橡胶黏土混合土动剪切模量及阻尼比试验研究

为了研究橡胶黏土混合土动力特性,将橡胶掺入黏土,在4种围压下对5种不同配比橡胶黏土混合土进行室内动三轴试验以研究橡胶含量及围压对混合土动剪切模量和阻尼比的影响。结果表明,相同围压下,混合土动剪切模量较素土有很大降低,随着橡胶含量的增多而逐渐降低且降低速度由快变慢,动剪切模量与动应变关系曲线非线性特征减弱。阻尼比随着橡胶含量增加逐渐增加,且均较素土有显著提高。相同橡胶含量时,动剪切模量随着围压增大而增大,动剪切模量与动应变关系曲线线性特征增强,阻尼比随围压增大而减小。橡胶黏土动剪切模量与动应变关系可以用H-D模型表示,最大动剪切模量与围压之间的关系可以用线性函数表示,阻尼比与动应变关系可以用修正的陈国兴模型表示。结果证明,橡胶黏土混合土具备较好的隔震减震性能。

Experimental Study on Dynamic Shear Modulus and Damping-Ratio of Rubber-clay Mixture

To illustrate the dynamic characteristics of rubber-clay mixture, laboratory dynamic triaxial tests under 4 different confining pressures were conducted on the rubber-clay mixtures with 5 different rubber contents. The effects of rubber content and confining pressure on shear modulus and damping ratio of rubber-clay mixture were studied. The results show that under the same confining pressure, the dynamic shear modulus of the mixtures is much lower than that of the pure clay. The dynamic shear modulus decreases with the increase of rubber content, and reducing rate gradually slows down. The nonlinear relationship between dynamic shear modulus and dynamic strain fades gradually. The damping ratio increases gradually with the increases of rubber content, and has a remarkable improvement compared with that of pure clay. With same rubber content, the dynamic shear modulus increases and the damping ratio decreases with the increase of confining pressure, and the linear behavior between dynamic shear modulus and dynamic strain strengthens. The relationship between dynamic shear modulus and dynamic strain can be expressed by H-D model. The relationship between maximum dynamic shear modulus and confining pressure can be expressed by a linear function. The relation between damping ratio and dynamic strain can be expressed by the modified Chen Guo-xing model. Test results confirm that earthquake resistant performance of rubber-clay mixture is good.