Influence of Curing Age on the Bearing Capacity of Short-Core SDCM Piles: Insights from Theoretical Analysis and Laboratory Model Tests

Abstract The vertical bearing capacity of stiffened deep cement mixing (SDCM) piles is closely related to curing age. In short-core SDCM piles, in which the core length is shorter than the reinforced depth of the cemented soil, the relatively large proportion of cemented soil makes the bearing behavior highly sensitive to the mechanical properties of the cemented soil and the pile–side interfaces, both of which evolve with curing age. This study develops a theoretical framework to predict the evolution of their vertical bearing performance. The framework incorporates a generalized hyperbolic model to simulate the strength and stiffness development of cemented soil, while the shear interactions at the pile–soil and pile–pile interfaces are characterized by a disturbed state concept–based evolution model. The pile-end resistance is represented by an exponential function, and the governing load-transfer equations are solved numerically through the finite-difference method. Laboratory model tests on short-core SDCM piles cured for 14, 28, 60, and 90 days under consistent conditions were conducted to validate the proposed model. The bearing capacity of the test piles increased rapidly within the first 28 days and gradually stabilized after approximately 60 days of curing. Theoretical predictions agree well with both laboratory and in situ test results, confirming the reliability of the framework. The results indicate that both cemented-soil strength and core-pile geometry influence the curing period required to reach the stabilized bearing capacity, providing useful guidance for the design and construction control of short-core SDCM piles.