A prediction model for cumulative plastic strain of multi-stage loading of construction waste based on MICP, model construction method and prediction method

Abstract

The present invention relates to a prediction model for the cumulative plastic strain of multi-stage loading of construction waste based on MICP improvement, a method for constructing the model, and a prediction method. Based on the experimental results of the cumulative plastic strain of multi-stage loading, the present invention establishes a cumulative plastic strain prediction model that comprehensively considers factors such as calcium ion concentration, curing time, dynamic stress, matrix suction, and loading times. By introducing the coupling effect of multiple factors, the model effectively describes the strain evolution process of construction waste under different working conditions, thereby achieving an accurate prediction of the long-term deformation characteristics of the material. The establishment of a multi-stage loading cumulative plastic strain prediction model is of great significance for the performance evaluation and application optimization of engineering materials under different stress conditions. Through this prediction model, the mechanical properties of construction waste can be evaluated in advance, guiding the rational selection of materials in different application scenarios, and ensuring the long-term safety and stability of the structure.

Description

Technical Field

[0001] The present invention belongs to the technical field of waste building material recycling, and relates to a prediction model for multi-stage loading cumulative plastic strain of building waste based on MICP improvement, a model construction method, and a prediction method. Background Art

[0002] In the process of using MICP technology to improve construction waste, it is essential to conduct multi-stage loading cumulative plastic strain tests to fully understand its mechanical behavior under different load conditions. In actual engineering, construction waste needs to withstand various forms of external loads, including repeated dynamic loads and long-term static loads, and these loads are crucial to the accumulation of internal strain and plastic deformation of the material. Traditional single-load mechanical test methods are usually difficult to fully reflect the cumulative strain changes of materials under repeated loading and their final mechanical properties. By studying the deformation characteristics of MICP-modified construction waste through multi-stage loading cumulative plastic strain tests, we can systematically reveal the law of its performance evolution under long-term multiple loading conditions, thereby evaluating its stability and reliability under complex load conditions. This is not only of great significance for understanding the performance evolution law of MICP-modified construction waste, but also provides a scientific basis for further optimizing the application process of MICP modification technology.

[0003] To better implement the application of MICP-modified construction waste in engineering projects and ensure its stable performance under long-term loads, it is particularly necessary to establish a prediction model based on the cumulative plastic strain of multi-stage loading. The stress conditions of construction waste in actual engineering applications are complex. The evolution of cumulative plastic strain is not only closely related to the number of loading times, but is also affected by multiple factors such as calcium ion concentration, curing time, dynamic stress, and matrix suction. These factors are coupled with each other, resulting in the material's strain behavior being highly nonlinear and complex. Therefore, establishing a prediction model for the cumulative plastic strain of multi-stage loading not only helps to effectively predict the deformation trend of the material under multiple loading conditions, but also provides a scientific basis and technical support for the application design of MICP-modified construction waste in actual engineering projects. Through this prediction model, it is possible to achieve a quantitative evaluation of the modification effect of construction waste, thereby guiding its rational application in different engineering scenarios and ensuring the long-term performance and structural safety of the material.

[0004] In summary, research on the MICP technology for the modification of construction waste has significant engineering value and practical significance in the current context. By studying the cumulative plastic strain of construction waste under multi-stage loading, we can fully reveal the deformation patterns of MICP modification under different working conditions. The establishment of a corresponding cumulative plastic strain prediction model provides important theoretical support and technical guidance for practical engineering applications. This research not only provides a technical basis for the resource utilization of construction waste but also has a positive impact on promoting the green, environmentally friendly, and sustainable development of building materials. Summary of the Invention

[0005] To solve the above problems, the present invention provides a prediction model for the cumulative plastic strain of multi-stage loading of construction waste based on MICP improvement. The model is:

[0006]

[0007] Where:

[0008] C Ca 2+ is the calcium ion concentration; D m is the number of maintenance days; σ d is the dynamic loading stress; N is the number of cyclic loading; is the standard calcium ion concentration, which is 1 mol / L; e is a mathematical constant, which is 2.718; P a is the atmospheric pressure, which is 100kPa; is the matrix suction when water content = i; is the matrix suction when the water content is OMC; a, n, m are the parameters of the VAN-GENUCHTEN model; a1, a2, b1, b2, b3, b4, b5, b6, and b7 are model parameters.

[0009] This application also provides a method for constructing a model, the specific steps are as follows:

[0010] Step (1) selecting construction waste materials for crushing and screening, and conducting a system basic physical property test; based on the above basic physical property test, measuring the soil-water characteristic curve of the construction waste and determining the water absorption characteristics of the construction waste under different water content states;

[0011] Step (2) adding equal volumes of MICP improvement reaction solutions of different concentrations to the sample and mixing thoroughly;

[0012] Step (3) forming the sample prepared in step (2) into a cylindrical sample and compacting it, and then curing it under different time conditions;

[0013] Step (4) Dynamic triaxial test

[0014] The multi-stage loading cumulative plastic strain test method was adopted, and a total of 4 stress levels were designed for the multi-stage loading permanent deformation test. The multi-stage loading cumulative plastic strain test results under different conditions were then obtained.

[0015] Step (5) Based on the results of step (1) and step (4), construct a comprehensive consideration of C Ca 2+ 、D m , σ d , ω, N multi-stage loading cumulative plastic strain prediction model;

[0016] The model is:

[0017]

[0018] Where:

[0019] C Ca 2+ is the calcium ion concentration; D m is the number of maintenance days; σ d is the dynamic loading stress; N is the number of cyclic loading; is the standard calcium ion concentration, which is 1 mol / L; e is a mathematical constant, which is 2.718; P a is the atmospheric pressure, which is 100kPa; is the matrix suction when water content = i; is the matrix suction when the water content is OMC; a, n, m are the parameters of the VAN-GENUCHTEN model; a1, a2, b1, b2, b3, b4, b5, b6, and b7 are model parameters.

[0020] On the basis of the above scheme, in step (1), the VAN-GENUCHTEN model is used to determine the water absorption characteristics of construction waste under different water content states.

[0021] Based on the above scheme, in step (2), C in the reaction solution Ca 2+ The concentrations were set to 0 mol / L, 0.5 mol / L, 1 mol / L, and 2 mol / L, and the bacteria used in the reaction solution was Sporosarcina pasteurianus.

[0022] On the basis of the above scheme, in step (4), during the test, the confining pressure is set to 30 kPa, the dynamic loading stress is set to 15 kPa, 30 kPa, 45 kPa, and 60 kPa, respectively, the number of loading times for each level is 10,000 times, the loading frequency is 1 Hz, the loading time is 0.1 s, and the intermittent time is 0.9 s.

[0023] The present application also provides a method for predicting the cumulative plastic strain of multi-stage loading of construction waste based on MICP improvement, using the above-mentioned model.

[0024] Based on the experimental results of multi-stage loading cumulative plastic strain, the present invention establishes a cumulative plastic strain prediction model that comprehensively considers factors such as calcium ion concentration, curing time, dynamic stress, matrix suction and loading times. By introducing the coupling effect of multiple factors, the model effectively describes the strain evolution process of construction waste under different working conditions, thereby achieving accurate prediction of the long-term deformation characteristics of the material. The composition of construction waste is complex and the performance varies greatly. Its stress state under actual working conditions has highly complex and nonlinear characteristics. Therefore, the establishment of a multi-stage loading cumulative plastic strain prediction model is of great significance for the performance evaluation and application optimization of engineering materials under different stress conditions. Through this prediction model, the mechanical properties of construction waste can be evaluated in advance, the rational selection of materials in different application scenarios can be guided, the long-term safety and stability of the structure can be ensured, and the efficient, green and sustainable utilization of construction waste can be achieved.

[0025] This invention, through the application of MICP technology to improve construction waste, not only significantly enhances the mechanical properties and stability of the material, but also, through multi-stage loading cumulative plastic strain testing and the development of a predictive model, comprehensively reveals the strain evolution of the modified material under complex loading conditions, providing a scientific basis and technical guidance for its application in practical engineering projects. This invention provides an innovative solution for the resource utilization of construction waste, has significant social, economic, and environmental value, and meets the technical requirements for sustainable development in modern civil engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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.

[0027] Figure 1 The results of the screening test of construction waste in Example 2 are as follows;

[0028] Figure 2 Filter paper method determination results of construction waste;

[0029] Figure 3 C Ca 2+ =0mol / L, D m=0, σ3 = 30kPa, the results of multi-stage loading cumulative plastic strain tests corresponding to different ω (0.9OMC, OMC, 1.1OMC);

[0030] Figure 4 ω=OMC,D m =0, 6, σ3 = 30kPa, different C Ca 2+ (0mol / L, 0.5mol / L, 1mol / L and 2mol / L) corresponding multi-level loading cumulative plastic strain test results;

[0031] Figure 5 C Ca 2+ =0, 1mol / L, ω = OMC, σ3 = 30kPa, different D m (0, 1, 3, 6, 10) corresponding to the multi-level loading cumulative plastic strain test results;

[0032] Figure 6 Robustness verification diagram of the newly built model; DETAILED DESCRIPTION

[0033] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described 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.

[0034] Example 1

[0035] The present invention provides a prediction model for the cumulative plastic strain of multi-stage loading of construction waste based on MICP improvement, wherein the model is:

[0036]

[0037] Where:

[0038] C Ca 2+ is the calcium ion concentration; D m is the number of maintenance days; σ d is the dynamic loading stress; N is the number of cyclic loading; is the standard calcium ion concentration, which is 1 mol / L; e is a mathematical constant, which is 2.718; P a is the atmospheric pressure, which is 100kPa; is the matrix suction when water content = i; is the matrix suction when the water content is OMC; a, n, m are the parameters of the VAN-GENUCHTEN model; a1, a2, b1, b2, b3, b4, b5, b6, and b7 are model parameters.

[0039] The construction method of the above model is:

[0040] Step (1) selecting construction waste materials for crushing and screening, and conducting a system basic physical property test; based on the above basic physical property test, the soil-water characteristic curve of the construction waste is measured and the VAN-GENUCHTEN model is used to determine the water absorption characteristics of the construction waste under different water content states;

[0041] Step (2) adding equal volumes of MICP improvement reaction solutions of different concentrations to the sample and mixing thoroughly; C in the reaction solution Ca 2+ The concentrations were set to 0 mol / L, 0.5 mol / L, 1 mol / L, and 2 mol / L, and the bacteria used in the reaction solution was Sporosarcina pasteurianus.

[0042] Step (3) forming the sample prepared in step (2) into a cylindrical sample and compacting it, and then curing it under different time conditions;

[0043] Step (4) Dynamic triaxial test

[0044] A multi-stage loading cumulative plastic strain test method was adopted, and a total of four stress levels were designed for the multi-stage loading permanent deformation test. Then, the multi-stage loading cumulative plastic strain test results under different conditions were obtained. During the test, the confining pressure was set to 30 kPa, and the dynamic loading stresses were set to 15 kPa, 30 kPa, 45 kPa, and 60 kPa, respectively. The number of loading times at each level was 10,000, the loading frequency was 1 Hz, the loading time was 0.1 s, and the rest time was 0.9 s.

[0045] Step (5) Based on the results of step (1) and step (4), construct a comprehensive consideration of C Ca 2+ 、D m , σ d , ω, and N multi-level loading cumulative plastic strain prediction model.

[0046] Example 2

[0047] The embodiment of the present invention provides a method for predicting the cumulative plastic strain of construction waste using multi-stage loading improved by MICP technology. The specific process is as follows:

[0048] Step a: The construction waste materials selected in this example are demolition waste from a construction site in Changsha City, and are crushed and screened to ensure that they meet the test requirements. The main components of the waste include concrete, masonry, and mortar blocks, with their respective mass proportions being 45.2%, 15.3%, and 39.5%, respectively. The particle size distribution curve of the material is shown in Figure 1. Figure 1 In order to gain a deeper understanding of the basic physical characteristics of these construction wastes, a systematic physical performance test was carried out.

[0049] The test results show that the organic matter content of the construction waste is 1.9%, the soluble salt content is 0.38%, and the content of other impurities is 0.9%. These indicators show that there are a small amount of organic impurities and soluble salts in the material, which may affect its durability and stability in actual engineering. In addition, the liquid limit and plastic limit of the material are 28% and 22% respectively, which indicates that it has a certain plasticity but not significant, and may show limited deformation ability when sheared. The maximum dry density of the material is 1.84g / cm 3 , the optimum moisture content (OMC) is 14.8%, indicating that the best compaction effect can be achieved under this moisture state.

[0050] Based on the above research on basic physical properties, the filter paper method that complies with the ASTM D5298-10 specification was selected to measure the soil-water characteristic curve (SWCC) of construction waste.

[0051] The filter paper method is a commonly used and effective method for measuring matrix suction. It is suitable for testing various types of soils and fillers and is characterized by its ease of operation and wide measurement range. In order to further quantify the water absorption characteristics of construction waste under different water content conditions, this example uses the VAN-GENUCHTEN model to fit and describe its soil-water characteristic curve. This model is a typical unsaturated soil characteristic model that can accurately fit the water absorption characteristics of construction waste. The fitting results are shown in Figure 2. Figure 2 shown.

[0052] Step b: Based on the reaction mechanism of MICP, the reaction solution consists of bacterial solution and cementing solution. The basic reaction equations are shown in formulas (1) to (3):

[0053]

[0054] Ca 2+ +Cell——→Cell-Ca 2+ (2)

[0055] Cell-Ca 2+ +CO3 2- ——→Cell-CaCO3↓ (3)

[0056] In an alkaline environment, bacteria secrete urease through metabolic activities, which can continuously catalyze the hydrolysis of urea to produce ammonium ions (NH4 + ) and carbonate ions (CO3 2- ), as shown in formula (1). At the same time, since the bacterial cell surface has a negative charge, it can attract calcium ions (Ca 2+ ), which then combines with carbonate ions to form cementing calcium carbonate crystals, as described in equations (2) and (3). In this process, bacteria are not only responsible for urease production and urea hydrolysis, but also serve as the core attachment point for calcium carbonate precipitation. Therefore, cultivating a highly active bacterial solution is a key step in implementing MICP technology.

[0057] To this end, the present invention selected the environmentally friendly and non-toxic Sporosarcina pasteurii (CGMCC 1.3687) as the bacterial strain. To achieve bacterial activation and large-scale culture, the present invention selected NH4-YE liquid culture medium, specifically comprising 21g / L yeast extract, 9g / L ammonium chloride (NH4Cl), 23mg / L nickel chloride hexahydrate (NiCl2·6H2O), 11mg / L manganese sulfate tetrahydrate (MnSO4·4H2O), and 1L pure water. These ingredients provide the bacteria with sufficient nutrition, particularly nitrogen and trace elements, to promote rapid bacterial growth and the secretion of urease.

[0058] After the culture medium is prepared, it is dispensed into sterile containers and sterilized with high-pressure steam at 121°C for 20 minutes to ensure the sterility of the culture medium and prevent contamination from affecting the culture. After the sterilized culture medium cools to room temperature, the activated bacteria are aseptically inoculated at a ratio of 1:100. The inoculated culture is placed in a constant temperature shaking incubator and incubated continuously at 30°C and 150 rpm for 20 hours to obtain sufficient bacteria with high activity.

[0059] After the bacterial culture was completed, the optical density (OD 600 ) is used to evaluate the growth concentration of the bacterial solution. In this experiment, the bacterial solution OD 600 The urease activity in the bacterial solution was measured using a DDS-11A conductivity meter. The urease activity was calculated using the empirical formula of Whiffin et al., converting the change in conductivity into the amount of urea hydrolyzed per unit time. In this experiment, the measured urease activity was 15.4 μmol of urea per minute, demonstrating high biocatalytic capacity.

[0060] In addition, to ensure the effective precipitation of calcium carbonate during the MICP process, a mixed cementing fluid consisting of calcium chloride (CaCl2) and urea was selected in this experiment. CaCl2, as a calcium source, provides sufficient calcium ions (Ca 2+ During bacterial metabolism, urea not only provides a nitrogen source but also hydrolyzes under the action of urease to produce carbonate ions, which combine with calcium ions to form calcium carbonate precipitates. This process plays a vital role in cementing and strengthening porous media, effectively improving their strength and stability.

[0061] Step c:

[0062] (a) MICP treatment of construction waste

[0063] The optimal moisture content of the sample is determined by the compaction test results, and the MICP reaction solution is prepared according to the above steps. Ca 2+ Set to 0mol / L, 0.5mol / L, 1mol / L and 2mol / L. Add equal volumes of the prepared reaction solution (same volume of 0.9OMC, OMC, 1.1OMC) to the sample and stir thoroughly to ensure that the microorganisms and Ca 2+ uniform contact between particles.

[0064] (b) Sample preparation and curing

[0065] Cylindrical specimens with a diameter of 101 mm and a height of 200 mm were prepared using a standard split mold and compacted to 95% of the maximum dry density of the specimen as determined by the compaction test results. Then, to ensure the effectiveness of the MICP treatment, the specimens were immediately placed in a constant temperature and humidity curing box (the curing temperature was set at 25°C) after preparation. m Effect of MICP treatment on the effect of D m The settings for increasing the backward difference are 0, 1, 3, 6, and 10 days.

[0066] (c) Develop a dynamic triaxial test plan

[0067] In the traditional single-stage dynamic triaxial test, each specimen only considers a single stress loading mode, that is, only one confining pressure and one level of dynamic loading stress can be loaded each time. If the multi-level dynamic loading stress in the actual project is to be simulated, a large number of specimens need to be made, which is not only time-consuming and labor-intensive, but also costly, and does not conform to the continuous loading stress state actually suffered by the roadbed, and also fails to reflect the actual situation of increasing axle loads. To this end, the present invention designs a multi-level loading cumulative plastic strain test method. Considering that the cumulative strain caused by the smaller stress in the early stage has a smaller effect on the cumulative strain caused by the larger stress in the later stage, but the larger amplitude dynamic load will change the cumulative strain caused by the subsequent small stress, the multi-level loading permanent deformation test is designed with 4 levels of stress levels. Among them, the confining pressure is set to 30kPa, and the dynamic loading stress is set to 15kPa, 30kPa, 45kPa, and 60kPa respectively according to the stress ratio (0.5, 1, 1.5, 2). The number of loading times at each level is 10,000 times, the loading frequency is 1Hz, the loading time is 0.1s, and the rest time is 0.9s.

[0068] (4) Analysis of dynamic triaxial test results

[0069] Without MICP treatment (C Ca 2+ =0mol / L, D m =0), the results of the multi-stage loading cumulative plastic strain test under the conditions of σ3 = 30 kPa and different ω (0.9 OMC, OMC, 1.1 OMC) are as follows: Figure 3 As shown. Different C Ca 2+ (0mol / L, 0.5mol / L, 1mol / L and 2mol / L) solid waste samples, at ω=OMC, σ3=30kPa and D m =0,6(C Ca 2+ =0mol / L, D m =0) under the condition of multi-stage loading cumulative plastic strain test results are as follows Figure 4 As shown. Different D m Solid waste samples (0, 1, 3, 6, 10) at ω = OMC, σ3 = 30 kPa and C Ca 2+ =0, 1 mol / L(D m =0, C Ca 2+ =0mol / L) under the condition of multi-stage loading cumulative plastic strain test results are as follows Figure 5 shown.

[0070] Step d:

[0071] The present invention is based on the multi-stage loading cumulative plastic strain test results shown in the previous step ( Figures 3 to 5 ), establish comprehensive consideration C Ca 2+ 、D m , σ d The steps of establishing the multi-stage loading cumulative plastic strain prediction model for , ω, and N are shown in formulas (4) to (8), and the model parameters are shown in Table 1:

[0072] ① First, a basic prediction model for the cumulative plastic strain of multi-level loading is established, which includes comprehensive consideration of C Ca 2+ 、D m , σ d , the f function of ω and the independent term considering the number of cyclic loading N, as shown in formula (4):

[0073]

[0074] ②Basis Figures 3 to 5 The test results shown in the figure show that C Ca 2+ 、D m , σ d The influence of ω and the cumulative plastic strain of multi-level loading are studied, and the specific expression of the f function is established based on the principle of coupling of influencing factors and dimensional unification, as shown in formula (5):

[0075]

[0076] ③ In the study of soil mechanics and MICP-modified materials, matrix suction is a key factor affecting material strain and strength. To further accurately describe the variation of matrix suction under different conditions, this paper uses the VAN-GENUCHTEN model to derive it. Assuming that the porosity remains unchanged, the calculation expressions for water content and matrix suction are shown in formulas (6) to (7):

[0077]

[0078] ④Combination Figure 2 The final expression of the multi-level loading cumulative plastic strain prediction model can be obtained by combining formulas (4) to (7), as shown in formula (8):

[0079]

[0080] Where: is the accumulated plastic strain; C Ca 2+ is the calcium ion concentration; D m is the number of maintenance days; σ d is the dynamic loading stress; ω is the water content; N is the number of cyclic loading; is the standard calcium ion concentration, which is 1 mol / L; e is a mathematical constant, which is 2.718; P a is the atmospheric pressure, which is 100kPa; ω i is the actual moisture content; ω omc is the optimal moisture content; S r-i is the saturation corresponding to the actual moisture content; S r-omc is the saturation corresponding to the optimal moisture content; S r-r is the residual saturation; is matrix suction; is the matrix suction when water content = i; is the matrix suction when the water content is OMC; a, n, and m are the VAN-GENUCHTEN model parameters (the three model parameters are obtained by Figure 2 The results of the filter paper method were calculated using the VG model combined with the least squares method. ) The values ​​are a=0.23, n=24.68, m=0.01; a1, a2, b1, b2, b3, b4, b5, b6, and b7 are model parameters.

[0081] Table 1 Statistics of estimated model parameters

[0082]

[0083] In addition, in order to determine the applicability of the MICP technology proposed in this invention to improve the prediction method of the cumulative plastic strain of construction waste under multi-stage loading, the robustness of the new model of this invention - formula (8) was verified. The measured value of the cumulative plastic strain is the horizontal axis and the predicted value is the vertical axis, and then a robustness verification scatter plot is drawn. The results are as follows: Figure 6 As shown. It can be seen that most of the scattered points are concentrated around the straight line y=x, R 2 =0.96, RMSE=0.04, and the fitting effect is good. Therefore, the cumulative plastic strain obtained by the new model under multi-level loading is highly representative and meets engineering needs.

[0084] Each embodiment in this specification is described in a related manner. The same or similar parts between the embodiments can be referred to in conjunction with each other. Each embodiment focuses on the differences from other embodiments. The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are included in the scope of protection of the present invention.

Claims

1. A method for constructing a prediction model for the cumulative plastic strain of multi-stage loading of construction waste based on MICP, characterized in that: The specific steps are as follows: Step (1) selecting construction waste materials for crushing and screening, and conducting a system basic physical property test; based on the above basic physical property test, measuring the soil-water characteristic curve of the construction waste and determining the water absorption characteristics of the construction waste under different water content states; Step (2) adding equal volumes of MICP improvement reaction solutions of different concentrations to the sample and mixing thoroughly; Step (3) forming the sample prepared in step (2) into a cylindrical sample and compacting it, and then curing it under different time conditions; Step (4) Dynamic triaxial test The multi-stage loading cumulative plastic strain test method was adopted, and a total of 4 stress levels were designed for the multi-stage loading permanent deformation test. The multi-stage loading cumulative plastic strain test results under different conditions were then obtained. Step (5) Based on the results of step (1) and step (4), construct a comprehensive consideration of C Ca 2+ 、D m , σ d , ω, N multi-stage loading cumulative plastic strain prediction model; The model is: Where: C Ca 2+ is the calcium ion concentration; D m is the number of maintenance days; σ d is the dynamic loading stress; N is the number of cyclic loading; is the standard calcium ion concentration, which is 1 mol / L; e is a mathematical constant, which is 2.718; P a is the atmospheric pressure, which is 100kPa; is the matrix suction when the water content ω = i; is the matrix suction when the water content ω is OMC; a, n, m are the parameters of the VAN-GENUCHTEN model; a1, a2, b1, b2, b3, b4, b5, b6, and b7 are model parameters.

2. The method for constructing a model according to claim 1, wherein: In step (1), the VAN-GENUCHTEN model is used to determine the water absorption characteristics of construction waste under different water content states.

3. The method for constructing a model according to claim 1, wherein: In step (2), C in the reaction solution Ca 2+ The concentrations were set to 0 mol / L, 0.5 mol / L, 1 mol / L, and 2 mol / L, and the bacteria used in the reaction solution was Sporosarcina pasteurianus.

4. The method for constructing a model according to claim 1, wherein: In step (4), during the test, the confining pressure is set to 30 kPa, the dynamic loading stress is set to 15 kPa, 30 kPa, 45 kPa, and 60 kPa, respectively, the number of loading times for each level is 10,000 times, the loading frequency is 1 Hz, the loading time is 0.1 s, and the intermittent time is 0.9 s.

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