At the start of the new year, good news comes from the Greater Bay Area. At 9:30 on January 4, the China Railway Sunward shield machine successfully broke through the left line from Low-Carbon Station to Pingxi Station on Shenzhen Metro Line 3, marking the full breakthrough of both lines in this section.

Facing Difficulties, Forging Ahead

The section is long, the strata are complex and variable, and there are protected cultural relic buildings on the surface. In addition, the project team lacked experience in the launching and receiving of steel sleeves, which greatly increased the difficulty of the project.

The left line of the section has a starting and ending mileage length of 976.748m and a maximum burial depth of 32.7m. The shield machine started from Low-Carbon City Station, and the section needed to pass beneath a karst development area, the Xiao Family Watchtower Site, buildings and structures, rivers, and important pipelines, finally arriving at Pingxi Station, one of the first metro stations in China built with a long-arch large-span assembled structure under an internal support system.

In order to meet the needs of the rapid advancement of Shenzhen rail transit construction, the project team, on the basis of good safety control, pushed detail management to the extreme, greatly ensuring the continuous and efficient progress of shield construction.

The Project Is Difficult, but Morale Remains High

In response to the difficulties of the Xiao Family Watchtower Site, the karst development area, and the uncertainty of the long-distance loose composite strata and underground pipelines, the project team formulated scientific and reasonable shield tunneling parameters, closely monitored the slag samples and slag volume, adjusted technical measures in a timely manner according to real-time tunneling conditions, optimized tunneling parameters, and scientifically applied shield construction methods, increasing simultaneous thickening grouting, middle-shield mud injection, soil chamber polymer improvement, and strict control of secondary grouting, following the dual-control principle of grouting volume and grouting pressure. In particular, the efficient application of low-concentration polymer slag improvement in the soil chamber, middle-shield mud injection, and simultaneous dual-fluid grouting technology effectively prevented settlement of the Xiao Family Watchtower.

When formulating construction parameters, the project team comprehensively considered changes in engineering geological conditions and cover thickness within the scope of dangerous and major projects, and implemented information-based construction based on settlement monitoring data during construction. Based on the principles of high quality and high efficiency, with safety and reliability as the foundation, the project team went all out to achieve the goal of smooth breakthrough of the left line, ultimately achieving a perfect completion.

The smooth breakthrough of the tunnel in the Pingdi section once again demonstrated the dedication of the China Railway Sunward team, who are especially able to endure hardship and especially able to fight. This not only laid a solid foundation for the smooth opening of the entire Shenzhen Metro Line 3 East Extension, but also won a good reputation for the company in the metro market.

In 2023, China Railway Sunward will be fully prepared and go all out to continue contributing to the construction of the Guangdong-Hong Kong-Macao Greater Bay Area.

Sunward Intelligent Official Website