| Shield is a special engineering machine which is used in tunnel excavation and nowadays its best period of development is coming. When shield is running, extremely high reliability is needed. Foamed-soil system divided into foamed-soil circumfluence system and foamed-soil treatment is the key device used to keep shield running normally. Foamed-soil circumfluence system having four work modes is used in foamed-soil transport and foamed-soil circumfluence is carried out in excavation mode. The old circumfluence control system cannot meet the demands of the project, because it had many weakness that system accessories were difficult to purchase, adding pump and renovation project was both inconvenient. In order to meet the requirements of the industry, the control system with highly reliability, scalability and high performance is needed.New circumfluence control system was isolated with the host shield control system. AC motors with AC converter ATV71 were chose to drive mud pump. The article combined with mathematical models of some construction condition parameters provided the power formula of mud pump package, that is , the selection criteria of AC motor. The selection criteria and advantages of converter was described and the main performance parameters value of ATV71 was given to verify its feasibility.The article used high reliable homemade PLC-Guodianzhishen EDPF-BA series as the core of circumfluence control system. LICON CUTE400 was used as the controller of master station and slave stations and master station communicated with slave stations by industrial Ethernet. Slave station communicated with converter by Modbus card to achieve the exchange of information so that the information of converters was displayed in master station and master station can remotely control motors'speed. The master station located in the control center of shield and it can remotely monitor every slave station status. Modular compiler program facilitate the expansion of the master station. For the environment characteristics of shield running, industrial touch screen was selected as HMI and every typical frame was given.The article provided the system debugging steps and methods. The system has been successfully used in the some sections of Yangtze River Tunnel Project and last several months. During the running time there are no trouble happening and the system has good real-time stop. The practice shows that the system fundamentally guarantees the stability of foamed-soil circumfluence system and carries out foamed-soil circumfluence automation. |
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