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基于青藏公路沿线高温冻土区和低温冻土区 2组地温观测孔 5a的地温观测资料 ,研究了路基下伏多年冻土的融化状态 ,定量分析了进入路基下多年冻土内的热状况 .结果表明 :路基近地表地温明显高于对应天然地表下的地温 ,路基近地表经历的融化期长于对应天然地表 ,高温冻土区路基内已形成贯穿融化夹层 ;进入高温冻土区路基下伏多年冻土内的热收支处于持续不断的吸热状态 ,进入低温多年冻土区的热收支也呈现出吸热明显大于放热的周期性变化 ;高温冻土区接近 0℃的地温及其持续不断的热积累是引起下伏多年冻土不断融化的主要原因 .低温冻土区进入多年冻土的热积累暂时以增高地温耗热为主 ,随着地温的增高 ,低温冻土区也可能发生强烈的冻土融化 .
Based on the observation data of two sets of geothermal observation holes 5a in the high temperature permafrost zone and the permafrost zone along the Qinghai-Tibet Highway, the thawing status of permafrost beneath the embankment is studied and the thermal conditions in the permafrost beneath the embankment are quantitatively analyzed. The results show that the near ground surface temperature of subgrade is obviously higher than that of corresponding ground surface under natural ground surface. The melting time of near surface subgrade is longer than that of corresponding natural surface. The subgrade of high temperature permafrost zone has formed through the melting interlayer. The heat budget in permafrost is in a state of continuous heat absorption, and the heat budget of the permafrost entering the low temperature also shows a periodic change of endothermic heat significantly greater than that of exothermic. The continuous accumulation of heat is the main cause of the continuous melting of the underlying permafrost.The permafrost enters the permafrost for a time to increase the temperature and heat loss for the time being, with the increase of ground temperature, permafrost may also be A strong permafrost melts.