Centrifuge modeling of the settlement and deformation of runway under cyclic impact load

A new device has been developed to simulate the cyclic impact load of aircraft in centrifuge model tests, enabling automatic control over the number of cycles and impact velocity. A series of centrifuge model tests were conducted using this device to analyze the influence of cyclic impact load on runway settlement and deformation. It is observed that a single impact leads to significant settlement initially, which eventually stabilizes over time. Higher impact loads require fewer impact numbers for the soil base to attain a stable state. The maximum vertical displacement of the soil base is located at the impact center line and diminishes with distance from the impact center line. Based on the vertical displacement of the soil base, the loading influential zone is demarcated as the near-ellipse shape. The formation process of the loading influential zone gradually proceeds from base surface to deeper base, and finally attains a state of stability. The vertical strain of foundation is used to describe the deformation, the soil deformation beneath the concrete pavement plate is relatively significant, with a decreasing trend as it moves away from the impact center line. Under the same impact load in shallow foundation, the point at which the vertical strain decreases to zero becomes approximately linear. Based on the concrete analysis of the settlement in each cycle, the evolution mechanism of the soil base under cyclic impact load is revealed. The soil initially shows predominantly plastic deformation, which transitions to predominantly elastic deformation in the later stages.