| The Railway construction from Hami to Lop Nur Xinjiang Uygur AutonomousRegion(hereinafter referred to as the Ha-Luo Railway) section DK298+130toDK383+984.3, about86km long, needs to use halite as a filler for roadbed construction,which is China’s longest Railway roadbed construction using halite, and also the first tryin the history of Railway construction in China to fill the roadbed with sulfuric halite，Sulfate has significant expansion characteristics,which can distory the roadbed andmake the Railway unsafe by salt explosion when the miosture and tempeture change.Lop Nor halite has saline expansion, melt sinking, and corrosion and other badengineering properties. The Ha-Luo Railway construction requires the engineering andtechnical personnel to determine the technique of the base treatment of railway bed, thecompaction standards, testing technology, halite and foundation stability evaluation onthe basis of grasping the ill characteristics such as saline expansion, collapsibility andcorrosiveness of the halite. This essay does a series of field tests and laboratory testsabout the Ha-Luo Railway halite roadbed, analyses the subgrade characteristics of saltexpansion and deformation of the law by observing the temperature, moisture,settlement data of the subgrade, and compares which is more reasonable andeconomical among impact rolling, heavy grind pressure and hammer compactedsubgrade construction working methods. Through normal soil test, salt expansion teststo make out of the engineering characters of halite as the subgrad, and analyse therationality and provide the theoretical support.It’s the first time to do the simulation study about the halite roadbed by finiteelement of MIDAS-GTS geotechnical engineering software, through simulating thevarious stages of embankment construction and construction sequence, compare theparameters of the roadbed under different construction sequence, and then determine theoptimal construction method. |
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