The influence of the tamping mode on the clogging effect of the vacuum-dynamic drainage consolidation method

• Published in: Arabian journal of geosciences Vol. 15; no. 2
• Main Authors: Li, Xiaobing, Li, Jun, Yuan, Guohui, Fu, Hongtao
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 2022; Springer Nature B.V
• Subjects: Clogging; Consolidation; Drainage; Earth and Environmental Science; Earth science; Earth Sciences; Energy; Hydraulic fill; Hydrostatic pressure; Original Paper; Permeability; Pore pressure; Pore size; Pore water; Pore water pressure; Prefabrication; Shear strength; Soil; Soil dynamics; Soil permeability; Soil settlement; Soil strength; Soils; Tamping; Vacuum; Vertical drains; Water discharge; Water pressure; Tamping sequence; Vacuum-dynamic drainage consolidation method; Clogging effect; Tamping mode model tests; Tamping energy
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-021-09421-0

During a vacuum consolidation, due to the faster consolidation rate at the zone near the prefabricated vertical drain (PVD), a lower-permeability zone will be formed around the PVD, reducing the radial propagation rate of the vacuum pressure. Thus, a vacuum-dynamic drainage consolidation method was proposed to alleviate the clogging effect of a “soil column” produced in the vacuum preloading process. A series of model tests for different tamping modes (a combination of tamping sequence and energy) are conducted in this study. The vacuum pressure, water discharge, excess pore water pressure, surface settlement, intergranular pore, and soil shear strength changes were also analyzed. The results indicate that, under the vacuum-dynamic drainage consolidation, which uses low energy to tamp the soil near the PVD after using high energy to tamp the ground near the periphery of the model, the water discharge amount increased faster, and the final discharge volume was more significant than that obtained under the other methods. The relative settlement of the vacuum-dynamic drainage consolidation method is about 1.47 times that of the traditional vacuum preloading method. At the same time, the pore size results between the soil particles prove that the relatively high-energy tamping energy is used to ram the soil around the model barrel, and then the low-energy tamping energy is used to ram the soil near the PVD unit, which can be more effective in strengthening. Wenzhou hydraulic fills the ground to make it suitable for a broader range of construction land requirements.