Vibration sinking installation method for underwater steel cylinder with uneven soil distribution

Abstract

The invention relates to a vibration sinking installation method for a steel cylinder, in particular to a vibration sinking installation method for an underwater steel cylinder with uneven soil distribution, which comprises the following specific installation steps: 1, a crane ship is fixedly connected with a vibratory hammer group through a hoisting lock, the vibratory hammer group is hoisted to be right above the steel cylinder, the steel cylinder is clamped through a hydraulic clamping jaw, and the vibratory hammer group is hoisted to be right above the steel cylinder; hoisting the steel cylinder to a preset position on the water surface; secondly, the steel cylinder slowly descends until the steel cylinder and the vibratory hammer set are all submerged below the water surface; thirdly, the steel cylinder is lowered step by step to make contact with the seabed surface, the E-shaped hook head is deloaded step by step and slowly falls, the steel cylinder enters mud by means of self weight, and the perpendicularity of the steel cylinder is adjusted after the steel cylinder is stabilized; fourthly, the vibratory hammer set is started, the steel cylinder is vibrated into mud, and the perpendicularity of the steel cylinder is adjusted again after the steel cylinder is stabilized; and fifthly, the operation in the fourth step is repeated, the steel cylinder descends to the designated mud entering depth, the hydraulic clamping jaw is loosened, and the vibratory hammer set is lifted and placed on the deck of the transportation barge.

Description

Technical Field

[0001] This invention relates to a method for vibratory sinking of steel cylinders, and more particularly to a method for vibratory sinking of steel cylinders underwater in areas with uneven soil distribution. Background Technology

[0002] With the continuous development of oil and gas exploration and development in the Bohai Sea, the proven reserves of oil and gas in restricted areas are constantly increasing, and it is poised to become a key area for increasing oil and gas reserves and production in my country. In areas with restricted navigation, subsea oil and gas production systems are mainly used for development. These systems need to be buried below the seabed, and their outer protective structure is primarily a large-diameter steel cylinder structure. Conventional steel cylinder structures have a smaller diameter and are mainly used for foundation reinforcement in bridge construction and artificial island construction, remaining above the water surface after installation. However, the installation of subsea steel cylinders requires installation below the seabed, and there is no precedent for such installation. During the installation of conventional steel cylinders, verticality control is relatively simple due to their small diameter and large height. However, the larger diameter and smaller height of the subsea steel cylinder, coupled with the uneven soil distribution in the installation area, makes verticality control extremely difficult.

[0003] Chinese Patent CN114855796B discloses a multi-vessel coordinated method for vibratory sinking of steel cylinders at sea. This method utilizes three main working vessels—a large floating crane, an offshore support auxiliary vessel, and a transport barge—to complete the traditional vibratory sinking operation of steel cylinders. The offshore support auxiliary vessel completes the land-based connection and commissioning of the multi-hammer linkage system, while the large floating crane completes the offshore vibratory sinking process. This invention can significantly shorten the deployment time of the large floating crane and greatly save on project investment costs. It is a convenient and advantageous multi-hammer linkage system vibratory sinking operation method with broad application prospects and can significantly reduce project investment costs.

[0004] However, during underwater vibratory sinking of steel cylinders, the uneven distribution of seabed soil in the construction area and the large differences in the mechanical properties of different soils lead to uneven resistance on the steel cylinders, resulting in difficulties in attitude control, easy tilting and deviation, and high resistance and difficulty in penetrating hard soil layers. Summary of the Invention

[0005] The main objective of this invention is to provide a method for vibratory sinking of underwater steel cylinders in areas with uneven soil distribution. This method addresses the problems mentioned in related technologies, such as uneven distribution of seabed soil in the construction area, significant differences in the mechanical properties of different soil types, uneven resistance to the steel cylinder during underwater vibratory sinking, resulting in difficulties in attitude control, easy tilting and deviation, and high resistance and difficulty in penetrating hard soil layers.

[0006] To achieve the above objectives, according to one aspect of the present invention, a method for vibratory sinking of an underwater steel cylinder in unevenly distributed soil is provided, the specific installation steps of which are as follows: The first step is to connect the crane vessel to the vibratory hammer assembly via a lifting lock, lift the vibratory hammer assembly to the top of the steel cylinder, and then use hydraulic grippers to hold the steel cylinder and lift it to a preset position on the water surface. The second step is to slowly lower the steel cylinder until the steel cylinder and the vibratory hammer assembly are completely submerged below the water surface. The third step is to lower the steel cylinder step by step to contact the seabed surface, and gradually reduce the load of the hook head and slowly lower it. The steel cylinder sinks into the mud by its own weight. After stabilization, the verticality of the steel cylinder is adjusted. The fourth step is to start the vibratory hammer assembly, and the steel cylinder is vibrated and sunk into the mud. After stabilization, the verticality of the steel cylinder is readjusted. Fifth, repeat the operation of the fourth step, lower the steel cylinder to the designated mud depth, release the hydraulic clamps, lift the vibratory hammer assembly and place it on the deck of the transport barge.

[0007] Furthermore, in the first step, the lifting lock includes at least a mountain-shaped hook head fixedly connected to the crane vessel, the vibratory hammer assembly fixedly connected below the mountain-shaped hook head, and the hydraulic gripper fixedly connected to the bottom of the vibratory hammer assembly.

[0008] Furthermore, in the first step, before installing the steel cylinder, a foundation trench is dug on the pre-set seabed surface, and the foundation trench is square.

[0009] Furthermore, in the second step, a small platform is fixedly installed on the steel cylinder for placing an attitude monitoring instrument, which is used to detect the attitude of the steel cylinder.

[0010] Furthermore, in the third step, the verticality of the steel cylinder after each stage of self-sinking is less than or equal to 0.5°.

[0011] Furthermore, in the third step, when the steel cylinder tilts at an angle greater than 0.5° during the self-sinking process, the hook is immediately stopped.

[0012] Furthermore, in the fourth step, the vibration method of the steel cylinder is point vibration.

[0013] Furthermore, in the fourth step, the verticality of the steel cylinder is adjusted by a correction device.

[0014] Furthermore, in the fourth step, the correction device includes several anchor cables fixedly installed around the perimeter of the crane vessel. The anchor cables are used to adjust the position of the crane vessel laterally and to adjust the verticality of the steel cylinder by controlling the height of the hook on one side of the mountain-shaped hook.

[0015] Furthermore, in the fourth step, a cross steel cable is fixedly connected to the side wall of the steel cylinder, and a bow winch is fixedly connected to one end of the cross steel cable. The cross steel cable is used to control the azimuth angle of the steel cylinder.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. In this method of vibratory sinking installation of underwater steel cylinders with uneven soil distribution, a large-diameter steel cylinder can be driven underwater to the muddy surface of the seabed, which solves the problems of uneven soil distribution and difficulty in continuous vibratory sinking construction, and improves the overall strength and durability of the underwater structure.

[0017] 2. In this method of vibratory sinking installation of underwater steel cylinders with uneven soil distribution, short-time point vibration and correction measures are combined to effectively solve the problem of verticality control of large-diameter underwater steel cylinders. This allows construction personnel to more easily control the attitude of the steel cylinders, reduces the number of rework and adjustments caused by verticality issues, lowers the technical difficulty and operational requirements of construction, meets the needs of underwater oil and gas production system installation in navigation-restricted areas, and is simple and convenient to operate, reducing construction costs and safety risks.

[0018] 3. In this underwater vibratory sinking installation method for steel cylinders in uneven soil distribution, an attitude monitoring device is installed. Under conditions of uneven soil distribution, the attitude device can quickly report changes in the attitude of the steel cylinder caused by different soil resistances, enabling construction personnel to make rapid adjustments to adapt to the installation requirements under complex geological conditions. Furthermore, by controlling the height of one side of the mountain-shaped hook, the verticality of the steel cylinder can be precisely adjusted, ensuring that the steel cylinder remains vertical throughout the vibratory sinking process, meeting design requirements. By deploying and retracting cross steel cables, the azimuth angle of the steel cylinder can be flexibly adjusted, effectively addressing azimuth deviations caused by uneven soil distribution, ensuring accurate positioning of the steel cylinder, and improving installation quality. Attached Figure Description

[0019] Figure 1 This is a diagram of the steel cylinder vibratory sinking installation structure in a preferred embodiment of the present invention; Figure 2 This is a plan view of the vibratory sinking installation of the steel cylinder in a preferred embodiment of the present invention; Figure 3 This is a schematic diagram of the vibratory sinking installation process of the steel cylinder in a preferred embodiment of the present invention.

[0020] Figure label: 1. Crane vessel; 2. Transport barge; 3. Steel cylinder; 4. Vibratory hammer assembly; 5. Hydraulic gripper; 6. Mountain-shaped hook; 7. Foundation trench; 8. Anchor cable; 9. Cross steel cable. Detailed Implementation

[0021] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0022] This embodiment provides a method for vibratory sinking of an underwater steel cylinder in areas with uneven soil distribution. The specific installation steps are as follows: The first step involves transporting the steel cylinder 3 and the vibratory hammer assembly 4 to the construction site via transport barge 2. The crane vessel 1 is then fixedly connected to the vibratory hammer assembly 4 using lifting locks. The vibratory hammer assembly 4 is lifted to a position directly above the steel cylinder 3 and then lowered to the top of the steel cylinder 3. The steel cylinder 3 is then clamped by hydraulic grippers 5, a device with strong clamping force. Powered by a hydraulic system, the hydraulic grippers 5 tightly clamp the steel cylinder 3. The operator tightens the hydraulic grippers 5 to ensure that the steel cylinder 3 is firmly clamped, preventing safety hazards such as slippage during subsequent lifting. The steel cylinder 3 is then loaded onto the transport barge 2 and secured. Finally, the steel cylinder 3 is lifted to a predetermined position on the water surface. The second step is to slowly lower the steel cylinder 3 until both the steel cylinder 3 and the vibratory hammer assembly 4 are completely submerged below the water surface. The descent is stopped when the bottom of the steel cylinder 3 is 0.4 to 0.6 meters from the seabed. This distance ensures that the steel cylinder 3 is close to the installation position and also provides sufficient space and time for subsequent attitude detection and adjustment. The third step involves lowering the steel cylinder 3 into contact with the seabed in stages, with the zigzag hook 6 gradually reducing its load and slowly lowering itself. The steel cylinder 3 sinks into the mud under its own weight. After each stabilization, the attitude of the steel cylinder 3 is adjusted to meet the requirements before proceeding to the next stage of lowering. The zigzag hook 6 is lowered in stages of 50t, slowly lowering itself. This staged load reduction is to ensure that the steel cylinder 3 can make stable and safe contact with the seabed and sink into the mud under its own weight. This staged load reduction method can avoid problems such as excessive speed of descent and loss of attitude control caused by releasing too much weight at once. After stabilization, the verticality of the steel cylinder 3 is adjusted. After each stage of self-sinking, the attitude data of the steel cylinder 3, including tilt angle and azimuth angle, needs to be acquired in real time through attitude monitoring instruments. Based on this data, it is determined whether the attitude of the steel cylinder 3 meets the installation requirements. The fourth step is to start the vibratory hammer group 4 after the steel cylinder 3 sinks into the mud. This generates strong vibration energy, which is transmitted to the steel cylinder 3 through the hydraulic gripper 5. The steel cylinder 3 sinks into the mud. This method of sinking can effectively overcome the resistance of the seabed soil and allow the steel cylinder 3 to reach the designed depth of mud penetration. After stabilization, the verticality of the steel cylinder 3 is adjusted again. Fifth, repeat the operation of the fourth step. The height of the steel cylinder 3 gradually decreases until it reaches the designated mud depth. At this point, release the hydraulic gripper 5, lift the vibratory hammer assembly 4 until it leaves the water surface, and place it on the deck of the transport barge 2. Then, release the connection lock to complete the equipment recovery.

[0023] like Figure 1As shown, in the first step, the lifting lock includes at least a mountain-shaped hook head 6 fixedly connected to the crane vessel 1. The mountain-shaped hook head 6 is an important lifting component with a unique structure and strong load-bearing capacity. The vibratory hammer assembly 4 is fixedly connected below the mountain-shaped hook head 6, and the hydraulic gripper 5 is fixedly connected to the bottom of the vibratory hammer assembly 4.

[0024] like Figure 1 As shown, in the first step, before installing the steel cylinder 3, a foundation trench 7 is dug on the pre-set seabed surface. The purpose of digging the foundation trench 7 is to provide a stable and suitable installation foundation for the steel cylinder 3, ensuring that the steel cylinder 3 can be firmly fixed on the seabed after installation. The foundation trench 7 is square and has a depth of 3 meters. This depth can meet the stability requirements of the installation of the steel cylinder 3, while taking into account construction costs and efficiency, and avoiding excessive digging that would waste resources.

[0025] like Figure 1 As shown, in the second step, a small platform is fixedly installed on the steel cylinder 3 for placing an attitude monitoring instrument. The attitude monitoring instrument is used to detect the attitude of the steel cylinder 3. After the steel cylinder 3 stops descending, the attitude monitoring instrument is immediately activated to conduct a comprehensive detection of the attitude of the steel cylinder 3. After confirming that the attitude of the steel cylinder 3 meets the installation requirements, the steel cylinder 3 continues to be lowered.

[0026] like Figure 1 and Figure 3 As shown, in the third step, the verticality of the steel cylinder 3 after each stage of self-sinking is less than or equal to 0.5°. Verticality is one of the important indicators for measuring the installation quality of the steel cylinder 3. If the verticality exceeds this range, it may cause problems such as uneven stress and poor stability of the steel cylinder 3 in subsequent use, affecting the safety and reliability of the entire project.

[0027] like Figure 1 and Figure 3 As shown, in the third step, when the steel cylinder 3 tilts at an angle greater than 0.5° during the self-sinking process, the hook is immediately stopped. This is because an excessively large tilt angle means that the posture of the steel cylinder 3 has deviated from the normal range. Continuing to lower it may cause the steel cylinder 3 to tilt more severely, or even fail to enter the mud smoothly, increasing the difficulty and risk of installation.

[0028] like Figure 1 As shown, in the fourth step, the steel cylinder 3 is vibrated in a point vibration manner. Point vibration means that the vibrating construction is carried out multiple times in a short period of time at a certain eccentric wheel speed. The interval time should not be too long. The duration of the first point vibration is 10 seconds. This can ensure the vibrating effect while avoiding excessive impact on the steel cylinder 3 and the surrounding seabed.

[0029] like Figure 1 and Figure 3As shown, during the vibratory settling process, the operator needs to gradually increase the vibration time based on the posture of the steel cylinder 3 after each settling. If the posture of the steel cylinder 3 is good after settling, and the verticality and azimuth angle meet the requirements, the vibration time can be appropriately increased to accelerate the settling speed. If the posture deviates, the posture needs to be adjusted first, and then the vibration time should be cautiously increased based on the effect of the adjustment to ensure that the settling process is safe, stable, and efficient.

[0030] like Figure 1 As shown, in the fourth step, the verticality of the steel cylinder 3 is adjusted by the correction device.

[0031] like Figure 2 and Figure 3 As shown, in the fourth step, the correction device includes several anchor cables 8 fixedly installed around the perimeter of the crane vessel 1. The anchor cables 8 are used to adjust the position of the crane vessel 1 laterally. Since the position of the crane vessel 1 may be affected by factors such as water flow and wind, it may shift, thereby affecting the verticality of the steel cylinder 3. By raising and lowering the anchor cables 8, the lateral position of the crane vessel 1 can be precisely adjusted to maintain it in a suitable posture, providing a basis for adjusting the verticality of the steel cylinder 3. Furthermore, the verticality of the steel cylinder 3 is adjusted by controlling the height of one side of the mountain-shaped hook head 6. That is, by controlling the lowering and raising of the height of one side of the mountain-shaped hook head 6, when one side of the hook head lowers, the tension on the steel cylinder 3 on that side decreases, and the steel cylinder 3 will tilt to that side; conversely, when one side of the hook head rises, the tension on the steel cylinder 3 on that side increases, and the steel cylinder 3 will tilt to the other side. Through this adjustment, the verticality of the steel cylinder 3 can be made to meet the requirements.

[0032] like Figure 2 As shown, in the fourth step, a cross steel cable 9 is fixedly connected to the side wall of the steel cylinder 3. One end of the cross steel cable 9 is fixedly connected to the bow winch. The cross steel cable 9 is used to control the azimuth angle of the steel cylinder 3. When it is necessary to adjust the azimuth angle of the steel cylinder 3, the operator starts the bow winch to perform the winding and unwinding operation of the cross steel cable 9. If the steel cylinder 3 deviates in a certain direction, the cross steel cable 9 in the other direction is tightened, while the cross steel cable 9 in the other direction is loosened, so that the steel cylinder 3 is subjected to a reverse tension, thereby gradually adjusting its azimuth angle until the azimuth angle required by the design is reached.

[0033] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for vibratory sinking of an underwater steel cylinder in unevenly distributed soil, characterized in that, The specific installation steps are as follows: First, the crane vessel (1) is fixedly connected to the vibratory hammer assembly (4) through the lifting lock, and the vibratory hammer assembly (4) is lifted to the top of the steel cylinder (3). The steel cylinder (3) is clamped by the hydraulic jaws (5) and lifted to the preset position on the water surface. The second step is to slowly lower the steel cylinder (3) until the steel cylinder (3) and the vibrating hammer assembly (4) are completely submerged below the water surface; The third step is to lower the steel cylinder (3) down to the seabed surface in stages, and gradually reduce the load of the mountain-shaped hook (6) and slowly lower it. The steel cylinder (3) enters the mud by its own weight. After stabilization, the verticality of the steel cylinder (3) is adjusted. Fourth step, start the vibratory hammer group (4), the steel cylinder (3) is vibrated and sunk into the mud, and after stabilization, the verticality of the steel cylinder (3) is adjusted again; Fifth step, repeat the operation of the fourth step, lower the steel cylinder (3) to the specified mud depth, release the hydraulic clamp (5), lift the vibratory hammer assembly (4) and place it on the deck of the transport barge (2).

2. The underwater steel cylinder vibratory sinking installation method for uneven soil distribution according to claim 1, characterized in that, In the first step, the lifting lock includes at least a mountain-shaped hook (6) fixedly connected to the crane vessel (1), the vibratory hammer assembly (4) fixedly connected below the mountain-shaped hook (6), and the hydraulic gripper (5) fixedly connected to the bottom of the vibratory hammer assembly (4).

3. The underwater steel cylinder vibratory sinking installation method for uneven soil distribution according to claim 1, characterized in that, In the first step, before installing the steel cylinder (3), a foundation trench (7) is dug on the preset seabed surface, and the foundation trench (7) is square.

4. The underwater steel cylinder vibratory sinking installation method for uneven soil distribution according to claim 1, characterized in that, In the second step, a small platform is fixedly installed on the steel cylinder (3) for placing an attitude monitoring instrument, which is used to detect the attitude of the steel cylinder (3).

5. The underwater steel cylinder vibratory sinking installation method for uneven soil distribution according to claim 1, characterized in that, In the third step, the verticality of the steel cylinder (3) after each stage of self-sinking is less than or equal to 0.5°.

6. The underwater steel cylinder vibratory sinking installation method for uneven soil distribution according to claim 1, characterized in that, In the third step, when the steel cylinder (3) tilts at an angle greater than 0.5° during the self-sinking process, the hook is immediately stopped.

7. The underwater steel cylinder vibratory sinking installation method for uneven soil distribution according to claim 1, characterized in that, In the fourth step, the vibration method of the steel cylinder (3) is point vibration.

8. The underwater steel cylinder vibratory sinking installation method for uneven soil distribution according to claim 1, characterized in that, In the fourth step, the verticality of the steel cylinder (3) is adjusted by the correction device.

9. The underwater steel cylinder vibratory sinking installation method for uneven soil distribution according to claim 8, characterized in that, In the fourth step, the correction device includes several anchor cables (8) fixedly installed at the four edges of the crane vessel (1). The anchor cables (8) are used to adjust the position of the crane vessel (1) laterally and to adjust the verticality of the steel cylinder (3) by controlling the height of the hook on one side of the mountain-shaped hook (6).

10. The underwater steel cylinder vibratory sinking installation method for uneven soil distribution according to claim 1, characterized in that, In the fourth step, a cross steel cable (9) is fixedly connected to the side wall of the steel cylinder (3), and a bow winch is fixedly connected to one end of the cross steel cable (9). The cross steel cable (9) is used to control the azimuth angle of the steel cylinder (3).

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