颗粒特性对材料小应变动力特性的影响

Effects of particle characteristics on small-strain dynamic properties of granular materials

土体的小应变剪切模量和阻尼比是表征土体动力学特性的重要参数。针对文献中关于砂土颗粒形状与粒径大小对小应变动力特性的影响仍存在争议,利用能量注入式虚拟质量共振柱,系统测量了特定形状与粒径的聚碳酸酯颗粒试样的小应变剪切模量和阻尼比。试验结果表明,颗粒粒径大小对试样的小应变动力学特性影响不大,而颗粒形状则有显著影响。球形颗粒试样的小应变剪切模量小于椭球颗粒和双球颗粒的试样,而球形颗粒试样的小应变阻尼比大于椭球、双球颗粒试样。椭球和球形颗粒混合试样的小应变剪切模量和阻尼比则处于两种单一颗粒之间。小应变剪切模量与阻尼比均与颗粒综合规则度存在较好的相关性,表明综合规则度可用于表征颗粒形状对材料小应变动力特性的影响。

The small-strain shear modulus and damping ratio are the important dynamic properties of granular soils.Controversial views exist regarding the effects of particle shape and size on the small-strain dynamic properties. In this study,the small-strain shear modulus and damping ratio are measured systematically for the specimens formed by polycarbonate particles with well-controlled particle shape and size using the energy injecting virtual mass resonant column system. The test results show that the particle size has few effects on the small-strain shear modulus and damping ratio, while the particle shape has significant impacts. The shear modulus of the specimens of spherical particles is smaller than that of the elliptical particles and the clumped particles under otherwise similar conditions, while the damping ratio of the specimens of spherical particles is higher than that of the specimens of the other two particles. For the mixtures of spherical and elliptical particles, the small-strain shear modulus and damping ratio are between those of the specimens of each type of particles. The overall regularity,quantifying the shape of the particles, can be used to characterize the small-strain properties of the specimens.