掺入轮胎橡胶颗粒对砂土剪切性状的影响

为有效提高砂土填料的抗剪强度并降低其重度,利用废弃轮胎橡胶颗粒的良好表面摩擦性与低重度特性,将其掺入到砂土填料,形成加筋机制,通过直剪和三轴压缩试验,研究多种掺入比与不同围压条件下砂土剪切性状,对应力-应变特征进行模拟,并提出模型参数.根据实验结果,峰值剪切强度随橡胶颗粒掺入量增加而减小,峰值偏应力或峰值应力比在300～400 kPa围压下随橡胶掺入量增加而减小,在100～200 kPa围压下,基本不变,砂土泊松比受橡胶颗粒掺入量影响,并随主应力发生"弯转".围压小于200 kPa,掺入10%～20%的轮胎橡胶颗粒可提高砂土的抗剪强度,并降低材料重度,砂胶混合材料应力-应变关系可用Duncan-Chang模型模拟.

Effect of scrap tire bead addition on shear behavior of sand

To enhance the shear st rength and reduce the unit weight of sandy f ill mater ials, dispo sed scr apt ire bead w as added to sand. T he t ire bead pr esented relatively high f rict ion and low unit w eig ht , w hichled to the format ion o f reinforced low density mix tures. Direct shear and t riax ial compression test s wereco nducted to observe the effect s of scrap t ire bead additions and conf inements on the shear behavior of thesand. St ress-st rain relat ions w ere observed and simulated. It w as found that peak shear st reng th decreasedalong w ith incr eased bead addit ion, w hereas conf inement s enhanced the peak shear st rengths of mater ials.Peak deviators or peak st ress rat ios w er e inf luenced by bead addit ions mor e clearly under hig h conf inements than under low conf inement s. Poissonøs rat io s w ere associated w ith the bead addit ions and the pr incipalst resses. Tire bead addit ions o f 10-20% enhanced sand shear st reng th under co nf inement s equal to orless than 200 kPa. The st ress-st rain relat io nship of the mixtures can be mo deled by using Duncan-Chang elastic no nlinear co nstitutiv e law .