Dejiang Tunnel, Dejiang to Wuchuan Section of the Dejiang to Xishui Expressway in Guizhou Province

Project Overview:

The Dejiang Tunnel is the most critical and controlling project along the Dejiang to Wuchuan section of the Dejiang-Xishui Expressway in Guizhou Province. The left tube of the Dejiang Tunnel has a total length of 5,505 meters, while the right tube measures 5,425 meters. Dubbed “Guizhou’s Most Challenging Highway Tunnel,” it boasts the most complex hydrogeological conditions within the province. The tunnel was completed and opened to traffic in January 2021, with a total estimated investment of approximately 787 million yuan. During construction, the tunnel encountered peak water inflow rates as high as 600,000 cubic meters per day and maximum water pressure reaching 2 megapascals—figures that are the highest ever recorded for similar tunnels in China. The volume of water inflow could fill the entire West Lake in just 50 days. The complexity of its groundwater hydrological system and the extreme difficulty of its construction are truly rare on a global scale. During the design phase, a series of innovative technologies were employed, successfully overcoming the challenges associated with constructing a highly water-rich karst mountain tunnel and achieving a harmonious coexistence between the project and the exceptionally complex hydrological environment. Building upon this project, advanced techniques for treating water inflows in high-pressure, water-rich karst highway tunnels have been developed, filling a significant gap in the industry’s technical knowledge and providing crucial support for the formulation of standards such as the "Technical Specification for Grouting and Sealing of High-Pressure Karst Water Inflows in Tunnels." These efforts have powerfully driven technological advancement within the industry.

Project Highlights:

During the design phase, by scientifically optimizing the alignment, the tunnel was routed to traverse the Naoshuiyan underground karst hydrogeological unit over the shortest possible distance, effectively avoiding areas with significant geological hazard risks. As a result, the tunnel’s length was successfully shortened by 30%, saving approximately 600 million yuan in project investment.
During the design phase, a proactive drainage plan was adopted for the long tunnel’s drainage tunnels, effectively addressing the issue of large-scale, concentrated water inflows from karst conduits during construction and thereby avoiding major engineering changes costing tens of millions of yuan that would have been required if additional drainage tunnels had been added.
An innovative multi-level precise drainage and diversion technology—combining “water-collection corridors, tunnel-bottom slab culverts, transverse drainage tunnels, and drainage tunnels”—was adopted to completely address the massive water inflow of up to 600,000 m³/day from large, highly water-bearing karst conduits during tunnel construction, thereby ensuring the safety of both tunnel construction and operation.
An innovative integrated grouting technology has been developed, incorporating advanced techniques such as “high-pressure, high-flow water curtain grouting + advanced and peripheral grouting around injection holes + membrane bag grouting for high-velocity karst water channels + high-pressure air-water replacement grouting for filling-type solution cavities and fractures.” This comprehensive approach has successfully addressed the challenge of water inflow in the synclinal core.
In environmentally sensitive areas, site-specific limited-emission technologies are employed, combining “grouting to seal water sources with centralized drainage and discharge.” This approach not only addresses the challenging issue of large-scale water inflows in through-going sections but also effectively protects the ecological environment of the Naoshuiyan underground dark river basin.

Honored Achievements:

Second Prize, Guizhou Province Civil and Architectural Engineering Technology Innovation Award, 2023;
Special Grand Prize of the Guizhou Provincial Highway Society Science and Technology Award for 2023;
First Prize of the Guizhou Province Mechanics Science and Technology Award, 2023;
First Prize, Guizhou Province Outstanding Engineering Survey and Design Award for 2024;
Second Prize, Excellent Highway Transportation Design Award, China Highway Survey and Design Association, 2025.

Project Showcase: