Abstract: The construction of pile group foundations and underground diaphragm walls generates a significant amount of waste mud. Similarly, the development and utilization of urban underground space, as well as the process of shield tunneling, result in the production of high-moisture mud-like slag. Conventional yard treatment is limited due to cost and environmental concerns. Thus, an efficient dewatering method is needed to reduce waste mud volume. To evaluate the dewatering effect of flocculant conditioning on waste mud and enhance dewatering efficiency, we employed single and composite flocculants to examine the influences of type and dosage of flocculants on mud-water separation and sought to establish a basis for assessing dewatering effectiveness. Our findings demonstrate that organic flocculants enhance dewatering performance and promote mud-water separation, with an optimal dosage. Moreover, composite flocculants exhibit a synergistic effect from both organic and inorganic components, further enhancing dewatering capacity. Specifically, PAM composite flocculant has excellent dewatering performance. The combination of PAM and CaO composite flocculants could reduce the water content in sedimentary layer by 82.75%.

Key words: mud, organic flocculant, composite flocculant, mud-water separation, dewatering effect, heap load preload, evaluation index