A view of the construction site of Zhangzi Tunnel. [Photo/zhoushan.cn]

In Zhoushan, East China's Zhejiang province, the right tunnel of the Zhangci Tunnel of the Phase I of the Ningbo-Zhoushan Expressway achieved a breakthrough on May 12 this year.

It marks the first tunnel breakthrough for the Phase I of the project, signaling a crucial advancement in the construction technology of parallel road and rail tunnels.

The Zhangci Tunnel is a critical section of the Phase I of the Ningbo-Zhoushan Expressway. The right tunnel is 311 meters long and its six lanes are designed for a speed of 100 kilometers per hour. The tunnel has a net width of 14.5 meters and a net height of 5 meters. Running parallel to the Ningbo-Zhoushan Railway tunnel, with a minimum net distance of only 9.29 meters, it is considered a typical parallel tunnel with a short distance.

The breakthrough of the right tunnel has opened up a crucial passage for the Ningbo-Zhoushan Expressway on Zhoushan Island, significantly advancing the tunnel construction.

Currently, excavation work on the left tunnel is progressing rapidly, with expectations to have both tunnels excavated by June this year.