At 11 a.m. local time on September 10, Georgia, in the Gudori Mountains at the southern foot of the Caucasus Mountains at an altitude of 2,000 meters, Chinese builders completed the on-site assembly of the world's largest diameter full-section hard rock boring machine (TBM) "Caucasus" in three months, and successfully launched the road tunnel from Kvesheti to Kobi section of the Georgian North-South Corridor (referred to as "KK Highway Tunnel") constructed by China Railway Tunnel Bureau, marking the "Belt and Road" key transportation project has entered the TBM rapid construction stage.

▲Georgian Prime Minister Irakli Garibashvili attended the event

The traffic is rushing, and the bad climate ushers in a solution

Georgia's North-South Corridor Highway is an important passage connecting Russia, Georgia, Armenia, Azerbaijan and other countries, the Gudoli Mountains in the middle of the route have frequent snowfall in winter, the average annual temperature is lower than 5 °C, and snowfall often causes traffic interruptions, up to more than 20 days, causing great inconvenience to regional transportation.

▲ The night assembly site of the "Caucasus".

The KK Highway Tunnel (Kvysheti to Kobe) constructed by China Railway Tunnel Bureau is located in Mtskheta - Mtianeti Oblast in northern Georgia, and mainly includes a 9-kilometer-long main tunnel and emergency tunnel. The tunnel, which passes through the base of the Gudoli Ridge, will shorten the original travel distance from the existing 35 km winding road to 12 km straight road, and the travel time will be reduced from 1 hour to 20 minutes.

Chinese standards, Chinese design creates the world's largest

　　此次成功始发的“高加索号”TBM应用于KK公路主隧道施工，由中铁隧道局和中铁装备集团联合研制，采用中国设计、中国标准，由中方独立制造。直径为15.08米，是目前世界最大直径TBM，全长182米，总重量3900吨，最大推力2.26万吨，总功率9900千瓦。研制团队首次在硬岩掘进机上采用了同步掘进拼装技术，并配备了主动铰接、双向旋转刀盘、双速减速机等针对性设计，能够实现主机姿态的精确调整和不良地质条件下的快速脱困。

　　漂洋过海，翻山越岭冲破重重阻碍

▲“高加索号”TBM部件通过古多里山区

　　“高加索号”TBM在中国制造完成后，经过拆解，分部件运往格鲁吉亚。首批部件于2020年冬季自上海港启航，途径太平洋、印度洋、红海、地中海、黑海，于2021年1月到达格鲁吉亚波季港。受冬季降雪导致的常态化封路、间断通行等影响，后续部件迟迟难以顺利抵达。

▲“高加索号”TBM部件通过防雪崩隧道

　　中铁隧道局、中铁装备集团组织多方优势资源，克服了临时便道路窄弯多、桥梁老旧承载力不足、防雪崩建筑群限高限宽等诸多困难，先后四次对格鲁吉亚境内运输道路进行现场勘察，并对部分路段采取加固维护和修建临时便道等措施。在卡脖子路段古多里山1号防雪崩隧道，建设者两次进行模拟运输，确保了超重超宽、直径近8米的TBM主轴承顺利通过。

The KK Highway Tunnel is the largest single infrastructure project under construction in Georgia, which will greatly improve the traffic efficiency and driving safety of the North-South Corridor after completion, strengthen its important geopolitical and economic and trade status as a Eurasian crossroads, and effectively promote tourism, employment and border trade in the north and south of Georgia.