Study on the status of subgrade engineering in permafrost region during the early operation of the Qinghai-Tibet railway

The Golmud-Lhasa section of the Qinghai-Tibet railway (QTR) is 1,142 Km long, of which 550 Km is in permafrost region. Studies on the status of subgrade engineering in permafrost region are complicated by the intervention of temperature and water and railway operating conditions. Based on in-site investigation and monitoring during the early operation of the QTR, we studied the status of subgrade engineering from three aspects, subgrade deformation, geothermal changes and hydrothermal conditions, and proposed solutions to subgrade cracks to ensure railway safety and conservation.