Study Of Technique Of Pier And Bored Pile Concrete Construction In Perennially Frozen Soil Zone

Qinghai-Tibet Railway (Section of Germu to Lhuasa) is 1118 km long , of which 965 km long line passes through the plateau at the altitude over 4000 m , and 550 km long line passes through the continued permafrost soil. The engineering geological phenomenon of permafrost soil will produce the bad effect on railway construction administration. concrete structure will be destroyed by the frost heaving, thaw collapse, chemistry corrosion, reinforcing steel bar rust, bland and sand weathering, etc. These will directly affect the stability of the bridge and culvert.The two key technical problems to be faced in railway construction and operation administration are plateau (with altitude over 4000 m) and frost soil, which includes permafrost and seasonal frost soils.In this paper, the engineering geological problems of the plateau in related to the railway to be constructed in permafrost soil zone were introduced and analyzed. Based on that, the effect of frost heave, thaw collapse along with the impact of serious environmental conditions on the construction of railway bridges and culvert at the plateau were discussed. In this environment, the concrete should have not only mechanical performance, but nicer early intensity in negative temperature, anti-frost performance, anticorrosion of so42- performance, anticorrosion of cl- performance, and anti-bland and sand weathering performance. The enduring concrete design principle were made by collecting and utilizing production, relating engineering practice, doing experiment of performance parameters, doing experiment of performance change in diverse conditions, doing experiment indoor simulating practice, accounting for data and then contrasting it with indoor experiment. This leads to the development of a whole series of techniques with regard to pier and bored pile concrete construction in perennially frozen soil zone. Good technical and economy results were obtained through the application of all these techniques. Finally, the whole series of techniques were brought forward, the results were made use of to guide the engineering construction, and to obtain the good practical results.