含水率对大应变下橡胶砂动剪模量和阻尼比的影响

橡胶砂作为轻质耗能填料在工程中应用广泛，其含水状态随应用领域及外界因素变化而不同。研究含水率变化对橡胶砂动剪模量和阻尼比的影响，对于其合理应用具有重要意义。利用大型循环单剪试验装置对6种含水率的橡胶砂在3种竖向压力下进行了循环剪切试验，得到了动剪应变幅值在1%～3%范围时，橡胶砂动剪模量和阻尼比随含水率变化的试验现象。结果表明：橡胶颗粒的加入使得纯砂的动剪模量随含水率的衰减受到抑制，当橡胶颗粒含量达到30%时，橡胶砂动剪模量随含水率的增大反而表现出增大的趋势；随着橡胶颗粒含量的增大，橡胶砂阻尼比随含水率的增大表现出衰减的趋势；虽然离散性较大，但含水率对橡胶砂动力特性的影响不可忽略，橡胶砂动剪模量受含水率影响的平均最大变化幅值可达20%，阻尼比受含水率影响的平均绝对变化值接近0.025；在动力特性随含水率的稳定性方面，橡胶颗粒质量含量为20%的橡胶砂表现相对较好。

Influence of water content on dynamic shear modulus and damping ratio of rubber-sand mixture under large strains

Rubber-sand mixture (RSM) has long been recognized as a light energy absorbing material with wide applications in engineering. The moisture content of RSM may vary depending on the application and external conditions. Therefore, it is important to investigate the influence of water content on dynamic shear modulus and damping ratio of RSM for its appropriate application. Shear tests using large-scale cyclic SGI simple shear test apparatus were carried out on RSM with 6 kinds of water content under 3 kinds of vertical pressures. Test results show that RSM dynamic shear modulus and damping ratio vary with water content when the cyclic shear strain amplitude ranges from 1% to 3%. Test results indicate that: The decrease of dynamic shear modulus of pure sand with increase of water content is restrained by adding rubber particles. When the rubber content reaches 30%, the dynamic shear modulus of RSM shows an increasing trend with the increase of water content, which is contrary to the case of pure sand. With the increase of the rubber content, the damping ratio of RSM shows a decreasing trend with the increase of water content. Though dispersion of results is present, the effect of water content on the dynamic characteristics of RSM is significant. Specifically, the average influence of water content on dynamic shear modulus of RSM reaches up to 20%, and the maximum average variation of damping ratio of RSM shows an absolute value 0.025 under the influence of water content. For the stability of dynamic characteristics with water content variation, a rubber mass content of 20% in RSM may be the optimum content.