Bridges and tunnels connect, piercing mountains and crossing rivers. Whether driving on the high-cold grasslands of northwestern Tibet or in the southeastern Tibetan valleys, the changes brought by smooth roads are deeply felt. In Tibet, bridges and tunnels for highways and railways span vast distances, accelerating the flow of people, goods, and information, activating the popularity and economic vitality of the 'Roof of the World,' and awakening the frozen plateau.

In June this year, the Lhasa-Nyingchi Railway was completed and opened to traffic, with 47 tunnels and 121 bridges along the entire line, and 130,000 builders working for more than 6 years. In July 2011, the Lhasa-Gonggar Airport Expressway was completed and opened to traffic, ending the history of no expressways in Tibet. Starting in 1950, 110,000 military and civilian personnel painstakingly built the Sichuan-Tibet Highway (formerly the Kangding-Tibet Highway), with a total of 597 bridges and 2,860 culverts, and more than 2,000 people sacrificed.

Behind this is the nation's determination and will to open up roads to and from Tibet. Data from the Tibet Autonomous Region Department of Transportation shows that during the 13th Five-Year Plan period, Tibet completed 251.6 billion yuan in fixed asset investment in transportation, 3.7 times that of the 12th Five-Year Plan period, accounting for one-third of Tibet's total fixed asset investment. The region's highway mileage reached 118,800 kilometers, creating a plateau miracle of an average annual increase of 8,100 kilometers.

Every summer is the golden period for engineering construction on the snowy plateau. The reporter recently saw that the Nagqu-Yangbajain section of the Beijing-Tibet Expressway, which is about to be completed and opened to traffic, is undergoing final procedures such as painting markings and safety inspections.

The Nagqu-Yangbajain section of the Beijing-Tibet Expressway is 226.9 kilometers long, with a design speed of 120 kilometers per hour, and a total of 145 bridges, including 7 extra-large bridges. The 1,025-meter-long extra-large bridge over the Qinghai-Tibet Railway stands on the grasslands of northern Tibet, with trains on the Qinghai-Tibet Railway passing underneath.

Building bridges and tunnels on the plateau faces construction challenges such as high ground temperatures, strong rock bursts, and water inflow.

Recently, various construction units are stepping up the construction of the Lhasa-Shigatse Airport Expressway. The highway starts from Xierong Village, Qushui County, Lhasa City, and ends at Nianmu Township, Sangzhuzi District, Shigatse City, with a total length of 166.75 kilometers.

The Padang Mountain Tunnel on the Lhasa-Shigatse Expressway, undertaken by China Railway 21st Bureau Group, presents great challenges to builders due to high altitude and complex geological structures. 'We overcame difficulties such as tight supply of construction materials and complex geological conditions, adopted 3D laser scanning detection technology to efficiently monitor construction quality; in blasting construction, the depth of each blast hole does not exceed 1.5 times the arch frame spacing, advanced anchor rods were strengthened to 42 advanced small pipes with cement mortar injection, and locking foot anchor rods were strengthened to 42 small pipes with cement mortar injection to ensure safety and order,' said Wang Bo, a person in charge of the Lhasa-Shigatse Expressway project of China Railway 21st Bureau Group.

The Bayu Tunnel on the Lhasa-Nyingchi Railway in Shannan City is called by builders the 'tunnel where stones fly like cannonballs.' During construction, the maximum ground temperature reached 47 degrees Celsius, and the rock burst area accounted for 94% of the tunnel. Rock bursts were intense and frequent, generally lasting 2 to 6 hours, with the longest lasting more than a week, and even secondary rock bursts occurred several months after the initial rock burst, which is very rare in the history of tunnel construction worldwide.

Short effective construction periods and high labor demand are common characteristics of engineering construction in Tibet. Tibet's bridge and tunnel construction has driven more farmers and herdsmen to work and earn income.

The reporter recently saw at the construction site of the Zhongcai Mountain Tunnel undertaken by China Railway Sixth Bureau Group in Lhasa High-tech Zone that workers were carrying out final procedures such as water supply and drainage engineering, lighting installation, and slope treatment. Twenty-year-old Tenzin Sonam from Duoque Township, Nagarze County, Shannan City, was busy mixing cement and arranging stones with his coworkers. 'We earn 230 yuan a day working here, with food and lodging included. More than 20 people who came together are all from Shannan. In recent years, there have been many projects in Tibet, and we have more and more ways to earn money through work.'

According to Yu Haibo, project manager of the Zhongcai Mountain Tunnel project of China Railway Sixth Bureau Group in Lhasa High-tech Zone: 'We provided jobs for 241 local laborers, and also gave priority to using farmers' and herdsmen's machinery and transport vehicles, renting a total of 150 construction machines.'

Today, the Tibetan people enjoy the convenience brought by bridge and tunnel construction.

Fifty-six-year-old Qimei is a villager from Gangtuo Village, Gangtuo Town, Jiangda County, Qamdo City, Tibet, and has been engaged in cargo transportation for nearly 20 years. 'For so many years, what I worried about most every winter was passing through Aila Mountain. The mountain is high and the road dangerous, and there are often falling rocks,' he said.

The Aila Mountain Tunnel, at an altitude of 3,970 meters, is known as the 'First Tunnel in Eastern Tibet.' It was completed and opened to traffic in October 2018, shortening the driving time over Aila Mountain from more than an hour to less than 10 minutes. Qimei said that now he can make a round trip from the township to Jiangda County in the same day, which is not only convenient and safe but also saves transportation costs, with an annual income of about 150,000 yuan.

Farewell to the 'long and arduous journey' across vast distances. Over the past 70 years, Tibetan farmers and herdsmen have gradually escaped the travel predicament of climbing mountains and carrying loads on human backs and animal backs. This witnesses the indomitable spirit of the craftsmanship of a great nation, and the bridge and tunnel construction across the snowy plateau has built more 'unity lines' and 'happiness roads.'