On March 3, at the construction site of the working shaft on the Jintang Island side of the Jintang Subsea Tunnel of the Ningbo-Zhoushan Railway, a shield tunneling machine weighing more than 100 tonnes was being lifted and lowered into the shaft.

　　As the high-speed railway subsea tunnel with the largest diameter in the world (maximum excavation diameter 14.57 meters), the Jintang Subsea Tunnel runs from Beilun, Ningbo in the west to Jintang, Zhoushan in the east, with a total length of 16.18 kilometers, of which the shield-driven section is 11.2 kilometers long, with a maximum burial depth of 78 meters; the tunnel crosses beneath the 100,000-tonne-class Jintang main navigation channel. Two shield machines will be used to bore from the Ningbo and Zhoushan sides toward each other, ultimately achieving breakthrough by meeting under the seabed, after which they will be dismantled to complete the tunnel construction.

　　According to reports, what is being lifted and lowered on site is the middle-section equipment of the connecting bridge of the "Dinghai" shield machine for the Jintang Subsea Tunnel of the Ningbo-Zhoushan Railway. The entire shield machine is divided into 4 trailer sections and one connecting bridge, of which the connecting bridge serves as the material transport and lifting load-bearing passage for shield tunneling, providing logistical support for shield advancement.

　　At present, trailer sections No. 4 to No. 2 of the shield machine have been lowered into the shaft and completed, and the "teeth" (cutterhead) of the "Dinghai" shield machine are being assembled and welded simultaneously; the cutterhead is expected to be lowered into the shaft on April 10.