On October 26, after more than 800 days and nights of continuous effort, the right tube of the Nagu Tunnel, part of the Huize-Qiaojia Expressway project, was successfully holed through. The tunnel is one of the control works of the Huize-Qiaojia Expressway and the first extra-long tunnel in the project to be holed through, marking a phased victory in the tunnel construction of the Huize-Qiaojia Expressway project and taking the overall construction of the project to a new level. It also lays a solid foundation for holing through the left tube of the Nagu Tunnel next month and for the construction of the project's main works.

The Nagu Tunnel adopts a separated structure type and is designed with left and right tubes. The left tube is 3,867 meters long and the right tube is 3,826 meters long, with a maximum buried depth of 682.9 meters. The tunnel passes mainly through dolomite, in a tectonic karst erosion mid-mountain landform. The terrain at the entrance and exit sections is relatively gentle, with natural slopes of 20 to 30 degrees, and the terrain is highly undulating.

Since construction began in May 2021, the Huize-Qiaojia Expressway project has adhered to a high starting point, high-level construction and high-requirement management, with scientific deployment and meticulous organization, steadily advancing preliminary work such as the preparation of construction plans. It has overcome the harsh construction environment and carried out careful planning in many aspects, including construction planning, resource allocation, safety assurance, construction plans and technical discussions. At the same time, it has effectively overcome the special regional environment by actively maintaining continuous communication with the design unit, local government, local villages and other units regarding local customs, the ecological environment and geographical location, striving to create a favorable external environment and fully ensuring that tunnel construction proceeds smoothly under the premises of safety, environmental protection, quality, harmony and civility.

To ensure tunnel construction safety and controllable quality, tunnel construction was carried out in strict accordance with the excavation principles of "short advance, weak blasting, strong support, frequent measurement and timely lining," promptly adjusting excavation methods and support parameters according to the surrounding rock, monitoring and measurement, and advanced geological forecasting conditions on site, and strictly carrying out construction operations in accordance with "standardization" requirements. A combination of on-site presence and remote monitoring management was used to keep abreast of conditions at the construction frontline, and new processes and new equipment were continuously introduced during the process. The "eight major systems," the safety production "clairvoyance" and "safety management with a single mobile phone" and other new equipment and new management methods adopted in the Nagu Tunnel have overall improved the project's on-site safety and civilized construction management level. In addition, ideological education was provided for personnel entering the site so that everyone understands the quality requirements and standards and the key points of safety and environmental protection, attaching importance to them ideologically. Project posts and responsibilities were assigned in place, responsibilities and obligations were clarified, and assessment, reward and punishment systems were established. In handling major issues such as quality and safety, the principle of "fast, clear and serious" was always adhered to, eliminating problems in the bud.