重塑红黏土动剪切模量与阻尼比的共振柱试验

Resonant Column Teston Dynamic Shear Modulus and Damping Ratio of the Remolded Red Clay

在保证路基施工质量的前提下,对重塑红黏土在小应变幅值条件下土体动剪切模量和阻尼比的研究,可作为其是否适宜作高铁地基的判别标准之一。为此,在颗分、液塑限及击实等试验的基础上,对不同围压下标准红黏土试样进行小应变幅值的共振柱试验研究。通过对相关试验数据进行整理,得出了重塑红黏土在小应变条件下动剪切模量和阻尼比的变化规律及其影响因素。利用改进的Davidenkov模型对重塑红黏土动力指标进行了拟合,效果良好。该研究成果可为相关高速铁路路基工程提供基础数据及分析参考。

In order to research the dynamic property of the remoulded red clay under small shear strain amplitude condition,through imposing torsional vibration and changing the driving frequency step by step on the soil column with certain humidity,density and stress conditions,the resonant frequencies of the soil sample were measured.Then by cutting off the driving force,the vibration reduction curves were measured.The test can obtain the variation rules and influence factors of the dynamic shear modulus and damping ratio of the remoulded red clay under small strain condition.The results showed that the dynamic shear modulus of the remoulded red clay is relatively bigger,therefore its ability to resist deformation is relatively stronger.When the dynamic shear strain is small than 1×10-4,the dynamic shear modulus reduce slowly,but when the dynamic shear strain is more than 1×10-4,the dynamic shear modulus reduce rapidly.The damping ratio of the remoulded red clay is relatively smaller,so the stress wave can transfer faster and deeper in the soil and its energy reduction is slower.By using the improved Davidenkov model,the dynamic indexes of the remoulded red clay are fitted and the effect is pretty good.