The airport expansion project site features numerous ditches, ponds, and lakes, along with extensive soft soil and fill layers. The spatial and planar segmentation of the natural foundation by ditches and ponds heightens the risk of uneven settlement, subsequently impacting the normal use of the upper pavement structure. This paper conducted on-site experimental research in representative areas, thoroughly evaluating the depth of silt excavation, backfill materials, and compaction techniques. Based on the analysis of experimental results, the foundation treatment outcomes have been validated. This demonstrates the feasibility of the foundation treatment method employed in this project. Moreover, it offers a scientific foundation for the design and execution of extensive foundation treatments across the site.