Model Tests on the Evolution of the Influential Zone in GRPS Runway Subjected to Aircraft Landing

Geosynthetic-reinforced pile-supported (GRPS) foundation, extensively constructed as a soil improvement beneath highways and high-speed railways, has recently been increasingly adopted in the flight areas of airports in coastal cities. However, considering the differences in the applied loads, especially aircraft landing, and the lack of instructions in the aviation industry to consider the cyclic effects after construction, it is a necessity to investigate the effects of repeated aircraft landings on the GRPS runway. A series of small-scale model tests were conducted considering different aircraft types, fill heights, and pile spacings, where the variations of pavement settlement, soil arching ratio, and influential zone dimensions within the pile–soil composite with landing times are focused. The weakening effect of repeated landing on soil arching is verified, and an empirical formula for the influential radius with depth is proposed to evaluate variations in pile response with different GRPS runway configurations. It is found that, under the test conditions, the lateral and vertical dimensions of the influential zone can be up to 7 and 20 times the wheel track (St), respectively, and increase with increasing pile spacing, decreasing fill height, and larger overall aircraft weight.