Materials, Vol. 18, Pages 1726: Discrete Element Damage Constitutive Model of Loess and Corresponding Parameter Sensitivity Analysis Based on the Bond Rate

Materials doi: 10.3390/ma18081726

Authors:
Hui Qi
Xiaoyan Liu
Haining Wang
Chao Hu

This study introduces a novel discrete element method (DEM) model for compacted loess, incorporating a bond rate parameter within a linear contact bond model to simulate constitutive damage behavior. This enhancement significantly improves the characterization of structural damage from repeated wet–dry cycles, offering a quantitative method for predicting damage progression. Unlike existing DEM models, our model directly uses a bond rate parameter to quantitatively describe inter-particle bond deterioration, reflecting reduced bonding strength due to pore structure development and the weakening effect of water. Rigorous calibration and validation were performed using comparative experiments. A key innovation is the systematic analysis of microscopic parameters (contact stiffness, friction coefficient, contact strength, and bond rate) and their impact on macroscopic mechanical behavior. Our findings show that decreasing the bond rate significantly reduces the macroscopic mechanical properties, providing valuable insights into the micro–macro relationship. We comprehensively evaluated prediction sensitivity to these parameters. This methodology offers a new perspective on using DEM for predicting crucial civil engineering material properties, providing a valuable reference for incorporating bond rate parameters into future modeling, particularly for long-term geotechnical material behavior under environmental degradation. The model’s accurate representation of wet–dry cycle effects on loess strength improves earth structure design and safety.

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