In Jiaozhou Bay, near Qingdao, three Herrenknecht Mixshields with diameters of 15.56 and 8.14 meters are excavating the "2nd Bay Tunnel Project". A three-lane, twin-tube highway tunnel is being built under the bay. 

The 170-metre-long and 4,500-tonne heavy "Deep Blue" Mixshield is responsible for the 3,225-metre-long northern tunnel section. The "Haitian" Mixshield, on the other hand, is being used for the 3,255 meter long southern tunnel section. It has a length of 142 meters and a weight of 5,166 tons. The 8.14 meter wide "National Signal" mixshield from Herrenknecht is also creating a service tunnel.

Highlights of the two 15.56 meter wide machines are the tool change under atmospheric pressure, an extendable telescopic main drive, the monitoring system of the excavation chamber and the excavation container, as well as the concept of a short screw conveyor used in combination with a stone crusher box and a stone crusher. This effectively reduces the risk of stagnation in the excavation due to slag and rock. 

This is because the planned tunnel section is subject to complex geological conditions with soft layers in the upper section and hard layers in the lower section in combination with hard rock and fault fracture zones.

The maximum depth of the main tunnels is 95 meters. The machines can withstand sea pressure up to a static pressure of 12 bar.

The "Jiaozhou Bay 2nd Tunnel" is part of a major project of the city of Qingdao as part of the 14th five-year plan. A new highway network is to be built in seven horizontal and nine vertical sections. The project is scheduled for completion and opening to traffic at the end of 2027.