The change of heat and water process of the active layers at the engineering sites is intenser than that at the original surface site, and the permafrost stability of the engineering sites is lower than that at the original surface site.

• 冻融期间工程活动场地活动层的水热状态变化要比天然场地强烈而且差异较大，工程活动场地冻土的稳定性比天然场地低。