青藏高原冻土区路面类型对路基温度场影响的非线性分析

Nonlinear Analysis of the Influence of Pavement types on Embankment Thermal Regime in Permafrost Regions on the Tibetan Plateau

采用焓模型, 建立含相变的冻土路基温度场, 综合考虑气温、太阳辐射、风速风向、坡面蒸发等气象因素, 将诸多气象因素归结为第二、三类边界条件的叠加组合, 对不同气温地区的沥青路面及水泥路面路基温度场进行了有限元计算. 结果表明: 路面类型对冻土路基温度场有着重要影响, 水泥路面的采用可有效地降低路面温度, 延缓冻土上限下降速率, 从而可以有效保护基底多年冻土; 从对基底冻土上限影响的角度来看, 路面类型、外部气温与路基高度三者间存在一定的动态等效关系.

Enthalpy model was adopted to set up a thermal regime of permafrost embankment with phase change. In the simulation of embankment thermal regime, many meteorological factors, such as air temperature, solar radiation, wind velocity, soil moisture evaporation, were considered and concluded as a combination of the second and third boundary condition, accordingly, the finite element models of thermal regime in embankments with asphalt concrete pavement and cement concrete pavement in different temperature areas were set up and analyzed. The calculation results show that pavement types have positive influence on thermal regime in permafrost embankments, and concrete pavement can effectively decrease pavement temperature, delay falling velocity of permafrost table, and protect the permafrost under embankments effectively. Considering the effect on permafrost table, there is a kind of dynamic equivalence to some degree among pavement types, external temperature and embankment heights.