Frost Damages in Permafrost Regions along the Qinghai-Tibet Railway in 2001—2006:Investigation and Analysis

Permafrost is a principal engineering-geological problem in the construction of Qinghai-Tibet railway.Along with the construction of embankment,bridge etc., the permafrost condition has been change since 2001,which may influence the permafrost stability.In this paper,the investigations in winter and summer year by year are introduced.In 2002,crevices was discovered in embankments in permafrost regions by winter investigation;in 2003,ice-cone,ice-mantle,concrete erode,sand disaster etc.were discovered by winter investigation;in 2004,seepage from embankment,icing in culvert were discovered;in 2005,less damage to the railway was found.Then,the permafrost condition is analyzed based on the winter and summer investigations in the constructing period,the control measures against frost damages are put forward step by step,and a synthetical scheme,i.e.,taking actively protecting permafrost as the principal measures,assisted with passively protecting permafrost,was suggested.With the deeply understanding the permafrost propertied,the applying the investigation results to the design of railway,improving the design method,and changing the design ideas,a new dynamic design was established for the Qinghai-Tibet railway.