新型棉花秸秆排水体真空预压加固软基效果的研究

发布时间：2018-05-27 00:25

本文选题：棉花秸杆 + 真空预压　；参考：《安徽理工大学》2017年硕士论文

【摘要】：由于城市建设的发展和需求,大规模的围海造地工程在各地展开。工程用吹填软土特殊的性质决定了其作为软土地基的缺陷性,因此只有选择合适的技术对其进行加固处理才能解决软土地基的沉降和稳定性问题。目前,备受吹填软土地基加固工程青睐的方法主要是真空预压法。真空预压法离不开有效的竖向排水系统,而目前普遍使用的塑料排水板存在淤堵和弯折等技术性问题,高性能防淤堵塑料排水板在这种大规模的应用条件下,也面临着高成本的问题。为解决上述问题,不仅需要排水体在技术上革新,也需要在选材上革新。因此,结合我国目前农业发展的实际情况,考虑选取棉花秸秆捆作为竖向排水体。棉花秸秆具有天然优良的骨架、镂空、吸附等特性,取材方便,成本低,用它做竖向排水体并应用到临时加固处理软土地基中,将取得显著的经济效益并且有效缓解秸秆废弃物的弃置焚烧问题。为更好的研究棉花秸秆捆作为竖向排水体真空预压加固处理软土地基的可行性和最终效果,本文展开了一系列针对棉花秸秆捆排水固结效果研究的试验,主要内容如下:(1)进行土样的常规物理力学特性试验,得到土样的含水率、孔隙比、内摩擦角、粘聚力等基本参数。(2)通过单根棉花秸秆捆以及棉花秸秆捆群室内模型试验,对棉花秸秆排水体系排水机理、排水性能与排水规律进行分析总结。包括:研究秸秆排水体系的排水工作机理与排水性能;基于轴对称固结理论,明确棉花秸秆的有效影响范围及其影响范围直径与秸秆捆直径之比(井径比n)的范围,以及秸秆涂抹区直径与秸秆直径之比(s)的范围,建立秸秆排水体排水固结模型,利用有限元软件进行数值模拟,从而研究其排水规律。同时对竖向棉花秸秆捆排水效果的影响因素进行定量研究,建立棉花秸秆捆的初始密度、直径、间距等与其排水固结效果的内在关联。试验表明大直径小密度(ρ=0.0637g/cm3,d=45cm)的秸秆捆排水固结效果最佳,大而疏的排列方式下排水固结效果具有明显优势。
[Abstract]:Due to the development and demand of urban construction, large-scale land reclamation projects have been carried out. The special property of the soft soil used in the project determines its defect as the soft soil foundation, so the settlement and stability of the soft soil foundation can be solved only by selecting the appropriate technology to reinforce it. At present, vacuum preloading is the most popular method in soft soil foundation consolidation. The vacuum preloading method is inseparable from the effective vertical drainage system, but the plastic drainage board commonly used at present has technical problems such as blockage and bending, so the high performance silt prevention plastic drainage board is used in this large-scale application. Also face the problem of high cost. In order to solve the above problem, not only the technical innovation of the drainage system, but also the innovation in the selection of materials is needed. Therefore, considering the actual situation of agricultural development in China, cotton straw bundles are considered as vertical drainage body. Cotton straw has the characteristics of natural excellent skeleton, hollow, adsorption and so on. It can be used as vertical drainage body and applied to the temporary reinforcement of soft soil foundation. Significant economic benefits will be achieved and the problem of waste disposal and incineration of straw waste will be effectively alleviated. In order to better study the feasibility and final effect of cotton straw bundles as vertical drainage body vacuum preloading to treat soft soil foundation, a series of experiments were carried out to study the drainage consolidation effect of cotton straw bundles. The main contents are as follows: (1) the conventional physical and mechanical properties of soil samples are tested, and the basic parameters of soil samples, such as moisture content, porosity ratio, internal friction angle, cohesion and so on, are obtained. The drainage mechanism, drainage performance and drainage law of cotton straw drainage system are analyzed and summarized. Based on the axisymmetric consolidation theory, the effective range of influence of cotton straw and the ratio of the diameter of cotton straw to the diameter of straw bundles (well diameter ratio n) are defined, including: the study of drainage mechanism and drainage performance of straw drainage system, and the determination of the effective range of cotton straw based on the theory of axisymmetric consolidation. And the range of straw smear area diameter and straw diameter ratio, the drainage consolidation model of straw drainage body was established, and the finite element software was used to simulate the drainage law of straw drainage system. At the same time, the factors influencing the drainage effect of vertical cotton straw bundles were quantitatively studied, and the internal relations between the initial density, diameter and spacing of cotton straw bundles and the drainage consolidation effect were established. The experimental results show that the drainage consolidation effect of straw bundles with large diameter and small density (蟻 ~ (0.0637 g / cm ~ (3) ~ (45) cm) is the best, and the drainage consolidation effect with large and sparse arrangement has obvious advantages.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU472.33

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