A bionic anchoring device based on double helix structure and active adhesion mechanism

Abstract

The application discloses a bionic anchoring device based on double helix structure and active adhesion mechanism and belongs to the technical field of bionics and ocean engineering anchoring equipment. The bionic anchoring structure suitable for complex seabed is provided for the defects of large soil disturbance and passive anti-pulling failure of the existing deep water mooring anchor. The device comprises a rigid main body, double helix blades and an active adhesion triggering mechanism. The rigid main body is composed of a solid bullet head, a middle oval hollow structure and a top conical structure. The double helix blades are designed with variable pitch and diameter and are uniformly distributed with concave-convex grooves on the surface. The active adhesion triggering mechanism comprises an anchor ring and an anchor ring piston structure, and a built-in driving motor and an intelligent sensing control module are arranged in the middle part. The device realizes low disturbance penetration through double helix minimally invasive rotation and kinematic matching, triggers active adhesion when being pulled, forms deep mechanical engagement and high pressure consolidation soil shell with the soil, greatly improves the anti-pulling bearing capacity and is suitable for complex seabed such as soft mud and sand and gravel mixture.

Description

Technical Field

[0001] This invention belongs to the field of bionics and marine engineering mooring equipment, specifically relating to a bionic anchoring device based on a double helix structure and active adhesion mechanism. Background Technology

[0002] In modern marine resource development and offshore engineering, the safety of facilities such as ship anchoring and subsea pipeline fixing is crucial. Loads such as wind and waves can easily induce six-degree-of-freedom motion in structures, causing structural damage. Current mainstream deep-water mooring and anchoring technologies include dynamic penetration anchors, suction caissons, and traditional helical anchors, all of which have significant limitations in complex seabed geology. Dynamic penetration anchors are simple to construct, but the intense compression and cutting of the soil during penetration causes widespread excess pore water pressure, resulting in a significant loss of soil strength in a short period, requiring several months for consolidation and recovery. Uncontrollable depth loss can also occur during pull-out. Suction caissons offer high installation precision and minimal initial disturbance, and can withstand cyclic pull-out loads for extended periods. However, gaps can easily form between the anchor bottom and the soil, leading to loss of negative pressure suction and a significant decrease in pull-out resistance. Traditional helical anchors have high transient load-bearing capacity but rely on high-power equipment, resulting in high energy consumption and low adoption rates in deep-sea construction. The uniform cross-section helical blades are prone to disturbing the soil in extremely soft clay, causing drill jamming and idle rotation.

[0003] To address the issues of large disturbances and difficulty in dissipating pore pressure in dynamic penetration anchors, three improvement schemes have been proposed: Scheme 1 involves using high-pressure gas to extrude concrete, which bonds with the disturbed soil to enhance pull-out resistance; Scheme 2 involves creating ≤15% permeable holes in the semi-circular anchor flange to accelerate pore pressure dissipation; Scheme 3 involves modifying the anchor flange to a square shape and also incorporating permeable holes, which balances pore pressure and suppresses pull-out depth loss. However, these schemes still fail to overcome the core challenges of large-section penetrations causing significant soil disturbance and easy failure of passive pull-out resistance.

[0004] Regarding the existing implementation schemes in the aforementioned background technology, the existing technology mainly has the following defects and shortcomings: (1) Large-section blunt body penetration leads to soil structure damage, and bearing capacity is difficult to recover in a short time. When traditional dynamic penetration anchors (including modified semi-circular / square plate anchors) cut into soft clay on the seabed, the blunt body extrusion will cause a surge in positive and negative excess pore water pressure over a wide range, resulting in a sharp drop in effective soil stress and a severe reduction in undrained shear strength. The root cause of this defect is that high pull-out force requires a large cross section, and forced penetration of a large cross section will inevitably cause a physical contradiction of high disturbance. In the past, attempts to drill holes in the anchor wing could only rely on the passive drainage mechanism of the extremely low permeability coefficient of deep-sea clay, and the consolidation time was still relatively long; while internal extrusion grouting faces extremely high mechanical sealing requirements under extreme deep-sea static pressure, and is very prone to failure and leakage.

[0005] (2) Passive pull-out resistance mechanisms are difficult to withstand long-term cyclic loads and are prone to interface slip failure. Existing suction anchors and dynamic penetration anchors can only rely on the passive friction of the smooth surface of the anchor body or the negative pressure of the fixed cavity to resist pull-out forces during their service life. When encountering high-frequency and large-amplitude cyclic pull-out caused by typhoons or waves, the passive interface is prone to irreversible alternating slip debonding, leading to system failure. Traditional anchoring structures are rigid bodies that are passively subjected to force and cannot dynamically adjust their interaction with the soil according to changes in external environmental loads. Simply increasing the roughness of the outer surface or the area of ​​the anchor wings will, in turn, exacerbate the resistance and soil disturbance during the penetration stage, leading to a design dilemma. Summary of the Invention

[0006] Based on previous research on existing anchoring devices and an analysis of their problems and shortcomings, this invention aims to provide a biomimetic anchoring device based on a double-helix structure and an active attachment mechanism. This device employs a streamlined central cone combined with a double-layered smooth helical blade spatial geometry. This structure abandons the traditional compression and soil removal method, instead guiding spatial cutting along the soil's mechanical slip lines. This aims to achieve micro-disturbance, low-resistance penetration into complex strata such as deep-sea extremely soft clay, thereby maximizing the preservation of the original soil's initial shear strength and suppressing the surge in excess pore water pressure at its source. Secondly, regarding the load-bearing mechanism, this device incorporates the intelligent locking principle of underwater organisms, establishing an active attachment mechanism. When the device reaches the predetermined burial depth and is put into service under tension, it triggers a mechanical response, transforming the originally passive surface friction into deep mechanical interlocking with the surrounding undamaged original soil. Overall, a master dynamic model of spiral entry and adhesion locking is established to enhance the applicability of the device in harsh seabed environments and improve its anchoring reliability, safety, and environmental friendliness in complex seabed materials such as soft mud and gravel.

[0007] This invention provides a biomimetic anchoring device based on a double-helix structure and an active adhesion mechanism, comprising a rigid body, multiple sets of helical blades, and an active adhesion triggering mechanism. The rigid body is arranged along a longitudinal central axis, consisting of a solid bullet head, a central oval hollow structure, and a top conical structure from bottom to top. Multiple sets of helical blades are fixedly mounted on the outer surface of the rigid body, with grooves evenly distributed on the upper and lower surfaces. The active adhesion triggering mechanism includes an anchor ring and an anchor ring piston structure. The lower end of the anchor ring extends into the top conical structure, and the anchor ring piston structure is located within the top conical structure. When the anchor ring is subjected to axial pull, it can drive the anchor ring piston structure to axial displacement. A drive motor is installed inside the central oval hollow structure. The drive motor is either connected to the rigid body via a transmission connection, or the output end of the drive motor is connected to the inner wall of the rigid body using a keyless connection technology with an expansion sleeve. Torque is transmitted through static friction generated by the radial expansion of the expansion sleeve. This solution not only eliminates the need for complex keyway machining and achieves concealed zero-backlash transmission, but also generates micro-slippage under overload conditions to protect the motor from hard impact breakage.

[0008] Preferably, the top conical structure and the middle oval hollow structure are connected by a detachable flange seal, and the connection surface adopts an end face groove seal structure that combines radial sealing and axial sealing, with multiple fluororubber O-rings embedded in the groove.

[0009] Preferably, the plurality of helical blades are in two groups, and the two groups of helical blades are symmetrically distributed at 180° along the circumference of the rigid body, forming a double-threaded double helical structure.

[0010] Preferably, the spiral blade is a segmented nonlinear variable pitch structure, with the pitch gradually increasing and then gradually decreasing from bottom to top. The bottom is a small pitch centering pilot section, the middle is a large pitch soil storage section, and the top is a small pitch compaction and sealing section.

[0011] Preferably, the helical blade has a variable diameter structure, with the blade diameter gradually increasing from the bottom to the top, rotating to form an inverted conical envelope.

[0012] Preferably, the ratio of the groove depth h to the opening diameter d is in the range of 0.25 to 0.5.

[0013] Preferably, the anchor ring is circumferentially non-rigidly connected to the top conical structure and is provided with a limiting step in the axial direction. The sidewall of the anchor ring piston structure is inlaid with multiple plug seals.

[0014] Preferably, the central oval hollow structure also integrates a depth sensor, an attitude sensor, a torque sensor, an intelligent control center, and an independent energy module. Each sensor is electrically connected to the intelligent control center, and the intelligent control center is electrically connected to the drive motor.

[0015] Preferably, the rigid body adopts an asymmetrical mass distribution with a solid lower part and an open upper part, and the overall center of gravity is located in the solid bullet-shaped section.

[0016] Preferably, the bionic anchoring device rotates into the diving speed. With rotational angular velocity The following kinematic matching relationship is satisfied: ; in, Axial position The local pitch of the helical blade.

[0017] The biomimetic anchoring device based on a double helix structure and active adhesion mechanism of the present invention has the following advantages compared with the prior art: 1. For the defects caused by large-section blunt body penetration leading to soil structural damage and difficulty in restoring bearing capacity in a short time, this device abandons the blunt body plate surface and adopts a biomimetic double-helix streamlined structure and a central cone. The smooth curved surface guides the streamlined flow, allowing soil particles to slide gently, achieving minimally invasive penetration. This greatly reduces the damage to the soil's mechanical framework during penetration, suppressing the sudden increase in pore pressure at the source, and enabling the anchor body to bear load using the original soil strength without a long consolidation period after installation.

[0018] 2. Passive pull-out resistance mechanisms are prone to interfacial slippage failure due to their inability to withstand long-term cyclic loading. This device innovatively integrates active adhesion mechanisms, such as the locking mechanisms of underwater organisms like remoras and octopuses. When the device reaches the predetermined depth and withstands pull-out force, it can stimulate an active dynamic response, such as micro-mechanical interlocking, which not only increases friction but also transforms simple passive friction into deep physical engagement with the surrounding stable undisturbed soil. The greater the external pull-out force, the tighter the active gripping and engagement, thus overcoming the limitation of passive pull-out resistance being prone to slippage.

[0019] 3. Low-disturbance penetration technology with double-helix biomimetic blades and kinematic matching. This device proposes and designs a double-helix biomimetic blade structure based on a specific geometric pitch, and innovatively combines it with a no-slip kinematic diving mode, with the diving speed and rotation angular velocity strictly matched. This transforms the impact-driven or agitation-driven drilling of traditional anchoring equipment into a mimicry helical cutting approach, minimizing cutting disturbance to the undisturbed seabed soil and mechanical energy consumption during installation from both structural geometry and kinematic dimensions.

[0020] 4. Breaking through the traditional soil-structure collaborative ultimate pull-out bearing mode. The anchoring bearing mechanism of this device innovatively leaps from the traditional anchor-soil interface friction to a three-dimensional collaborative force mode of soil column gravity, consolidated shell shear, and structural interlocking. By cleverly utilizing the internal undisturbed soil column formed in the pre-process and the outer high-strength consolidated soil shell, when the active attachment mechanism is triggered, the structure is firmly interlocked in this layer of artificial hard soil. The extremely large volume of soil is transformed into the counterweight and shear defense line of the anchoring device itself, stimulating an unconventional ultimate pull-out force with extremely small structural dimensions. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall appearance structure of the biomimetic anchoring device of the present invention.

[0022] Figure 2 This is a schematic diagram of the internal longitudinal section structure of the biomimetic anchoring device of the present invention.

[0023] Figure 3 This is a schematic diagram illustrating the working process and installation dynamics of the biomimetic anchoring device of the present invention.

[0024] Figure 4 This is a graph showing the relationship between the penetration depth and installation torque of the double-helix biomimetic anchor of the present invention.

[0025] Figure 5 This is a graph showing the relationship between the penetration depth and penetration resistance of the double-helix biomimetic anchor of the present invention.

[0026] Figure 6 This is the Mises equivalent stress cloud diagram of the anchor body of the present invention.

[0027] Figure 7 This is the soil PEEQ equivalent plastic strain cloud diagram of the present invention.

[0028] In the diagram: 1-Solid bullet head; 2-Egg-shaped hollow structure in the middle; 3-Helical blade; 4-Groove; 5-Top conical structure; 6-Anchor ring; 7-Anchor ring piston structure; 8-Various electronic components. Detailed Implementation

[0029] The following detailed description of a biomimetic anchoring device based on a double helix structure and active adhesion mechanism according to the present invention is provided in conjunction with specific embodiments. The embodiments of the present invention are only used to explain the present invention and are not intended to limit the scope of protection of the present invention.

[0030] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this invention, it should be understood that if terms such as "upper," "lower," "left," and "right" 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 device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0031] Example 1 Implementation of a biomimetic anchoring device based on a double helix structure and active adhesion mechanism.

[0032] Combined with appendix Figure 1-2 As shown, the present invention provides a biomimetic anchoring device based on a double helix structure and an active adhesion mechanism.

[0033] Figure 1 This is a schematic diagram (axonometric view) of the overall appearance structure of the biomimetic anchoring device of the present invention, showing the main body shape, double helix blades and the spatial distribution of grooves. Figure 2 This is a schematic diagram of the internal longitudinal section of the biomimetic anchoring device of the present invention, revealing the connection relationship between the internal cavity, the drive motor, and the anchor ring piston structure.

[0034] This invention provides a biomimetic anchoring device based on a double helix structure and an active adhesion mechanism, comprising a rigid body, multiple sets of helical blades, and an active adhesion triggering mechanism. The rigid body is arranged along a longitudinal central axis, consisting of a solid bullet head, a central oval hollow structure, and a top conical structure from bottom to top. Multiple sets of helical blades are fixedly mounted on the outer surface of the rigid body, with grooves evenly distributed on the upper and lower surfaces of the blades. The active adhesion triggering mechanism includes an anchor ring and an anchor ring piston structure. The lower end of the anchor ring extends into the interior of the top conical structure, and the anchor ring piston structure is located within the top conical structure. When the anchor ring is subjected to axial pull, it can drive the anchor ring piston structure to move axially. A drive motor is installed inside the central oval hollow structure. The drive motor is connected to the rigid body via a transmission connection, or the motor output end is connected to the inner wall of the body using a keyless connection technology with an expansion sleeve. The radial expansion of the expansion sleeve generates a large static friction force to transmit torque. In this device, the top conical structure and the middle oval hollow structure are connected by a detachable flange seal. The connection surface adopts an end face groove seal structure that combines radial and axial sealing, and multiple fluororubber O-rings are embedded in the groove.

[0035] In this device, the multiple sets of spiral blades are divided into two sets, and the two sets of spiral blades are symmetrically distributed at 180° along the circumference of the rigid body, forming a double-threaded double-helix structure.

[0036] In this device, the spiral blades are segmented nonlinear variable pitch structures. The pitch gradually increases from bottom to top and then gradually decreases. The bottom is a small pitch centering pilot section, the middle is a large pitch soil storage section, and the top is a small pitch compaction and sealing section.

[0037] In this device, the spiral blades are of variable diameter, with the blade diameter gradually increasing from the bottom to the top, rotating to form an inverted conical envelope.

[0038] In this device, the ratio of the groove depth h to the opening diameter d of the groove is in the range of 0.25 to 0.5.

[0039] In this device, the anchor ring is circumferentially non-rigidly connected to the top conical structure and is axially provided with a limiting step. The sidewall of the anchor ring piston structure is inlaid with multiple plug seals.

[0040] The device also integrates a depth sensor, an attitude sensor, a torque sensor, an intelligent control center, and an independent energy module within its central oval hollow structure. Each sensor is electrically connected to the intelligent control center, which in turn is electrically connected to the drive motor.

[0041] In this device, the rigid main body adopts an asymmetrical mass distribution with a solid lower section and a hollow upper section, and the overall center of gravity is located in the solid bullet-shaped section. Details are as follows: Combination Figure 1 and Figure 2 As shown, this invention provides a biomimetic anchoring device based on a double helix structure and an active attachment mechanism. The overall structure is distributed with non-uniform cross-section rotational symmetry around a longitudinal central axis. The device mainly consists of three parts: a rigid body, a biomimetic double helix system, and an active attachment triggering mechanism. Rigid main body: From bottom to top, it is rigidly spliced ​​together by a solid bullet head 1, a central oval hollow structure 2, and a top conical structure 5. In order to facilitate the installation and maintenance of various internal electronic components 8, the top conical structure 5 and the central oval hollow structure 2 are set with a detachable sealed connection, which is a flange seal.

[0042] Bionic double helix system: includes two sets of helical blades 3, fixedly installed, and welded or integrally cast onto the outer surface of a rigid body. The upper and lower surfaces of the helical blades 3 are densely covered with grooves 4.

[0043] Anchor Ring and Power: The main body has a central opening at the top, and the lower end of the anchor ring 6 extends into the interior of the top conical structure 5. The two are non-rigidly connected in the circumferential direction, allowing the anchor ring to remain absolutely stationary when the anchor body rotates, i.e., free-spinning, eliminating the risk of deep-sea anchor chain entanglement. However, in the axial direction, a rotating base, i.e., a limiting step, is provided at the bottom of the extension shaft, which can lock the piston upward when pulled. There is long-term relative sliding and friction between the inner wall of the top conical structure 5 and the outer periphery of the anchor ring piston structure 7. To ensure that a sealed vacuum cavity can be formed when the piston is lifted during service, this device innovatively embeds multiple spring-energized seals (i.e., energy-storing spring composite seals) on the cylindrical surface of the piston sidewall. Various electronic components 8 are installed inside the central oval hollow structure 2, and their output shafts are drivenly connected to the main body shell to provide rotational power.

[0044] The central, oval-shaped hollow structure 2 houses the independent power and control hub of the device, integrating the following four major electronic components: 1. Core Power Module: Employing a deep-sea-grade high-torque brushless DC motor paired with a high-reduction-ratio planetary gearbox. This combination achieves a smooth transition from high speed to ultra-high torque within the limited cabin space, providing ample bottom-penetrating power for drilling into extremely soft or hard seabeds. 2. Multi-dimensional Sensor Group: Distributed depth sensors monitor descent depth, a high-precision attitude sensor (IMU) monitors verticality in real time to prevent skewing, and a main shaft torque sensor senses cutting resistance in the formation in real time. 3. Intelligent Control Center (MCU): As the system's brain, the MCU receives real-time feedback data from the multi-dimensional sensor group. In particular, utilizing a torque feedback mechanism, the MCU can dynamically adjust the frequency conversion output of the brushless DC motor, maintaining a rated constant speed during entry into soft mud areas and automatically triggering a "speed reduction and torque increase" protection program when encountering hard gravel, achieving adaptive drilling across formations. 4. Independent Energy Module: The bottom is equipped with a high-energy lithium battery pack and a battery management system (BMS) that can withstand the low temperatures of deep sea, providing a safe and abundant power guarantee for cableless independent installation.

[0045] The safety of the internal precision electronic components depends on the absolute airtightness of the cabin. At the detachable connection between the central oval hollow structure 2 and the top conical structure 5, this invention employs a deep-water-grade dual static sealing mechanism: combined with a high-strength flange bolt fastening system, the connection surface features an end-face groove sealing structure that integrates radial and axial sealing. Multiple, at least two, high-pressure-resistant and corrosion-resistant fluororubber (FKM) O-rings are embedded within the groove. When the bolts are pre-tightened and the external deep-sea hydrostatic pressure increases, the O-rings undergo adaptive elastic compression deformation within the end-face groove, completely blocking all potential capillary seepage channels. This dual static sealing mechanism can withstand long-term penetration by extreme deep-sea hydrostatic pressure, ensuring the internal electronic cabin maintains an absolutely dry, normal-pressure or slightly negative-pressure environment, significantly extending the service life of the internal intelligent components.

[0046] The overall axial length of the biomimetic anchoring device of this invention is set at 2300 mm. The specific dimensions and axial proportions of each segment of the rigid body from bottom to top are as follows: Solid bullet head 1: axial length approximately 485mm, accounting for about 20% of the total axial length of the anchor body. This proportion is designed to ensure sufficient mass distribution at the bottom for gravity guidance; The central oval hollow structure 2 has an axial length of approximately 1115 mm, accounting for about 50% of the total axial length of the anchor body. This section is the longest, providing ample installation space for various internal electronic components 8. Top conical structure 5: axial length approximately 700mm, accounting for about 30% of the total axial length of the anchor body. This section provides ample space for the top anchor ring piston system.

[0047] In terms of radial dimensions, the maximum radial outer diameter of the rigid body, i.e., the thickest part of the oval structure, is approximately 500 mm; while the maximum radial unfolded outer diameter of the spiral blades 3 of the external biomimetic double helix system is approximately 2250 mm. This significant difference in radial dimensions further amplifies the soil-locking space, providing reliable geometric support for high-strength active adhesion.

[0048] The asymmetrical center-of-gravity distribution of the roly-poly vertical guide ensures that the device does not flip during free descent to a depth of 100 meters in the deep sea, and precisely cuts into the seabed in an absolutely vertical posture. For example... Figure 2 As shown in the cross-sectional view, the bottom uses a solid bullet-shaped structure 1 to greatly increase the weight and mechanical strength of the bottom structure; while the middle oval hollow structure 2 and the top conical structure 5 are both hollow. This asymmetrical mass distribution, solid at the bottom and hollow at the top, forcibly lowers the geometric center of gravity of the entire device to the lowest point. Utilizing a gravity-guided principle similar to that of a roly-poly toy, under the combined effects of hydrodynamics and gravity, the device can always maintain a vertically downward-facing posture as it penetrates the seabed.

[0049] The micro-disturbance cutting and soil-locking space construction based on the variable-parameter double helix can efficiently drill without causing a large-scale surge in pore water pressure, and retain the original soil mass to provide friction for subsequent drilling. Figure 2 As shown, two sets of helical blades 3 are arranged at intervals along the central axis, forming a double helix structure resembling a shark egg case. The double-threaded design achieves a larger lead at the same rotational speed, thus significantly increasing the efficiency of guiding the material to the seabed.

[0050] Variable pitch design: The pitch of the helical blade 3 gradually increases from bottom to top. The extremely small pitch at the bottom allows for a larger contact area between the blade and the soil during the pilot cutting stage, providing stable and accurate positioning and centering. As the cutting deepens, the gradually increasing pitch at the top expands the borehole and traps soil, creating a large soil-locking space, which is the chip removal space in traditional machining. At the same time, the increased pitch leads to a smaller helix angle, making the path of the cut substrate extremely meandering and reducing soil removal efficiency. This design aims to trap the substrate between the blades.

[0051] Variable diameter design: The diameter of the spiral blade 3 gradually increases from bottom to top of the main body, with the smallest diameter at the bottom being about 1 / 3 of the main body height, and the largest diameter at the connection between the top cone and the middle part being about 4 / 5 of the main body height. This inverted conical rotating envelope surface creates a huge physical gap between itself and the outer wall of the main body, which is completely filled with substrate such as soft mud or gravel, achieving a natural self-locking phenomenon similar to that of a screw being screwed into wood.

[0052] The specific structural parameters are as follows: Double-line symmetrical layout and thickness: The initial phase angles of the two helical blades are 180° and 360°, respectively, maintaining a constant 180° symmetrical distribution along the circumference of the main body. This centrally symmetrical double-line thread structure effectively eliminates eccentric moments, ensuring absolute perpendicularity during penetration. The blade body thickness is set at 20mm to ensure structural rigidity when cutting through high-strength hard soil layers.

[0053] Lead and Variable Pitch Gradient: Due to the use of a double-start thread, the local lead L of the device is equal to twice the local pitch P, i.e., L = 2P. The two helical blades employ a segmented nonlinear variable pitch design along the axial height H: In the initial pilot section, H = 0-400mm: the lowest pitch is 500mm, corresponding to a lead of 1000mm, and increases uniformly with increasing height. At a height of 400mm, the pitch increases to 1000mm, corresponding to a lead of 2000mm. During this stage, the pitch increase gradient is 1.25mm / mm, and the relatively small initial pitch provides excellent centering cutting capability.

[0054] In the transitional expansion section, H=400-600mm: the pitch rapidly increases from 1000mm to 1500mm, with a pitch increase gradient of 2.5mm / mm. This large gradient change in this section aims to quickly expand the substrate, creating a large space for soil containment and locking in the upper part.

[0055] Main soil stabilization section, H=600-1800mm: The pitch remains constant at the global maximum of 1500mm, corresponding to a maximum lead of 3000mm. The ultra-large lead, combined with the gradually increasing blade diameter in this section, causes a large amount of the cut soft mud to be trapped in the blade gaps.

[0056] In the top compacted and closed section, from H>1800mm to the top: the pitch gradually decreases from 1500mm, dropping to 750mm at the top end, corresponding to a lead of 1500mm. This negative pitch gradient change in this stage, specifically a decrease, can generate a secondary longitudinal downward compression on the soil entrained between the blades at the end of installation, further compacting and consolidating the soil crust.

[0057] Helix angle characteristics: The helix angle α at any point on the helical blade follows a geometric relationship. , where D is the envelope diameter of the horizontal plane where the point is located. As the lead of the main soil storage section remains at a maximum value and the diameter gradually increases, the helical rise angle of the external soil sliding along the blade gradually decreases, thereby effectively reducing the soil discharge rate and causing the bottom material to be passively retained inside the device.

[0058] Soil compaction / flow rate equation: In the formula, This represents the rate of change in net volume. The inflow volumetric flow rate; The outflow volumetric flow rate; To control the area of ​​effect; The angular velocity of the drill bit rotation; Lower pitch; This represents the upper pitch. When seabed mud is compressed, it can be considered a continuous medium containing pore water, a non-Newtonian fluid. According to the continuity equation of mass conservation, the volume of matter flowing into a space per unit time minus the volume flowing out equals the rate of change of the volume of matter within that space.

[0059] Therefore, the lower layer pitch Greater than the upper pitch This means that the bottom leaves take in more soil than the top leaves expel. Due to the law of conservation of mass, the excess soil has nowhere to go but is forced to be squeezed in the space between the leaves, causing pore water to drain out, the void ratio to drop sharply, and thus compaction and hardening.

[0060] The main soil storage section, with a height of 600-1800mm, features a significantly increased pitch of 1500mm, coupled with a variable diameter design. This large pitch generates a large lead, resulting in a wider blade spacing. Geometrically, this creates a massive soil-accommodating space. Under the matching penetration theory, a large volume of undisturbed soft mud enters this space along the slip line, greatly increasing the counterweight of the soil column during subsequent uplift resistance.

[0061] When the top height exceeds 1800mm, the pitch abruptly drops from 1500mm to 750mm. Theoretical proof: by introducing the principles of mass conservation and volumetric strain, the lower part transports 1500mm of soil upwards per rotation, while the top part only discharges 750mm of soil per rotation. The inlet flow rate is far greater than the outlet flow rate, thus forming a physically dynamic compression chamber. This ensures at least the soil around the anchor body is compacted.

[0062] This invention is based on the mechanical-solid dual-effect active attachment of piston-groove linkage, which can overcome the defects of traditional smooth anchor plates that are prone to slippage during pull-out, and enable the device to actively and firmly grip the surrounding soil when under tension.

[0063] Microscopic interface resistance amplification: The grooves 4 set on the surface of the spiral blade 3 increase the physical interlocking friction with the bottom material entering the soil-locking space when under load; on the other hand, they restrict the relative sliding of the bottom material being cut.

[0064] Macroscopic mechanical solid triggering: such as Figure 2 As shown, the anchor ring 6 is not directly and rigidly connected to the shell, but rather acts as a force-bearing actuator, with its bottom end connected to the anchor ring piston structure 7. A limiting plate is installed inside the top conical structure 5 to limit the maximum stroke of the anchor ring piston structure 7 and protect the structure. When the upper anchor chain is pulled by waves, the upward pulling force first causes the anchor ring 6 and the extension shaft base to lock the anchor ring piston structure 7, causing it to displace upwards within the cavity and perform a suction action. When the piston reaches its maximum stroke, the piston base and the upper limiting ring make rigid physical contact and lock together. The ultimate pull-out load is transferred to the robust anchor body shell, effectively protecting the internal dynamic seals from tensile damage. At this time, the gravity of the seabed within the soil-locking space, the mechanical friction of the grooves 4, and the effective cohesion between the soil surrounding the anchor body and the surrounding soil after its arrangement are combined, causing the device to generate a huge active adhesion force exceeding its own size, providing sufficient and fatigue-resistant anchoring force for the marine structure.

[0065] To maximize the activation of the soil-soil internal shear failure mechanism while taking into account the overall structural stiffness of the helical blade, this invention precisely constrains the spatial geometric parameters of the grooves 4 on the surface of the helical blade 3. Setting the opening diameter of a single groove as d and the maximum depression / protrusion depth as h, the ratio of groove depth to diameter (h / d) is preferably limited to between 0.25 and 0.5.

[0066] 1. Verification of soil plug force equilibrium at the lower threshold (h / d < 0.25): Assume the substrate filling the groove is a microscopic cylindrical soil plug. To overcome the slipover asperities failure of traditional anchors, the following condition must be met: the interfacial pull-out force of the soil plug sidewall is greater than the internal shear force of the soil at the opening, i.e., satisfying the derived equation. Due to the internal strength of the soil Always greater than the interface strength The critical solution of this equation is h / d ≥ 0.25. This formula mathematically verifies that only when the ratio is greater than 1:4 can the shear failure surface be forced to shift outward, triggering the Mohr-Coulomb shear strengthening theory.

[0067] 2. Verification of the Terzaghi Arching effect at the upper threshold (h / d≥0.5): According to Terzaghi's one-dimensional pore arching theory, stress transfer within a confined space follows an exponential decay function. If the depth-to-diameter ratio (h / d) is too large, soil particles will become strongly interlocked at the borehole opening, forming a mechanical arch that shields the external compressive force, preventing the trench bottom from being densely filled. By limiting the upper limit to 0.5, the conditions for the soil arching effect are effectively suppressed, ensuring that the external substrate can be 100% densely filled to the trench bottom during double-helix cutting. Furthermore, from a materials mechanics perspective, h / d ≤ 0.5 effectively limits the stress concentration factor at the blade root. This ensures structural safety during high-torque screwing-in.

[0068] When the device cuts in, the approximate calculation process of the chip removal space described above is as follows: 1. To quantify the calculation, first define the geometric parameters of each part: H: Total height of the entire structure (vertical distance from bottom to top); D: Maximum outer diameter of the helical blades (diameter of the largest circle formed by the blades rotating); d: Outer diameter of the central body (diameter of the central cylinder / cone); t: Thickness of the helical blades; n: Number of helical blades; p: Pitch of the helix (vertical distance between corresponding points of two adjacent blades); If the top of the central body is a cone, the height of the cone needs to be added. and bottom diameter .

[0069] 2. Calculate the volume of the entire enclosed space, which is approximated as a cone (with the maximum outer diameter). .

[0070] 3. Calculate the volume of the central main body, which is approximately a cylinder with a cone at the top. Volume of a cylinder: ,in ; Volume of a cone: ; Volume of the main body in the middle section: .

[0071] 4. Calculate the volume of a single set of helical blades. The helical blade can be approximated as a solid helical surface with a thickness t. When calculating the volume of a single set of blades, it can be decomposed into the product of the unfolded helical surface and the thickness.

[0072] First, calculate the unfolded area of ​​a single-turn helical blade: the length L of the helix can be derived from the pitch p and the circumference. The length of a single-turn helix... Approximate lateral surface area of ​​a single set of helical blades: Volume of a single set of helical blades: Since there are two sets of helical blades, the total blade volume is: ; 5. Calculate the void volume of the helical blade. The final void volume is the overall enclosed volume minus the volume of the central body and the volume of all blades: .

[0073] Example 2: The action relationship and working process of a biomimetic anchoring device based on a double helix structure and active adhesion mechanism.

[0074] Combined with appendix Figure 3 The workflow shown is as follows: Figure 3 This is a schematic diagram illustrating the working process and installation dynamics of the biomimetic anchoring device of the present invention, showing the entire process from the device diving into the water, contacting the seabed and spiraling in, until it is anchored in place.

[0075] The actual operation and dynamic response process of this device are as follows: Step 1: Descent and Implantation Figure 3 On the left. The surface construction vessel uses an anchor chain to lift the anchor ring 6 and lower the device. After being released into the water, under the high gravity traction of the solid bullet head 1 and the guiding effect of the top conical structure 5, the device falls vertically with minimal water resistance and smoothly penetrates the seabed surface relying on its initial kinetic energy.

[0076] Step 2: Spiral cut in. Figure 3 In the middle. The electronic component / drive motor installed in the middle is activated. The motor output torque drives the entire rigid body and the spiral blades 3 to rotate slowly. The small-pitch blades at the bottom first make a micro-cut in the soil. As the device continues to spiral in, the soft mud on the seabed slides along the double spiral, is guided by the winding path and fills the ever-expanding soil-locking space above, until the device is completely submerged in the seabed.

[0077] Step 3: Active locking in place. Figure 3The right side and the undrawn stress states. After the device is installed, the motor power is cut off, and it enters service mode. When ocean currents or typhoons cause the sea surface platform to generate a huge upward pull force, and the anchor ring 6 is pulled by the anchor chain, the anchor ring moves slightly upward. At this time, the anchor ring piston structure 7 is triggered to lift. When the piston moves to its maximum stroke, the piston base and the upper limit retaining ring make rigid physical contact and lock. The ultimate tensile load is transferred to the robust anchor body shell, thereby effectively protecting the internal dynamic seals from tensile damage. The groove 4 is filled with soil, firmly gripping the soil in the soil-locking space. At this time, the anchor body and the soil are integrated, generating a huge anchoring force for the structure.

[0078] The Mohr-Coulomb shear strengthening theory of biomimetic grooved interfaces: Traditional smooth dynamic penetration anchors often fail by slippage at the metal-soil interface under ultimate tensile stress. This invention uses densely packed grooves 4 on the surface of the helical blade, altering the mechanical transmission path at the failure surface. Based on the Mohr-Coulomb strength criterion and the effective stress principle, the shear strength of the failure surface... Evolved into: ; In the formula, It is the ultimate shear strength; The effective stress is in the normal direction; The effective internal friction angle; For effective cohesion, due to the mechanical embedding effect of the grooves, the passive slip line, originally located on the smooth metal surface, is forced to move outward to the area between the soil embedded in the grooves and the outer consolidated soil shell, resulting in soil-soil shear failure rather than iron-soil friction. At this point, the effective friction angle of the interface... 'and effective cohesion All parameters were equivalently amplified to approximate the internal parameters of the undisturbed hardened soil. This theory confirms that the micro-groove design can effectively eliminate the engineering risks of interfacial degumming and slippage, achieving extremely high mechanical interlocking.

[0079] The initial porosity of undisturbed deep-sea mud is extremely high, resulting in its natural... 'and The level is extremely low. The variable-pitch double-helix structure of this invention generates strong radial displacement and forced compression of the surrounding soil upon penetration. According to geotechnical mechanics, this process forcibly discharges pore water from the soil, significantly reducing the local void ratio. The smaller the void ratio, the denser the soil, and the stronger the interlocking between particles, greatly increasing the overconsolidation ratio (OCR), which is the ratio of the maximum effective stress the soil has historically experienced to the current effective stress. This change in physical state causes the effective internal friction angle of the consolidated soil shell surrounding the anchor body to increase. 'and effective cohesion Compared to undisturbed soil, this represents a leap in magnitude. The interlocking grooves lock the shear surface within the soil, thereby unleashing an ultimate pull-out force far exceeding that of conventional interfaces.

[0080] Example 3 Based on Examples 1 and 2, simulation experiments are conducted.

[0081] Combined with appendix Figure 4-7 As shown, Figure 4 This is a graph showing the relationship between the penetration depth and installation torque of the double-helix biomimetic anchor of the present invention. Figure 5 This is a graph showing the relationship between the penetration depth and penetration resistance of the double-helix biomimetic anchor of the present invention. Figure 6 This is the Mises equivalent stress cloud diagram of the anchor body of the present invention. Figure 7 This is the soil PEEQ equivalent plastic strain cloud diagram of the present invention.

[0082] To verify the practicality and effectiveness of this invention, multiple numerical simulation experiments were conducted. The main results of one experiment are shown in the appendix. Figure 4-7 As shown, we will now use an example of a marine construction operation to describe this simulation experiment, as follows: The workflow is divided into three continuous stages: low-resistance screwing in, soil discharge and compaction, and passive consolidation and pull-out resistance.

[0083] Phase 1: Kinematic Matching and Low-Resistance Spiraling, i.e., the installation phase. First, underwater robots and other equipment pull the anchoring device to the designated seabed. The drive motor then propels the anchor body smoothly into the soil along the double helical blades at the bottom, maintaining a speed precisely matched to the geometric pitch of the helical blades. Computer fluid-structure interaction simulation data is attached. Figure 4 The torque curves show that, in a 1:10 scale model, the maximum installation torque of the device is only about 171 N·m. Based on the dimensional similarity criterion, the maximum installation torque of the 1:1 full-size prototype is expected to be approximately 171 kN·m.

[0084] The second stage: Double-helix soil removal and deep consolidation, i.e., the environmental remodeling stage. As the anchor continues to spiral into a deep burial state, the double-helix blades do not break up or hollow out the soil; instead, they strongly push the cut-off undisturbed soil radially in all directions. Simulation data is attached. Figure 5 The resistance curve in the figure shows that the steady-state penetration resistance at the bottom of the 1:10 scale model reaches approximately 550 N. Simultaneously, combined with the internal force and equivalent plastic strain contour plots, as shown in the attached figure... Figure 7 The diagram clearly demonstrates that this enormous compressive force has forcibly created an extremely dense, high-pressure consolidated soil shell around the anchor body.

[0085] The third stage: Soil-structure synergy and ultimate pull-out resistance, i.e., the load-bearing stage. This invention employs a highly reliable and minimalist design with no moving mechanical parts. Once the anchor reaches the target depth and is fixed under force, its ultimate pull-out resistance is entirely generated by the physical mechanism of soil-structure synergy. When the top pull ring is subjected to a huge upward pulling load, its pull-out bearing capacity is composed of the following three superimposed mechanisms: 1. Soil column self-weight effect: During the screwing process, the gap between the double helix blades and the main body is completely filled with dense soil. Pulling the anchor upwards is equivalent to simultaneously uprooting this heavy and solid integral soil column inside; 2. Super strong interfacial friction: Due to the extreme outward compaction of the surrounding soil in the second stage, the dense soil tightly hugs the anchor body, resulting in a huge sliding friction resistance between the wide blade surface and the hardened soil. 3. Shear interlocking of the consolidated soil shell, core resistance: the high-pressure consolidated soil shell around the anchor body that is compressed and formed, as shown in the attached figure. Figure 7 As shown in the highlighted area of ​​the PEEQ cloud map, it looks like a solid cement mold has jammed the double-helix blades. To forcibly pull out the anchor, the surrounding layer of artificial hard soil must be sheared and destroyed.

[0086] The following conclusions were drawn from the simulation data: 1. The torque curve shows that the maximum torque of the 1:10 model during deep burial remained stable at around 171 N·m, without any severe oscillations throughout the process; (The text also includes a note about torque curves and a model model.) Figure 6 The Mises cloud map shows that the high-stress zone is symmetrically bulb-shaped with no stress eccentricity. This means that, with the geometric pitch and diving speed matched, it can precisely and vertically cut into the seabed. It overcomes the fatal shortcomings of traditional piling or large-area soil mixing equipment, such as high energy consumption and easy deviation.

[0087] 2. The model's drag curve stabilized at a high level of 550N during the later stages of descent, consistent with the characteristic that the seabed becomes increasingly solid with depth. More importantly, the PEEQ cloud map—the deep red high-plastic deformation zone—firmly adhered to the outer perimeter of the anchor, forming a regular cylinder, while the surrounding soil remained the original deep blue soil. This indicates that the double-helix blades forcefully compressed the cut soil outwards, radially, creating a dense, hard artificial consolidation crust around the anchor. Furthermore, the surrounding plastic deformation zone was well controlled, minimizing the impact on the seabed environment and only locally reinforcing the soft soil.

[0088] Fluid-structure interaction simulation data demonstrate that this invention achieves stable penetration with low energy consumption, as shown in the attached figure. Figure 4 , 5 As shown, it not only causes minimal damage to the original soil, but also reconstructs a high-strength, dense, consolidated soil shell around the anchor body through the radial soil discharge effect, as shown in the attached figure. Figure 6, 7 As shown, this provides a mechanical basis for the subsequent simplified high-strength pull-out mechanism.

[0089] Kinematic matching equations: In the formula, The speed at which the biomimetic anchoring device rotates into the submersion zone; It is the rotational angular velocity; Axial position The local pitch of the helical blades. In marine geotechnical engineering, the installation of helical piles (anchors) has an ideal state called pitch-matched installation. When the rigid body's descent speed... With rotational angular velocity When the ratio is exactly twice the lead P of the helical blade, the blade cuts into the soil with its own helical surface. This theoretically explains the micro-disturbance cutting-in of the present invention.

[0090] Taking the average pitch of this design as 1000mm (i.e., the initial lead L is 2.0m), and substituting into the above formula, the optimal rotational speed is 12RPM. Therefore, the precise diving speed for underwater robots or crane control must be locked at: Under the strict kinematic matching of 12 RPM and 0.4 m / s, the bottom helical blade can be screwed into the seabed in complete accordance with its own geometric curvature, keeping the macroscopic cutting slip ratio close to zero.

[0091] For extremely soft clay layers in the deep sea, such as high-water-content silt or poor-quality calcareous sand: Control strategy: self-weight servo rated rotary entry. This type of substrate has low shear strength, typically <10 kPa, and the effective gravity Wa of the device itself is much greater than the end penetration resistance. Motion parameters: The drive motor maintains the rated high speed n=12 RPM based on the design benchmark. According to the kinematic matching equation... ,by The anchor is lowered at a constant speed of 0.4 m / s. During this stage, the anchor body relies entirely on the perfect match between its own weight and the rated rotation speed to achieve a rapid and smooth entry with minimal disturbance.

[0092] For gravel-gravel mixed layers or hard clay layers: Control strategy, torque feedback adaptive deceleration cutting: When encountering high-hardness seabed, the end penetration resistance surges, and relying solely on its own weight cannot maintain a descent speed of 0.4 m / s. Forcing a high speed of 12 RPM will inevitably cause the propeller blades to slip in place, i.e., drill clogging, disrupting the no-slip matching and severely disturbing the formation. Therefore, when the seabed is detected to be a gravel-gravel mixed layer or hard clay layer, the device uses a low-speed, high-torque cutting mode. Motion parameters: The control system actively linearly reduces the motor speed n to a low-speed range, recommended to be n = 3-5 RPM. According to the matching formula, the descent advance speed... The speed must be simultaneously reduced to 0.05-0.083 m / s. Under this low-speed matching condition, because the bottom pilot blade with the extremely small pitch is embedded in the hard substrate, the helical surface generates a micro-mechanical inclined thrust, much like a jack, as it rotates slowly. This powerful self-propelled pulling force replaces the missing external downward pressure (WOB), pulling the entire anchor body at a tiny step speed of 0.05 m / s, gradually cutting through and squeezing into the gravel layer.

[0093] It should be noted that this device is primarily designed for complex deep-sea sediments with a certain degree of plasticity or machinability, such as soft mud, silt, gravel, and ultra-consolidated clay. It is not optimally suited for large areas of exposed bedrock or dense, non-porous reef seabeds.

[0094] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0095] The above embodiments are merely illustrative examples and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A biomimetic anchoring device based on a double helix structure and an active adhesion mechanism, characterized in that, Includes a rigid body, multiple sets of spiral blades, and an active attachment triggering mechanism; The rigid body is arranged along the longitudinal central axis, and from bottom to top, it consists of a solid bullet head, a hollow oval structure in the middle, and a conical structure at the top. Multiple sets of spiral blades are fixedly mounted on the outer surface of the rigid body, and grooves are evenly distributed on the upper and lower surfaces of the spiral blades. The active attachment triggering mechanism includes an anchor ring and an anchor ring piston structure. The lower end of the anchor ring extends into the interior of the top conical structure, and the anchor ring piston structure is located inside the top conical structure. When the anchor ring is subjected to axial pull, it drives the anchor ring piston structure to move axially. A drive motor is installed inside the central oval hollow structure. The drive motor is connected to the rigid body through transmission, or the output end of the drive motor is connected to the inner wall of the rigid body through a keyless connection technology using a shrink sleeve. The torque is transmitted by static friction force generated by the radial expansion of the shrink sleeve.

2. The biomimetic anchoring device based on a double helix structure and active adhesion mechanism according to claim 1, characterized in that, The top conical structure and the middle oval hollow structure are connected by a detachable flange seal. The connection surface adopts an end face groove seal structure that combines radial and axial sealing, and multiple fluororubber O-rings are embedded in the groove.

3. The biomimetic anchoring device based on a double helix structure and active adhesion mechanism according to claim 1, characterized in that, The multiple sets of spiral blades are divided into two sets, which are symmetrically distributed at 180° along the circumference of the rigid body, forming a double-threaded double-helix structure.

4. The biomimetic anchoring device based on a double helix structure and active adhesion mechanism according to claim 1, characterized in that, The spiral blades are segmented nonlinear variable pitch structures. The pitch gradually increases from bottom to top and then gradually decreases. The bottom is a small pitch centering pilot section, the middle is a large pitch soil storage section, and the top is a small pitch compaction and sealing section.

5. The biomimetic anchoring device based on a double helix structure and active adhesion mechanism according to claim 1, characterized in that, The spiral blade has a variable diameter structure, with the blade diameter gradually increasing from the bottom to the top, rotating to form an inverted conical envelope.

6. The biomimetic anchoring device based on a double helix structure and active adhesion mechanism according to claim 1, characterized in that, The ratio of the groove depth h to the opening diameter d of the groove is in the range of 0.25 to 0.

5.

7. The biomimetic anchoring device based on a double helix structure and active adhesion mechanism according to claim 1, characterized in that, The anchor ring is circumferentially non-rigidly connected to the top conical structure and is axially provided with a limiting step. The sidewall of the anchor ring piston structure is inlaid with multiple plug seals.

8. The biomimetic anchoring device based on a double helix structure and active adhesion mechanism according to claim 1, characterized in that, The central oval hollow structure also integrates a depth sensor, an attitude sensor, a torque sensor, an intelligent control center, and an independent energy module. Each sensor is electrically connected to the intelligent control center, which is in turn electrically connected to the drive motor.

9. A biomimetic anchoring device based on a double helix structure and active adhesion mechanism according to claim 1, characterized in that, The rigid body adopts an asymmetrical mass distribution with a solid lower part and an open upper part, and the overall center of gravity is located in the solid bullet-shaped section.

10. A biomimetic anchoring device based on a double helix structure and active adhesion mechanism according to claim 1, characterized in that, The biomimetic anchoring device rotates into the diving speed With rotational angular velocity The following kinematic matching relationship is satisfied: ； in, Axial position The local pitch of the helical blade.

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