Rigidity coordination test structure and test method of active unloading type gravel reinforced structure

Abstract

The invention relates to the technical field of tunnel structure testing, in particular to a rigidity coordination testing structure and method for an active unloading type gravel reinforcing structure. Comprising two supports, a gabion is jointly arranged on the two supports, a plurality of opposite-pull connecting rod assemblies are arranged on the gabion, a strain gauge is arranged on each opposite-pull connecting rod assembly, a static strain gauge is connected to each strain gauge, two I-shaped beams are arranged on the upper surface of the gabion, a counter-force frame is arranged on an experiment platform, and the counter-force frame is connected with the gabion. Jacks are arranged on the upper surfaces of the two I-shaped beams and located between the counter-force frame and the I-shaped beams, and a non-contact full-field strain measurement system for measuring displacement data of the lower edge of the gabion is arranged on the experiment platform. The working state of the active unloading type macadam reinforcing structure in the tunnel can be simulated indoors, the stress and unloading mechanism of the active unloading type macadam reinforcing structure in the tunnel can be truly restored indoors, and the overall rigidity evolution characteristics of the active unloading type macadam reinforcing structure can be reflected.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of tunnel structure testing, and particularly relates to a stiffness coordination test structure and test method for an active unloading type rubble reinforcement structure. BACKGROUND

[0002] During tunnel excavation, stress release caused by unloading of surrounding rock will cause deformation and crack development of the surrounding rock, resulting in long-term complex stress environment of the lining structure; in order to reduce the influence of pressure concentration of surrounding rock on the tunnel support structure, active unloading structures have been gradually proposed and applied in the engineering field.

[0003] However, the existing active unloading structure has less application in tunnel engineering, and the rubble filling structure similar to gabion stone cage type has not been fully studied, and the unloading mechanism and overall stiffness characteristics of the structure lack systematic test verification.

[0004] On the other hand, existing researches often focus on the stress characteristics of local components, and there are few studies on measuring the overall stiffness of the structure and its change law during loading, which to some extent restricts the popularization and optimization design of related structures in tunnel engineering.

[0005] Therefore, there is an urgent need for a stiffness coordination test structure and test method for an active unloading type rubble reinforcement structure, which can truly reflect the overall stiffness evolution characteristics of the active unloading type rubble reinforcement structure, thereby providing a scientific basis for the reasonable design and application of such structures in tunnel engineering. SUMMARY

[0006] The present application aims to solve the above problems and provides a stiffness coordination test structure and test method for an active unloading type rubble reinforcement structure, which can simulate the working state of the active unloading type rubble reinforcement structure in a tunnel indoors, truly restore the stress and unloading mechanism of the active unloading type rubble reinforcement structure in a tunnel under indoor conditions, truly reflect the overall stiffness evolution characteristics of the active unloading type rubble reinforcement structure, and thereby provide a scientific basis for the reasonable design and application of such structures in tunnel engineering.

[0007] The present application solves the problem by adopting the following technical solution: The application discloses a rigidity coordination test structure of an active unloading type gravel reinforcing structure, which is arranged on an experimental platform and comprises two supports which are identical in structure and are arranged on the experimental platform in parallel to each other, a gabion is arranged on the two supports, a plurality of tension link assemblies are arranged on the gabion between the two supports, the tension link assemblies are arranged in the gabion in a penetrating mode and are arranged in a length direction of the gabion in a spaced mode, at least one strain gauge is arranged on each of the tension link assemblies and is arranged in the gabion, a static strain gauge is connected to the strain gauge, two I-beams are arranged on an upper surface of the gabion and are symmetrically arranged with the length of the gabion as a center line, a counterforce frame is arranged on the experimental platform and is located directly above the two I-beams, a jack is arranged on an upper surface of each of the two I-beams and is located between the counterforce frame and the I-beam, and a non-contact full-field strain measurement system is arranged on the experimental platform and is used for measuring displacement data of a lower edge of the gabion.

[0008] Preferably, the length of the gabion is greater than the distance between the two supports, and the two ends of the gabion extend out of the supports.

[0009] Preferably, the gabion comprises a metal mesh cage box, the metal mesh cage box is hollow and is filled with gravel.

[0010] Preferably, the gravel is stacked in a layer mode in a height direction in the metal mesh cage box.

[0011] Preferably, the tension link assembly comprises a tension link, the tension link penetrates the gabion in a penetrating mode, the two ends of the tension link extend out of the gabion, a fastening nut is threadedly connected to each of the two ends of the tension link, and the two fastening nuts are cooperatively used for fixing the tension link on the gabion.

[0012] Preferably, two strain gauges are arranged on the outer surface of the tension link, the two strain gauges are arranged in a spaced mode in a length direction of the tension link, the two strain gauges are arranged in the gabion, and the two strain gauges are connected to the static strain gauge.

[0013] Preferably, when the gabion is subjected to loads applied by the two jacks, displacement data of the gabion measured by the non-contact full-field strain measurement system and axial forces of the tension link measured by the static strain gauge are synchronously acquired, and the overall rigidity of the gabion is obtained by combining a simply supported beam deflection calculation formula.

[0014] Preferably, when the gabion is subjected to loads applied by the two jacks, the overall rigidity of the gabion changes with the change of a fastening force of the tension link assembly on the gabion.

[0015] Preferably, the overall rigidity of the gabion and the tightening force of the tensile link assembly applied to the gabion vary with the load received by the gabion.

[0016] A test method for testing the rigidity coordination of a self-unloading rubble reinforcement structure, comprising the following steps: S1. According to the length of the gabion, two supports are placed on the experimental platform, the gabion is placed on the two supports, and a plurality of tensile link assemblies are installed on the gabion between the two supports, so that the plurality of tensile link assemblies are sequentially spaced along the length direction of the gabion and penetrate the gabion, and then the tightening force of each tensile link assembly is sequentially applied according to the test specification; S2. Before the tensile link assembly is fixed on the gabion, strain gauges are pre-pasted on the tensile link, and when the tensile link assembly is fixed on the gabion, the strain gauges are connected to the static strain meter; S3. The non-contact full-field strain measurement system is placed on the experimental platform, and the non-contact full-field strain measurement system is adjusted according to the position of the lower edge of the gabion, so that the non-contact full-field strain measurement system corresponds to the position of the lower edge of the gabion; S4. Then, two I-beams are placed on the upper surface of the gabion, and the two I-beams are symmetrically arranged with the length division line of the gabion as the center line, and then the counterforce frame is placed on the experimental platform, and the two jacks are correspondingly placed between the counterforce frame and the two I-beams; S5. When the counterforce frame, the two jacks and the two I-beams jointly apply load to the gabion, the static strain meter and the non-contact full-field strain measurement system synchronously collect the axial force of the tensile link under the action of the load and the displacement data of the lower edge of the gabion; S6. When the displacement data of the lower edge of the gabion and the axial force of the tensile link under the action of the load are obtained, the displacement of the lower edge of the gabion is: Where P is the total load applied, a is the distance from the support point to the adjacent loading point, L is the support span, E is the elastic modulus, I is the cross-sectional moment of inertia, and δ is the lower edge displacement. Thus, the overall rigidity of the gabion is calculated.

[0017] Compared with the prior art, the technical scheme of the present application has the following outstanding features: The application can realize the change characteristics of the stiffness of the active unloading type rubble reinforcing structure in the unloading process in the simulated tunnel, can simulate the working state of the active unloading type rubble reinforcing structure in the tunnel, realizes the stress in the unloading process by using the loading experiment method, and then realizes the stiffness change law research, thereby improving the scientificity and reliability of the tunnel supporting structure design and optimization, can truly restore the stress and unloading mechanism of the active unloading type rubble reinforcing structure in the tunnel under the indoor condition, can truly reflect the overall stiffness evolution characteristics of the active unloading type rubble reinforcing structure, has the advantages of simple structure, convenient operation, intuitive parameter monitoring and the like, significantly improves the scientificity, authenticity and reliability of the test results, and thereby provides a scientific basis for the reasonable design and application of the structure in the tunnel engineering. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a schematic diagram of the front view structure of the application; Figure 2 is a schematic diagram of the elevation structure of the application; Figure 3 is a schematic diagram of the front view structure of the tension link; Figure 4 is a schematic diagram of the test process of the application Figure 1 ; Figure 5 is a schematic diagram of the test process of the application Figure 2 ; Figure 6 is a schematic diagram of the test process of the application Figure 3 ; Figure 7 is a schematic diagram of the test process of the application Figure 4 ; In the drawing: 1, support; 2, metal mesh cage box; 3, rubble; 4, tension link; 5, fastening nut; 6, I-beam; 7, strain gauge; 8, jack; 9, gabion; 10, tension link assembly. DETAILED DESCRIPTION

[0019] The application will be more helpful for the public to understand the application through the following description of the embodiments, but the specific embodiments given by the applicant should not be regarded as the limitation of the technical scheme of the application, and any change of the definition of the components or technical features and / or formal but not substantial change of the overall structure should be regarded as the protection scope defined by the technical scheme of the application.

[0020] Referring to Figures 1 to 7 , the technical scheme of the application is as follows: The application discloses a rigidity coordination test structure of an active unloading type rubble reinforcing structure, which is arranged on an experimental platform and comprises two supports 1 which are identical in structure, are steel supports 1 and have plane upper surfaces and lower surfaces, is arranged on the experimental platform in a spaced mode and is parallel to each other, has a gabion 9 arranged on the two supports 1 in common, has a length greater than the interval between the two supports 1 and has two end portions extending out of the supports 1, has a plurality of tension link assemblies 10 arranged on the gabion 9 between the two supports 1, is penetrated through the gabion 9 in an up-down mode and is arranged in a spaced mode along the length direction of the gabion 9 in sequence, wherein the tension link assembly 10 is a main force transmission component and comprises a tension link 4, the tension link 4 is penetrated through the gabion 9 in an up-down mode, the two end portions of the tension link 4 extend out of the gabion 9 in an outward mode, the two end portions of the tension link 4 are provided with threaded fastening nuts 5 which are connected in a threaded mode, the two fastening nuts 5 are arranged in a cooperative mode to fix the tension link 4 on the gabion 9, the tension link 4 is made of an HRB400 steel bar and an A18 mm length 160 mm threaded steel bar, the fastening nut 5 is made of an M18 and has a length of 20 mm, the tension link assembly 10 is used for reinforcing the gabion 9 into a beam by adjusting the fastening force of the nut, the rigidity of the gabion 9 can be controlled by applying the fastening force, namely the prestress, through a bolt, the relationship between different prestresses and elastic moduli is constructed, two strain gauges 7 are arranged on the tension link of each tension link assembly 10, the two strain gauges 7 are arranged on the outer surface of the tension link 4 in a spaced mode along the length direction of the tension link 4, the two strain gauges 7 are arranged in the interior of the gabion 9 and are connected with a static strain meter, so that the axial force, namely the prestress, of the tension link 4 under the action of a load is measured through the cooperation of the static strain meter and the strain gauges 7, two I-shaped beams 6 are arranged on the upper surface of the gabion 9 and are arranged in a symmetrical mode with the length division line of the gabion 9 as a center line, a counterforce frame is arranged on the experimental platform and is located directly above the two I-shaped beams 6, two jacks 8 are arranged on the upper surfaces of the two I-shaped beams 6 and are located between the counterforce frame and the I-shaped beams 6, the counterforce frame, the two jacks 8 and the two I-shaped beams 6 are arranged in a cooperative mode to apply a load to the gabion 9, so that the rubble 3 and the tension link generate a force response, the working state of the active unloading type rubble reinforcing structure of a tunnel under the action of a load is simulated, the load applied to the gabion 9 can be changed to provide different unloading states, the simulation of the rigidity coordination of the structure is realized, so that the influence of the unloading degree difference on the rigidity coordination characteristic of the structure in an actual tunnel project is reproduced, and a non-contact full-field strain measurement system is arranged on the experimental platform and corresponds to the lower edge position of the gabion 9, so as to be used for measuring the lower edge displacement data of the gabion 9.Thus, the displacement data of the lower edge of the gabion 9 obtained by measurement is used to calculate the overall stiffness of the structure, the non-contact measurement of the deformation of the structure is realized, the stress-displacement curve of the structure is obtained, and the accuracy and reliability of data acquisition are ensured. In addition, the structure is arranged to simulate the stiffness change characteristics of the active unloading gravel 3 reinforced structure in the tunnel.

[0021] The gabion 9 comprises a metal mesh cage box 2 which is formed by welding high-strength metal wires and has sufficient overall stiffness. The metal mesh cage box 2 is 600 mm long, 100 mm wide and 100 mm high, is hollow inside and filled with gravel 3. The gravel 3 is stacked in layers along the height direction in the metal mesh cage box 2. The gravel 3 is filled in layers during the filling process, and each layer of gravel 3 is slightly vibrated after being placed to avoid excessive local voids that affect the stress uniformity. The particle size of the gravel 3 is controlled within a specified range, such as 20-40 mm, to ensure that it has good compressibility and water permeability, can release part of the external force at the initial stage of loading, and reduce stress concentration. The metal mesh cage box 2 plays a role in stabilizing the gravel 3 body and ensuring the integrity and controllable deformation performance of the overall structure of the gabion 9. The structure of the gabion 9 is arranged to realize the active unloading function.

[0022] When the gabion 9 is subjected to the load applied by the two jacks 8, the displacement data of the gabion 9 measured by the non-contact full-field strain measurement system and the axial force of the tension link 4 measured by the static strain gauge are obtained synchronously, and the overall stiffness of the gabion 9 is obtained by combining the deflection calculation formula of the simply supported beam, so as to reveal the stiffness coordination characteristics of the active unloading gravel 3 reinforced structure, and further analyze the stiffness coordination characteristics of the active unloading gravel 3 reinforced structure. In addition, by calculating the stiffness of the entire structure, the bearing capacity and coordination performance of the structure under different loads and prestresses can be judged.

[0023] When the gabion 9 is subjected to the load applied by the two jacks 8, the overall stiffness of the gabion 9 changes with the change of the fastening force of the tension link assembly 10 on the gabion 9. While adjusting the fastening force of the tension link assembly 10, the change of the axial force in the tension link 4, i.e. the change of the prestress in the entire structure, can construct the relationship between different prestresses and elastic moduli.

[0024] The overall stiffness of the gabion 9 and the fastening force of the tension link assembly 10 on the gabion 9 change with the change of the load on the gabion 9, so as to simulate different prestresses and unloading states, and further reproduce the influence of the release of surrounding rock pressure on the stiffness of the structure in actual tunnel engineering.

[0025] It should be noted that: the experimental platform, counter-force frame, static strain gauge and non-contact full-field strain measurement system are not indicated in the drawings; both I-beams 6 are made of steel and integrated; the width of gabion 9 is consistent with the width of two supports 1 and the width of two I-beams 6; in addition, the specifications, tonnage of two jacks 8 and the specifications of the counter-force frame are changed with the change of the load applied to the gabion 9; In addition, the static strain gauge adopts CM1J type static strain gauge, which adopts digital keyboard function, and the selection of measuring point and the setting of strain gauge 7 sensitivity are more convenient, and a special mathematical model is used to directly display the force value and displacement value, providing a simple and easy-to-use way for various measurements; the built-in non-volatile memory can store and play back 99 levels of data, which is convenient for field work; through the RS232 interface connected with the computer, data acquisition, analysis and processing can be carried out.

[0026] In addition, the non-contact full-field strain measurement system adopts PMLAB DIC-3D non-contact three-dimensional strain optical measurement system, Digital Image Correlation digital image correlation technology is an algorithm for comparing related points through images, and the surface displacement and strain distribution of the object can be calculated through this method; during the whole measurement process, only one or two image collectors are needed to shoot the images of the measured object before and after deformation, and the 3D full-field strain data distribution can be obtained after operation; unlike strain gauge 7, which needs to spend a lot of time to polish and paste the surface, and can only measure the strain data of a point in a certain direction. Unlike the strict environmental requirements of the stripe interference method; the data obtained by DIC method is 3D data in the full-field range; PMLAB DIC-3D non-contact three-dimensional strain optical measurement system is mainly used for non-contact full-field measurement of three-dimensional coordinates, displacement and strain of objects; based on the principle of binocular stereo vision, the system collects the surface images of the object through double cameras, reconstructs the three-dimensional morphology by using digital image correlation algorithm, analyzes the deformation field, can detect the displacement distribution, principal strain direction and other parameters of the material under static and dynamic loading state, supports data interaction with LabView, ANSYS and other engineering software, and is suitable for mechanical property testing scenes of metals, composite materials and the like.

[0027] A test method for testing the rigidity coordination of a test structure of a gravel reinforcing structure with active unloading, comprising the following steps: S1, according to the length of gabion 9, placing two supports 1 on the experimental platform, placing gabion 9 on the two supports 1, and installing a plurality of tension link assemblies 10 on gabion 9 between the two supports 1, so that the plurality of tension link assemblies 10 are sequentially spaced along the length direction of gabion 9 and penetrate through gabion 9, and then sequentially applying a tightening force, i.e. a prestress, to each tension link assembly 10 according to the test specification; S2, before the tension link assembly 10 is fixed on the gabion 9, the strain gauge 7 is pasted on the tension link 4 in advance, and the strain gauge 7 is connected to the static strain meter after the tension link assembly 10 is fixed on the gabion 9; S3, the non-contact full-field strain measurement system is placed on the experimental platform, and the non-contact full-field strain measurement system is adjusted according to the position of the lower edge of the gabion 9, so that the non-contact full-field strain measurement system corresponds to the position of the lower edge of the gabion 9, and the displacement calibration of the position of the lower edge of the gabion 9 is performed; S4, then the two I-beams 6 are placed on the upper surface of the gabion 9, and the two I-beams 6 are symmetrically arranged with the length division line of the gabion 9 as the center line, and then the counterforce frame is placed on the experimental platform, and the two jacks 8 are correspondingly placed between the counterforce frame and the two I-beams 6; S5, when the counterforce frame, the two jacks 8 and the two I-beams 6 jointly apply load to the gabion 9, the static strain meter and the non-contact full-field strain measurement system synchronously collect the axial force of the tension link under the action of the load and the displacement data of the lower edge of the gabion 9; then the load applied to the gabion 9 is increased, and the deflection of the gabion 9 is measured, and then the tension link assembly 10 is adjusted to reduce the fastening force, i.e. the prestress, of the tension link assembly 10 on the gabion 9, at this time, the overall stiffness of the gabion 9 is reduced, the deflection is increased, and the relationship between the fastening force and the overall stiffness of the gabion 9 is analyzed, in addition, the relationship between the structural stiffness and the prestress and the load action can also be analyzed by reducing the load; S6, when the displacement data of the lower edge of the gabion 9 and the axial force of the tension link 4 under the action of the load are obtained, the displacement of the lower edge of the gabion 9 is: wherein P is the total load, the load applied by each of the two I-beams is P / 2, a is the distance from the support point to the adjacent loading point, L is the support span, E is the elastic modulus, I is the cross-sectional moment of inertia, and δ is the displacement of the lower edge, and the elastic modulus is: so as to calculate the overall stiffness of the gabion 9; the stiffness E is inversely calculated by using the simply supported beam theory, the relationship between the stiffness and the prestress is analyzed, the curve of the structural stiffness with the change of the reinforcement axial force, i.e. the prestress, and the external load is drawn, and the stiffness coordination law is analyzed, which provides a basis for the design of the active unloading structure in actual engineering.

[0028] The application can realize the change characteristics of the stiffness of the active unloading type rubble 3 reinforcing structure in the unloading process in the simulated tunnel, can simulate the working state of the active unloading type rubble 3 reinforcing structure in the tunnel, realizes the stress in the unloading process by using the loading experiment method, and then realizes the stiffness change law research, thereby improving the scientificity and reliability of the tunnel supporting structure design and optimization, can truly restore the stress and unloading mechanism of the active unloading type rubble 3 reinforcing structure in the tunnel under the indoor condition, can truly reflect the overall stiffness evolution characteristics of the active unloading type rubble 3 reinforcing structure, has the advantages of simple structure, convenient operation, intuitive parameter monitoring and the like, significantly improves the scientificity, authenticity and reliability of the test results, and thereby provides a scientific basis for the reasonable design and application of the structure in the tunnel engineering.

[0029] The above merely describes the preferred embodiments of the present application, and is not intended to limit the scope of the present application, and any equivalent changes made by using the content of the present application and the drawings are included in the scope of the present application.

Claims

1. A stiffness coordination test structure for an actively unloading crushed stone reinforcement structure, set on an experimental platform, characterized in that: The experiment consists of two identical supports placed parallel to each other on an experimental platform. A gabion cage is mounted on both supports. Several tie rod assemblies are installed on the gabion cage between the two supports, extending vertically through the cage and spaced apart along its length. At least one strain gauge is installed on each tie rod assembly inside the gabion cage, and a static strain gauge is connected to the strain gauge. Two I-beams are symmetrically arranged on the upper surface of the gabion cage, with the length dividing line of the gabion cage as the centerline. A reaction frame is positioned directly above the two I-beams on the experimental platform. Jacks are installed on the upper surface of the two I-beams, positioned between the reaction frame and the I-beams. A non-contact full-field strain measurement system for measuring the displacement data of the lower edge of the gabion cage is also installed on the experimental platform.

2. The stiffness coordination test structure for the actively unloading crushed stone reinforcement structure according to claim 1, characterized in that: The length of the gabion is greater than the distance between the two supports, and both ends of the gabion extend beyond the supports.

3. The stiffness coordination test structure for the actively unloading crushed stone reinforcement structure according to claim 1, characterized in that: Gabion cages consist of a metal mesh cage that is hollow inside and filled with crushed stone.

4. The stiffness coordination test structure for the actively unloading crushed stone reinforcement structure according to claim 3, characterized in that: The crushed stone is stacked in layers along the height direction inside the metal wire mesh cage.

5. The stiffness coordination test structure for the actively unloading crushed stone reinforcement structure according to claim 1, characterized in that: The tie rod assembly includes a tie rod that runs vertically through the gabion cage. Both ends of the tie rod extend outward from the gabion cage. Both ends of the tie rod are threaded with fastening nuts, which work together to fix the tie rod to the gabion cage.

6. The stiffness coordination test structure for the actively unloading crushed stone reinforcement structure according to claim 5, characterized in that: Two strain gauges are installed on the outer surface of each tie rod. The two strain gauges are spaced apart along the length of the tie rod. Both strain gauges are located inside the gabion cage and are connected to a static strain gauge.

7. The stiffness coordination test structure for the actively unloading crushed stone reinforcement structure according to claim 1, characterized in that: When the gabion is subjected to a load applied by two jacks, the overall stiffness of the gabion is obtained by simultaneously acquiring the displacement data of the gabion through a non-contact full-field strain measurement system and the axial force of the tie rod measured by a static strain gauge, and by combining the deflection calculation formula of a simply supported beam.

8. The stiffness coordination test structure for the actively unloading crushed stone reinforcement structure according to claim 1, characterized in that: When a gabion is subjected to a load applied by two jacks, the overall stiffness of the gabion changes with the change in the fastening force applied to the gabion by the tie rod assembly.

9. The stiffness coordination test structure for the actively unloading crushed stone reinforcement structure according to claim 1, characterized in that: The overall stiffness of the gabion and the fastening force exerted on the gabion by the tie rod assembly vary with the load on the gabion.

10. A test method for the stiffness compatibility test structure of an actively unloading crushed stone reinforcement structure according to any one of claims 1-9, characterized in that: Includes the following steps: S1. Place two supports on the experimental platform according to the length of the gabion cage, place the gabion cage on the two supports, and install several tie rod assemblies on the gabion cage between the two supports, so that the tie rod assemblies are spaced apart and pass through the gabion cage along the length of the gabion cage. Then, apply a fastening force to each tie rod assembly in sequence according to the test specifications. S2. Before fixing the tie rod assembly on the gabion cage, strain gauges are attached to the tie rods. After the tie rod assembly is fixed on the gabion cage, the strain gauges are connected to the static strain gauge. S3. Place the non-contact full-field strain measurement system on the experimental platform and adjust the non-contact full-field strain measurement system according to the position of the lower edge of the gabion cage so that the position of the non-contact full-field strain measurement system corresponds to the position of the lower edge of the gabion cage. S4. Then place two I-beams on the upper surface of the gabion cage, with the two I-beams symmetrically arranged with the length dividing line of the gabion cage as the center line. Then place the reaction frame on the experimental platform and place two jacks between the reaction frame and the two I-beams. S5. When the reaction frame, two jacks and two I-beams work together to apply load to the gabion, the static strain gauge and the non-contact full-field strain measurement system simultaneously collect the axial force of the tie rod under the load and the displacement data of the lower edge of the gabion. S6. When the displacement data of the lower edge of the gabion cage and the axial force of the tie rod under load are obtained, the displacement of the lower edge of the gabion cage is: Where P is the total applied load, a is the distance from the support point to the adjacent loading point, L is the support span, E is the elastic modulus, I is the moment of inertia of the section, and δ is the displacement of the lower edge. Therefore, the elastic modulus is: Thus, the overall stiffness of the gabion is calculated.

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