Experimental investigation on load transfer characteristics of screw groove pile-geogrid composite foundation

As a new type of road composite foundation, screw groove pile-geogrid composite foundation can effectively reduce foundation settlement and improve foundation bearing performance. Model tests of circular pile-geogrid and screw groove pile-geogrid composite foundation are carried out to compare and study deformation of embankment, pile-soil stress ratio, load sharing ratio, strain of geogrid, and axial force distribution of piles. And further investigation on mechanical mechanism of pile-soil action of screw groove pile in pile-geogrid composite foundation are carried out. The results show that compared with traditional circular piles, the screw groove pile-geogrid composite foundation can reduce the settlement of the top surface of the embankment by 27.3%, which significantly improves the deformation control effect of the composite foundation. The material is only 52.1% of that of the circular pile. Screw groove pile-geogrid composite foundation can effectively regulate uneven settlements in both transverse and longitudinal directions of the embankment, and flexible raft of reinforced cushion is fully utilized. Under embankment loading, the pile-soil stress ratio of screw groove pile is significantly higher than that of circular pile-geogrid composite foundation, and the load sharing ratio of the piles rises by 11.8%. Screw groove pile utilizes multi-end bearing characteristics of the screw groove structure on the pile side and the superposition of the stress diffusion effect of the reinforced cushion to drive the soil around the pile to carry the load together, enhance the pile-soil-reinforced cushion interactions, significantly increase the utilization rate of the pile material, reduce the amount of cement, and promote carbon emission reduction.