【摘要】 块石结构路基以其独特的冷却路基作用,正在发挥着良好的降低多年冻土温度作用。但块石结构层被风沙或积雪堵塞后,路基下部多年冻土降温效果变化一直是人们极为关注的问题。为此,开展了开放和封闭条件下块石结构路基下部多年冻土降温效果差异的现场试验研究,对比分析开放和封闭条件下路基下部土体温度的变化特征。试验结果表明,开放状态下块石路基具有较强的强迫对流效应,封闭状态下块石路基强迫对流效应较弱,这一差异导致了开放条件下,块石结构路基下部土体降温效果比封闭条件下要好得多。从路基下部0.5～1.0m深部土体温度来看,二者间夏季差别不大,冬季最低温度要相差5℃左右。从块石路基下部土体降温的影响深度来看,开放条件下土体降温的影响深度可达6.0～10.0m,封闭条件下土体降温影响深度仅为1.5～3.0m。更多还原

【Abstract】 Block-stone embankment with cooling roadbed has effects on lowering permafrost temperature.However,effect variation of lowering permafrost temperature beneath block-stone embankment is a significant issue after block-stone layer is filled by sand or snow.The field experimental research on cooling permafrost temperature beneath open and closed block-stone embankments is developed to compare the change of permafrost temperature.The results show that extensive convection can be produced in the layer of block-stone for open block-stone embankment,but weak in the layer of block-stone for closed block-stone embankment.The different results from more extensive effect on cooling temperature for open block-stone embankment against that for closed block-stone show the superiority of open block-stone embankment.In view of soil temperature at the depth of 0.5–1.0 m beneath open and closed block-stone embankment,the difference is minor in summer,but large in winter,where the lowest temperature of soil beneath open block-stone embankment is about 5 ℃ lower than that beneath closed block-stone embankment.In view of effect depth of cooling temperature for the soil beneath embankment,the effect depth of cooling temperature is up to 6.0–10.0 m for open block-stone embankment,but is only about 1.5–3.0 m for closed one.更多还原