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由于重度小、渗透性强,橡胶粉末常作为边坡、路基和挡土墙的填料,以代替部分砂土,从而提高挡土墙的安全性,并减少砂子的用量。在地震或交通荷载作用下,掺有橡胶粉末的砂土动力学特性,包括应力-应变关系曲线、孔隙水压力累积规律、动剪切模量和抗液化能力方面的研究亟需开展。借助CKC循环动三轴仪,开展饱和不排水条件下掺有橡胶粉末的砂土试样的动力学特性研究,重点评估掺入的橡胶粉末对试样的抗液化性能的影响。研究结果发现,掺有不同粒径橡胶粉末的砂土对应力-应变关系、孔隙水压力的影响非常显著,同时发现,粒径较大的橡胶粉末可以极大地提高试样的抗液化能力。另外,发现掺入量越大,对抗液化能力的提高越明显,且随着掺入量的提高,表现出与常规砂土液化不同的破坏模式。研究结果进一步明确了掺有橡胶粉末的砂土动力特性行为,为橡胶粉末在工程实践中的应用提供了技术依据。最后,对橡胶砂土混合的微观机制进行了解释。
Due to its small weight and high permeability, rubber powder is often used as a filler in slopes, subgrade and retaining walls to replace part of sand so as to improve the safety of retaining walls and reduce the amount of sand used. Under earthquake or traffic load, the research on the dynamic characteristics of sand mixed with rubber powder, including the stress-strain curve, the law of accumulation of pore water pressure, dynamic shear modulus and liquefaction resistance, is urgently needed. With the help of CKC cyclic dynamic triaxial apparatus, the dynamic characteristics of sandy soil samples mixed with rubber powder under undrained saturated conditions were studied, and the influence of the rubber powder incorporated on the liquefaction resistance of the specimens was evaluated. The results show that the influence of stress and strain and pore water pressure on the sand mixed with different particle size rubber powders is very significant. It is also found that the rubber powder with larger particle size can greatly improve the liquefaction resistance of the sample. In addition, it was found that the greater the incorporation, the more obvious the improvement against liquefaction ability, and with the increase of the amount of incorporation, it shows a different failure mode than the conventional liquefaction of sand. The results further clarify the dynamic behavior of sand mixed with rubber powder, which provides a technical basis for the application of rubber powder in engineering practice. Finally, the microscopic mechanism of rubber sand mixing is explained.