Abstract:

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.

Key words: heavy clay and saliniferous dredger fill, porous, microstructure, fractal dimension