基于颗粒接触状态理论的粗细粒混合料液化强度试验研究

Experimental investigation on liquefaction resistance of fine-coarse-grained soil mixtures based on theory of intergrain contact state

为探讨粗细粒混合料的液化强度CRR,对具有不同细粒含量FC和相对密度Dr的粗细粒混合料开展了一系列不排水循环三轴试验。基于颗粒接触状态理论,将粗细粒混合料分为类粗粒土、中间性态土和类细粒土;用骨架孔隙比esk表征混合料骨架颗粒的接触状态,引入参数b与m描述粗细粒混合料从类细粒土到类粗粒土过度中粗粒与细粒对颗粒接触状态的影响。试验结果表明：随着FC的增加,具有相同Dr粗细粒混合料的CRR先降低后基本保持不变。此外,具有不同FC和Dr的粗细粒混合料CRR都随esk的增大而降低。分析表明：基于颗粒接触状态理论的esk是合理地表征粗细粒混合料CRR的一个物理状态指标,且两者呈现较好的负幂函数关系。

In order to investigate the liquefaction resistance CRR of fine-coarse-grained soil mixtures, a series of undrained cyclic triaxial tests are performed on the fine-coarse-grained soil mixtures with different values of fines content FC and relative density Dr. According to the theory of intergrain contact state, the mixtures are categorized as coarse-like soil, intermediate behavior soil and fines-like soil. The skeleton void ratio esk is used as the grain contact density index to describe the intergrain contact state which composes the skeleton of mixtures, and the parameters b and m are used to characterize the contribution of the fines and the coarse grains to the transition between coarse-like and fines-like behaviors in mixtures. The test results show that as FC increases, the CRR of mixtures with the same Dr decreases first, and thereafter it remaines constant. In addition, the CRR of mixtures with different values of FC and Dr decreases with the increase of esk. Moreover, the test data obtained in this study reveal that esk can be used as the index to uniquely evaluate the CRR of mixtures, and a power relationship between a decrease in CRR and an increase in esk is then obtained.