According to the engineering characteristics of pile foundation in soft soil layer, a virtual column structure model was proposed, and a theoretical solution to pile foundation settlement displacement was established. Besides, the load transfer characteristics of pile foundation in soft soil layer, the bearing mode of pile foundation, and its dynamic relationship with the gradual evolution of load and environmental conditions were studied. The results show that there are friction bearing and friction with pile end bearing modes in pile foundation, and they change significantly with pile top load, construction, and environmental factors. Affected by the load transfer law, there is a 0-axis force section in the axial direction of pile foundation. The relationship between the depth and the length of pile foundation affects the type of bearing mode and displacement calculation results. The field results verify the correctness and applicability of the theoretical method.

Keywords： bearing mode of pile foundation; settlement displacement; virtual column equivalent model; theoretical solution