Study on uplift characteristics and group effects of strength composite piles

Strength composite piles are newly developed pile types recently. Current research primarily focuses on their compressive load-bearing performance, while the characteristics of strength composite piles under uplift forces and their group pile effects remain uncertain. In light of this, the factors affecting the uplift characteristics of strength composite piles and their group effects are studied through field tests and numerical simulations. The results indicate that compared to conventional piles, the side friction of strength composite piles increases by about 80%. The increase in pile length, pipe pile diameter and cement-soil modulus can effectively improve the ultimate uplift-bearing capacity of strength composite piles. The group pile effects of strength composite piles subjected to uplift load are significant. Increasing the pile length has the most significant improvement measure for improving the group pile effect. As a force transmitting component in strength composite piles, cement soil piles form an important pathway for shear stress transmission through their internal and external interfaces with pipe piles and soils around the piles. Improving the performance of cement soil piles can increase their bearing capacity to a certain extent.