Grouting connecting section based on negative poisson's ratio pipe structure and application thereof

Abstract

The application discloses a grouting connecting section based on a negative Poisson's ratio pipe structure and application thereof, and the connecting section comprises an outer sleeve pipe, an inner pile pipe and high-strength grouting material filled in the annular cavities of the two pipes, wherein the outer sleeve pipe is a structural negative Poisson's ratio steel pipe, the pipe wall of which is composed of a steel plate with a periodic negative Poisson's ratio cell structure, the inner pile pipe is a conventional steel pipe, and the wall surfaces of the outer sleeve pipe and the inner pile pipe towards the grouting material are provided with shear keys; the negative Poisson's ratio cell structure generates transverse shrinkage deformation when subjected to axial compression, so that the outer sleeve pipe forms active enhancement of the annular constraint on the high-strength grouting material. The application can continuously maintain or even enhance the annular extrusion of the grouting material under the action of the axial pressure as the main load, improve the interface normal pressure and the frictional force transmission state, inhibit the cracking of the grouting material, the interface debonding and sliding and the crushing of the oblique pressure short column near the shear keys, and thus the bearing capacity, ductility, energy dissipation capacity and fatigue life of the grouting connecting section are improved.

Description

Technical Field

[0001] This invention relates to the field of offshore jacket foundation technology, and in particular to a grouting connection section based on a negative Poisson's ratio pipe structure and its application. Background Technology

[0002] Offshore jacket structure foundations operate in complex environments subjected to wind, waves, currents, ice loads, and vibrations from turbine operation. The foundation connections must simultaneously meet requirements for high load-bearing capacity, good fatigue performance, and long-term durability. Grouted connection sections are commonly used between the jacket legs and the steel pipe piles, and between the skirt piles and the sleeve. This involves filling the annular space between the outer sleeve and the inner pile pipe with high-strength grout, and transferring loads through shear keys, interfacial friction, and the pressure exerted on the grout.

[0003] For grouted joints with shear keys, axial loads and bending moments are typically transferred through local compression zones near the shear keys and diagonally compressed short columns between adjacent shear keys. The compressive strength, peak compressive strain, residual bearing capacity after cracking, and lateral restraint of the grout by the steel pipe directly affect the ultimate bearing capacity and fatigue life of the joint. When the joint is subjected to large axial compressive loads, ordinary structural steel pipes may enter a yielding or local buckling state earlier. Their circumferential restraint capacity decreases with deformation due to the positive Poisson's ratio effect (lateral contraction when stretched and lateral expansion when compressed). At the same time, the grout also tends to expand laterally. Under the combined effect of these two factors, the restraint effect of the steel pipe on the grout is further weakened, making it easy for microcracks, debonding slippage, and local crushing to occur at the root of the shear key, the interface area, and the end compression zone.

[0004] Existing technologies typically improve connection performance by increasing the strength of the grout, adjusting the shape of the shear keys, or increasing the number of shear keys. However, these measures mainly affect the grout or interface morphology, neglecting the constraint retention capacity and plastic energy dissipation capacity of the steel pipe material itself. In recent years, negative Poisson's ratio (NPR) materials have attracted attention due to their unique tensile expansion effect. Among them, material-type NPR steel, obtained through rare earth addition and special metallurgical processes, possesses high strength and high toughness, but its high material cost and complex manufacturing process limit its large-scale application in offshore jacket structures. Another approach to achieving negative Poisson's ratio is through geometric structural design—that is, constructing periodic cells (such as concave hexagons, arrowhead shapes, chiral structures, etc.) within the material to make the structure exhibit a negative Poisson's ratio effect macroscopically. This type of structural negative Poisson's ratio material can be prepared from conventional steel through conventional processes such as cutting, stamping, rolling, and welding, offering significant advantages such as low cost, high designability, and lightweight.

[0005] However, there are currently no reports of applying structural negative Poisson's ratio steel pipes to grouting joints. Under conditions of large diameter, high load, and long-term cyclic action, the strength, ductility, and deformation compatibility of ordinary steel pipes may still be key factors limiting the load-bearing capacity and fatigue life of grouting joints.

[0006] Therefore, there is an urgent need for a grouting connection section that can continuously maintain or even enhance circumferential restraint under high stress and large deformation conditions, improve the compressive state of the grouting material, and enhance the energy dissipation capacity of the structure. In particular, by utilizing the unique tensile expansion characteristics of structural negative Poisson's ratio steel pipes that contract laterally under axial compression, it can generate actively enhanced circumferential compression restraint on the internal grouting material, thereby improving the safety reserve and long-term service reliability of the connection parts of offshore jacket foundations. Summary of the Invention

[0007] The first aspect of this invention provides a grouting connection section based on a negative Poisson's ratio tube structure to solve the problems of reduced steel pipe constraint capacity, cracking and crushing of grout, interface debonding and slippage, and insufficient fatigue performance in traditional grouting connection sections under extreme and cyclic loads. The second aspect of this invention provides an application of the grouting connection section based on a negative Poisson's ratio tube structure.

[0008] A first aspect of the present invention provides a grouting connection section based on a negative Poisson's ratio pipe structure, comprising an outer sleeve, an inner pile pipe disposed within the outer sleeve, and high-strength grout filling an annular cavity between the outer sleeve and the inner pile pipe. A pile clamp is provided at the top end of the grouting connection section, and a grout-stopping sealing ring is provided at the bottom end of the grouting connection section. A guide wedge is also provided at the bottom of the outer sleeve. The outer sleeve is a structural negative Poisson's ratio steel pipe, and the pipe wall of the structural negative Poisson's ratio steel pipe is a steel plate with a negative Poisson's ratio cell structure. When the outer sleeve is subjected to axial pressure along its axis, the negative Poisson's ratio cell causes the outer sleeve to undergo circumferential contraction deformation, thereby applying circumferential constraint to the high-strength grout. The wall surface of the outer sleeve facing the high-strength grout forms a constraint force transmission interface.

[0009] Preferably, in the grouting connection section based on the negative Poisson's ratio pipe structure, the outer sleeve and the inner pile pipe form a constraint force transmission interface on the side wall facing the high-strength grout. Multiple shear keys are provided on the constraint force transmission interface, and the shear keys on the inner wall of the outer sleeve and the shear keys on the outer wall of the inner pile pipe are staggered, so that the high-strength grout forms a dispersed oblique compression force transmission path between adjacent shear keys.

[0010] Preferably, the grouting connection section based on the negative Poisson's ratio pipe structure is disposed between the guide leg and the outer sleeve, the lower end of the guide leg is fixedly connected to the upper end of the inner pile pipe, and the inner pile pipe is inserted into the outer sleeve; the vertical load, horizontal load and bending moment borne by the guide leg are transmitted to the outer sleeve through the outer sleeve, the high-strength grouting material and the inner pile pipe.

[0011] Preferably, in the grouting connection section based on the negative Poisson's ratio pipe structure, the height of the shear key should be no less than 5 mm, and the axial spacing of the shear keys should be no less than 50 mm.

[0012] Preferably, in the grouting connection section based on the negative Poisson's ratio pipe structure, the shear key is one or more combinations of circumferential protrusions, spiral protrusions, toothed protrusions, and wavy protrusions.

[0013] Preferably, the negative Poisson's ratio cell structure of the grouting connection section based on the negative Poisson's ratio tube structure is any one of the following: concave hexagonal cell, arrow-shaped cell, star-shaped cell, chiral cell, or rotational rigid unit cell.

[0014] Preferably, the grouting connection section based on the negative Poisson's ratio tube structure has at least one of the following on the constraint force transmission interface: a sandblasting roughening layer, a groove roughening layer, and a corrosion-resistant friction-enhancing coating.

[0015] Preferably, the high-strength grouting material in the grouting connection section based on the negative Poisson's ratio tube structure is an early-strength, micro-expansion cement-based grouting material with a 28-day compressive strength of not less than 80 MPa.

[0016] A second aspect of the present invention provides an application of a grouting connection section of a negative Poisson's ratio pipe structure for forming a marine jacket foundation structure.

[0017] The beneficial effects are: Compared with the prior art, the present invention has the following beneficial effects: 1. This invention introduces a structural negative Poisson's ratio steel pipe into the constraint boundary of the grouting connection section. Utilizing its unique tensile expansion characteristic of lateral contraction under axial compression, the outer casing exerts an actively enhanced circumferential compression constraint on the internal high-strength grouting material under axial pressure loads, unlike the constraint attenuation of ordinary steel pipes. This mechanism effectively suppresses the lateral expansion, cracking, and crushing of the grouting material, significantly improving the load-bearing capacity of the grouting connection section.

[0018] 2. The cellular structure of the structural negative Poisson's ratio steel pipe gives it excellent deformation coordination ability in the circumferential direction. It can adaptively adjust the constraint force according to the radial deformation of the grout, improve the normal contact and frictional force transmission state between the steel pipe and the grout, reduce the risk of interface debonding and slippage, and make the shear key, grout and steel pipe form a more stable synergistic force system.

[0019] 3. This invention utilizes conventional steel materials and employs conventional processes such as cutting, stamping, rolling, and welding to produce structural negative Poisson's ratio steel pipes. Compared to material-based NPR steel (which requires rare earth additives and special metallurgical processes), it offers significant cost advantages and process feasibility, facilitating large-scale application in large-diameter, long-distance projects such as offshore oil and gas and offshore wind power. Furthermore, the pore distribution resulting from the cellular structure allows for lightweighting of the connecting sections under the same constraint effect.

[0020] 4. The cellular structure of the structural negative Poisson's ratio steel pipe can precisely control the mechanical properties by adjusting geometric parameters such as concave angle, wall thickness, and cell size, so as to achieve a wide range of designable equivalent Poisson's ratio, stiffness, and yield strength, in order to meet the differentiated needs of grouting connection sections in different sea areas, water depths, and load conditions.

[0021] 5. The combination of staggered shear key arrangement, roughened interface and high-strength grout can disperse the stress concentration at the root of the inclined short column and shear key. Combined with the active restraint and energy dissipation capacity of the structural negative Poisson's ratio steel pipe, it can improve the fatigue life and impact safety reserve of the connection section under the action of wind, waves, current and unit vibration cyclic load.

[0022] Compared to ordinary steel grouted joints, this invention can provide greater deformation capacity and safety reserve while maintaining load-bearing capacity, reducing the risk of brittle failure. Furthermore, by using conventional steel and processing techniques, this invention achieves the aforementioned performance improvements while maintaining good economic efficiency and scalability. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic cross-sectional view of the present invention; Figure 3 This is a top view schematic diagram of the present invention.

[0024] Figure 4a This is a schematic diagram of the structure of a single concave hexagonal cell. Figure 4b This is a schematic diagram of a negative Poisson's ratio cell structure arranged periodically along the axial and circumferential directions of the outer sheath.

[0025] In the picture: 1. Guide leg; 2. Inner pile pipe; 3. Grouting material; 4. Outer pipe; 5. Guide wedge; 6. Pile clamp; 7. Shear key; 8. Grout sealing ring. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] In the description of this invention, it should be noted that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the system or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "setting," and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] This invention provides a grouting connection section based on a negative Poisson's ratio pipe structure, comprising an outer sleeve, an inner pile pipe disposed within the outer sleeve, and high-strength grout filling an annular cavity between the outer sleeve and the inner pile pipe. The top end of the grouting connection section is equipped with a pile clamp, and the bottom end is equipped with a grout-stopping sealing ring. The bottom of the outer sleeve is also equipped with a guide wedge. The outer sleeve is a structural negative Poisson's ratio steel pipe, and the pipe wall of the structural negative Poisson's ratio steel pipe is a steel plate with a negative Poisson's ratio cell structure. When the outer sleeve is subjected to axial pressure along its axis, the negative Poisson's ratio cell causes the outer sleeve to shrink and deform in the circumferential direction, thereby applying circumferential constraint to the high-strength grout. The wall surface of the outer sleeve facing the high-strength grout forms a constraint force transmission interface. This invention solves the problems of reduced steel pipe constraint capacity, cracking and crushing of grout, interface debonding and slippage, and insufficient fatigue performance that traditional grouting connection sections easily exhibit under extreme and cyclic loads. This invention can be prepared using conventional steel through processes such as cutting, cold bending, and welding, and has the advantages of low cost, strong design flexibility, and lightweight. It is suitable for grouting connection structures of large-diameter steel pipes such as offshore oil and gas jackets or offshore wind power jackets.

[0030] The following section uses a grouting connection section based on a negative Poisson's ratio pipe structure as an example to illustrate the entire technical process in detail.

[0031] Example 1 like Figures 1 to 3 As shown, a grouting connection section based on a negative Poisson's ratio pipe structure includes an outer sleeve 4, an inner pile pipe 2 disposed within the outer sleeve 4, and high-strength grout 3 filled in the annular cavity between the outer sleeve 4 and the inner pile pipe 2. A pile clamp 6 is provided at the top of the grouting connection section, a grout-stopping sealing ring 8 is provided at the bottom, and a guide wedge 5 is also provided at the bottom of the grouting connection section. The inner pile pipe 2 is a conventional steel pipe, and the outer sleeve 4 is a structural negative Poisson's ratio steel pipe. The pipe wall of the structural negative Poisson's ratio steel pipe is a steel plate with a negative Poisson's ratio cell structure. When the outer sleeve 4 is subjected to axial pressure along its axis, the negative Poisson's ratio cell causes the outer sleeve 4 to shrink and deform in the circumferential direction, thereby constraining the high-strength grout 3 in the circumferential direction. The wall surface of the outer sleeve 4 facing the high-strength grout 3 forms a constraint force transmission interface.

[0032] The pile clamp 6 is located at the top end of the grouting connection section. During the installation and docking stage, it is used to limit the axial relative position between the inner pile pipe 2 and the outer sleeve 4, and to assist in calibrating coaxiality. The grout sealing ring 8 is located at the bottom end to isolate the bottom gap, prevent the grout from leaking from the bottom end before it has cured, and block the injection of external seawater. The guide wedge 5 is located at the bottom of the outer sleeve 4 of the grouting connection section. It is used to provide physical guidance during the process of inserting the inner pile pipe 2 into the outer sleeve 4 during offshore hoisting, ensuring that the coaxiality of the two meets the design requirements.

[0033] The outer sleeve 4 can serve as a sleeve for steel pipe piles or skirt piles, while the inner pile pipe 2 can serve as the bottom tip of the guide leg or a skirt pile. The grouting connection section is located between the guide leg 1 and the outer sleeve 4. The lower end of the guide leg 1 is fixedly connected to the upper end of the inner pile pipe 2, and the inner pile pipe 2 is inserted into the outer sleeve 4. An annular grouting cavity is formed between the outer sleeve 4 and the inner pile pipe 2, and the annular grouting cavity is filled with high-strength grouting material 3. The vertical load, horizontal load, and bending moment borne by the guide leg 1 are transmitted to the outer sleeve 4 through the outer sleeve 4, the high-strength grouting material 3, and the inner pile pipe 2.

[0034] The grouting connection section can be adapted to either the pre-piling or post-piling construction process according to actual engineering needs: When using the pre-piling method, the outer casing 4 (steel pipe pile) is first driven into the seabed, and then the entire structure with the inner pile pipe 2 (bottom tip of the guide pipe leg) is hoisted and inserted into the outer casing 4, and grouting is performed in the annular cavity between the outer casing 4 and the inner pile pipe 2 to form a connection; when using the post-piling method, the guide frame structure with the outer casing 4 (skirt pile sleeve) is first sunk onto the seabed, and then the inner pile pipe 2 (skirt pile) is inserted into the outer casing 4 from the top and driven into the seabed, followed by annular cavity grouting. For the pre-piling method, the pile clamp 6 and the grout-stopping sealing ring 8 are both installed on the inner pile pipe 2; for the post-piling method, the pile clamp 6 and the grout-stopping sealing ring 8 are both installed on the outer casing 4. In both construction methods, the pile clamp 6, the grout-stopping sealing ring 8, the guide wedge 5, and the negative Poisson's ratio outer casing 4 all play corresponding positioning, leakage prevention, guiding, and active circumferential restraint roles.

[0035] The negative Poisson's ratio cell structure is any one of the following: concave hexagonal cell, arrow-shaped cell, star-shaped cell, chiral cell, or rotationally rigid unit cell. Multiple negative Poisson's ratio cell structures with the same configuration are arranged periodically along the axial and circumferential directions of the outer sleeve 4.

[0036] As one specific implementation method, such as Figure 4a and Figure 4b As shown, the negative Poisson's ratio cell structure employs concave hexagonal cells, and multiple concave hexagonal cells are periodically arranged along the axial and circumferential directions of the outer sleeve. Each concave hexagonal cell includes two symmetrically arranged concave sides, which form a concave angle with the axial direction of the outer sleeve 4. This concave angle is preferably 10° to 60°. The wall thickness of the concave hexagonal cell is preferably 0.5 mm to 5 mm, and the axial dimension of a single cell is preferably 5 mm to 50 mm.

[0037] The aforementioned geometric parameters cause the steel pipe to produce a significant lateral shrinkage effect when subjected to axial compression, and the equivalent Poisson's ratio and stiffness can be precisely controlled by adjusting the parameters.

[0038] The structural negative Poisson's ratio steel pipe is formed from conventional steel (such as DH36, DH420, etc.) through stamping, cold bending, laser cutting, or 3D printing processes to create the negative Poisson's ratio cell structure, and then rolled and welded. This manufacturing path does not require special metallurgical processes, significantly reducing material costs and manufacturing difficulty.

[0039] like Figure 2 and Figure 3 As shown, the outer casing 4 and the inner pile pipe 2 form a constraint force transmission interface on the side wall facing the high-strength grouting material 3, and multiple shear keys 7 are set on the constraint force transmission interface.

[0040] The height of the shear key 7 should be no less than 5mm, and the axial spacing of the shear key 7 should be no less than 50mm.

[0041] The shear key 7 can be one or a combination of circumferential protrusions, spiral protrusions, toothed protrusions, and wavy protrusions. The shear keys 7 on the inner wall of the outer sleeve 4 and the shear keys 7 on the outer wall of the inner pile pipe 2 can be staggered axially and / or circumferentially. This staggered arrangement creates multiple dispersed, obliquely compressed short columns between adjacent shear keys, which helps reduce stress concentration at the root of the shear key 7 and in localized areas of the high-strength grout 3, resulting in a more dispersed oblique compression force transmission path within the high-strength grout 3. Specific dimensions can be determined based on the diameter of the connecting section, the thickness of the annular cavity, the design axial force, the design bending moment, the fatigue load spectrum, and the strength grade of the grout. The shear key 7 can be integrally formed with the structural negative Poisson's ratio steel pipe.

[0042] The wall surfaces of the outer casing 4 and inner pile pipe 2 in contact with the high-strength grout 3 can be treated with sandblasting, grooving, or rolling texture, or a corrosion-resistant friction-enhancing coating can be applied. That is, the constraint force transmission interface is provided with at least one of the following: sandblasting roughening layer, grooving roughening layer, and corrosion-resistant friction-enhancing coating. The above treatment can improve the interface roughness and friction coefficient, enhance the mechanical interlocking ability between the high-strength grout 3 and the steel pipe wall after curing, and help reduce interface slippage under load, so as to improve the bonding and friction force transmission ability between the structural negative Poisson's ratio steel pipe and the high-strength grout 3.

[0043] High-strength grouting material 3 is an early-strength, micro-expansion cement-based grouting material with a 28-day compressive strength of not less than 80 MPa, and it has anti-segregation and self-compacting properties. During construction, high-strength grouting material 3 is injected into the annular cavity through a grouting pipe and vented through a venting pipe to ensure that the annular cavity is filled densely.

[0044] The working mechanism of the invention is as follows: When the grouting connection section is subjected to the main load of axial pressure, the load is transmitted through the outer sleeve 4, the inner pile pipe 2, the shear key 7, and the high-strength grout 3. The high-strength grout 3 near the shear key 7 forms a local compression zone and a short column under oblique pressure, while the outer sleeve 4 and the inner pile pipe 2 provide lateral restraint to the high-strength grout 3.

[0045] Because the outer casing 4 uses a structural negative Poisson's ratio steel pipe, the periodic cell structure of its pipe wall undergoes geometric deformation under axial compressive stress, driving the entire cell to contract laterally in the circumferential direction. This unique tensile expansion effect means that when the outer casing 4 is subjected to axial pressure, it does not expand outward due to the positive Poisson's ratio effect like ordinary steel pipes, thus weakening the constraint on the grouting material. Instead, it actively contracts inward, generating a continuous, and even stronger, circumferential compression constraint on the high-strength grouting material 3. As a result, the lateral expansion trend of the grouting material is effectively suppressed, the generation and propagation of its internal microcracks are delayed, and the diagonally compressed short columns near the shear key are in a more favorable triaxial compression state, thereby significantly improving the bearing capacity and ultimate deformation capacity of the connection section.

[0046] Furthermore, the cellular structure of the structural negative Poisson's ratio steel pipe gives it excellent deformation coordination capabilities in the circumferential direction. It can adaptively adjust the constraint force according to the radial deformation of the grout, maintaining the normal contact pressure and frictional force transmission capacity between the steel pipe and the high-strength grout. Deformation coordination is achieved through cellular geometric parameters, nodal stiffening, and local stability design. As a result, crack propagation, interface debonding and slippage, and local crushing near the shear key in the high-strength grout can be effectively suppressed, and the overall bearing capacity and ductility of the connection section are improved.

[0047] When the connecting section is subjected to accidental loads such as extreme wind and waves, ship collisions or earthquakes, the structural negative Poisson's ratio steel pipe can absorb a large amount of energy through the plastic buckling and folding of the cell structure, and form a synergistic energy dissipation mechanism with the high-strength grouting material and shear keys.

[0048] Example 2 The application of the grouting connection section of the negative Poisson's ratio tube structure in Embodiment 1 is used to form the offshore jacket foundation structure. That is, the grouting connection section in Embodiment 1 is used to connect the jacket leg 1 to the steel pipe pile (outer sleeve 4), or to connect the skirt pile (inner pile pipe 2) to the skirt pile sleeve (outer sleeve 4) structure.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A grouting connection section based on a negative Poisson's ratio pipe structure, comprising an outer casing (4), an inner pile pipe (2) disposed within the outer casing (4), and a high-strength grouting material (3) filling an annular cavity between the outer casing (4) and the inner pile pipe (2), characterized in that, The top end of the grouting connection section is provided with a pile clamp (6), the bottom end of the grouting connection section is provided with a grout sealing ring (8), and the bottom of the outer sleeve (4) is also provided with a guide wedge (5). The outer sleeve (4) is a structural negative Poisson's ratio steel pipe, and the pipe wall of the structural negative Poisson's ratio steel pipe is a steel plate with a negative Poisson's ratio cell structure. When the outer sleeve (4) is subjected to axial pressure along its axis, the negative Poisson's ratio cell causes the outer sleeve (4) to shrink and deform in the circumferential direction, so as to apply circumferential constraint to the high-strength grout (3). The outer sleeve (4) forms a constraint force transmission interface on the wall surface of the high-strength grout (3).

2. The grouting connection section based on the negative Poisson's ratio pipe structure according to claim 1, characterized in that, The outer sleeve (4) and the inner pile pipe (2) form a constraint force transmission interface on the side wall facing the high-strength grout (3). Multiple shear keys (7) are provided on the constraint force transmission interface. The shear keys (7) on the inner wall of the outer sleeve (4) and the shear keys (7) on the outer wall of the inner pile pipe (2) are staggered so that the high-strength grout (3) forms a dispersed oblique compression force transmission path between adjacent shear keys (7).

3. The grouting connection section based on a negative Poisson's ratio pipe structure according to claim 1 or 2, characterized in that, The grouting connection section is located between the guide leg (1) and the outer sleeve (4). The lower end of the guide leg (1) is fixedly connected to the upper end of the inner pile pipe (2). The inner pile pipe (2) is inserted into the outer sleeve (4). The vertical load, horizontal load and bending moment borne by the guide leg (1) are transmitted to the outer sleeve (4) through the outer sleeve (4), the high-strength grout (3) and the inner pile pipe (2).

4. The grouting connection section based on the negative Poisson's ratio pipe structure according to claim 3, characterized in that, The height of the shear key (7) should be no less than 5 mm, and the axial spacing of the shear key (7) should be no less than 50 mm.

5. The grouting connection section based on the negative Poisson's ratio pipe structure according to claim 4, characterized in that, The shear key (7) is one or more combinations of circumferential protrusions, spiral protrusions, toothed protrusions, and wavy protrusions.

6. The grouting connection section based on the negative Poisson's ratio pipe structure according to any one of claims 1 to 5, characterized in that, The negative Poisson's ratio cell structure is any one of the following: concave hexagonal cell, arrow-shaped cell, star-shaped cell, chiral cell, or rotationally rigid unit cell.

7. The grouting connection section based on the negative Poisson's ratio pipe structure according to any one of claims 1 to 6, characterized in that, The constraint force transmission interface is provided with at least one of the following: a sandblasted roughening layer, a grooved roughening layer, and a corrosion-resistant friction-enhancing coating.

8. The grouting connection section based on the negative Poisson's ratio pipe structure according to claim 7, characterized in that, The high-strength grout (3) is an early-strength, micro-expansion cement-based grouting material with a 28-day compressive strength of not less than 80 MPa.

9. The application of the grouting connection section of the negative Poisson's ratio pipe structure according to any one of claims 1 to 8, characterized in that, Used to form the foundation structure of offshore jackets.

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