橡胶颗粒土动剪模量与阻尼比的共振柱试验研究

废旧轮胎橡胶颗粒与砂土组成的橡胶颗粒土相比于纯砂而言,具有密度轻、弹性变形能力强、耗能大、剪切模量低等特点,可广泛应用于边坡、挡土墙和路基回填、桥台跳车治理以及建筑隔震减振等工程领域。通过共振柱试验,重点对比研究了橡胶含量、粒径及围压对混合土动剪切模量和等效阻尼比的影响规律。结果表明,小应变范围内,在围压和粒径相同时,随橡胶含量的增加,橡胶土动剪切模量减小,阻尼比增大,动剪模量比衰退变缓;含量和粒径相同时,围压增大,动剪模量增大,动剪模量比衰退变缓,阻尼比减小。在大应变幅值下,橡胶含量较低时,随着围压增大,动剪模量比衰退明显加快;而当橡胶含量较高时,围压对其影响与小应变范围相同;而围压与橡胶含量相同时,不同橡胶粒径的模量与阻尼比曲线非常接近。橡胶土的动剪模量与阻尼比主要受橡胶含量与固结围压影响,而粒径影响可忽略不计。

Experimental Study on Dynamic Shear Modulus and Damping Ratio of Rubber-sand Mixed Soil

Compared with pure sand, the rubber particles of waste tires and sand mixtures have the characteristics of light density, strong elastic deformation, high energy consumption and low shear modulus. They can be widely used in engineering fields such as slope, retaining wall, roadbed backfilling, abutment traffic jump mitigation, building isolation and vibration reduction. In this paper, the effects of rubber content, particle size and confining pressure on the dynamic shear modulus and equivalent damping ratio of mixed soil are studied by resonance column test. The results show that in the small strain range, the dynamic shear modulus of rubber-sand mixed soil decreases, the damping ratio increases and the dynamic shear modulus ratio declines slowly with the increase of rubber content when the confining pressure and particle size are the same; Under the same content and size conditions, the dynamic shear modulus increases, the dynamic shear modulus reduces slowly and the damping ratio decreases with the rise of confining pressure. Under large strain amplitude, dynamic shear modulus ratio decline speedily with the increase of the confining pressure when the rubber content is low. When the rubber content is high, the influence of the confining pressure is the same as in the small strain range. When the confining pressure and content are the same, the variation curves of modulus and damping ratio with rubber particle size are very close to each other. That is, the dynamic shear modulus and damping ratio of rubber-sand mixed soil are susceptive to rubber content and consolidation confining pressure instead of particle size.