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Experimental Investigation of the Macro‐ and Mesoscale Mechanical Behavior of Rockfill Materials Under the Coupled Effects of Coarse‐Particle Content and Confining Pressure

Year: 2026

Type: article

Abstract: This study investigates the macro‐meso mechanical evolution of dam rockfill under the coupled effects of coarse‐particle content ( P 5 ) and confining pressure ( σ 3 ) using large‐scale triaxial tests and PFC3D simulations. The results show (1) shear strength and particle breakage depend synergistically on σ 3 and P 5 . For example, at P 5 = 38.02%, increasing σ 3 (200–800 kPa) raises Marsal’s breakage index from 3.87% to 8.64%. At a constant σ 3 , increasing P 5 (27.56% to 70.77%) further elevates breakage from 7.41% to 9.12%. (2) Meso‐kinematics quantify the granular skeleton’s transition from a “suspended” to an “interlocking” state. Higher P 5 shifts the displacement field from unilateral eccentric to uniform concentric gradients, shrinking the >12 mm “long‐tail” in probability density and proving that interlocking restrains extreme localized slip. (3) A critical percolation threshold emerges at P 5 = 61.34%, marked by an anomalous rightward shift of the main displacement peak. This reflects global dilatancy induced by particles overriding interlocking resistance, which retracts at P 5 = 70.77% as particle mobility limits lock. (4) Topological reshaping of the contact network dictates microcrack anisotropy. Higher P 5 increases rigid contacts, raising total microcracks by ~6%. Consequently, crack distribution transitions from random to highly anisotropic, aligning with major force chain conjugates. Ultimately, this elucidates the failure mechanism transition from “loose slip failure” to “structural shear dislocation,” providing a scientific basis for assessing high earth‐rock dam stability.

Source: Advances in Civil Engineering

DOI: 10.1155/adce/8071333

Authors: Haoquan Chi, Xu’an Qian, Qian Yu, Fulai Wang, Mingfang Wei, Bin Ou

Institutions: Yunnan Agricultural University, Yunnan Water Conservancy and Hydropower Vocational College

Language: English

Topic: Geotechnical Engineering and Soil Mechanics

Subfield: Civil and Structural Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Industry, innovation and infrastructure

Open Access status: gold

Estimated APC paid: $2,760