Recently, the downline of the Dayuan Station–Taihe Station section (the "Datai section") of the Guangzhou South Station–Baiyun Airport section of the Guangzhou–Foshan Intercity Railway (the "Guangfo East Ring Intercity") was holed through, marking the safe and smooth completion of the longest shield tunnel on the entire Guangfo East Ring Intercity line. To date, 93% of the line's civil works has been completed.

The Datai section of the Guangfo East Ring Intercity is a controlling project for the entire line. Its downline is 6,148 meters long, with a tunnel outer diameter of 8.8 meters, an inner diameter of 8 meters, and a ring width of 1.8 meters. The downline shield tunnel was built in a complex geological environment, with a tunnel depth ranging from 12 to 158 meters, abundant groundwater, and ultra-high water pressure (the maximum water pressure during construction and operation exceeds 1.2 MPa, the highest in China to date). During construction, it faced numerous challenges, including long-distance excavation through rock strata, crossing eight fault fracture zones, multiple weathered perched-water troughs and boulders, passing beneath or alongside reservoirs, large-diameter high-pressure gas pipelines, municipal roads, expressways, railways, more than 80 buildings and structures, and water wells intruding into the tunnel body.

The two ends of the downline tunnel in the Datai section consist of 2,539 meters and 1,185 meters of mixed ground, with a 2,424-meter full-face hard rock section in the middle. The 6,148-meter tunnel has no intermediate shaft, and the shield was driven in a single-head excavation, making equipment selection extremely complex. After full communication with the design unit, shield manufacturer, well-known domestic experts, and others, the contractor proposed and successfully applied the "single-shield and earth-pressure-balance dual-mode TBM construction and mode-conversion construction method," which has been widely recognized by relevant practitioners and experts. It resolved the difficulty of the 6,148-meter-long Guangfo East Ring tunnel having no space for an intermediate shaft, enriched the existing dual-mode shield construction technology in China, and provides an important reference for subsequent intercity railway tunnel projects and similar projects in China.

The smooth holing-through of the downline in the Datai section of the Guangfo East Ring Intercity project provides effective excavation parameter references for the shield driving of the upline, marking a further step toward the goal of holing through all tunnels on the Guangfo East Ring line.

The Guangfo East Ring Intercity project starts at Guangzhou South Station, passes through Panyu District, Huangpu District, Haizhu District, Tianhe District, and Baiyun District, and ends at Zhuliao Station. It has eight stations in sequence: Dashi Station, Science Center Station, Pazhou Station, Financial City Station, Smart City Station, Longdong Station, Dayuan Station, and Taihe Station. The main line is 46.7 kilometers long. At present, 93% of the line's civil works has been completed. The main structures of all eight stations have been completed, and ancillary structure construction is underway. Of the nine sections, seven have been holed through (13 of the line's 16 shield machines have safely emerged).