In this study, a combined finite difference method and discrete element method approach is utilized to establish flexible boundary conditions, and the particle breakage criterion of BPM is adopted to achieve particle breakage. By simulating test results of rockfill materials, the microscopic parameters of these materials are determined. Furthermore, the study investigates the mechanical behavior of rockfill materials under various initial densities and confining pressures from both macroscopic and microscopic perspectives. The findings indicate that at identical densities, the impact of particle breakage on the mechanical behavior of the specimen under low confining pressure is minimal. However, under high confining pressure, the peak stress of the specimen post-breakage decreases, and the occurrence of shear shrinkage becomes more pronounced. At the same confining pressure, specimens experiencing particle breakage at higher densities show an increase in peak stress, while the shear expansion of specimens at lower densities is mitigated. Under the effects of particle breakage, the critical state line on the p′−q curve remains unchanged, whereas the critical state line on the <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$e - (p^{\prime}/p_{a} )^{\zeta }$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>e</mi> <mo>-</mo> <msup> <mrow> <mo stretchy="false">(</mo> <msup> <mi>p</mi> <mo>′</mo> </msup> <mo stretchy="false">/</mo> <msub> <mi>p</mi> <mi>a</mi> </msub> <mo stretchy="false">)</mo> </mrow> <mi>ζ</mi> </msup> </mrow> </math></EquationSource> </InlineEquation> curve shifts downward. The critical state equation is refined by the offset amount Δeb, and a hyperbolic functional relationship between breakage energy and plastic work is established. This forms the foundation for further refinement of the intrinsic model. Through examining the energy conversion mechanism during shear and the evolution of representative microscopic mechanical indicators (e.g., shear band, contact force chain, and coordination number), the inherent macroscopic–microscopic correlation underlying the critical state behavior is explored.

Research on the effect law and microscopic mechanism of particle breakage on rockfill materials

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发表日期：

2025年6月30日

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Yunchao Cui,
Lingkai Zhang,
Chong Shi,
Runhan Zhang,
Rongxian Yang

摘要

In this study, a combined finite difference method and discrete element method approach is utilized to establish flexible boundary conditions, and the particle breakage criterion of BPM is adopted to achieve particle breakage. By simulating test results of rockfill materials, the microscopic parameters of these materials are determined. Furthermore, the study investigates the mechanical behavior of rockfill materials under various initial densities and confining pressures from both macroscopic and microscopic perspectives. The findings indicate that at identical densities, the impact of particle breakage on the mechanical behavior of the specimen under low confining pressure is minimal. However, under high confining pressure, the peak stress of the specimen post-breakage decreases, and the occurrence of shear shrinkage becomes more pronounced. At the same confining pressure, specimens experiencing particle breakage at higher densities show an increase in peak stress, while the shear expansion of specimens at lower densities is mitigated. Under the effects of particle breakage, the critical state line on the p′−q curve remains unchanged, whereas the critical state line on the $e - (p^{\prime}/p_{a} )^{\zeta }$ $e - {(p^{'} / p_{a})}^{ζ}$ curve shifts downward. The critical state equation is refined by the offset amount Δe^b, and a hyperbolic functional relationship between breakage energy and plastic work is established. This forms the foundation for further refinement of the intrinsic model. Through examining the energy conversion mechanism during shear and the evolution of representative microscopic mechanical indicators (e.g., shear band, contact force chain, and coordination number), the inherent macroscopic–microscopic correlation underlying the critical state behavior is explored.