New triple-circular pipe roof machine from CRCHI

CRCHI said that it can provide a solution for, “worldwide projects with complex geological conditions and super-large tunnel face pipe roofing.” Image: CRCHI

The Sanya Estuary Passage Project is a critical link connecting Sanya Central Business District (CBD) on the southern end of China’s Hainan Island and the Phoenix Coast Unit via an undersea tunnel.

The tunnel, with a cross-section of 18.4m by 18.4m, will be constructed by using 12 pipe roof sections serving as both temporary support and permanent structure.

The project features water-saturated strata, primarily traversing quartz sandstone, fault breccia, gravelly sand, and silty clay. With upper soft layers overlying extremely hard rock formations, the project exhibits high compressive strength.

To overcome these engineering challenges, CRCHI developed a what it describes as a, “Pilot-tube Guided, Multi-segment Pipe Jacking” construction method for combined circular pipe roofing.

The equipment adopts several key customised technologies, including a multi-posture freely combinable machine, a multi-angle adaptive portal thrust system, a high-precision combined guidance and deviation correction system, and a special-shaped combined portal sealing system. The successful implementation is said to significantly improve construction efficiency and reduce operational risks.

The development of this equipment, spanning four years from research to production, has achieved breakthroughs in multiple cutting-edge technologies. CRCHI said that it can provide a solution for, “worldwide projects with complex geological conditions and super-large tunnel face pipe roofing.”