Investigation of the Effects of Micro-Parameters on Macro properties of cemented soils by Discrete Element Method

One of the bonded contact models that is used to simulate the cemented bonds formed between soil particles in a cemented sample in the discrete element method is the "flat joint" model. There are numerous microparameters required to define this contact model between particles in modelling and the effects of each of these parameters on the material response are not clear. In this research, after performing large-scale static and dynamic triaxial tests on cemented gravel in the laboratory, they were simulated as a granular assembly in which the flat joint contact model exists at all grain-grain contacts. Then, a sensitivity analysis was conducted to determine the effect of each micro-parameter on the macroscopic response of cemented samples and to specify the most impressive micro-parameters in order to simplify the calibration process. To quantify the relationships between the micro-parameters and the mechanical properties of the sample, regression analysis of the numerical results was performed. The results show that maximum and residual shear strength of sample are mainly dependent on the flat joint cohesion and stiffness ratio. The effects of elastic modulus and stiffness ratio on the initial tangential modulus and shear modulus are significant. The Poisson ratio is affected by the flat join cohesion and stiffness ratio. The damping ratio depends more on the elastic modulus. These results can be used as a guide for modeling the behavior of brittle materials in the discrete element method. A comparison between numerical and experimental tests results of cemented granular specimens revealed that the model was able to capture the softening behavior of these materials with good accuracy.