考虑应力历史的冻土一维蠕变模型

1D creep model for frozen soil taking account of stress history

受力历史是影响冻土力学行为的关键因素。引入融土中考虑应力历史的一维蠕变模型并进行了相应修正,使其能够反应温度对冻土蠕变特性的影响,通过不同温度条件下的K_0加载试验获取相关模型参数,经过回归分析得到了各参数与温度的函数关系。通过对比试验和模型计算结果表明,修正后得到的冻土一维蠕变模型在预测不同温度条件下土体的蠕变发展规律时具有较好的预测精度。同时,随着施加压力的增大,该模型能够准确描述当外压力超过其历史上所受最大压力时所产生的应变急剧增长现象。因此,该模型可以作为寒区工程稳定性分析和设计的可靠依据。

The stress history is a key factor influencing the mechanical behavior of frozen soil. A one-dimensional creep model for unfrozen soil considering the effect of stress history is modified to describe the creep behavior of frozen soil. Model parameters are obtained from K0 tests under different temperatures. Through the regression analysis, the relationships between model parameters and temperatures are established. The comparison between the calculated and tested results indicates that the modified creep model has a good agreement with the experimental results under different temperatures. At the same time, with the increase of overloading, this model can describe the sharp change of strain when the overloading is larger than the historical largest applied stress reasonably. So, the modified model can be a useful tool for the stability analysis and design of prosects in cold regions.