【摘要】 推导冻土相变温度场的数学模型及有限元计算公式,在此基础上分别利用热弹塑性和热弹塑性—蠕变的本构关系,考虑融土和冻土的应力和变形,给出相应的有限元计算公式。以青藏铁路北麓河试验段为计算模型,计算冻土路基的温度场和温度影响下的应力、变形场,并且与实测温度和路基变形数据进行对比分析。计算和分析结果表明:冻土路基下多年冻土层温度随着路基使用年限的增加而逐步升高,形成高温冻土层;冻土路基变形随着时间的增加而增加,最后趋于稳定,这表明冻土的蠕变为衰减型蠕变;路基修筑后3~5年的变形量占变形的绝大部分,此后路基变形进入一个相对稳定的阶段,可满足铁路的正常运营。更多还原

【Abstract】 The author first deduced the mathematical model and FEM equation of phase transition temperature field of frozen soil.On this basis,the author then deduced the corresponding FEM equation by separately employing the thermo-elasto-plastic and thermo-elasto-plastic creep model to consider the stress and deformation of thawing and frozen soil.Taking the Beiluhe test site along Qinghai-Tibet Railway as a computational model,the author calculated the temperature field of frozen soil embankment,and the stress field and displacement field under temperature effect.Subsequently,the results deduced from the model were compared with the observational temperature and embankment deformation data in-situ.Calculation and analysis results show that the temperature of permafrost under the embankment is getting warmer along with the increase of service life,and this warming leads to the emergence of the frozen soil layer with high temperature.The deformation of frozen soil embankment increases with time due to the creeping characteristics of frozen soil and thereby becomes steady at last,and this characteristic shows that the creep of frozen soil is in attenuation trend.The deformation in 3 to 5 year′s time after the construction of embankment accounts for the most part of the whole and then becomes comparatively steady,which meets the requirement of normal railway operation.更多还原