WO2020019560A1

WO2020019560A1 - Suction pile of buoyant tower platform

Info

Publication number: WO2020019560A1
Application number: PCT/CN2018/113315
Authority: WO
Inventors: 潘徐杰
Original assignee: 惠生（南通）重工有限公司
Priority date: 2018-07-25
Filing date: 2018-11-01
Publication date: 2020-01-30
Also published as: CN108945327A; CN108945327B

Abstract

A suction pile (1) of a buoyant tower platform. The suction pile (1) is a structure opened at the bottom and closed at the top. A pipe is provided on top of the suction pile (1). The suction pile (1) is shaped as a prism. The suction pile (1) of the buoyant tower platform greatly strengthens the overall torsion resistance of the buoyant tower platform compared with a cylindrical suction pile of an existing buoyant tower platform.

Description

Suction pile for buoyancy tower platform

Technical field

The invention relates to a suction pile or a suction anchor of a buoyancy tower platform, and belongs to the field of ocean engineering.

Background technique

The buoyancy tower platform is a platform that is also used to collect and store condensate or crude oil. The shape of the buoyancy tower platform is similar to the SPAR platform, but the difference is that the buoyancy tower platform cabin structure extends all the way to the sea floor and passes its own shallow The base cylindrical suction pile fixes it on the sea floor and moves with the waves. This shallow foundation suction pile acts as a hinge. The suction pile shakes with the platform in the waves. Given that the main body of the suction pile is inserted into the soil, The swing of the platform and suction pile is random, so the cylindrical suction pile can minimize the resistance generated when it shakes in all directions.

The platforms disclosed in the prior art patent numbers 2011800612002 and 2013104737690 are representative technologies. In view of the fact that the buoyancy tower in the prior art can only arrange one suction pile, it cannot form a torsional bending moment, and the traditional cylindrical suction pile has extremely high torsion resistance. Weak, the platform is susceptible to overall rotation during wind and waves, and the platform can only be pulled by auxiliary means to prevent the platform from rotating.

Summary of the Invention

The technical problem to be solved by the present invention is to overcome the shortcoming of the weak torsion resistance of the buoyancy tower platform, and provide a polygonal prismatic suction pile suitable for the buoyancy tower and capable of enhancing the torsion resistance to enhance the overall torsion resistance of the buoyancy tower.

In order to solve the above technical problems, the suction pile of the buoyancy tower platform of the present invention is a closed structure with an open bottom and a closed structure. A pipeline is provided on the top of the suction pile, and the suction pile is prismatic.

In a further optimization scheme of the foregoing technical solution, the suction pile is an equilateral polyhedral prism, and the prism surface of the equilateral polyhedral prism is 8 to 24.

The above technical solution is further optimized. The prismatic surface of the suction pile is adjusted according to the softness of the subsea soil. When the soil body is clay and away from the liquid limit, a prismatic suction pile composed of 19 to 24 equilateral surfaces is selected. ; When the soil body is clay or sand and near the liquid limit, select a prismatic suction pile consisting of 12 to 18 equilateral faces; when the soil body is fine sand, choose 8 to 11 equilateral faces Prismatic suction pile.

In a further optimization scheme of the foregoing technical solution, when there are 8 to 11 prism surfaces, a protruding member is longitudinally provided on an outer side wall of the suction pile, and the protruding member is disposed at a connection between adjacent prism surfaces.

In a further optimization solution of the foregoing technical solution, the protruding member is an acute-angled triangular prism member.

Compared with the cylindrical suction pile of the existing buoyancy tower platform, the suction pile of the buoyancy tower platform of the present invention greatly enhances the overall torsion resistance of the buoyancy tower.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a structural diagram of a platform using a traditional cylindrical suction pile;

FIG. 2 is a structural diagram of a prismatic suction pile composed of 8 equal sides;

FIG. 3 is a structural diagram of a platform using an 8-sided surface to form a prismatic suction pile and a surface protruding member;

Figure 4 is a cross-section comparison of an equilateral prismatic suction pile and a cylindrical suction pile using 8 to 24 faces.

detailed description

The embodiments of the present invention are described below with reference to FIGS. 1 to 4.

The suction pile 1 is a support of the buoyancy tower platform at the bottom of the sea floor, and it plays the role of articulation connecting the platform and the sea floor.

The polygonal prismatic suction pile 1 according to the present invention is a conventional cylindrical suction pile 1 replaced by a polygonal prismatic suction pile 1 to enhance the overall torsion resistance of the platform in the wind and waves. The prismatic suction pile 1 and the platform The connection mode is consistent with the traditional cylindrical suction pile 1.

The lower surface of the prismatic suction pile 1 is open and the top is closed, and a ventilation / water outlet is left on the top to extend above the sea level, which is convenient for the platform to install the prismatic suction pile to discharge water and gas.

The prismatic suction pile 1 uses a prism composed of an equilateral surface to maintain the symmetry of the suction pile, so that the swing damping of the suction pile in the soil in any horizontal direction is basically balanced.

There are upper and lower limits for the number of faces that make up a prismatic suction pile, and if too few faces are used to form a prism, the distribution of the vibration damping of the suction pile on the horizontal plane will be seriously uneven, so it is recommended that no less than 8 equilateral faces make up the prism However, if too many equilateral surfaces are used to form the prism, the prism can be approximated as a cylinder, and its torsional bending moment will quickly disappear. Therefore, the number of equilateral surfaces that make up the prism cannot be more than 24. The cross section can be seen in Figure 4, which is the octagonal suction pile cross section 8, the nine-sided suction pile cross section 9, the decagonal suction pile cross section 10, the eleven-sided suction pile cross section 11, and the twelve sides. Shaped suction pile cross section 12, 13-sided suction pile cross section 13, 14-sided suction pile cross section 14, 15-sided suction pile cross-section 15, 16-sided suction pile cross-section 16, 17-sided suction force Cross-section of pile 17, Cross-section of octagonal suction pile 18, Cross-section of nineteen-sided suction pile 19, Cross-section of twenty-sided suction pile 20, Cross-section of twenty-sided suction pile 21, Twenty-two sides Cross-section of 22-shaped suction pile Surface 23, twenty quadrangular cross section suction pile 24, a circular cross-section suction pile 3.

When the main soil body is clay, away from the liquid limit, and the undrained shear strength is large, a prismatic suction pile composed of 19 to 24 equilateral sides is used.

When the main soil body is clay or sand, near the liquid limit, and the undrained shear strength is low, use prismatic suction piles consisting of 12 to 18 equilateral faces.

In liquefied fine sand, or clay with extremely low liquefaction undrained shear strength, fewer isoplanar prisms are required to maximize the torsional capacity, such as a prism composed of 8 to 11 isolateral surfaces Type suction pile.

In some soils, if using a suction pile composed of 8 equilateral faces is not enough to prevent the platform from twisting, a protruding member 2 can be added at the corner end of the prism to increase the damping. For details, refer to FIG. 3.

The design principle of the present invention: The prismatic suction pile 1 can obviously increase the torsional bending moment in water, and as the number of prismatic surfaces decreases, the increased torsional bending moment will increase. Given that the direction of the waves is random and the direction of the buoyancy tower and the suction pile 1 is also random, in order to keep the platform's shaking damping approximation in all directions, the suction pile 1 needs to use an equilateral polyhedron prism, and if too few The formation of equilateral polyhedral prisms from the surface will cause the uneven distribution of the suction damping of the suction pile 1 on the horizontal plane, which will affect the performance of the platform. Therefore, it is recommended that there be no less than 8 equilateral surfaces forming the prism. If too many equilateral surfaces are used to form the prism, the prism can be approximated as a cylinder, and its torsional bending moment will quickly disappear. Therefore, it is recommended that no more than 24 equilateral surfaces be included in the prism. The specific number of faces of the prismatic suction pile is used according to the static sounding of rock and soil in the sea area where the platform is installed and the results of various tests of soil sampling, especially depending on the undrained shear strength of the soil and the fluidity of the soil. Plasticity index. When the soil body is clay, away from the liquid limit, and the undrained shear strength is large, use a prismatic suction pile composed of 19 to 24 equilateral faces because the soil is compact and more equilateral faces are used. Several prismatic suction piles can provide sufficient torsional moment without increasing excessive suction pile vibration damping. In compact soil, too high shaking damping can easily cause structural damage to the suction pile; When the soil body is clay or sand, near the liquid limit, and the undrained shear strength is low, use prismatic suction piles consisting of 12 to 18 equilateral faces. The soil should be soft and more used. The torsional moment provided by the prismatic suction pile composed of equilateral faces is not enough. It is necessary to reduce the number of faces to increase the torsional moment. In soft soil, slightly increasing the shaking damping will not cause the structural damage of the suction pile. Easily liquefied fine sand, or clay with extremely low liquefaction undrained shear strength, requires fewer isoplanar prisms to maximize the torsional capacity, ie, composed of 8 to 11 isolateral surfaces Column-type suction pile, in this kind of soil, excessive shaking damping will not cause structural damage to the suction pile 1, and in this case, a protruding member 2 may be added on the surface of the suction pile to increase the torsion resistance Moment.

Claims

The suction pile of the buoyancy tower platform is a closed structure with an open bottom and a closed structure. A pipeline is provided on the top of the suction pile, and the suction pile is prismatic.
The suction pile of the buoyancy tower platform according to claim 1, wherein the suction pile is an equilateral polyhedron prism, and the number of prism surfaces of the equilateral polyhedron prism is 8 to 24.
The suction pile of a buoyancy tower platform according to claim 2, characterized in that the prismatic surface of the suction pile is adjusted according to the softness of the subsea soil. When the soil body is clay and is far from the liquid limit, select 19 to 24. A prismatic suction pile consisting of two equilateral faces; when the soil body is clay or sandy soil and near the liquid limit, select a prismatic suction pile consisting of 12 to 18 equilateral faces; when the soil body is silt fine sand, Choose a prismatic suction pile consisting of 8 to 11 equilateral faces.
The suction pile of a buoyancy tower platform according to claim 3, wherein when the prism surface is 8 to 11, a protruding member is longitudinally provided on an outer side wall of the suction pile, and the protruding member is disposed adjacent to The connection between prism faces.
The suction pile of a buoyancy tower platform according to claim 4, wherein the protruding member is an acute-angled triangular prism member.