Recently, the world's largest diameter full-face hard rock tunnel boring machine "Caucasus" jointly developed by China Railway Hi-Tech Industry and China Railway Tunnel Group, broke through the 5000-meter mark in the construction of Kvesheti-Kobi Highway Tunnel in Georgia's North-South Corridor, reaching 56.4% of the total mileage, and more than half of the excavation task was completed.
For the first time, the R & D team adopted the synchronous tunneling assembly technology on the hard rock roadheader. The "Caucasian" TBM has an excavation diameter of 15.08 meters, a total length of 182 meters, a total weight of 3900 tons, and a maximum installed power of 9900 kilowatts. It is equipped with targeted designs such as an active hinge, two-way rotary cutter head, and double-speed reducer, which can realize the precise adjustment of the main machine attitude and the rapid extrication of difficulties under adverse geological conditions to ensure the efficient tunneling construction of the equipment.
The total length of the main tunnel section of the Georgia North-South Corridor KK Highway Project is 9068 meters. Since the "Caucasian" TBM was excavated in September 2021, the team of China Railway Tunnel Group has made scientific management and reasonable organization, overcome the geological factors such as weak soil layer, toxic and harmful gas surge, groundwater development, and the long construction period in winter in alpine areas, and achieved the highest TBM footage of 20 meters per day and 420 meters per month.
