Recently, the right tube of the Huangtupo Tunnel on the Nayong-Qinglong Expressway, constructed by the Road & Bridge Group under Guizhou Communications Construction Group, was successfully holed through, opening up the "key passage" linking Liuzhi Special District and Shuicheng District along the Nayong-Qinglong Expressway and laying a foundation for subsequent pavement construction.

The Huangtupo Tunnel is located within Zhongzhai Township, Liuzhi Special District, and is a small-clearance, separated, large-arch tunnel. The left tube is 3,756 meters long and the right tube is 3,781 meters long, designed as a dual-direction, six-lane tunnel. The Qinglong end of the tunnel connects to the Qingjiao No. 1 Bridge; the working face is situated on a near-90° cliff, where direct portal excavation was not feasible. The original cliff face runs at a 60° angle to the alignment, and the surrounding rock mass is highly fractured, resulting in poor construction conditions, high difficulty, and elevated safety control risks.

The project team adopted a "cantilevered-inverted bamboo cut" portal design to reduce the quantity of slope excavation and protection works, and used a construction adit to assist tunnel entry, changing "entering the tunnel" into "exiting the tunnel" to reduce cut slope excavation. At the same time, the team innovatively proposed, for the first time, an excavation method for extra-high, extra-wide, large-cross-section tunnels in cliff-adjacent sections, and applied it to excavation construction of the Huangtupo Tunnel. This technique replaces the traditional double-side-drift heading construction sequence, resolves the construction difficulties in the "tunnel-over-bridge" section of the Huangtupo Tunnel, and protects the surrounding ecological environment to the greatest extent possible.