Geocell mechanical property testing device and method of multi-cell interaction mechanism

Abstract

The present application relates to the technical field of geotechnical reinforcement, in particular to a geocell mechanical property testing device of multi-cell interaction mechanism, comprising a pressure applying assembly, a sample assembly is arranged below the pressure applying end of the pressure applying assembly, the pressure applying assembly is used for applying pressure to the sample assembly, the sample assembly is electrically connected with a collection assembly, the collection assembly is used for real-time monitoring and recording parameters in the test process; the sample assembly comprises a model sample, and a bearing plate is arranged above and below the model sample; the model sample comprises a plurality of geocells, the plurality of geocells are stacked up and down, a strain gauge is arranged on each outer wall of the central cell of the geocell, and the strain gauges are electrically connected with the collection assembly. The present application can accurately simulate and measure the stress-strain characteristics under the multi-cell interaction mechanism, and provides important experimental basis and technical support for revealing the synergistic working mechanism of the reinforced structure and perfecting the geocell design theory.

Description

Technical Field

[0001] This invention relates to the field of soil and rock reinforcement technology, and in particular to a geocell mechanical property testing device and method based on a multi-cell interaction mechanism. Background Technology

[0002] Geocell reinforcement technology has gained widespread engineering attention and application due to its outstanding advantages such as convenient transportation, adaptability to complex terrain, good economy, and eco-friendliness. Geocells are three-dimensional mesh geosynthetic materials formed by connecting wide strips of high-molecular polymers (such as high-density polyethylene, polypropylene, or polyester) through ultrasonic welding, riveting, insertion, or injection molding. Through the three-dimensional mesh structure, it effectively constrains the soil and significantly improves the mechanical properties of the soil, including shear strength, stiffness, and bearing capacity. Therefore, it is widely used in many important engineering fields such as foundation treatment, railway and highway subgrade reinforcement, retaining wall structure construction, and slope protection.

[0003] In the research of geocell reinforcement technology, its reinforcement mechanism and reinforcement effect have always been the core issues in the field of geotechnical engineering. Existing research focuses on the core working mechanism of this technology, which mainly includes three-dimensional constraint effect, stress diffusion mechanism and load redistribution behavior, and a large amount of systematic theoretical, experimental and numerical simulation work has been carried out.

[0004] Studies have shown that the performance of geocell reinforced systems is influenced by multiple factors, including the material stiffness of the cells themselves, joint strength, mechanical properties of welded joints, compaction degree, shear dilatation characteristics and interparticle friction behavior of the fill material, as well as geometric parameters such as the arrangement, height and weld spacing of the reinforcement layers. These factors jointly regulate the overall stiffness of the reinforced system and the soil-cell interface interaction mechanism, thereby having a decisive impact on the settlement development, bearing capacity evolution and failure mode of the foundation.

[0005] Although existing research has provided important theoretical basis for the design and application of geocell reinforced soil structures, there is still a lack of systematic quantification and unified design criteria for their response laws in terms of size effect and multi-grid interaction mechanism.

[0006] However, in practical engineering, geocell reinforced structures are mainly used to bear vertical loads, and their boundary conditions and stress paths are relatively clear. Therefore, model tests have become an important means to reveal their mechanical response and deformation mechanism. When axial loads are applied to the reinforced system, significant vertical and horizontal stress redistribution occurs inside the filler. Horizontal stresses act on the cell sidewalls, forming active earth pressures that drive the cell walls to undergo outward displacement and circumferential tensile strain. At the same time, passive earth pressures are generated between adjacent cells due to deformation coordination, forming a mutual constraint effect. This complex interaction mechanism directly determines the overall stiffness and stress diffusion capacity of the reinforced system.

[0007] However, existing methods for calculating the strength and stiffness of geocell-reinforced soil do not consider the influence of geocell creep deformation on the interaction between reinforcement and soil. Furthermore, they all use single circular cells as the research object, equating square, honeycomb, and rhomboid cells to circular cells by using the method of equal area, without considering the influence of the cell cross-sectional shape and the interaction between multiple cells. Moreover, existing calculation results for single-cell soil strength still differ from measured results for multi-cell geocell soil strength; single-cell soil strength calculation methods cannot be directly applied to multi-cell geocells. This makes the current multi-cell interaction mechanism of geocells a relatively weak or even often overlooked key aspect of design theory. In particular, the lack of experimental devices and testing methods that can realistically simulate multi-cell collaborative work makes it impossible to accurately reveal the development law of circumferential tensile force, strain distribution pattern, and filler constraint state. This mechanism has a decisive impact on the settlement control effect and long-term performance of reinforced structures.

[0008] Currently, there is a lack of reliable experimental methods and theoretical models, which leads to practical engineering designs often relying on experience or simplified assumptions, making it difficult to fully reflect the true mechanical response and failure mechanism of the structure.

[0009] Therefore, there is an urgent need for a testing device and method for the mechanical properties of geocells based on multi-cell interaction mechanisms. This method aims to reveal the interaction mechanism and influencing factors between geocells and fill soil, as well as the interaction mechanism among multiple cells. It also aims to establish a calculation model for the stress-strain response of geocell-reinforced soil, propose calculation methods for the equivalent strength and equivalent stiffness of geocell-reinforced soil, and methods for verifying the stiffness of geocell strips and the strength of nodes. This will provide calculation parameters for the design of geocell-reinforced soil structures and serve the engineering practice of soft soil foundation treatment and slope reinforcement in infrastructure construction such as highways, railways, airports, and substations. Furthermore, the test results obtained based on this testing device can be used to verify the correctness and reliability of the stress-strain model for reinforced soil. Summary of the Invention

[0010] The purpose of this invention is to provide a testing device and method for the mechanical properties of geocells based on multi-cell interaction mechanisms, so as to solve the problems existing in the prior art.

[0011] To achieve the above objectives, the present invention provides the following solution: a geocell mechanical property testing device based on a multi-cell interaction mechanism, comprising a pressure-applying component, a sample assembly disposed below the pressure-applying end of the pressure-applying component, the pressure-applying component being used to apply pressure to the sample assembly, the sample assembly being electrically connected to a data acquisition component, the data acquisition component being used to monitor and record parameters during the test in real time; the sample assembly comprising a model sample, with bearing plates disposed above and below the model sample respectively; the model sample comprising multiple geocells, the multiple geocells being stacked vertically, strain gauges being disposed on the outer wall of each central cell of the geocells, and the strain gauges being electrically connected to the data acquisition component.

[0012] Preferably, the pressure application assembly includes a reaction frame, and a pressure application part is installed at the top end of the reaction frame facing the geocell.

[0013] Preferably, the central axis of the loading head of the pressurizing part is on the same central axis as the central axis of the geocell.

[0014] Preferably, the central axis of the geocell is on the same central axis as the central axes of the two bearing plates.

[0015] Preferably, handles are fixedly connected to both sides of the top surface of the support plate, and the two handles are arranged opposite to each other.

[0016] Preferably, the geocells are arranged in an equilateral quadrilateral shape.

[0017] Preferably, the strain gauges are also disposed on the side walls of the edge grids adjacent to the central grid.

[0018] Preferably, the acquisition component includes a data acquisition instrument, which is connected to the strain gauge via a cable.

[0019] Preferably, the data acquisition device is located on one side of the reaction frame.

[0020] A method for testing the mechanical properties of geocells based on multi-cell interaction mechanisms.

[0021] To quantify the relationship between the mechanical properties of multi-grid structures and single-grid structures, a multi-grid effect factor is proposed. E f The concept of is expressed as: In the formula, The multi-grid effect intensity enhancement factor is defined as the extreme value of the horizontal strain in a multi-grid system under the same axial strain conditions. ) and the extreme values ​​of horizontal strain in a single grid ( The ratio of ), i.e. .

[0022] To establish a quantitative prediction model for strip strain in multi-grid geocell reinforced structures, multi-grid effect factors were integrated. The acquisition components are used to monitor and record parameters during the experiment in real time, and empirical formulas are fitted through nonlinear regression analysis. Based on the strain gradient distribution characteristics and the mesh synergy mechanism, a multi-grid horizontal strain model is proposed. The expression is: In the formula: , and These are material property parameters, determined through fitting experimental data.

[0023] The present invention discloses the following technical effects: This invention forms a model specimen by stacking multiple geocells, applies pressure to the model specimen using a pressure-applying component, and monitors and records parameters in real time during the test using a data acquisition component. This allows for accurate simulation and measurement of stress-strain characteristics under the multi-cell interaction mechanism, providing important experimental evidence and technical support for revealing the collaborative working mechanism of reinforced structures and improving geocell design theory. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the overall front view of the present invention; Figure 2 This is a schematic diagram of the sample assembly structure of the present invention; Figure 3 This is a schematic diagram of the model sample structure of the present invention; Figure 4 This is a schematic diagram of the structure of multiple strain gauges installed on the outer wall of the central grid according to the present invention; Figure 5 This is a schematic diagram showing the setting of measuring points in the intermediate transition layer of the present invention; Figure 6 A schematic diagram showing the setup of the top and bottom measuring points of the model sample of this invention; Figure 7 This is a schematic diagram showing the setting of measurement points in the key layer of this invention; Figure 8 This is a front view schematic diagram of the adjustment component of the present invention; Figure 9 This is a side view of the first movable plate structure of the present invention; Figure 10 This is a side view of the second movable plate structure of the present invention; Figure 11 This is a schematic diagram of the bearing capacity-settlement relationship curve for a grid with a side length of 125mm according to the present invention. Figure 12 This is a schematic diagram of the bearing capacity-settlement relationship curve for a grid with a side length of 150mm according to the present invention. Figure 13 This is a schematic diagram of the transverse strain-bearing capacity relationship curve of the 1×1 type mesh of the present invention; Figure 14 This is a schematic diagram of the transverse strain-bearing capacity relationship curve of the 2×2 type mesh of the present invention; Figure 15 This is a schematic diagram of the transverse strain-bearing capacity relationship curve of the 3×3 type mesh of the present invention; Figure 16 This is a schematic diagram of the transverse strain-bearing capacity relationship curve of the 3×3 intermediate layer mesh of the present invention; Figure 17 This is a schematic diagram of the vertical strain law of the 1×1 type mesh of the present invention; Figure 18 This is a schematic diagram of the vertical strain law of the 2×2 type mesh of the present invention; Figure 19 This is a schematic diagram of the vertical strain law of the 3×3 type mesh of the present invention; Figure 20 This invention relates to the axial stress mechanism of the single-grid geocell reinforcement effect. Figure 21 The present invention relates to the compressive stress mechanism of the reinforcement effect of a single-grid geocell. Figure 22 This invention relates to the constraint stress mechanism of the single-grid geocell reinforcement effect. Figure 23 This invention provides a reinforcing mesh for the multi-grid geocells. Figure 24 This invention relates to the characteristics of a multi-grid geocell reinforced flexible raft slab. Figure 25 This is a schematic diagram illustrating the contribution of the cell membrane of the 1×1 type geocell of the present invention to surrounding factors; Figure 26 This is a schematic diagram illustrating the contribution of the cell membrane of the 2×2 type geocell of the present invention to surrounding factors; Figure 27 This is a schematic diagram illustrating the contribution of the cell membrane of the 3×3 type geocell of the present invention to surrounding factors; Figure 28 This is a schematic diagram illustrating the contribution of the cell membrane of the 6×6 grid geocell of the present invention to surrounding factors; Figure 29 A comparison of theoretical and experimental results for the 125mm mesh side length of this invention; Figure 30 A comparison of theoretical and experimental results for a mesh side length of 150mm in this invention; The components include: 1. Reaction frame; 2. Loading head; 3. Bearing plate; 4. Model specimen; 5. Data acquisition instrument; 6. Geocell; 7. Central cell; 8. Strain gauge; 9. Handle; 10. Support plate; 11. First hydraulic cylinder; 12. First movable plate; 13. Second hydraulic cylinder; 14. Second movable plate; 121. First fixed block; 122. First motor; 123. First transmission shaft; 124. First bevel gear; 125. Second bevel gear. ; 126. Third bevel gear; 127. Second drive shaft; 128. Fourth bevel gear; 129. Fifth bevel gear; 130. Sixth bevel gear; 131. First lead screw; 132. First slide groove; 133. First slider; 134. First push plate; 135. Second fixing block; 141. Third fixing block; 142. Second motor; 143. Second lead screw; 144. Second slide groove; 145. Second slider; 146. Second push plate. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Reference Figures 1 to 10 This invention provides a geocell mechanical property testing device based on a multi-cell interaction mechanism, comprising a pressure application component, a sample assembly disposed below the pressure application end of the pressure application component, the pressure application component being used to apply pressure to the sample assembly, and a data acquisition component electrically connected to the sample assembly, the data acquisition component being used to monitor and record parameters during the test in real time; the sample assembly includes a model sample 4, with bearing plates 3 disposed above and below the model sample 4 respectively; the model sample 4 includes multiple geocells 6, the multiple geocells 6 being stacked vertically, and strain gauges 8 being disposed on the outer wall of each central cell 7 of the geocell 6, all of which are electrically connected to the data acquisition component.

[0029] This invention forms a model specimen 4 by stacking multiple geocells 6 one on top of the other, applies pressure to the model specimen 4 by a pressure application component, and monitors and records the parameters in real time during the test by a data acquisition component. This invention can accurately simulate and measure the stress-strain characteristics under the multi-cell interaction mechanism, providing important experimental basis and technical support for revealing the collaborative working mechanism of reinforced structures and improving the design theory of geocells 6.

[0030] The design was further optimized, and the pressure application component includes a reaction frame 1, with a pressure unit installed at the top end of the reaction frame 1 facing the geocell 6. The pressure unit adopts an electro-hydraulic servo dynamic and static testing machine system, which can meet the static and quasi-static testing requirements of large deformation components.

[0031] The scheme was further optimized so that the central axis of the loading head 2 of the pressurization unit and the central axis of the geocell 6 are on the same central axis.

[0032] The scheme was further optimized so that the central axis of geocell 6 and the central axes of the two bearing plates 3 are on the same central axis.

[0033] The central axis of multiple geocells 6, the central axis of the loading head 2, and the central axis of the two bearing plates 3 are all on the same central axis.

[0034] Reference Figures 8 to 10 To ensure that the central axes of the multiple geocells 6 and the two bearing plates 3 are aligned with the central axis of the loading head 2, adjustment components are provided on both sides of the sample assembly. Two adjustment components are symmetrically arranged on the inner walls of opposite sides of the reaction frame 1. Each adjustment component includes a support plate 10 fixedly connected to the inner wall of the reaction frame 1. A first movable plate 12 for adjusting the position of the bearing plate 3 is provided at the end of the support plate 10 facing away from the reaction frame 1. The support plate 10 and the first movable plate 12 are connected by multiple first hydraulic cylinders 11. The first movable plate 12 has a first clamping part for adjusting the position of the bearing plate 3. A second movable plate 14 for adjusting the position of the geocells 6 is provided at the end of the first movable plate 12 facing away from the first hydraulic cylinders 11. The first movable plate 12 and the second movable plate 14 are connected by multiple second hydraulic cylinders 13. The second movable plate 14 has a second clamping part for adjusting the position of the geocells 6.

[0035] The first clamping part includes symmetrically arranged first fixing blocks 121. The first fixing blocks 121 are fixedly connected to the side of the first movable plate 12 facing the support plate 10. A first drive shaft 123 is rotatably connected between the two first fixing blocks 121. The first drive shaft 123 passes through one end of either first fixing block 121 and is connected to a first motor 122. The first motor 122 is fixedly connected to the first fixing block 121. A first bevel gear 124 is sleeved on the first drive shaft 123. The first bevel gear 124 is keyed to the first drive shaft 123. The first bevel gear 124 meshes with a second bevel gear 125. The second bevel gear 125 is rotatably connected to the first movable plate 12. The second bevel gear 125 meshes with two third bevel gears 126. The two third bevel gears 126 are symmetrically arranged. The ends of the two third bevel gears 126 that are opposite to each other are respectively transmitted through the second drive shaft 127. A fourth bevel gear 128 is dynamically connected, and the fourth bevel gear 128 meshes with a fifth bevel gear 129. The fifth bevel gear 129 is rotatably connected to the first movable plate 12. The fifth bevel gear 129 meshes with two sixth bevel gears 130. The ends of the two sixth bevel gears 130 that are opposite to each other are respectively connected to a first lead screw 131. The end of the first lead screw 131 away from the sixth bevel gear 130 is rotatably connected to a second fixed block 135. The second fixed block 135 is fixedly connected to the first movable plate 12. The first lead screw 131 is threadedly connected to a first slider 133. The first slider 133 is slidably connected to a first slide groove 132. The first slide groove 132 is opened on the first movable plate 12. The end of the first slider 133 that extends out of the first slide groove 132 is fixedly connected to a first push plate 134. The first push plate 134 is set on the side of the first movable plate 12 facing the second movable plate 14.

[0036] Limiting blocks are rotatably connected to the end of the second drive shaft 127 near the fourth bevel gear 128 and the end of the first lead screw 131 near the sixth bevel gear 130. The limiting blocks are fixedly connected to the first movable plate 12.

[0037] The second clamping part includes symmetrically arranged third fixing blocks 141. The third fixing blocks 141 are fixedly connected to the side of the second movable plate 14 facing the first movable plate 12. A second lead screw 143 is rotatably connected between the two third fixing blocks 141. A second motor 142 is driven to one end of the second lead screw 143 that passes through the third fixing blocks 141. The second motor 142 is fixedly connected to the third fixing blocks 141. Two second sliders 145 are threadedly connected to the second lead screw 143. A second slide groove 144 is slidably connected to the second sliders 145. The second slide groove 144 is opened on the second movable plate 14. A second push plate 146 is fixedly connected to one end of the second slider 145 that extends out of the second slide groove 144. The second push plate 146 is located on the side of the second movable plate 14 facing the geocell 6.

[0038] The second lead screw 143 is a bidirectional lead screw, which allows the two second sliders 145 on the second lead screw 143 to move closer to or further away from each other.

[0039] First, the first hydraulic cylinder 11 drives the two first movable plates 12 to move closer together, causing the two first movable plates 12 to move the two bearing plates 3 to the center position. Then, the first motor 122 drives the first transmission shaft 123 to rotate, the first transmission shaft 123 drives the first bevel gear 124 to rotate, the first bevel gear 124 drives the second bevel gear 125 to rotate, the second bevel gear 125 drives the two third bevel gears 126 to rotate synchronously, the third bevel gear 126 drives the fourth bevel gear 128 to rotate via the second transmission shaft 127, the fourth bevel gear 128 drives the fifth bevel gear 129 to rotate, the fifth bevel gear 129 drives the two sixth bevel gears 130 to rotate synchronously, the sixth bevel gears 130 drive the first lead screw 131 to rotate, the first lead screw 131 drives the first slider 133 to move along the first slide groove 132, and the two first sliders 133 move closer together, causing the two first push plates 134 to move closer together, that is, through the first... A movable plate 12 and multiple first push plates 134 align the central axis of the bearing plate 3 with the central axis of the loading head 2 of the pressurizing section. Then, a second hydraulic cylinder 13 drives two second movable plates 14 to move closer together, causing the two second movable plates 14 to move the geocell 6 to the center position. Next, a second motor 142 drives a second lead screw 143 to rotate, which in turn drives two second sliders 145 to move closer together. The second sliders 145 then drive second push plates 146 to move, causing multiple second push plates 146 to move the geocell 6. Thus, the central axis of the geocell 6 is aligned with the central axis of the loading head 2 of the pressurizing section through the second movable plates 14 and multiple second push plates 146. Finally, the first movable plate 12, second movable plate 14, first push plate 134, and second push plate 146 are moved away from the bearing plate 3 and the geocell 6, allowing the geocell 6 to be tested.

[0040] To further optimize the design, handles 9 are fixedly connected to both sides of the top surface of the support plate 3, with the two handles 9 positioned opposite each other. The handles facilitate the handling of the support plate 3.

[0041] The bearing plate 3 is made of two Q345 steel plates of specific dimensions. During the loading process, the maximum deformation of the bearing plate 3 is less than 0.005 mm, which is only 0.05% of the plate thickness. The Von Mises stress is much lower than the yield strength of the steel, which can ensure that the stiffness and stability of the bearing plate 3 meet the requirements during the test. This allows the load of the loading head 2 to be uniformly transferred to the model specimen 4.

[0042] The design was further optimized, and the geocell 6 was arranged in an equilateral quadrilateral shape.

[0043] Based on in-depth research on the stress characteristics of multi-grid geocell structures and the reinforcement-soil interaction mechanism under load, this invention, in the design of model specimen 4, draws on the specimen size principle of classical triaxial test of soil and rock, and determines the height-to-width ratio of the multi-grid reinforced specimen to be 2:1, so as to ensure the rationality of stress distribution and the comparability of test results.

[0044] Meanwhile, to avoid warping instability caused by excessive cell height and its impact on test accuracy, the height of the geocell 6 is set to 50mm. This size also conforms to the commonly used specifications in current engineering practice, taking into account both test feasibility and engineering representativeness.

[0045] To further optimize the design, strain gauges 8 are also installed on the side walls of the adjacent side grids of the center grid 7.

[0046] The scheme was further optimized, and the acquisition components include a data acquisition instrument 5, which is connected to the strain gauge 8 via a cable.

[0047] To further optimize the design, the data acquisition device 5 is placed on one side of the reaction frame 1.

[0048] Reference Figures 1 to 30 A method for testing the mechanical properties of geocells based on multi-cell interaction mechanisms.

[0049] The experiment will be conducted using the testing device of this invention; its core advantage lies in its ability to realistically simulate and accurately measure the collaborative working mechanism between multiple grid cells; through this innovative platform, the aim is to systematically reveal the stress diffusion law, strain development mode and overall bearing deformation characteristics of geocell reinforced structures under load under different grid types and sizes, providing key experimental basis for improving its design theory.

[0050] Reference Figures 11 to 12 , Figure 11 The bearing capacity-settlement relationship curve is shown for a grid with a side length of 125mm. Figure 12 This is a curve showing the relationship between bearing capacity and settlement for a side length of 150mm; (The sentence is incomplete and requires more context to translate accurately.) Figures 11 to 12 The load-settlement relationship curves of geocell reinforced structures with three different grid types and sizes (1×1, 2×2, and 3×3) are presented respectively. The trends of the curves show that all types of reinforced structures exhibit similar mechanical response characteristics: the initial stage is the compaction stage, where settlement increases approximately linearly with increasing load, and the load-settlement curve maintains a straight upward trend; as settlement further increases, the curve gradually deviates from the linear relationship and bends downward, entering the nonlinear development stage; in this stage, the rate of settlement increase gradually exceeds the rate of load increase, indicating an accelerating trend of settlement development.

[0051] It is worth noting that the results of the parallel experiments are in high agreement with the main experimental data, and the curves have good overlap. This verifies the reliability of the experimental method and also shows that the experimental results have high repeatability.

[0052] In geocell reinforced structures, when subjected to axial loads, the geocells exert lateral compressive force on the internal fill soil, while simultaneously providing circumferential restraint on the fill soil due to their own strength, thus forming an effective reinforcement mechanism. In-depth research on the lateral deformation law of geocells during loading is of great theoretical significance and engineering value for revealing the multi-cell reinforcement mechanism, identifying safe bearing capacity, and optimizing structural design.

[0053] Reference Figures 13 to 16 , Figure 13 This is a schematic diagram of the transverse strain-bearing capacity relationship curve for a 1×1 type mesh. Figure 14 This is a graph showing the transverse strain-bearing capacity relationship of a 2×2 grid. Figure 15 This is a graph showing the transverse strain-bearing capacity relationship of a 3×3 grid. Figure 16 The transverse strain-bearing capacity relationship curve is shown for a 3×3 intermediate layer mesh (125mm); through... Figures 13 to 16 The results show the response relationship between different grid types and the development law of transverse strain and bearing capacity of geocells under the condition of 125mm cell side length. The results obtained in this experiment are in good agreement with the parallel test data, and the trends of the two are highly consistent. The errors of the key numerical points are all within the acceptable range.

[0054] This fully demonstrates that the experimental process has good repeatability and the obtained data has high reliability.

[0055] In addition, refer to Figures 17 to 19 , Figure 17 The vertical strain pattern is shown for a 1×1 grid. Figure 18 The vertical strain pattern is shown for a 2×2 grid. Figure 19 The vertical strain pattern of a 3×3 grid; through Figures 17 to 19 The distribution of vertical geocell strain in reinforced specimens under different mesh types and sizes is shown. Figures 17 to 19 It can be observed that as the number of reinforced sample layers increases, the strain value of the geocell in the central region shows a significant increasing trend, reaching a peak in the middle layer; subsequently, the strain value gradually decreases as the number of layers continues to increase, and the overall structure exhibits a symmetrical distribution characteristic with the middle layer as the axis of symmetry; this pattern indicates that the strain distribution of the geocell is significantly affected by the structural symmetry, and the middle layer, as the area with the greatest stress, has the most significant strain response.

[0056] Furthermore, comparing the curves under different mesh types and sizes reveals that changes in mesh parameters have little impact on the symmetry characteristics of the strain distribution, but significantly affect the size and distribution range of the strain peak.

[0057] Further analysis Figures 17 to 19 The experimental data shows that the results of parallel experiments and model experiments are highly consistent (within ±5% of the error range). This good agreement verifies the reliability and repeatability of the experimental data.

[0058] When examining the effect of mesh size, it was found that the transverse strain produced by the mesh with a side length of 150 mm was generally higher than that of the mesh with a side length of 125 mm.

[0059] This phenomenon suggests that increasing the grid size may weaken the lateral restraint of the geocell on the internal soil, thus making it more prone to lateral deformation under the same load conditions.

[0060] At the same time, by Figure 19 It can be seen that the transverse strain variation trend of the geocell in the internal region is basically consistent with that in the central region, but the strain amplitude is relatively small. This may be due to the gradient difference in stress distribution caused by the boundary constraint effect. Even under the overall coordinated deformation mode, there is still an obvious stress redistribution and deformation coordination mechanism inside the geocell reinforcement. Different regions exhibit layered mechanical response characteristics due to the difference in constraint conditions. The specific structure of the model specimen 4 of this invention can be effectively obtained.

[0061] Addressing the core challenge of the complex and difficult-to-accurate measurement of the interaction mechanism between multi-grid geocell units, this invention uses a data acquisition component to capture key parameters such as strain development in geocells, soil deformation, and interfacial stress redistribution in real time.

[0062] Compared with existing testing methods, this invention significantly improves the ability to quantify the strength field and deformation field of multi-grid stiffened systems, especially to more accurately describe their nonlinear mechanical behavior. It has obvious advantages in revealing the multi-grid collaborative working mechanism under small deformation stage and complex stress path conditions, and can effectively reduce the simplification error in traditional theoretical analysis.

[0063] Reference Figures 3 to 7 The geocell 6 strain monitoring system adopts a multi-level, zoned deformation monitoring scheme with bonded strain gauges 8, specifically as follows: (1) For the key stress area of ​​the geocell 6 in the middle layer of the model specimen 4, a key monitoring strategy is adopted. Strain gauges 8 are arranged at the center of the strip of the geocell 6 to obtain the strain field distribution of the main stress area.

[0064] (2) For the monitoring areas of the top and bottom layers of model sample 4, an optimized monitoring scheme is implemented. In addition to arranging measuring points in the center of the middle grid strip, auxiliary measuring points are also arranged inside at twice the grid spacing to form a cross monitoring network.

[0065] (3) In order to investigate the strain transmission law along the model height, monitoring points were added to the middle grid strip of the interval layer.

[0066] The specific layout and implementation are as follows: Taking a 3×3 grid geocell reinforced sand sample as an example, this sample consists of 15 layers of geocell reinforced sand stacked vertically (refer to...). Figure 3 ).

[0067] The strain gauges are arranged using a layered, focused monitoring scheme: (1) Full coverage monitoring was implemented at the intermediate position in the critical layer (8th layer), and strain gauges were attached to the outer layer at intervals, for a total of 14 measuring points, numbered 1#-14# (refer to Figure 7 ).

[0068] (2) To investigate the boundary effect, eight strain gauges were symmetrically arranged on the top layer (layer 1) and bottom layer (layer 15) of model specimen 4, numbered 1#-8# (refer to...). Figure 6 ).

[0069] (3) Key monitoring points are set up at the center of the intermediate transition layers (layers 3, 5, 7, 9, 11 and 13), with 4 strain gauges arranged on each layer, numbered 1#-4# (refer to Figure 5 ).

[0070] This multi-layered strain monitoring network design can not only focus on the deformation characteristics of the middle part of the sample, but also reflect the deformation gradient of the entire sample through the strain data of the key layer, thus providing comprehensive experimental data support for analyzing the mechanical response of geocell reinforced structures.

[0071] Reference Figures 20 to 22Currently, the literature (Banerjee S, Manna B, Shahu TJ. Geocell as a Promising Reinforcement Technique for Road Pavement: A State of the Art[J]. Indian Geotechnical Journal, 2023, 54(4): 1644-1665) and the literature (Zhao Y.; Lu Z.; Liu J., et al. Compaction-induced prestressing effect of geocell reinforcement[J]. Geosynthetics International, 2024, 1-48) believe that the reinforcement effect of geocells is mainly circumferential constraint; the literature (Bathurst RJ, Karpurapu R. Large-scale triaxial compression testing of geocell-reinforced granular soils[J]. Geotechnical Testing Journal, 1993, 16(3): 296-303) and the literature (Rajagopal K, Krishnaswamy NR, Madhavi) believe that the reinforcement effect of geocells is mainly circumferential constraint. The research results of Latha G. Behavior of sand confined with single and multiple geocells[J]. Geotextiles and Geomembranes, 1999, 17(3): 171-184) reveal that the circumferential action of geocell reinforcement will form a confining pressure on the fill material. This improves the strength of the reinforced soil. Based on the lateral confinement effect of geocell reinforcement, and using the tension theory of thin-walled cylinders (Henkel, DJ, Gilbert, GC. The effect of rubbermembranes on the measured triaxial compression strength of clay samples. Géotechnique, 1952, 3, 20-29), the confinement effect of geocells on the soil can be quantified, and the resulting confining pressure can be determined accordingly. It can be determined by the following formula: (Equation 1) In Equation 1, The axial strain of the specimen; To achieve tensile strain The secant modulus of the geocell strip corresponding to the time can be determined by tensile testing of the geocell strip; For the axial strain of the specimen The circumferential strain at time t can be calculated using the equivalent volume method before and after loading, and its expression is: (Equation 2) In Equation 1 The specimen reaches axial strain At that time, the deformed diameter of the geocell mesh is equal to the original diameter of the geocell mesh. The relationship can be expressed by the following formula: (Equation 3) It is worth noting that if square, rhomboid, or other non-circular meshes are encountered in design calculations, the calculation formula for circular meshes cannot be directly applied. In this case, the equivalent circular diameter of the non-circular mesh can be solved using the principle of area equivalence. , S This represents the area of ​​the non-circular grid.

[0072] Furthermore, in geotechnical engineering, incremental relationships are commonly used to represent the stress-strain constitutive relationship of soil. Therefore, Equation 1 is also extended to the following incremental form: (Equation 4) In Equation 4, Let be the tangential modulus of the geocell; assuming the deformation in the circumferential direction of the sample is uniform, then It can be approximated as .

[0073] Reference Figures 23 to 24 Geocell reinforced structures not only rely on the lateral constraint effect of individual grids, but also form a more robust overall load-bearing system through a collaborative working mechanism among multiple grid units. Under axial loads, the interconnected geocell units form an integral composite reinforcement layer through a three-dimensional spatial grid structure, which possesses both high compressive stiffness and tensile strength. This unique structural characteristic produces two significant effects: firstly, the multiple grid units act as a net in the geocell reinforced sand structure, generating an upward overall lifting effect through collaborative deformation, thereby significantly improving the structural bearing capacity and effectively dispersing axial loads; secondly, the collaborative deformation of multiple grids transforms the reinforced structure into a load-bearing system with flexible raft characteristics.

[0074] This flexible raft structure exhibits excellent comprehensive performance in bending, shear, and compression. Its mechanism of action is manifested in the following ways: firstly, it absorbs and dissipates part of the axial load through structural deformation; secondly, it utilizes large-area contact characteristics to achieve three-dimensional load diffusion and stress redistribution; and finally, it significantly improves the overall strength and bearing capacity of the reinforced sand structure by modifying the stress and strain fields of the reinforced structure. This multi-scale, multi-dimensional reinforcement mechanism, working together, gives geocell reinforced structures significant technical advantages in the field of geotechnical engineering.

[0075] Analysis of the strain field measurements of the geocell strips reveals a significant gradient in the horizontal strain distribution of the internal grid regions of the model structure: the strain value of the central strip is significantly higher than that of the outer elements, and this difference is more pronounced under larger axial strain conditions. Analysis of the multi-grid mechanism of the geocell reinforcement reveals that this strain distribution characteristic stems primarily from two mechanisms: firstly, the mesh effect generated by the multi-grid structure effectively disperses concentrated stress; secondly, the resulting reinforced flexible raft effect enhances the overall coordinated deformation capacity and stress diffusion range, and the synergistic work of the multi-grid under load improves the load-bearing capacity of the reinforced structure. Furthermore, because the central strip is located at the core of the stress transmission path, it bears and shares the largest strain. As the distance from the load center increases, the strain energy is gradually diffused and consumed through the membrane effect of the geocell wall and its interaction with the fill material, resulting in the lowest strain value in the outer strips. This non-uniform strain distribution pattern poses a crucial challenge to classical reinforced soil design theory: if the maximum strain in the central region is used as the benchmark, it essentially employs the "limit state design" approach. Conversely, using the minimum strain or some average strain in the outer region as the benchmark is closer to the concept of "system collaborative design." Therefore, the following in-depth discussion addresses the issue of selecting the strain benchmark for geocells.

[0076] To quantitatively evaluate the difference in contribution of mesh strips to the strength of reinforced structures with different mesh numbers, this invention introduces an external strip contribution coefficient. As an evaluation metric, its expression is defined as follows: (Equation 5) In Equation 5, N p The number of meshes around the reinforced structure; f p It is the proportion factor of the external strips to the total number of strips in the reinforced structure.

[0077] Taking the 1×1, 2×2, and 3×3 mesh types in this invention as examples, and extending the 6×6 mesh to include parameter pairings... N p and f pThe factors represented are presented in detail.

[0078] Reference Figures 25 to 28 The contribution relationship of geocell strips to the strength of multi-grid reinforced structures was investigated, and the contribution relationship was extended to 4×4, 5×5, 6×6, etc. through analogy. n × n The generalized multigrid model is used. Finally, the contribution coefficients of the external stripes are obtained. parameters , scaling factor Furthermore, to quantify the relationship between the mechanical properties of multi-grid structures and single-grid structures, this invention proposes a multi-grid effect factor. E f The concept of is expressed as: (Equation 6) In Equation 6, The multi-grid effect intensity enhancement factor is defined as the extreme value of the horizontal strain in a multi-grid system under the same axial strain conditions. ) and the extreme values ​​of horizontal strain in a single grid ( The ratio of ), i.e. .

[0079] To establish a quantitative prediction model for strip strain in multi-grid geocell reinforced structures, this invention integrates multi-grid effect factors. Based on the horizontal strain test data of the geocell reinforced structure obtained in this invention, empirical formulas were fitted using nonlinear regression analysis. Based on the strain gradient distribution characteristics and the mesh synergistic mechanism, a multi-grid horizontal strain model was proposed. The expression is: (Equation 7) In Equation 7: , and These are material property parameters, determined through fitting experimental data.

[0080] Verification of the specific structure of model specimen 4: This invention uses three typical grid types, namely 1×1 single cell, 2×2 and 3×3, and two cell sizes, namely 125mm and 150mm, as the core variable parameters for testing; the height of geocell 6 is uniformly 50mm, which is commonly used in engineering, under all working conditions. The detailed test plan is shown in Table 1 Experimental Plan.

[0081] Table 1 Test Scheme

[0082] In terms of specimen design, the principle of similarity in geotechnical model tests was strictly followed, and a fixed height-to-width ratio of 2:1 was set. Based on this ratio, by precisely adjusting the number of stacking layers of geocell 6, geometrically similar test specimens were constructed for different grid sizes, thereby ensuring the comparability and scientific validity of test results under different working conditions.

[0083] Reference Figures 29 to 30 By comparing the calculation results of Equation 7 with the experimental data, it can be found that the calculation results of the constructed multi-grid geocell reinforced structure strip strain prediction model have a high degree of agreement with the experimental results. The curves of both have consistent trends, and the strain numerical errors at key feature points are all within 3%, with a correlation coefficient R0. 2 The model achieved a value of over 0.97. This excellent fit fully validates the reliability of the model, demonstrating its ability to accurately characterize the distribution and development characteristics of strip strain in multi-grid geocell reinforced structures under axial stress conditions, thus providing a valid theoretical basis for engineering design and performance evaluation.

[0084] It is noteworthy that among various grid types, the horizontal strain distribution of the 1×1 geocell is closest to the theoretical prediction, and its magnitude is greater than the horizontal strain in the central region of multi-grid configurations such as 2×2 and 3×3, and even significantly greater than the strain level in the model's edge region. This phenomenon reveals the significant influence of grid configuration on the stress diffusion capacity and deformation mode of the reinforced body. Due to the high element independence, the stress concentration effect is more pronounced in the 1×1 configuration, leading to a significant increase in its horizontal strain; while the multi-grid configuration achieves effective stress diffusion through the collaborative work of adjacent elements, thereby reducing the strain level in the central region. Under the multi-grid configuration, the traditional uniform strain assumption is no longer applicable, and the spatial non-uniformity of strain distribution must be considered.

[0085] To establish horizontal strain suitable for multi-grid configurations The present invention proposes using the average value of the test results for the central and peripheral grids as the representative horizontal strain of the geocell-reinforced multigrid model. This approach considers both the spatial variability of strain distribution in the multigrid system and eliminates the influence of local outliers through statistical methods, thereby improving the representativeness and engineering applicability of strain values ​​while ensuring computational simplicity.

[0086] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0087] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for testing the mechanical properties of geocells based on a multi-cell interaction mechanism, and a geocell mechanical property testing device based on a multi-cell interaction mechanism, characterized in that: It includes a pressure application component, a sample assembly is disposed below the pressure application end of the pressure application component, the pressure application component is used to apply pressure to the sample assembly, and the sample assembly is electrically connected to a data acquisition component, the data acquisition component is used to monitor and record parameters in real time during the test process; The sample assembly includes a model sample (4), and a support plate (3) is provided above and below the model sample (4). The model specimen (4) includes multiple geocells (6), which are stacked one on top of the other. Each outer wall of the central cell (7) of the geocell (6) is provided with a strain gauge (8), and the strain gauges (8) are electrically connected to the acquisition component. The strain gauges (8) are also respectively disposed on the side walls of the side grids adjacent to the central grid (7); To quantify the relationship between the mechanical properties of multi-grid structures and single-grid structures, a multi-grid effect factor is proposed. E f The concept of is expressed as: In the formula, The multi-grid effect intensity enhancement factor is defined as the extreme value of the horizontal strain in a multi-grid system under the same axial strain conditions. ) and the extreme values ​​of horizontal strain in a single grid ( The ratio of ), i.e. ; To establish a quantitative prediction model for strip strain in multi-grid geocell reinforced structures, multi-grid effect factors were integrated. The acquisition components are used to monitor and record parameters during the experiment in real time, and empirical formulas are fitted through nonlinear regression analysis. Based on the strain gradient distribution characteristics and the mesh synergy mechanism, a multi-grid horizontal strain model is proposed. The expression is: In the formula: , and These are material property parameters, determined through fitting experimental data.

2. The method for testing the mechanical properties of geocells based on multi-cell interaction mechanisms according to claim 1, characterized in that: The pressure application assembly includes a reaction frame (1), and a pressure application part is installed on the top end of the reaction frame (1) facing the geocell (6).

3. The method for testing the mechanical properties of geocells based on multi-cell interaction mechanisms according to claim 2, characterized in that: The central axis of the loading head (2) of the pressurizing part is on the same central axis as the central axis of the geocell (6).

4. The method for testing the mechanical properties of geocells based on multi-cell interaction mechanisms according to claim 2, characterized in that: The central axis of the geocell (6) is on the same central axis as the central axes of the two bearing plates (3).

5. The method for testing the mechanical properties of geocells based on multi-cell interaction mechanisms according to claim 1, characterized in that: Handles (9) are fixedly connected to both sides of the top surface of the bearing plate (3), and the two handles (9) are arranged opposite to each other.

6. The method for testing the mechanical properties of geocells based on multi-cell interaction mechanisms according to claim 1, characterized in that: The geocells (6) are arranged in an equilateral quadrilateral shape.

7. The method for testing the mechanical properties of geocells based on multi-cell interaction mechanisms according to claim 2, characterized in that: The acquisition component includes a data acquisition instrument (5), which is connected to the strain gauge (8) via a cable.

8. The method for testing the mechanical properties of geocells based on the multi-cell interaction mechanism according to claim 7, characterized in that: The data acquisition device (5) is located on one side of the reaction frame (1).

Images