On March 9, with the cutterhead of the 6.6-meter-diameter composite earth pressure balance shield machine on the left line between Guangyuan Xincun Station and Hengfu Road Station slowly breaking through (hereinafter referred to as "Hengfu No. 1"), the longest single-line shield tunnel of Line 12 was successfully broken through, laying a solid foundation for the early realization of the whole line.

The "Hengfu No. 1" shield crosses an area of about 2.15km, the surrounding environment is complex, and 66 buildings have been crossed, among which the Fei'e West Building Group and the Animal Experiment Center of Guangzhou University of Chinese Medicine are major risk sources at the group level. In addition, the shield crossing strata are very characteristic of Guangzhou, mainly limestone, mixed granite and argillaceous siltstone, of which the long-distance crossing of mixed granite is about 1km, and the maximum buried depth of the tunnel is about 66 meters.

In order to ensure the smooth progress of the shield, the project team attaches great importance to it, focuses on the selection of equipment in the early stage, optimizes the shield equipment, organizes experts to optimize the construction plan and plan for many times during the construction process, strictly controls the shield tunneling parameters, strengthens ground inspection and monitoring and measurement, and ensures that the shield machine smoothly passes through various major risk sources.

With the unremitting efforts of all the staff of the project, the left line of the Guangheng section overcame many difficulties and successfully realized the single-line breakthrough of the shield. At the same time, the assembly quality of tunnel segments is good, which greatly enhances the self-confidence and determination of the project department to break through major risk sources, and provides valuable experience for subsequent shield construction.