Major progress has been made in the construction of the power tunnel on the north extension of Wanjiali Road in Changsha. As of July 22, the shield-driven section has completed 3,298.4 linear meters of main-line excavation, and the open-cut section has completed 1,800 linear meters of main structure, with total excavation surpassing the 5,000-meter mark.

The power tunnel on the north extension of Wanjiali Road starts from Teli West Road in the south and ends north of the planned Information Avenue in the north, with a total length of about 7.6 km. The shield-driven section is 5.1 km long, and the open-cut section is 2.5 km long. The project faces challenges including passing beneath subway ancillary structures three times, complex pipelines along the route, shield tunneling with a small turning radius, relatively steep designed gradients in the section, high excavation difficulty and high risk, and a complex construction environment.

In the shield-driven section, three shield machines, like "underground dragons," work simultaneously in different shield intervals. They "swallow" underground mud, sand and stones, then transport the material to the portal via screw conveyors, belt conveyors and rail battery locomotives, and finally hoist it out of the tunnel with gantry cranes. Advanced techniques and construction methods ensure the orderly progress of the project.

Since July, all project participants have braved the intense heat to maintain progress, setting off a construction climax in the third quarter. To ensure the schedule, more than 30 excavators, cranes, transport vehicles, concrete vehicles and other equipment in the open-cut section have been working day and night. The excavation advance of the three shield machines has been maintained at about 35 meters per day, with a maximum daily advance of 42 meters.

It is reported that this power tunnel project is an important part of the Changsha Wanjiali Road rapid transformation north extension project. Once completed, the project will effectively solve the existing traffic saturation problem on Wanjiali North Road; at the same time, it will ease the pressure on the power grid in the eastern area of Changsha and provide a stable power source for the operation of Metro Lines 3 and 5. According to the plan, the power tunnel project will be completed this year, and the bridge project will be completed and opened to traffic by the end of 2022.