Migrating pingos at the 83rd Station of the Qinghai-Tibet Railway and their engineering controls

There are six typical migrating pingos along the Qinghai-Tibet Railway and freezing and swelling of some of these pingos caused fracturing of bridge piers and culverts and bending of oil pipelines along the railway and highway. The migrating pingo near the 83rd station occurs at the site of intersection and compounding of two sets of faults at the south side of the Erdaogou basin and is a migrating pingo induced by the underground construction of bridge piers in a fractured zone. It consists of a 0.5 m thick ice mantle and a 2.5 m high pingo in winter and becomes spring water ponds in summer after melting of the pingo. The pingo was considered as one of the potential hazards to the railway. Dams, spring water pools and conduits were constructed at the site east of the railway bridge where spring water was concentrated. These engineering works changed the paths of surface and underground spring water, reduced the concentration of spring water at the bridge piers, eliminated the ice mantle and migrating pingo surrounding the bridge piers and successfully ensured the safety of the railway bridge east of the 83rd highway station. Engineering controls on spring water near the 83rd highway station provides new experience for controlling geological hazards of migrating pingos along the Qinghai-Tibet Railway.