Sand Deposit Arrangement and Construction Optimization for Large-section Immersed Tube Tunnel Foundations via the Sand Flow Method

This study analyzes the distribution of the flow field in a foundation trench under different sand deposit arrangements based on the assumption of uniform sand-water mixed flow. Based on the influence of the sand deposit boundaries, this study investigated sand deposit arrangement and construction optimization. Results show the density of the sand deposit in parallel and alternative sand deposit arrangements. Sand deposits should be arranged symmetrically to simplify the sand deposit boundaries during construction to guarantee the overlapping of sand deposits in a large area and to prevent a sharp boundary from being produced. During sand deposit construction, regional linkage with the external water flow and symmetrical construction should be maintained to reduce sharp intersections between haped sand deposits. The sand-filling sequence for a large section of immersed tube tunnel with multirow sand deposits should be middle first, followed by each side.