CN111055969A

CN111055969A - Power injection anchor with punching semicircular anchor wing and capable of enhancing in-place bearing capacity

Info

Publication number: CN111055969A
Application number: CN201911231512.8A
Authority: CN
Inventors: 闫玥; 姚烨; 付登锋; 周泽峰
Original assignee: Frontier Technology Research Institute of Tianjin University Co Ltd
Current assignee: Frontier Technology Research Institute of Tianjin University Co Ltd
Priority date: 2019-12-05
Filing date: 2019-12-05
Publication date: 2020-04-24

Abstract

The invention discloses a perforated semicircular anchor wing power penetration anchor capable of enhancing in-place bearing capacity. The invention designs the water permeable holes, and effectively improves the drainage condition of the semicircular anchor wing power penetration anchor. During the injection process of the injection anchor, the sinking water resistance cannot be increased, and the construction cost cannot be increased compared with the traditional power injection anchor; the existence of the water-permeable holes enables the positive and negative pore pressures on the two sides of the anchor body to be constantly balanced, and meanwhile, the increase of the drainage paths enables the generated pore water pressure to be constantly dissipated, so that the weakened soil body strength is quickly recovered due to disturbance, and the pulling resistance of the anchor is greatly improved. Meanwhile, the invention also has the advantages of simple structure, convenient installation and high reutilization.

Description

Power injection anchor with punching semicircular anchor wing and capable of enhancing in-place bearing capacity

Technical Field

The invention belongs to the technical field of marine geotechnical engineering design and construction, relates to a semicircular anchor wing dynamic penetration anchor of a mooring system of a deep sea structure, and particularly relates to a dynamic penetration anchor capable of enhancing in-situ bearing capacity.

Background

In recent years, with the continuous development of oil and gas resources in shallow sea of China, the oil reserves are reduced day by day, and the development of offshore oil exploitation areas to deep sea areas is a necessary trend. This puts higher demands on the mooring system in the form of a conventional offshore platform structure. The current internationally accepted deepwater mooring system mainly comprises fixed anchor buttock drag anchors, normal bearing anchors, suction penetration flat plate anchors, power penetration anchors and other structural forms. The technique related to the present invention is dynamic penetration of semicircular plate anchors.

The existing dynamic penetration semicircular plate anchor is a novel deep sea anchoring foundation appearing in recent years, and during construction, the plate anchor is firstly released from a certain height away from a seabed to enable the plate anchor to sink in an accelerating way under the action of dead weight, a certain impact energy is obtained when the plate anchor reaches the surface of a seabed soil body, penetration on the seabed is completed under the action of kinetic energy, then a weight rod is pulled out through a recovery chain, the plate anchor moves (rotates and pulls upwards) under the dragging of an anchor chain, and the plate anchor reaches a final bearing capacity state until the plate anchor is approximately vertical to the loading direction of the anchor chain, so that the installation of the penetration semicircular plate anchor is completed. The plate anchor obtains the maximum in-place bearing capacity at this time. The power penetration semicircular plate anchor has the advantages of convenience in operation, low cost and accuracy in positioning. But has the following defects: during the process of penetration and rotation of the penetration anchor, great disturbance is generated on the surrounding soil body, a large amount of positive excess pore water pressure is generated on the pressed side soil body of the plate anchor, negative excess pore water pressure is generated on the pulled side soil body, and the excess pore water pressure is generated and gathered, so that the effective stress of the surrounding soil body is greatly reduced, and the anti-pulling capacity of the anchor is greatly reduced. There is a research surface that the non-drainage shear strength of the soil body is rapidly reduced during the penetration process and the rotation process, so that the anti-pulling capacity of the anchor is 33% lower than the designed value, which is extremely dangerous in the engineering.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a novel semicircular anchor wing power penetration anchor capable of accelerating the consolidation of a soil body, so that the soil body disturbed by the penetration semicircular anchor is quickly consolidated under the condition of increasing drainage paths, the original strength is recovered at a higher speed, the in-situ bearing performance of the penetration anchor is improved, the uncertainty of penetration depth is reduced, the installation is simple and convenient, and the repeated utilization rate is high.

The technical scheme of the invention is as follows:

a power injection anchor with a perforated semicircular anchor wing and capable of enhancing in-situ bearing capacity comprises a semicircular anchor wing and a counterweight probe rod, wherein a counterweight rod cap used for probing into a counterweight rod sling chain is arranged at the top of the counterweight probe rod; the semicircular anchor wings are fixed on the plate anchor connecting sleeve, and the counterweight probe rod is arranged in the plate anchor connecting sleeve; the edge of the semicircular anchor wing is provided with an anchor eye which connects the mooring rope with the semicircular anchor wing; a group of water permeable holes are uniformly arranged on the semicircular anchor wings.

Preferably, the number of the semicircular anchor wings is four, the semicircular anchor wings are uniformly arranged on the periphery of the plate anchor connecting sleeve, and the edges of the semicircular anchor wings are provided with anchor eyes.

Preferably, the counterweight probe is 10m in length and 1.2m in diameter.

Preferably, the plate anchor connecting sleeve has an inner diameter of 1.56m and a length of 3.2 m.

Preferably, the diameter of the semicircular anchor wing is 3.2m, the distance from the anchor eye on the anchor wing to the axis of the penetrating anchor is 1.516m, and the thickness of the anchor wing is 0.18 m.

Furthermore, the shape and the interval arrangement of the water permeable holes can be adjusted according to the structural strength and the consolidation characteristics, and can adopt a round shape, a square shape, a triangular shape and a strip shape, wherein the strip shape can be a regular rectangular strip shape, and can also be an arc shape and a curve arc strip shape.

Furthermore, after the water permeable holes are punched, the water permeable holes need to be filled with a drainage material with proper structural strength.

Further, the recommended value of the perforation rate of the water permeable holes cannot exceed 15%, and the perforation rate is the ratio of the area of the open holes to the total area (the total area is the total area of the anchor wings where the perforation positions are located).

Further, the punching position of the permeable hole is mainly arranged on the anchor wing, but if the structure of the balance weight probe rod allows, punching can also be arranged, for example, if dense sand is used for filling the anchor rod instead of concrete, the balance weight probe rod can be punched, and the hole is sealed by a drainage material, so that better in-place drainage performance is achieved, and in-place bearing capacity is improved.

The invention has the advantages and positive effects that: the plane of the permeable hole is vertical to the penetration surface of the dynamic penetration anchor, so that the sinking water resistance cannot be generated to influence the penetration speed; meanwhile, energy loss is not increased, and compared with the traditional power penetration anchor, the construction cost is not increased; the existence of the water permeable holes enables the positive pore pressure and the negative pore pressure on the two sides of the anchor body to be constantly balanced, so that the effective stress is in a stable state, and meanwhile, the generated pore water pressure is rapidly dissipated due to the increase of drainage paths, so that the intensity of a soil body weakened by disturbance is rapidly recovered. Therefore, the pulling resistance of the anchor can be greatly improved, and the anchor has strong practical value in actual engineering, thereby having better development prospect.

Drawings

FIG. 1 is a top elevational view of the exterior of the structure of the present invention;

FIG. 2 is a side elevational view of the structure of the present invention;

in the figure: 1. the balance weight rod comprises a balance weight rod cap 2, an anchor eye 3, a water permeable hole 4, a semicircular anchor wing 5, a plate anchor connecting sleeve 6 and a balance weight probe rod.

Detailed Description

For further understanding of the contents, features and effects of the present invention, the following embodiments are exemplified and will be described in detail with reference to the accompanying drawings:

referring to fig. 1 to 2, a semicircular power penetration anchor with anchor wings capable of enhancing in-place bearing capacity includes a counterweight probe 6 and a counterweight cap 1 disposed at a top end portion for probing a counterweight chain; the semi-circular anchor wing 4 is arranged at the tail part, the semi-circular anchor wing is fixed on the plate anchor connecting sleeve 5, and the counterweight probe rod is arranged in the plate anchor connecting sleeve; the semicircular plate anchor 4 and the plate anchor connecting sleeve 5 are fixed by welding; the edge of the semicircular anchor wing is provided with an anchor eye 2 which connects the mooring rope with the semicircular anchor wing; a group of water permeable holes 3 (in this case, circular holes) are uniformly arranged on the semicircular anchor wings 4.

The practical operation construction method of the embodiment is as follows:

(1) a weighted probe 6 is passed through the plate anchor connecting sleeve 5.

(2) The counterweight rod cap 1 is connected with a counterweight rod sling chain, and the anchor eye 2 is connected with an anchor chain.

(3) The whole power penetration anchor is vertically and slowly put into water and released at a position 50-100m away from the underwater soil surface, so that the anchor falls freely and penetrates into the seabed.

(4) When the semicircular power penetration anchor finishes penetration in the seabed under the action of self weight and is stable in soil, the counterweight probe rod 6 is recovered through the counterweight rod hanging chain.

(5) After a period of time, the semicircular anchor wings 4 are pulled up by the anchor chain in a rotating manner until the anchor wings 4 reach the final bearing capacity state. And finishing the installation of the power anchor.

Although the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments, which are merely illustrative and not restrictive, and those skilled in the art can make many modifications without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. The utility model provides a can strengthen semi-circular anchor wing power of punching that bearing capacity is in place penetrates anchor which characterized in that, includes semi-circular anchor wing and counter weight probe rod, semi-circular anchor wing fix on board anchor hookup sleeve, in the counter weight probe rod was put into board anchor hookup sleeve, the top of counter weight probe rod sets up the counter weight rod cap that is used for exploring the counter weight rod chain sling, has arranged a set of hole of permeating water on the semi-circular anchor wing for effectively improve the drainage condition of semi-circular anchor wing power penetration anchor.

2. The perforated semicircular anchor wing power penetration anchor capable of enhancing in-place bearing capacity according to claim 1, wherein the number of the semicircular anchor wings is four, and the semicircular anchor wings are uniformly arranged on the periphery of the plate anchor coupling sleeve, and the edge of one semicircular anchor wing is provided with an anchor eye.

3. The semi-circular anchor wing power penetration anchor of claim 1, wherein said plate anchor coupling sleeve has an inner diameter of 1.56m and a length of 3.2 m.

4. The semi-circular anchor wing power penetration anchor of claim 1, wherein said weighted probe is 10m long and 1.2m in diameter.

5. The dynamic penetration anchor with perforated semicircular anchor wings capable of enhancing in-place bearing capacity according to claim 1, wherein the semicircular anchor wings have a diameter of 3.2m, the distance from the anchor eye on the anchor wing to the axial center of the penetration anchor is 1.516m, and the thickness of the anchor wings is 0.18 m.

6. The power penetration anchor with perforated semicircular anchor wings capable of enhancing in-place bearing capacity as claimed in claim 1, wherein the shape and the interval arrangement of the water permeable holes are adjusted according to the structural strength and the consolidation characteristics, the shape of the water permeable holes is selected from the group consisting of circular, square, triangular and strip-shaped, and the strip-shaped may be a regular rectangular strip or an arc or a curved arc strip.