Rubber sand mixed soil compression deformation prediction method and system

Abstract

The invention discloses a rubber sand mixed soil compression deformation prediction method and system, and the method comprises the steps: obtaining vertical stress-vertical strain data of rubber sand mixed soil under different working conditions through a lateral confinement compression test of the rubber sand mixed soil; based on the vertical stress-vertical strain data, constructing a compressive deformation prediction model of the rubber sand mixed soil; and completing rubber sand mixed soil compression deformation prediction by using the compression deformation prediction model. The invention provides a rubber sand mixed soil compression deformation prediction model which is few in parameter, high in precision and convenient for engineering application. The method can be used for guiding design of rubber sand backfill compaction parameters, prediction of rubber sand backfill structure service period settlement and the like, and resource utilization of waste rubber particles in the fields of rock soil, roads, underground engineering and the like is promoted.

Description

Technical Field

[0001] The invention relates to the field of novel rock-soil composite materials, and in particular to a method and system for predicting compression deformation of rubber-sand mixed soil. Background Art

[0002] Insufficient recycling of waste tires has caused serious waste of resources and environmental pollution. Therefore, it is urgent to accelerate the green and resource-based large-scale utilization of waste tires in the field of civil engineering. Studies have shown that the rubber sand mixed soil formed by mixing the rubber particles formed by crushing waste tires with natural sand in a certain proportion has the characteristics of light density, low modulus, large damping, high shear strength and good permeability. It is a new type of green and low-cost geotechnical composite material that can be used as backfill material for roadbeds, underground structures, retaining walls and foundations to reduce the deadweight of backfill soil, reduce the settlement of soft roadbeds, reduce soil pressure, and play a role in vibration reduction and seismic isolation.

[0003] However, when rubber sand is backfilled into the structure, the high elasticity and low modulus rubber particles may produce excessive deformation, which may damage the service safety of the structure. Therefore, it is of great significance to reasonably estimate the compression deformation of rubber sand mixed soil for rubber sand parameter design, backfill quality control and structural settlement control. In the early days, some road subgrades often used large-sized pure rubber strips or coarse aggregates for local backfilling to reduce the load, and their compression deformation characteristics were studied more. However, large-scale backfilling of pure rubber strips or coarse aggregates can easily lead to excessive surface or structural settlement and cause fires. Therefore, the above problems can be effectively solved by mixing with natural soil in an appropriate proportion. At present, there are relatively few studies on the compression deformation of rubber sand mixed soil, and there is no report on the compression deformation prediction method considering the influence of rubber content and particle size, which is not conducive to its engineering application. Summary of the invention

[0004] In view of the technical problems in the above background, the purpose of the present invention is to propose a method for predicting the compression deformation of rubber-sand mixed soil, which can take into account the influence of three key factors: rubber particle size, rubber content and vertical pressure. This method has few unknown parameters and high accuracy, and is suitable for predicting the compression deformation of rubber-sand mixed soil commonly used in actual engineering.

[0005] To achieve the above object, the present invention provides a method for predicting compression deformation of rubber-sand mixed soil, the steps comprising:

[0006] Through the confined compression test of rubber-sand mixed soil, the vertical stress-vertical strain data of rubber-sand mixed soil under different working conditions are obtained;

[0007] Based on the vertical stress-vertical strain data, a compression deformation prediction model of rubber-sand mixed soil is constructed;

[0008] The compression deformation prediction model is used to complete the compression deformation prediction of rubber-sand mixed soil.

[0009] Preferably, when conducting the lateral confined compression test, experimental materials with the same non-uniformity coefficient are selected, including sand materials and rubber particle materials; for rubber particles with different median particle sizes, rubber-sand mixed soils with different mortar-sand particle size ratios and rubber contents are prepared according to the rubber mass ratio; lateral confined compression tests are carried out under different vertical stress conditions to obtain the vertical stress-vertical strain data of the rubber-sand mixed soil under different working conditions.

[0010] Preferably, based on the basic principles of soil mechanics and in combination with the acquired vertical stress-vertical strain data, the porosity of the rubber-sand mixture under different vertical stresses is derived, and the initial model is determined based on the individual and coupled effects of the mortar-sand particle size ratio, rubber content, and vertical stress; based on the test data, data normalization, logarithmic transformation, and least squares method are used to determine the optimal values ​​of the unknown parameters in the initial model, thereby constructing a compression deformation prediction model for the rubber-sand mixture.

[0011] Preferably, the compression deformation prediction model constructed includes:

[0012]

[0013] Where, ε represents the vertical strain; e 12.5 represents the void ratio of the mixed soil under 12.5 kPa vertical stress; SR represents the mortar-sand particle size ratio; RC represents the rubber content; σ v represents vertical stress; σ r represents the reference vertical stress.

[0014] The present invention also provides a system for predicting compression deformation of rubber-sand mixed soil, the system being used to implement the above method, comprising: a test module, a construction module and a prediction module;

[0015] The test module is used to obtain vertical stress-vertical strain data of the rubber-sand mixed soil under different working conditions through a confined compression test of the rubber-sand mixed soil;

[0016] The construction module is used to construct a compression deformation prediction model of rubber-sand mixed soil based on the vertical stress-vertical strain data;

[0017] The prediction module is used to complete the compression deformation prediction of rubber-sand mixed soil using the compression deformation prediction model.

[0018] Preferably, when conducting the lateral confined compression test, experimental materials with the same non-uniformity coefficient are selected, including sand materials and rubber particle materials; for rubber particles with different median particle sizes, rubber-sand mixed soils with different mortar-sand particle size ratios and rubber contents are prepared according to the rubber mass ratio; lateral confined compression tests are carried out under different vertical stress conditions to obtain the vertical stress-vertical strain data of the rubber-sand mixed soil under different working conditions.

[0019] Preferably, the workflow of the construction module includes: based on the basic principles of soil mechanics, combined with the acquired vertical stress-vertical strain data, deriving the porosity of the rubber-sand mixed soil under different vertical stresses, and determining the initial model based on the separate and coupled effects of the mortar-sand particle size ratio, rubber content, and vertical stress; based on the test data, using data normalization, logarithmic transformation and least squares method to determine the optimal values ​​of the unknown parameters in the initial model, thereby constructing a compression deformation prediction model for the rubber-sand mixed soil.

[0020] Preferably, the constructed compression deformation prediction model includes:

[0021]

[0022] Where, ε represents the vertical strain; e 12.5 represents the void ratio of the mixed soil under 12.5 kPa vertical stress; SR represents the mortar-sand particle size ratio; RC represents the rubber content; σ v represents vertical stress; σ r represents the reference vertical stress.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The method for predicting the compression deformation of rubber-sand mixed soil proposed in the present invention is based on the basic physical properties of rubber sand and confined compression test data, and the test scheme is reasonable, the test results are reliable, and the data processing method is rigorous. The present invention takes into account three main factors affecting the compression deformation of rubber-sand mixed soil, namely, the mortar particle size ratio, the rubber content, and the vertical stress, and can describe its compression deformation characteristics and change laws, with high prediction accuracy. The method has a solid theoretical basis, uses fewer parameters, has clear physical meanings, and can all be determined by experiments, which is convenient for direct application in actual engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0026] Figure 1 It is a schematic diagram of a flow chart of an embodiment of the present invention;

[0027] Figure 2 The different mortar particle size ratios SR of the embodiments of the present invention (e i / e 12.5 ) and lg(σ v / σ r ) of the linear fitting curve; wherein (a) represents the fitting curve under the condition of SR = 0.1; (b) represents the fitting curve under the condition of SR = 0.5; (c) represents the fitting curve under the condition of SR = 1.0; (d) represents the fitting curve under the condition of SR = 3.0;

[0028] Figure 3 1 is a curve showing the relationship between the parameters α and β and the rubber content RC of the embodiment of the present invention; wherein (a) shows the curve showing the relationship between α and RC; (b) shows the curve showing the relationship between β and RC;

[0029] Figure 4 1 is a curve showing the relationship between coefficients k1 and k2 and the mortar particle size ratio SR of an embodiment of the present invention; wherein (a) shows the curve showing the relationship between coefficient k1 and SR; (b) shows the curve showing the relationship between k2 and the mortar particle size ratio SR;

[0030] Figure 5 Comparison between the experimental value of the embodiment of the present invention and the predicted value of the method;

[0031] Figure 6 Comparison between the experimental values ​​of Zhang Yongfu et al. in the embodiment of the present invention and the predicted values ​​of this method;

[0032] Figure 7 1 is a comparison between the experimental values ​​of Won et al. in the embodiment of the present invention and the predicted values ​​of the present method; wherein (a) represents the comparison under the condition of SR=0.44; (b) represents the comparison under the condition of SR=1.27; (c) represents the comparison under the condition of SR=1.87; (d) represents the comparison under the condition of SR=4.0;

[0033] Figure 8 1 is a comparison between the test values ​​of Badarayani et al. in the embodiment of the present invention and the predicted values ​​of the present method; wherein (a) represents the comparison under the condition of e0=0.65; and (b) represents the comparison under the condition of e0=0.75. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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 are within the scope of protection of the present invention.

[0035] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] Embodiment 1

[0037] like Figure 1 FIG. 1 is a schematic diagram of the method flow of this embodiment, and the steps include:

[0038] S1. Through the lateral confined compression test of rubber sand mixed soil, the vertical stress-vertical strain data of rubber sand mixed soil under different working conditions are obtained.

[0039] In this embodiment, when conducting the confined compression test, Fujian standard sand and rubber particle materials with the same non-uniformity coefficient are selected, and rubber sand mixed soil with different rubber sand particle size ratios and rubber contents are prepared according to the rubber mass ratio for rubber particles with different median particle sizes. Confined compression tests are carried out under different vertical stress conditions to obtain vertical stress-vertical strain data of the rubber sand mixed soil under different working conditions.

[0040] The specific steps include:

[0041] Step 1.1: Selection of test equipment. The test data used in the compression deformation prediction method of rubber sand mixed soil constructed this time all come from the confined compression test of rubber sand mixed soil. The compression test uses a pneumatic double consolidation instrument, in which the sample box has a diameter of 100mm and a height of 50mm; the maximum vertical stress is 500kPa, and the displacement meter range is 25mm, which can realize automatic recording of test data.

[0042] Step 1.2: Preparation of rubber sand mixed soil samples and test plan. Fujian standard sand and rubber particles were used in this test. The mortar sand particle size ratios (SR) considered in the test were 0.1, 0.5, 1.0 and 3.0, and the rubber content (mass ratio, RC) were 0% (pure sand), 5%, 10%, 20%, 30% and 50%, respectively. According to the relevant geotechnical test procedures, the maximum and minimum dry densities of rubber sand mixed soil under different mortar sand particle size ratios and rubber content conditions were determined. According to the test conditions, the sand particles and rubber particles were fully mixed, vibrated and compacted to the predetermined height in three layers to prepare a medium-dense sample with a relative density of 70%.

[0043] Step 1.3: Apply a sequence of vertical loads. The load sequence applied in the lateral confinement compression test is 12.5, 25, 50, 100, 150, 200, 300, and 400 kPa. After the deformation of the rubber-sand mixed soil sample reaches a stable state under each level of load, start applying the next level of load, and apply the load step by step. After all loads are applied, stop loading, and check and process the test data. According to the test plan, samples are prepared in sequence for different mortar-sand particle size ratios and rubber contents, and the lateral confinement compression test is completed. It should be pointed out that two parallel tests are carried out under the same working conditions to ensure the repeatability of the test data.

[0044] S2. Based on the vertical stress-vertical strain data, a compression deformation prediction model of rubber sand mixed soil is constructed.

[0045] Based on the basic principles of soil mechanics, combined with the vertical stress-vertical strain data obtained in step S1, the porosity ratio of rubber-sand mixed soil under different vertical stresses is derived, and the individual and coupled effects of the mortar particle size ratio, rubber content, and vertical stress are considered to determine the form of the compression deformation prediction model of the rubber-sand mixed soil. Based on the test data, when constructing the porosity ratio and vertical pressure curve, the porosity ratio under 12.5kPa vertical stress and the vertical stress under 100kPa are used as references, and the rubber sand porosity ratio-vertical stress data are normalized; at the same time, the normalized vertical stress is logarithmically transformed to obtain the linear relationship between the normalized porosity ratio and the normalized and logarithmically processed vertical stress; finally, the optimal value of the unknown parameter is determined according to the least squares method, so as to construct a prediction model for the compression deformation of the rubber-sand mixed soil.

[0046] The specific steps include:

[0047] Step 2.1: The high elasticity and irregular shape of rubber particles make it difficult to accurately measure the initial void ratio e0 of the rubber-sand mixed soil under 0 kPa vertical stress. Therefore, the void ratio e0 of the rubber-sand mixed soil under 12.5 kPa vertical stress is used. 12.5 As the initial void ratio. The vertical strain ε of rubber sand mixed soil and the void ratio e under any vertical stress condition i The relationship is shown in Formula 1:

[0048]

[0049] Step 2.2: By trying different data processing methods, it is found that the void ratio e of the rubber sand mixed soil under different vertical stresses i And the corresponding working condition e 12.5 The modified porosity ratio e i / e 12.5 , and the modified vertical stress σ v / σ r (σr As the reference stress, 100 kPa is taken) there is a good logarithmic linear relationship between them, and the results are as follows Figure 2 As shown, its expression is shown in formula 2:

[0050]

[0051] Step 2.3: Substituting formula 2 into formula 1, the form of the vertical strain prediction model of rubber-sand mixed soil (initial model) can be constructed, as shown in formula 3; there is a significant linear relationship between the two unknown coefficients α and β and the rubber content RC, as shown in formulas 4 and 5; it can be seen that there is a correlation between the mortar-sand particle size ratio SR and the coefficients k1 and k2. Based on the goodness of fit, the optimal function expression and coefficients of the two unknown coefficients are determined. The results are shown in Figure 3 and Figure 4 Its expressions are shown in equations 6 and 7.

[0052]

[0053] α=a+k1·RC (4)

[0054] β=b+k2·RC (5)

[0055] k1=c·SR d (6)

[0056] k2=e·SR f (7)

[0057] The symbols a, b, c, d, e, and f represent the fitting parameters in the above formulas 4 to 7.

[0058] Step 2.4: Substitute the fitting result into Formula 3 to obtain the compression deformation prediction model of rubber sand mixed soil proposed in this embodiment. Its expression is as follows:

[0059]

[0060] In the above formula, the units of rubber content and vertical strain are both %. Further observation of formula 8 shows that for rubber-sand mixed soil with known mortar-sand particle size ratio and content, its vertical strain ε under specific vertical stress conditions is also related to the porosity ratio e of the mixed soil under 12.5 kPa vertical stress. 12.5 About. About 12.5 , can be determined by the following steps according to the importance of the project:

[0061] (1) Conduct a confined compression test on a rubber-sand mixture under a vertical stress of 12.5 kPa. The vertical strain, sample height, and initial void ratio e0 can be accurately determined.

[0062] (2) Compared with the strain of the mixed soil caused by the large vertical stress, the strain of the mixed soil under the 12.5 kPa vertical stress is smaller, and its change on the porosity of the mixed soil is also smaller. Therefore, it can be assumed that e 12.5 It is approximately equal to the initial porosity ratio e0, which can be determined based on the basic physical properties and relative density of the rubber sand mixed soil.

[0063] It should be noted that this model is obtained based on the results of the lateral confinement compression test of rubber-sand mixed soil under specific working conditions, and its restriction conditions are as follows:

[0064] (1) The mortar particle size ratio SR is between 0.1 and 3.0. During the derivation and verification of the formula, it was found that when SR is too small, the prediction ability of the formula is poor, but when the particle size ratio exceeds 3.0, it still has a high prediction accuracy;

[0065] (2) The rubber particle content is between 0 and 0.5, and the value of RC in the formula cannot be 0 or 1.0;

[0066] (3) The maximum vertical stress shall not exceed 400 kPa.

[0067] S3. Use the compression deformation prediction model to complete the compression deformation prediction of rubber sand mixed soil.

[0068] Embodiment 2

[0069] In order to verify the accuracy of the present invention, this embodiment is specially set up as a comparative verification experiment.

[0070] First, the test data of the present invention is used for self-verification. It should be noted that when using formula 8 for prediction, e is set 12.5 The value of is equal to the initial porosity ratio e0 (the same below), so under the action of 12.5kPa vertical stress, the predicted vertical strain value of the rubber sand is 0. The results are shown in Figure 5 As shown in the figure, it is found that the predicted value and the experimental value are generally in good agreement, which can accurately reflect the changes of the vertical strain of rubber-sand mixed soil with the mortar-sand particle size ratio, rubber content and vertical stress.

[0071] Subsequently, the reliability and applicability of the present invention were further verified by using three existing test data on the consolidation compression characteristics of rubber sand. The basic physical properties of the rubber sand mixed soil used in each study were obtained from these three tests, and the vertical stress-vertical strain results of the rubber sand mixed soil were predicted according to formula 8 and compared with the test values. The main parameters of the rubber sand mixed soil in the three tests are as follows:

[0072] (1) Zhang Yongfu et al. conducted confined compression tests on dry rubber sand. The particle size ratio of the rubber sand was 5.2, the initial porosity ratio was 0.4551, 0.5618, 0.6891, 0.7983, 0.9226 and 1.0022, the rubber mass fraction was 0, 10%, 20%, 30%, 40% and 50%, and the maximum vertical stress was 400 kPa.

[0073] (2) Won et al. conducted confined compression tests on dry rubber sand. The particle size ratios of the rubber sand were 0.44, 1.27, 1.87 and 4.0, the initial porosity ratios were: 0.7266, 1.0060, 1.1221 and 1.4040 (0.44); the initial porosity ratios were: 0.8696, 0.9894, 1.1310 and 1.2100 (1.27); the initial porosity ratios were 0.8371, 0.9320, 1.1591 and 1.2100 (1.87); the initial porosity ratios were 0.8236, 0.9423, 1.0046 and 1.2210 (4.0); the rubber mass fractions were 0, 10%, 20% and 40%, and the maximum vertical stress was 150 kPa.

[0074] (3) Badarayani et al. conducted confined compression tests on saturated rubber sand with different densities. The particle size ratio of the rubber sand was 1.0, the initial porosity ratio was 0.65 and 0.75, the rubber mass fraction was 0, 4.2%, 9%, 11.6%, 14.4%, 20.7% and 28.2%, and the maximum vertical stress was 400 kPa.

[0075] According to formula 8, the vertical stress-vertical strain results of rubber sand mixed soil in three existing technologies are predicted and compared with the test values, such as Figure 6 to Figure 8 As shown. In general, the predicted value of the compression deformation of the rubber sand mixed soil obtained by the model proposed in the present invention is close to the experimental value, especially when the rubber particle size is large. The difference between the predicted value and the experimental value mainly comes from different test materials, hydraulic conditions, sample preparation density and methods, etc. By comparing the predicted value and the experimental value of the rubber sand mixed soil under multiple working conditions, the accuracy and reliability of the prediction method proposed in the present invention are verified.

[0076] Embodiment 3

[0077] The present invention also provides a rubber-sand mixed soil compression deformation prediction system, comprising: a test module, a construction module and a prediction module; the test module is used to obtain vertical stress-vertical strain data of the rubber-sand mixed soil under different working conditions through a side limit compression test of the rubber-sand mixed soil; the construction module is used to construct a compression deformation prediction model of the rubber-sand mixed soil based on the vertical stress-vertical strain data; the prediction module is used to complete the compression deformation prediction of the rubber-sand mixed soil using the compression deformation prediction model.

[0078] The following will explain in detail how the present invention solves technical problems in real life in conjunction with this embodiment.

[0079] First, the test module conducts a lateral confined compression test on the rubber-sand mixed soil to obtain the vertical stress-vertical strain data of the rubber-sand mixed soil under different working conditions.

[0080] In this embodiment, when conducting the confined compression test, Fujian standard sand and rubber particle materials with the same non-uniformity coefficient are selected, and rubber sand mixed soil with different rubber sand particle size ratios and rubber contents are prepared according to the rubber mass ratio for rubber particles with different median particle sizes. Confined compression tests are carried out under different vertical stress conditions to obtain vertical stress-vertical strain data of the rubber sand mixed soil under different working conditions.

[0081] The specific process includes the following:

[0082] Step 1.1: Selection of test equipment. The test data used in the compression deformation prediction method of rubber sand mixed soil constructed this time all come from the confined compression test of rubber sand mixed soil. The compression test uses a pneumatic double consolidation instrument, in which the sample box has a diameter of 100mm and a height of 50mm; the maximum vertical stress is 500kPa, and the displacement meter range is 25mm, which can realize automatic recording of test data.

[0083] Step 1.2: Preparation of rubber sand mixed soil samples and test plan. Fujian standard sand and rubber particles were used in this test. The mortar sand particle size ratios (SR) considered in the test were 0.1, 0.5, 1.0 and 3.0, and the rubber content (mass ratio, RC) were 0% (pure sand), 5%, 10%, 20%, 30% and 50%, respectively. According to the relevant geotechnical test procedures, the maximum and minimum dry densities of rubber sand mixed soil under different mortar sand particle size ratios and rubber content conditions were determined. According to the test conditions, the sand particles and rubber particles were fully mixed, vibrated and compacted to the predetermined height in three layers to prepare a medium-dense sample with a relative density of 70%.

[0084] Step 1.3: Apply a sequence of vertical loads. The load sequence applied in the lateral confinement compression test is 12.5, 25, 50, 100, 150, 200, 300, and 400 kPa. After the deformation of the rubber-sand mixed soil sample reaches a stable state under each level of load, start applying the next level of load, and apply the load step by step. After all loads are applied, stop loading, and check and process the test data. According to the test plan, samples are prepared in sequence for different mortar-sand particle size ratios and rubber contents, and the lateral confinement compression test is completed. It should be pointed out that two parallel tests are carried out under the same working conditions to ensure the repeatability of the test data.

[0085] The construction module constructs a compression deformation prediction model for rubber-sand mixed soil based on vertical stress-vertical strain data.

[0086] Based on the basic principles of soil mechanics, combined with the vertical stress-vertical strain data obtained in step S1, the porosity ratio of rubber-sand mixed soil under different vertical stresses is derived, and the individual and coupled effects of the mortar particle size ratio, rubber content, and vertical stress are considered to determine the form of the compression deformation prediction model of the rubber-sand mixed soil. Based on the test data, when constructing the porosity ratio and vertical pressure curve, the porosity ratio under 12.5kPa vertical stress and the vertical stress under 100kPa are used as references, and the rubber sand porosity ratio-vertical stress data are normalized; at the same time, the normalized vertical stress is logarithmically transformed to obtain the linear relationship between the normalized porosity ratio and the normalized and logarithmically processed vertical stress; finally, the optimal value of the unknown parameter is determined according to the least squares method, so as to construct a prediction model for the compression deformation of the rubber-sand mixed soil.

[0087] The specific process includes the following:

[0088] Step 2.1: The high elasticity and irregular shape of rubber particles make it difficult to accurately measure the initial void ratio e0 of the rubber-sand mixed soil under 0 kPa vertical stress. Therefore, the void ratio e0 of the rubber-sand mixed soil under 12.5 kPa vertical stress is used. 12.5 As the initial void ratio. The vertical strain ε of rubber sand mixed soil and the void ratio e under any vertical stress condition i The relationship is shown in Formula 1:

[0089]

[0090] Step 2.2: By trying different data processing methods, it is found that the void ratio e of the rubber sand mixed soil under different vertical stresses i And the corresponding working condition e 12.5 The modified porosity ratio e i / e 12.5 , and the modified vertical stress σ v / σ r (σ r As the reference stress, 100 kPa is taken) there is a good logarithmic linear relationship between them, and the results are as follows Figure 2 As shown, its expression is shown in formula 2:

[0091]

[0092] Step 2.3: Substituting formula 13 into formula 12, the form of the vertical strain prediction model of rubber-sand mixed soil (initial model) can be constructed, as shown in formula 14; there is a significant linear relationship between the two unknown coefficients αα and β and the rubber content RC, as shown in formulas 15 and 16; it can be seen that there is a correlation between the mortar-sand particle size ratio SR and the coefficients k1 and k2. Based on the goodness of fit, the optimal function expression and coefficients of the two unknown coefficients are determined. The results are shown in Figure 3 and Figure 4 Its expressions are shown in equations 17 and 18.

[0093]

[0094] α=a+k1·RC (15)

[0095] β=b+k2·RC (16)

[0096] k1=c·SR d (17)

[0097] k2=e·SR f (18)

[0098] Wherein a, b, c, d, e, and f represent the fitting parameters in the above formulas 15 to 18.

[0099] Step 2.4: Substitute the fitting result into formula 14 to obtain the compression deformation prediction model of rubber sand mixed soil proposed in this embodiment. Its expression is as follows:

[0100]

[0101] In the above formula, the units of rubber content and vertical strain are both %. Further observation of formula 19 shows that for rubber-sand mixed soil with known mortar-sand particle size ratio and content, its vertical strain ε under specific vertical stress conditions is also related to the porosity ratio e of the mixed soil under 12.5 kPa vertical stress. 12.5 About. About 12.5 , can be determined by the following steps according to the importance of the project:

[0102] (1) Conduct a confined compression test on a rubber-sand mixture under a vertical stress of 12.5 kPa. The vertical strain, sample height, and initial void ratio e0 can be accurately determined.

[0103] (2) Compared with the strain of the mixed soil caused by the large vertical stress, the strain of the mixed soil under the 12.5 kPa vertical stress is smaller, and its change on the porosity of the mixed soil is also smaller. Therefore, it can be assumed that e 12.5 It is approximately equal to the initial porosity ratio e0, which can be determined based on the basic physical properties and relative density of the rubber sand mixed soil.

[0104] It should be noted that this model is obtained based on the results of the lateral confinement compression test of rubber-sand mixed soil under specific working conditions, and its restriction conditions are as follows:

[0105] (1) The mortar particle size ratio SR is between 0.1 and 3.0. During the derivation and verification of the formula, it was found that when SR is too small, the prediction ability of the formula is poor, but when the particle size ratio exceeds 3.0, it still has a high prediction accuracy;

[0106] (2) The rubber particle content is between 0 and 0.5, and the value of RC in the formula cannot be 0 or 1.0;

[0107] (3) The maximum vertical stress shall not exceed 400 kPa.

[0108] The prediction module uses the compression deformation prediction model to complete the compression deformation prediction of rubber sand mixed soil.

[0109] The embodiments described above are only descriptions of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for predicting compression deformation of rubber-sand mixed soil, characterized in that the steps include: Through the confined compression test of rubber-sand mixed soil, the vertical stress-vertical strain data of rubber-sand mixed soil under different working conditions are obtained; Based on the vertical stress-vertical strain data, a compression deformation prediction model of rubber-sand mixed soil is constructed; The compression deformation prediction model is used to complete the compression deformation prediction of rubber-sand mixed soil.

2. The method for predicting compression deformation of rubber-sand mixed soil according to claim 1, characterized in that: When conducting the lateral confined compression test, experimental materials with the same non-uniformity coefficient are selected, including sand materials and rubber particle materials; for rubber particles with different median particle sizes, rubber-sand mixed soils with different mortar-sand particle size ratios and rubber contents are prepared according to the rubber mass ratio; lateral confined compression tests are carried out under different vertical stress conditions to obtain the vertical stress-vertical strain data of the rubber-sand mixed soil under different working conditions.

3. The method for predicting compression deformation of rubber-sand mixed soil according to claim 1, characterized in that: Based on the basic principles of soil mechanics and the obtained vertical stress-vertical strain data, the void ratio of the rubber-sand mixed soil under different vertical stresses is derived, and the initial model is determined based on the individual and coupled effects of the mortar-sand particle size ratio, rubber content, and vertical stress; Based on the test data, data normalization, logarithmic transformation and least square method are used to determine the optimal values ​​of the undetermined parameters in the initial model, so as to construct a compression deformation prediction model of rubber-sand mixed soil.

4. The method for predicting compression deformation of rubber-sand mixed soil according to claim 3, characterized in that: The compression deformation prediction model constructed includes: Where, ε represents the vertical strain; e 12.5 represents the void ratio of the mixed soil under 12.5 kPa vertical stress; SR represents the mortar-sand particle size ratio; RC represents the rubber content; σ v represents vertical stress; σ r represents the reference vertical stress.

5. A system for predicting compression deformation of rubber-sand mixed soil, the system being used to implement the method according to any one of claims 1 to 4, characterized in that: include: Experimental module, construction module and prediction module; The test module is used to obtain vertical stress-vertical strain data of the rubber-sand mixed soil under different working conditions through a confined compression test of the rubber-sand mixed soil; The construction module is used to construct a compression deformation prediction model of rubber-sand mixed soil based on the vertical stress-vertical strain data; The prediction module is used to complete the compression deformation prediction of rubber-sand mixed soil using the compression deformation prediction model.

6. The rubber-sand mixed soil compression deformation prediction system according to claim 5 is characterized in that: When conducting the lateral confined compression test, experimental materials with the same non-uniformity coefficient are selected, including sand materials and rubber particle materials; for rubber particles with different median particle sizes, rubber-sand mixed soils with different mortar-sand particle size ratios and rubber contents are prepared according to the rubber mass ratio; lateral confined compression tests are carried out under different vertical stress conditions to obtain the vertical stress-vertical strain data of the rubber-sand mixed soil under different working conditions.

7. The rubber-sand mixed soil compression deformation prediction system according to claim 5 is characterized in that: The workflow of the construction module includes: based on the basic principles of soil mechanics, combined with the acquired vertical stress-vertical strain data, the porosity ratio of the rubber-sand mixed soil under different vertical stresses is derived, and the initial model is determined based on the individual and coupled effects of the mortar-sand particle size ratio, rubber content, and vertical stress; based on the test data, the optimal values ​​of the unknown parameters in the initial model are determined by data normalization, logarithmic transformation, and least squares method, so as to construct a compression deformation prediction model for the rubber-sand mixed soil.

8. The rubber-sand mixed soil compression deformation prediction system according to claim 7 is characterized in that: The compression deformation prediction model constructed includes: Where, ε represents the vertical strain; e 12.5 represents the void ratio of the mixed soil under 12.5 kPa vertical stress; SR represents the mortar-sand particle size ratio; RC represents the rubber content; σ v represents vertical stress; σ r represents the reference vertical stress.

Images