Fatigue damage model and parameter estimation of cemented sand and gravel material under cyclic loading

Based on the stress-strain relationship under cyclic loading by large dynamic triaxial test, the cumulative strain distribution law of CSG materials was studied, and a dynamic damage model of CSG material was established by determining reasonable dynamic damage variables, the physical meaning and the values range for CSG material of this mode parameters were studied, too. The results show that the relationship curve between damage variable and cycle number of CSG material under cyclic loading is inverted S-type, which can be divided into three stages, and similar to the distribution law of cumulative strain. The three stages are corresponding to the closure of original defects, the initiation and propagation of new cracks, and the unstable propagation. According to the value of the damage development factors of the CSG material in the damage model, the fatigue life of CSG material under cyclic loading can be determined.

Automated summary

Based on large dynamic triaxial tests, a dynamic damage model for CSG material was established to study the relationship between damage variables and cycle number under cyclic loading. The model shows an inverted S-shaped curve with three stages corresponding to original defect closure, crack initiation and propagation, and unstable propagation, which can determine the fatigue life of CSG material.