On April 27, the left tube of the Zhebai Tunnel, the longest tunnel on the entire Luoba Expressway, broke through. On the 28th, a tunnel breakthrough observation meeting and the exit breakthrough ceremony were held at the tunnel entrance.

As one of the controlling projects of the entire Luoba Expressway, the Zhebai Tunnel has a left tube 4.939 km long and a right tube 4.932 km long. The breakthrough of both tubes in the exit direction marks a phased breakthrough in the construction of Phase II of the Luoba Expressway.

At the tunnel observation meeting, all participants watched video materials and breakthrough footage on new technologies such as the "layered and window-by-window symmetrical pouring" and "formwork grouting" for the secondary lining, the new water-pressure blasting process, and the hydraulic self-propelled waterproof board hanging trolley. The application of these new processes and methods ensured the safety and convenience of tunnel construction and inspection, reduced workers' labor intensity, improved construction efficiency, decreased the overlap of waterproof boards, and provided better waterproofing. The application of water-pressure blasting technology improved the utilization rate of explosives, improved the working environment, effectively controlled the excess consumption of shotcrete, and increased economic benefits.