东北多年冻土区活动层水分迁移规律研究

RESEARCH ON THE MOISTURE MIGRATION OF ACTIVE LAYER IN PERMAFROST ZONE OF NORTHEAST CHINA

为进一步研究多年冻土区零点幕的形成机理、水文与水资源环境变化特征、森林植被演替规律,解决寒区工程建设冻胀问题,文中通过对东北中高纬度岛状多年冻土区活动层地温及水分变化特征的监测,阐述了年水分循环3个阶段的迁移过程,以及年水分迁移总量下移,在活动层底部形成多层1~2mm薄冰层的原因。研究结果表明,水分迁移后的土层导热性突减、能量损失、相变潜热耦合作用是形成零点幕的决定因素。

This paper studies the formation mechanism of zero curtain,the changing characteristics of hydrology and water resources,and the succession of forest vegetation in permafrost region to solve the frost-heaving problem of en⁃gineering construction in cold regions.Through monitoring the characteristics of ground temperature and water changes in the active layer of the island like permafrost region in the middle and high latitudes of Northeast China,the migration process of three stages of the annual water cycle and the downward movement of the total amount of an⁃nual water migrationare illustrated.The reason for the formation of multiple 1~2mm thin ice layers at the bottom of the active layer are discussed.The results indicate that the sudden decrease in soil thermal conductivity,energy loss,and the coupling effect of phase change latent heat after water migration are the determining factors for the for⁃mation of a zero-point curtain.