Novel master consolidation curve for vacuum preloading with prefabricated horizontal drains in dredged marine deposits

Vacuum preloading with prefabricated horizontal drains (PHD-VP) has been shown to be an effective and rapid early-stage treatment method for ultra-soft dredged marine deposits. Using thickness-averaged void ratio as the state variable and a unified time factor, this paper proposes a novel master consolidation curve that provides a useful basis for consolidation prediction and stage-wise project management for PHD-VP under different site conditions within the range examined in this study. First, an idealized one-dimensional column test and a plane-strain physical model test are designed to construct the master consolidation curve, and its rationale is interpreted in terms of the final soil state and particle migration. Then, a field trial and reported PHD-VP cases are employed to validate the master consolidation curve. Furthermore, a large-strain consolidation calculation method with an elasto-viscoplastic constitutive law is used to simulate the observed histories, showing that variations in soil properties and drainage layout mainly influence the rate and extent of settlement development, while the overall form of the master consolidation curve is broadly preserved. Building on these insights, a practical procedure is proposed to identify the characteristic time from early-time settlement records, align project-specific data with the master curve and forecast consolidation progress and stage switching for field implementation.