作为堆石混凝土的核心骨架材料,大粒径堆石粒径形态特征直接影响坝体的力学性能,但现阶段针对大粒径堆石形状特征的研究相对较少。为了探究大粒径堆石形状特征,基于多视角三维重构技术,提出适用于工程现场的大粒径堆石重构方法;在此基础上,在YF工程现场完成72块完整堆石重构,对其形态特征进行研究分析以及不同堆石混凝土工程的对比讨论。结果表明:①提出的堆石重构方法能够有效适用于工程现场,实现了大粒径堆石的快速采集重构;②YF工程堆石宏观形态较为饱满,80%以上堆石的磨圆度>0.63,真球度>0.7,但不同粒径堆石的比表面积存在显著差异;③YF与DZ工程的堆石虽然岩性不同、粒径分布不同,但在宏观形状特征与部分形状参数上取得了较好的一致性。研究成果可为同类型工程的堆石选取、评价、性能研究提供基础形态学参考。

[Objective] Large-sized rockfill forms the primary load-bearing skeleton in rock-filled concrete (RFC), and its morphological characteristics strongly influence the mechanical performance of dam structures. This study develops a practical 3D reconstruction method for large-sized rockfill under field engineering conditions, aiming to reveal the similarities and differences in shape parameters and provide a reliable technical approach and foundational data for the selection, evaluation, and performance optimization of rockfill materials in RFC engineering. [Methods] A multi-view 3D reconstruction technique based on structure from motion (SFM) was employed to acquire and reconstruct the morphological characteristics of large-sized rockfill. The segment anything model (SAM) was employed to isolate rockfill from the background in the images. For morphological analysis, the reconstructed models were imported into Blender software. Based on established particle shape characterization systems, parameters including equivalent particle size, elongation, flatness, roundness, true sphericity, convexity, and maximum projected sphericity were quantified. Following the Zingg scheme, particles were categorized into spherical, platy, bladed, and rod-like forms. Statistical analysis involved cumulative distribution function (CDF) curves to characterize overall parameter trends and box plots to compare parameter distributions across different particle size groups. Additionally, morphological data from the YF project were compared with results from the DZ project reported in existing literature to examine the similarities and differences between projects with different lithologies and particle size distributions. [Results] Analysis of 72 reconstructed specimens from the YF project revealed that the rockfill exhibited a generally blocky and well-rounded macroscopic morphology. Statistical shape classification showed that 45% of the YF rockfill was spherical, 23% was platy, 21% was rod-like, and 11% was bladed. Comparative analysis among different particle size groups within the YF project identified specific surface area as the parameter most sensitive to particle size, displaying a nearly linear monotonic decreasing trend with increasing particle size. Elongation showed a monotonic increase with particle size, while convexity showed a monotonic decrease. The overall distribution patterns of YF (granite) and DZ (limestone) particles in the shape classification were similar between the two projects. The relationships between key parameters, including the power-function correlations between the length-to-width ratio and roundness and between volume and surface area, were also consistent. However, the YF project exhibited a lower proportion of spherical particles and higher proportions of platy, bladed, and rod-like particles, indicating slightly greater shape irregularity and diversity. [Conclusion] (1) The proposed 3D reconstruction methodology for large-sized rockfill under field engineering conditions has been validated effective and practical. (2) The morphological analysis of 72 rockfill specimens from the YF project confirms that the field rockfill is predominantly well-rounded and blocky. While parameters such as roundness and true sphericity show high values with limited sensitivity to particle size, the specific surface area demonstrates clear systematic variation across different size groups. (3) Despite differences in lithology, the rockfill from the YF and DZ projects shows strong consistency in fundamental macroscopic morphological characteristics and the functional relationships between key shape parameters. (4) The shape composition of the YF project rockfill differs from that of the DZ project, with a lower percentage of spherical particles and higher percentages of non-spherical (platy, bladed, and rod-like) particles.