Effects of cementation on the cyclic resistance of granular soils with presence of initial static shear stress

Aoxi Zhang, Chaofa Zhao, Hadrien Rattez, Frédéric Collin

In engineering applications such as non-invasive cementation beneath existing structures or naturally induced cementation around piles, cementation can develop in soils that have previously undergone initial static shear. However, the joint effect of cementation and initial static shear stress on subsequent cyclic loading behaviour remains largely uninvestigated, despite its crucial importance for understanding foundation response to seismic events and cyclic loading conditions. This study investigates the combined effects of cementation and initial static shear stress on the subsequent cyclic behaviour of granular soils using the discrete element method (DEM). First, DEM specimens with varying levels of cementation are subjected to undrained cyclic loading under different cyclic stress ratios (CSR) without initial static shear stress and the results align well with experimental results reported in the literature. Then, the role of initial static shear stress on the undrained cyclic response of the specimens is investigated. The results indicate that the liquefaction resistance of cemented soil depends on both CSR and initial static shear stress. The effect of initial static shear stress, which can be either beneficial or detrimental, is more pronounced at low CSR values. The DEM model developed in this study quantitatively captures actual cementation levels, offering practical guidance for engineering applications such as vibratory extraction of aged piles. Micromechanical analysis reveals that cementation helps maintain structural stability by preventing contact loss between particles, while initial static shear stress accelerates contact degradation and reduces structural stability during cyclic loading. These insights contribute to the development of multiscale constitutive models for cemented soils under cyclic loading conditions.