Abstract: The high-water-content and quick-setting materials are a new kind of cement with many unique properties: 1. high water content; 2. quick setting and strengthening; 3. long pumpability time; 4. good plasticity; 5. the property of re-developing strength after ultimate loading. Although having been widely used in coal and metallurgy systems with remarkable technological and economical benefits, the materials have not yet been applied to geotechnical engineering. In order to explore the foreground of applying the materials to the soft soil foundation, the study on the microstructure of the soft soil with the materials is conducted by SEM. The results show that there only exists the geometrical drift of sedentary minerals without firm connection among the pure soil particles. However, the soil structure completely changed with materials added to it. In the consolidated soft soil-materials, the principal structure is the “spatial cellular structure” of calcium crystal. The supplementary structure is the micro-crystal and gel structure which is formed among the soil particles in alkaline environment through ion exchange, aggregation and carbonation. Thus, the materials may have a good foreground of application to ground treatment.

Key words: high-water-content and quick-setting materials, soft soil mixed with high-water-content and quick-setting material, microstructure, scanning electron microscope（SEM）