Recently, as the excavator officially began digging into the tunnel, the tunnel underpassing the Xi'an Outer Ring Expressway of the South Main Line of the Han-to-Weihe River Water Diversion Phase II Project, undertaken by Sinohydro Bureau 3 Co., Ltd., officially commenced construction, marking that the project has entered a new stage of comprehensive acceleration.

The Han-to-Weihe River Water Diversion Phase II Project has been listed among the 150 major water conservancy projects prioritized by the state during the 14th Five-Year Plan period. It is a backbone project of the water conveyance and distribution works, consisting of the Huangchigou water distribution hub, the south water conveyance main line, the north water conveyance main line and their supporting facilities, and is tasked with delivering the diverted Hanjiang River water to 21 water-receiving objects.

The tunnel underpassing the Xi'an Outer Ring Expressway is an important passage connecting the box culvert at the project's inlet section and the main prestressed reinforced concrete pipeline. The mined section of the tunnel has a total length of 108 meters and adopts a circular-arch straight-wall cross-section. It mainly covers engineering operations such as benched excavation of the tunnel, initial shotcrete, installation of steel mesh, and erection of steel frames (with locking foot anchor pipes). Due to the complex geological environment of the mined section and the wide road surface and heavy traffic of the Xi'an Outer Ring Expressway above, construction safety risks are high and settlement control requirements are strict. Facing these challenges, the project team planned ahead and made meticulous arrangements, and plans to adopt the three-bench method, dividing the tunnel cross-section into upper, middle and lower parts for layer-by-layer excavation and layer-by-layer support, thereby effectively reducing the risk of collapse and deformation of the surrounding soil mass.

The project team will carry out the technical disclosure process in a solid and detailed manner, effectively strengthen safety risk control, strictly standardize construction standards, coordinate the above-ground and underground construction, seize the golden period of summer construction, and strive hard for the early breakthrough of the tunnel.