Construction method of steel-plastic grating rib band elastic tensile model and determination method of optimal reinforcement ratio

Abstract

The invention relates to the technical field of method construction, in particular to a construction method of a steel-plastic grating rib belt elastic tensile model and a determination method of the optimal reinforcement ratio. Comprising the following steps: (1) carrying out a tensile test on the steel-plastic grating rib belt and steel wires and polyethylene rib belts in the steel-plastic grating rib belt to obtain a stress-strain and tension curve and an elastic modulus distribution curve; (2) establishing an ideal constitutive model of the steel-plastic grating rib belt, and obtaining an ideal model expression equation # imgabs0 #; (3) correcting the ideal constitutive model; and obtaining a constitutive model expression equation # imgabs1 # conforming to the tensile property of the steel-plastic grating rib belt. The tensile mechanical properties of the three materials are analyzed and researched on the basis of tensile tests of the steel wire, the polyethylene rib belt and the steel-plastic grating rib belt. A steel-plastic grating rib belt composite rib belt elasticity modulus constitutive relation model is established, and the tensile mechanical properties of the steel-plastic grating rib belt at different reinforcement ratios are accurately and effectively reflected.

Description

Technical Field

[0001] The present invention relates to the technical field of method construction, and in particular to a method for constructing an elastic tensile model of a steel-plastic grid reinforcement strip and a method for determining an optimal reinforcement ratio. Background Art

[0002] At present, geocomposite materials have been widely used in various engineering fields. Composite materials have become an important direction for the development of new materials and new technologies due to their performance advantages. As a typical representative of geocomposite materials, steel-plastic grid reinforcement belts have become an irreplaceable part of geotechnical engineering reinforcement fields such as anchor support, soft soil foundation reinforcement, retaining wall and road crack resistance due to their excellent mechanical properties and corrosion resistance. Steel-plastic grid is a planar mesh structure formed by longitude and latitude welding of steel-plastic grid reinforcement belts. In the engineering application of steel-plastic grid, steel-plastic grid reinforcement belts are used as basic force-bearing units. The tensile mechanical properties of steel-plastic grid reinforcement belts themselves fundamentally determine the effectiveness and safety of steel-plastic grid engineering reinforcement. However, steel-plastic grid reinforcement belts are made of a composite of steel wire and polyethylene materials. The mechanical properties they exhibit are not the mechanical properties of a single material, which results in the complexity of the tensile mechanical characteristics of the grid reinforcement belts.

[0003] In the tensile test of composite materials, many existing technologies have publicly analyzed the tensile failure types of various composite materials, summarized the influence of different factors on the tensile properties of composite materials, and studied and compared the tensile mechanical properties of different composite materials. In the tensile mechanism of composite materials, the existing technologies have established constitutive models for failure prediction, damage, stress and strain of different composite materials based on the tensile mechanical properties of various composite materials. However, there are few studies on the tensile properties of new geocomposite materials such as steel-plastic grid reinforcement belts, and a complete theoretical calculation system has not yet been formed. Summary of the invention

[0004] In view of the problem that there is no elastic tensile model for composite materials such as steel-plastic grid reinforcement belts in the prior art, the present invention provides a method for constructing an elastic tensile model for steel-plastic grid reinforcement belts and a method for determining the optimal reinforcement ratio to solve the above problems. The present invention applies fiber composite theory to establish a constitutive relationship model of the elastic modulus of steel-plastic grid reinforcement belts. The constitutive model is modified from the two aspects of material damage and steel wire incompatibility, and the applicability and accuracy of the constitutive model are verified by fitting with experimental data. Finally, based on the established constitutive model, the optimal reinforcement ratio of the steel-plastic grid reinforcement belt is derived. The present invention has important practical significance for the mechanical calculation and engineering application of steel-plastic geogrid composite materials.

[0005] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a method for constructing an elastic tensile model of a steel-plastic grid rib, comprising the following steps: (1) Conduct tensile tests on the steel-plastic grating reinforcement belt and the steel wire and polyethylene reinforcement belt in the steel-plastic grating reinforcement belt to obtain stress-strain and tensile force curves and elastic modulus distribution curves; (2) Establish the ideal constitutive model of steel-plastic grid reinforcement strip and obtain the ideal model expression equation (1): Formula (1); In the formula, E c is the ideal elastic modulus of the tendon; E s is the elastic modulus of the steel wire; E m is the elastic modulus of polyethylene; λ s is the reinforcement ratio; (3) Modification of the ideal constitutive model; obtaining the constitutive model expression equation (3) that conforms to the tensile properties of the steel-plastic grid reinforcement: Formula (3); In the formula, is the elastic modulus of the reinforcement test; ξ is the damage residual coefficient; E c is the ideal elastic modulus of the tendon; the correction is the material damage correction.

[0006] Furthermore, the damage residual coefficient equation is as follows (2): Formula (2); Where: is the damage residual coefficient; is the reinforcement ratio; is the mathematical expectation value of the reinforcement ratio; A is an unknown constant obtained through experimental fitting; S is the standard deviation of the reinforcement ratio.

[0007] Furthermore, it also includes a secondary correction of the ideal constitutive model, wherein the secondary correction is a correction for the incompatibility of the steel wire; after the secondary correction, the constitutive model expression equation (5) after the secondary correction that meets the tensile properties of the steel-plastic grid reinforcement strip is obtained: Formula (5); In the formula, E f is the elastic modulus of the reinforcement strip test after secondary correction; ξ is the damage residual coefficient; η is the coordination coefficient; E c is the ideal elastic modulus of the tendon.

[0008] Furthermore, the steel wire incompatibility correction equation is as follows (4): Formula (4); Where: η is the coordination coefficient; λ s is the reinforcement ratio; m, n, k are unknown constants obtained through experimental fitting.

[0009] Furthermore, the tensile test method of step (1) is as follows: (1) The specimen is placed in an environment with a temperature of 23±5℃ for at least 24h and a tensile test is carried out in this environment; (2) Pre-tensioning is performed before the tensile test, and the pre-tensioning force is 1% of the maximum load; (3) After pre-tensioning, install the extensometers at the middle of the steel wire, polyethylene reinforcement strip, and steel-plastic grid reinforcement strip, and after the extensometer readings are reset to zero, conduct a formal tensile test; (4) For the tensile test, set the original gauge length to 20-25 cm and the loading rate to 10 mm / min; (5) Tensile tests are all performed using displacement increment loading until complete breaking occurs, and the stress and strain of the tensile material are recorded throughout the process.

[0010] Furthermore, the tensile test uses a microcomputer-controlled electro-hydraulic servo universal testing machine; the extensometer model is YYU-5 / 50.

[0011] In a second aspect, the present invention provides a method for determining the optimal reinforcement ratio of an elastic tensile model of a steel-plastic grid reinforcement strip, comprising: determining the optimal reinforcement ratio according to the model constructed as above.

[0012] The beneficial effects of the present invention are: The present invention is based on the tensile tests of steel wire, polyethylene reinforcement, and steel-plastic grille reinforcement, and analyzes and studies the tensile mechanical properties of the three materials. A constitutive relationship model of the elastic modulus of the composite reinforcement of steel-plastic grille reinforcement is established, which accurately and effectively reflects the tensile mechanical properties of the steel-plastic grille reinforcement at different reinforcement ratios. According to the results of the tensile test and based on the fiber composite theory, an ideal model of the tensile elastic modulus of the steel-plastic grille reinforcement is established, and the model is modified by considering the material damage and the incoordination of the steel wire, and finally the constitutive model of the elastic modulus of the composite reinforcement of steel-plastic grille reinforcement is established. It has been verified that the determination coefficient R of the modified constitutive model 2 The fitting value and fitting trend are both highly consistent with the experimental value. At the same time, the present invention also analyzes the optimal reinforcement ratio of the steel-plastic grid reinforcement belt according to the elastic modulus constitutive model of the composite reinforcement belt of the steel-plastic grid reinforcement belt. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0014] Figure 1 1 is a tensile strain curve diagram of steel wires of different diameters in Example 1, in which A is the dividing point between the elastic stage and the strengthening stage of the steel wire; and B is the extreme point of the strengthening stage of the steel wire.

[0015] Figure 2 1 is a stress-strain curve diagram of the elastic stage of steel wires with different diameters in Example 1.

[0016] Figure 3 1 is a stress-strain and tension curve of the polyethylene tendon in Example 1.

[0017] Figure 4 This is a distribution diagram of the elastic modulus values ​​of the polyethylene tendons in Example 1.

[0018] Figure 5 It is the stress-strain curve diagram of the SR-1~SR-3 steel-plastic grid reinforcement strips in Example 1.

[0019] Figure 6 It is the stress-strain curve diagram of the SR-4~SR-6 steel-plastic grid reinforcement belt in Example 1.

[0020] Figure 7 It is the stress-strain curve diagram of the SR-7~SR-9 steel-plastic grid reinforcement belt in Example 1.

[0021] Figure 8 It is the stress-strain curve diagram of the SR-10~SR-13 steel-plastic grid reinforcement belt in Example 1.

[0022] Fig. 9 It is a schematic diagram of the steel-plastic grid rib model under the ideal constitutive model in Example 2.

[0023] Fig.10 This is a schematic diagram of the non-cooperative deformation of the steel wire in Example 2.

[0024] Fig.11 It is a schematic diagram of the steel-plastic grid rib model under the secondary modified constitutive model in Example 2.

[0025] Fig.12 It is a comparison chart of the tensile test value of the steel-plastic grid reinforcement strip in Example 1 and the three fitting curves in Example 2. DETAILED DESCRIPTION

[0026] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0027] Example 1 Tensile test of steel wire, polyethylene reinforcement and steel-plastic grid reinforcement The steel-plastic grille reinforcement belt used in the test is made of steel wire as the skeleton and polyethylene material as the base coating. The steel wire used in the test is cold-drawn non-alloy steel wire for springs. The polyethylene reinforcement belt used in the test is made of pure polyethylene. All three materials are produced by Tai'an Runde Composite Materials Co., Ltd., and the material parameters of the steel wire and polyethylene reinforcement belt used in the test are exactly the same as those used in the production of steel-plastic grille reinforcement belts.

[0028] 1. Test equipment: The tensile test instruments for steel wire, polyethylene reinforcement and steel-plastic grille reinforcement are all microcomputer-controlled electro-hydraulic servo universal testing machines, and the stress-strain test devices are all YYU-5 / 50 extensometers produced by the Central Iron and Steel Research Institute.

[0029] 2. Experimental group design As the steel wire of the steel-plastic grille reinforcement belt skeleton, three types of cold-drawn carbon steel wires with diameters of 0.5 mm, 0.6 mm and 0.7 mm were selected. Six repeated tests were conducted on different experimental groups of steel wire, polyethylene reinforcement belt and steel-plastic grille reinforcement belt. The detailed experimental group design is shown in Table 1.

[0030] Table 1 - Experimental group design table

[0031] 3. Test methods: The tensile test method is as follows: (1) The specimen is placed in an environment with a temperature of (23±5)℃ for at least 24h and the tensile test is carried out in this environment.

[0032] (2) Pre-tensioning is required before the tensile test, and the pre-tensioning force is 1% of the maximum load.

[0033] (3) After pre-tensioning, the extensometers are installed at the middle of the steel wire, polyethylene reinforcement strip, and steel-plastic grating reinforcement strip, and the extensometer readings are reset to zero before the formal tensile test is carried out.

[0034] (4) For the tensile test, set the original gauge length to 20-25 cm and the loading rate to 10 mm / min.

[0035] (5) Tensile tests are all performed using displacement increment loading until complete breaking occurs, and the stress and strain of the tensile material are recorded throughout the process.

[0036] 4. Test results and analysis (1) Analysis of tensile test results of single steel wire and polyethylene reinforcement The results of the single steel wire tensile test are as follows: Figure 1 and Figure 2 As shown. Figure 1From the tensile strain results of steel wires with different diameters, we can see that the maximum strain of steel wires with different diameters is between 1.4% and 1.5%. The maximum tensile force of 0.5mm steel wire reaches 428N, the maximum tensile force of 0.6mm steel wire reaches 693N, and the maximum tensile force of 0.7mm steel wire reaches 978N. In the steel wire tensile test, the deformation of the steel wire can be divided into the elastic stage and the strengthening stage. In the elastic stage, the stress-strain curve of the steel wire changes linearly, which conforms to Hooke's law. Therefore, this stage is the main basis for the elastic modulus of the steel wire. Figure 2 It can be seen that the stress-strain curves of steel wires of different diameters in the elastic stage are roughly consistent. After fitting and calculating the results of multiple sets of steel wire tensile tests, the final elastic modulus value of the steel wire is 210 GPa.

[0037] The tensile test results of a single polyethylene tendon are as follows: Figure 3 and Figure 4 As shown. Figure 3 It can be seen that the maximum strain of the polyethylene tendon reaches 10.82%, the maximum stress reaches 25MPa, and the maximum tensile force reaches 326N. In the tensile test of the polyethylene tendon, the deformation of the polyethylene tendon can be divided into a strengthening stage and a local deformation stage. The strain in the strengthening stage is generally 0~8.47%, and the strain in the local deformation stage is generally 8.47%~10.82%. The tensile elastic modulus of the polyethylene tendon can be determined by the chord modulus. The determination method is: determine the upper and lower force points on the stress-strain curve, draw a chord between the two points, and the slope is the chord modulus. Figure 4 As shown, by conducting tension tests on multiple groups of polyethylene tendons, the elastic modulus value of the polyethylene tendons was finally obtained to be 0.75 GPa through fitting calculation.

[0038] (2) Analysis of tensile test results of steel-plastic grid reinforcement The tensile test results of steel-plastic grid reinforcement are as follows Figure 5~Figure 8 As shown. Figure 5~Figure 8 It can be seen that before the steel-plastic grille reinforcement belt reaches the maximum stress, the stress-strain curve shows a fluctuating but stable upward trend. This is due to the large number of steel wires in the composite reinforcement belt and the coordinated force between the steel wires. When the composite reinforcement belt reaches the maximum tension, the stress-strain curve shows an irregular zigzag downward trend. This is because the internal steel wires of the composite reinforcement belt begin to break gradually at this stage, and they are not broken all at once, but progressively broken. When the internal steel wires of the composite reinforcement belt are completely broken, the stress-strain curve of the composite reinforcement belt presents a relatively smooth straight line. At this time, the tensile effect of the composite reinforcement belt is only provided by the polyethylene material. The first breaking strain of the steel wire in the steel-plastic grille reinforcement belt generally occurs between 1.1% and 1.5% (60% of the breaking events are concentrated at a strain of 1.4% to 1.5%), and the final breaking strain generally occurs between 1.5% and 2.5% (70% of the breaking events are concentrated at a strain of 1.5% to 1.8%).

[0039] Taking into account the tensile deformation characteristics of the steel wire itself and the coordinated force between the steel wires in the reinforcement belt when subjected to tension, the present invention selects the middle and relatively smooth position of the stress-strain curve before the steel-plastic grating reinforcement belt reaches the maximum stress as the basis for selecting the elastic modulus of the steel-plastic grating reinforcement belt.

[0040] The six repeated tests of different test groups of steel-plastic grid reinforcement belts were calculated separately, and the least square method was used for regression fitting, and finally the tensile elastic modulus of the steel-plastic grid reinforcement belt with different reinforcement ratios was obtained. The detailed calculation results of the elastic modulus are shown in Table 2.

[0041] Table 2- Calculation table of elastic modulus of steel-plastic grating reinforcement

[0042] Example 2 Establishment of elastic modulus constitutive model of steel-plastic grid ribs 1. Establishment of ideal constitutive model The steel-plastic grille reinforcement belt is a rectangular strip-shaped reinforcement belt formed by polyethylene coated steel wire. For the steel-plastic grille reinforcement belt, polyethylene is the matrix and steel wire is the reinforcement. Polyethylene mainly plays the role of bonding reinforcement, and steel wire mainly plays the role of reinforcement. The two together constitute the steel-plastic grille reinforcement belt.

[0043] Compared with fibers, steel-plastic grille reinforcement belts are macro-composite materials, and the composite of polyethylene and steel wire is a one-dimensional linear combination. Therefore, the reinforcement ratio of steel wire in steel-plastic grille reinforcement belts is an important indicator in mechanical research. When tension is applied to both ends of the steel-plastic grille reinforcement belt, the tension will be transmitted longitudinally along the polyethylene matrix and the steel wire reinforcement, and will be borne by polyethylene and steel wire. According to the mechanical constitutive relationship analysis, the two materials are in a parallel relationship. At the same time, both steel wire and polyethylene matrix are elastic materials, and their mechanical properties conform to Hooke's law. Therefore, a constitutive model of a composite reinforcement belt composed of a steel wire group and a polyethylene matrix can be established, such as Fig. 9 As shown. Then the ideal model expression equation of the elastic modulus of the steel-plastic grid rib is as follows (1): Formula (1); In the formula, E c is the ideal elastic modulus of the tendon; E s is the elastic modulus of the steel wire, which can be obtained experimentally; E m is the elastic modulus of polyethylene, which can be obtained experimentally; λ s It is the reinforcement ratio.

[0044] 2. Modification of the ideal constitutive model (1) Effect of material damage on the constitutive model The classical elastic modulus composite mechanism is a mathematical derivation based on an ideal model, and its accuracy often needs to be corrected in practice to meet the accuracy of the constitutive model. The ideal model of the elastic modulus of the steel-plastic grille reinforcement also needs to be corrected. According to the tensile test of the steel-plastic grille reinforcement and the structure of the steel-plastic grille reinforcement, the reinforcement first undergoes uncoordinated stretching of the steel wire, and then the steel wire breaks. The breakage damage of a single steel wire or polyethylene material is one of the important factors affecting the performance of the reinforcement. The coefficient of influence of the steel wire or polyethylene belt on the reinforcement constitutive model after damage is called the damage residual coefficient, which is expressed as The damage variable is expressed by the reinforcement ratio. Since the damage residual coefficient also conforms to the normal distribution law, it is assumed that the damage residual coefficient equation for the reinforcement ratio is as follows (2): Formula (2); Where: is the damage residual coefficient; is the reinforcement ratio; is the mathematical expectation of the reinforcement ratio; A is an undetermined constant, which can be obtained through experimental fitting; S is the standard deviation of reinforcement ratio.

[0045] Then the elastic modulus evolution equation of the reinforcement strip with respect to the material damage residual coefficient can be modified to the following equation (3): Formula (3); Where: E ξ is the elastic modulus corrected by the residual coefficient of tendon damage; ξ is the damage residual coefficient; E c is the ideal elastic modulus of the tendon.

[0046] (2) Influence of steel wire incompatibility on constitutive model From the stress-strain curve of the steel-plastic grating reinforcement belt, it can be seen that the steel wire breaks progressively in the breaking stage. After each break, a certain amount of strain energy is accumulated before breaking again. The main reason is that due to the production process, all steel wires are not completely straight, and the steel wires will bend to varying degrees, such as Fig.10 As shown in the figure. This leads to uncoordinated deformation between the steel wires, with some of the steel wires being stressed first and the other parts being stressed later, resulting in progressive breaking of the steel wires. Moreover, the strain increments of progressive breaking of the steel wires are not the same, which depends on the degree of bending of the steel wires. Therefore, the influence of the incoordination of the steel wires on the constitutive model is direct and must be considered.

[0047] In order to quantitatively describe the influence of steel wire compatibility on the constitutive model, the compatibility coefficient is defined , the coordination coefficient is directly related to the reinforcement ratio. In order to keep the same variable as the damage residual coefficient, the reinforcement ratio is used as one of the quantitative parameters of the coordination coefficient. Assuming that the coordination coefficient is also a logarithmic function of the reinforcement ratio, the coordination coefficient formula can be expressed as the following formula (4): Formula (4); Where: η is the coordination coefficient; λ s is the reinforcement ratio; m, n, and k are unknown constants that can be obtained through experimental fitting.

[0048] 3. Establishment and verification of elastic modulus constitutive model of steel-plastic grid reinforcement The main factor affecting the tensile properties of the steel strip is the coordination relationship between the single steel wire and the steel wire. The ideal constitutive model is modified by introducing the damage residual module and the incoordination module, so as to establish the modified constitutive model of the steel-plastic grid steel strip. Fig.11 As shown. By introducing the damage residual coefficient for a first correction and then introducing the coordination coefficient for a second correction, the rational model expression (2) is corrected to the constitutive model expression equation (5) that conforms to the tensile properties of the steel-plastic grid reinforcement: Formula (5); Where: E f is the elastic modulus of the reinforcement strip test after secondary correction; ξ is the damage residual coefficient; η is the coordination coefficient; E c is the ideal elastic modulus of the tendon.

[0049] The test results obtained in the tensile test (elastic modulus of steel wire 210 GPa, elastic modulus of polyethylene reinforcement 0.75 GPa and elastic modulus of steel-plastic grating reinforcement shown in Table 2) were fitted with the equation of the present invention, and the values ​​of the unknown constants A, m, n, and k of the damage residual coefficient ξ and the coordination coefficient η were determined by the least squares method, as shown in Table 3.

[0050] Table 3 - Table of values ​​of constants to be determined in the present invention

[0051] In order to verify the accuracy of the constitutive model, the tensile test value of the steel-plastic grid reinforcement, the ideal model elastic modulus equation (1), the damage residual coefficient corrected elastic modulus equation (3) and the final corrected constitutive model equation (5) are plotted as shown in the figure. Fig.12 shown.

[0052] Depend on Fig.12 It can be seen that the elastic modulus formula (1) of the ideal model is significantly different from the experimental value and has no fitting value. After one correction, the constitutive equation (3) fits the experimental value better, and the determination coefficient R 2 It reaches 0.9716, but with the increase of reinforcement ratio, the elastic modulus of the corresponding fitting curve is significantly higher than the experimental value, and the difference in the increasing trend is getting larger and larger. Therefore, although the fitting results of formula (1) and formula (3) are good, they are still far from satisfactory in terms of relative trend. The constitutive model equation (5) corrected by the double coefficients of damage residual coefficient ξ and coordination coefficient η has the highest accuracy, and the determination coefficient R 2 When the fitting value and fitting trend are both highly consistent with the experimental value, the fitting effect is the best.

[0053] 4. Optimal reinforcement ratio analysis based on the constitutive model of steel-plastic grid reinforcement strip By fitting the constitutive model equation, it can be seen that the constitutive equation (5) of the steel-plastic grid reinforcement has a good fitting accuracy with the experimental value, and the value of the unknown constant is obtained through the experiment. The unknown constant is substituted into the ideal model expression equation (1) of the reinforcement elastic modulus and the damage residual coefficient Equation (2), coordination coefficient In equation (4), we can get equations (6) to (9): Formula (6); Formula (7); Formula (8); Formula (9).

[0054] Therefore, the reinforcement strip constitutive model equation (5) can be further derived into an equation about the reinforcement ratio, as shown in equation (10): Formula (10).

[0055] Since formula (10) is a fitting equation based on the reinforcement ratio between 4.58% and 22.07%, it is credible to study the variation law of its elastic modulus in this range. By taking the derivative of formula (10), it can be seen that when the reinforcement ratio is 12.3%, the constitutive equation reaches a maximum value. Although its elastic modulus exceeds the maximum value when the reinforcement ratio exceeds 16.8%, it will increase the amount of steel wire by about 36.6%. Therefore, in the absence of special requirements, the most economical and efficient reinforcement ratio is 12.3%.

[0056] Although the present invention has been described in detail with reference to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person of ordinary skill in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Any person of ordinary skill in the art may easily think of changes or substitutions within the technical scope disclosed by the present invention, and these shall be within the scope of protection of the present invention.

Claims

1. A method for constructing an elastic tensile model of a steel-plastic grid rib, characterized in that: The following steps are involved: (1) Tensile tests were conducted on steel-plastic grating reinforcement strips, steel wires and polyethylene reinforcement strips to obtain the following data: elastic modulus of steel wire, modulus of polyethylene reinforcement strips and modulus of steel-plastic grating reinforcement strips at different reinforcement ratios; (2) Establish the ideal constitutive model of steel-plastic grid reinforcement strip and obtain the ideal model expression equation (1): Formula (1); In the formula, E c is the ideal elastic modulus of the tendon; E s is the elastic modulus of the steel wire; E m is the elastic modulus of polyethylene; λ s is the reinforcement ratio; (3) Modification of the ideal constitutive model; obtaining the constitutive model expression equation (3) that conforms to the tensile properties of the steel-plastic grid reinforcement: Formula (3); In the formula, is the elastic modulus of the reinforcement band test; ξ is the damage residual coefficient; E c is the ideal elastic modulus of the tendon; the correction is the material damage correction.

2. The method for constructing the elastic tensile model of the steel-plastic grid rib strip according to claim 1, characterized in that: The damage residual coefficient equation is as follows (2): Formula (2); Where: is the damage residual coefficient; is the reinforcement ratio; is the mathematical expectation value of the reinforcement ratio; A is an unknown constant, which is obtained by substituting the data obtained in step (1) into the fitting; S is the standard deviation of the reinforcement ratio.

3. The method for constructing the elastic tensile model of the steel-plastic grid rib strip according to claim 1, characterized in that: The method for obtaining the elastic modulus of steel wire, the modulus of polyethylene reinforcement strip and the modulus of steel-plastic grid reinforcement strip under different reinforcement ratios is as follows: a. The tensile strain data and stress strain data of steel wires with different diameters are obtained through multiple sets of experiments, and the elastic modulus value of the steel wire is obtained through fitting calculation; b. Obtain the stress-strain curve of the polyethylene tendon through multiple sets of experiments, then determine the upper and lower force value points on the stress-strain curve, draw a chord between the two points, and its slope is the chord modulus; finally obtain the elastic modulus value of the polyethylene tendon through fitting calculation; c. Obtain stress-strain curves through multiple sets of repeated tests; take the middle and smooth part of the stress-strain curve before the steel-plastic grid reinforcement reaches the maximum stress as the basis for selecting the elastic modulus of the steel-plastic grid reinforcement; then calculate multiple sets of data separately, and use the least squares method for regression fitting, and finally obtain the tensile elastic modulus values ​​of the steel-plastic grid reinforcement at different reinforcement ratios.

4. The method for constructing the elastic tensile model of the steel-plastic grid rib strip according to claim 1, characterized in that: It also includes a secondary correction of the ideal constitutive model, wherein the secondary correction is a correction for the incompatibility of the steel wire; after the secondary correction, the constitutive model expression equation (5) after the secondary correction that meets the tensile properties of the steel-plastic grid reinforcement strip is obtained: Formula (5); In the formula, E f is the elastic modulus of the reinforcement strip test after secondary correction; ξ is the damage residual coefficient; η is the coordination coefficient; E c is the ideal elastic modulus of the tendon.

5. The method for constructing the elastic tensile model of the steel-plastic grid rib strip according to claim 4, characterized in that: The coordination coefficient equation is as follows (4): Formula (4); Where: η is the coordination coefficient; λ s is the reinforcement ratio; m, n, k are unknown constants, which are obtained by substituting the data obtained from the experiment in step (1) into the fitting.

6. The method for constructing the elastic tensile model of the steel-plastic grid rib strip according to claim 1, characterized in that: The tensile test method of step (1) is as follows: (1) The specimen is placed in an environment with a temperature of 23±5℃ for at least 24h and a tensile test is carried out in this environment; (2) Pre-tensioning is performed before the tensile test, and the pre-tensioning force is 1% of the maximum load; (3) After pre-tensioning, install the extensometers at the middle of the steel wire, polyethylene reinforcement strip, and steel-plastic grid reinforcement strip, and after the extensometer readings are reset to zero, conduct a formal tensile test; (4) For the tensile test, set the original gauge length to 20-25 cm and the loading rate to 10 mm / min; (5) Tensile tests are all performed using displacement increment loading until complete breaking occurs, and the stress and strain of the tensile material are recorded throughout the process.

7. The method for constructing the elastic tensile model of the steel-plastic grid rib strip according to claim 6, characterized in that: The tensile test uses a microcomputer-controlled electro-hydraulic servo universal testing machine; the extensometer model is YYU-5 / 50.

8. A method for determining the optimal reinforcement ratio of a steel-plastic grid reinforcement strip elastic tensile model, characterized in that: According to the model constructed by the construction method as claimed in claim 1, the optimal reinforcement ratio is determined.

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