In-situ visual repairing method based on high-pressure rotary spraying agent migration behavior model

Abstract

The invention discloses an in-situ visual remediation method based on a high-pressure jet grouting agent migration behavior model, which is characterized by comprising the following steps: (1) establishing an agent migration behavior model for in-situ remediation of contaminated site soil based on high-pressure jet grouting, and obtaining a formula of the diffusion radius of a remediation agent; (2) on the basis of the established medicament migration behavior model, carrying out scientific and precise remediation on the polluted soil; and (3) in-situ visual repair based on a high-density resistivity imaging technology.

Description

Technical Field

[0001] The present invention belongs to the technical field of environmental pollution control, and specifically proposes an in-situ visual precision remediation method combining high-pressure rotary spraying technology with a drug migration behavior model for soil pollution remediation. The core of this method is to optimize the remediation process parameters of high-pressure rotary spraying through an accurate drug migration behavior model, and to use visualization technology for real-time monitoring and regulation to achieve efficient and precise control of soil pollution. Background Art

[0002] With economic growth, soil pollution is mainly characterized by diverse pollution types, complex causes, and obvious regional distribution characteristics. Soil pollution not only threatens the safety of agricultural products and human health, but also affects social stability and sustainable development. In view of this, effective prevention, control and remediation of soil pollution should be promoted. In the soil pollution remediation technology system, in-situ remediation technology has been widely used due to its high efficiency and flexibility. In particular, high-pressure rotary spraying in-situ remediation technology effectively improves the remediation effect and economic benefits by accurately controlling the injection point, depth and injection amount of the agent. However, in practical applications, this technology still faces the challenge of unstable remediation effect due to the difficulty in accurately predicting the diffusion radius of the agent. Problems such as uncertain agent diffusion radius and unstable remediation effect not only increase the risk and uncertainty of project implementation, but may also lead to overspending of remediation costs and extended remediation cycles, hindering the popularization and in-depth application of this technology in a wider range, and significantly restricting the timeliness and effectiveness of environmental governance.

[0003] The uncertainty of the agent diffusion radius has always been a key factor restricting the widespread application of high-pressure rotary grouting in-situ remediation technology. The lack of an accurate injection model leads to low agent injection efficiency, and it is difficult to accurately predict and precisely control the remediation range, which is the core problem of high-pressure rotary grouting remediation construction. Traditional methods rely on test piles and experience to determine the diffusion behavior of agents in the soil, but the complexity and variability of the soil environment make it difficult for this method to achieve precise control effects. Specifically, the physical and chemical properties of the soil medium, such as pore structure, permeability, and chemical reactivity, as well as unforeseen factors such as underground obstacles, will have a significant impact on the migration behavior of the agent. Therefore, relying solely on experience and test pile results to guide operations cannot accurately control the actual diffusion of the agent, which not only makes the effect of high-pressure rotary grouting in-situ remediation unstable, but may also cause ineffective consumption of resources. Summary of the invention

[0004] The present invention constructs a high-precision high-pressure rotary spray agent migration behavior model, deeply integrates agent hybrid dynamics, convection-diffusion mechanism, soil complex characteristics and equipment parameters, realizes accurate calculation of agent diffusion radius and efficient and precise injection, and successfully breaks through the core problem of uncertainty of agent diffusion radius in high-pressure rotary spray in-situ remediation technology. At the same time, the introduction of high-density electrical detection technology monitors soil resistivity changes in real time and performs three-dimensional visualization reconstruction, realizes visual monitoring of the remediation process, and improves the spatial positioning accuracy and operational controllability of the construction. More importantly, the present invention can identify underground obstacles and optimize construction sites, ensure that the agent evenly covers the contaminated area, significantly improve the efficiency and effect of remediation, and realize the soil high-pressure rotary spray remediation from "blind" construction to data-based "smart" remediation. The technical solution of the present invention is as follows:

[0005] An in-situ visual repair method based on a high-pressure rotary spray agent migration behavior model, the steps are as follows:

[0006] (1) A model of agent migration behavior for in-situ remediation of contaminated soil at contaminated sites based on high-pressure rotary spraying was established, and the formula for obtaining the diffusion radius of the remediation agent was as follows:

[0007]

[0008] Where h is the diffusion radius, m; K is the permeability coefficient, m / d; n is the number of nozzles of the pile driver, d is the diameter of the nozzle of the pile driver, m, v is the speed of the liquid agent when it is sprayed out of the nozzle, m / s, ρsoil is the soil density of the stratum where the pile driver is working, ρliquid is the density of the repair liquid agent, kg / m 3 , σ is the soil compressive strength of the stratum where the pile driver is working, kPa;

[0009] (2) Based on the established agent migration behavior model, scientific and precise remediation of contaminated soil is carried out;

[0010] (3) In-situ visual repair based on high-density resistivity imaging technology

[0011] 1) Using a multi-electrode array configuration, the electrode spacing is set to match the diffusion radius according to the calculation results of the agent migration behavior model during high-pressure rotary spray in-situ remediation, until the electrodes cover the entire contaminated area;

[0012] 4) Based on the relationship between the change in the conductivity of the contaminated soil and the concentration C of the agent after injection into the soil, an underground resistivity distribution image is constructed to determine the resistivity abnormality area;

[0013] 5) For areas with abnormal resistivity, the drilling layout of high-pressure jet grouting is adjusted and optimized based on the historical use of the land.

[0014] Furthermore, the method of step (2) is: calculate the diffusion radius of the agent, set the construction process according to the type of pollutants and the concentration of pollutants, determine the concentration of the agent and the number of injections, and carry out scientific and precise remediation of the contaminated soil.

[0015] Furthermore, in step (3), a multi-electrode array configuration is adopted, and the electrode spacing is set to match the diffusion radius according to the calculation results of the agent migration behavior model during the high-pressure rotary spray in-situ remediation process, until the electrodes cover the entire contaminated area. The specific arrangement is:

[0016] Central power supply electrode: It is arranged around the pollution source and used to send current underground;

[0017] The first circle of measuring electrodes: arranged around the central power supply electrode, used to measure the electric field changes caused by the central power supply electrode;

[0018] The second circle of power supply electrodes: located outside the first circle of measuring electrodes, used to send current into the ground to further detect the underground resistivity distribution;

[0019] The second circle of measuring electrodes are arranged around the second circle of power supply electrodes and are used to measure the electric field changes generated by the second circle of power supply electrodes;

[0020] And so on, until the electrode covers the entire contaminated area.

[0021] The present invention proposes a precise soil remediation method that combines a high-pressure rotary spraying agent migration behavior model with in-situ visualization technology. By deeply studying the agent mixing dynamics and convection diffusion mechanism in the high-pressure rotary spraying process, and considering soil characteristics and equipment parameters, a high-precision agent migration model is constructed. This model can accurately calculate the agent diffusion radius to ensure efficient and precise injection of the agent. Using high-density electrical detection technology, the soil resistivity changes are monitored in real time, and visual monitoring of the remediation process is achieved through data acquisition and three-dimensional reconstruction. The spatial positioning accuracy and operational controllability of the construction are improved. At the same time, abnormal situations are identified by analyzing the changes in soil resistivity. Based on this information, the agent diffusion radius calculated by the high-pressure rotary spraying agent migration behavior model is used to optimize the construction site, avoid or adjust the injection points around obstacles, ensure that the agent evenly covers the contaminated area, and improve the efficiency and effect of remediation. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 (a) is the conceptual diagram of high-pressure rotary grouting construction; (b) is the agent diffusion radius h calculated by the agent migration behavior model for in-situ remediation of contaminated site soil using high-pressure rotary grouting.

[0023] Figure 2 This is the layout diagram of the high-pressure rotary spraying points for contaminated soil.

[0024] Figure 3 Electrode arrangement point diagram for multi-pole electrode arrangement of soil high-density electrical method.

[0025] Figure 4 Soil resistivity map of the contaminated land before injection.

[0026] Figure 5 Soil resistivity map of the contaminated land after injection.

[0027] Figure 6 This is the soil resistivity interpretation diagram of the contaminated land before injection.

[0028] Figure 7 This is the interpretation diagram of soil resistivity after injection of pesticides in contaminated land. DETAILED DESCRIPTION

[0029] In order to further understand the content, characteristics and effects of the present invention, the specific implementation mode of the present invention is described. The basic technical scheme of the present invention is first described below:

[0030] Definition: Point arrangement refers to the placement of injection points on the surface for in-situ injection of agents within the contaminated area that requires remediation work, based on three parameters: pollution conditions, geological conditions, and the diffusion radius of the construction agent.

[0031] The in-situ visual precision repair technology based on the high-pressure rotary spray agent migration behavior model adopted by the present invention has the following steps:

[0032] (1) Agent migration behavior model based on high-pressure jet spraying for in-situ remediation of contaminated soil

[0033] The migration behavior of the agent in the process of high-pressure rotary spraying in situ remediation of contaminated soil mainly uses two modes: jet mixing and convection diffusion to achieve the mixing of the remediation agent and the contaminated soil. By establishing a high-pressure rotary spraying agent migration behavior model under the action of jet mixing and convection diffusion, the injection radius of the remediation agent during high-pressure rotary spraying in situ remediation can be accurately calculated, and the optimal rotary spraying parameters on site can be calculated according to the pollution situation of the contaminated land and the stratigraphic structure data, and the amount of agent used can be optimized to reduce ineffective investment and environmental pollution. Accurate injection of agents is achieved. The agent migration behavior model for high-pressure rotary spraying in situ remediation of contaminated site soil is shown below:

[0034]

[0035] Where h is the diffusion radius, m; K is the permeability coefficient, m / d; n is the number of nozzles of the pile driver, d is the diameter of the nozzle of the pile driver, m, v is the speed of the liquid agent when it is sprayed out of the nozzle, m / s, ρsoil is the soil density of the stratum where the pile driver is working, ρliquid is the density of the repair liquid agent, kg / m 3 , σ is the soil compressive strength of the stratum where the pile driver is constructing, kPa.

[0036] (2) In-situ visual monitoring system based on high-pressure rotary spray agent migration behavior model

[0037] In the in-situ soil remediation technology, ensuring sufficient and efficient contact between the remediation agent and the contaminated soil is the core factor that determines the remediation effect. Based on the establishment of a migration behavior model of high-pressure rotary spraying agents in contaminated site soil, the present invention adopts soil high-density electrical method (HDE), a non-invasive geophysical detection technology, to achieve accurate monitoring of the high-pressure rotary spraying remediation process. By measuring the slight changes in the current conduction characteristics in the soil, the spatial distribution of soil resistivity is indirectly reflected, thereby revealing the dynamic changes in the electrical characteristics of the soil after the injection of the agent. Combined with the data processing algorithm, key information such as the range of agent migration behavior, concentration distribution and migration dynamics are calculated from these electrical data, which can visualize and quantify the evaluation of the remediation process. This method not only improves the efficiency and accuracy of in-situ remediation, but also promotes the transformation of soil remediation from traditional "blind" construction to data-based "smart" remediation.

[0038] The injection of remediation agents will cause changes in soil resistivity. By measuring the soil resistivity in the construction area, the migration behavior of the agent in the soil can be tracked in a timely manner. At the same time, the concentration distribution of the injected agent in the soil can be calculated through the change in soil resistivity. Combined with the soil pollution situation, the remediation effect can be predicted to more accurately guide on-site remediation construction operations.

[0039] The change in the conductivity of the contaminated soil is proportional to the concentration C of the agent after injection into the soil. The calculation formula is as follows:

[0040] Δρ=ρ2-ρ1

[0041] Wherein, ρ1 is the soil conductivity before injection of the agent, Ω·m; ρ2 is the soil conductivity after injection of the agent, Ω·m; Δρ is the change in the conductivity of the contaminated soil, Ω·m.

[0042] After injecting the agent, the formula for the change of agent concentration and soil conductivity is:

[0043] Δρ=k·C

[0044] C is the mass concentration of the agent, %; k is the proportionality coefficient, which reflects the degree of influence of the agent concentration on the change of soil conductivity. Each plot is different, and the proportionality coefficient k must be experimentally measured in the contaminated plot. Through a series of soil conductivity change values ​​under different agent concentrations, k is calculated by data fitting method.

[0045] The soil resistivity measurement method is based on the multi-pole electrode arrangement method, and the electrodes are arranged with the diffusion radius h calculated by the migration behavior model of the high-pressure rotary spray in-situ remediation agent as the spacing. The specific arrangement method is:

[0046] Central power supply electrode: It is arranged around the pollution source and is used to send current underground.

[0047] The first circle of measuring electrodes: arranged around the central power supply electrode, used to measure the electric field changes caused by the central power supply electrode.

[0048] The second circle of power supply electrodes: located outside the first circle of measuring electrodes, sends current again to further detect the underground resistivity distribution.

[0049] The second circle of measuring electrodes are arranged around the second circle of power supply electrodes and are used to measure the changes in the electric field generated by the second circle of power supply electrodes.

[0050] And so on, until the electrode covers the entire contaminated area.

[0051] The advantages of this method are:

[0052] Improved resolution: Through the arrangement of multiple circles of electrodes, the underground resistivity distribution can be studied in more detail, improving the resolution of exploration.

[0053] Enhanced signal strength: Multiple turns of electrodes can produce stronger electric field signals, making it easier to detect changes in underground resistivity.

[0054] Reduce interference: Through the arrangement of multiple turns of electrodes, external interference signals can be better suppressed and the accuracy of measurement results can be improved.

[0055] The present invention collects high-precision contaminated soil resistivity data, combines inversion algorithms with imaging technology, and constructs high-resolution images of underground resistivity distribution. These images can not only intuitively display the dynamic migration process and concentration gradient of the remediation agent in the soil, but also accurately depict the underground geological structure characteristics, including potential obstacles and geological anomalies. For example, combined with the historical use of the plot, underground obstacles such as rock layers, old structures, and underground pipelines can be identified. This provides a scientific basis for the precise layout of high-pressure rotary injection points, ensuring the effectiveness and economy of the remediation work, while minimizing unnecessary construction interventions and waste of resources.

[0056] The following will be combined with the embodiments of the present invention and the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the technical solutions in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] Step 1: Based on the model of the agent migration behavior for the in-situ remediation of contaminated soil at the site by high-pressure rotary spraying, the calculation of the agent diffusion radius (h) can be found in Figure 1 , Figure 2 , the specific contents are as follows:

[0058] High-pressure rotary grouting in-situ remediation technology is to insert a grouting pipe (drill rod) with a special nozzle into the soil layer through a drill hole to a predetermined depth. Subsequently, a pre-prepared remediation agent is sprayed from the nozzle, and the grouting pipe is rotated and lifted from bottom to top while spraying. The high-pressure agent liquid cuts and stirs the soil, so that the remediation agent and the contaminated soil are fully mixed, and the pollutants are decomposed into low-toxic or non-toxic products through chemical reactions, thereby achieving the purpose of remediating the contaminated soil ( Figure 1 ).

[0059] Based on the hydrogeological report of the contaminated site, the site pollution investigation report and the parameters of the high-pressure jet grouting equipment, a total of 7 parameters, including the permeability coefficient, soil compressive strength, soil density, remediation agent density, agent injection speed, number of nozzles of the pile driver and nozzle diameter of the construction area, were selected and substituted into the agent migration behavior model of the high-pressure jet grouting in-situ remediation of the contaminated site soil to calculate the diffusion radius of the high-pressure jet grouting agent. The high-pressure jet grouting drilling holes were arranged according to the calculated agent diffusion radius ( Figure 2 ).

[0060]

[0061] Table 1 Parameters of the embodiment model:

[0062] Study parameters symbol unit Value Drug diffusion radius h m Permeability coefficient K m / d 1 Nozzle quantity n indivual 2 Nozzle diameter d m 0.002 Injection speed v m / s 200 Soil density ρ Earth <![CDATA[kg / m 3 ]]> 1.85 Repair potion density ρ liquid <![CDATA[kg / m 3 ]]> 1.35 Soil compressive strength σ kPa 0.2

[0063] Based on the calculation formula for the diffusion radius of high-pressure rotary spraying agents, the relevant parameters of the example plot take the values ​​in the above table, and the diffusion radius of the high-pressure rotary spraying agents in the example plot is calculated to be 1.5m.

[0064] Step 2: In-situ visual monitoring system based on high-pressure rotary spray agent migration behavior model. Figure 3-7 , the specific contents are as follows:

[0065] Combined with the pollution concept model of the contaminated land, with the pollution source as the center, the agent diffusion radius (1.5m) calculated according to the migration behavior model of the high-pressure rotary spraying in-situ remediation of the contaminated site soil agent is used as the electrode layout spacing, and a multi-pole electrode arrangement is adopted to evenly arrange electrodes in all directions of the pollution plume. The resistivity of the contaminated land is measured by the three-dimensional high-density electrical method, and the resistivity imaging test is carried out based on the spatial distribution of soil resistivity ( Figure 4 ). According to the resistivity imaging, the layout of high-pressure jet grouting holes can be adjusted and optimized for areas with abnormal resistivity, combined with the historical use of the land (such as buildings).

[0066] According to the migration behavior model of the in-situ injected agent, the agent diffusion radius is scientifically calculated, and the construction process is set (determining the agent concentration and the number of injections) according to the pollutant type, pollutant concentration, etc., to carry out scientific and precise remediation of the contaminated soil.

[0067] After injection, the soil resistivity of the injection area was measured again. Based on the soil resistivity imaging test ( Figure 5 ), analyze the diffusion of the agent in the soil, and realize visual supervision of the high-pressure rotary grouting construction process. The injection of the agent causes a significant change in soil resistivity (see Figure 4 , Figure 5 ), the average soil resistivity before injection was 2.84Ω·m, and the average soil resistivity after injection was 2.42Ω·m. The injection of the agent caused the resistivity of the soil system to decrease. Based on formulas (2) and (3), the k value of this example plot is 1.51. According to the soil resistivity change value of 0.42Ω·m, the average mass concentration of the agent in the soil can be calculated to be 27.81%.

[0068] Δρ=ρ2-ρ1(2)

[0069] Δρ=k·C(3)

[0070] The interpretation and analysis of soil resistivity before and after injection showed that there were three abnormal areas in the underground soil of the sample plot before injection ( Figure 6 Red area), combined with the historical use of the plot (factory building), it is preliminarily judged to be a legacy foundation. During the high-pressure rotary injection construction, the area can be appropriately densely distributed to improve the repair efficiency. After injection, the overall agent diffusion effect of this example plot is good (see Figure 7 ), but there are still two areas where the injection effect is average ( Figure 7 Yellow area), this area can be supplemented with medication to improve the quality of repair.

[0071] In summary, the present invention establishes a model of agent migration behavior for in-situ remediation of contaminated soil in contaminated sites by high-pressure rotary spraying, accurately calculates the diffusion radius of the agent in the soil during high-pressure rotary spraying construction, and uses this to arrange the construction points of high-pressure rotary spraying. During the construction process, timely monitoring of the resistivity of the contaminated soil is performed, and the invisible underground construction conditions are timely converted into a visualization model, and the actual injection of the agent is monitored from two aspects: the diffusion range of the agent and the concentration of the agent to see whether it can achieve the established goals according to the set process parameters. Achieving precise medication under different pollution concentrations, different pollutants, and different geological conditions can solve the problems of excessive medication and excessive remediation in the prior art, and achieve scientific, green, and sustainable remediation from a technical level.

Claims

1. An in-situ visual repair method based on a high-pressure rotary spray agent migration behavior model, characterized in that , the steps are as follows: (1) A model of agent migration behavior for in-situ remediation of contaminated soil at contaminated sites based on high-pressure rotary spraying was established, and the formula for obtaining the diffusion radius of the remediation agent was as follows: Where h is the diffusion radius, m; K is the permeability coefficient, m / d; n is the number of nozzles of the pile driver, d is the diameter of the nozzle of the pile driver, m, v is the speed of the liquid agent when it is sprayed out of the nozzle, m / s, ρ 土 is the soil density of the stratum where the pile driver is constructing, ρ 液 To repair the density of liquid agent, kg / m 3 , σ is the soil compressive strength of the stratum where the pile driver is working, kPa; (2) Based on the established agent migration behavior model, scientific and precise remediation of contaminated soil is carried out; (3) In-situ visual repair based on high-density resistivity imaging technology 1) Using a multi-electrode array configuration, the electrode spacing is set to match the diffusion radius according to the calculation results of the agent migration behavior model during high-pressure rotary spray in-situ remediation, until the electrodes cover the entire contaminated area; 2) Based on the relationship between the change in the conductivity of the contaminated soil and the concentration C of the agent after injection into the soil, an underground resistivity distribution image is constructed to determine the resistivity abnormality area; 3) For areas with abnormal resistivity, the drilling layout of high-pressure jet grouting is adjusted and optimized based on the historical use of the land.

2. The in-situ visual repair method based on the high-pressure rotary spray agent migration behavior model according to claim 1 is characterized in that: The method of step (2) is: calculate the diffusion radius of the agent, set the construction process according to the type of pollutants and the concentration of pollutants, determine the concentration of the agent and the number of injections, and carry out scientific and precise remediation of the contaminated soil.

3. The in-situ visual repair method based on the high-pressure rotary spray agent migration behavior model according to claim 1 is characterized in that: In step (3), a multi-electrode array configuration is used, and the electrode spacing is set to match the diffusion radius according to the calculation results of the agent migration behavior model during the high-pressure rotary spray in-situ remediation process until the electrodes cover the entire contaminated area. The specific arrangement is: Central power supply electrode: It is arranged around the pollution source and used to send current underground; The first circle of measuring electrodes: arranged around the central power supply electrode, used to measure the electric field changes caused by the central power supply electrode; The second circle of power supply electrodes: located outside the first circle of measuring electrodes, used to send current into the ground to further detect the underground resistivity distribution; The second circle of measuring electrodes are arranged around the second circle of power supply electrodes and are used to measure the electric field changes generated by the second circle of power supply electrodes; And so on, until the electrode covers the entire contaminated area.

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