| 赵治海,盛云鸥,刘冲.碎石土单剪力学特性的宏-细观探究[J].矿产勘查,2026,17(4):722-733 |
| 碎石土单剪力学特性的宏-细观探究 |
| Macro-fine view investigation of single shear mechanical properties of gravelly soils |
| 投稿时间：2024-08-04 |
| DOI：10.20008/j.kckc.202604014 |
| 中文关键词: 含碎石黏性土 单剪试验 PFC3D 力学特性 细观结构 |
| 英文关键词: clastic soil with gravel direct shear test PFC3D mechanical properties microstructure |
| 基金项目:本文受陕西省科技统筹创新工程计划项目(2014KTDZ03-01)资助。 |
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| 中文摘要: |
| 探索碎石土的力学特性对保障基础设施建设的安全性和可靠性至关重要。目前对碎石土力学特性的研究主要集中在小尺寸试样的宏观尺度方面，对大尺寸试样的宏-细观特性开展精确测试的研究鲜有报道。本文以碎石土的单剪力学特性为目标，利用自行研制的叠环式单剪仪开展了系列大尺寸碎石土的单剪试验和三维激光扫描试验，研究不同含水率、荷载作用下碎石土的强度特性及剪切破坏面形态，结合颗粒流数值试验揭示了单剪作用下碎石土剪切行为的物理机制；研究结果表明，碎石土的单剪强度随着含水率的增大而减小，随着上覆荷载的增大而增大，主要归因于荷载改变了碎石颗粒的棱角，含水率改变了碎石土颗粒之间的润滑程度。发现了碎石土剪切破坏面分形维数随着含水率以及荷载的增大而增大，且其抗剪强度随其剪切破坏面分形维数成负相关。在此基础上，结合碎石土细观尺度中力链的分布规律，揭示了碎石土剪切行为的“咬合”物理机制。该研究结果以期为碎石土的力学行为提供新的视角，为相关工程设计及建设提供理论基础。 |
| 英文摘要: |
| Exploring the mechanical properties of gravelly soils is essential for ensuring the safety and reliabil.ity of infrastructure construction. Currently, research on the mechanical properties of gravel soil primarily focuseson the macroscopic scale of small-sized specimens, with limited studies addressing the precise testing of both mac.roscopic and microscopic properties of large-sized specimens. This paper targets the single shear mechanical prop.erties of gravel soil, conducting a series of single shear tests and three-dimensional laser scanning tests on large-sized gravel soil using a self-developed stacked-ring single shear instrument. The study investigates the strengthproperties and shear damage surface morphology of gravel soil under varying water content and load conditions,while integrating numerical tests of particle flow to elucidate the physical mechanisms underlying the shear behav.ior of gravel soil in the context of single-shear shoulder action. The findings indicate that the single shear strengthof gravel soil increases with both higher water content and increased load. Notably, the results reveal that singleshear strength diminishes with rising water content but enhances with greater overlying load, primarily due to the in.fluence of load on the angularity of gravel particles and the effect of water content on the lubrication between gravelsoil particles. It was found that the fractal dimension of the shear damage surface of gravel soil increases with the in.crease of water content as well as load, and its shear strength is negatively correlated with its fractal dimension ofthe shear damage surface. On this basis, the physical mechanism of "occlusion" in the shear behavior of gravel soilis proposed to be revealed by combining with the distribution law of the force chain in the fine scale of gravel soil.The results of this study are expected to provide a new perspective on the mechanical behavior of gravel soil and atheoretical basis for related engineering design and construction. |
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