Bond–Slip Behavior of Concrete Pile–Cemented Soil Interface Considering Thermal–Temporal Effect: Experimental Study and Constitutive Modeling Based on Disturbed State Concept.

The bond–slip behavior of concrete pile–cemented soil interface is crucial for load transfer analysis of stiffened deep cement mixing piles, which is greatly influenced by ground temperature and age during long-term curing. However, the thermal–temporal effect on the frictional characteristics of this interface remains unclear. In this paper, an element-scale specimen of concrete pile–cemented soil interface was first designed. Then interfacial shear tests were performed on batches of samples subjected to varied curing temperatures (T) and ages (t) to obtain interfacial bond–slip (τ‒s) curves. The test results showed that the interfacial peak shear strength (τu) increased with the growth of T and t. Based on the experimental observations, a strength development model for τu considering the thermal effect was established. Subsequently, a disturbed state concept (DSC)-based constitutive model incorporating the thermal–temporal effect was proposed for the investigated interface. Both prepeak and postpeak stages of the τ‒s curves can be effectively described by the developed DSC model, exhibiting robust performance in fitting and predicting experimental results. Finally, the DSC model was cross-validated by the interfacial τ‒s data sets collected from reported experimental publications. Across all data sets, the coefficient of determination (R2) exceeded 0.9, and the mean absolute percentage error of τu remained below 10% when comparing predictions with measurements, which strongly highlights the generalization capability of the DSC model. [ABSTRACT FROM AUTHOR]