多年冻土区路基高度对温度场影响的非线性分析

采用焓模型,综合考虑了气温、太阳辐射、风速风向、坡面蒸发等气象因素,对不同气温地区多种高度路基温度场进行有限元数值模拟,并采用天然地面下冻土年最大融深及路基内融土核高度两个指标综合分析路基稳定状况。有限元分析表明:在中低温多年冻土地区,抬高路基可延缓冻土下降速率,有效保护多年冻土;在高温不稳定多年冻土地区,抬高路基的效果并不显著,过度地抬高路堤会使路基内融土核高度显著增加,路基本体的稳定性将受到严重影响。本文还提出路基高度与冻土年最大融深之间的回归公式,为路基病害预测提供依据。

Nonlinear Analysis of Influence of Embankment Height on Embankment Thermal Regime in Permafrost Regions

Enthalpy model was adopted and many meteorological factors,such as air temperature,solar radiation,wind velocity,soil moisture evaporation,were considered in simulating thermal regime of embankments with different heights.Meanwhile,two index,including annual maximum thaw depth of underground permafrost and thaw soil height in embankments,were adopted to analyze embankments' stability.Finite element method(FEM) calculation results show that,in low temperature permafrost regions,by raising embankments height it is possible to delay falling velocity of permafrost table and to protect permafrost effectively,but in high temperature unstable permafrost regions,its effect is much smaller,and over raising embankments height can result in enlargement of thaw soil height and decrease the stability of embankments greatly.The regression equations of embankments height and annual maximum thaw depth of permafrost were put forward to provide evidence for disease forecast of permafrost embankments.