On September 16, as the massive cutterhead of the "Jiaozhou Bay No. 5" shield machine slowly began to rotate, it marked the successful launch of five shield machines in just 145 days on the Qingdao Metro Line 8 Branch, and the line officially entered a new phase of tunneling from the suburbs toward the Jiaozhou urban area.

On the Dagu River Museum Station–Shaohai North Station section right line of the Line 8 Branch, tunneling proceeds northward along the right bank of the Dagu River dike, passes beneath the planned Shanghe Avenue road and the Baolong Historical and Cultural Street, then turns into Yangzhou Road, passes alongside the Canal Bridge, and is lifted out at Shaohai North Station. The tunneling length is 1,963.108 meters in total, with a maximum burial depth of nearly 30 meters, equivalent to about an 11-story building.

The "Jiaozhou Bay No. 5" shield machine is a composite earth pressure balance shield with an excavation diameter of 6.5 meters, an overall length of about 90 meters, a total weight of about 500 tons, and a maximum thrust of 4,160 tons.

Since the launch of the first shield machine, "Jiaozhou Bay No. 1," on April 24, five shield machines have been launched over 145 days. The shield launches came one after another like dumplings being dropped into a pot, averaging one launch every 29 days, setting a new record for shield launch frequency in the third phase of Qingdao Metro construction.

The Qingdao Metro Line 8 Branch starts at Dajian Station and ends at Jiaozhou Railway Station, with a total length of about 20.4 kilometers. The line has 12 stations and 12 sections in total, with a designed maximum speed of 120 km/h. It is an express corridor serving the passenger flow between the Jiaozhou cluster and the Hongdao Economic Zone and Airport Economic Zone in the north coast urban area, as well as the east coast urban area. Once completed, the line will accelerate the integration of Jiaozhou with Qingdao's main urban area and help bring Jiaozhou into Qingdao's "one-hour living circle."