Evaluation of the effect of micro-parameters on the macroscopic properties of cemented granular soils

Document Type : Research Article

Authors

1 Geotechnic-civil engineering-Shahid Beheshti university-Tehran-Iran

2 P.O. 16765-1719 Tehran, Iran

Abstract

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 micro-parameters required to define this contact model between particles in the modeling 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. A regression analysis of the numerical results was performed to quantify the relationships between the micro-parameters and the mechanical properties of the sample. The results show that the maximum and residual shear strength of a 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 test results of cemented granular specimens revealed that the model was able to capture the softening behavior of these materials with good accuracy.

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