废旧轮胎橡胶颗粒–砂混合料抗剪强度与破坏模式试验研究

Tests on shear strength and failure mode of rubber particle-sand mixtures

由废旧轮胎回收橡胶颗粒与砂混合而成的橡胶-砂混合料具有密度低、变形能力强、阻尼高等诸多优点,将其应用于土木工程,是实现土木工程绿色可持续发展的重要途径之一。通过对橡胶-砂混合料进行固结不排水剪切试验,探讨了橡胶颗粒含量XC、粒径比d50,r/d50,s、相对密实度D_(r)、固结围压σ’_(m)等因素对混合料抗剪性能的影响规律及其机理。研究结果表明:随XC的增加,混合料的破坏模式表现出由部分软化-剪胀向完全硬化-剪缩转变。总体来说,随橡胶颗粒的掺入量增加,混合土体(σ_(1)-σ_(3))f和内摩擦角均出现较明显下降,有效内摩擦角则会出现一定程度的提高,且橡胶粒径与砂越接近影响越明显,而Dr的增加可以显著改善混合料的抗剪强度特性。基于土骨架微观结构,初步解释了试验现象及其规律。

The recycled waste tire rubber particles mixed with sand have the advantages of low density,strong distortion-resistant capacity and high damping.The mixtures are becoming a kind of new geotechnical material,which realizes the sustainable development of civil engineering.In this study,the influence law and mechanism of the rubber content XC,particle size ratio of rubber and sand d50,r/d50,s,relative density D_(r) and confining pressure σ’_(m) on the shear resistance of mixtures are evaluated by a series of consolidated undrained tests.The results show that the failure mode shows a transformation from partial softening-dilatancy to complete hardening-contraction with the increase of XC.In general,the increase of XC will lead to a significant decrease of(σ_(1)-σ_(3))f and the internal friction angle,and an improvement of the effective internal friction angle to a certain extent.The closer the rubber particle size is to the sand,the more obvious the influence is.In addition,the increase of Dr can significantly improve the shear strength characteristics of the mixtures.Based on the micro-soil skeleton structure,the experimental phenomenon and its laws are preliminarily explained.