Influence of aggregate particle size on fracture behavior and energy evolution of cemented rockfill in the post-peak stage

Abstract

Cemented rockfill (CRF) combines structural support with sustainable reuse of coal-derived solid waste. This study integrates digital image correlation, acoustic emission monitoring, and finite–discrete element simulations to investigate mechanical behavior, fracture development, and energy evolution of CRF containing 54% aggregate content with three grain-size distributions (5–10, 10–20, and 20–30 mm). Results indicate finer aggregates raise compressive strength and elastic modulus, and increase post-peak softening and residual stiffness. Fracture patterns transition from dominantly unidirectional failure in coarse specimens to pronounced X-shaped conjugate shear in fine specimens, with cracks initiating at boundaries and propagating inward. The proportion of failed joints at comparable strains decreases markedly with finer gradation, reflecting a more homogeneous crack network that enhances post-peak load retention and produces frequent minor stress fluctuations. Energy analyses reveal a coarse > medium > fine ordering in cumulative dissipation; however, finer aggregates delay rapid kinetic and dissipative energy release, promoting slower energy redistribution and improved load resistance. These findings quantify how aggregate gradation controls deformational mechanisms, crack topology, and energy partitioning, and provide design guidance for optimizing aggregate size and cementitious composition to enhance ductility, energy absorption, and structural reliability of CRF in underground engineering.

Keywords

Cemented rockfill (CRF) / Aggregate particle size / Post-peak bearing characteristics / Crack propagation / Energy evolution

CRediT authorship contribution statement

Zhu Li: Writing – original draft, Investigation, Formal analysis, Data curation. Weibing Zhu: Writing – original draft, Validation, Supervision, Project administration. Qingdong Qu: Writing – review & editing, Supervision. Jialin Xu: Writing – review & editing, Project administration. Guorui Feng: Writing – review & editing, Funding acquisition. Chunlei Guo: Investigation, Data curation. Jingmin Xu: Writing – review & editing, Supervision, Funding acquisition, Formal analysis.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgement

This research has received funding from the National Natural Science Foundation of China (Nos. 52478389 and 52525401).

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