Installation drag reduction method suitable for deep sea suction anchor

Abstract

The invention discloses an installation and resistance reduction method suitable for a deep sea suction anchor, and relates to the technical field of ocean energy. The installation resistance reduction method is mainly characterized in that thin-layer solid lubricating materials are adhered to the inner side wall and the outer side wall of the suction anchor, and therefore the problem that the installation resistance of the suction anchor in a seabed is too large is solved. The lubricating material is a composite material which is difficult to dissolve in water and resistant to high pressure, the thickness of the sticky thin-layer solid lubricating material is gradually reduced from bottom to top, and the problem that the abrasion of the lubricating material is gradually increased along with the increase of the mounting depth can be solved through the thickness setting. According to the installation resistance reduction method for the deep sea suction anchor, the installation resistance of the suction anchor can be reduced, the deeper anchoring depth is achieved, and then the bearing performance of the suction anchor is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of offshore energy platform foundation anchoring and is a construction method suitable for reducing the installation resistance of deep-sea suction anchors. Background Art

[0002] Deep-sea suction anchor is a marine infrastructure installed by negative pressure, which is widely used in floating platforms, submarine pipelines and other projects. Its core principle is to pump out the water in the anchor barrel by pumping, forming a pressure difference between the inside and outside to drive the anchor body into the seabed. However, under complex geological conditions (such as hard clay or dense sand layers), the high friction resistance between the side wall of the anchor barrel and the soil significantly affects the penetration efficiency and even leads to installation failure. Existing studies have mostly reduced resistance by optimizing the geometry of the anchor body, adjusting the negative pressure loading rate or improving the drainage path of the soil, but the effect is limited. Especially in deep-water high-pressure environments, it still faces bottlenecks such as insufficient penetration depth and excessive energy consumption.

[0003] In recent years, the control of interface friction has become a breakthrough direction. Studies have shown that sidewall friction is the main source of penetration resistance, and it is difficult to weaken it in a targeted manner with traditional processes. Inspired by the use of lubricating materials to reduce friction in shield tunnels and pile foundation projects, this study proposes to apply a high-performance lubricating coating on the side wall of the suction anchor to achieve active control of resistance by reducing the shear strength of the soil-structure contact surface. This process combines construction convenience with environmental adaptability, and provides a new idea for the efficient penetration of suction anchors in complex deep-sea strata. Summary of the invention

[0004] In order to solve the above-mentioned technical problem of excessive side wall friction during the installation process of deep-sea suction anchors, the present invention proposes an installation drag reduction method suitable for deep-sea suction anchors, which achieves the effect of reducing the friction between the side wall and the soil by coating a high-performance lubricating coating (solid lubricating material) on the side wall of the suction anchor, thereby reducing the construction cost.

[0005] The technical solution adopted by the present invention to solve the above technical problems includes: pre-treatment of deep-sea suction anchor installation and post-treatment of solid lubricating material adhesion; the pre-treatment of deep-sea suction anchor installation is: pre-arranging micro-rivets with annular spacing distribution on the inner and outer side walls of the deep-sea suction anchor, and then installing mesh cloth on the micro-rivets; the post-treatment of solid lubricating material adhesion is: adhering solid lubricating material on the mesh cloth, and the lubricating material is adhered within the height range of the anchor body and has different thicknesses at different heights.

[0006] Furthermore, the micro rivets are arranged in a ring shape and are evenly distributed on the inner and outer side walls of the suction anchor, and the interval between the micro rivets in each ring is equal to the diameter of the suction anchor.

[0007] Furthermore, the mesh cloth is made of materials such as polyester, polypropylene, and glass fiber to achieve the adhesion of the solid lubricating material; a certain gap is left between the mesh cloth and the side wall of the suction anchor.

[0008] Furthermore, in the post-adhesion treatment of the solid lubricating material, the solid lubricating material can be selected in the form of a graphite / metal composite coating and a ceramic-based self-lubricating material, and a suitable plasticized adhesive is selected for temporary shaping (uniformly adhering to the mesh cloth).

[0009] Furthermore, the adhesion thickness of the solid lubricating material decreases linearly along the height direction of the suction anchor, the maximum adhesion thickness does not exceed 50% of the side wall thickness of the suction anchor, and the minimum adhesion thickness is 5% of the side wall thickness of the suction anchor.

[0010] The beneficial effects of the present invention are:

[0011] 1. By sticking the solid lubricating material on the side wall of the suction anchor, the friction resistance between the side wall of the suction anchor and the soil can be actively reduced.

[0012] 2. The solid lubricating material adopts a new composite material. On the one hand, the solid lubricating material can withstand the high-pressure and low-temperature deep-sea environment and has wear-resistant characteristics; on the other hand, during the installation process, as the depth of soil increases, the solid lubricating material that first contacts the soil will produce wear. Therefore, the thickness of the solid lubricating material is gradually increased from top to bottom in the entire suction anchor depth, which can ensure that the lubricating material continues to play a role during the entire installation process.

[0013] 3. The mesh cloth is made of materials such as polyester, polypropylene, and glass fiber, and has good tensile properties. It can be used as a skeleton for plastic shaping of the solid lubricating material, thereby effectively fixing the solid lubricating material. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the structural diagram of the suction anchor body;

[0015] Figure 2 This is a schematic diagram for installing the mesh cloth;

[0016] Figure 3 It is a schematic diagram for setting the thickness of solid lubricant material;

[0017] Figure numerals: 1. suction anchor top cover; 2. suction anchor body; 3. micro rivet; 4. solid lubricating material; 5. mesh cloth. DETAILED DESCRIPTION

[0018] The specific embodiments of the present invention are further described below with reference to the accompanying drawings.

[0019] The present invention provides a method for reducing drag during installation of a deep-sea suction anchor, wherein micro rivets (2) are arranged at intervals on a suction anchor body (1) to achieve the arrangement of a mesh cloth (3), and then a solid lubricating material (4) is adhered to the anchor body. The thickness of the solid lubricating material is the largest at the bottom of the suction anchor and does not exceed 50% of the wall thickness of the suction anchor to avoid affecting the initial burial depth; and the thickness is the smallest at the top and is not less than 5% of the wall thickness of the suction anchor body to avoid premature wear and failure to achieve lubrication.

[0020] A method for reducing drag during installation of a deep-sea suction anchor, the construction method of which is as follows: micro rivets (2) are welded in a ring along the suction anchor body (1), the spacing between each ring of micro rivets (2) not exceeding 1 times the diameter of the suction anchor, and then a mesh cloth (3) is connected to the micro rivets (2) to cover the side wall of the suction anchor body (1). The anchor is hoisted in a lubrication workshop and solid lubricating material (4) is glued. The glued thickness of the bottom area of ​​the suction anchor body (1) decreases linearly along the height direction of the anchor body, the bottom solid lubricating thickness is not less than 50% of the suction anchor wall thickness, and the top thickness is not less than 5%. During the suction anchor installation process, as the suction anchor installation depth increases, the solid lubricating material thickness gradually wears away under the interaction between the anchor wall and the soil, and the wear degree of the solid lubricating material thickness near the bottom is the greatest. When the anchor is installed to the designated position, the lubricating material thickness gradually wears away and decreases to the minimum, but at this time there is still an effective lubricating effect. Based on the above operations, the installation drag reduction method suitable for deep-sea suction anchors can achieve the reduction of side wall friction resistance throughout the entire process of suction anchor installation.

[0021] The above embodiments further illustrate the purpose, technical solutions and advantages of the present invention in detail. It should be understood that the above is only an embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for reducing drag during installation of a deep-sea suction anchor, characterized in that: The invention comprises two parts: pre-treatment of deep-sea suction anchor installation and post-treatment of solid lubricating material adhesion. The pre-treatment of deep-sea suction anchor installation comprises: pre-arranging micro-rivets with annular spacing on the inner and outer side walls of the deep-sea suction anchor, and then fixing mesh cloth on the micro-rivets. The post-treatment of solid lubricating material adhesion comprises: adhering solid lubricating material on the mesh cloth, and the lubricating material adhesion has different thicknesses within the height range of the anchor body.

2. The method for reducing drag during installation of a deep-sea suction anchor according to claim 1 is characterized by: The micro rivets are arranged in a ring shape and are evenly distributed on the inner and outer side walls of the suction anchor. The interval between the micro rivets in each ring is equal to the diameter of the suction anchor.

3. The method for reducing drag during installation of a deep-sea suction anchor according to claim 1 is characterized by: The mesh cloth is made of materials such as polyester, polypropylene, and glass fiber, and a certain gap is left between the mesh cloth and the side wall of the suction anchor.

4. The method for reducing drag during installation of a deep-sea suction anchor according to claim 1 is characterized by: In the post-adhesion treatment of the solid lubricating material, the solid lubricating material can be selected in the form of a graphite / metal composite coating and a ceramic-based self-lubricating material, and a suitable plasticized adhesive is selected for temporary shaping.

5. The method for reducing drag during installation of a deep-sea suction anchor according to claim 1 is characterized by: The sticking thickness of the solid lubricating material decreases linearly along the height direction of the suction anchor, the maximum sticking thickness does not exceed 50% of the side wall thickness of the suction anchor, and the minimum sticking thickness is 5% of the side wall thickness of the suction anchor.

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