高粘性高盐量吹填土固结过程孔隙分维特征

真空预压处理吹填土地基的方法应用广泛，但塑料排水管经常会被吹填土细颗粒堵塞。为提高吹填土造陆效率，通过室内试验，研究了高粘性高盐量吹填土在自重沉淤和加负压联合作用下的固结规律,分析了吹填土取土点的工程地质特征。用易溶盐试验和X射线衍射分析方法确定吹填土中晶体的类型，并结合自重固结不同阶段的扫描电子显微镜微观结构照片，研究吹填土含盐量对排水效果的影响,总结高粘性高盐量吹填土固结排水时渗流通道变化规律。研究发现，随着吹填土含水量降低，晶体颗粒随水流失，渗流通道则处于不断变化的非稳定状态。同时，将分维数作为研究高粘性高盐量吹填土的微观结构指标，发现随着自重固结程度的增加，高粘性高盐量吹填土含水量减少，颗粒表面吸附能力下降，晶体颗粒逐渐脱离土颗粒表面，使土体孔隙和结构单元体颗粒发生规律性变化。

Fractal Dimension of Porous of Heavy Clay and Saliniferous Dredger Fill During the Process of Consolidation

The dredger fill foundation is popularly treated by vacuum preloading. But the drain pipes are always clogged by fine particles which cause the construction to be delayed. In order to improve the efficiency of the dredger fill consolidation, a laboratory test was designed to study consolidation law under the comditions of gravitational drainage clogged combined with vacuum preloading method for heavy clay and saliniferous dreder fill. Engineering geology characteristics of heavy clay and saliniferous dredger fill was analyzed. And the small cubic crystals overlapped on the surface of the particles were identified by soluble salts test and X-ray diffraction approach. When the microstructure was studied by scanning electronic microscope (SEM) during the process of consolidation, it was indicated that with the decreased of moisture content in heavy clay and saliniferous dredger fill, the number of halite was running off by water drainage in the process of gravitational drainage stage. So the seepage channels became instability due to the unstable microstructure. Furthermore，particle fractal dimension was taken as the microstructure index to determine the characteristics of the heavy clay and saliniferous dredger fill on the process of consolidation. The results showed that particle fractal dimension was increased by consolidation as the result of the reduction of the number of cubic crystals flowed off by water drainage.