On March 26, the left tube of the Jixia Tunnel on the A7 contract section of the Shanan Expressway, constructed by the Third Company of China Railway 14th Bureau Group, was successfully holed through, achieving a breakthrough at a major key milestone.

　　The left tube of the Jixia Tunnel has a total length of 257 meters, with shallow-buried and asymmetrically loaded terrain, where excavation is prone to collapse and instability. The surrounding rock of the tunnel body is mainly Grade V, with Grade V surrounding rock exceeding 90 percent, indicating high risk; it consists mainly of slope residual soil and strongly weathered rock, with considerable thickness, poor geological conditions, and uneven soil quality that softens easily upon contact with water, making the surrounding rock prone to collapse. The tunnel passes through two structural fracture zones, with risks of block falling and collapse.

　　Facing numerous construction challenges, the construction party planned ahead and formulated detailed construction plans during tunnel excavation, conducted technical briefings at every level, defined clear divisions of labor, and assigned responsibilities to individuals. At the same time, through a combination of multiple advanced geological prediction methods, it conducted comprehensive analysis and judgment of geological conditions, identified the location, nature, and scale of unfavorable strata in advance, strengthened ventilation and monitoring of toxic and harmful gases, reinforced monitoring and measurement, and made every effort to overcome difficulties and advance construction.

　　The Shanan Expressway project is a key construction project in Fujian Province and has been included in the national expressway network. After the project is completed, the travel time from Shaxian to Nanping will be shortened from 2.5 hours to within 1.5 hours, which is of great significance for strengthening regional cooperation and complementarity, implementing the rural revitalization strategy, and promoting the revitalization of the old revolutionary base areas and former Soviet areas.