橡胶砂动剪模量和阻尼比循环单剪试验研究

Evaluation of dynamic shear modulus and damping ratio of rubber-sand mixture based on cyclic simple shear tests

对7种不同配比的橡胶颗粒-砂混合物(简称橡胶砂)进行了循环单剪试验,得出了4种不同竖向固结压力p下不同配比橡胶砂的动剪模量和阻尼比的变化规律。研究表明:同一固结压力下,橡胶颗粒的增多使得应力-应变曲线明显降低,动剪模量衰减,阻尼比和隔震消能能力提高;同一配比下,橡胶砂的应力-应变曲线和动剪模量随固结压力的增大而增大,而阻尼比则随着固结压力的增大略有降低;橡胶颗粒含量的增加,会使得动剪模量归一化G_d /G_(d max)-y_d曲线衰减更早,更有利于橡胶砂的隔震应用;与已有研究的对比分析表明,该试验结果与已有文献的试验结果吻合良好,橡胶砂混合物的动剪模量和阻尼比受试验方法的影响不大。

A series of cyclic simple shear tests was conducted on the rubber-sand mixtures （RSMs） with 7 different rubber contents, under 4 different vertical consolidation pressures （p）. The shear moduli and damping ratios of RSMs are evaluated for different shear strain amplitudes and rubber contents. It is shown that： with the increase of the rubber content of RSM, the stress-strain curves drop significantly at the same consolidation pressure, meanwhile the shear modulus of RSM decreases, and the damping ratio, especially small strain damping, increase significantly; the stress-strain curve and the shear modulus of RSM increase with the increase of consolidation pressure while the damping ratio decreases slightly for RSM with a certain rubber content. Increase of rubber content causes earlier attenuation of the generalizedG_d /G_（d max）-γ_d curve, proving to be more conducive for the applications of RSM as isolation material. The experimental results agree well with the results available in the literature, implying that the type of testing methods influences insignificantly the shear modulus and damping ratio of RSM.