格尔木至拉萨多年冻土区输电线路杆塔基础上拔性能研究-建筑与土木工程专业论文.docxVIP

哈尔滨工业大学工程硕士学位论文 哈尔滨工业大学工程硕士学位论文 万方数据 万方数据 Abstract In China, more and more transmission line project across the permafrost region, but at present there is no design specification of tower foundation in permafrost. In this context, the Northwest Electric Power Design Institute Chinese Power Engineering Consulting Group launched the work to set 《Technical specification for design of foundation for overhead transmission line in frozen soil region》. This paper as a sub project, relying on Golmud to Lhasa transmission line project , will reserach the uplift behavior of expansion slab tower foundation in permafrost. This paper conducts pull-out tests of the tower foundation models. The foundation models are scale down from the excavation expansion slab tower foundation including straight column foundation and cone column foundation. Pull-out tests of foundation models is conducted in silty clay of different water content, different freezing temperatures to get the shape parameters of the failure surface and its change law along with the different experimental conditions, as well as the uplift load displacement curve of foundation model. From analysis, the pull out failure mode of foundation in permafrost is overcome freezing strenghth between foundation and soil-compression of frozen soil above expansion slab-the emergence and development of plastic zone in frozen soil-general shear failure of frozen soil. According to the Golmud-Lhasa transmission line engineering,establish axisymmetric model of straight column foundation and cone column foundation with different depth and different extension plate diameter in permafrost with just freeze and completely melt active layer. The simulation process from the beginning of uplift to general shear failure of permafrost to get the uplift angel of failure surface, find out that its value is close to the value of model test. Research the influence of foundation depth, expansion slab diameter, foundation type to uplift bearing beha