On January 5, 2021, the super-large-diameter hybrid shield machine "Yongping" was successfully rolled off the assembly line in Nansha, Guangzhou. It is understood that the shield machine is a mud-water balance shield machine with a length of 160 meters, a weight of 4,000 tons, and a cutter head diameter of 14.57 meters. After the shield machine is off the assembly line, it will be used in the construction of the Shantou Bay Subsea Tunnel on the Shantou Railway, the world's first sea-crossing high-speed railway tunnel. According to the construction plan, the "Yongping" shield machine will go down at the beginning of the north bank shield tunnel section at the end of March 2021 to begin excavation.

Shantou Bay Subsea Tunnel of Shantou Railway

China Railway 14th Bureau contracted to build the Shantou Bay Subsea Tunnel of the Shantou Railway, located in Shantou Bay, Shantou City, Guangdong Province. It is the world's first high-speed rail subsea tunnel with a design standard of 350 kilometers per hour and a large-diameter cross-sea shield. The total length is about 9.8 kilometers. The length of the shield section is 2,169 meters, including a 40-meter shield air-lift section. The tunnel is divided into sea area section and road area section, and the construction is from the north and south banks facing each other. The mining method is used from the south bank to the north, and the shield method is used from the north bank to the south.

It is reported that the shield machine will traverse 890 meters of soft soil, 430 meters of upper soft and lower hard, and 809 meters of full-face hard rock starting from the launch well. It will traverse 3 fracture zones, a large number of sand sections and boulder sections. Along the line, go under the Zhongtai overpass, Shenhai Expressway, Huaneng Water Plant, and sideways through Jinfeng Food City, high-voltage power tower, underneath Taixing Road and surrounding shanty towns and other structures and then arrive at the sea area section of the dismantling tunnel for drilling Dismantling within.

In order to ensure the normal excavation of the super-large cross-section and high-risk subsea tunnel under the complicated sea conditions by the shield machine, combined with the rich underwater tunnel construction experience of China Railway 14th Bureau, the equipment appropriately increases the opening rate of the cutter head, and installs locks and replaceable hobs for normal pressure. The fixed scraper fixing bolts are designed to be strengthened. For long-distance full-face granite tunneling, the normal pressure composite cutter head with a front hob cutter spacing of 90 mm is adopted, and each normal pressure replaceable hob cutter barrel is installed The hob rotation monitoring system can monitor the rotation and temperature of the hob, so that the cutter can be inspected and replaced in a targeted manner, reducing unnecessary downtime and improving construction efficiency. At the same time, according to the needs of the shield machine to be dismantled in the mining tunnel, the cutter head segmentation and the trolley structure are designed and detailed dismantling plans are formulated to meet the various constructions of the shield tunneling of the Shantou Bay Subsea Tunnel Claim.

In the future, the Shanshan Railway will constitute an important new channel for East Guangdong to integrate into the Guangdong-Hong Kong-Macao Greater Bay Area. By then, it will promote the active integration of East Guangdong's urban agglomerations into the Pearl River Delta, and strengthen the efficient communication between East Guangdong and the Pearl River Delta. Editor/He Yuting