On June 20, as the cutterhead of the "Pioneer of the Path" pipe jacking machine slowly broke through the final layer of rock and soil and successfully reached the receiving shaft, the Wangjiazhai Tunnel drainage pipe jacking project on the Yunnan Lincang–Qingshuihe Expressway, constructed by China Railway Tunnel Group, was successfully completed. This marks China's first successful practice of extra-high-risk, ultra-deep-buried, ultra-high-pressure slurry balance pipe jacking for water and mud inrush in an expressway tunnel, and represents an important innovation in tunnel construction methods.

At present, the main works of the Lincang–Qingshuihe Expressway have been basically completed, while the Wangjiazhai Tunnel—the "roadblock" in the expressway's construction—has a total length of 8,040 meters and a maximum burial depth of 1,022 meters. Owing to extremely complex geological conditions, it has become the only tunnel on the entire highway that has not yet been holed through, and is known as the "bottleneck control project."

The successful implementation of the new-quality in-tunnel pipe jacking drainage technology has become a "new key" to solving the *** construction challenge of the Wangjiazhai Tunnel, and also provides technical guidance and a pioneering solution for similar complex tunnel construction in the future. It is reported that after the pipe jacking holing-through, the Wangjiazhai Tunnel will immediately launch pipe jacking drainage construction, which will greatly improve the tunnel's hydrogeological conditions, ensure safer and more efficient progress of tunnel construction, and lay the foundation for the full holing-through of the tunnel.