| Due to the advantage of small disturbance to the soil around the tunnel during the construction,shield tunnel technology has gradually become to the main construction method of urban underground space development.And there is no need to dismantle exist building and underground structure with shield method as well in underground space construction.The tool configuration is a key link in the design of shield machine,and the configuration of which is whether suitable for the geological conditions of the project or not,could directly affect the working life,boring speed and construction efficiency of the shield machine cutting wheel.When tool has been wore,tool replacement with safety,economy and efficiency is particular important.To discuss tool configuration and replacement of large diameter shield based on project practice is of great significance to the shield construction.The structure design of cutting wheel,as well as the classification,function and arrangement method of the cutter have been reviewed in this paper.In addition,wear failure and inducement factor of cutting knife and hob have been discussed and analyzed based on the cutting mechanism.And tool arrangement of large diameter shield has been researched according to the application of S-978 shield machine.The influence of different geological conditions,especially the complex strata on the wear of different types of tool has been analyzed based on the condition of tool replacement.From practice,the technology of exchanging cutter for soft soil layer,hob exchanging and the technology of exchanging hob and scraper under atmospheric pressure is demonstrated in this paper.And the process of tool replacement is also introduced as well.In addition,problems and solutions in tool exchange process have been summarized.Besides above,this paper has introduced the preparatory work and concrete operation process of tool exchange with high pressure,as well as work principle and precautions of working in/out of the excavation chamber. |
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