Testing device and method for researching horizontal load of suction barrel under high compactness of sandy soil

Abstract

The invention relates to a test device and method for researching horizontal load of a suction bucket under high compactness of sandy soil. The device comprises a model box, a suction bucket model system, a suction bucket mounting and up-pulling system and a horizontal loading and measuring system. A high-compactness sandy soil sample is prepared and contained in the model box. The suction bucket model system simplifies sensor arrangement and reduces penetration resistance. And the suction bucket mounting and upward pulling system realizes mounting and pulling of the suction bucket by utilizing a hydraulic oil cylinder and a lifting cross beam. The horizontal loading and measuring system applies static force and dynamic load through a pulley, a steel wire rope, a servo motor and a balancing weight to form sinusoidal waveform bending moment, simulates the real stress condition and measures the horizontal displacement and inclination angle change of the suction barrel. According to the device, a loading system is optimized, the reliability and precision of test data are improved, the cost is reduced, and the device is suitable for safety and stability research of an ocean engineering structure.

Description

Technical Field

[0001] The invention relates to the technical field of marine structural engineering, and in particular to a test device and method for studying horizontal load of a suction bucket under high density of sand. Background Art

[0002] With the rapid development of the offshore wind power industry, the suction bucket foundation has gradually become one of the important foundation types in marine structural engineering due to its simple construction, low cost and environmental friendliness, and has been widely used in the construction of offshore wind farms. Among them, the study of the horizontal bearing capacity of the suction bucket foundation is an important link to ensure its safety and stability in the marine environment. The geological conditions in the marine environment are complex and changeable, including different types of sediments such as sand, silt, and clay. The mechanical properties of these sediments under high-density conditions directly affect the bearing capacity and deformation behavior of the suction bucket foundation. Therefore, in-depth research on the horizontal load-bearing performance of the suction bucket under high-density sand conditions is of great engineering significance for optimizing the design of the suction bucket foundation, improving its ability to resist horizontal loads, and ensuring the long-term stability of the structure.

[0003] However, there are many problems in the current test process of suction buckets, including the following aspects:

[0004] The cyclic loading method of precision servo motors is expensive and has insufficient torque: In horizontal bearing capacity tests, servo motors are often used, but precision servo motors are expensive and have insufficient torque, which is difficult to meet actual needs. The use of precision servo motors not only increases the test cost, but also may not provide sufficient torque under high load conditions, limiting the scope and depth of the test.

[0005] The suction bucket itself has a complex sensor setup: During the test, the sensor setup still has multiple wiring lines that interfere with the test accuracy. Multiple sensor lines not only increase the complexity of the test layout, but are also easily interfered with by the environment and equipment, affecting the accuracy and stability of the data. In addition, when the sensors are arranged on the bucket, due to the uneven shape, they will affect the penetration resistance and bearing capacity of the suction bucket.

[0006] It should be noted that the information disclosed in the above background technology section is only used for understanding the background of the present application, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the invention

[0007] The main purpose of the present invention is to overcome the defects existing in the above-mentioned background technology and to provide a test device and method for studying the horizontal load of a suction bucket under high density of sand.

[0008] To achieve the above object, the present invention adopts the following technical solutions:

[0009] A test device for studying the horizontal load of a suction bucket under high density of sand, comprising:

[0010] Model box for preparing and containing high-density sand samples;

[0011] Suction bucket model system, used to simulate the installation and loading state of suction bucket foundation in sand;

[0012] Suction bucket installation and pull-up system, used to control the vertical installation and pull-out operation of the suction bucket model system;

[0013] Horizontal loading and measuring system, used to apply horizontal static and dynamic loads to the suction bucket model system, including:

[0014] Pulley, used to change the force direction of the loading wire rope;

[0015] Steel wire ropes connect the counterweights and the swingable crossbar to transmit the loading force;

[0016] Servo motor controls the reciprocating motion of the swingable crossbar to achieve dynamic moment loading;

[0017] The counterweights, including fixed counterweights and adjustable counterweights, work in conjunction with the servo motors to form sinusoidal bending moment loading with specific amplitude and frequency to simulate actual stress conditions by changing their positions and masses;

[0018] Among them, static loading is formed by the counterweight block, and dynamic loading is formed by driving the counterweight block through the servo motor to generate dynamic bending, and the horizontal displacement of the suction bucket during the loading process and the inclination change of the rotation center of the suction bucket are measured.

[0019] Furthermore, gravel, geotextile and sand are arranged in sequence from bottom to top in the model box, and is equipped with inlet and outlet valves to achieve the saturation and drainage process of the sand.

[0020] Furthermore, the suction bucket model system comprises:

[0021] Suction bucket foundation is made of bottomless and covered steel, with two symmetrical drainage holes on the cover for drainage during installation;

[0022] The barrel wall sensor installation device surrounds the barrel of the barrel foundation and is equipped with an earth pressure sensor to monitor the load state of the suction barrel foundation in the sand.

[0023] Furthermore, the barrel wall sensor installation device includes:

[0024] Aluminum plates, symmetrically arranged at both ends of the barrel wall, are used to install earth pressure sensors;

[0025] The fixing holes and routing grooves on the aluminum plate are used to fix the aluminum plate to the barrel wall and guide the sensor line;

[0026] The holes on the aluminum plate are used to install the earth pressure sensor to measure the pressure of the soil on the barrel wall;

[0027] Preferably, the total thickness of the aluminum plate is more than 5 mm greater than the thickness of the soil pressure sensor, the length of the aluminum plate is slightly smaller than the height of the bucket foundation, the spacing between the holes on the plate is designed to be smaller than the value obtained by dividing the height of the bucket foundation by the number of sensors, and greater than three times the diameter of the sensor, the distance from the hole to the top and bottom of the aluminum plate is greater than twice the diameter of the sensor, and the hole size is slightly larger than the sensor diameter.

[0028] Preferably, it also includes a drag-reducing cutting groove located at the lower end of the aluminum plate to reduce the resistance when the suction bucket penetrates.

[0029] Furthermore, the suction bucket installation and pulling-up system comprises:

[0030] A lifting beam is used to support the extension screw and control the vertical movement of the suction bucket;

[0031] The wire displacement sensor is installed on the lifting beam and extends to the top beam of the model box to monitor the lifting height of the suction bucket in real time;

[0032] The extended screw rod passes through the center hole of the lifting beam and is connected to the vertical screw rod to transmit the lifting force to the suction bucket;

[0033] The hydraulic cylinder has its bottom fixed to the top beam of the model box and its top connected to the lifting beam, and the vertical movement of the lifting beam is achieved through oil pressure drive;

[0034] The lower end of the vertical screw is connected to the extended screw, and the upper end is connected to the suction bucket. The displacement sensor is installed at the upper and lower positions of the vertical screw, and the inclination sensor is fixed on the vertical screw.

[0035] Furthermore, the horizontal loading and measuring system specifically comprises:

[0036] Loading pulley, installed on the upper and lower brackets of the model box, used to guide the wire rope and change the direction of the force;

[0037] The loading wire rope connects the horizontal load pull ring, the counterweight block and the swingable cross bar to transfer the horizontal load to the suction bucket;

[0038] The horizontal load pull ring is fixed on the vertical screw and serves as the connection point of the wire rope to ensure accurate transfer of the load;

[0039] The servo motor controls the reciprocating swing of the swingable crossbar to achieve precise loading of dynamic bending moment;

[0040] The counterweights, including an adjustable counterweight connected to the swingable crossbar and a fixed counterweight for the balancing system, cooperate with the servo motor to form a sinusoidal bending moment loading with a specific amplitude and frequency;

[0041] The swingable crossbar connects the servo motor and the counterweight, converting the rotary motion of the servo motor into the reciprocating linear motion of the counterweight to achieve dynamic loading;

[0042] The model box top bracket and the model box bottom bracket are used to install the pulley and fix the entire horizontal loading system.

[0043] A method for studying the horizontal load of a suction bucket under high density of sand using the test device comprises the following steps:

[0044] S1. Prepare sand sample: fill the model box with sand to create a high-density sand environment;

[0045] S2. Suction bucket installation: Install the bucket wall sensor and use the hydraulic system to press the suction bucket into the sand to a predetermined depth;

[0046] S3, horizontal loading: static load is applied through steel wire rope and counterweight, displacement sensor and inclination sensor are used to monitor displacement and rotation of suction bucket, and counterweight is gradually added until the system is destroyed; servo motor is used to control the swingable cross bar and counterweight to swing back and forth, forming dynamic bending moment loading, realizing sinusoidal waveform loading, and displacement sensor and inclination sensor are continuously used to monitor displacement and rotation of suction bucket;

[0047] S4. Pulling up the suction bucket: After loading is completed, operate the hydraulic system to pull the suction bucket out of the sand.

[0048] Further, in step S1, gravel, geotextile and saturated sand are laid in the model box in sequence;

[0049] In step S2, before installing the suction bucket, the bucket wall sensor installation device is first installed at a predetermined position, and then the lifting beam is controlled by the hydraulic cylinder, and the suction bucket is pressed into the sand to the target depth by using the extended screw, and the pull-wire displacement sensor monitors the installation depth of the suction bucket in real time;

[0050] In step S3, the vertical screw is connected to the counterweight by a horizontal load pull ring and a steel wire rope to form a static loading system. During the static loading process, the displacement and rotation of the suction bucket are monitored by a displacement sensor and an inclination sensor, and the counterweight is gradually added until the system is destroyed. During the dynamic loading process, the counterweight is controlled to swing back and forth by a servo motor to form a dynamic bending moment loading, realize sinusoidal waveform loading, and continuously use the displacement sensor and inclination sensor to monitor the displacement and rotation of the suction bucket.

[0051] In step S4, after the suction bucket is destroyed, the lifting function of the hydraulic cylinder is used to lift the lifting beam and the extension screw to separate the suction bucket from the soil and complete the pulling-up operation.

[0052] Furthermore, in step S3, static loading specifically includes:

[0053] Initially load the counterweight to establish the load system, and use the displacement sensor and inclination sensor to monitor the displacement and inclination of the suction bucket;

[0054] When the monitored displacement and inclination are stable within the specified time, the mass of the counterweight is gradually increased until signs of structural damage appear. The signs of structural damage include any of the following situations: the inclination offset exceeds a predetermined threshold, such as exceeding 5°; the sensor reaches the limit length; or the vertical screw is laterally offset.

[0055] Furthermore, in step S3, power loading specifically includes:

[0056] The servo motor is used to control the reciprocating swing of the counterweight to generate a dynamic bending moment waveform with a specific amplitude and frequency;

[0057] By adjusting the mass of the counterweight, the average value and amplitude of the bending moment can be accurately controlled to form a sinusoidal waveform loading;

[0058] During the entire dynamic loading process, displacement sensors and inclination sensors are continuously used to monitor the displacement and inclination of the suction bucket to ensure the accuracy of loading and the stability of the system.

[0059] The present invention has the following beneficial effects:

[0060] The present invention proposes a test device and method for studying the horizontal load of a suction bucket under high density of sand. The horizontal loading system designed in the device not only solves the problem of insufficient torque of traditional servo motors, but also can apply periodic cyclic loads under high load conditions. The modular design simplifies the sensor layout, optimizes the loading system, reduces line redundancy and data interference, and improves the economy of the test and the reliability of the data.

[0061] Compared with the prior art, the advantages of the present invention mainly include:

[0062] 1. The horizontal loading system of the present invention adopts a configuration block loading method and overcomes the problem of insufficient torque of traditional servo motors through reasonable counterweight block design. It can still provide sufficient loading capacity and periodic cyclic load application under high load conditions, expand the test range, and is suitable for more complex load tests.

[0063] 2. By optimizing the sensor layout and sensor line design, the present invention effectively avoids the problem of excessive sensor routing and interference with data accuracy in traditional tests. In particular, the barrel wall sensor installation device reduces resistance interference during the penetration process and ensures high-precision collection of test data. This innovation significantly improves the reliability of test results and reduces errors caused by external environmental interference.

[0064] Compared with the traditional system, the device of the present invention is more cost-effective, can better simulate the actual stress state of the suction bucket foundation in high-density sand, provide accurate horizontal load data, and provide a scientific basis for the optimal design of the suction bucket foundation.

[0065] Other beneficial effects of the embodiments of the present invention will be further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 Schematic diagram of a horizontal loading system according to an embodiment of the present invention.

[0067] Figure 2 This is a wall sensor installation device according to an embodiment of the present invention.

[0068] Figure 3 This is the displacement load curve of the embodiment of the present invention when the suction cylinder has a height of 240 mm and an operating height of 180 mm.

[0069] In the figure: model box 1, operating table 2, gravel 3, geotextile 4, sand 5, inlet and outlet valve 6, suction bucket drainage hole 7, soil pressure sensor 8, soil pressure sensor 9, soil pressure sensor 10, soil pressure sensor 11, soil pressure sensor 12, soil pressure sensor 13, soil pressure sensor 14, soil pressure sensor 15, lifting beam 16, wire displacement sensor 17, extension screw 18, hydraulic cylinder 19, top beam 20 of model box, vertical screw 21, counterweight 22 (m1), counterweight 23 (m2), counterweight 24 (m3), servo motor 25, loading wire rope 26, top bracket of model box 27, lower bracket of model box 28, swingable cross bar 29, loading pulley 30, hole 31, threading hole 32, fixing hole 33, wiring groove 34, cutting 35, horizontal load pull ring 36, LVDT displacement sensor 37, inclination sensor 38. DETAILED DESCRIPTION

[0070] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope and application of the present invention.

[0071] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for fixing as well as for coupling or communication.

[0072] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0073] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0074] See also Figures 1 to 3 An embodiment of the present invention provides a test device for studying the horizontal load of a suction bucket under high density of sand, including a model box, a suction bucket model system, a suction bucket installation and pulling system, and a horizontal loading and measurement system.

[0075] The model box is used to prepare and contain high-density sand samples.

[0076] The suction bucket model system is used to simulate the installation and loading state of the suction bucket foundation in sand.

[0077] The suction bucket installation and extraction system is used to control the vertical installation and extraction operations of the suction bucket model system.

[0078] The horizontal loading and measurement system is used to apply horizontal static and dynamic loads to the suction bucket model system, including: a pulley, used to change the force direction of the loading wire rope; a wire rope, connecting each counterweight block and the swingable cross bar to transmit the loading force; a servo motor, controlling the reciprocating motion of the swingable cross bar to achieve dynamic bending moment loading; counterweight blocks, including fixed counterweight blocks and adjustable counterweight blocks, which work in conjunction with the servo motor by changing their position and mass to form a sinusoidal waveform bending moment loading with a specific amplitude and frequency to simulate actual stress conditions; wherein, static loading is formed by the counterweight block, and dynamic loading is formed by driving the counterweight block to generate dynamic bending through the servo motor, and the horizontal displacement of the suction bucket during the loading process and the change in the inclination angle of the suction bucket's rotation center are measured.

[0079] The embodiment of the present invention also provides a method for studying the horizontal load of a suction bucket under high density of sand using the test device, comprising the following steps:

[0080] Step S1, preparing a sand sample: filling a model box with sand to create a high-density sand environment;

[0081] Step S2, suction bucket installation: installing a bucket wall sensor and using a hydraulic system to press the suction bucket into the sand to a predetermined depth;

[0082] Step S3, horizontal loading: static load is applied through steel wire rope and counterweight, displacement sensor and inclination sensor are used to monitor displacement and rotation of suction bucket, and counterweight is gradually added until the system is destroyed; servo motor is used to control the swingable cross bar and counterweight to swing back and forth, forming dynamic bending moment loading, realizing sinusoidal waveform loading, and displacement sensor and inclination sensor are continuously used to monitor displacement and rotation of suction bucket;

[0083] Step S4, pulling up the suction bucket: after loading is completed, operating the hydraulic system to pull the suction bucket out of the sand.

[0084] The test device and method of the present invention provide a cost-effective and data-reliable testing solution for the safety and stability requirements of the suction bucket foundation in the construction of offshore wind farms. The horizontal loading system adopts an innovative combination of pulleys, wire ropes, servo motors and counterweights, which not only solves the problem of insufficient torque of traditional servo motors, but also can apply periodic cyclic loads under high load conditions, so that the test range can be expanded and suitable for more complex load conditions. In addition, the device optimizes the sensor layout and line design, reduces wiring redundancy and external interference, and improves the accuracy of data acquisition. The present invention not only significantly improves the reliability of the test results, but also reduces the errors caused by external environmental interference, provides a scientific basis for the optimal design of the suction bucket foundation, and ensures the long-term stability of the structure.

[0085] The specific embodiments of the present invention are further described below.

[0086] A test device and method for studying the horizontal load of a suction bucket under high-density sand. The device includes a model box, a suction bucket model system, a suction bucket installation and pull-up system, and a horizontal loading system. The model box is used to prepare high-density sand samples, and the suction bucket model system reduces penetration resistance and improves test accuracy by simplifying the sensor arrangement. The suction bucket installation and pull-up system uses a hydraulic cylinder, a lifting beam, and an extended screw to ensure that the suction bucket is smoothly installed and pulled out at a predetermined depth. The horizontal loading system implements horizontal load testing through pulleys, wire ropes, servo motors, and counterweights, applies dynamic bending moments, and simulates the actual stress conditions in high-density sand. The present invention optimizes the loading system and sensor arrangement, reduces costs, and improves the reliability and accuracy of test data, and can better simulate the stress behavior of the suction bucket foundation in high-density sand.

[0087] A test device for studying the horizontal load of a suction bucket under high density of sandy soil comprises a model box 1, a suction bucket model system, a suction bucket horizontal loading and measuring system, and a suction bucket installation and pulling-up system.

[0088] The model box 1 is located on an operating table 2, and the model box 1 contains gravel 3, geotextile 4, and sand 5 from bottom to top. Inlet and outlet valves 6 are also provided for drainage and saturation.

[0089] The suction bucket model system comprises a suction bucket foundation and a bucket wall sensor installation device.

[0090] The suction bucket foundation is made of bottomless steel with a cover. Two symmetrical holes are opened on the cover plate surface of the suction bucket foundation from the central circle as suction bucket drainage holes 7 for drainage during installation of the bucket foundation. A barrel wall sensor installation device is installed around the barrel of the barrel foundation.

[0091] The barrel wall sensor mounting device is made of aluminum plate. Figure 2As shown. They are symmetrically arranged at both ends of the barrel wall for placing soil pressure sensors 8-15. The total thickness T2 of the aluminum plate is more than 5 mm greater than the thickness of the soil pressure sensor to be arranged, and the plate length L2 is slightly less than the barrel foundation height H. The spacing of the holes 31 on the plate is determined according to the number of sensors n, the distance between the holes 31 is set less than H / n, and the spacing between the holes 31 is slightly greater than 3D. The holes 31 arranged at both ends are greater than 2D from the top and bottom of the plate, and the size of the holes 31 is slightly larger than the sensor diameter D to avoid mutual influence. A fixing hole 33 is opened at a distance of 1D from the top of the plate and the center of the plate, and a hole is opened at the barrel wall correspondingly, and the aluminum plate and the barrel foundation are fixed by bolts. A wiring groove 34 is opened in the center of the plate, and a threading hole 32 is opened at the hole 31 to facilitate the wiring of the sensor. Finally, the aluminum plate is wrapped with waterproof tape except for the sensor and the fixing hole, and the sensor line is fixed in the wiring groove 34. The lower end of the aluminum plate is cut to form a drag reduction cutting groove 35.

[0092] The suction bucket installation and pulling-up system includes a lifting beam 16, a wire displacement sensor 17, an extension screw 18, a hydraulic cylinder 19, and a top beam 20 of the model box. The bottom of the hydraulic cylinder 19 is fixed to the top beam 20 of the model box, and the top is connected to the lifting beam 16. The lifting beam 16 is fixed with a wire displacement sensor 17, and the other end of the sensor is hung on the top beam 20 of the model box to measure the lifting height. The central opening of the lifting beam is used to insert the extension screw 18. The tail end of the extension screw 18 is integrally connected to the suction bucket through the vertical screw 21. When the hydraulic cylinder 19 is raised and lowered, the suction bucket is installed and pulled up through the lifting beam 16, the extension screw 18, and the vertical screw 21 fixed together.

[0093] The horizontal loading and measuring system includes a loading pulley 30, a loading wire rope 26, a horizontal load pull ring 36, a servo motor 25, counterweights 22 (m1), 23 (m2), 24 (m3), a top bracket 27 of a model box, a bottom bracket 28 of a model box, and a swingable crossbar 29. The horizontal load pull ring 36 is fixed on the vertical screw 21, and the loading wire rope 26 is connected to the left and right sides respectively. The loading wire rope 26 crosses the bottom bracket 28 of the model box on which the pulley 30 is installed, and is respectively connected to the counterweight 23 (m2) and the swingable crossbar 29. The top bracket 27 of the model box is equipped with a pulley 30, and the two ends of the balancing wire rope 51 are also arranged to cross the pulley, and are respectively connected to the counterweight 24 (m3) and the swingable crossbar 29. The servo motor 25 is installed above the swingable crossbar 29, and the bottom is connected to the counterweight 22 (m1).

[0094] The device studies a method for horizontally loading a suction bucket under high density of sandy soil, and the method comprises the following steps:

[0095] (1) Preparation of sand sample: gravel 3, geotextile 4 and saturated sand 5 are laid in the model box 1 in sequence.

[0096] (2) Suction barrel installation: Before installing the suction barrel, first install a pair of barrel wall sensor mounting devices in the same position as the horizontal load direction of the suction barrel. Then install the vertical screw 21 on the top of the suction barrel. Turn on the hydraulic cylinder 19 to lift the lifting beam 16. Then insert the extension screw 18 into the center of the lifting beam 16. Then, connect the tail end of the extension screw to the vertical screw 21 to ensure that they are tightly connected.

[0097] like Figure 1 As shown, after the equipment is connected and installed, the hydraulic cylinder 19 is started, and the lifting beam 16 is driven downward by the control of the hydraulic system, and the extension screw 18 and the vertical screw 21 are also pressed down, gradually pressing the suction bucket into the soil. During the pressing process, the wire displacement sensor 17 records the lifting height in real time to ensure that the suction bucket is installed to the target position at the expected depth. After the installation is completed, the wire extension screw 18 is removed and the hydraulic cylinder 19 is started to lift the lifting beam 16.

[0098] (3) Horizontal loading: When setting static loading, first connect the vertical screw 21 and the loading wire rope 26 through the horizontal load pull ring 36. The horizontal load pull ring is fixed on the vertical screw 21 with an installation height of h1, and a counterweight 23 (m2) is hung on the lower end of the wire rope to form a static loading system. The LVDT displacement sensor 37 is installed at the upper and lower positions of the vertical screw 21 respectively to measure the horizontal displacement of the upper and lower positions; at the same time, the inclination sensor 38 is fixed on the vertical screw 21 to form a measurement system for measuring the rotation center of the suction bucket. When performing static loading, first hang the counterweight 23 (m2) and monitor the changes in the sensor. When the readings of the LVDT displacement sensor 37 and the inclination sensor 38 remain unchanged for five minutes, increase the mass of the counterweight block 23 (m2), continue to monitor the sensor readings, and repeat this step until any of the following situations occurs: a. The inclination sensor 38 shows that the inclination offset of the suction bucket along the loading direction exceeds 5°; b. The LVDT displacement sensor 37 reaches its limit length and detaches from the vertical screw 21; c. The vertical screw 21 has a visible lateral offset. When any of the above situations occurs, the system is considered to be damaged and the experiment is over. Figure 3 As shown, the length of the suction bucket is 240 mm. When the horizontal load pull ring 36 is 180 mm away from the surface of the suction bucket under static load, the displacement load curve under the continuously increasing counterweight block 23 (m2) is obtained.

[0099] When setting the dynamic loading, the goal is to apply a bending moment waveform of the form M(t) = A·sin(ωt). First, the counterweight 24 (m3) is used as a balancing counterweight to balance the weight of the lever system such as the servo motor 25 and the swingable crossbar 29, thereby ensuring that the system remains balanced in the initial state. On this basis, the required sinusoidal waveform loading is achieved by adjusting the mass of the counterweight 22 (m1) and the counterweight 23 (m2).

[0100] The servo motor 25 is started to make the swingable crossbar 29 reciprocate at a frequency f, and the angular frequency is ω = 2πf. The swinging action of the servo motor causes the left counterweight 22 (m1) to be displaced through the steel wire 26 along with the movement of the swingable crossbar 29, thereby forming a dynamic bending moment.

[0101] The total bending moment M(t) is determined by the difference between the constant bending moment on the right and the dynamic bending moment on the left. 右 Generated by the fixed counterweight 23 (m2), does not change with time, M 右 =m1·

[0102] e (clockwise). Dynamic bending moment M on the left side 左 (t) is generated by the counterweight 22 (m1). When the servo motor drives it to reciprocate, the position of the counterweight changes with time as x(t) = Lsin(ωt). Therefore, the bending moment on the left side is M 左 (t) = m2·e+m2·Lsin(ωt) (counterclockwise)

[0103] Combining the above parts, the total bending moment of the system can be expressed as: M(t) = M 右 -M 左 (t)=(m1-m2)·e-m2·Lsin(ωt).

[0104] Definition of mean bending moment M avg =(m1-m2)·e and amplitude A=m2·L, the total bending moment expression is simplified to:

[0105] M(t)=M avg +Asin(ωt)

[0106] During the dynamic loading process, by adjusting the mass of the counterweights 22 (m1) and 23 (m2), the average value and amplitude of the bending moment can be controlled, thereby achieving the target sinusoidal bending moment waveform. The swing frequency f of the servo motor 25 determines the frequency of the bending moment, so that the swingable crossbar 29 swings back and forth at the set frequency to form a dynamic sinusoidal wave loading effect. During the entire loading process, the accuracy and stability of the bending moment loading can be ensured by monitoring the LVDT displacement sensor 37 and the inclination sensor 38.

[0107] (4) Pulling up the suction bucket: After the suction bucket is destroyed, it needs to be pulled up. In the pulling up process, the lifting function of the hydraulic cylinder 19 is first used to start its upward movement, and the height of the entire system is raised through the lifting beam 16 connected to it. The lifting beam drives the extension screw 18 and the vertical screw 21 to rise together, so that the suction bucket gradually separates from the soil and the pulling out operation is realized.

[0108] In summary, the test device and method of the present invention provide an innovative solution to the offshore wind power industry's research needs on the horizontal load-bearing performance of suction bucket foundations in high-density sand. The device achieves a comprehensive test of the suction bucket foundation by integrating a model box, a suction bucket model system, a suction bucket installation and pull-up system, and a horizontal loading and measurement system. Through the combination of high-efficiency servo motor drive and counterweight block design, the problem of insufficient torque of traditional servo motors is overcome, while providing periodic cyclic load application under high-load conditions, expanding the test range and being suitable for more complex load tests. In addition, by optimizing the sensor layout and circuit design, the device significantly improves the reliability and accuracy of the test data, reduces the test cost and errors caused by external environmental interference.

[0109] The present invention can simulate the actual stress condition of the suction bucket in high-density sand, provide accurate horizontal load data, and provide a scientific basis for the optimal design of the suction bucket foundation. Compared with the traditional system, the device of the present invention is more cost-effective and can better simulate the actual stress state, while saving the cost of using high-precision servo motors and improving the test efficiency. Through the design of the hydraulic and mechanical linkage system, the operation process is simplified and the application efficiency is improved.

[0110] The present invention can be applied to the foundation design and assessment of offshore structures, and the health monitoring and assessment of infrastructure. In industries such as offshore wind power generation, offshore oil and gas, and marine engineering and infrastructure operation and maintenance, the present invention can provide significant value, including improving the rationality of foundation design, construction efficiency, and structural safety and stability, saving construction costs, extending foundation life, reducing operation and maintenance costs, and promoting technological progress in the field of marine engineering.

[0111] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, it can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description of the reference terms "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the absence of mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A test device for studying the horizontal load of a suction bucket under high density of sand, characterized in that: include: Model box for preparing and containing high-density sand samples; Suction bucket model system, used to simulate the installation and loading state of suction bucket foundation in sand; Suction bucket installation and pull-up system, used to control the vertical installation and pull-out operation of the suction bucket model system; Horizontal loading and measuring system, used to apply horizontal static and dynamic loads to the suction bucket model system, including: Pulley, used to change the force direction of the loading wire rope; Steel wire ropes connect the counterweights and the swingable crossbar to transmit the loading force; Servo motor controls the reciprocating motion of the swingable crossbar to achieve dynamic moment loading; The counterweights, including fixed counterweights and adjustable counterweights, work in conjunction with the servo motors to form sinusoidal bending moment loading with specific amplitude and frequency to simulate actual stress conditions by changing their positions and masses; Among them, static loading is formed by the counterweight block, and dynamic loading is formed by driving the counterweight block through the servo motor to generate dynamic bending, and the horizontal displacement of the suction bucket during the loading process and the inclination change of the rotation center of the suction bucket are measured.

2. A test device for studying horizontal load of suction bucket under high density of sand as claimed in claim 1, characterized in that: Gravel, geotextile and sand are arranged in sequence from bottom to top in the model box, and an inlet and outlet valve is provided to realize the saturation and drainage process of the sand.

3. A test device for studying horizontal load of suction bucket under high density of sand as claimed in claim 1 or 2, characterized in that: The suction bucket model system comprises: Suction bucket foundation is made of bottomless and covered steel, with two symmetrical drainage holes on the cover for drainage during installation; The barrel wall sensor installation device surrounds the barrel of the barrel foundation and is equipped with an earth pressure sensor to monitor the load state of the suction barrel foundation in the sand.

4. A test device for studying horizontal load of suction bucket under high density of sand as claimed in claim 3, characterized in that: The barrel wall sensor installation device comprises: Aluminum plates, symmetrically arranged at both ends of the barrel wall, are used to install earth pressure sensors; The fixing holes and routing grooves on the aluminum plate are used to fix the aluminum plate to the barrel wall and guide the sensor line; The holes on the aluminum plate are used to install the earth pressure sensor to measure the pressure of the soil on the barrel wall; Preferably, the total thickness of the aluminum plate is more than 5 mm greater than the thickness of the soil pressure sensor, the length of the aluminum plate is slightly smaller than the height of the bucket foundation, the spacing between the holes on the plate is designed to be smaller than the value obtained by dividing the height of the bucket foundation by the number of sensors, and greater than three times the diameter of the sensor, the distance from the hole to the top and bottom of the aluminum plate is greater than twice the diameter of the sensor, and the hole size is slightly larger than the sensor diameter. Preferably, it also includes a drag-reducing cutting groove located at the lower end of the aluminum plate to reduce the resistance when the suction bucket penetrates.

5. A test device for studying horizontal load of suction bucket under high density of sand as claimed in any one of claims 1 to 4, characterized in that: The suction bucket installation and pulling system includes: A lifting beam is used to support the extension screw and control the vertical movement of the suction bucket; The wire displacement sensor is installed on the lifting beam and extends to the top beam of the model box to monitor the lifting height of the suction bucket in real time; The extended screw rod passes through the center hole of the lifting beam and is connected to the vertical screw rod to transmit the lifting force to the suction bucket; The hydraulic cylinder has its bottom fixed to the top beam of the model box and its top connected to the lifting beam, and the vertical movement of the lifting beam is achieved through oil pressure drive; The lower end of the vertical screw is connected to the extended screw, and the upper end is connected to the suction bucket. The displacement sensor is installed at the upper and lower positions of the vertical screw, and the inclination sensor is fixed on the vertical screw.

6. A test device for studying horizontal load of suction bucket under high density of sand as claimed in any one of claims 1 to 5, characterized in that: The horizontal loading and measuring system specifically comprises: Loading pulley, installed on the upper and lower brackets of the model box, used to guide the wire rope and change the direction of the force; The loading wire rope connects the horizontal load pull ring, the counterweight block and the swingable cross bar to transfer the horizontal load to the suction bucket; The horizontal load pull ring is fixed on the vertical screw and serves as the connection point of the wire rope to ensure accurate transfer of the load; The servo motor controls the reciprocating swing of the swingable crossbar to achieve precise loading of dynamic bending moment; The counterweights, including an adjustable counterweight connected to the swingable crossbar and a fixed counterweight for the balancing system, cooperate with the servo motor to form a sinusoidal bending moment loading with a specific amplitude and frequency; The swingable crossbar connects the servo motor and the counterweight, converting the rotary motion of the servo motor into the reciprocating linear motion of the counterweight to achieve dynamic loading; The model box top bracket and the model box bottom bracket are used to install the pulley and fix the entire horizontal loading system.

7. A method for studying the horizontal load of a suction bucket under high compaction of sand using the test device as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Prepare sand sample: fill the model box with sand to create a high-density sand environment; S2. Suction bucket installation: Install the bucket wall sensor and use the hydraulic system to press the suction bucket into the sand to a predetermined depth; S3, horizontal loading: static load is applied through steel wire rope and counterweight, displacement sensor and inclination sensor are used to monitor displacement and rotation of suction bucket, and counterweight is gradually added until the system is destroyed; servo motor is used to control the swingable cross bar and counterweight to swing back and forth, forming dynamic bending moment loading, realizing sinusoidal waveform loading, and displacement sensor and inclination sensor are continuously used to monitor displacement and rotation of suction bucket; S4. Pulling up the suction bucket: After loading is completed, operate the hydraulic system to pull the suction bucket out of the sand.

8. The method for studying the horizontal load of a suction bucket under high density of sand as claimed in claim 7, characterized in that: In step S1, gravel, geotextile and saturated sand are laid in the model box in sequence; In step S2, before installing the suction bucket, the bucket wall sensor installation device is first installed at a predetermined position, and then the lifting beam is controlled by the hydraulic cylinder, and the suction bucket is pressed into the sand to the target depth by using the extended screw, and the pull-wire displacement sensor monitors the installation depth of the suction bucket in real time; In step S3, the vertical screw is connected to the counterweight by a horizontal load pull ring and a steel wire rope to form a static loading system. During the static loading process, the displacement and rotation of the suction bucket are monitored by a displacement sensor and an inclination sensor, and the counterweight is gradually added until the system is destroyed. During the dynamic loading process, the counterweight is controlled to swing back and forth by a servo motor to form a dynamic bending moment loading, realize sinusoidal waveform loading, and continuously use the displacement sensor and inclination sensor to monitor the displacement and rotation of the suction bucket. In step S4, after the suction bucket is destroyed, the lifting function of the hydraulic cylinder is used to lift the lifting beam and the extension screw to separate the suction bucket from the soil and complete the pulling-up operation.

9. The method for studying horizontal load of suction bucket under high density of sand as claimed in claim 7 or 8, characterized in that: In step S3, static loading specifically includes: Initially load the counterweight to establish the load system, and use the displacement sensor and inclination sensor to monitor the displacement and inclination of the suction bucket; When the monitored displacement and inclination are stable within the specified time, the mass of the counterweight is gradually increased until signs of structural damage appear. The signs of structural damage include any of the following situations: the inclination offset exceeds a predetermined threshold, such as exceeding 5°; the sensor reaches the limit length; or the vertical screw is laterally offset.

10. The method for studying horizontal load of suction bucket under high density of sand as claimed in any one of claims 7 to 9, characterized in that: In step S3, power loading specifically includes: The servo motor is used to control the reciprocating swing of the counterweight to generate a dynamic bending moment waveform with a specific amplitude and frequency; By adjusting the mass of the counterweight, the average value and amplitude of the bending moment can be accurately controlled to form a sinusoidal waveform loading; During the entire dynamic loading process, displacement sensors and inclination sensors are continuously used to monitor the displacement and inclination of the suction bucket to ensure the accuracy of loading and the stability of the system.

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