Longitudinal Cracking Mechanism of the Qinghai-Tibet Highway

Longitudinal cracking has been one of the prevalent diseases in the Qinghai-Tibet Highway for decades. It affects the traffic safety and normal operation of the highway. Investigation of damage characteristics and main affecting factors of pavement longitudinal cracking has been done since the opening of the Qinghai-Tibet Highway in the 1950s. Based on the analysis of cross-sectional distribution feature of temperature field, relationship between asymmetric temperature and pavement longitudinal crack was found. Longitudinal cracking of the Qinghai-Tibet Highway especially in sunny—shady slope condition is mainly due to permafrost temperature asymmetry which caused asymmetric distribution of permafrost table and uneven embankment thawing settlement. The longitudinal cracks distribute mainly in the middle or deviation to the sunny slope of the pavement. Based on the mechanism analysis of longitudinal cracking, the prevention proposals for longitudinal cracks of the Qinghai—Tibet Highway are recommended from the aspects of radiation, convection and conduction.