Wenzhou Oujiang water diversion project Zeya shallow buried shield tunnel through, "Zhengxian" to complete the river bottom crossing

On May 9, the "Zhengxian" composite earth pressure balancing shield machine of Zeya shallow buried section of Oujiang water diversion project successfully crossed the bottom of Shupu River and reached the predetermined position to achieve tunnel penetration.

The Oujiang River water diversion project involves 6.7 kilometers of iron, which is the most complex geological condition, the most risk sources and technology methods, and the most safe and technical difficulty of the Oujiang River water diversion project. The shallow buried section of Zeya tunnel is constructed by shield tunneling method. After 9 geological changes, under the complex formation conditions such as rich water permeable sand gravel drifter isolated stratum and extremely hard rock, the double tunnel path crosses the risk sources such as Shupu River and Zhouao Large Bridge of Jinwen Railway. The project team has passed technical research. The innovative use of "freezing method" formation reinforcement, Hengdun mud warehouse construction, Samson life maintenance system, dynamic design optimization of tool physical properties, disassembly and reception of tunnel equipment and other technology methods has solved the safety technical problems of shield tunnel engineering under complex environmental conditions, and played the prominent role of new quality productivity in the project construction stage.

The cutter head diameter of the shield machine is 6.47 meters, the total length of the machine is 85 meters, composed of the main shield and the rear supporting 6 "trolley", each trolley has its own unique system functions, both the operation room, synchronous grouting system, secondary grouting system, water circulation system, belt conveyor slag and other functions, the total weight of more than 500 tons. In order to ensure the safe, stable and efficient promotion of the "Zhengxi" shield machine, the project team has set up a scientific research team, organized a team of experts in the industry, innovative technology research, formulated scientific and feasible construction plans, adhere to the dynamic management of dangerous sources, the acceptance of dangerous processes, and implemented safety measures such as leadership and emergency support. It has organized 11 times (400 warehouses) of silo operations (including the Shupu River bottom belt pressure opening warehouse operations), "5 plus 2, white plus black", and completed the completion of the iron tunnel in the shallow buried section of Zeya in 365 days.

It is reported that since the construction of the iron section of the Oujiang River water diversion project in June 2022, a total of 6247.26 meters has been completed, completing 92.56% of the total design volume, creating favorable conditions for the Oujiang River water diversion project to achieve full line penetration this year.