摘要
橡胶砂作为一种新型廉价的材料,常被用作路基、挡墙等的填料,然而鲜有研究涉及其在双向循环荷载作用下的动力学特性。采用大型动态直剪仪对不同胶-砂粒径比的橡胶砂进行了一系列双向循环荷载作用下的直剪试验,研究了粒径比、法向循环荷载幅值、水平剪切频率对橡胶砂剪切特性的影响。研究结果表明:法向循环荷载作用下,橡胶砂的循环峰值剪切应力随粒径比的增大而增大,最终剪缩量随着粒径比的增大而减小;在剪切应力上,大粒径比的橡胶砂对法向循环荷载幅值的变化更加敏感,且随着法向循环荷载幅值的增大,大粒径比的橡胶砂剪胀更明显;在不同的水平剪切频率下,试样的剪切应力随剪切时间呈不同形式的周期性变化,最大循环剪切应力随水平剪切频率的增大而减小;橡胶砂的剪切刚度和阻尼比均与粒径比呈正相关,即大粒径比的橡胶砂更能提高路基在循环荷载作用下的稳定性。
As a novel and inexpensive material,rubber-sand mixture is commonly utilized as filler in road base and retaining wall.However,limited research has been conducted on its dynamic mechanical properties under bi-directional cyclic loading.A series of direct shear tests was conducted on rubber-sand mixture with different rubber-sand particle size ratios using a large dynamic direct shear instrument to investigate the effects of particle size ratio,normal cyclic load amplitude and horizontal shear load frequency on the shear properties of rubber-sand mixture.The findings indicate that the cyclic peak shear stress of rubber-sand mixture under normal cyclic loading increases with increasing particle size ratio,while the final shear shrinkage decreases with a higher particle size ratio.In terms of shear stress,rubber-sand mixture with large particle size ratio exhibit greater sensitivity to the change of normal cyclic loading amplitude compared to those with small particle size ratio.Moreover,the shear swelling of rubber-sand mixture with large particle size ratio becomes more pronounced with increasing normal cyclic loading amplitude.Additionally,at different horizontal shear frequencies,the shear stress of the specimens display different forms of cyclic changes over shear time,with the maximum cyclic shear stress decreasing as horizontal shear frequency increases.The shear stiffness and damping ratio of the rubber-sand mixture are positively correlated with the particle size ratio,indicating that the rubber-sand mixture with a higher particle size ratio is more capable of improving the stability of roadbed under cyclic loading.
作者
张大伟
李昊泽
刘飞禹
冯忞
ZHANG Da-wei;LI Hao-ze;LIU Fei-yu;FENG Min(Shanghai Pudong Architectural Design and Research Institute Co.,Ltd.,Shanghai 201206,China;School of Mechanics and Engineering Science,Shanghai University,Shanghai 200444,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2024年第S01期239-247,共9页
Rock and Soil Mechanics
基金
国家自然科学基金(No.52378355,No.52078285)
关键词
橡胶砂
循环直剪试验
阻尼比
剪切刚度
rubber-sand mixture
cyclic direct shear test
damping ratio
shear stiffness
