Pneumatic Sinking 2.0: A World Record Caisson Project by Large Scale Innovations-Paper

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The paper describes “Pneumatic Sinking 2.0,” a remotely controlled method developed to sink exceptionally large caissons while reducing workers’ exposure to hazardous, time-limited hyperbaric conditions. The system uses extendable, rotating arms fitted with cutting-head pumps, supplemented by ceiling-mounted water jets to move soil toward the pumps. Sensors, cameras and real-time monitoring track equipment performance, soil removal and caisson movement.<br /><br />The method was applied to two gate chambers for the new sea lock at IJmuiden, near Amsterdam. The largest caisson measured 55 × 81 m, weighed about 150,000 tonnes and was sunk to approximately 25.5 m below Dutch datum. Its open, flexible structure was vulnerable to bending and torsion, making precise control of differential settlement essential.<br /><br />Engineers combined large-strain Abaqus analyses, Plaxis modelling and Brinch Hansen bearing-capacity calculations to understand how supporting soil berms deform and fail. The analyses indicated that berm-slope deformation and deeper sliding mechanisms are mobilized in sequence, producing controlled, small sinking steps rather than sudden collapse. Results informed berm dimensions, soil-pressure limits and execution tolerances.<br /><br />During construction, operators used real-time measurements and regular inspections to adjust excavation and keep deformations within prescribed limits. Both caissons reached their final positions successfully, with the largest meeting the project’s positional and torsional tolerances. Observed soil behaviour broadly matched the predictions.<br /><br />The authors conclude that remote operation can improve productivity and reduce staffing compared with traditional manual excavation, while monitoring and the observational method enable accurate control. They recommend combining analytical methods, recognizing their respective limitations, and adopting conservative soil-strength assumptions during the critical start-up phase of similar projects.

Keywords

Pneumatic Sinking 2.0

caisson sinking

remotely controlled excavation

hyperbaric conditions

sea lock IJmuiden

soil berm stability

Abaqus analysis

Plaxis modelling

Brinch Hansen calculations

real-time monitoring