On August 30, the left tube of the Guihua Extra-Long Tunnel on the Lexi Expressway was successfully holed through. With this, the Guihua Extra-Long Tunnel, invested in by Sichuan Expressway Company of Shudao Group and constructed by Sichuan Road & Bridge Group, has achieved double-tube breakthrough, marking a breakthrough progress in the Lexi project construction and laying a solid foundation for the full opening of the Lexi Expressway in 2025.

Breakthrough site

The right tube of the Guihua Tunnel was the leading tube and was holed through in April this year. The left tube of the Guihua Tunnel has a total length of 4916 m. To accelerate construction progress, two additional working faces were added to the left tube through cross passages for vehicles, and breakthrough was achieved before the end of August as scheduled. The Guihua Tunnel has harsh construction conditions, with high requirements for environmental protection and soil and water conservation. The project is characterized by "five zones and three lacks." In the early stage of construction, it faced enormous challenges of no access road, no communication signal, and no power supply. All participating parties adopted scientific measures and invested substantial resources and funds, including building about 32 km of construction access roads, installing 4 temporary communication base stations, and erecting 38 km of permanent and temporary power lines. It took nearly two years to achieve normal construction conditions at the entrance and exit of the Guihua Tunnel.

The Guihua Tunnel is an extra-long separated tunnel with small clear distance, constructed by excavating from the entrance and exit ends toward each other, passing through fault zones and karst areas. During construction at the entrance end, roof collapse of connected dissolution pipes occurred nearly 7 times; the exit end was constructed on a reverse slope, with maximum daily water inflow reaching 10,000 m³. The construction conditions are harsh, safety risks are high, and prevention and control are difficult. During construction, all participating parties strictly implemented the concept of dynamic tunnel design modification, promptly adjusted and optimized the design and construction plans, and, in accordance with the requirements of Shudao Group's "Work Promotion Plan for Intelligent Construction of Expressway Tunnels," deployed intelligent machinery and equipment such as intelligent arch-anchor trolleys, double-arm rock drills, and wet spraying manipulators, realizing a new mode of intelligent tunnel construction with fewer workers. At the same time, systems such as work safety and tunnel shift supervision management were strictly implemented, achieving safe breakthrough.

The smooth double-tube breakthrough of the Guihua Tunnel has achieved vertical connection between the S1-8 project management department of the Lexi Expressway and the two work areas. The travel time from the exit end to the entrance end of the Guihua Tunnel has been shortened by more than one hour, greatly improving project management and the efficiency of comprehensive resource allocation between the two work areas. It also provides a convenient channel for the transportation of materials and equipment for the Lexi project, opening up a new situation for pavement and subsequent construction.