摘要
结合探地雷达对我国东北黑大公路黑北段岛状多年冻土的勘察结果进行了应用分析研究．结果表明，探地雷达可以较为有效确定多年冻土分布区域、厚层地下冰存在位置，是研究多年冻土的一种有效手段．探地雷达勘测结果表明，东北小兴安岭岛状多年冻土现在主要位于山间沟谷洼地、或山间盆地中，地表有积水、塔头草生长茂盛、草炭和泥炭发育的沼泽化湿地是其存在的重要标志；结合20世纪70年代对该区的冻土调查结果，以及线路沿线现存冻土比例推断，在过去30a间小兴安岭岛状多年冻土发生了较为显著的退化；现存黑河-北安公路沿线稀疏岛状多年冻土区的比例约为2％，冻土厚度约2～9m，冻土上限约1～3m．在影响多年冻土分布的因素中，地表水分条件是最为关键的因素，该地表水分通过蒸发吸热、单向导热等作用调节地中热流，并维持一定的净放热，在年平均气温接近0℃的条件下仍可以维持冻土的发育和存在；其它影响因素，如地形、地貌、坡向、植被、地质条件等因素发挥次要作用．
In this paper, ground penetrating radar （GPR） was employed for the patchy permafrost along the Heihe-Bei＇an Section of the Heihe-Dalian Highway, which shows the result that GPR can distinguish the distributional range of permafrost obviously so that it is an effective method on studying permafrost. The GPR survey results show that the existing permafrost of the patchy permafrost area in Xiao Hinggan （in the northeast of China）, marked by shallow water over the surface, flourishing carex meyeriana and developed turf and peat, mainly locate in intermountain ravine lowland or basin. Comparing the investigation of the permafrost in this region in 1970s with the existing rate of permafrost along the road, in research finds that in the past 30 years, Xiao Hinggan island permafrost degenerated widely. At present, the existing rate of permafrost along the road is about 2%, the thickness of permafrost 2-9 m, and the table of the permafrost is about 1-3 m. In the factors that influence the distribution of the permafrost, the surface moisture is the most important, which adjusts the geothermal flow, keeps a certain net heat emission and the development and existence of the frozen soil even when the annual mean temperature is a right temperature near 0℃ by some effects such as evaporating and heat absorption and unidirectional heat conduction. And other influencing factors such as topography, physiognomy, exposure ground and geologic condition influence the temperature by the surface moisture.
出处
《冰川冻土》
CSCD
北大核心
2008年第3期461-468,共8页
Journal of Glaciology and Geocryology
基金
中国科学院"百人计划"项目"气候变化条件下
高温冻土区线性工程稳定性研究"
国家自然科学基金杰出青年基金项目(40625004)
中国科学院西部行动计划项目(KZCX2-XB2-10)资助
关键词
探地雷达
岛状多年冻土
特性
影响因素
ground penetrating radar （GPR）
island permafrost
characteristics
influencing factors
