The project in south China’s Hainan province will provide a critical link between Sanya’s central business district and the Phoenix Coast Unit.
The undersea tunnel, which will have a cross-section of 18.4×18.4m, will be constructed 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 features high compressive strength.
To meet these challenges, CRCHI developed what it describes as “an innovative ‘pilot-tube guided, multi-segment pipe jacking’ construction method for combined circular pipe roofing”.
The machine, named Lucheng, features 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 of this project will significantly improve construction efficiency and reduce operational risks,” CRCHI says.
It adds that the equipment, which took four years to develop, provides “breakthroughs in multiple cutting-edge technologies, filling critical gaps in the industry. Its successful development provides a pioneering ‘CRCHI solution’ for worldwide projects with complex geological conditions and super-large tunnel face pipe roofing”.
