Project difficulties and solutions:

The engineering geological conditions in the sea reclamation fill area are complex, with large boulder clusters and a cobble layer up to 4.5 meters thick. The verticality deviation of steel sheet pile construction must be controlled within 1/200 to ensure no leakage occurs in the foundation pit. The project used a vibratory hammer combined with guide holes to achieve one-pass forming of steel sheet piles in the cobble layer. For some leakage points that appeared after excavation, dual-fluid grouting was used for plugging and reinforcement, ensuring no leakage on the pit side walls and controllable deformation; the daily tidal range reaches 2.8 meters, and the high tide level (3.1m) is only 23cm from the pit top (3.33m). The support structure is subjected to enormous impact pressure from the tide. The project used two/three levels of Φ609 steel pipe bracing with 200t hydraulic jacks to apply prestress, ensuring foundation pit deformation is controlled within 20mm; to ensure the safety of foundation pit support, 12 piezometers, 4 inclinometers, 15 steel pipestress gaugesand 15 foundation pit horizontal displacement observation points were installed around the foundation pit to ensure deformation remains within the dynamic control range.

The project innovatively adopted an integrated "design-construction-monitoring" management model. Through refined design, standardized construction, and intelligent monitoring, the project team dynamically adjusted design and construction parameters, successfully controlling foundation pit deformation within 9.8mm and achieving the goal of "zero leakage, zero accidents," accumulating valuable experience for CABR Foundation's construction in complex coastal environments.