On June 20, as the cutterhead of the "Pioneer" pipe jacking machine slowly broke through the last 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 is 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 are basically complete, while the "roadblock" in the expressway's construction—the Wangjiazhai Tunnel, with a total length of 8,040 meters and a maximum burial depth of 1,022 meters—has become the only tunnel on the entire highway that has not yet been holed through due to extremely complex geological conditions, and is known as the "bottleneck control project."

The successful implementation of the new-quality technology of in-tunnel pipe jacking drainage 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.