A method and system for predicting compression deformation of rubber sand mixed soil

Abstract

The present invention discloses a method and system for predicting the compression deformation of a rubber-sand mixture. The method comprises: obtaining vertical stress-vertical strain data of the rubber-sand mixture under different working conditions through a confined compression test of the rubber-sand mixture; constructing a compression deformation prediction model for the rubber-sand mixture based on the vertical stress-vertical strain data; and using the compression deformation prediction model to complete the compression deformation prediction of the rubber-sand mixture. The present invention proposes a compression deformation prediction model for a rubber-sand mixture with few parameters, high accuracy, and convenient engineering application. The present invention can be used to guide the design of rubber sand backfill compaction parameters, predict the service life settlement of rubber sand backfill structures, etc., and help promote the resource utilization of waste rubber particles in the fields of geotechnical engineering, roads, and underground engineering.

Description

Technical Field

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

[0002] Insufficient recycling of waste tires results in serious resource waste and environmental pollution. Therefore, accelerating the green and resource-based large-scale utilization of waste tires in civil engineering is urgent. Research has shown that rubber-sand mixtures, formed by mixing rubber particles from crushed waste tires with natural sand in a certain proportion, exhibit low density, low modulus, high damping, high shear strength, and good permeability. They are a new, green, low-cost geotechnical composite material that can be used as backfill material for roadbeds, underground structures, retaining walls, and foundations. This reduces the weight of the backfill, reduces settlement of weak roadbeds, lowers soil pressure, and provides vibration isolation and seismic isolation.

[0003] However, when rubber sand is backfilled into a structure, the high-elasticity and low-modulus rubber particles may produce excessive deformation, compromising the service safety of the structure. Therefore, a reasonable estimation of the compression deformation of rubber sand mixed soil is of great significance 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 aggregate for local backfill to reduce the load, and their compression deformation characteristics were widely studied. However, large-scale backfilling of pure rubber strips or coarse aggregate can easily lead to excessive surface or structural settlement and easily cause fires. Therefore, mixing with natural soil in an appropriate proportion can effectively solve the above problems. At present, there are relatively few studies on the compression deformation of rubber sand mixed soil, and there are no reports on compression deformation prediction methods that consider the influence of rubber content and particle size, which is not conducive to its engineering application. Summary of the Invention

[0004] In response to 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, comprising the following steps:

[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 the 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 combined with the obtained 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 experimental 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 constructed compression deformation prediction model 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, which is used to implement the above method and includes: 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 ratio of the rubber-sand mixture under different vertical stresses, and determining the initial model based on the individual and coupled effects of the mortar-sand particle size ratio, rubber content, and vertical stress; based on the experimental 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 mixture.

[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 lateral confined compression test data. The test plan 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 few parameters, has clear physical meanings, and can all be determined by experiments, which facilitates 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 any creative work.

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

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

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

[0029] Figure 4 1 is a curve showing the relationship between the coefficients k1 and k2 and the mortar particle size ratio SR according to an embodiment of the present invention; wherein (a) shows the curve showing the relationship between the 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 values ​​of the embodiment of the present invention and the predicted values ​​of this method;

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

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

[0033] Figure 8 1 is a comparison of the experimental 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 working condition of e0=0.65; (b) represents the comparison under the working condition of e0=0.75. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts 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] Example 1

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

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

[0039] In this example, confined compression tests were conducted using Fujian standard sand and rubber particles with the same heterogeneity coefficient. Rubber-sand mixtures with varying mortar-sand particle size ratios and rubber contents were prepared based on the rubber mass ratio, using rubber particles with varying median particle sizes. Confined compression tests were conducted under varying vertical stress conditions to obtain vertical stress-strain data for the rubber-sand mixtures under different working conditions.

[0040] The specific steps include:

[0041] Step 1.1: Test Equipment Selection. The test data used in this proposed compression deformation prediction method for rubber-sand mixtures was derived entirely from confined compression tests of rubber-sand mixtures. The compression tests were conducted using a pneumatic double-particle oedometer with a specimen box of 100 mm in diameter and 50 mm in height. The maximum vertical stress was 500 kPa, and the displacement meter had a range of 25 mm, enabling 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, respectively, 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 the 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-density 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 inspect 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 for rubber-sand mixture was constructed.

[0045] Based on the basic principles of soil mechanics and the vertical stress-vertical strain data obtained in step S1, the void ratio of the rubber-sand mixture under different vertical stresses was derived. The individual and coupled effects of the mortar-sand particle size ratio, rubber content, and vertical stress were considered to determine the form of the compression deformation prediction model for the rubber-sand mixture. Based on the experimental data, when constructing the void ratio and vertical pressure curves, the void ratio under a vertical stress of 12.5 kPa and the vertical stress under 100 kPa were used as references, and the rubber-sand void ratio-vertical stress data were normalized. Simultaneously, the normalized vertical stress was logarithmically transformed to obtain a linear relationship between the normalized void ratio and the normalized and logarithmized vertical stress. Finally, the optimal values ​​of the undetermined parameters were determined using the least squares method, thereby constructing a prediction model for the compression deformation of the rubber-sand mixture.

[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 mixture under 0 kPa vertical stress. Therefore, the void ratio e0 of the rubber-sand mixture under 12.5 kPa vertical stress is used. 12.5 As the initial porosity ratio. The vertical strain ε of rubber sand mixed soil and the porosity 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, take 100kPa) 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: Substitute Formula 2 into Formula 1 to construct the form of the vertical strain prediction model of rubber-sand mixed soil (initial model), 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, and the results are shown as follows: 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] The units of rubber content and vertical strain in the above formula 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 e 12.5 , can be determined by the following steps based on 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 mixed soil caused by large vertical stress, the strain of mixed soil under 12.5 kPa vertical stress is smaller, and its change on the porosity of 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 confined compression test of rubber-sand mixed soil under specific working conditions, and its constraints 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 the 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 does not exceed 400kPa.

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

[0068] Example 2

[0069] In order to verify the accuracy of the present invention, this embodiment is 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 vertical strain prediction value of the rubber sand is 0. Figure 5 As shown in the figure, it is found that the predicted values ​​are in good agreement with the experimental values, and 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 this invention were further verified using data from three existing tests on the consolidation and compression characteristics of rubber sand. The basic physical properties of the rubber sand mixtures used in each study were obtained from these three tests. Based on Equation 8, the vertical stress-vertical strain results of the rubber sand mixtures were predicted and compared with the experimental values. The main parameters of the rubber sand mixtures used in the three tests are as follows:

[0072] (1) Zhang Yongfu et al. conducted confined compression tests on dry rubber sand. The test results were as follows: the particle size ratio of the rubber sand was 5.2, the initial porosity ratios were 0.4551, 0.5618, 0.6891, 0.7983, 0.9226, and 1.0022, the rubber mass fractions were 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 test results were as follows: the saturated rubber sand particle size ratio 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 the rubber sand mixed soil in the three existing technologies are predicted and compared with the test values, such as Figures 6 to 8 As shown in the figure, the predicted compression deformation values ​​of rubber-sand mixtures obtained using the proposed model are relatively close to the experimental values, especially when the rubber particle size is large. The discrepancies between the predicted and experimental values ​​are primarily due to differences in test materials, hydraulic conditions, sample preparation density, and method. Comparisons of predicted and experimental values ​​for rubber-sand mixtures under multiple working conditions validate the accuracy and reliability of the proposed prediction method.

[0076] Example 3

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

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

[0079] First, the test module obtains the vertical stress-vertical strain data of the rubber-sand mixed soil under different working conditions through the lateral confined compression test of the rubber-sand mixed soil.

[0080] In this example, confined compression tests were conducted using Fujian standard sand and rubber particles with the same heterogeneity coefficient. Rubber-sand mixtures with varying mortar-sand particle size ratios and rubber contents were prepared based on the rubber mass ratio, using rubber particles with varying median particle sizes. Confined compression tests were conducted under varying vertical stress conditions to obtain vertical stress-strain data for the rubber-sand mixtures under different working conditions.

[0081] The specific process includes the following:

[0082] Step 1.1: Test Equipment Selection. The test data used in this proposed compression deformation prediction method for rubber-sand mixtures was derived entirely from confined compression tests of rubber-sand mixtures. The compression tests were conducted using a pneumatic double-particle oedometer with a specimen box of 100 mm in diameter and 50 mm in height. The maximum vertical stress was 500 kPa, and the displacement meter had a range of 25 mm, enabling 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, respectively, 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 the 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-density 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 inspect 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 and the vertical stress-vertical strain data obtained in step S1, the void ratio of the rubber-sand mixture under different vertical stresses was derived. The individual and coupled effects of the mortar-sand particle size ratio, rubber content, and vertical stress were considered to determine the form of the compression deformation prediction model for the rubber-sand mixture. Based on the experimental data, when constructing the void ratio and vertical pressure curves, the void ratio under a vertical stress of 12.5 kPa and the vertical stress under 100 kPa were used as references, and the rubber-sand void ratio-vertical stress data were normalized. Simultaneously, the normalized vertical stress was logarithmically transformed to obtain a linear relationship between the normalized void ratio and the normalized and logarithmized vertical stress. Finally, the optimal values ​​of the undetermined parameters were determined using the least squares method, thereby constructing a prediction model for the compression deformation of the rubber-sand mixture.

[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 mixture under 0 kPa vertical stress. Therefore, the void ratio e0 of the rubber-sand mixture under 12.5 kPa vertical stress is used. 12.5 As the initial porosity ratio. The vertical strain ε of rubber sand mixed soil and the porosity 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, take 100kPa) 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 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, and the results are shown as follows: 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 the rubber-sand mixed soil proposed in this embodiment. Its expression is as follows:

[0100]

[0101] The units of rubber content and vertical strain in the above formula 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 e 12.5 , can be determined by the following steps based on 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 mixed soil caused by large vertical stress, the strain of mixed soil under 12.5 kPa vertical stress is smaller, and its change on the porosity of 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 confined compression test of rubber-sand mixed soil under specific working conditions, and its constraints 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 the 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 does not exceed 400kPa.

[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 merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined 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 the rubber-sand mixed soil is constructed; Based on the basic principles of soil mechanics and the obtained vertical stress-vertical strain data, the void ratio 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 undetermined parameters in the initial model, thereby constructing a compression deformation prediction model for rubber sand mixed soil; the constructed compression deformation prediction model 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; 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. 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 2, 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.

4. The rubber-sand mixed soil compression deformation prediction system according to claim 3, 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.

5. The rubber-sand mixed soil compression deformation prediction system according to claim 3, 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 mixture under different vertical stresses is deduced, 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 experimental data, the optimal values ​​of the undetermined parameters in the initial model are determined using data normalization, logarithmic transformation, and least squares method, thereby constructing a compression deformation prediction model for the rubber-sand mixture.

6. The rubber-sand mixed soil compression deformation prediction system according to claim 5, 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.

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