橡胶混合黏土小应变剪切模量特性试验研究

Experimental study on small-strain shear modulus of rubber-clay mixtures

为了研究橡胶混合黏土(混合土)的动变形特性,对不同橡胶掺量、橡胶粒径和围压的混合土开展共振柱试验,分析动剪切模量G和阻尼比λ的发展规律,并基于二元介质模型,提出了表达混合土接触状态的骨架孔隙比e_(sk)计算方法,进一步依托骨架孔隙比e_(sk)对混合土的最大动剪切模量G_(max)进行评价。结果表明:掺入橡胶颗粒后,混合土的G减小,λ增大,且橡胶掺量增大时,混合土的G减小、λ增大;围压增大时,混合土的G增大、λ减小;橡胶粒径增大时,混合土的G增大、λ减小。随着橡胶掺量增大,骨架孔隙比e_(sk)增大,G_(max)降低;在相同橡胶掺量时,随着橡胶粒径的增大,e_(sk)增大,G_(max)升高。在Hardin公式的基础上,基于骨架孔隙比e_(sk)提出了考虑橡胶掺量和橡胶粒径的G_(max)表征模型,该模型具有较好的准确性,可为评价橡胶混合黏土G_(max)提供依据。

In order to study the dynamic deformation characteristics of rubber-clay mixtures,resonance column tests were conducted on mixtures with different rubber contents,rubber particle sizes,and confining pressures.The development patterns of dynamic shear modulus G and damping ratiolwere analyzed.A calculation method for skeleton void ratio e_(sk) expressing the contact state of mixtures was proposed based on the binary medium model.Furthermore,the maximum dynamic shear modulus G_(max) of mixtures was evaluated based on skeleton void ratio e_(sk).The results show that adding rubber particles leads to a decrease in G and increase inl.As the rubber content increases,G decreases andlincreases.Additionally,G increases andldecreases with increasing confining pressure.Moreover,G increases andldecreases with increasing rubber particle diameter.With an increase in rubber content,the skeleton void ratio e_(sk) increases and G_(max) decreases.At the same rubber dosage,as the rubber particle size increases,e_(sk) increases and G_(max) rises.Based on Hardin’s formula,a characterization model of G_(max) considering rubber content and rubber particle size is proposed using skeleton void ratio e_(sk).The model exhibits good accuracy and can serve as a basis for evaluating G_(max) of rubber-clay mixtures.