On April 2, the Leijiashan Tunnel on the Sangzhi-Longshan Expressway in Hunan Province—the longest under-construction expressway tunnel in the province—was successfully holed through. The tunnel was invested in by China Railway Communications Investment Group Co., Ltd. and constructed by China Railway No. 5 Engineering Group Co., Ltd., marking major progress in the construction.

　　The Leijiashan Tunnel of the Sangzhi-Longshan Expressway is located in Sangzhi County, Hunan Province, with a total length of 6.506 kilometers. It is designed as a separated left-and-right tube tunnel and is a controlling, major and difficult project of the entire line, as well as the longest under-construction expressway tunnel in Hunan Province. The tunnel passes through multiple fault zones, with developed karst geology and abundant groundwater. Class IV and V surrounding rock accounts for 85% of the total, and adverse geological conditions such as slight gas and rockbursts are present, resulting in high safety risks and great construction difficulty.

　　Since construction began on March 1, 2021, the Civil Engineering Section 3 project department of the Fifth Company of China Railway No. 5 Engineering Group has earnestly implemented the relevant requirements of the Hunan Provincial Department of Transportation for a “Safe and Centennial Quality Project,” focused on “efficiency improvement and value creation,” adhered to full life-cycle management, systematically advanced integrated whole-process management and control of the project's “investment, construction and operation,” and actively promoted standardization of construction management. It has consistently adhered to the control objective of “planning in advance, leading with models, strict process control, and achieving excellence in one pass,” implemented a new construction organization model of “mechanization replacing workers and automation reducing personnel,” introduced for the first time complete sets of large machinery operations, and developed twelve practical and innovative types of tooling. As a result, the cycle operation time was reduced by an average of about 36%, personnel was reduced by about 28%, and the average monthly advance was increased by about 37%. The monthly advance in Class IV surrounding rock exceeded 150 meters, laying a solid foundation for holing through the entire contract section.

　　It is reported that the Hunan China Railway Sangzhi-Longshan Expressway is an important high-speed major corridor in northwestern Hunan Province, playing an important role in connecting north and south and linking east and west. It starts at the Sangzhi West Interchange in the east and ends at the Maoping Hub in the west, with a total length of 61.494 kilometers. It is a two-way, four-lane expressway with a design speed of 100 kilometers per hour. It is one of the “six vertical and seven horizontal” expressway networks built across Hunan Province's 122 counties and urban districts, and is a major infrastructure project and important livelihood project in Hunan. Once completed, the Sangzhi-Longshan Expressway will be of great significance for opening up interprovincial corridors among Hunan, Hubei, Chongqing and Sichuan and for promoting the development of the western Wuling Mountain area.