The Houay Phoulai Tunnel, a highly risky and a key bottleneck project along the China-Laos railway, was drilled through at 9:00 on July 23. Connecting Boten to Vientiane, the tunnel was designed by China Railway Eryuan Engineering Group Co., Ltd, built by China Railway No.8 Engineering Group, supervised by China Railway Academy Co., Ltd., and tested by a third party.   

The 6,969-meter-long tunnel, with a maximum burial depth of 645 meters, goes through an unpopulated zone in northern Laos’ Oudomxay Province. Local harsh geological conditions made its construction highly difficult and risky. To overcome the difficulties and ensure the safety of the construction, the Chinese company had carried out real-time monitoring of gas and other toxic and harmful gases throughout the construction process, adopted a variety of advanced geological forecasting methods, installed more pumping and drainage facilities, and used new technologies to prevent the tunnel from deformation. (By Chen Zuoyi, Luo Renli, Chang Zhenggong and Sun Qiang)