| 基于DEM的钙质砂直剪试验：粒径范围与破碎率的率效应研究 |
| DEM-based Direct Shear Test on Calcareous Sand: Study on Rate Effects of Particle Size Range and Breakage Ratio |
| 投稿时间：2025-10-20 修订日期：2025-12-23 |
| DOI： |
| 中文关键词: 钙质砂 离散元 颗粒破碎 直剪试验 力链 |
| 英文关键词:calcareous sand DEM particle breakage direct shear test force chain |
| 基金项目:国家自然科学基金资助项目（42477194）；中国海洋大学优秀青年科技人才培育计划项目（202441008）；山东省高等学校青创科技支持计划（2024KJH119）；中国海洋大学海洋油气勘探国家工程研究中心数据采集技术分中心资助（2025SDAT02） |
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| 中文摘要: |
| 钙质砂的力学行为显著受控于其复杂颗粒形态与破碎特性，而传统球形颗粒模型难以准确模拟此类效应。为克服此局限，本文创新性地建立了基于多球聚合算法与平行粘结模型的可破碎钙质砂三维离散元直剪模型，实现了对真实颗粒形态与破碎行为的精细模拟。系统研究了粒径范围与剪切速率对宏细观力学特性的影响，发现高应力下率敏感性随粒径增大呈先降后增趋势，临界速率由0.005 m/s增至0.04 m/s；细观层面揭示了颗粒破碎率与粒径的正相关性，以及高应力下破碎行为对速率的非单调响应机制。本研究系统地揭示了粒径对钙质砂率效应的影响规律，弥补了现有研究在该条件下的空白，所揭示的细观机理为构建更为完善的钙质砂率效应理论体系提供了重要的数值依据。 |
| 英文摘要: |
| The mechanical behavior of calcareous sand is significantly governed by its complex particle morphology and fragmentation characteristics, which traditional spherical particle models struggle to accurately simulate. To address this limitation, this study innovatively establishes a 3D discrete element direct shear model for crushable calcareous sand based on a multi-sphere aggregation algorithm and a parallel bond model, enabling high-fidelity simulation of realistic particle morphology and crushing behavior. The influence of particle size range and shear rate on macro- and meso-mechanical properties was systematically investigated. Results show that under high normal stress, rate dependence exhibits a decreasing-then-increasing trend with increasing particle size, while the critical shear rate rises from 0.005 m/s to 0.04 m/s. At the meso-level, the study reveals a positive correlation between particle breakage ratio and particle size, along with a non-monotonic response of fragmentation behavior to shear rate under high stress conditions. This work systematically elucidates the influence of particle size on the rate-dependent behavior of calcareous sand, addressing a gap in current research under these specific conditions. The revealed meso-mechanisms provide crucial numerical evidence for constructing a more comprehensive theoretical framework for the rate effects in calcareous sand. |
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