Metastable loess soils can deform, inducing geological and engineering disasters. Therefore, the behavior of the loess under dynamic load is gaining massive attention from researchers to improve the strength of the soils. Fly ash mixed with loess can improve strength and reduce construction costs and environmental pollution. Moreover, it has strong economic and social benefits. This paper investigates the influence of fly ash on the dynamic properties of the modified loess through a series of dynamic triaxial tests of the fly ash modified loess with different fly ash contents. The treated soil samples were prepared using a static compaction method in both ends and cured for 28 days. The dynamic shear modulus ratio, the damping ratio, and the dynamic residual strain of the modified loess were analyzed. The variation characteristics of the dynamic shear modulus ratio and damping ratio with the dynamic shear strain of the fly ash modified loess were obtained. The effect of fly ash content on the dynamic nonlinear parameters of the modified loess was also investigated. In addition, the relationship between the dynamic residual strain and the fly ash content was discussed. The results show that the dynamic shear modulus ratio of fly ash modified loess decreases nonlinearly with the increase in the dynamic shear strain. However, the attenuation rate difference of the curves is small. The damping ratio increases gradually with increasing dynamic shear strain. Under a certain dynamic shear strain level, the damping ratio decreases with the increase in the fly ash content. The dynamic residual strain increases with the increase in the dynamic stress. However, it decreases with the increase in the fly ash content. When the fly ash content is between 10% and 20%, the dynamic residual strain of fly ash modified loess is reduced rapidly. However, when the fly ash content exceeds 20%, the dynamic residual strain decreases slowly. The fly ash content of 20% could be suggested as an optimal content for seismic resistance of the loess foundation.

中文翻译：

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粉煤灰改性黄土的动态非线性和残余变形行为

亚稳态黄土会变形，引发地质和工程灾害。因此，动态荷载作用下黄土的行为越来越受到研究人员的广泛关注，以提高土壤的强度。粉煤灰与黄土混合可提高强度，降低施工成本和环境污染。并且具有很强的经济效益和社会效益。本文通过对不同粉煤灰含量的粉煤灰改性黄土进行一系列动态三轴试验，研究粉煤灰对改性黄土动力特性的影响。处理后的土样采用两端静压法制备，固化28天。分析了改良黄土的动剪切模量比、阻尼比和动残余应变。得到了粉煤灰改性黄土动剪模量比和阻尼比随动剪应变的变化特征。还研究了粉煤灰含量对改性黄土动态非线性参数的影响。此外，还讨论了动态残余应变与粉煤灰含量之间的关系。结果表明，粉煤灰改性黄土的动态剪切模量比随着动态剪切应变的增加呈非线性减小。但是，曲线的衰减率差异很小。阻尼比随着动态剪切应变的增加而逐渐增加。在一定的动态剪应变水平下，阻尼比随着粉煤灰含量的增加而减小。动态残余应变随着动态应力的增加而增加。但随着粉煤灰含量的增加而降低。当粉煤灰含量在10%～20%之间时，粉煤灰改性黄土的动态残余应变迅速降低。但当粉煤灰含量超过20%时，动态残余应变下降缓慢。20%的粉煤灰含量可作为黄土地基抗震的最佳含量。