Reinforcing calcareous sands with geogrids is a potentially effective method for large-scale geotechnical constructions in coastal lands. The breakable nature of polygonal calcareous sands determines the complex particle-geogrid interactions. A three-dimensional numerical model of geogrid reinforced calcareous sand (GRCS) was established to investigate the potential mechanical laws based on the discrete element method (DEM), and the reasonableness of the numerical model was verified by comparing with the indoor triaxial test. It follows that the macro-microscopic mechanical behavior of GRCS under the influence of aperture size and tensile resistance of geogrids was further investigated via effective DEM simulations. The presented results show that the decreased aperture size and increased tensile resistance are beneficial to enhance the macro-mechanical properties of GRCS, including strength, internal friction angle and pseudo cohesion. Particle crushing is mainly affected by shear strain and confining pressure. The bulging deformation of GRCS is partially suppressed due to the confining effect of geogrids. Besides, the source of strength enhancement of GRCS is revealed based on the microscopic particle-geogrid interactions, and the calculation method of horizontal and vertical additional stresses in the reinforced soil element considering the effects of tensile resistance and aperture size is further established.

中文翻译：

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三轴荷载作用下土工格栅加筋钙质砂的宏观微观力学行为：孔径尺寸和抗拉力的影响

用土工格栅加固钙质砂是沿海地区大规模岩土工程建设的一种潜在有效方法。多边形钙质砂的易碎性质决定了复杂的颗粒-土工格栅相互作用。基于离散元法（DEM）建立了土工格栅加筋钙质砂（GRCS）三维数值模型，研究其潜在力学规律，并通过与室内三轴试验的对比验证了数值模型的合理性。由此可见，通过有效的 DEM 模拟，进一步研究了土工格栅孔径尺寸和拉伸阻力影响下 GRCS 的宏观微观力学行为。研究结果表明，孔径尺寸的减小和拉伸阻力的增加有利于增强GRCS的宏观力学性能，包括强度、内摩擦角和伪粘聚力。颗粒破碎主要受剪切应变和围压的影响。由于土工格栅的围限作用，GRCS的凸出变形得到部分抑制。此外，基于微观颗粒-土工格栅相互作用揭示了GRCS的强度增强来源，并进一步建立了考虑抗拉力和孔径尺寸影响的加筋土单元水平和垂直附加应力的计算方法。