Development and Application of Large Curved-Shaped Pipe Roofing Method with Rectangular Jacking Machine Under the Yangtze River

Abstract

In order to achieve a no-touch and micro-damage salvage under the Yangtze River, a novel underwater wreck salvage method using the large curved shape pipe-roof with rectangular jacking machine (called the CPRJ method in the next study) was proposed. In this study, the feasibility, critical construction parameters and practical application of the novel method were discussed from the equipment, experiment, and on-site construction based on the ancient wreck salvage project named the ‘Yangtze River Estuary II’. The reduced-scale model test (1:10) effectively confirmed the feasibility of the CPRJ method, and the clearance between the locks was controlled to around 2 mm. In the full-scale model test (1:1), an embedded rectangular jacking machine ahead of the pipe section and a combination of the oil motor, gear, and rack in the propulsion system were used. Notably, the propulsion time of a single pipe section can be controlled to about 4 h and the thrust force to less than 1500 kN. In the on-site salvage construction, 22 pipe sections were propelled at a thrust force less than 1000 kN and a locking clearance within 10 mm. The CPRJ method was well validated in the ancient wreck salvage project.