Yangzhou Dilong NPD4000 slurry balance pipe jacking machine has been successfully deployed on the Henan Section of the Yangtze-to-Huaihe Water Diversion Project, a national key water conservancy project. The machine undertakes trenchless pipe jacking construction for the project’s extra-large-diameter water conveyance pipelines and has smoothly completed tunnelling of large-diameter tunnels, delivering solid equipment support for the efficient construction of this national strategic water allocation project.

As a landmark strategic water conservancy project in China, the Henan Section of the Yangtze-to-Huaihe Water Diversion Project features stringent construction standards and prominent construction difficulties. The project adopts extra-large-size water conveyance pipelines with an inner diameter of 4 meters and an outer diameter of 4.8 meters. The special working conditions for extra-large-diameter construction impose extremely strict requirements on the load-bearing capacity, stratum adaptability, tunnelling stability and construction precision of pipe jacking equipment. Conventional pipe jacking machines fail to meet the construction demands for such extra-large-diameter pipelines.

To satisfy the special construction requirements and high standards for extra-large-diameter works of the Yangtze-to-Huaihe Water Diversion Project, Yangzhou Dilong selected the NPD4000 slurry balance pipe jacking machine well-matched to site conditions. Developed for domestic extra-large-diameter pipeline construction, it was the largest slurry balance pipe jacking machine in China at that time, specially designed for tunnelling pipelines with an outer diameter of 4.8 meters. Equipped with a mature and reliable slurry balance control system, the machine precisely stabilises excavation face pressure, adapts well to large-section tunnelling conditions, and guarantees stratum stability and tunnelling safety during extra-large-diameter construction.

During on-site construction, the NPD4000 slurry balance pipe jacking machine delivered stable overall performance and reliable tunnelling precision, perfectly adapting to the trenchless construction scenario for extra-large-diameter pipelines. It accomplished large-section pipeline tunnelling steadily throughout the construction process and effectively avoided common risks in large-diameter construction including stratum disturbance, alignment deviation and tunnelling stagnation. It fully demonstrated the outstanding performance advantages of large-scale slurry balance pipe jacking machines in major national water conservancy projects and successfully fulfilled all construction specifications of the project.

The successful application of the NPD4000 pipe jacking machine on the Henan Section of the Yangtze-to-Huaihe Water Diversion Project overcomes technical hurdles in the construction of domestic extra-large-diameter water conservancy pipelines and strongly safeguards the construction quality and schedule of the national water project. Going forward, relying on high-end, large-sized trenchless construction equipment and a professional technical service system, Yangzhou Dilong will keep empowering the high-quality development of major national water conservancy works and municipal infrastructure projects, and contribute to improving the national water resource allocation system.