高温高含冰量地区片块石路基冻融指数变化分析

Analysis of freeze-thaw index of block-stone embankment in warm and ice-rich permafrost region

冻融指数反映了路基热能和冷能蓄积的大小,是评价多年冻土分布、了解冻土变形的重要指标。本文针对沥青路面下高温高含冰量地区片块石路基的地温、冻融指数变化特征进行了分析,发现沥青路面吸收了较多的热量传送给路基下部土体,下伏多年冻土仍处于融化状态。从路基融化指数、融冻比及温度比来看,路基阴阳坡效应严重,路基中心和阳坡年平均融化指数大于冻结指数,阴坡则相反。而不论阳坡还是阴坡,块石层层顶冻结指数均要小于融化指数,年积温为正值,表现为吸热状态。

The freeze-thaw index reflects the thermal,cold energy accumulation of embankment,and is an important index to evaluate the distribution of permafrost and understand the deformation of permafrost.In this paper,the ground temperature and freeze-thaw index of block-stone embankment with asphalt pavement in warm and ice-rich permafrost region are analyzed.It is found that the asphalt pavement absorbs more heat and transfers it to the soil below the subgrade,and the underlying permafrost is still in the state of melting.According to the thawing index,thawing ratio and temperature ratio of embankment,there is a serious sunny-shady slope effect.The annual average thawing index of embankment center and sunny slope is greater than that of freezing index.The freezing index at the top of the rock layer is less than the melting index on both sunny and shady slopes,and the annual accumulated temperature is positive,showing an endothermic state.