Mesoscopic damage mechanism of multiple freeze–thaw cycles of cement gravel based on particle flow theory

Currently, most experts only focus on the surface failure characteristics of material structures. Moreover, previous damage constitutive models were unable to simulate the nonlinear deformation characteristics of cement crushed stone during the initial compaction stage. To study the microdamage of cement crushed stone after freeze–thaw cycles and uniaxial compression, further exploration was conducted on the changes in displacement, number of microcracks, relationship between acoustic emission events and microcrack development after freeze–thaw cement gravel loading, as well as the number of force chains before and after loading. Based on the theory of damage mechanics, this article establishes a damage constitutive model that can simulate the entire deformation process of cement crushed stone under uniaxial compression conditions using a particle flow program. Based on the numerical model created by the discrete element method, this article reproduces the entire process of internal fracture of cement crushed stone from a microscopic perspective, which has certain advantages in studying the complex mechanical behavior of cement crushed stone. After freeze–thaw treatment, irreversible damage occurs inside the cement-stabilized crushed stone. The more freeze–thaw cycles, the lower the compressive strength of cement-stabilized crushed stone.