Abstract: To address the low dewatering efficiency and prolonged occupation period of traditional dredged sludge yards, a novel ring-type tube stockyard sludge storage and dewatering technology was proposed. Long-term laboratory experiments were conducted to investigate the dewatering dynamics, focusing on the synergistic effects of geotextile filters and dimensional parameters. The mathematical expressions for each stage of the sludge dewatering process in the ring-type tube stockyard were clarified. The results indicate that in a double-layer ring-type tube stockyard without a geotextile membrane, the sludge dewatering process consists of three stages: solid-liquid separation, seepage, and evaporation, which change linearly, exponentially, and linearly, respectively. In a double-layer ring-type tube stockyard with a geotextile membrane, the sludge dewatering process is divided into four stages. The dewatering rates in the solid-liquid separation and seepage stages are significantly accelerated, leading to improved overall dewatering efficiency. Mechanistically, this acceleration results from the geotextile membrane’s effectiveness in preventing solid sludge particles from clogging the inter-thread gaps in the ring-type tubes. In an eight-layer ring-type tube stockyard, the sludge dewatering process is divided into five stages, introducing a linear change stage of sudden settlement compared to the double-layer stockyard. The mathematical descriptions of the other stages are similar to those of the double-layer stockyard. As the ratio of yard height to inner diameter increases, the sludge settlement distribution takes on an “inverted cone” shape, with maximum settlement occurring at the center, thereby enhancing overall dewatering efficiency. These findings are crucial for the efficient utilization of limited storage space for dredged sludge.

Key words: ring-type tube stockyard, indoor model test, sludge sedimentation, dewatering characteristics, reduction of sludge