In cold regions, the permanent settlement of embankment is mainly caused by the repeated freeze-thaw process and long-term repeated train loads. Meanwhile, the critical dynamic stress (σ_dcr) is an important parameter index for determining embankment stability. Therefore, the accumulative permanent deformation evolution and critical dynamic stress of embankment soil subjected to cyclic freeze-thaw were studied using dynamic triaxial tests. Firstly, a numerical model for calculating critical dynamic stress considering the repeated freeze-thaw process was proposed, which shows that the critical dynamic stress of embankment soil rapidly decreases in the first two repeated freeze-thaw cycles, whereas it tends to be stable after the subsequent freeze-thaw process. Next, based on the normalization of the critical dynamic stress, an explicit model for predicting accumulative plastic strain (ε_p) of embankment soil was established. The above model considers freeze-thaw times, repeated dynamic stress amplitude (σ_d), and loading times, in which all material parameters of Qinghai-Tibet silty clay were presented. Thus, the critical dynamic stress and accumulative plastic strain models established in this paper can be applied to judge the embankment stability and predict the embankment settlement induced by train loads in cold regions.

中文翻译：

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循环冻融路堤粉质粘土临界动态应力及累积变形演化

在寒冷地区，路堤的永久沉降主要是由反复冻融过程和长期反复列车荷载引起的。同时，临界动态应力 ( σ _dcr)是确定路堤稳定性的重要参数指标。因此，采用动态三轴试验研究了路堤土在循环冻融作用下的累积永久变形演化和临界动应力。首先，提出了考虑反复冻融过程的临界动应力计算模型，结果表明路堤土的临界动应力在前两次反复冻融循环中迅速降低，而在反复冻融后趋于稳定。随后的冻融过程。接下来，基于临界动态应力的归一化，预测累积塑性应变（ε _p) 的路堤土。上述模型考虑了冻融次数、重复动应力幅 ( σ _d ) 和加载次数，其中呈现了青藏粉质粘土的所有材料参数。因此，本文建立的临界动应力和累积塑性应变模型可用于判断路堤的稳定性，预测寒冷地区列车荷载引起的路堤沉降。