| The arid and cold region in Qinhai province is located in plateau, rapid climate change, long cold season, the lower average annual temperature, higher diurnal temperature range, arid climate,250mm less average annual precipitation. Asphalt pavements in the region prone to low temperature and semi-rigid base shrinkage cracks. It is very practical significant that analysis the mechanical state of asphalt pavement of the arid and cold region in Qinghai province in its special climate conditions for this region's asphalt pavement structure design.The thesis investigated the environmental characteristics, traffic volume and traffic composition, three trunk highways'asphalt pavemet main structures and damage types of the arid and cold region in Qinghai province. Based on these findings,the reasons of the asphalt pavement damage caused were analyzed. On the basis of a review of relevant literature and research, as the asphalt pavement for research object,the thesis uses the finite element software ANYSY, sets up thermal-structure coupling two-dimensional finite element model. Asphalt pavement thermal stress law that influenced by the thickness of asphalt surface,asphalt mixture temperature shrinkage index, modulus of asphalt surface, diurnal temperature range, thickness and modulus of base course was obtained, with calculating asphalt pavement thermal stress under temperature cyclings. Pre-cut semi-rigid base course asphalt pavement structure in the arid and cold region in Qinghai province is advanced. Thermal stresses of pre-cut semi-rigid base course asphalt pavement with different pre-cut spacing under temperature cycling are calculated and analyzed. Finally, the method for determining pre-cut semi-rigid base course asphalt pavement reasonable pre-cut spacing is advanced. And, design method of preventing low tempreature cracking in the arid and cold region is advanced. The design process for preventing low temperature crackinng in the arid and cold in Qinghai province is given. |
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