A kind of geotechnical centrifuge simulation marine environment pile foundation multidirectional loading test device and method thereof

Abstract

The application discloses a kind of soil centrifuge simulation marine environment pile multi-direction loading test device and method thereof, belong to civil centrifuge test technical field, the device includes: model box, square frame, sliding mechanism, at least one aluminum pipe mounting section, rotary transmission mechanism, backing plate, thrust loading mechanism, load sensor, linear variable differential transformer, multiple miniature pore pressure sensor, at least one multi-position laser displacement meter;The method is applied to the above-mentioned one kind of soil centrifuge simulation marine environment pile multi-direction loading test device;Not only can the displacement accumulation of fan foundation in the whole life cycle under the action of multi-direction, cyclic loading under multi-direction loading, stiffness variation law, but also can study the evolution law of different seabed soil settlement, consolidation and other physical and mechanical properties, and is evaluated and analyzed through multi-angle.

Description

Technical Field

[0001] This invention relates to the field of civil centrifuge testing technology, and more specifically, to a geotechnical centrifuge device and method for simulating multi-directional loading tests on pile foundations in a marine environment. Background Technology

[0002] Offshore wind turbines are subjected to horizontal forces and overturning moments from wind and waves from different directions over long periods, exhibiting significant cyclic loading and varying load directions. Therefore, the design of offshore wind turbine monopile foundations must not only meet the unidirectional static ultimate bearing capacity design requirements of the monopile, but also accurately assess the cumulative displacement and stiffness changes of the foundation throughout its entire lifespan under multidirectional, cyclic loads, in relation to the turbine's normal operation. The cyclic loading characteristics of offshore wind turbine monopile foundations are also one of the controlling factors in foundation design.

[0003] In centrifuge model tests, the centrifugal force generated by high-speed rotation applies N times the Earth's gravitational acceleration g (i.e., Ng) to a physical model that is 1 / N the size of the prototype, thereby restoring the stress level of the soil in the model to that of the prototype soil and reflecting the same mechanical behavior.

[0004] Furthermore, although existing large-scale centrifuge pile-soil tests have been extensively studied, most of these studies are unidirectional static and cyclic tests. Existing large-scale centrifuge pile-soil tests lack a multi-directional loading platform, and research on the failure mechanisms of wind turbine foundations under multi-directional loads remains insufficient. Summary of the Invention

[0005] To achieve the above objectives, the present invention provides one solution: a geotextile centrifuge-based multi-directional loading test device for pile foundations in a marine environment. This device is applied to a centrifuge, generating centrifugal force through high-speed rotation to create a hypergravity field, used to simulate multi-directional loading and monitoring of pile foundations in a marine environment. The device includes:

[0006] Model box 1 contains a consolidated and drained soil sample; model piles 2 are vertically inserted into the soil sample.

[0007] The square frame 3 is fixedly installed on the opening of the model box 1, and its length and width dimensions are the same as those of the model box 1.

[0008] The sliding mechanism 4 is installed on the opposite edges of the frame 3;

[0009] At least one aluminum tube mounting section 5 is mounted on the sliding mechanism 4;

[0010] Rotary transmission mechanism 6 is mounted on aluminum tube mounting section 5;

[0011] The tray 7 is mounted on the rotary transmission mechanism 6; the rotary transmission mechanism 6 drives the tray 7 to rotate.

[0012] The thrust loading mechanism 8 is fixedly installed on the support plate 7 and is used to apply thrust to the model pile 2;

[0013] Load sensor 9 is installed at the thrust end of thrust loading mechanism 8;

[0014] The linear variable differential transformer 10 is used to measure the vertical relative displacement between the model pile and the mud surface; it is located on the upper part of the model pile 2.

[0015] Multiple miniature pore pressure sensors 11 are used to measure and evaluate pore water or soil sample pressure or osmotic pressure, and consolidation data; the multiple miniature pore pressure sensors 11 are respectively arranged in soil samples at different depths along the vertical direction of the model box 1;

[0016] At least one multi-position laser displacement device 12 is used to monitor the positional changes of the model assembly in real time; the multi-position laser displacement device 12 is arranged on the side wall along the vertical direction of the model box 1;

[0017] In this process, the sliding mechanism 4 moves the frame 3 directly above the model pile 2, so that the model pile 2 is located inside the aluminum tube installation section 5. The rotary transmission mechanism 6 drives the thrust loading mechanism 8 to rotate and reach the designated position. The thrust loading mechanism 8 applies thrust to the model pile 2 in multiple directions, and the load value applied to the model pile 2 by the thrust end of the thrust loading mechanism 8 is measured by the load sensor 9.

[0018] Furthermore, the sliding mechanism 4 includes:

[0019] Slide rail 401 is mounted on the opposite edges of frame 3;

[0020] Slider 402 is located inside slide rail 401 and slides along the straight line of slide rail 401;

[0021] Among them, the aluminum tube installation section 5 is installed on the slider 402. The aluminum tube installation section 5 slides along the straight direction of the slide rail 401 and moves to the model pile 2, so that the model pile 2 is located inside the aluminum tube installation section 5.

[0022] Furthermore, the rotary transmission mechanism 6 includes:

[0023] Motor mounting bracket 601 is fixedly mounted on the side surface of aluminum tube mounting section 5;

[0024] A drive motor 602 is mounted on a motor mounting base 601;

[0025] The drive gear 603 is connected at its center to the rotation drive end of the drive motor 602;

[0026] Driven gear 604 is mounted on aluminum tube mounting section 5 via upper plate 605, and driven gear 604 meshes with driving gear 603;

[0027] Specifically, the drive motor 602 drives the drive gear 603 to rotate, which in turn drives the driven gear 604 to rotate.

[0028] Furthermore, the thrust loading mechanism 8 includes:

[0029] Track 801 is mounted on tray 7;

[0030] A slide block 802 is mounted on a track 801 and slides along the length of the track 801.

[0031] The sensor mounting base 803 is mounted on the slide 802; the load sensor 9 is mounted on the sensor mounting base 803.

[0032] A hydraulic cylinder 804 is mounted on a support plate 7; the drive extension end of the hydraulic cylinder 804 is horizontal with the rail 801, and the load sensor 9 is connected to the drive extension end of the hydraulic cylinder 804.

[0033] Specifically, the load sensor 9 is pushed by the hydraulic cylinder 804 to apply a thrust to the model pile 2, and the load sensor 9 measures the load value applied to the model pile 2 by the drive extension end of the hydraulic cylinder 804.

[0034] Furthermore, a sliding plate 13 is provided on the slide rail 401, and the sliding plate 13 can move along the length direction of the slide rail 401;

[0035] The linear variable differential transformer 10 is mounted on the sliding plate 13.

[0036] This invention provides another solution: a method for multi-directional loading test of pile foundations in a simulated marine environment using a geotextile centrifuge. This method is applied to the aforementioned multi-directional loading test device for pile foundations in a simulated marine environment using a geotextile centrifuge. The method includes:

[0037] S1. Prepare materials for the experimental setup;

[0038] S2. Prepare soil samples indoors;

[0039] S3. Prepare model box 1;

[0040] S4. Use a crane to lift the model box 1 filled with test soil into the centrifuge room and fix it on the test table;

[0041] S5. When not in use, cover the surface of the soil sample inside the model box with a layer of damp geotextile.

[0042] S6. Start the centrifuge test. After the centrifuge acceleration is increased to 100g, monitor the micropore pressure data at all times. When the change in soil pore pressure over 1 hour is within 1 kPa, the soil sample is considered to be completely consolidated.

[0043] S7. Conduct static loading tests. The servo electric cylinder controller drives the horizontal servo electric cylinder to work and records the dynamic response of the single pile foundation and the surrounding soil sample, thereby obtaining the static loading response of the single pile and determining the foundation bearing capacity Fu.

[0044] S8. Repeat the cyclic reconsolidation process of S7 for a total of 9 rounds at cyclic amplitudes of 25% Fu, 45% Fu, and 65% Fu.

[0045] S9. Stop the centrifuge and use a new model single pile to carry out a single pile unidirectional cyclic reconsolidation test. After the centrifuge acceleration is increased to 100g, monitor the micro pore pressure data at all times until the soil sample is completely consolidated.

[0046] S10, repeat the cyclic reconsolidation process of S8 for a total of 9 rounds at cyclic amplitudes of 25% Fu, 45% Fu, and 65% Fu.

[0047] Furthermore, in S4: a camera, load sensor 9, linear variable differential transformer 10, miniature pore pressure sensor 11, and laser displacement sensor 12 are fixed inside the model box 1.

[0048] Two laser displacement sensors 12 are placed at a position of 0.1m on the soil sample to measure the horizontal deformation of the single pile body;

[0049] A miniature pore pressure sensor 11 was installed at depths of 0.2m, 0.3m and 0.4m below the soil sample to monitor the pore pressure response of the soil around the single pile during the loading process.

[0050] Furthermore, in S6: during the consolidation process, the soil settlement value is measured by the linear variable differential transformer 13;

[0051] The degree of soil consolidation can be determined based on the measured soil settlement value;

[0052] After the soil consolidation was completed, a T-bar penetration test at 100g was conducted to measure the distribution of the undrained shear strength of the soil.

[0053] The centrifuge takes at least 35 hours to operate continuously at 100g.

[0054] Furthermore, in S8: the centrifuge takes at least 10 hours to run continuously at 100g.

[0055] In summary, the present invention has the following beneficial effects:

[0056] By setting up a geotechnical centrifuge to simulate a multi-directional loading test device for pile foundations in a marine environment, we can not only study the cumulative displacement and stiffness variation of wind turbine foundations throughout their entire life cycle under multi-directional and cyclic loading, but also study the evolution of physical and mechanical properties such as settlement and consolidation of different seabed soils, and conduct multi-angle evaluation and analysis. Attached Figure Description

[0057] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0058] Figure 1 This is a schematic diagram of the structure of a geotextile centrifuge multi-directional loading test device for simulating a marine environment pile foundation according to Embodiment 1 of the present invention;

[0059] Figure 2 This is a schematic diagram of the structure of a geotextile centrifuge multi-directional loading test device for simulating marine environment pile foundations after removing the model box, as described in Embodiment 1 of the present invention.

[0060] Figure 3 For the present invention Figure 2 The main view;

[0061] Figure 4 This is a schematic diagram of the thrust loading mechanism and rotary transmission mechanism in Embodiment 1 of the present invention;

[0062] Figure 5 This is a diagram showing the installation positions of the load sensor, linear variable differential transformer, miniature pore pressure sensor, and laser displacement device in Embodiment 1 of the present invention.

[0063] Figure 6 This is a force-displacement diagram of the prototype pile head load when the centrifuge model in Embodiment 2 of this invention is subjected to static loading.

[0064] Figure 7 This is the load-displacement diagram of the prototype pile head when the centrifuge model of Embodiment 2 of this invention is subjected to cyclic unidirectional loading.

[0065] Figure 8 This is a graph showing the change in pore pressure during the soil cyclic reconsolidation process in Example 2 of this invention.

[0066] Figure 9 This is a schematic diagram of the load recording in the x and y directions of the centrifuge model under cyclic unidirectional and multidirectional loading in Embodiment 2 of the present invention.

[0067] The labels in the attached diagram are:

[0068] 1. Model box; 2. Model pile; 3. Frame; 4. Sliding mechanism; 401. Slide rail; 402. Slider;

[0069] 5. Aluminum tube installation section;

[0070] 6. Rotary transmission mechanism; 601. Motor mounting base; 602. Drive motor; 603. Driving gear; 604. Driven gear; 605. Upper plate;

[0071] 7. Pallet;

[0072] 8. Thrust loading mechanism; 801. Rail; 802. Slide; 803. Sensor mounting base; 804. Hydraulic cylinder;

[0073] 9. Load sensor; 10. Linear variable differential transformer; 11. Miniature pore pressure sensor; 12. Laser displacement device; 13. Sliding plate. Detailed Implementation

[0074] To make the technical means, creative features, objectives and effects of this invention easier to understand, the technical solutions in the specific embodiments of this invention are described clearly and completely below to further illustrate this invention. Obviously, the specific embodiments described are only a part of the embodiments of this invention, and not all of them.

[0075] Example 1

[0076] like Figures 1-5 As shown, a geotextile centrifuge-based multi-directional loading test device for pile foundations in a marine environment is disclosed. This device, applied to a centrifuge, generates centrifugal force through high-speed rotation, creating a hypergravity field to simulate multi-directional loading and monitoring of pile foundations in a marine environment. The device includes:

[0077] Model box 1 contains a consolidated and drained soil sample; model piles 2 are vertically inserted into the soil sample.

[0078] Specifically, model box 1 consists of a rectangular box measuring 1m*1.2m*1.2m, with a layer of sand at the bottom of the seabed serving as a filter layer to prevent the dominant current from disturbing the upper soil.

[0079] Specifically, the model pile 2 is manufactured by machining 7075 aluminum alloy hollow tubes in two stages. It comes in three diameters: 0.04m, 0.06m, and 0.1m, corresponding to thicknesses of 2mm, 2mm, and 3.2mm. The model pile 2 can be used to study the interaction between the seabed soil and the pile, and can also be used to investigate the bearing characteristics of the prototype pile through centrifuge tests.

[0080] The square frame 3 is fixedly installed on the opening of the model box 1, and its length and width dimensions are the same as those of the model box 1.

[0081] Specifically, the frame 3 is connected by snap-fit ​​screws to precisely position the loading device.

[0082] The sliding mechanism 4 is installed on the opposite edges of the frame 3;

[0083] Specifically, the sliding mechanism 4 includes:

[0084] Slide rail 401 is mounted on the opposite edges of frame 3;

[0085] Slider 402 is located inside slide rail 401 and slides along the straight line of slide rail 401;

[0086] Among them, the aluminum tube installation section 5 is installed on the slider 402. The aluminum tube installation section 5 slides along the straight direction of the slide rail 401 and moves to the model pile 2, so that the model pile 2 is located inside the aluminum tube installation section 5.

[0087] The device also includes at least one aluminum tube mounting section 5, which is mounted on the sliding mechanism 4;

[0088] The device also includes a rotary transmission mechanism 6, which is mounted on the aluminum tube mounting section 5;

[0089] Specifically, the rotary transmission mechanism 6 includes:

[0090] Motor mounting bracket 601 is fixedly mounted on the side surface of aluminum tube mounting section 5;

[0091] A drive motor 602 is mounted on a motor mounting base 601;

[0092] The drive gear 603 is connected at its center to the rotation drive end of the drive motor 602;

[0093] Driven gear 604 is mounted on aluminum tube mounting section 5 via upper plate 605, and driven gear 604 meshes with driving gear 603;

[0094] Specifically, the drive motor 602 drives the drive gear 603 to rotate, which in turn drives the driven gear 604 to rotate.

[0095] The device also includes a tray 7, which is mounted on a rotary transmission mechanism 6; the rotary transmission mechanism 6 drives the tray 7 to rotate.

[0096] The device also includes a thrust loading mechanism 8, which is fixedly installed on the support plate 7 and is used to apply thrust to the model pile 2.

[0097] Specifically, the thrust loading mechanism 8 includes:

[0098] Track 801 is mounted on tray 7;

[0099] A slide block 802 is mounted on a track 801 and slides along the length of the track 801.

[0100] The sensor mounting base 803 is mounted on the slide 802; the load sensor 9 is mounted on the sensor mounting base 803.

[0101] A hydraulic cylinder 804 is mounted on a support plate 7; the drive extension end of the hydraulic cylinder 804 is horizontal with the rail 801, and the load sensor 9 is connected to the drive extension end of the hydraulic cylinder 804.

[0102] Specifically, the load sensor 9 is pushed by the hydraulic cylinder 804 to apply a thrust to the model pile 2, and the load sensor 9 measures the load value applied to the model pile 2 by the drive extension end of the hydraulic cylinder 804.

[0103] The device also includes a load sensor 9, which is installed at the thrust end of the thrust loading mechanism 8;

[0104] The device also includes a linear variable differential transformer 10, used to measure the vertical relative displacement between the model pile and the mud surface; it is located on the upper part of the model pile 2.

[0105] The device also includes multiple micro pore pressure sensors 11 for measuring and evaluating pore water or soil pressure or osmotic pressure, and consolidation data; the multiple micro pore pressure sensors 11 are respectively arranged in soil samples at different depths along the vertical direction of the model box 1;

[0106] The device also includes at least one multi-position laser displacement device 12 for real-time monitoring of the position changes of the model assembly; the multi-position laser displacement device 12 is arranged on the side wall along the vertical direction of the model box 1;

[0107] In this process, the sliding mechanism 4 moves the frame 3 directly above the model pile 2, so that the model pile 2 is located inside the aluminum tube installation section 5. The rotary transmission mechanism 6 drives the thrust loading mechanism 8 to rotate and reach the designated position. The thrust loading mechanism 8 applies thrust to the model pile 2 in multiple directions, and the load value applied to the model pile 2 by the thrust end of the thrust loading mechanism 8 is measured by the load sensor 9.

[0108] Furthermore, a sliding plate 13 is provided on the slide rail 401, and the sliding plate 13 can move along the length direction of the slide rail 401;

[0109] The linear variable differential transformer 10 is mounted on the sliding plate 13.

[0110] Its working process is as follows: the slider 402 slides on the slide rail 401, thereby driving the rotary transmission mechanism 6 and the thrust loading mechanism 8 to move to the designated position, so that the model pile 2 is located in the aluminum tube installation section 5. The drive motor 602 is turned on to drive the active gear 603 to rotate, thereby driving the driven gear 604 to rotate, driving the thrust loading mechanism 8 to rotate to the designated angle. The hydraulic cylinder 804 is turned on to push the load sensor 9 to apply thrust to the model pile 2. The load sensor 9 measures the load value applied to the model pile 2 by the drive extension end of the hydraulic cylinder 804. The linear variable differential transformer 10 is used to measure the vertical relative displacement between the model pile and the mud surface. The micro pore pressure sensor 11 is used to measure and evaluate the pore water or soil sample pressure or osmotic pressure and consolidation data. The laser displacement device 12 is used to monitor the position change of the model pile in real time.

[0111] Example 2

[0112] A method for multi-directional loading test of pile foundations in a marine environment using a geotextile centrifuge, the method being applied to the multi-directional loading test device for pile foundations in a marine environment using a geotextile centrifuge as described in Example 1 above, the method comprising:

[0113] S1. Prepare materials for the experimental setup;

[0114] Specifically, the materials used in its production include: wooden boards, thin steel plates, linear sliding guides, screws, pulleys, jacks, steel wire ropes, weight pans and weights, geotextile, and data cables.

[0115] S2. Prepare soil samples indoors;

[0116] Specifically, taking kaolin as an example, kaolin powder and water are mixed in a certain proportion, stirred, poured into a mold box, and then the soil consolidation and drainage process begins, with a maximum consolidation stress of 20 kPa. After 1g of consolidation is completed, the surface weight is removed.

[0117] S3. Prepare model box 1;

[0118] Specifically, four steel trusses are used in a cross-shaped fixing frame at the opening of the model box to secure the model piles. The test soil is clay; after being mixed and prepared, the clay is first introduced and allowed to settle statically before being vertically driven into the model pile using jacks. Miniature pore pressure gauges are either pre-embedded or forcibly inserted into the soil using a thin steel pipe.

[0119] S4. Use a crane to lift the model box 1 filled with test soil into the centrifuge room and fix it on the test table;

[0120] like Figure 5 As shown, specifically in S4: a camera, load sensor 9, linear variable differential transformer 10, miniature pore pressure sensor 11, and laser displacement sensor 12 are fixed inside the model box 1.

[0121] Two laser displacement sensors 12 are placed at a position of 0.1m on the soil sample to measure the horizontal deformation of the single pile body;

[0122] A miniature pore pressure sensor 11 was installed at depths of 0.2m, 0.3m and 0.4m below the soil sample to monitor the pore pressure response of the soil around the single pile during the loading process.

[0123] S5. When not in use, cover the surface of the soil sample in the model box with a layer of damp geotextile to prevent moisture evaporation.

[0124] S6. Start the centrifuge test. After the centrifuge acceleration is increased to 100g, monitor the micropore pressure data at all times. When the change in soil pore pressure over 1 hour is within 1 kPa, the soil sample is considered to be completely consolidated.

[0125] Specifically, in S6: During the consolidation process, the soil settlement value is measured by the linear variable differential transformer 13;

[0126] The degree of soil consolidation can be determined based on the measured soil settlement value;

[0127] After the soil consolidation was completed, a T-bar penetration test at 100g was conducted to measure the distribution of the undrained shear strength of the soil.

[0128] The centrifuge takes at least 35 hours to operate continuously at 100g.

[0129] like Figure 6 As shown in Figure S7, a static loading test is carried out. The servo electric cylinder controller drives the horizontal servo electric cylinder to work and records the dynamic response of the single pile foundation and the surrounding soil sample, thereby obtaining the static loading response of the single pile and determining the foundation bearing capacity Fu.

[0130] S8. Repeat the cyclic reconsolidation process of S7 for a total of 9 rounds at cyclic amplitudes of 25% Fu, 45% Fu, and 65% Fu.

[0131] Specifically, in S8: the centrifuge takes at least 10 hours to run continuously at 100g.

[0132] S9. Stop the centrifuge and use a new model single pile to carry out a single pile unidirectional cyclic reconsolidation test. After the centrifuge acceleration is increased to 100g, monitor the micro pore pressure data at all times until the soil sample is completely consolidated.

[0133] like Figure 7 As shown, specifically, for any given cyclic amplitude, there are 3 rounds of cyclic loading with equal amplitude. After each round of loading, the load is unloaded to 0, the centrifuge continues to run, and the soil around the pile begins to reconsolidate. The excess pore pressure accumulated in the previous cycle gradually dissipates. Once the excess pore pressure has completely dissipated, the pore pressure result is as follows: Figure 8 As shown, after the soil is completely consolidated, the next cycle of loading is performed. The above steps are repeated until a total of 9 cycles of cyclic reconsolidation are completed under 3 different cycle amplitudes.

[0134] S10, repeat the cyclic reconsolidation process of S8 for a total of 9 rounds at cyclic amplitudes of 25% Fu, 45% Fu, and 65% Fu.

[0135] like Figures 8-9 As shown, specifically, the experiment included sequential cyclic reconsolidation stages with different amplitudes in two mutually perpendicular directions to investigate the influence of loading direction and amplitude on the cyclic reconsolidation effect under complex cyclic loading conditions. For one cyclic amplitude, it included three rounds of multi-directional cyclic loading with equal amplitude. First, it was cyclically loaded 100 times from one direction, and then cyclically loaded 100 times from the direction perpendicular to that direction. After each round of cyclic loading, the load was unloaded to 0, the centrifuge continued to run, and the soil around the pile began to reconsolidate. The excess pore pressure accumulated in the previous cycle gradually dissipated. After the excess pore pressure was completely dissipated, that is, after the soil was completely consolidated, the next round of cyclic loading was carried out.

[0136] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A geotextile centrifuge-based multi-directional loading test device for pile foundations in a marine environment, characterized in that, This device, applied to a centrifuge, generates centrifugal force through high-speed rotation, creating a hypergravity field. It is used to simulate multi-directional loading and monitoring of pile foundations in a marine environment. The device includes: Model box (1), the model box (1) contains a soil sample after consolidation and drainage; model piles (2) are vertically inserted into the soil sample. The square frame (3) is fixedly installed on the opening of the model box (1), and its length and width dimensions are consistent with the length and width dimensions of the model box (1); A sliding mechanism (4) is mounted on the opposite edge of the frame (3); At least one aluminum tube mounting section (5) is mounted on the sliding mechanism (4); A rotary transmission mechanism (6) is mounted on an aluminum tube mounting section (5); The pallet (7) is mounted on the rotary transmission mechanism (6); the rotary transmission mechanism (6) drives the pallet (7) to rotate. The thrust loading mechanism (8) is fixedly installed on the support plate (7) and is used to load thrust onto the model pile (2); A load sensor (9) is installed at the thrust end of the thrust loading mechanism (8); A linear variable differential transformer (10) is used to measure the vertical relative displacement between the model pile and the mud surface; it is located on the upper part of the model pile (2); Multiple micro pore pressure sensors (11) are used to measure and evaluate pore water or soil pressure or osmotic pressure, and consolidation data; multiple micro pore pressure sensors (11) are respectively arranged in soil samples at different depths along the vertical direction of the model box (1); At least one multi-position laser displacement device (12) is used to monitor the position change of the model assembly in real time; the multi-position laser displacement device (12) is arranged on the side wall along the vertical direction of the model box (1); In this process, the sliding mechanism (4) moves the frame (3) directly above the model pile (2), so that the model pile (2) is located inside the aluminum tube installation section (5). The rotating transmission mechanism (6) drives the thrust loading mechanism (8) to rotate and reach the designated position. The thrust loading mechanism (8) applies thrust to the model pile (2) in multiple directions, and the load sensor (9) measures the load value applied to the model pile (2) by the thrust end of the thrust loading mechanism (8).

2. The geotextile centrifuge multi-directional loading test device for simulating marine environment pile foundations according to claim 1, characterized in that: The sliding mechanism (4) includes: The slide rail (401) is mounted on the opposite edge of the frame (3); The slider (402) is located inside the slide rail (401), and the slider (402) slides along the straight direction of the slide rail (401); Among them, the aluminum tube installation section (5) is installed on the slider (402). The aluminum tube installation section (5) slides along the straight direction of the slide rail (401) and moves to the model pile (2), so that the model pile (2) is located inside the aluminum tube installation section (5).

3. The geotextile centrifuge multi-directional loading test device for simulating marine environment pile foundations according to claim 2, characterized in that: The rotary transmission mechanism (6) includes: Motor mounting bracket (601) is fixedly mounted on the side surface of aluminum tube mounting section (5); A drive motor (602) is mounted on a motor mounting bracket (601). The drive gear (603) is connected at its center to the rotation drive end of the drive motor (602); Driven gear (604) is mounted on aluminum tube mounting section (5) via upper plate (605), and driven gear (604) meshes with driving gear (603); In this process, the drive motor (602) drives the active gear (603) to rotate, which in turn drives the driven gear (604) to rotate.

4. The geotextile centrifuge multi-directional loading test device for simulating marine environment pile foundations according to claim 3, characterized in that: The thrust loading mechanism (8) includes: The track (801) is mounted on the pallet (7); A slide (802) is mounted on a track (801) and slides along the length of the track (801); A sensor mounting base (803) is mounted on a slide (802); a load sensor (9) is mounted on the sensor mounting base (803); A hydraulic cylinder (804) is mounted on a pallet (7); the drive extension end of the hydraulic cylinder (804) is horizontal to the rail (801), and the load sensor (9) is connected to the drive extension end of the hydraulic cylinder (804). In this process, the load sensor (9) is pushed by the hydraulic cylinder (804) to apply thrust to the model pile (2), and the load sensor (9) measures the load value applied to the model pile (2) by the drive extension end of the hydraulic cylinder (804).

5. The geotextile centrifuge multi-directional loading test device for simulating marine environment pile foundations according to claim 2, characterized in that: A sliding plate (13) is provided on the slide rail (401), and the sliding plate (13) can move along the length direction of the slide rail (401); The linear variable differential transformer (10) is mounted on the sliding plate (13).

6. A method for multi-directional loading test of pile foundations in a marine environment using a geotextile centrifuge, characterized in that, This method is applied to a geotextile centrifuge multi-directional loading test device for simulating marine environment pile foundations as described in any one of claims 1-5, and the method includes: S1. Prepare materials for the experimental setup; S2. Prepare soil samples indoors; S3. Prepare the model box (1); S4. Use a crane to lift the model box (1) filled with test soil into the centrifuge room and fix it on the test table; S5. When not in use, cover the surface of the soil sample inside the model box with a layer of damp geotextile. S6. Start the centrifuge test. After the centrifuge acceleration is increased to 100g, monitor the micropore pressure data at all times. When the change in soil pore pressure over 1 hour is within 1 kPa, the soil sample is considered to be completely consolidated. S7. Conduct static loading tests. The servo electric cylinder controller drives the horizontal servo electric cylinder to work and records the dynamic response of the single pile foundation and the surrounding soil sample, thereby obtaining the static loading response of the single pile and determining the foundation bearing capacity Fu. S8. Repeat the S7 cyclic reconsolidation process for a total of 9 rounds at cyclic amplitudes of 25%Fu, 45%Fu, and 65%Fu. S9. Stop the centrifuge and use a new model single pile to carry out a single pile unidirectional cyclic reconsolidation test. After the centrifuge acceleration is increased to 100g, monitor the micro pore pressure data at all times until the soil sample is completely consolidated. S10, repeat the S8 cyclic reconsolidation process for a total of 9 rounds at cyclic amplitudes of 25%Fu, 45%Fu, and 65%Fu.

7. A method for multi-directional loading test of pile foundations simulating marine environment using a geotextile centrifuge according to claim 6, characterized in that: In S4: a camera, load sensor (9), linear variable differential transformer (10), miniature pore pressure sensor (11), and laser displacement sensor (12) are fixed inside the model box (1). Two laser displacement sensors (12) were placed at a position of 0.1m on the soil sample to measure the horizontal deformation of the single pile body; A miniature pore pressure sensor (11) was installed at depths of 0.2m, 0.3m and 0.4m below the soil sample to monitor the pore pressure response of the soil around the single pile during the loading process.

8. A method for multi-directional loading test of pile foundations simulating marine environment using a geotextile centrifuge according to claim 6, characterized in that: In S6: During the consolidation process, the soil settlement value is measured by a linear variable differential transformer (10); The degree of soil consolidation is determined based on the measured soil settlement value; After the soil consolidation was completed, a T-bar penetration test at 100g was conducted to measure the distribution of the undrained shear strength of the soil. The centrifuge takes at least 35 hours to operate continuously at 100g.

9. A method for multi-directional loading test of pile foundations in a simulated marine environment using a geotextile centrifuge, as described in claim 6, is characterized in that: In S8: The centrifuge takes at least 10 hours to run continuously at 100g.

Images