Model test and numerical simulation data of post-grouting piles

To study the compressive bearing characteristics of post grouting piles, the variation laws of axial force and lateral friction resistance of pile side grouting piles under downloaded load were analyzed through indoor proportional model tests. By combining finite element numerical simulation, the compressive bearing characteristics and load transfer laws of pile end grouting piles, pile end grouting piles, and pile end pile side composite grouting piles were analyzed. The results indicate that these three pile types can effectively improve the ultimate bearing capacity of piles; The length of grouting on the pile side (n, 0 ≤ n ≤ 1) has a significant impact on the ultimate bearing capacity of the grouted pile on the pile side. When n ≤ 0.6, its ultimate bearing capacity significantly increases. Then, as n increases, the ultimate bearing capacity increases limitedly, indicating that due to the larger lateral stress in the lower soil, the grouting on the lower pile side more effectively improves the compressive bearing capacity. It also indicates that the optimal n value for pile side grouting is 0.6; The ultimate compressive bearing capacity of grouted piles and composite grouted piles increased by 17.6% and 32%, respectively, compared to non grouted piles, which increased by 4%. When the compressive load at the top of the pile is 5.1kN (the characteristic value of the bearing capacity of the grouted pile), the settlement at the top of the pile decreases by 24.7% and 50.6%, respectively. From the perspective of axial force on the pile, both of them can better exert the lateral frictional resistance of the lower pile compared to the pile side grouting pile.