The method of vacuum preloading for foundation treatments is used in the construction of the Fangchenggang coastal area in Guangxi province, China. The thick marine dredger-filled silt has a considerable impact on the treatment effort. In this study, the mineral composition and grain size distribution of these silts were analyzed to investigate their consolidation settlement property and microstructures. The scanning electron microscope and finite element method were adopted. The results reveal that the dredger-filled silt in this area is composed mainly of sand with particle size mostly smaller than 0.075 mm. To replicate the construction process, the process of drainage by the vacuum preloading method was simulated by setting different water levels in the finite element analysis. The displacement and the dissipation of the pore water pressure obtained by simulations were reasonably consistent with the field monitoring data. In addition, the results obtained using the scanning electron microscope indicate that the equivalent diameter of the structural unit and that of the pore unit decrease with the silt depth. However, the value of the structural abundance approaches one, whereas the pore abundance is significantly different from one.

中文翻译：

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船用挖泥船填充淤泥的真空预固结沉降特征及微观结构演化

地基处理真空预压法用于广西防城港沿海地区的建设。厚厚的海洋挖泥船填充的淤泥对处理工作产生了相当大的影响。在这项研究中，分析了这些粉砂的矿物组成和粒度分布，以研究它们的固结沉降特性和微观结构。采用扫描电子显微镜和有限元方法。结果表明，该区挖泥船充填的淤泥主要由粒径小于0.075 mm的砂组成。为了复制施工过程，通过在有限元分析中设置不同的水位来模拟真空预压法排水过程。模拟得到的孔隙水压力的位移和消散与现场监测数据基本一致。此外，扫描电子显微镜的结果表明，结构单元的等效直径和孔隙单元的等效直径随着淤泥深度的增加而减小。然而，结构丰度的值接近1，而孔隙丰度的值与1显着不同。