Fully recoverable retaining technology of sheet piles anchored by steel pipe piles for excavations and model tests

In light of the issues such as inefficiency of retaining component utilization, environmental contamination and excessive carbon emissions associated with excavation engineering, a fully recoverable retaining technology of sheet piles anchored by steel pipe piles is proposed for excavations, and the composition of the retaining system is introduced. A large-scale scale model test is conducted, and the displacements of the sheet piles and pipe piles during excavation are quantitatively measured using the photogrammetry such as DIC and DPA. The test results indicate that the anchorage action of the pipe piles imposes a significant constraint on the structural displacement, and the displacement can be effectively mitigated by increasing the number of pipe piles per unit width. The displacement at the top of the pipe pile exhibits a hyperbolic relationship with the excavation depth. The deformation and failure mechanism of the model foundation are associated with the distance between the pipe piles and the sheet piles. As the distance increases, the failure mechanism varies from the concurrent inclination of the pipe piles and sheet piles to the slippage along the pipe piles, and subsequently to the slippage along the surface area extending about 1.5 times the excavation depth from the sheet piles. The deformations at the top of both the pipe piles and the sheet pile remain consistent throughout the excavation process.