轮胎颗粒混合土动力特性参数影响规律试验研究

Dynamic properties variation of tire shred-soil mixtures

废旧轮胎碎片颗粒与砂土混合用作路基或挡墙填料、建筑物基础隔震体系等具有质轻、土压力小、减震隔振效果好、耐久性优良、费用低廉的特点。通过室内数字化动三轴试验，重点对比研究了废旧轮胎颗粒含量及围压对混合土及纯砂土动强度、动弹性模量和等效阻尼比等主要动力特性参数的影响规律。结果表明，在相同围压和动剪应力比条件下，混合土动强度相对纯砂土略有降低（最大降低量约20 kPa，即约8%）；所有配比混合土动弹性模量均小于纯砂，且减小效果显著，最大减小量约22 MPa（即约60%）；混合土等效阻尼比先随轮胎颗粒含量的增大而增加，之后又随之减小，临界含量值介于30%～40%之间，混合土等效阻尼比相对纯砂土最大增加量约91%。结果证实，混合土剪切刚度有效降低，可以发挥减震隔振的优势。

Sand soil mixed with waste tire shreds can be used as filling of subgrade, retaining wall or shock isolation system of base etc., which has many advantages, such as small earth pressure, good absorption of vibration, excellent durability and low cost. There are comparison between the mixture and the sand soil through digital dynamic triaxial tests, which mainly include the influence of the tire shred content and the confining pressure on the dynamic strength, dynamic elastic modulus and equivalent damping ratio. The results show that when the confining pressure and the dynamic shear stress ratio are equal, the dynamic strength of the mixture is slightly lower than that of the sand soil which is reduced by 20 kPa, 8%. The dynamic elastic modulus of the mixture obviously decreases with 22 MPa, 60%of the maximum reduction. The equivalent damping ratio of the mixture firstly increases, then decreases with the increasing of the tire shred content;the critical tire shred content is about 30%-40%. The mixture’s maximum increment of equivalent damping ratio is about 91%. Test results confirm that the shearing rigidity of the mixture can effectively reduce, which can exploit the advantage of the absorption of vibration to the full.