Recently, the 251st ring segment assembly of the left line shield tunnel between Gangkoucun Station and Dingjiazui Station of Wuhan Metro Line 12 was completed, marking the completion of the excavation and support of the most challenging rock section of Line 12, which was constructed by China Railway Seventh Group Co., Ltd, and creating a new case of hard rock excavation by earth pressure balance shield machine in the domestic metro.
As Asia's longest subway loop line, Wuhan Metro Line 12 passes through three towns in Wuhan, 59.9 kilometers, not only through rivers and lakes but also through complex underground rock and soil layers. Because of the different rock strengths, the requirements for shield tunneling construction are strict. The left line of the shield tunnel between Gangkoucun Station and Dingjiazui Station of Metro Line 12 in Hanyang District is 1244.9 meters long, of which the 63-meter, 251-MPa high-strength quartz sandstone section is a "hard bone", and the construction is similar to "drilling holes on steel plates".
