The Shangge village tunnel, the last section of the Yinchuan-Xi’an high-speed railway, was excavated on June 27, marking the completion of the main part of the railway.

An aerial photo shows the entrance of the Shangge village tunnel. (Photo/cyol.com)

The 6.78 km tunnel runs through Dongzhiyuan, the world’s largest loess tableland several hundred meters thick, with subsurface runoff, according to Wei Shaogang, general manager of the project department of China Railway 22nd Bureau Group, the constructor.

The wet loess zone in Dongzhiyuan is rare both at home and abroad. The complex geological situation has brought huge difficulties to the construction of the high-speed railway.

“The loess of the tunnel exhibits a high moisture content of 33 percent, so it is extremely easy for the tunnel to become deformed, causing collapse during construction,” said Wei.

Technicians conduct a safety check the Shangge village tunnel. (Photo/cyol.com)

However, the construction team overcame the world-level geological challenges, finding creative ways to continue construction of the tunnel.

The 618 km high-speed railway, with a design speed of 250 km per hour, is expected to begin service by the end of this year.

The high-speed railway will reduce travel time between Yinchuan in northwest China’s Ningxia Hui Autonomous Region and Xi’an in northwest China’s Shaanxi province to around three hours from the current 14 hours.