构造宏观力学与细观力学的联结，一直是岩土力学领域研究课题的热点。从宏、细观两个角度出发，利用颗粒流软件PFC^2D模拟直剪试验，对直剪试验各阶段进行分析，利用风玫瑰图描述力链的方向，综合试验、离散元颗粒流模拟和细观理论对直剪试验的力链分布变化及演化规律进行研究。结果表明，室内试验、数值模拟试验二者结果基本一致；剪切应力达到峰值前内部力链结构有规律地重构，强力链逐渐靠向角平分线；剪切应力达到峰值与水平方向呈接近45°夹角，在卸荷失稳阶段，弱力链重新分布，部分强力链转化而消散，绝大多数保留在剪切带周边。该研究可以更好地理解土体的细观力学机理，为相关数值模拟试验提供参考依据。

The connection between macro-mechanics and meso-mechanics is always a hot topic in the field of geotechnical mechanics. Flow software PFC^2D was used to simulate the direct shear test from the macro-meso-view, and each stage of the direct shear test was carried out. The direction of the force chain was described by the wind rose diagram. A comprehensive test was carried out by discrete element particle flow simulation and meso-view theory. The distribution change and evolution law of the force chain in the direct shear test were studied. The results show that the results of the indoor test and numerical simulation test are consistent. Before the shear stress reaches the peak value, the internal force chain structure is reconstructed regularly, and the strength chain gradually leans against the angular bisector. When the shear stress reaches its peak value, the angle between the shear stress and the horizontal direction is close to 45°. In the stage of unloading instability, the weak force chain will redistribute, some of the strong force chains will transform and dissipate, and most of them will remain around the shear band. This study can better understand the meso-mechanical mechanism of soil and provide reference for related numerical simulation tests.