青藏铁路冻土路基变形监测与分析

基于现场监测资料,对作为青藏铁路中的主要保护冻土的几种路基形式(如:通风管路基、块石路基、块石护坡路基、保温材料路基和普通素土路基)进行了变形和温度分析,发现所有路基的变形均以沉降变形为主,且其变形与其下伏冻土的地温场变化密切相关.经过2～3个冻融周期后,通风管路基、块石路基、块石护坡路基和保温材料路基的变形已趋于稳定,而无任何措施的普通路基目前变形仍未稳定.另外,各种路基左右路肩均存在变形差.基于以上分析可得到一个启示:在高温、高含冰量冻土地区,由于路基下多年冻土温度升高产生的高温冻土压缩变形而引起的路基沉降变形具有相当大的量级,很有可能成为冻土路基发生破坏的一个重要原因,工程实践中应给予足够的重视.

Monitoring and analysis of embankment deformation in permafrost regions of Qinghai-Tibet Railway

Based on in-situ monitoring of the duct-ventilated embankment, the crushed rocks embankment, the embankment of crushed rock slope protection, the thermal-insulation treatment embankment and the common embankment along Qinghai-Tibet Railway in permafrost regions, the embankment deformation and the change of ground temperature under these embankment are analyzed. It is found that the embankment deformation are of behavior of settlement and closely related with the change of ground temperature under these embankment. After 2-3 freezing-thawing circles, the deformation are tending towards stability in the duct-ventilated embankment, the crushed rocks embankment, the embankment of crushed rock slope protection and the thermal-insulation treatment embankment; but the settlement of common embankment is not stable yet. Meanwhile, the deformation difference of the right-and-left shoulder of embankment is still existent and changed with different embankment types. Based on above-mentioned analysis, we also can obtain a revelation that the compressive deformation of warm frozen soil due to rise of ground temperature under embankment may cause bigger settlement of embankment, maybe it will be one of main reason to result in embankment failure in permafrost regions with warm and high ice content; we should pay much attention to it.