交通荷载与冻融作用下黄土累积变形研究

Study on Cumulative Deformation of Loess under Traffic Loads and Freeze-thaw

为揭示季节性冻土区路基黄土在循环交通荷载和冻融作用下的累积应变特性,进行循环加载试验,探讨冻融循环次数、含水率、动应力幅值、振动频率对冻融后黄土累积塑性应变的影响。结果表明,在试验条件范围内土体并未破坏,产生的累积变形较小且累积应变曲线皆表现为稳定型;循环荷载作用下产生的累积应变随冻融循环次数、含水率、动应力幅值的增加而增大,随振动频率的增加而减小。根据试验结果,提出了考虑冻融循环次数的累积应变指数双曲函数预测模型,并利用试验数据验证了模型的合理性。研究结果可为季节性冻土区路基黄土的沉降预测提供参考。

In order to reveal the cumulative strain characteristics of subgrade loess in seasonal permafrost area under cyclic traffic loads and freeze-thaw action,a cyclic loading experiment is carried out to explore the effects of freeze-thaw cycle times,moisture content,dynamic stress amplitude and loading frequency on the cumulative plastic strain of loess after freeze-thawing.The results show that,(a)the soil mass is not damaged within the test conditions,the cumulative deformation is smaller,and the cumulative strain curve is stable;and(b)the cumulative strain generated under cyclic load increases with the increase of freeze-thaw times,moisture content and dynamic stress amplitude,and decreases with the increase of loading frequency.According to the experimental results,a prediction model of the cumulative strain index hyperbolic function considering freeze-thaw cycle times is proposed,and the rationality of the model is verified by using the experimental data.The results can provide a reference for the settlement prediction of subgrade loess in seasonal permafrost areas.