On August 28, good news was heard from the Pearl River estuary tunnel of Shenzhen-Jiangmen Railway. The super large diameter slurry TBM 'Dawanqu' independently developed by China Railway Engineering Equipment Group Co., Ltd. (CREG) under CRHIC advanced for 1,000 meters, marking that the shield tunneling construction of China’s deepest submarine tunnel is accelerating.

The Pearl River estuary tunnel Lot 2 project is 2,930 meters long, suffering from extremely complex geology, severe water corrosion in the surroundings, great construction difficulties and high safety risks. CREG tailored a slurry TBM 'Dawanqu' for the tunnel construction. With excavation diameter of 13.32 meters, the machine adopted innovative technologies such as small spacing atmospheric pressure composite cutter head, retractable main drive and ultra-high pressure automatic compensation for smooth advancement in mixed-face ground, which guarantees a safe and efficient tunnel construction. Along the excavation route, the upper soft lower hard ground and full-face hard rock ground have a proportion of more than 60%, with average rock strength being about 70MPa and the maximum strength being 202 MPa.