Recently, the China Highway Society announced the list of “Tunnel and Underground Space Innovation Projects” for 2023. The tunnel complex on both banks of the Lüzhijiang Bridge, designed by Kan She Co., Ltd., won the award in the “Planning and Design Creativity” category.
Since 2022, the China Highway Society has established the “Tunnel and Underground Space Engineering Innovation Award,” specifically intended to recognize China’s most innovative tunnel and underground space projects. The award comprises three categories, among which the Innovative Project in Planning and Design Creativity is designed to honor outstanding projects that feature scientifically sound planning schemes, novel and distinctive design concepts, richly distinctive regional cultural elements, and that actively promote innovation and development within the industry and related sectors. The tunnel complex on both banks of the Lüzhijiang Bridge is the second consecutive time—following the Tencent Tunnel-Style Data Center—that it has been awarded the “Tunnel and Underground Space Innovation Engineering” prize, marking high recognition within the industry of Kanshe Shares’ expertise and technological innovation in underground space design.
The Yuchu Expressway in Yunnan Province crosses the Lüzhi River. On the Yuxi side, the Fenghuang Tunnel is located, while on the Chuxiong side, the Baishiyan No. 1 Tunnel is situated. Spanning between the two banks is the Lüzhi River Bridge, which is the world’s longest single-tower, single-span steel-box-girder suspension bridge. Both anchorages on either bank are tunnel-type anchorages; among them, the tunnel anchorage on the Yuxi side has an exceptionally steep inclination angle of 54°, setting a global record. The coordinated spatial and temporal integration of bridges, tunnels, and tunnel anchorages represents a key challenge in the design of this tunnel complex.
The project innovatively integrated roller-type composite cable saddles into the tunnel anchor caverns within the mountain, achieving the construction goal of eliminating the need for abutments on the sheer-rock side of the suspension bridge. The project also pioneered a “one-tunnel-to-four-cavern” construction method along with comprehensive reverse-excavation technology, enabling zero-grade excavation and exit from the sheer-rock tunnel complex. By comprehensively adopting the “deep inverted arch + no central guide” technique, the project successfully addressed the challenge of constructing abutments on sheer rock, thereby contributing to the successful completion of the world’s first single-tower, single-span steel-box-girder suspension bridge. The participating units of this project developed an intelligent and rapid muck removal system for steeply inclined tunnel anchors as well as a secondary lining trolley specifically designed for steeply inclined anchor caverns, effectively solving the world’s most challenging problem in constructing steeply inclined tunnel anchors—a feat that has been hailed as a “bridge-building miracle.” The project has been extensively covered and interviewed by numerous media outlets, including CCTV, Yuxi Radio and Television Station, and Yuxi News, and its technologies have been widely adopted in major projects such as the Dadu River Super Bridge on the Sichuan-Tibet Railway.
The project’s innovative design has developed a complete set of construction technologies for large-span suspension bridge tunnel anchors and spatially three-dimensional tunnel networks featuring branching tunnels. Several of these innovative technologies are at the forefront domestically, collectively saving the project 200 million yuan in investment. This approach has opened up a new pathway for constructing bridges and tunnels in challenging terrains characterized by steep, sheer cliffs, thereby enhancing China’s core competitiveness in bridge-and-tunnel construction in deep mountain canyons. It represents an outstanding example of a bridge-and-tunnel integrated tunnel network project in China.
