This paper evaluates the geological conditions of a wharf project on the lower Yangtze River and, in light of the stratigraphic characteristics, particularly the challenge of penetrating dense sand layers, implements the PHC–steel composite pile technique. A comparative analysis of the design predictions and in-situ pile load test results is conducted to verify the feasibility of this method in such subsurface conditions. The findings offer a technical reference for the wider adoption of PHC–steel composite piles in dense sand layer environments.