Ground penetrating radar surveys for permafrost assessment in the Qinghai-Tibet Plateau, China

The degradation of permafrost poses severe adverse impacts to the stability of the foundation of critical infrastructures like highway built on permafrost region like the Qinghai-Tibet Plateau. Stabilization of the highway subgrade of the Qinghai-Tibet highway is still an unsolved problem and continuously poses threat to the operation of the highway as the major geo-hazard. The state of permafrost varies between freezing and thawing to respond to ambient temperature changes and this process generates the normal active layer above the permafrost. At a Cryosphere Research Station on the Qinghai Tibet Plateau (CRSQTP) near Xidatan, Qinghai, the depth of active layer ranges from 2.0 to 2.6 m and the depth of permafrost base ranging from 24 to 25m [Cheng and Wu, 2007]. New data show that soil temperatures at depths from 5 to 10 m increased by about 0.2°C between 2001 and 2003 [Cheng and Wu, 2007]. GPR surveys have been conducted on a site on the Beiluhe of Qinghai-Tibetan Plateau to characterize the status of the permafrost for fundamental geology and hydrogeology studies, as well as provide fundamental information for solving the engineering problem for stabilize foundations of civil infrastructures on the plateau region. This paper will report the newest results of our GPR observations in this region.