Research On Chloride Ion Corrosion Resistance Of Pile Foundation Of Transmission Line In Coastal Areas

With the rapid development of China's electric power industry,a large number of power transmission lines must pass through the coastal beach.The corrosion of iron pile foundation caused by seawater and saline soil will result in corrosion damage which is different from that in inland area.Once an accident occurs,it will cause great losses.Because of the low groundwater level in coastal areas,the application of pile foundation of transmission lines is more common,However,according to the relevant provisions of "Code for anticorrosion design of industrial constructions(GB 50046-2008)",the pile foundation type shall not be adopted when the concentration of sulfate ion or chloride ion reaches the strong corrosion grade.Other the requirement of concrete strength grade is relatively high in strong and medium corrosive areas,which bring a lot of inconvenience to the foundation design of coastal areas.According to the characteristics of corrosion environment in the coastal areas and the transmission line project characteristics,we investigate the durability of reinforced concrete foundations for transmission lines in coastal areas,and we have reinforced,reinforced concrete components and concrete blocks to resist chloride ion accelerated test in the laboratory simulation of corrosion environment.According to the field investigation and indoor accelerated test,we put forward that the filling pile foundation can be adopted when the transmission line adopts proper corrosion protection measures under the strong corrosive environment.Based on the field investigation and theoretical analysis,in the coastal areas of strong and medium corrosion conditions,pile foundation is high performance concrete with ordinary portland cement mixed with fly ash and fine slag powder of blast furnace,under the environment of strong corrosion,the strength grade of concrete can be reduced to C35,and the strength grade of concrete can be reduced to C30 under medium corrosion environment,and we propose that the protective layer thicknesses of the bored pile foundation of the transmission line in the two corrosive areas are 70 mm and 65 mm.According to the field investigation,with the passage of time,the weathering degree of the anticorrosive coating is particularly serious,and the coating has basically disappeared,so the anti-corrosion effect needs to be further studied.In this paper,the effect of anticorrosive admixture is verified by experiments,and we suggest adding antiseptic additives to concrete of the foundation.