On March 16, with the safe and smooth entry of the shield machine into the steel sleeve, the right line of the shield section of Ningbo Rail Transit Line 7 Jiulong Avenue Station ~ Zhenhai Avenue Station undertaken by China Railway Second Bureau Chengtong Company was successfully completed, 12 days ahead of the owner's node construction period.

Jiulong Avenue Station ~ Zhenhai Avenue Station shield section of the right line is 1599.6m long, the minimum radius of the line plane R = 2500m, the maximum longitudinal slope of 24‰, the interval mainly crosses silty clay and silty clay, the soil layer has obvious characteristics such as high water content, strong fluidity, high compressibility, low strength and poor permeability, etc., at the same time, in the process of tunneling, it is necessary to cross the bridge pile foundation, river, pipeline, urban main road, etc., the ground surrounding environment is more complex, the construction accuracy requirements are high, and the settlement control requirements are strict. Affected by various factors such as the short reinforcement length of the receiving site, the proximity to the main traffic roads and important pipelines, the steel sleeve process was used for the reception of the Jiuzhen section. Compared with the traditional receiving method, the steel sleeve receiving has the characteristics of high safety, strong adaptability and reusability. In order to ensure the smooth reception of the shield, the project department scientifically planned and carefully organized, while doing a good job of daily inspection and ground monitoring during the shutdown and pressure maintenance, actively connected with external units, completed the scheme review and material entry in advance, and finally completed the installation and pressure holding test of the steel sleeve in only 5 days after the delivery of the receiving site, laying a solid foundation for the smooth breakthrough of the interval tunnel. At present, the left line of the nine towns of the project is also in full swing. In the next step, the project department will go all out to complete the remaining construction and production tasks safely and efficiently.