Seabed sand liquefaction test system

Abstract

The invention provides a seabed sand liquefaction test system, which relates to the technical field of underground or underwater structures and comprises a mounting platform, a buoyancy system, an excitation system, a probe rod and a penetration system. Wherein all the systems are installed on an installation platform, and the platform is connected with an overwater facility through a cable. The excitation system and the penetration system are stacked and connected through a floating connecting structure, and the probe rod sequentially penetrates through the excitation system and the penetration system; the penetration system is provided with a penetration power unit, a transmission mechanism, a symmetrical double-head rocker arm and a feeding wheel, the transmission mechanism is connected with a torque retainer in series, and a reversing mechanism is arranged and can drive the rocker arm to move in a mirror image mode, so that the feeding wheel clamps the feeler lever to achieve penetration or lifting. The floating connection isolates vibration and prevents resonance and data noise; the torque retainer realizes fixed-torque clamping and is simplified into a single-power unit, so that the cost is reduced, and faults are reduced; the rocker arm can release the probe rod, retention is achieved without auxiliary equipment, lifting, slipping and clamping stagnation are prevented, and the testing efficiency, reliability and data precision are improved.

Description

Technical Field

[0001] This application relates to the field of underground or underwater structures, specifically to a seabed sand liquefaction testing system. Background Technology

[0002] With the continuous increase in global offshore oil and gas resource exploration and development, shallow seas and nearshore areas have become core areas for the construction of infrastructure such as offshore drilling platforms, subsea oil and gas pipelines, and submarine cables. However, seabed sand liquefaction, as a typical marine engineering geological hazard, has induced seabed instability phenomena such as sandy seabed slippage, shallow foundation structure damage, and pipeline floating and tilting, which have repeatedly led to major engineering accidents and caused economic losses. Therefore, in-situ monitoring and liquefaction potential assessment of the seabed sand liquefaction process have become key technical links in ensuring the safety of marine engineering.

[0003] Currently, testing technologies for seabed sand liquefaction both domestically and internationally are mainly developed based on the principles of terrestrial sand liquefaction testing. The core idea is to simulate liquefaction-inducing loads, such as wave loads and platform self-vibration loads, and combine these with in-situ monitoring parameters to determine the liquefaction characteristics of the sand. Among these, the testing method combining static cone penetration testing and vibration simulation has become the mainstream technology due to its advantages of in-situ accuracy, continuity, and timeliness.

[0004] Early seabed sand liquefaction testing equipment mostly adopted a split design, where buoyancy, vibration, penetration devices, and probes were transported separately to the operating area and then assembled underwater. While this design reduced the difficulty of land transportation, the underwater assembly process was cumbersome, and the connections between components were mostly rigidly fixed. Under underwater hydrostatic pressure and wave disturbances, structural stress concentration could easily occur, leading to equipment attitude deviation and affecting test accuracy. With technological advancements, integrated testing systems have emerged, integrating the buoyancy system, penetration system, and vibration system onto a single installation platform. However, existing integrated systems still have significant structural layout defects: the vibration system and penetration system are mostly rigidly fixed without effective vibration isolation structures. When the vibration system simulates wave loads or platform self-vibration, vibration energy can be directly transmitted to the penetration system, causing resonance in the penetration transmission mechanism. This not only affects the penetration stability of the probe but also causes noise interference in the data collected by the pore water pressure sensor, reducing the accuracy of liquefaction potential assessment.

[0005] As a core component for achieving precise probe insertion and retraction, existing penetration systems suffer from numerous design flaws. Traditional systems employ single or dual roller-driven probe structures. Regardless of the roller configuration, the friction driving the probe relies on a multi-power unit drive mechanism or a preload application mechanism. In these designs, multi-power unit drive mechanisms lead to overly complex clamping or pressure bar structures, significantly increasing costs and failure rates. Conventional preload application mechanisms, on the other hand, prevent complete probe release, hindering testing. Furthermore, when long-term testing requires retaining the probe in place, additional auxiliary devices are needed for release. Moreover, existing designs suffer from probe slippage during lifting, resulting in the inability to retrieve the probe and causing significant economic losses. The problem stems from the fact that when the probe is inserted but has not reached the predetermined depth, the lack of an effective torque stabilization mechanism leads to a sudden increase in transmission torque when the soil hardness increases abruptly. This can easily damage transmission components and cause prolonged overload of the penetration system, where the rollers rely on maximum friction to apply penetration force to the probe. Furthermore, changes in the seabed soil during testing alter the probe's resistance, and the upward movement from a stationary state further increases the overall resistance, significantly exceeding the maximum friction force provided by the rollers. Although a vibration system can be used to pull out the probe in practice, the complex stress conditions of the probe in the seabed soil still result in numerous probes becoming stuck and unable to be pulled out.

[0006] In summary, existing seabed sand liquefaction testing systems have significant shortcomings in terms of integrated optimization of structural layout, stability and reliability of the penetration system, adaptability and flexibility of the buoyancy system and installation platform, and synergistic operation of excitation and penetration. These shortcomings result in overall equipment complexity, difficulties in underwater commissioning and probe penetration / lifting, and challenges in ensuring testing efficiency and data accuracy. Consequently, these systems cannot meet the requirements for efficient and accurate in-situ testing of seabed sand liquefaction. Summary of the Invention

[0007] This application addresses the problems existing in the prior art by providing a seabed sand liquefaction testing system with optimized structural layout, stable penetration performance, and efficient collaborative working capabilities, thereby solving the aforementioned problems.

[0008] To achieve the above objectives, the technical solution adopted in this application is as follows: This application provides a seabed sand liquefaction testing system, including an installation platform, a buoyancy system, a vibration system, a probe, and a penetration system; the buoyancy system, the vibration system, the probe, and the penetration system are all installed on the installation platform, and the installation platform is connected to a boat or platform on the sea via cables; The vibration system and the penetration system are stacked together, and the vibration system is connected to the penetration system through a floating connection structure; the penetration system is fixedly connected to the installation platform. The probe passes sequentially through the excitation system and the penetration system; The penetration system includes a penetration power unit, a penetration transmission mechanism, rocker arms, and feed wheels. Two rocker arms are symmetrically arranged in the penetration system, and both rocker arms have a double-headed structure. At least one feed wheel is installed at the end of each rocker arm. The penetration power unit drives the feed wheels to rotate in both directions through the penetration transmission mechanism. Torque retainers are connected in series along the transmission path connecting the two rocker arms in the penetration transmission mechanism, and the outer ring of the torque retainer is fixedly connected to the corresponding rocker arm housing. The penetration transmission mechanism drives the two rocker arms to move in a mirror image through a symmetrically arranged reversing mechanism. After the two rocker arms move to the designated position, the feed wheels on both sides clamp the probe rod; in the clamped state, the feed wheels rotate to drive the probe rod to penetrate or lift.

[0009] Furthermore, the penetration transmission mechanism of the penetration system includes a worm gear transmission pair, a bevel gear transmission pair, and a double-row chain transmission mechanism; The output end of the penetrating power unit is connected to the worm of the worm gear transmission pair; The worm gear of the worm gear transmission pair is connected to the main drive shaft; The main drive shaft is provided with two symmetrical sets of bevel gear transmission pairs, and each set of bevel gear transmission pairs is connected to the corresponding rocker arm. Each set of bevel gear transmission pairs has a driven gear connected to a secondary transmission shaft, and the torque retainer is mounted on the secondary transmission shaft; the secondary transmission shaft is also connected to the drive sprocket of the double-row chain transmission mechanism; Each chain of the double-row chain drive mechanism is distributed along the rocker arm on the corresponding side, and the driven sprockets at both ends of the double-row chain drive mechanism are connected to the feed sprockets.

[0010] Furthermore, the surface of the feed wheel is provided with an annular arc groove, which is adapted to the surface of the probe rod; The feed wheel includes an upper feed wheel and a lower feed wheel; The upper feed wheel is used to drive the probe rod to penetrate; The feed wheel is used to drive the probe rod to lift upward; The surface of the feed wheel is provided with a friction layer, and the surface of the friction layer is machined with tooth-like patterns.

[0011] Furthermore, the penetration system is also provided with a guide sleeve, the inner diameter of which is larger than the outer diameter of the probe. The guide sleeve has a long, narrow groove machined on its side to avoid the feed wheel.

[0012] Furthermore, the excitation system includes an excitation force unit, an excitation transmission mechanism, and an eccentric wheel; The excitation force unit drives the eccentric wheel to rotate through the excitation transmission mechanism.

[0013] Furthermore, in the excitation system, the installation direction of the excitation source is set at an angle to the horizontal direction of the feed wheel clamping direction.

[0014] Furthermore, the probe includes a conical head, a connecting end, and a rod body; the conical head is connected to the rod body via the connecting end. The rod body is a hollow structure with a porous surface and a water pressure gauge installed thereon. The connecting end has a cavity inside; an end resistance sensor is installed in the cavity; and the measuring end of the end resistance sensor is fixed with the conical head.

[0015] Furthermore, the end of the probe is provided with a porous assembly and a pore pressure box; The porous component has internal channels that connect the pore pressure box and the external environment.

[0016] Furthermore, the floating connection structure includes a connecting column and a compression spring; The installation foundation of the excitation system is a box structure, and the box structure is slidably connected to the connecting column; Compression springs are fitted at both ends of the connecting column; one end of the compression spring contacts the box structure, and the other end contacts the mounting platform or the penetration system.

[0017] Furthermore, the buoyancy system is an airbag-type buoyancy adjustment system, including an airbag, a support frame, a protective shell, and a pressure compensation system; The support frame is fixedly connected to the installation platform, and the protective shell is installed on the outside of the support frame; The airbag is installed inside the cavity formed by the support frame and the protective shell; the airbag is inflated and deflated by the pressure compensation system to adjust the buoyancy of the system.

[0018] Compared with the prior art, this application has the following advantages: This application integrates various systems and connects them to the waterborne facilities via cables, optimizing the structural layout for convenient testing. The vibration system and penetration system are stacked and floatingly connected, effectively isolating vibration and preventing resonance in the penetration system and noise in the pore water pressure data caused by vibration energy, thus ensuring the accuracy of liquefaction potential assessment. Furthermore, the symmetrical double-rocker arm, double-head structure of the penetration system, combined with a reversing mechanism, achieves mirror motion. A torque retainer stabilizes the transmission torque, not only achieving constant torque clamping of the rocker arms but also simplifying it into a single power unit, thereby reducing cost and failure rate. The parallel state of the rocker arms allows all feed wheels to leave the probe, solving the problem of difficult probe release, while also enabling the probe to remain in place without additional auxiliary devices. Probe penetration or lifting is achieved through different feed wheels at both ends of the rocker arms, avoiding slippage during lifting and solving retrieval and jamming issues. The overall design significantly improves testing efficiency, reliability, and data accuracy. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the internal structure of the seabed sand liquefaction testing system in a specific embodiment of this application; Figure 2 This is a schematic diagram of the internal structure of the probe of the seabed sand liquefaction testing system in a specific embodiment of this application; Figure 3 This is a top view of the excitation system of the seabed sand liquefaction test system in a specific embodiment of this application; Figure 4 This is a front view of the penetration system of the seabed sand liquefaction testing system in a specific embodiment of this application; Figure 5 This is a rear view of the penetration system of the seabed sand liquefaction testing system in a specific embodiment of this application; Figure 6 This is a front-view perspective view of the penetration system of the seabed sand liquefaction test system in a specific embodiment of this application; Figure 7 This is a rear-view perspective view of the penetration system of the seabed sand liquefaction test system in a specific embodiment of this application; Figure 8 This is a schematic diagram of the worm gear transmission pair and part of the bevel gear transmission pair in a specific embodiment of this application; Figure 9 This is a front perspective view of some bevel gear transmission pairs and double-row chain transmission mechanisms in a specific embodiment of this application; Figure 10This is a rear perspective view of some bevel gear transmission pairs and double-row chain transmission mechanisms in a specific embodiment of this application; Figure 11 This is a schematic diagram of the probe penetration transmission in a specific embodiment of this application; Figure 12 This is a schematic diagram of the probe lifting transmission in a specific embodiment of this application.

[0021] In the diagram: 1. Airbag, 2. Probe, 3. Floating connection structure, 4. Support frame, 5. Protective shell, 6. Vibration system, 7. Penetration system, 8. Mounting platform, 201. Water pressure gauge, 202. Connection end, 203. End resistance sensor, 204. Pore pressure box, 205. Porous assembly, 206. Blind hole, 601. Vibration table, 602. Vibration motor, 603. Main drive gear set, 604. Power shaft, 605. First drive gear set, 606. First eccentric wheel, 607. Second drive gear set, 608. Second eccentric wheel 701. Spindle; 702. Mounting platform; 703. Motor; 704. Worm gear drive pair; 705. Worm; 706. Driving bevel gear; 707. Driven bevel gear; 708. First support; 709. Second support; 7000. First rocker arm; 7001. Torque retainer; 70002. Double row sprocket; 70003. Upper drive chain; 70004. Upper driven sprocket; 70005. Lower drive chain; 70006. Lower driven sprocket; 7001. Second rocker arm; 7002. Feed wheel; 7003. Guide sleeve. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] In the description of this application, it should be understood that the relative relationships indicated by terms such as "upper" and "lower" are based on the positional relationships shown in the accompanying drawings, and are used for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, and therefore should not be construed as a limitation of this application.

[0025] In the description of this application, "multiple" means two or more, unless otherwise expressly and specifically defined.

[0026] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0028] It is worth noting that, unless otherwise specified, the methods used in this application are all conventional methods; and the raw materials and equipment used are all conventional commercially available products, and their sources are not specifically limited.

[0029] This application provides a seabed sand liquefaction testing system, such as... Figures 1-10 As shown, it mainly includes an installation platform, a buoyancy system, a vibration system, a probe, and a penetration system.

[0030] The installation platform 8 adopts a double-layer box structure, with the vibration system 6 installed on the upper layer and the penetration system 7 installed on the lower layer.

[0031] A buoyancy system is also installed on the upper part of the mounting platform 8. In this embodiment, the buoyancy system is an airbag-type buoyancy adjustment system, including an airbag 1, a support frame 4, a protective shell 5, and a pressure compensation system. The support frame 4 is a stainless steel cage structure, fixedly connected to the mounting platform 8 at its bottom. It has a multi-lobed independent structure along its circumference, with each lobe covered by a non-metallic protective shell 5 and an independent airbag 1 disposed on its inner side. The protective shell 5 protects the internal airbag 1. The pressure compensation system is connected to each airbag 1. When the airbag 1 deflates, the overall buoyancy decreases, and the test system sinks; when the airbag is filled with compressed air, it expands and releases water to increase the overall buoyancy, and the test system floats. Multiple lifting rings are fixed to the top surface of the support frame 4 for connecting cables, allowing the test system of this embodiment to be hoisted or retrieved using the lifting equipment of a boat or platform.

[0032] The mounting platform 8 has a through hole running vertically for mounting the probe rod 2, which passes sequentially through the vibration system 6 and the penetration system 7. In this embodiment, the probe rod 2 includes a conical head, a connecting end, and a rod body. The rod body employs a multi-section coaxial connection design and is hollow to house the sensor's data cable. The surface of the rod body is machined with a porous structure, and a water pressure gauge 201 is installed in the holes to measure pore water pressure. The conical head is connected to the rod body via the connecting end 202. The connecting end 202 is a hollow cylindrical structure, coaxially connected to the rod body. The connecting end 202 has a stepped structure inside, forming a front cavity in which an end resistance sensor 203 is installed. The measuring end of the end resistance sensor 203 is fixed with the conical head. Furthermore, a porous assembly 205 is provided between the measuring end of the end resistance sensor 203 and the conical head. Specifically, multiple radially distributed channels are machined on the conical head, with a vertical channel at the center. The multiple radially distributed channels are connected to one side of the end resistance sensor 203 through the central channel. A blind hole 206 is machined on the measuring end of the end resistance sensor 203, and a pore pressure box 204 is installed at the bottom of the blind hole 206. The pore pressure box 204 is connected to the external environment through the channels and holes on the porous assembly 205.

[0033] The excitation system 6 and the penetration system 7 are stacked, and the excitation system 6 is connected to the penetration system 7 via a floating connection structure 3. Specifically, the installation foundation of the excitation system 6 is the upper box structure in the installation platform 8, with through holes machined at its four corners. The floating connection structure 3 includes connecting columns and compression springs; the box structure of the excitation system 6 is slidably connected to the connecting columns. Each connecting column has compression springs fitted at both ends; one end of the upper compression spring contacts the box structure, and the other end contacts the top plate of the installation platform 8; one end of the lower compression spring contacts the box structure of the excitation system 6, and the other end contacts the box structure of the penetration system 7. In this embodiment, through the vibration isolation design of the floating connection structure 3, the excitation effect generated by the excitation system 6 can be prevented from directly affecting the penetration system 7, and can only be indirectly affected through the vibration of the probe 2, thus reducing the occurrence of system resonance.

[0034] Furthermore, the excitation system 6 in this embodiment includes an excitation table 601, an excitation power unit, an excitation transmission mechanism, and an eccentric wheel. The excitation power unit drives the eccentric wheel to rotate through the excitation transmission mechanism. Specifically, the excitation table 601 has a through hole running vertically through it for the probe 2 to pass through. The excitation power unit uses an excitation motor 602, whose output shaft is connected to the excitation transmission mechanism. The excitation transmission mechanism includes a main transmission gear set 603, a first transmission gear set 605, and a second transmission gear set 607. The driving gear of the main transmission gear set 603 is connected to the excitation motor 602, and the driven gear is connected to the power shaft 604. The two ends of the power shaft 604 are respectively connected to the first transmission gear set 605 and the second transmission gear set 607, and the first transmission gear set 605 and the second transmission gear set 607 drive the first eccentric wheel 606 and the second eccentric wheel 608, respectively. Preferably, to avoid the vibration system 6 affecting the clamping state of the probe 2, the vibration source in the vibration system is installed at an angle to the horizontal direction and the clamping direction of the feed wheel. One method is as follows: Figure 3 As shown, the projection direction of the eccentric wheel rotation plane on the horizontal plane is set at a 45° angle with the projection direction of the feed wheel rotation plane in the penetration system 7. This can reduce the impact of vibration on the clamping state of the probe rod 2.

[0035] In this embodiment, a sleeve is installed at the through hole of the excitation table 601. The sleeve slides with the probe rod 2, thereby realizing the excitation effect of the excitation system 6 on the probe rod 2. Specifically, the excitation effect of the excitation system follows the path of excitation force generation - probe rod transmission - sand layer response, and finally acts on sand layers at different depths on the seabed. By inducing the vibration response of the sand and the change of pore water pressure, it provides load conditions that conform to the actual engineering scenario for the in-situ test of seabed sand liquefaction.

[0036] The penetration system 7 is fixedly connected to the mounting platform 8 and is located in the lower box structure. The penetration system 7 is equipped with a penetration power unit, a penetration transmission mechanism, a rocker arm, and a feed wheel.

[0037] The penetration system comprises two symmetrically arranged rocker arms, namely the first rocker arm 706 and the second rocker arm 707, both of which are double-headed structures. The penetration system 7 is mounted as a whole on a plate-shaped mounting platform 701, and the two rocker arms are rotatably connected to the split-design first support 704 and the second support 705, respectively. Each rocker arm has a feed wheel 708 rotatably mounted at both ends. Thus, when the rocker arm swings, it can drive the feed wheel 708 to swing. The split design of the first support 704 and the second support 705 in this embodiment allows for angle adjustment when the rocker arm clamps the probe 2. That is, the mounting holes of the supports are designed as elongated holes and are fixed to the mounting platform 701 with bolts. When it is necessary to adjust the angle of the rocker arm clamping the probe 2, it can be achieved by adjusting the distance between the two supports (which requires corresponding adjustment of the position of the penetration power unit and the penetration transmission mechanism), thereby changing the clamping force.

[0038] Furthermore, in this embodiment, the penetration power unit is an electric motor 702, which drives the feed wheel 708 to rotate in both directions through a penetration transmission mechanism. Specifically, the penetration transmission mechanism includes a worm gear transmission pair 703, a bevel gear transmission pair, and a double-row chain transmission mechanism. The output shaft of the electric motor 702 is coaxially connected to the worm 7031 via a coupling, and the worm gear 7032 is coaxially fixed to the main drive shaft. The main drive shaft passes through the first support 704 and the second support 705, and the driving bevel gear 7033 and the driven bevel gear 7034 of the bevel gear transmission pair are installed in the corresponding supports. The two sets of driving bevel gears 7033 and driven bevel gears 7034 are symmetrically arranged, thereby realizing the mirror motion of the driving components.

[0039] Driven bevel gear 7034 drives rocker arm and feed wheel 708 to rotate. Specifically, refer to... Figure 9 and Figure 10 As shown, this embodiment uses the first rocker arm 706 as a specific example for transmission. A torque retainer 7061 is mounted on the output shaft of the driven bevel gear 7034. Taking the common torque retainer 7061 as an example, it has a three-layer structure, namely an inner ring, a friction layer and an outer ring. The inner ring is connected to the output shaft of the driven bevel gear 7034 by a key connection, while the outer ring is fixedly connected to the housing of the rocker arm. By sealing and waterproofing the torque retainer 7061, constant torque operation can be performed on the seabed: when the rocker arm swings and the feed wheel does not contact the probe 2, since the resistance on the rocker arm is less than the torque set by the torque retainer 7061, the driven bevel gear 7034 can drive the rocker arm to swing forward and backward; when the feed wheel 708 on one side of the rocker arm contacts the probe 2, the rocker arm can no longer swing, and the driven bevel gear 7034 continues to rotate, causing the torque on the torque retainer 7061 to rise to the set value, and then the friction layer begins to slip, thereby maintaining the subsequent torque constant at the set value, thus applying a stable clamping force to the probe 2. The output shaft of the driven bevel gear 7034 is connected to the driving sprocket of the double-row chain drive mechanism. Specifically, the driving sprocket is a double-row sprocket 7062, and the output shaft of the driven bevel gear 7034 is fixedly connected to the double-row sprocket 7062. The double-row sprocket 7062 drives two chains distributed along both ends of the rocker arm, namely the upper drive chain 7063 and the lower drive chain 7065. The two chains are connected to the upper driven sprocket 7064 and the lower driven sprocket 7066 at their ends, respectively, and the two driven sprockets are coaxially fixed to the corresponding feed wheel 708.

[0040] Combination Figure 11 and Figure 12 As shown, the working principle of the penetration system 7 is as follows: Penetration: such as Figure 11As shown, the electric motor 702 drives the main drive shaft to rotate in the forward direction, which in turn drives the bevel gear transmission pair to drive the upper part of the two rocker arms to swing inward and close together. After clamping the probe rod 2, due to the sharp increase in torque, the torque retainer 7061 begins to slip at the constant torque, thereby applying a stable clamping force to the probe rod 2 by the two upper feed wheels. As the driven bevel gear continues to rotate, it drives the two upper feed wheels to continue rotating through the upper transmission chain of the two rocker arms, and then drives the probe rod 2 downward into the seabed by the friction force generated by the clamping force. Release: When probe 2 penetrates to the predetermined depth, motor 702 reverses by a preset number of revolutions, causing the two rocker arms to swing back to the vertical position. At this time, either feed wheel disengages from probe 2, and motor 702 stops rotating, completing the release of probe 2. Upward: such as Figure 12 As shown, the motor 702 reverses to drive the main drive shaft to rotate, which in turn drives the bevel gear transmission pair to drive, causing the lower parts of the two rocker arms to swing inward and close together. After clamping the probe 2, due to the sharp increase in torque, the torque retainer 7061 begins to slip at a constant torque, thereby applying a stable clamping force to the probe 2 by the two lower feed wheels. As the driven bevel gear continues to rotate, it drives the two lower feed wheels to continue rotating through the lower transmission chains of the two rocker arms, and then drives the probe 2 to be lifted upward from the seabed by the friction force generated by the clamping force.

[0041] It should be noted that during the above operation, since this embodiment adopts a double-row chain transmission mechanism, the four feed wheels 708 rotate with the motor 702. Due to the different clamping postures of the rocker arm, the unrelated feed wheels 708 do not participate in the operation and do not affect the penetration / lifting operation.

[0042] The above design simplifies the penetration system 7 into a single power unit, which not only reduces costs but also enables the three required actions and constant torque clamping without the need for complex auxiliary equipment. Furthermore, since different sets of feed wheels 708 are used for penetration or lifting operations, different forces can be applied to the probe rod 2 according to the requirements, thereby reducing the occurrence of probe rod 2 getting stuck and unable to be retrieved. A preferred design is as follows: the feed wheel 708 has an annular arc groove on its surface, which is adapted to the surface of the probe rod 2 so that its inner side fits against the circumference of the probe rod 2 when in the clamping state. As mentioned above, the feed wheel 708 is divided into an upper feed wheel and a lower feed wheel. The upper feed wheel is used to drive the probe rod 2 to penetrate, and the lower feed wheel is used to drive the probe rod 2 to lift. In order to achieve different frictional forces under the same clamping force, a friction layer is provided on the surface of the lower feed wheel, and toothed patterns are machined on the surface of the friction layer, thereby increasing the maximum frictional force of the lower feed wheel. Another preferred design is that the lengths of the two ends of the first rocker arm 706 and the second rocker arm 707 are different, that is, the length of the upper rocker arm (the wheelbase between the upper driven sprocket 7064 and the double row sprocket 7062) is greater than the length of the lower rocker arm (the wheelbase between the lower driven sprocket 7066 and the double row sprocket 7062). In this way, because the clamping angles are different, under the same torque conditions, the clamping force applied by the lower feed wheel to the probe 2 during the lifting process is greater than the clamping force applied by the upper feed wheel to the probe 2 during the penetration process, thereby making the friction force during the penetration period less than the friction force during the lifting period.

[0043] Optionally, the penetration system 7 also includes a guide sleeve 709, which is a hollow cylindrical structure. Its lower end is bolted to the mounting platform 701 via a connecting flange. A through hole is machined at a corresponding position on the mounting platform 701 for the probe 2 to pass through, and the guide sleeve 709 is coaxially arranged with the through hole to guide the probe 2. The inner diameter of the guide sleeve 709 is larger than the outer diameter of the probe 2, and a long slot is machined on the side of the guide sleeve 709 to avoid the feed wheel 708.

[0044] Work process: Preparation: First, collect ocean tide data, select the slack tide period when the water surface is stable and basically still between high tide and low tide to carry out static cone penetration, and at the same time understand the wind force, wave level and visibility conditions; then use a ship to transport the equipment to the designated sea area, assemble the various components of the test system of this embodiment into a whole on the ship, and check the sealing of the device. Positioning: The system is towed to the sea surface above the test site, the buoyancy system is activated, and the system is slowly sank to the seabed. After reaching the seabed, the operator uses the underwater positioning system to park it at the designated test location based on the feedback information. Orifice elevation determination: After overall positioning, the orifice elevation is obtained using data from the underwater acoustic positioning system, and compared and corrected with the tide table to determine the seabed elevation; Static cone penetration test and alarm: Turn on the static cone penetration test system, put the penetration system in place, carry out static cone penetration and collect pore water pressure data; if an abnormal situation is encountered during the operation of the cone probe or the soil layer is hard and difficult to penetrate, an alarm will be set off automatically. At this time, the operation must be stopped immediately to prevent the cone probe from being damaged. Determination of liquefaction potential of seabed soil: Close the cone penetration feed system, remove the feed wheel from the probe rod, observe the pore water pressure changes at each pore water pressure gauge, and after the pore water pressure stabilizes (i.e. reaches the static pore water pressure), start the excitation system, observe and record the pore water pressure changes, and judge the liquefaction potential of sand at different depths to evaluate the liquefaction of the site. Instrument and equipment recovery: After the test, if long-term observation is required, probe 2 can be released and the buoyancy system can be activated to recover the equipment; if long-term observation is not required, probe 2 can be raised while vibrating, probe 2 can be recovered, the buoyancy system can be activated to recover the equipment, and then you can go to other test points to continue working. All of the above work processes are monitored in real time by the operating platform on the ship via data cables.

[0045] Finally, it should be noted that the above content is only used to illustrate the technical solution of this application, and is not intended to limit the scope of protection of this application. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of this application shall not depart from the substance and scope of the technical solution of this application.

Claims

1. A seabed sand liquefaction testing system, characterized in that, It includes an installation platform, a buoyancy system, a vibration system, a probe, and a penetration system; the buoyancy system, the vibration system, the probe, and the penetration system are all installed on the installation platform, which is connected to a boat or platform via cables; The vibration system and the penetration system are stacked together, and the vibration system is connected to the penetration system through a floating connection structure; the penetration system is fixedly connected to the installation platform. The probe passes sequentially through the excitation system and the penetration system; The penetration system includes a penetration power unit, a penetration transmission mechanism, rocker arms, and feed wheels. Two rocker arms are symmetrically arranged in the penetration system, and both rocker arms have a double-headed structure. At least one feed wheel is installed at the end of each rocker arm. The penetration power unit drives the feed wheels to rotate in both directions through the penetration transmission mechanism. Torque retainers are connected in series along the transmission path connecting the two rocker arms in the penetration transmission mechanism, and the outer ring of the torque retainer is fixedly connected to the corresponding rocker arm housing. The penetration transmission mechanism drives the two rocker arms to move in a mirror image through a symmetrically arranged reversing mechanism. After the two rocker arms move to the designated position, the feed wheels on both sides clamp the probe rod; in the clamped state, the feed wheels rotate to drive the probe rod to penetrate or lift.

2. The seabed sand liquefaction testing system according to claim 1, characterized in that, The penetration transmission mechanism of the penetration system includes a worm gear transmission pair, a bevel gear transmission pair, and a double-row chain transmission mechanism. The output end of the penetrating power unit is connected to the worm of the worm gear transmission pair; The worm gear of the worm gear transmission pair is connected to the main drive shaft; The main drive shaft is provided with two symmetrical sets of bevel gear transmission pairs, and each set of bevel gear transmission pairs is connected to the corresponding rocker arm. Each set of bevel gear transmission pairs has a driven gear connected to a secondary transmission shaft, and the torque retainer is mounted on the secondary transmission shaft; the secondary transmission shaft is also connected to the drive sprocket of the double-row chain transmission mechanism; Each chain of the double-row chain drive mechanism is distributed along the rocker arm on the corresponding side, and the driven sprockets at both ends of the double-row chain drive mechanism are connected to the feed sprockets.

3. The seabed sand liquefaction testing system according to claim 1, characterized in that, The feed wheel has an annular arc groove on its surface, and the arc groove is adapted to the surface of the probe rod; The feed wheel includes an upper feed wheel and a lower feed wheel; The upper feed wheel is used to drive the probe rod to penetrate; The feed wheel is used to drive the probe rod to lift upward; The surface of the feed wheel is provided with a friction layer, and the surface of the friction layer is machined with tooth-like patterns.

4. The seabed sand liquefaction testing system according to claim 1, characterized in that, The penetration system is also provided with a guide sleeve, the inner diameter of which is larger than the outer diameter of the probe. The guide sleeve has a long, narrow groove machined on its side to avoid the feed wheel.

5. The seabed sand liquefaction testing system according to claim 1, characterized in that, The excitation system includes an excitation force unit, an excitation transmission mechanism, and an eccentric wheel; The excitation force unit drives the eccentric wheel to rotate through the excitation transmission mechanism.

6. The seabed sand liquefaction testing system according to claim 1, characterized in that, In the excitation system, the installation direction of the excitation source is set at an angle to the horizontal direction and the clamping direction of the feed wheel.

7. The seabed sand liquefaction testing system according to claim 1, characterized in that, The probe includes a conical head, a connecting end, and a rod body; the conical head is connected to the rod body via the connecting end. The rod body is a hollow structure with a porous surface and a water pressure gauge installed thereon. The connecting end has a cavity inside; an end resistance sensor is installed in the cavity; and the measuring end of the end resistance sensor is fixed with the conical head.

8. The seabed sand liquefaction testing system according to claim 1, characterized in that, The probe is equipped with a porous assembly and a pore pressure box at its end; The porous component has internal channels that connect the pore pressure box and the external environment.

9. The seabed sand liquefaction testing system according to claim 1, characterized in that, The floating connection structure includes a connecting column and a compression spring; The installation foundation of the excitation system is a box structure, and the box structure is slidably connected to the connecting column; Compression springs are fitted at both ends of the connecting column; one end of the compression spring contacts the box structure, and the other end contacts the mounting platform or the penetration system.

10. The seabed sand liquefaction testing system according to claim 1, characterized in that, The buoyancy system is an airbag-type buoyancy adjustment system, including an airbag, a support frame, a protective shell, and a pressure compensation system; The support frame is fixedly connected to the installation platform, and the protective shell is installed on the outside of the support frame; The airbag is installed inside the cavity formed by the support frame and the protective shell; the airbag is inflated and deflated by the pressure compensation system to adjust the buoyancy of the system.

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