Test and numerical simulation on bearing performance of post-grouted rotary drilled piles

Post-grouting is a widely used pile foundation reinforcement technology in high-rise and large-span buildings. Many engineering practices have verified that this technology can effectively improve the bearing capacity of pile foundations. According to the construction needs of a project in Chengdu, Sichuan, two sets of static load tests were conducted on four post-grouting rotary drilled piles. Based on the test results, numerical simulations were used to study the stress and displacement distributions of the test piles under different grouting conditions, and the effects of the amount of grout injected into the pile side and pile end on the bearing capacity of the foundation were further investigated. The results show that the rotary drilled pile reinforced by post grouting technology has high bearing capacity and safety reserves. The side grouting of the pile mainly drives a larger range of rock mass on the pile side to participate in bearing the load through side resistance and the compression effect at the bottom of the grouting body, reducing the deformation and settlement of the pile body; Grouting at the pile tip can form a high-strength grouting body, improving the stress transmission state at the pile end, thereby preventing the rock mass at the pile end from yielding under compression and reducing its deformation; Changing the length of grouting at the pile side and the thickness of grouting at the pile end can affect the ultimate bearing capacity of the foundation, and the effect of the thickness at the pile end is more significant.