Abstract:Abstract: Geological characters of dredger fill have been studied in recent years and the engineering geological properties of dredger fill is comprehensively affected by the material composition and microstructure. Because there’re many difficult factors such as sampling and sample preparation, microstructure is indispensable but seldom involved in the former research. Taking the dredger fill in Tianjin Binhai New Area as study object, the mineral composition is identified by X-ray diffraction approach, and the microstructure is studied by scanning electronic microscope (SEM), along with quantificational analysis of the microstructure using WD-5 picture processing system. And then the changing of evaluation indicators in two different reinforcement approaches, such as the size of structure element and pore, abundance, and directional frequency are discussed. The conclusion indicates that after water drainage treatment, the porosity becomes smaller, the dispersed structural elements of soil become agglomerated elements, displaying a variety of oblate. Simultaneously, the pores in the soil are diminished and lose balance, and directing property becomes indistinct. Consolidation degree of soil becomes higher.