A self-regulating recycling reinforcement system and construction method based on MICP (Multi-Ingredient Polymerization) of construction solid waste

Abstract

This invention discloses a self-regulating circulating reinforcement system and construction method based on construction solid waste and synergistic MICP (Mineralized Organic Powder). The system includes a matrix construction layer, a dual-channel grouting pipe network, a grouting unit, a circulating drainage unit, a permeability monitoring unit, and a central control unit. The method includes: pre-mixing crushed and screened construction solid waste with mineralized bacterial solution for backfilling; laying a dual-channel grouting pipe network; using the central control unit to calculate the target stiffness based on a multi-level loading cumulative plastic strain prediction model, and controlling the injection flow rate and pressure of the gelling liquid; and recovering the reaction byproduct ammonium ions in real time through the circulating drainage module, and adjusting the grouting strategy based on the chemical parameters of the backfilled liquid. This application not only realizes the resource utilization of construction waste, but also solves the problems of uneven MICP reinforcement and ammonium contamination through intelligent closed-loop control, and possesses the ability to self-repair and replenish soil damage in the later stages.

Description

Technical Field

[0001] This application relates to the technical fields of geotechnical engineering foundation treatment, ecological restoration and computer-aided design, and specifically to a self-regulating cyclic reinforcement system and construction method based on construction solid waste collaborative MICP. Background Technology

[0002] With the acceleration of urbanization, a large amount of construction waste (such as waste concrete and brick rubble) is generated. Meanwhile, traditional MICP reinforcement technology faces three major challenges in practical applications: 1. Environmental pollution: During the MIP reaction, urea hydrolysis produces a large amount of ammonium ions (NH4+). + Direct discharge of such substances would cause eutrophication and pollution of groundwater.

[0003] 2. Poor uniformity of reinforcement: Although segmented grouting has solved some problems with existing technologies, in complex-graded construction solid waste accumulations, the grout is very easy to lose along the dominant channels, resulting in reinforcement dead zones.

[0004] 3. Lack of long-term performance prediction and control: Although existing technologies have established a cumulative plastic strain prediction model, this model is currently mainly used for theoretical analysis and has not yet formed a closed loop with the real-time control system during the construction process. It is impossible to predict the reinforcement effect and adjust the process in real time during the construction stage.

[0005] Therefore, there is an urgent need for an intelligent MICP reinforcement system that can efficiently utilize construction solid waste, solve ammonium pollution, and apply theoretical prediction models to real-time construction control. Summary of the Invention

[0006] To address the shortcomings of existing microbial induced calcium carbonate precipitation (MICP) technology in practical engineering applications, such as groundwater pollution by reaction byproducts (high concentration of ammonium ions), easy clogging during grouting and poor reinforcement uniformity, and lack of theoretical basis for determining construction termination, relying on experience and blind operation, this application provides a self-regulating cyclic reinforcement system and construction method based on construction solid waste synergistic MICP.

[0007] The technical solution provided in this application is as follows.

[0008] In a first aspect, this application provides a grouting control method, comprising: Acquire real-time sensor parameters and soil parameters; the sensor parameters include changes in pore water pressure. resistivity change rate pH value and calcium ion concentration of the backflow solution 2+ The soil parameters include dynamic stress amplitude. Cumulative loading times N, initial elastic modulus of soil and matrix suction S; Based on the piecewise hyperbolic correction algorithm, the cumulative plastic strain of the current solid waste aggregate layer is calculated. The calculation results were obtained by taking its rate of change and the predicted value of unconfined compressive strength (UCS). Based on the monitoring and calculation results of sensor parameters and soil parameters, grouting parameters are adjusted through bidirectional control of feedforward and feedback.

[0009] In one possible implementation, the Nth cumulative plastic strain The calculation formula is as follows:

[0010] in: This is the initial elastic modulus of the soil. These are the hyperbolic nonlinear coefficients; This represents the equivalent stress increment during the i-th grouting cycle. ， Let be the grouting pressure for the i-th injection. Let N represent the change in pore water pressure during the i-th grouting, N represent the cumulative number of loadings, and t represent the cumulative grouting time. The MICP mineralization coupling function is given by the following formula:

[0011] in, , , , These are empirical constants obtained through indoor testing.

[0012] Furthermore, the accumulated plastic strain The rate of change is the cumulative plastic strain The derivative of the cumulative grouting time t.

[0013] Furthermore, the formula for calculating the predicted value of the unconfined compressive strength (UCS) is as follows:

[0014] in , , These are the regression parameters.

[0015] In one possible implementation, the monitoring and calculation results based on sensor parameters and soil parameters are used to adjust the grouting parameters through bidirectional feedforward and feedback control, including: Adjust the injection volume and concentration of the bacterial solution for the next round based on the pH value and calcium ion concentration consumption rate of the back-extracted solution. according to The rate of change is used to adjust the grouting pressure p and the settling time; based on... Based on the rate of change and UCS prediction values, determine whether to stop grouting; Based on real-time monitoring of resistivity, pH, and Ca 2+ Concentration deviation value, dynamic correction of grouting flow rate v and settling time ; Based on the changes in local resistivity, determine whether to activate the high-pressure pulse cleaning program.

[0016] Furthermore, the aforementioned according to The rate of change, adjusting the grouting pressure p and the settling time, includes: like When the grouting rate is >0.05% / h, reduce the grouting pressure and extend the settling time; when If the grouting pressure is less than 0.05% / h and the predicted UCS value is less than the preset value, increase the grouting pressure and reduce the settling time. when If the grouting rate is less than 0.05% / h and the predicted UCS strength is greater than or equal to the design value, then grouting should be stopped.

[0017] Furthermore, the method based on real-time monitoring of resistivity, pH, and Ca... 2+ Concentration deviation value, dynamic correction of grouting flow rate v and settling time ,include: When the calcium ion concentration consumption rate is <20%, it indicates that the mineralization reaction is insufficient. If the local resistivity is lower than the preset lower limit, the grouting flow rate is increased from 5.0 L / min to 6.0 L / min, and the settling time is extended from 60 min to 90 min. If the local resistivity is within the preset range, the grouting flow rate is maintained at 5.0 L / min, and the settling time is extended to 90 min. When the calcium ion concentration consumption rate is 20%–40%, it indicates that the mineralization reaction is in a stable and progressive stage. If the pH of the backflow solution is ≤7.5, maintain the grouting flow rate at 5.0 L / min and extend the settling time to 75 min. If the pH of the backflow solution is 7.5 < pH ≤ 8.5, maintain the grouting flow rate at 5.0 L / min and the settling time at 60 min. If the pH of the backflow solution is >8.5, maintain the grouting flow rate at 5.0 L / min and the settling time at 60 min. When the calcium ion concentration consumption rate is >40%, it indicates that the mineralization reaction is relatively sufficient. If the pH of the backflow solution is >8.5, the grouting flow rate should be reduced from 5.0 L / min to 4.0 L / min, and the settling time should be shortened from 60 min to 45 min. If the pH of the backflow solution is ≤8.5, the grouting flow rate should be kept at 5.0 L / min and the settling time at 60 min.

[0018] Secondly, this application provides a grouting control device, comprising: The acquisition module is used to acquire real-time sensor parameters and soil parameters; the sensor parameters include changes in pore water pressure. resistivity change rate pH value and calcium ion concentration (Ca) 2+ The soil parameters include dynamic stress amplitude. Cumulative loading times N, initial elastic modulus of soil and matrix suction S; The calculation module is used to calculate the cumulative plastic strain of the current solid waste aggregate layer based on the piecewise hyperbolic correction algorithm. Its rate of change and the predicted value of unconfined compressive strength (UCS); The adjustment module is used to adjust the grouting parameters based on the monitoring and calculation results of sensor parameters and soil parameters, through bidirectional control of feedforward and feedback.

[0019] Thirdly, this application provides a self-regulating cyclic reinforcement system based on co-organized MICP of construction solid waste, comprising: The matrix construction layer is composed of recycled construction waste aggregate and in-situ soil mixed according to a specific gradation. The dual-channel grouting pipe network is pre-embedded in the matrix construction layer and consists of multiple arrayed grouting units. Each grouting unit includes an inner injection pipe and an outer suction pipe. The inner injection pipe is provided with an outlet hole for injecting bacteria and cementing fluid. The outer suction pipe is provided with a permeable hole and is covered with a permeable geotextile filter layer. The circulating pumping unit includes a vacuum pump, a magnesium ammonium phosphate reaction vessel, and a circulating pump; the vacuum pump is connected to an external suction pipe. The permeation monitoring unit, located on the outer periphery of the external suction pipe, includes a micro pore water pressure gauge, a resistivity sensor, and a pH sensor. The central control unit, connected to the circulating pumping processing unit and the permeation monitoring unit, includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the functions of the grouting control device as described in the second aspect.

[0020] Fourthly, this application provides a method for construction using the self-regulating cyclic reinforcement system of the third aspect, comprising: Solid waste aggregate pretreatment and laying; A water injection test was conducted using the dual-channel intelligent grouting pipeline network to determine the initial permeability coefficient. Combined with ground-penetrating radar data, the high-permeability zone and low-permeability zone were divided using the central control unit. The gelling agent is injected into the soil through the internal injection tube, using a pulse mode of grouting-settling-suction. After the settling reaction period, the circulation and drainage treatment module is activated to extract the reaction byproducts and unreacted waste liquid through the external suction tube. The grouting parameters are adjusted through bidirectional control of feedforward and feedback from the central control unit, as well as the grouting can be started and stopped.

[0021] The beneficial effects of this application are as follows: 1. The method provided in this application realizes a fully closed-loop control process of "monitoring-prediction-adjustment-verification", which can achieve self-adjusting construction without human intervention. This control logic organically combines the MICP reaction kinetic model, soil constitutive behavior and automated control system, which significantly improves the uniformity of reinforcement, environmental safety and intelligence level.

[0022] 2. Improved environmental friendliness: The circulating pumping module extracts the ammonium ions generated by the reaction in a timely manner and treats them as bird droppings on the ground to be converted into fertilizer, thus solving the ammonia nitrogen pollution problem of MICP.

[0023] 3. Intelligent construction: Grouting is controlled by an intelligent grouting control module, no longer relying solely on experience or fixed grouting volume, but controlling grouting parameters in reverse according to the target mechanical properties, truly realizing reinforcement on demand.

[0024] 4. Resource utilization: Construction solid waste is effectively utilized, and the improved grouting process overcomes the problem of grout loss caused by the high porosity and uneven gradation of solid waste. Attached Figure Description

[0025] Figure 1 A schematic flowchart of the grouting control method provided in the embodiments of this application; Figure 2 This is a schematic diagram of the grouting control device provided in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the self-regulating cyclic reinforcement system based on collaborative MICP of construction solid waste provided in the embodiments of this application; Figure 4 This is a schematic diagram of a pulsed grouting cycle provided in an embodiment of this application; Figure 5 This is a schematic diagram of the aggregate proportioning for the matrix structure layer provided in an embodiment of this application; Figure 6 The flowchart of the feedback control of the central control unit provided in the embodiment of this application is shown. Detailed Implementation

[0026] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0027] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0028] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this technology based on the specific circumstances.

[0029] In the description of this application, spatial relation terms such as "below," "under," "below," "below," "above," "over," etc., are used herein to describe the relationship between one element or feature shown in the figures and other elements or features. It should be understood that, in addition to the orientation shown in the figures, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figures is flipped, an element or feature described as "below" or "under" or "below" of other elements or features will be oriented "above" other elements or features. Therefore, the exemplary terms "below" and "under" can include both upper and lower orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein are interpreted accordingly.

[0030] In the description of this application, the term "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use this application. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that this application can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid unnecessarily obscuring the description of this application. Therefore, this application is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0031] Existing microbial induced calcium carbonate precipitation (MICP) technology has several drawbacks in practical engineering applications, including groundwater pollution from reaction byproducts (high concentration of ammonium ions), easy blockage during grouting and poor uniformity of reinforcement, and a lack of theoretical basis for determining construction termination, relying on experience and blind operation.

[0032] In view of this, this application provides a self-regulating cyclic reinforcement system and construction method based on construction solid waste collaborative MICP.

[0033] First, we introduce a grouting control method, see [link to relevant documentation] Figure 1 ,include: S101. Acquire real-time sensor parameters and soil parameters; the sensor parameters include changes in pore water pressure. resistivity change rate The pH value and calcium ion concentration of the backflow solution 2+ The soil parameters include dynamic stress amplitude. , cumulative loading times N (cumulative effect of the model i = 1,2,3,...,N), initial elastic modulus of the soil And matrix suction S.

[0034] It should be noted that, in the embodiments of this application, the pH value and calcium ion concentration consumption rate involved in the control judgment both refer to the monitoring values ​​of the back-extraction liquid; wherein, the pH value of the back-extraction liquid is measured by the online pH detection unit at the outlet of the circulation pumping and drainage processing module, and the calcium ion concentration consumption rate is obtained by comparing the calcium ion concentration of the back-extraction liquid with the calcium ion concentration of the initial gelling liquid.

[0035] In one possible implementation, the sensor parameters include changes in pore water pressure. The resistivity change rate, pH value of the backflow solution, and calcium ion concentration consumption rate of the backflow solution are direct monitoring parameters.

[0036] In one possible implementation, the dynamic stress amplitude is one of the soil parameters. The matrix suction S is an auxiliary input parameter set or obtained through inversion based on the load conditions and soil state. Pore water pressure change refers to the change in pore fluid pressure relative to the initial state. Resistivity change rate refers to the change in pore fluid resistivity relative to the initial resistivity. In the 24-hour short-term verification example, the dynamic stress amplitude... The pressure is taken as 20 kPa, and the matrix suction S is taken as 35 kPa. The cumulative loading number N is the cumulative number of grouting loadings. Matrix suction refers to the matrix suction of the soil. The initial elastic modulus of the soil... The stress-strain curves were determined through unconfined compressive strength testing. Specifically, cylindrical specimens were prepared using the same aggregate gradation, compaction conditions, and curing conditions as in the examples. Uniaxial compression loading was performed using an unconfined compressive strength testing machine, and the stress-strain curves of the specimens were recorded. The slope of the initial linear segment was taken as the initial elastic modulus of the soil. .

[0037] S102. Calculate the cumulative plastic strain of the current solid waste aggregate layer based on the piecewise hyperbolic correction algorithm. The calculation results were obtained by taking into account the rate of change of the unconfined compressive strength (UCS) and the predicted value of the unconfined compressive strength.

[0038] In one possible implementation, the Nth cumulative plastic strain The calculation formula is as follows:

[0039] in: This is the initial elastic modulus of the soil. These are the hyperbolic nonlinear coefficients; This represents the equivalent stress increment during the i-th grouting cycle. ， The grouting pressure is the pressure of the i-th grouting operation. For the change in pore water pressure during the i-th grouting, , The pore water pressure during the i-th grouting is... Indicates the initial pore water pressure (before grouting); N represents the cumulative number of loading cycles, and t represents the cumulative grouting time; The MICP mineralization coupling function is given by the following formula:

[0040] in, , , , These are empirical constants obtained through indoor testing.

[0041] Furthermore, the hyperbolic nonlinear coefficient The calibration was obtained through indoor cyclic loading tests, including methods such as: different equivalent stress increments. Measure the corresponding cumulative plastic strain The parameters are obtained by using a hyperbolic model for nonlinear regression fitting. .

[0042] Furthermore, the aforementioned , , , For the empirical parameters of the coupling function, the calibration methods include: based on the measured results of pH value and calcium ion concentration consumption rate, pore water pressure change and unconfined compressive strength of the backflow solution under the curing conditions, and combined with the model change trend, a demonstrative calibration is carried out.

[0043] For example, in this embodiment, the experimental results of pH value and calcium ion concentration consumption rate of the backflow solution, pore water pressure change and unconfined compressive strength under 24-hour short-term maintenance conditions are used to perform exemplary calibration in combination with the model change trend.

[0044] In this embodiment, k1 is 0.85 and k2 is 0.06h. -1 K3 is taken as 0.4 L / mol, and K4 is taken as 0.12. Under different curing times, different aggregate gradations, or different working conditions, the above parameters can be further corrected and determined through corresponding indoor tests.

[0045] In one possible implementation, the accumulated plastic strain The rate of change is the cumulative plastic strain The derivative of the cumulative grouting time t.

[0046] In one possible implementation, the formula for calculating the predicted unconfined compressive strength (UCS) is as follows:

[0047] in , , These are the regression parameters.

[0048] S103. Based on the monitoring and calculation results of sensor parameters and soil parameters, the grouting parameters are adjusted through bidirectional control of feedforward and feedback.

[0049] In one possible implementation, S103 includes: S103a. Adjust the injection volume and concentration of the bacterial solution for the next round based on the pH value and calcium ion consumption rate of the back-extracted solution. ; S103b, according to The rate of change is used to adjust the grouting pressure p and the settling time; based on... Based on the rate of change and UCS prediction values, determine whether to stop grouting; S103c, based on real-time monitoring of resistivity, pH value, and Ca 2+ Concentration deviation value, dynamic correction of grouting flow rate v and settling time ; S103d. Based on the changes in local resistivity, determine whether to start the high-pressure pulse cleaning program.

[0050] Furthermore, in S103a, the adjustment of the next round of bacterial culture injection: When the pH of the backflow solution is ≤7.5, increase the amount of bacterial solution injected in the next round; When 7.5 < pH of the backflow solution ≤ 8.5 and the calcium ion concentration consumption rate is 20% to 40%, maintain the current bacterial culture injection volume; When the pH of the backflow solution is greater than 8.5 and the calcium ion concentration consumption rate is greater than 40%, reduce the amount of bacterial solution injected in the next round. For crossover scenarios that do not fall within the above ranges, including cases where the pH of the backfill solution is ≤7.5 and the calcium ion concentration consumption rate is >40%, and cases where the pH of the backfill solution is >8.5 and the calcium ion concentration consumption rate is 20% to 40%, the current bacterial culture injection volume should be maintained unchanged, or a fine adjustment should be made based on the changing trends of two consecutive monitoring cycles.

[0051] Furthermore, in S103a, the bacterial concentration is adjusted as follows: When the calcium ion concentration consumption rate is <20%, the bacterial concentration should be increased to OD. 600 =1.20; When the calcium ion consumption rate is 20%–40% and the pH of the backflow solution is ≤7.5, the bacterial concentration should be increased to OD. 600 =1.20; When the calcium ion consumption rate is 20%–40% and the pH of the backflow solution is 7.5 < pH ≤ 8.5, the bacterial concentration should be maintained at OD. 600 =1.10; When the calcium ion consumption rate is 20%–40% and the pH of the backflow solution is >8.5, the bacterial concentration should be maintained at OD. 600 =1.10; When the calcium ion consumption rate is >40% and the pH of the backflow solution is >8.5, reduce the bacterial concentration to OD. 600 =1.00; When the calcium ion consumption rate is >40% and the pH of the backflow solution is ≤8.5, maintain the bacterial concentration at OD. 600 =1.10.

[0052] Furthermore, in S103b, the grouting pressure is adjusted as follows: like When the grouting rate is >0.05% / h, reduce the grouting pressure and extend the settling time; when If the grouting pressure is less than 0.05% / h and the UCS predicted value is less than the preset strength threshold, increase the grouting pressure and reduce the settling time. when If the grouting rate is less than 0.05% / h and the UCS predicted intensity is greater than or equal to the preset intensity threshold, then grouting should be stopped.

[0053] Furthermore, in S103c, when the calcium ion concentration consumption rate is <20%, it indicates that the mineralization reaction is insufficient. At this time, if the local resistivity is lower than the preset lower limit, it indicates that the grout diffusion is fast and the cementation is not sufficient. In this case, the grouting flow rate is increased from 5.0 L / min to 6.0 L / min, and the standing time is extended from 60 min to 90 min. If the local resistivity is within the preset range, the grouting flow rate is maintained at 5.0 L / min, and the standing time is extended to 90 min. When the calcium ion concentration consumption rate is 20%–40%, it indicates that the mineralization reaction is in a stable and progressive stage. If the pH of the backflow solution is ≤7.5, maintain the grouting flow rate at 5.0 L / min and extend the settling time to 75 min. If the pH of the backflow solution is 7.5 < pH ≤ 8.5, maintain the grouting flow rate at 5.0 L / min and the settling time at 60 min. If the pH of the backflow solution is >8.5, maintain the grouting flow rate at 5.0 L / min and the settling time at 60 min. When the calcium ion concentration consumption rate is >40%, it indicates that the mineralization reaction is relatively sufficient. If the pH of the backflow solution is >8.5, the grouting flow rate should be reduced from 5.0 L / min to 4.0 L / min, and the settling time should be shortened from 60 min to 45 min. If the pH of the backflow solution is ≤8.5, the grouting flow rate should be kept at 5.0 L / min and the settling time at 60 min.

[0054] Furthermore, in S103d, when the resistivity of a local area increases by 25% or more within two adjacent monitoring cycles, it is determined that the area has a blockage trend, and a high-pressure pulse cleaning program is initiated. The cleaning pressure of the high-pressure pulse cleaning program is 120 kPa, each cleaning lasts for 15 seconds, and is executed three times consecutively. After cleaning, the resistivity of the area is re-detected. When the resistivity returns to the preset range, normal grouting is resumed; when the resistivity is still higher than the preset upper limit, another round of high-pressure pulse cleaning is executed or the grouting operation in the area is suspended.

[0055] The grouting control method will be described below with reference to more detailed embodiments.

[0056] I. Material Selection and Preparation The aggregate used in construction solid waste was selected with coarse aggregate of 5-20 mm and fine aggregate of 2-5 mm, in a 7:3 mass ratio. Two cylindrical specimens (Φ50 mm × 100 mm) were prepared (Specimen A for measured UCS value, and specimen B for predicted value). Bacillus pasteurization solution was used, with OD... 600 =1.2; slowly inject it into the sample and let it stand for a period of time. Prepare a 1 mol / L urea-CaCl2 gelling solution and slowly inject it into the sample at the same time, and cure at room temperature for 24 hours.

[0057] II. Sample Test Indicators: The measured unconfined compressive strength UCS of specimen A is shown in Figure 1.

[0058] Initial Ca of the cementitious solution measured in sample B 2+ Concentration C0, Ca after 24 hours of curing 2+ Concentration C1, pH value, grouting pressure p g pore water pressure change value And according to the parameters specified in the demonstration calibration (dynamic stress amplitude σ) d The matrix suction (S) is used to calculate the final unconfined predicted compressive strength UCS (2).

[0059] III. Sample test data and calculation results are shown in Table 1: Table 1. Sample test data and calculation results

[0060] In Table 1, the calculated data were obtained using the methods described above.

[0061] In this embodiment, the initial elastic modulus of the soil Take 20 MPa. This value is determined based on the slope of the initial linear segment of the stress-strain curve of the cylindrical specimen under the same mix ratio, compaction conditions and curing conditions as in the example.

[0062] 3.1 Explanation of the values ​​of relevant parameters in Table 1: After 24 hours of curing, the MIP bond is still in its early formation stage. Applying excessively high dynamic stress could damage the incompletely formed bond bridges. Furthermore, since the sample is a small cylindrical specimen used for static UCS verification, the dynamic stress amplitude σ was set to... d The value for "mild environmental disturbance" is 20 kPa. In the embodiments of this application, the sample containing a porous system of solid waste aggregate is subjected to a medium suction level of 35 kPa (matrix suction S).

[0063] 3.2 Values ​​of empirical parameters k1-k4: (1) k1 is the overall amplitude coefficient. Considering that 24 hours is the early curing stage and the MIP bonding has not been fully utilized, a conservative value of 0.85, which is slightly lower than 1, is taken.

[0064] (2) k2 is the time growth rate constant, controlling the time term ( To determine the rate of increase of the time effect term (k2) under 24-hour conditions, and to reflect that mineralization has occurred significantly but has not yet reached a stable level during the short-term maintenance phase, k2 is set to 0.06 hours in this embodiment. -1 .

[0065] (3) k3 is Ca 2+ Sensitivity coefficient, Ca in this experiment 2+ The consumption rate is 0.32 mol / L. Considering the objective losses, a rate of 0.4 L / mol is more reasonable.

[0066] (4) The stress-suction attenuation sensitivity coefficient k4 is 0.12 to ensure that under low amplitude dynamic stress and medium matrix suction, the attenuation term can reflect the adverse effects of stress disturbance on the early cemented structure, but will not cause the predicted strength of the 24-hour verification sample to be excessively weakened.

[0067] 3.3 Values ​​of regression parameters a0, a1, and b1: The strength regression parameters a0, a1, and b1 are selected based on the foundation strength level of the building solid waste compaction, the target value of the 28-day design UCS in the embodiment of this application, and the reasonable strength range of the 24-hour short-term curing specimen. Among them, a0=0.45MPa represents the foundation bearing capacity when it is not fully bonded, a1=2.20MPa is used to control the upper limit of the theoretical strength after mineralization gain, and b1=1.80 is used to match the sensitivity between the cumulative plastic strain and UCS under 24-hour conditions.

[0068] The relative error between the predicted and measured values ​​is 3.8%, indicating that the method provided in this application embodiment can well reflect the strength development trend of the solid waste synergistically reinforced with MIP under 24-hour short-term curing conditions, with small prediction error, and has practicality and application value.

[0069] Next, we will introduce the device based on the aforementioned grouting control method.

[0070] See Figure 2 A grouting control device, comprising: Acquisition module 21 is used to acquire real-time sensor parameters and soil parameters; the sensor parameters include changes in pore water pressure. resistivity change rate pH value and calcium ion concentration (Ca) 2+ The soil parameters include dynamic stress amplitude. Cumulative loading times N, initial elastic modulus of soil and matrix suction S; Calculation module 22 is used to calculate the cumulative plastic strain of the current solid waste aggregate layer based on the piecewise hyperbolic correction algorithm. Its rate of change and the predicted value of unconfined compressive strength (UCS); The adjustment module 23 is used to adjust the grouting parameters through bidirectional control of feedforward and feedback based on the monitoring and calculation results of sensor parameters and soil parameters.

[0071] Then, we introduce a self-regulating cyclic reinforcement system based on the aforementioned device and the collaborative MICP of construction solid waste.

[0072] See Figure 3 A self-regulating cyclic reinforcement system based on collaborative MICP of construction solid waste includes: The matrix construction layer is composed of recycled construction waste aggregate and in-situ soil mixed according to a specific gradation. The dual-channel grouting network consists of multiple arrayed grouting units; each grouting unit includes an inner injection pipe and an outer suction pipe; the inner injection pipe is provided with an outlet hole for injecting bacteria and cementing fluid; the outer suction pipe is provided with a permeable hole and is covered with a permeable geotextile filter layer. The circulating pumping unit includes a vacuum pump, a magnesium ammonium phosphate reaction vessel, and a circulating pump; the vacuum pump is connected to an external suction pipe. The permeation monitoring unit, located on the outer periphery of the external suction pipe, includes a micro pore water pressure gauge, a resistivity sensor, and a pH sensor. The conditioning tank is connected to the magnesium ammonium phosphate reaction vessel and the inner injection tube via a vacuum pump; The central control unit, connected to the circulating pumping processing unit and the permeation monitoring unit, includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the functions of the grouting control device as described above.

[0073] Figure 3 The diagram illustrates the circulation path between the matrix construction layer and the circulating extraction and treatment module. Bacterial solution and gelling liquid are input through the inner injection tube and enter the pores of the matrix construction layer through the outlet holes on the side wall of the inner injection tube, forming an inward-to-outward permeation diffusion path between the inner injection tube and the outer suction tube. The reacted pore liquid, under the negative pressure of the outer suction tube, enters through the circumferential permeation holes of the outer suction tube and is transported to the vacuum pump. The extracted liquid enters the magnesium ammonium phosphate reaction tank, where magnesium salt and phosphate are added, causing the ammonium ions in the returned liquid to precipitate as magnesium ammonium phosphate. The treated supernatant is returned to the gelling liquid preparation tank or regulating tank via a circulation pump. A valve assembly is used to switch between the return branch and the discharge branch, thus forming a circulation path of "inner tube injection—pore diffusion—outer tube recovery—reaction treatment—liquid return."

[0074] The function of the permeable geotextile filter layer set around the outer periphery of the external suction pipe is: 1. Allow soil pore fluid and waste liquid after reaction to enter the external suction pipe under negative pressure to achieve pumping and recycling; 2. Prevents fine particles of construction solid waste, microbial aggregates, and calcium carbonate precipitates from directly entering the suction pipe, reducing the risk of blockage; 3. The negative pressure suction effect is more evenly distributed along the circumference of the outer suction pipe, forming a directional seepage path from the inner injection pipe to the outer suction pipe, thereby improving the uniformity of grout coverage in the reinforced area. 4. During the extraction and drainage stage, the pore liquid containing ammonium byproducts is promptly discharged to facilitate subsequent resource recovery and treatment in the circulating extraction and drainage module, thereby reducing the risk of ammonia nitrogen pollution.

[0075] The magnesium ammonium phosphate reaction tank is used to react the extracted pore liquid rich in ammonium ions with magnesium salts and phosphates to generate slow-release fertilizer. The supernatant after treatment is returned to the gelling liquid preparation tank.

[0076] Figure 4 The diagram illustrates three stages of a pulsed grouting cycle: a grouting stage, a settling stage, and a drainage stage. In the grouting stage, bacterial solution and / or gelling agent are injected into the matrix building layer through an internal injection tube, preferably for 30 minutes. In the settling stage, grouting is stopped, allowing the mineralization reaction to occur within the aggregate-soil pores, preferably for 60 minutes. In the drainage stage, the reacted pore fluid and byproducts are recovered through an external suction pipe to reduce ammonium contamination and prepare for the next cycle.

[0077] Figure 5 A schematic diagram of the aggregate proportioning for the matrix structure layer is shown.

[0078] Figure 6 The feedback control flowchart of the central control unit is shown.

[0079] Finally, the construction method using the aforementioned self-regulating circulation reinforcement system is introduced, including: S1. Pretreatment and laying of solid waste aggregate; S2. A water injection test is conducted through the dual-channel intelligent grouting pipeline network to determine the initial permeability coefficient. Combined with ground-penetrating radar data, the high-permeability zone and low-permeability zone are divided using the central control unit. S3. Inject gelling liquid into the soil through the inner injection tube, using a pulse mode of grouting-static-suction; after the static reaction period, start the circulation and drainage treatment module to extract the reaction byproducts and unreacted waste liquid through the outer suction tube. S4. Grouting parameters are adjusted through bidirectional control of feedforward and feedback from the central control unit, as well as grouting is started and stopped.

[0080] Specifically, the construction methods include: Step 1: Solid waste aggregate pretreatment and matrix construction Waste concrete blocks are collected and crushed using a jaw crusher. Coarse aggregate (5-20mm) and fine aggregate (2-5mm) are screened out. The coarse and fine aggregates are mixed at a mass ratio of 7:3, washed with clean water to remove surface dust, dried, and then backfilled into the soft soil area to be reinforced to form an aggregate skeleton. The backfill compaction degree is controlled between 0.90 and 0.93.

[0081] Step 2: Deployment of Intelligent Pipeline Network A coaxial annular dual-channel grouting unit is adopted, which consists of an inner injection tube located at the center and outer suction tubes arranged around the periphery of the inner injection tube. The whole unit forms a staggered array on the plane, with the tubes arranged at a spacing of 1.5m. The inner injection tube has a diameter of 25mm and is made of PVC; the outer suction tube has a diameter of 60mm, a tube wall porosity of 15%, and its outer periphery is covered with a permeable geotextile filter layer.

[0082] Monitoring points were set at depths of 1m, 3m, and 5m around a representative grouting unit and at a predetermined distance from the outer wall of the external suction pipe. Each monitoring point was equipped with a pore water pressure sensor, a resistivity sensor, and a pH sensor to monitor the pore fluid state at different depths.

[0083] The central control unit is used to perform median filtering and weighted averaging on pH and resistivity data from multiple monitoring points at the same depth to obtain representative parameters for that depth.

[0084] The pore water pressure data is processed by depth layer using a central control unit. Specifically, the pore water pressure sensor data located at different depths of the matrix construction layer are assigned to the corresponding depth layer. Within each depth layer, when there are multiple monitoring points, the maximum pore water pressure value among all monitoring points in that layer is taken first as the control pore water pressure for that layer, and the degree of grouting disturbance in that layer is determined by combining the gradient of the change of this maximum value in adjacent monitoring cycles.

[0085] The pore water pressure change in the formula This is the difference between the control pore water pressure value of the control layer in the current monitoring cycle and the initial pore water pressure value of the control layer (before grouting). When a certain depth layer... When the preset upper limit is exceeded, the central control unit reduces the grouting pressure in the corresponding area or suspends grouting; when a certain depth layer When the gradient change abnormally increases, it is determined that there is a local seepage anomaly or blockage trend in the area, triggering local cleaning or flow restriction control. In a preferred embodiment, the control layer is selected as the depth layer with the largest change in pore water pressure among all depth layers, to ensure the equivalent stress increment in the model calculation. It can reflect the most unfavorable working conditions.

[0086] When any abnormal change occurs at any monitoring point, the central control unit will prioritize triggering local cleaning, flow restriction, or suspension of grouting operations in the corresponding area based on the abnormal point data.

[0087] Step 3: Inoculation and Adsorption of Bacterial Solution Bacillus pasteurellii was selected as the mineralization strain. It was cultured to the logarithmic growth phase, resulting in an OD concentration of [missing information - likely a specific concentration]. 600 The concentration should reach 1.0-1.2, and the urease activity should not be less than 10 mM urea / min (each gram of sample can hydrolyze 10 mg of urea at 30℃). Inject the bacterial solution through the inner injection tube at a flow rate of 5 L / min, with the injection volume being 1.1 times the pore volume. After injection, allow it to stand for 4-6 hours to allow the bacteria to fully adsorb into the micropores of the solid waste aggregate.

[0088] Step 4: Pulse-type circulating grouting S1. Preparation of gelling solution: Mix urea and calcium chloride in a 1:1 molar ratio to prepare a gelling solution with a concentration of 1.0 mol / L.

[0089] S2, Pulse Grouting: Activate the central control unit and set the pulse mode to "grouting for 30 minutes, then resting for 60 minutes". Control the grouting pressure within the low-pressure range of 50-80 kPa to prevent hydraulic fracturing.

[0090] S3. Negative Pressure Suction: Simultaneously with the start of grouting, the vacuum pump connected to the external pipe is activated to maintain a negative pressure of -20 kPa. A seepage and diffusion path is formed from the inside to the outside between the inner injection pipe and the outer suction pipe. The liquid diffuses through the aggregate pores to cover the entire aggregate area, and the waste liquid after reaction is promptly extracted.

[0091] Step 5: Wastewater Treatment and Resource Utilization After being drawn out through an external suction pipe, the backflow solution enters the magnesium ammonium phosphate reactor through a pipeline under the action of a vacuum pump. Subsequently, magnesium chloride and disodium hydrogen phosphate are added to the magnesium ammonium phosphate reactor to achieve a Mg:N:P molar ratio of 1.2:1:1, and the pH of the reaction system is adjusted to 9.0. After stirring for 30 minutes, the mixture is allowed to settle, and the struvite (magnesium ammonium phosphate) at the bottom of the reactor is recovered as green fertilizer. Once the ammonia nitrogen concentration in the supernatant is found to be below 15 mg / L, it is discharged into an equalization tank to replenish calcium for recycling.

[0092] Step Six: Termination Determination of Central Control Unit The central control unit collects sensor data once every grouting cycle, inputs relevant parameter data, and outputs calculation results. The system automatically issues a stop command when the following two conditions are met simultaneously: (1) the predicted 28-day unconfined compressive strength UCS reaches the design requirement value of 2.5MPa; (2) the cumulative plastic strain rate is less than the set threshold of 0.05% / h for three consecutive cycles.

[0093] This process requires no human intervention, achieving automated closed-loop control of the construction.

[0094] The above description is merely a preferred embodiment of this application, but the scope of protection of this application is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A grouting control method, characterized in that, include: Acquire real-time sensor parameters and soil parameters; the sensor parameters include changes in pore water pressure. resistivity change rate pH value and calcium ion concentration of the backflow solution 2+ ; The soil parameters include dynamic stress amplitude. Cumulative loading times N, initial elastic modulus of soil and matrix suction S; Based on the piecewise hyperbolic correction algorithm, the cumulative plastic strain of the current solid waste aggregate layer is calculated. The calculation results were obtained by taking its rate of change and the predicted value of unconfined compressive strength (UCS). Based on the monitoring and calculation results of sensor parameters and soil parameters, grouting parameters are adjusted through bidirectional control of feedforward and feedback.

2. The method according to claim 1, characterized in that, Nth cycle cumulative plastic strain The formula for calculating the Nth cycle cumulative plastic strain is as follows: in: This is the initial elastic modulus of the soil. These are the hyperbolic nonlinear coefficients; This represents the equivalent stress increment during the i-th grouting cycle. ， Let be the grouting pressure for the i-th injection. Let N represent the change in pore water pressure during the i-th grouting, N represent the cumulative number of loadings, and t represent the cumulative grouting time. The MICP mineralization coupling function is as follows: wherein , , , is an empirical constant obtained by calibration of indoor tests.

3. The method according to claim 2, characterized in that, The cumulative plastic strain The rate of change is the cumulative plastic strain The derivative of the cumulative grouting time t.

4. The method according to claim 2, characterized in that, The formula for calculating the predicted value of the unconfined compressive strength (UCS) is as follows: in , , These are the regression parameters.

5. The method according to claim 1, characterized in that, The monitoring and calculation results based on sensor parameters and soil parameters are used to adjust grouting parameters through bidirectional feedforward and feedback control, including: Adjust the injection volume and concentration of the bacterial solution for the next round based on the pH value and calcium ion concentration consumption rate of the back-extracted solution. according to The rate of change is used to adjust the grouting pressure p and the settling time; based on... Based on the rate of change and UCS prediction values, determine whether to stop grouting; Based on real-time monitoring of resistivity, pH, and Ca 2+ Concentration deviation value, dynamic correction of grouting flow rate v and settling time ; Based on the changes in local resistivity, determine whether to activate the high-pressure pulse cleaning program.

6. The method according to claim 5, characterized in that, According to The rate of change, adjusting the grouting pressure p and the settling time, includes: like When the grouting rate is > 0.05% / h, reduce the grouting pressure and extend the settling time; when If the grouting pressure is less than 0.05% / h and the predicted UCS value is less than the preset value, increase the grouting pressure and reduce the settling time. when If the grouting rate is less than 0.05% / h and the predicted UCS strength is greater than or equal to the design value, then grouting should be stopped.

7. The method according to claim 5, characterized in that, The method is based on real-time monitoring of resistivity, pH, and Ca. 2+ Concentration deviation value, dynamic correction of grouting flow rate v and settling time ,include: When the calcium ion concentration consumption rate is <20%, it indicates that the mineralization reaction is insufficient. If the local resistivity is lower than the preset lower limit, the grouting flow rate is increased from 5.0 L / min to 6.0 L / min, and the settling time is extended from 60 min to 90 min. If the local resistivity is within the preset range, the grouting flow rate is maintained at 5.0 L / min, and the settling time is extended to 90 min. When the calcium ion concentration consumption rate is 20%–40%, it indicates that the mineralization reaction is in a stable and progressive stage. If the pH of the backflow solution is ≤7.5, maintain the grouting flow rate at 5.0 L / min and extend the settling time to 75 min. If the pH of the backflow solution is 7.5 < pH ≤ 8.5, maintain the grouting flow rate at 5.0 L / min and the settling time at 60 min. If the pH of the backflow solution is >8.5, maintain the grouting flow rate at 5.0 L / min and the settling time at 60 min. When the calcium ion concentration consumption rate is >40%, it indicates that the mineralization reaction is relatively sufficient. If the pH of the backflow solution is >8.5, the grouting flow rate should be reduced from 5.0 L / min to 4.0 L / min, and the settling time should be shortened from 60 min to 45 min. If the pH of the backflow solution is ≤8.5, the grouting flow rate should be kept at 5.0 L / min and the settling time at 60 min.

8. A grouting control device, characterized in that, include: The acquisition module is used to acquire real-time sensor parameters and soil parameters; the sensor parameters include changes in pore water pressure. resistivity change rate pH value and calcium ion concentration (Ca) 2+ ; The soil parameters include dynamic stress amplitude. Cumulative loading times N, initial elastic modulus of soil and matrix suction S; The calculation module is used to calculate the cumulative plastic strain of the current solid waste aggregate layer based on the piecewise hyperbolic correction algorithm. Its rate of change and the predicted value of unconfined compressive strength (UCS); The adjustment module is used to adjust the grouting parameters based on the monitoring and calculation results of sensor parameters and soil parameters, through bidirectional control of feedforward and feedback.

9. A self-regulating cyclic reinforcement system based on collaborative MICP of construction solid waste, characterized in that, include: The matrix construction layer is composed of recycled construction waste aggregate and in-situ soil mixed according to a specific gradation. The dual-channel grouting pipe network is pre-embedded in the matrix construction layer and consists of multiple arrayed grouting units. Each grouting unit includes an inner injection pipe and an outer suction pipe. The inner injection pipe is provided with an outlet hole for injecting bacteria and cementing fluid. The outer suction pipe is provided with a permeable hole and is covered with a permeable geotextile filter layer. The circulating pumping unit includes a vacuum pump, a magnesium ammonium phosphate reaction vessel, and a circulating pump; the vacuum pump is connected to an external suction pipe. The permeation monitoring unit, located on the outer periphery of the external suction pipe, includes a micro pore water pressure gauge, a resistivity sensor, and a pH sensor. The central control unit, connected to the circulating pumping processing unit and the permeation monitoring unit, includes a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the function of the grouting control device as described in claim 8.

10. A method for construction using the self-regulating cyclic reinforcement system as described in claim 9, characterized in that, include: Solid waste aggregate pretreatment and laying; A water injection test was conducted using the dual-channel intelligent grouting pipeline network to determine the initial permeability coefficient. Combined with ground-penetrating radar data, the high-permeability zone and low-permeability zone were divided using the central control unit. The gelling agent is injected into the soil through the internal injection tube, using a pulse mode of grouting-settling-suction. After the settling reaction period, the circulation and drainage treatment module is activated to extract the reaction byproducts and unreacted waste liquid through the external suction tube. The grouting parameters are adjusted through bidirectional control of feedforward and feedback from the central control unit, as well as the grouting can be started and stopped.

Images