below the plastic inserting plate) are obtained, and the influence depth of vacuum preloading is about 20m. A prediction model of secondary consolidation coefficient is established on the basis of Mesri and Godlewski by unidirectional compression and graded loading test, through the analysis of test results, combined with the study of the secondary consolidation characteristics of the soil in the blowing site, and on the basis of the research of Mesri and Godlewski, the prediction model of the secondary consolidation coefficient is established. On this basis, the prediction model of secondary consolidation deformation is derived, and the comparison between experimental and calculated values proves that the model is suitable for Tianjin fill site. The pile-soil contact interaction model was established by using ABAQUS software, and the distribution law of pile-side friction with depth was analyzed under the influence of pile load, pile top load, time effect and pile group effect under the influence of pile side friction in central fishing port area.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU447

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