饱和橡胶砂动力特性动三轴试验研究

Cyclic triaxial tests on dynamic characteristics of saturated rubber-sand mixture

橡胶质轻、耐磨、渗透性好、减振性能优良,橡胶颗粒与砂土混合作为土工填料可被用于边坡、路基和垃圾填埋场中。通过室内动三轴试验研究了不同橡胶含量混合土的动强度特性及动孔压发展特性。结果表明:橡胶质量含量越高,混合土的抗液化强度越高,且混合土的液化强度曲线符合乘幂函数关系;考虑橡胶质量含量的影响,得到了归一化混合土液化强度曲线;初始应力比和橡胶含量对混合土动孔压比发展具有明显影响,建立了不同试验条件下动孔压比发展模型。试验发现,当初始动应力比超过0.4时,10%橡胶含量的混合土出现明显橡胶颗粒向上迁移现象。基于颗粒细观接触和颗粒运动状态,揭示了橡胶颗粒迁移机制。

Due to the advantages in lightness,wear-resistance,permeability and high-damping,the rubber particles are mixed with sand to be applied as the lightweight fillers for slopes,subgrades and retaining walls.Thus,in this paper,the liquefaction potential and the dynamic pore water pressure of saturated rubber-sand mixtures with different rubber contents are investigated through the cyclic triaxial tests.The results show that the resistance to liquefaction significantly increases with the increase of rubber content in the rubber-sand mixtures.In addition,the liquefaction strength curve can be described by a power function.By taking the influence of rubber content,the normalized liquefaction strength curve of rubber-sand is obtained.The evolution models of dynamic pore pressure ratio under different test conditions are established,which are obviously influenced by the initial cyclic stress ratio and rubber content.It is observed that an evident upward migration of rubber particles occurs in the 10%rubber content mixtures when the intitial cyclic stress ratio exceeds 0.4.Based on the mesoscopic contact and movement state of particles,the migration mechanism of rubber particles is revealed.