Abstract: The physico-mechanical properties of suspended and fluid mud differ significantly from those of conventional soft soils. Therefore, using only the method of “correction by empirical coefficients of settlement calculation based on classical formulae” for calculating settlement in large areas of suspended and fluid mud foundations is unscientific. In response, this study established a total settlement calculation method for the intermittent settlement stage and the subsequent low-pressure (0−100 kPa) consolidation stage through theoretical derivation. Static intermittent settlement modeling tests were conducted to evaluate the validity of the batch settlement calculation method, and low-pressure consolidation tests were performed to assess the validity of the low-pressure consolidation settlement calculation method. The study results indicate that, 1) The cumulative change rate of average void ratio (r_e) and the low-pressure consolidation compression index (C_C-low) are two key technical parameters. The former can be determined by combining theoretical formulae with long-term static intermittent settlement modeling tests, while the latter can be determined through indoor low-pressure consolidation tests. 2) For suspended and fluid mud with a clay content of 40% to 60%, if static intermittent settlement modeling tests cannot be conducted, a “cumulative change in the average void ratio of 60% to 75%” can serve as a criterion for determining the stable state of static intermittent settlement. Specifically, when the clay content is 40%, r_e is 75%, and when the viscous grain content is 60%, r_e is 60%. This criterion also applies to Bingham bodies with no initial structure. 3) Determining the value of the low-pressure consolidation compression index based on the e-lgP (e is the pore ratio, P is the vertical compressive stress) using the slope averaging method is more reasonable. 4) The total settlement formula integrates the static intermittent settlement behaviors and low-pressure (0−100 kPa) consolidation behaviors, meeting the requirements for engineering accuracy. This study addresses the shortcomings of current research and provides scientific support for the design and construction of suspended and fluid mud foundation treatments.

Key words: foundation treatment, suspended and fluid, static intermittent settlement, low-pressure consolidation settlement, total settlement calculation