Analysis of Corrosion Failure Mechanism and Construction Technology of Shotcrete in Tunnel Hydrogen Sulfide Environment
Combined with the construction practice of Qilianshan 2#tunnel in the section of Mandala to Datong of National Highway 569,the mechanism of the strength reduction and corrosion damage of the primary support concrete caused by the influence of hydrogen sulfide environment is analyzed.The prevention and control measures are proposed,including using radial bolt plugging method to reduce the contact between hydrogen sulfide and concrete,enhancing the corrosion resistance of concrete itself in the hydrogen sulfide environment(such as using air-tight concrete,sulfate cement to replace silicate cement,and alkali-free quick-setting agent).Through the concrete admixture test and the layered shotcrete thickness test,it is found that the fly ash added to shotcrete has stronger sulfur resistance than the mineral powder,and the layered thickness of 6-7 cm is more conducive to controlling the block rebound phenomenon of concrete.The relevant research results can provide effective reference for the construction of shotcrete in the similar hydrogen sulfide environment.
tunnelhydrogen sulfideshotcreteconcrete failure mechanismprevention and control technology
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