Global warming will accelerate permafrost degeneration in Tibetan Plateau, and the ground ice among the frozen soil will further melt. This process will have a great influence on the stability of engineering geology, and finally it will bring many adverse effects both on water cycles and eco-environment in this region. Therefore, it is very important to master the characteristics of ground ice distribution for predicting its change in future.

Thousands of boreholes have been drilled along the Qinghai-Tibetan Highway (QTH) to investigate the permafrost distribution during the past 50 years. Researchers from the Observation and Research Station of Qinghai-Tibet Plateau, Cold and Arid Regions Environmental and Engineering Research Institute (CAEERI), Chinese Academy of Sciences (CAS) selected permafrost profiles from 697 boreholes, conducted 9261 soil water content measurements, analyzed the characteristics of ground ice distribution.

Based on the horizontal distribution of ground ice and water content revealed from borehole profiles, they divided the permafrost along the QTH can into five types, i.e., low-ice content permafrost, high-ice content permafrost, ice-rich permafrost, ice saturated permafrost and ice-layer with soil. They calculated length of each type of permafrost along the QTH. They also calculated the vertical distribution of ground ice for three vertical sections, i.e., within 1 m below the permafrost table, from 1 to 10 m below the permafrost table, and beneath 10 m below the permafrost table. The average thickness of permafrost along the QTH is about 38.79 m, and the average weighted water content is about 17.19%. Therefore, the total volume of ground ice in the permafrost regions on the Tibetan Plateau is estimated to be 9 528 km3.