The nation's first dual-mode shield tunnel section to complete in-tunnel mode conversion, and the only dual-mode shield tunnel section of Power Construction Corporation of China—the Huaide Station to Fuyong Station shield tunnel section of Shenzhen Metro Line 12 (hereinafter referred to as the Huaifu section)—has successfully achieved its double-line breakthrough, marking the full breakthrough of the shield tunnel sections in Civil Engineering Section 6 of Shenzhen Metro Line 12.

The tunnel section from Huaide Station to Fuyong Station is located in Bao'an District. The line environment is complex, passing beneath mountains and numerous buildings and pipelines. The section starts at Huaide Station, runs along Huaide South Road, passes through Wangniuting Mountain, and then follows Fuzhou Avenue to Fuyong Station. The right line is 1,716 meters long, with 1,130 meters passing through slightly weathered granite with hardness exceeding 120 MPa.

Facing the construction challenges of dual-mode shield machines tunneling in complex strata, the company actively integrated existing resources at the work site, including personnel, machinery, and materials, and followed the guiding principles of "coordinated planning, balanced production, priority to key sections, segmented organization, highlighting difficulties, and orderly advancement" in construction organization. In the early stage of construction, the company repeatedly engaged experts to scientifically verify the construction plan, ensuring the applicability of construction techniques and equipment. During construction, daily tunneling analysis meetings were held to promptly analyze the day's tunneling data, adjust tunneling parameters, and advance scientifically. In addition, continuous operations were organized on site through Party member vanguard posts and youth commando teams, ensuring smooth construction progress.

To better meet on-site construction requirements for the dual-mode shield, the company actively adopted measures such as improving the cutterhead opening ratio, adding an in-tunnel advanced drilling system, adding a domestically advanced online cutter monitoring system, and improving the central belt rotation system. To solve the dust problem during TBM-mode tunneling, the shield machine was also equipped with an integrated dust removal system, and compressible flexible air ducts were installed at the drive box position to promptly deliver fresh air to the soil chamber and extract dust to the dust removal machine, forming a microcirculation and providing a comfortable construction environment for workers.

The successful double-line breakthrough of the Huaifu dual-mode shield tunnel section has once again laid the foundation for the scheduled opening and operation of Shenzhen Metro Line 12 in 2022.