Study On The Pathology Mechanism And Methods Of Longitudinal Road Cracks In Plateaus-permafrost Region

The Qinghai～Tibet Highway through many plateaus-permafrost areas, due to formidable natural and complex geology conditions, there are many longitudinal cracks occurring in the line, These cracks are too huge to be maintained with ordinary methods. Therefore, the paper, depending on the field investigation data of Qinghai-Tibet Highway, study the forming mechanism and methods of longitudinal road cracks in plateaus-permafrost region.Through investigated the longitudinal cracks in the fields of Anduo area, according to its generation position and severity, analyzed the characteristic and distributing laws. In the mechanism analysis part, the paper has established the model through analyzing the changing laws of permafrost upper limit and the longitudinal crack traits, then made use of finite element methods proceeding numerical analysis, direct towards practical situation of the permafrost thaw depth continual deepen, in the paper, through the differ cost of thaw depth, study the forming process of the longitudinal crack. The results has revealed that the forming process has three different phases: the initial deforming phase, the strength destroying phase and deforming destroying phase; By practice diagnoses on the line, they are many factors impact on longitudinal cracks, here choose the height of embankment to analyses, and found out the influence law which impact on the longitudinal cracks. In the prevention and cure methods part, grading the cracks at the first and bring up the control principles on the line of permafrost region; then bring up many concrete preventive measures about newbuild road and treating measures of the graded cracks in existence. Through studying, there are three basic maintain methods, including single layer geogrid, the flexible beam and the composite structure of geogrid and flexible beam.