A method of twisting and pulling up and removing pile foundations of offshore platforms

Abstract

The invention provides a method for removing a pile foundation of an offshore platform by twisting and pulling up, and belongs to the technical field of offshore platform demolition construction. It avoids the disadvantages of difficult, high risk, and long construction period for underwater cutting of pile foundations, and quickly and effectively removes offshore platform pile foundations on the water surface. In this demolition method, the offshore tug applies torque to the top of the pile through a long horizontal beam, and the crane on the tug applies a vertical upward pulling force to completely pull out the entire pile foundation. The method of the invention utilizes the principle of leverage to significantly reduce the applied torsional force, and at the same time, the applied torque and uplift force reduce the pullout bearing capacity of the pile foundation. The method of the invention comprises the following steps: A. the tugboat is connected to the top of the pile foundation through a horizontal rigid beam; B. applying a torsional moment on the pile top; C. applying a vertical pulling force on the pile top. This dismantling method has the advantage that the pile foundation can be completely pulled out under a small pulling force.

Description

technical field [0001] The invention relates to a technical method for dismantling an offshore platform, in particular to a technical method for dismantling a pile foundation of an offshore platform. Background technique [0002] At present, there are hundreds of jacket offshore platforms in my country's sea area, and these platforms have made important contributions to my country's offshore oil exploitation. With the expiration of the service period, the platform will be discontinued and discarded. In accordance with international practice and national laws and regulations, the abandoned platforms must be dismantled. International regulations favor the complete dismantling of the jacket, which requires that the pile foundations of abandoned offshore platforms should be cut 4m below the mud surface of the seabed. The removal of the jacket pile foundation is the longest and most expensive project in the entire offshore platform removal process. Regardless of the demolition...

AI Technical Summary

Problems solved by technology

The underwater cutting method is very limited, the operation is difficult and the risk is high, and it takes a long time to complete a cutting underwater, which can reach more than ten or twenty hours, which is prone to engineering problems

[0003] In order to quickly and effectively remove the pile foundation of the offshore platform and avoid the disadvantages of difficult operation, high risk and long construction period of the underwater cutting operation, this patent proposes a method for removing the pile foundation of the offshore platform by twisting and pulling up

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