粗粒土是一种天然填筑材料,在工程中应用广泛。大量学者对加筋粗粒土的力学性质进行了研究,但对直剪过程中颗粒破碎特性尚无人研究。本文采用大型直剪仪,对粗粒土和加筋粗粒土进行了直剪试验研究,研究了其直剪力学行为与直剪过程中的颗粒破碎特性。试验结果表明:粒径和垂直压力越大,峰值强度越大;加筋后,黏聚力均大幅提高,而内摩擦角有一定程度的减小,黏聚力和内摩擦角均随着粒径的增大而增大;土工格栅除了受到与土的摩擦力外,还受到土体对横肋的阻挡力,阻挡力大幅提高了黏聚力;由不同方法计算得到的颗粒破碎率均随着垂直压力的增大而增大。垂直压力越大,颗粒间的接触越紧密,相互作用越剧烈,破碎率越大。同时在相同垂直压力下粒径越大,破碎越严重。加筋后颗粒破碎率显著降低,加筋可以有效防止颗粒破碎。 Coarse grained soil is a natural filling material, widely used in engineering. A large number of scholars have studied the mechanical properties of the reinforced coarse grained soil. However, no research has been done on the grain breaking characteristics in the direct shear process. In this paper, a large direct shear device, the coarse grained soil and reinforced coarse grained soil were subjected to direct shear test study of its direct shear mechanics behavior and particle shear characteristics in the process of direct shear. The results show that the larger the particle diameter and the vertical pressure are, the greater the peak strength is. After the reinforcement, the cohesion increases greatly, but the internal friction angle decreases to a certain extent. The cohesion and internal friction angle follow the grain In addition to the friction with the soil, the geogrid is also obstructed by the soil against the transverse ribs, and the blocking force significantly increases the cohesion. The average particle breakage rates calculated by different methods are As the vertical pressure increases. The greater the vertical pressure, the closer the contact between the particles, the more intense the interaction, the greater the rate of fragmentation. At the same time under the same vertical pressure, the larger the particle size, the more severe the fracture. Reinforced grain breakage rate significantly reduced, reinforced can effectively prevent the particles broken.