Road engineers find inspiration in car parks to conquer western Chinese terrain

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By CGTN's Yang Wentao and Zhu Qinliang

High mountains and deep ravines make the terrain in western China extremely dangerous and challenging. They also pose a challenge to road engineers, who must undertake lengthy studies to determine the best routes along the rivers and mountains.

Winding roads are bad for both efficiency and the environment, while sharp bends can be a nightmare for drivers. The solution is to make the roads straight by tunneling through mountains and bridging rivers.

Mu Tingmin, deputy general engineer at the Sichuan Institute of Road & Bridge Design, said 85% of the highway is bridges and tunnels. There’s barely any regular roadbed.

Crossing the Hengduan Mountains is a tough journey. /CGTN Photo

The Ya'an–Xichang Highway, after starting in the Sichuan Basin, has to cross the Hengduan Mountains, a 3,000 metre-high natural barrier. It used to take 10 hours to cover the 300-kilometre route by car. The engineers have decided to drill straight through the mountains.

A rise of 500 metres over a 4-kilometre distance creates a 9% incline on average. This would pose a real danger to loaded trucks. The engineers had to rack their brains for a way to reduce the angle.

The Ya'an–Xichang Highway /CGTN Photo

Mu Tingmin said, “We borrowed the idea from the spiral ramps in car parks. They allow cars to climb steadily. We built spiral extensions. Vehicles pass through a tunnel and then over a bridge in each spiral ramp. Each spiral rises 120 metres, helping to overcome the steep gradient.”

The Ya’an to Xichang highway is expected to cut travel time in half and become a vital artery in southwestern China.

1645km