Abstract: In order to evaluate the spudcan penetration and extraction effects on the adjacent piles, the free pile head model tests are carried out in clay under 1g conditions. The change laws of various physical quantities in the process are given by the model tests, and test data and testing methods for the subsequent centrifugal model tests are obtained. The model testing results show that when the spudcan penetrates deeper, the position where the maximum pile moment and the maximum soil displacement appear along the pile becomes deeper. As the spudcan elevates, the maximum pile moment and the maximum soil displacement decrease. However, after finishing of the model tests, the moment along the pile and the soil displacement do not return to their initial state. In the initial stage of the spudcan penetration, the resistance of the spudcan penetration increases rapidly and then gradually stabilizes. And the resistance of the spudcan extraction increases rapidly and then remains relatively stable during the initial stage of the spudcan extraction. When the spudcan shoe is about 120 mm away from the soil surface, the resistance suddenly drops to zero. The testing analysis results show that the displacement change of the soil mass directly leads to the change of the pile body response, and there is a positive correlation between them.