PERMAFROST ENGINEERING GEOLOGICAL CHARACTERISTIC AND DISCUSSION OF ROUTE SELECTION IN QINGHAI-TIBET PLATEAU

Qinghai-Tibet 500kV DC power transmission line traverse the permafrost in Qinghai-Tibet Plateau, special engineering problems of permafrost will have the important impacts on the engineering design, construction and safe running. Because of structural trait of point and linear engineering, this means stability of tower footing have relation to the stability of all the line, but the tower footing is adjustable in degree. So the distributing character of permafrost and ground ice have more significance for the route selection and position selection than other linear engineering. In the base of distribution of permafrost along the transmission line, the article primarily study and analyze the rules of distribution and development of frozen soil and thick ground ice under the condition of tiny landform and physiognomy, and combining the engineering characteristics of transmission line, the principles of the route selection and position selection are studied and confirmed.