高温冻土的蠕变特性试验及蠕变模型研究

为了研究高温冻土蠕变变形特征以及各影响因素对蠕变的作用， 分别在含水量15%、 25%及35%， 荷载100 kPa、 200 kPa及300 kPa， 温度-1.5 ℃、 -0.7 ℃及-0.3 ℃的条件下开展了室内单轴蠕变试验， 分析在无侧限条件下高温冻土在不同温度、 荷载及含冰量条件下的蠕变变形特性。结果表明： 在当前试验条件下， 冻土蠕变变形非常可观， 且蠕变曲线都没有出现渐进流阶段； 温度是影响冻土蠕变的最重要的外在因素， 而含冰量是影响冻土蠕变的关键内在因素； 在高含冰量条件下温度及荷载的改变对蠕变速率的影响非常显著， 甚至引起量级上的差别。在现有试验条件下， 高温冻土蠕变过程可利用Burgers黏弹性模型来较好地描述。

Study on creep test and creep model of warm frozen soil

In order to investigate the creep deformation behavior of warm frozen soil and its relationship with various influencing factors， uniaxial creep tests were carried out in laboratory on the specimens with moisture contents of 15%， 25% and 35%， load levels of 100 kPa， 200 kPa and 300 kPa， and temperatures of -1.5 ℃， -0.7 ℃ and -0.3 ℃. Then， the creep deformation behaviors of warm frozen soil under different temperatures， ice contents and load conditions were analyzed. The results revealed that the creep deformations of the warm frozen soils could reach a considerable level， and they showed an attenuated tendency under current conditions. Soil temperature was the most important external factor for influencing frozen soil creep while ice content was the key inherent one. When contained a lot of ice， the warm frozen soil might develop a remarkable variation in creep rate when soil temperature or load changed， even on the order of magnitude. Under current test conditions， the Burgers viscoelastic model could be applied to express the creep deformation process of warm frozen soil with a satisfactory fitting degree.