The steel pile foundation of an offshore jacket structure was cut under water, an underwater adjustable leveling cutting tool is designed to match the abrasive water jet cutting process for high-level cutting operations. It solves the levelness requirements of the steel pile foundation underwater cutting and the relative height difference requirements of the four steel piles. The final cutting accuracy reached a single pile level ≤1%, the relative elevation of the four steel piles was <50mm, and the level of the new jacket after installation was 0.96‰.
During the construction of the jacket, it may happen that the steel piles are not in place or the top elevation of the steel piles does not meet the design requirements and is difficult to solve by re-driving. In this case, steel pile cutting is the fastest and safest process. In the construction of ocean engineering, the underwater cutting processes for steel piles with larger wall thickness and higher precision include diamond wire saw cutting, abrasive water jet cutting and new underwater laser cutting technology (Gong, 2016; Sun et al., 2013; Wang et al., 2015; Wang et al., 2019), no matter which cutting process, adaptation tooling is the key equipment, and its adjustment accuracy is related to the underwater cutting accuracy. At present, domestic laser underwater cutting is still in the laboratory verification stage (Wang et al., 2020), and there is little engineering practice. The diamond wire saw cutting machine is affected by its structural size, and has certain requirements for the diameter and structure of the steel pipe pile to meet the construction process (Wang et al., 2016). The abrasive water jet cutting equipment is equipped with reasonable tooling for high-precision underwater cutting, which makes it easier to realize the operation process. Underwater cutting of the steel pile foundation of a jacket structure, focusing on controlling the level of steel pile cutting and the relative elevation of the four steel piles. For the purpose of this operation, an underwater adjustable leveling cutting tool is designed to match the abrasive water jet cutting process for high-level cutting operations.
