Construction Technique Of Large-diameter Ductile Iron Pipe In Valley

This paper mainly discusses the construction technique of large-diameter ductile iron(DI)pipes in complex valley that applied in the capacity expansion and technical upgrading project of Jinchuan Group Power Plant.The study tackles with the difficulties of DI pipe construction in valley,including the complex hydrologic and geologic conditions with high underground water mark,long distance,and multiple corners,as well as the substantial weight of pipes.Upon the analysis of the hydrogeological conditions,local environment of the construction site,and corresponding large-diameter DI pipe construction technique,the paper presents a new construction technique of combined applications of “drainage at the whole construction site with dewatering in specific spots,support and protection by bamboo scaffolding,T-type flexible connection+ bearing or short-joint connection+ homemade steel and lead joint”.The research helped solve various problems in the course of the project construction,ensuring a smooth progress.In addition,on the premises of successful completion,the research helped reduce construction costs and thus lowered the total project costs,indicating both direct and indirect economic benefits.Meanwhile,the study achieved breakthrough to implement large-diameter DI pipe construction in traditional ways,enabling the pipes to be applied in a wider range of techniques,which can be used in various kinds of geological conditions from plains to valleys.It is of the great value of reference for similar projects under complex geological conditions in the Hexi Corridor and Qinghai-Tibet Plateau,implying significant social and economic benefits as well as a broad prospect for application.