Abstract: To deepen understanding of the mechanical properties of silica sand particles under impact loading, and enhance the theoretical foundation for the application of silica sand in energy dissipation in protective engineering, an improved split Hopkinson pressure bar (SHPB) apparatus was used to investigate the propagation law of stress waves, particle breakage behavior, and energy absorption effect of silica sand under medium and high strain rates. Results indicate that the velocity of stress waves in silica sand is directly proportional to the particle size, while the peak stress propagation speed exhibits a linear negative correlation with particle size. Additionally, the attenuation capacity of silica sand to stress waves increases with the increase of particle size, showing a linear relationship. Large-sized particles are more prone to fracture under impact, which can effectively increase the degree of energy dissipation. The particles after crushing exhibit a clear fractal distribution pattern, and the fractal dimension shows a good linear correlation with the crushing rate. According to the energy absorption efficiency characteristics of silica sand, under the same stress level, larger particles show higher energy absorption efficiency; under the same strain level, smaller particles demonstrate stronger energy absorption efficiency due to their lower compressibility. In practical engineering, larger particles are recommended to improve energy absorption efficiency, while smaller sizes are preferable when controlling deformation or enhancing stability is required.

Key words: geotechnical engineering; highway engineering; silica sand; split Hopkinson pressure bar (SHPB); crushing characteristics; energy dissipation; dynamic response

摘要： 为深入理解硅砂颗粒在冲击荷载下的力学特性，提升硅砂在防护工程中消能应用的理论基础，采用改进的分离式霍普金森杆（split Hopkinson pressure bar，SHPB）装置，研究了硅砂在中高应变率条件下应力波的传播规律、颗粒破碎行为和吸能效应。结果表明，硅砂中应力波波速与颗粒粒径成正比，而峰值应力传播速度与颗粒粒径呈线性负相关。此外，硅砂对应力波的衰减能力随粒径增大而增大，并表现出线性关系; 大粒径颗粒在冲击过程中更易破碎，进而可以有效增加能量的耗散程度。破碎后的颗粒呈明显的分形分布规律，分形维数与破碎率呈良好线性相关性；根据硅砂吸能效率特性，相同应力水平下，大粒径颗粒具备更高的吸能效率；相同应变水平下，小粒径颗粒因压缩性更低，能量吸收效率更强。实际工程中，若需要提高吸能效率，建议采用较大粒径的硅砂颗粒，在需要控制变形或提高材料稳定性的情况下，选择较小粒径的颗粒更为合适。

关键词: 岩土工程；道路工程；硅砂；分离式霍普金森杆；破碎特征；能量耗散；动力响应