A stratum grouting precise control construction method based on a multi-scale super-hydrophobic grouting material

Abstract

The application discloses a kind of based on multi-scale super-hydrophobic grouting material stratum grouting accurate control construction method, comprising the following steps: obtaining the structure characteristics and soil characteristics of to-be-grouted stratum, determine grouting reinforcement area;According to structure characteristics and soil characteristics, design grouting process parameters;According to soil characteristics and process parameters, input permeation grouting diffusion radius prediction model, calculate grouting diffusion radius and grouting quantity;Based on the predicted grouting diffusion radius, judge whether to meet the requirements of covering grouting reinforcement area;If not satisfied, then adjust grouting pressure and material ratio, re-input model iteration calculation, until meet the requirements of covering grouting reinforcement area;According to the process parameters finally determined, carry out field grouting construction;After construction is completed, carry out grouting effect detection and evaluation.The construction method of the application can predict grouting diffusion radius and grouting quantity before construction, so as to optimize the process parameters of grouting material, improve the durability and reliability of grouting body.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering seepage prevention and reinforcement, and in particular to a method for precise control of grouting construction based on multi-scale superhydrophobic grouting materials. Background Technology

[0002] Grouting materials are widely used in tunnel engineering, foundation reinforcement, and underground structure seepage prevention. However, traditional cement-based or chemical grouting materials have highly hydrophilic surfaces, making them prone to hydrolysis, freeze-thaw damage, and salt erosion in humid or water-rich environments. These grouts suffer from poor injectability, difficulty in precisely controlling the diffusion radius, and challenges in estimating the injection volume and time. Furthermore, the grouting material mix cannot be precisely matched to the construction plan, leading to easy deterioration and failure of the grouted body during its service life. These problems severely restrict the long-term durability and engineering reliability of grouted structures, necessitating the development of a construction method that combines superhydrophobicity, high injectability, and precise controllability. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a method for precise control of grouting construction based on multi-scale superhydrophobic grouting materials. This method can predict the grouting diffusion radius and grouting volume before construction, thereby optimizing the process parameters of the grouting material and improving the long-term durability and engineering reliability of the grouted solidified body.

[0004] A method for precise control of formation grouting based on multi-scale superhydrophobic grouting materials according to the present invention includes the following steps: S1: Obtain the structural and soil characteristics of the stratum to be grouted, and determine the grouting reinforcement area. The soil characteristics include at least soil porosity and soil pore diameter. S2: Based on the structural features and the soil features, design grouting process parameters, which include at least the grouting pipe insertion length, grouting pressure, grouting material ratio, and grouting time; S3: Based on the soil characteristics and the process parameters, input the permeation grouting diffusion radius prediction model to calculate the grouting diffusion radius and grouting volume; S4: Based on the predicted grouting diffusion radius, determine whether the grouting reinforcement area is covered; if not, adjust the grouting pressure and material ratio, re-enter the model for iterative calculation, until the requirement for covering the grouting reinforcement area is met. S5: Carry out on-site grouting construction according to the final determined process parameters, and simultaneously collect grouting pressure, flow rate and surface settlement data, and feed them back to the intelligent control system in real time to optimize grouting rate and pressure distribution; S6: After construction is completed, the grout body is cured and the grouting effect is tested and evaluated. The parameters tested include at least the radius of the grout body, the strength of the grout body, and the contact angle of the grout body surface.

[0005] According to the construction method of the present invention, the grouting diffusion radius and grouting volume can be predicted before construction, thereby optimizing the process parameters of the grouting material and improving the long-term durability and engineering reliability of the grouting reinforcement.

[0006] In some embodiments, the calculation formula for the permeation grouting diffusion radius prediction model in step S3 is: in, l The grouting diffusion radius is... P For grouting pressure, t This refers to the grouting time. d The diameter of the soil pores. The porosity of the soil. m This is the median value of the integral viscosity of the slurry. r For slurry density, c w The density of water, c b The bulk density of the slurry. r 0 The inner diameter of the grouting pipe. P 0 Grouting pressure at the grouting port.

[0007] In some embodiments, the median integral value of the slurry viscosity is determined by the following formula: in, (t)= , The initial viscosity, A and t 1 is a fitting constant; for the superhydrophobic grouting material, A =9.76×10 -6 , t 1=3.35, μ0=16.12.

[0008] In some embodiments, the formula for calculating the grouting volume in step S3 is: in, The porosity of the soil. l The predicted grouting diffusion radius, a The length of the grouting body.

[0009] In some embodiments, the components of the grouting material include silica sol, hydrophobic modified emulsion, and kaolin. The hydrophobic modified emulsion is a polymethylhydrosiloxane emulsion. The variation in the grouting material ratio affects the grout viscosity and gelation time.

[0010] In some embodiments, the grouting pressure in step S2 ranges from 5 kPa to 30 kPa, the grout viscosity ranges from 1 mPa·s to 10 mPa·s, and the grouting duration ranges from 0.2 to 0.5 times the gelation time.

[0011] In some embodiments, the adjustment step size of the iterative calculation in step S4 is: the grouting pressure is adjusted by 2 kPa each time, and the mass ratio of hydrophobic modified emulsion in the material ratio is adjusted by ±3% each time.

[0012] In some embodiments, the contact angle of the grout surface in step S6 is detected using a contact angle measuring instrument, the strength of the grout is detected using an unconfined compressive strength test, and the radius of the grout is detected using ground-penetrating radar.

[0013] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a flowchart of a construction method according to an embodiment of the present invention; Figure 2 This is a stress analysis diagram during the construction process of a permeation grouting diffusion radius prediction model according to an embodiment of the present invention; Figure 3 This is a rheological equation fitting curve diagram according to an embodiment of the present invention; Figure 4 This is a bar chart comparing and verifying the permeation grouting diffusion radius prediction model with measured data according to an embodiment of the present invention. Detailed Implementation

[0016] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0017] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. Additionally, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0018] Reference Figure 1 A method for precise control of formation grouting based on multi-scale superhydrophobic grouting materials includes the following steps: S1: Obtain the structural and soil characteristics of the stratum to be grouted, and determine the grouting reinforcement area. The soil characteristics include at least soil porosity and soil pore diameter. S2: Based on the structural and soil characteristics, design the grouting process parameters, which should include at least the grouting pipe insertion length, grouting pressure, grouting material ratio, and grouting time. S3: Based on the soil characteristics and process parameters, input the permeation grouting diffusion radius prediction model to calculate the grouting diffusion radius and grouting volume; S4: Based on the predicted grouting diffusion radius, determine whether the grouting reinforcement area is covered; if not, adjust the grouting pressure and material ratio, re-enter the model for iterative calculation, until the requirement for covering the grouting reinforcement area is met. S5: Carry out on-site grouting construction according to the final determined process parameters, and collect grouting pressure, flow rate and surface settlement data simultaneously, and feed them back to the intelligent control system in real time to optimize grouting rate and pressure distribution; S6: After construction is completed, the grout body is cured and the grouting effect is tested and evaluated. The parameters tested include at least the radius of the grout body, the strength of the grout body, and the contact angle of the grout body surface.

[0019] The type of stratum to be grouted is not limited. For example, it can be sandy soil, karst development layer, gravelly soil layer, cohesive soil layer, or artificial fill layer, etc. The structural characteristics of the stratum to be grouted include the layered structure, degree of fracture development, and groundwater depth, etc. The structural characteristics of the stratum to be grouted can be obtained through geological exploration, drilling sampling, and in-situ testing. The soil characteristics of the stratum to be grouted include at least soil porosity, soil pore diameter, permeability coefficient, and particle size distribution. Soil pore diameter is determined by mercury intrusion porosimetry or nitrogen adsorption method, and soil porosity is determined by image analysis method. Of course, the structural and soil characteristics of the stratum to be grouted can also include other parameters, such as the water content, compression modulus, and shear strength of the stratum. The more structural and soil characteristic parameters of the stratum to be grouted, the more accurate the characterization of the stratum to be grouted, and the more targeted and reliable the design of the grouting process parameters.

[0020] Based on the structural and soil characteristics of the stratum to be grouted, appropriate grouting process parameters are designed and selected. For example, for sandy soil strata, the grouting pressure can be set to 5 kPa~20 kPa; for artificial fill strata, the grouting pressure can be set to 10 kPa~30 kPa; for gravelly soil strata, the grouting pressure can be set to 5 kPa~10 kPa, and so on. The insertion length of the grouting pipe is determined according to the structural characteristics and fracture development degree of the stratum to be grouted. Usually, the end of the grouting pipe extends into the bottom of the grouting reinforcement area so that the final grouting reinforcement can be completely embedded in the target reinforcement layer. The grouting time depends on the local conditions. The permeability of the grouting layer and the setting of the gelling time of the grouting material are discussed. The gelling time of the grouting material can be achieved by adjusting the ratio of the grouting material. For example, the grouting material includes silica sol, hydrophobic modified emulsion and kaolin. The hydrophobic modified emulsion is a polymethylhydrosiloxane emulsion. The gelling time can be controlled by the mass ratio of the hydrophobic modified emulsion to silica sol, the amount of kaolin and the amount of gelling agent, etc. For example, a 5 mol / L NaOH solution can be used as the gelling agent to control the gelling time within the range of 60 min to 150 min, so as to allow sufficient time for grouting operation and ensure that the grouting material can fully penetrate the stratum to be grouted. For example, for sandy soil layers, the grouting time should be controlled between 15 and 30 minutes to ensure that the grouting material achieves controlled penetration and uniform filling in the target soil layer; for karst soil layers, the grouting time should be controlled between 20 and 45 minutes; for cohesive soil layers, the grouting time should be controlled between 30 and 60 minutes to overcome their low permeability and ensure effective migration of the grout; and for gravelly soil layers, the grouting time should be controlled between 10 and 25 minutes.

[0021] Thus, the selection range of grouting process parameters can be obtained according to the structural characteristics and soil characteristics of the stratum to be grouted. In combination with engineering practice, multiple groups of grouting process parameter combinations can be selected, which makes the construction scheme more implementable and adaptable, and also provides optionality and flexibility for reselecting grouting process parameter combinations in subsequent steps.

[0022] According to the soil characteristics and process parameters, input them into the permeation grouting diffusion radius prediction model to calculate the grouting diffusion radius and grouting amount. The construction process of the permeation grouting diffusion radius prediction model is as follows: 1. Basic Assumptions Based on the superhydrophobic grouting material, on the one hand, the concentration of solid particles (kaolin) added in the superhydrophobic grouting material is low, meanwhile the particle sizes of solid particles (kaolin and silica sol) in the slurry are small, so the rheological properties of the slurry are more consistent with Newtonian fluid.

[0023] The following theoretical derivation is based on the assumptions below: The slurry is an incompressible homogeneous fluid; The slurry is a Newtonian fluid, and its rheological equation conforms to the fitted expression ; The turbulent state of the slurry near the grouting hole is not considered, and the rest of the flow is laminar; The infiltration effect, slurry gravity and slurry flow pattern change during the grouting process are not considered.

[0024] 2. Equation of Motion First, based on the laminar flow theory in circular pipe, a mechanical analysis model of slurry flow is established: take a circular pipe with radius r0 as the research object, and take a fluid column with the pipe axis as the symmetry axis as the slurry micro-element, the length of the taken micro-element is dl, and the radius is r (r < r0), its force balance state is shown in Figure 2 .

[0025] The force balance relationship of the slurry micro-element is: Then the shear stress τ on the surface of the slurry micro-element can be expressed as: Where: dp is the axial pressure increment of the slurry micro-element.

[0026] Substituting the above formula into the rheological equation gives: Where: l m is the maximum diffusion distance of the slurry.

[0027] The above formula is solved by separation of variables, and a key boundary constraint condition is introduced: when the inner diameter of the pipe is infinitely small, the radius of the slurry micro-element is equal to the inner diameter of the pipe, that is, r=r0, and the flow velocity v at the pipe boundary is 0. Then we can obtain: The flow rate through a circular pipe of radius r0 per unit time is: Will v Substituting into the above formula, we get: The average flow velocity of the slurry inside the circular pipe can be expressed as: In permeation grouting in porous media, under the same stress conditions for fluid micro-elements, the fluid permeation velocity can be expressed as: in: Porosity is the porosity of the porous medium.

[0028] 3. Control equation for diffusion radius of infiltration grouting Based on Darcy's flow theory, the fluid transport rate in porous media can be characterized by the following constitutive relation: in: K is the permeability coefficient; i is the pressure gradient, i.e. ; It is the density of water.

[0029] Based on permeability coefficient and permeability k The relationship is: Wherein: γ b This is the bulk density of the slurry.

[0030] Substituting, we get: The permeability expression for porous media is obtained using the flow resistance model, which assumes that... k yes Re Functions: in: Re It is the Reynolds number; r The density of the slurry; d The initial pore diameter of the porous medium.

[0031] Slurry diffusion distance is l At that time, the amount of grout injected Q and grouting area A They can be represented as: in, a The length of the grouting body.

[0032] Combining the above equations, we get: Grouting time t Grouting volume inside By combining the equations, we can obtain: Integrate the above equation and substitute the boundary conditions. p = p 0, l = r 0 means the pressure at the grouting port is the grouting pressure, therefore: Will Q and k Substituting into the above equation, we obtain the diffusion control equation for permeation grouting that considers the influence of grout flow resistance on soil permeability: in, l The grouting diffusion radius is... P For grouting pressure, t This refers to the grouting time. d The diameter of the soil pores. The porosity of the soil. m This is the median value of the integral viscosity of the slurry. r For slurry density, c w The density of water, c b The bulk density of the slurry. r 0 The inner diameter of the grouting pipe. P 0 Grouting pressure at the grouting port.

[0033] The median integral of the slurry viscosity is determined by the following formula: in, (t)= That is, the rheological equations conform to the fitted expression. , The initial viscosity, A and t 1 is the fitting constant; for superhydrophobic grouting materials, A =9.76×10 -6 , tI = 3.35, μ0 = 16.12, refer to the specific fitting data. Figure 3 .

[0034] Therefore, the diffusion control equation for permeation grouting that simultaneously considers the time-varying characteristics of permeability change and grout viscosity is obtained: The formula for calculating the grouting volume in step S3 is: in, The porosity of the soil. l The predicted grouting diffusion radius, a The length of the grouting body.

[0035] Therefore, based on the structural and soil characteristics of the stratum to be grouted, the grouting reinforcement area is determined. Based on the predicted grouting diffusion radius, it is determined whether the grouting reinforcement area is covered. If not, the grouting process parameters are reselected within the range of grouting process parameters, that is, the grouting pressure and material ratio are adjusted, and the model is re-entered for iterative calculation until the requirements for covering the grouting reinforcement area are met.

[0036] In the above technical solution, the diffusion radius prediction model of permeation grouting can predict the diffusion radius of permeation grouting and estimate the required grouting volume, thereby determining whether the selected grouting process parameters can achieve full coverage of the target reinforcement range, thus optimizing the construction plan, reducing material waste and disturbance to the soil. Compared with the extensive traditional experience-based grouting construction, it significantly improves the accuracy and controllability of the stratum reinforcement, and enhances the long-term durability and engineering reliability of the grouting reinforcement.

[0037] In some embodiments, on-site grouting is carried out according to the final determined process parameters, and grouting pressure, flow rate, and surface settlement data are collected simultaneously and fed back to the intelligent control system in real time to optimize the grouting rate and pressure distribution. For example, when the grouting pressure fluctuation exceeds a threshold of 5%, the intelligent control system adjusts the grouting pump speed to stabilize the grouting pressure; or, if surface settlement is detected, the intelligent control system automatically reduces the grouting rate and verifies the ground response in stages to ensure construction safety during the grouting process.

[0038] In some embodiments, the grouting material composition includes silica sol, hydrophobically modified emulsion, and kaolin. The hydrophobically modified emulsion is a polymethylhydrosiloxane emulsion. Variations in the grouting material composition affect the grout viscosity and gelation time. For example, the average particle size of the kaolin is 2-4 μm, and the average particle size of the silica particles in the silica sol is 10-16 nm. Thus, with kaolin as the framework and nano-silica particles filling the gaps, a micro-nano hierarchical rough structure is constructed. Polymethylhydrosiloxane undergoes in-situ hydrolysis in an alkaline silica sol environment to generate silanol groups, which chemically condense and graft with the hydroxyl groups on the surface of the micro-nano particles, causing the hydrophobic methyl groups to align outwards, significantly reducing surface energy and achieving a stable hydrophobic state. This endows the grouting material with long-term impermeability and interfacial self-adaptation capabilities under complex hydrogeological conditions, reducing water penetration, freeze-thaw damage, and salt erosion in humid or water-rich environments, and improving the long-term durability and engineering reliability of the grouted body.

[0039] In some embodiments, the grouting pressure ranges from 5 kPa to 20 kPa, the grout viscosity ranges from 1 mPa·s to 10 mPa·s, and the grouting time ranges from 0.2 to 0.5 times the gelation time. For example, the grouting pressure can be 5 kPa, 7 kPa, 9 kPa, 10 kPa, 12 kPa, 14 kPa, 15 kPa, 16 kPa, 18 kPa, or 20 kPa, with different grouting pressures corresponding to the adaptability requirements of different permeability formations; the grout viscosity can be 1 mPa·s, 2 mPa·s, 3 mPa·s, 4 mPa·s, 5 mPa·s, 6 mPa·s, 7 mPa·s, 8 mPa·s, 9 mPa·s, 10 mPa·s, etc., with different grout viscosities corresponding to different formations and matching the permeation rate, while the typical viscosity range of traditional cement grout is 100 mPa·s. The range of mPa·s to 2000 mPa·s indicates that the grouting material has good fluidity and can adapt to more geological environments. The grouting time ranges from 0.2 to 0.5 times the gelation time. This is because different grouting material ratios result in a large variation in gelation time, thus allowing for a wider selection range for the grouting time. The grouting time should ideally be 0.2 to 0.5 times the gelation time to ensure that grouting is completed before the grouting material begins to gel, thereby preventing the grout body from deteriorating and failing during its service life.

[0040] In some embodiments, the adjustment step size of the iterative calculation in step S4 is: the grouting pressure is adjusted by 2 kPa each time, and the mass ratio of hydrophobic modified emulsion in the material ratio is adjusted by ±3% each time. For example, in the permeation grouting construction of sandy soil layers, the grouting pressure can be set to 5 kPa~20 kPa. If a grouting pressure of 10 kPa is selected, and the theoretical diffusion radius calculated according to the permeation grouting diffusion radius prediction model cannot cover the target reinforcement range, the grouting pressure can be increased to 12 kPa, and the theoretical diffusion radius can be calculated again. If it is still not satisfied, it can be finely adjusted to 14 kPa until the deviation between the theoretical diffusion radius and the measured value is less than 5%. According to the theoretical diffusion radius calculated by the permeation grouting diffusion radius prediction model, the required grouting volume is calculated. According to the grouting volume, the predicted grouting time can be calculated. If the time exceeds the upper limit of the gelation time of the grouting material, the grouting pressure and material ratio need to be optimized simultaneously to ensure that the grout completes diffusion and solidification within the effective time, thereby ensuring that the grout body is uniformly filled and densely formed in the target area. For example, the mass ratio of the hydrophobic modified emulsion can be adjusted. Alternatively, the mass ratio of silica sol and kaolin, or the amount of gelling agent added, can be adjusted to optimize the gelation time of the grout. For instance, increasing the mass ratio of the hydrophobic modified emulsion by 3% can optimize the gelation time and the hydrophobic properties of the grouting material.

[0041] In some embodiments, the contact angle of the grout surface in step S6 is detected using a contact angle measuring instrument, the strength of the grout is detected using an unconfined compressive strength test, and the radius of the grout is detected using ground-penetrating radar. The grout sample can be obtained through drilling or in-situ testing. After construction, the grout is cured, and the grouting effect is tested and evaluated. The parameters tested include the grout radius, grout strength, and grout surface contact angle. This allows for a comprehensive evaluation of the grout's permeability suppression capacity, mechanical bearing capacity, and superhydrophobic stability, thereby verifying its long-term protective effectiveness under complex hydrogeological conditions. This provides a scientific basis and practical feedback for optimizing the precise control construction method for grouting in formations based on multi-scale superhydrophobic grouting materials of this invention.

[0042] The effectiveness of the permeation grouting diffusion radius prediction model of the present invention is verified by laboratory simulation method.

[0043] The infiltration grouting process of nanocomposite superhydrophobic grouting materials in sandy soil strata was simulated using a self-designed indoor horizontal infiltration grouting system. This system allows for real-time monitoring of grouting pressure and changes in excess pore water pressure during the grouting process, as well as observation of surface displacement. The specific experimental grouting process is as follows: (1) Backfilling. First, apply Vaseline around the model barrel to ensure good adhesion between the soil and the barrel wall, preventing the sidewalls from becoming a dominant channel for water during grouting. Before backfilling, mix the prepared soil with a certain particle size distribution and a certain amount of water evenly, controlling the moisture content to 5%. Backfilling is carried out using a layered compaction method, with each layer containing 7.6 kg of dry soil, compacted using a compaction hammer, controlling the soil layer height to 5 cm. After compaction, water is sprinkled on the surface to increase the soil moisture content. After all the water has seeped into the soil, the moisture content of the central soil is measured. Before backfilling the next layer, the surface of the previous layer of soil is roughened to prevent stratification. The soil is left to stand for 24 hours after backfilling before the test begins, ensuring that all excess pore water pressure generated during compaction dissipates.

[0044] (2) Installation of grouting pipes and pore water pressure gauges. During the backfilling process, grouting pipes are installed in the corresponding soil layers to ensure that the grouting pipes are centered in the model bucket. Pore water pressure gauges are installed within the corresponding burial depth range, with the pore water pressure gauge leads extending out of the soil through the upper surface of the soil.

[0045] (3) Preparation of grout. In order to avoid the grout from gelling during the grouting process and clogging the pipe, and to ensure the grouting effect, a grout with a test gelling time of 131 minutes was selected. Sufficient time was reserved for the test, and it can also avoid the grout from seeping under gravity after the grouting is completed due to excessive gelling time.

[0046] (4) Check the pipeline. Before the test begins, check the airtightness of the slurry storage tank and the sealing of the pipeline by injecting water.

[0047] (5) Data acquisition. Set the pore water pressure gauge reading to zero and start data acquisition (the obtained pore water pressure is the excess pore water pressure caused by grouting); record the initial reading of the laser displacement gauge and record the laser displacement gauge reading using a camera.

[0048] (6) Start grouting. Fill the grout storage tank with grout and tighten the bolts on the tank lid to seal it. Turn on the switch at the bottom of the storage tank and adjust the vacuum pump knob to reach the target grouting pressure. Record the change in grout mass and grouting pressure every 30 seconds during the test. Grouting ends when the grout mass no longer changes.

[0049] (7) Stop grouting. To better reflect the actual project, after grouting is completed, pull out the grouting pipe and plug the holes on the model bucket with rubber stoppers to prevent grout from flowing out. Continue to monitor pore water pressure and surface displacement. Clean the pipeline to prevent grout from gelling in the pipeline and clogging it.

[0050] (8) Post-test processing. Data acquisition was stopped once the readings of the pore water pressure gauge and laser displacement gauge stabilized. The grouted sand was cured in air at 20℃ for 28 days, samples were removed, and the dimensions of the grouting body were measured. The grouting body was scanned in three dimensions using the RealityComposer mobile app, and the scanned file was digitally modeled to calculate the volume of the scanned body.

[0051] Table 1 shows the experimental results of the grouting parameters for the five groups of experiments.

[0052] Table 1. Test results of grouting parameters

[0053] Based on the relevant experimental parameters of the model test, the calculation parameters of the permeation grouting diffusion radius prediction model are shown in Table 2. Since the soil layer is thin and the soil is unsaturated, the initial water pressure p0 is small and can be ignored in the calculation. The initial soil pore diameter, which was not obtained in the experiment, can be calculated by substituting the soil permeability and porosity into the expression for porous media permeability at the initial time, i.e., t=0, l=0. The calculation results are shown in Table 3. A comparison is made between the calculated analytical solution and the experimental results. Figure 4 As shown, the theoretical solutions in the first and second groups are very close to the actual grouting radii, demonstrating the effectiveness of the model. The theoretical solutions in groups 3-5 are higher than the actual values, mainly because the model experiment involved horizontal grouting, which allows the grout to spread more easily along the grouting pipe, resulting in a grout length greater than the grouting range, thus confirming this hypothesis. Compared to using traditional cement-based materials and relying on construction experience and other known methods to predict the grouting radius of this type of soil (with a minimum error of 170%-180%), the prediction accuracy of this patent is improved by 2-3 times (with the error from the theoretical solution controlled within 50%), proving the effectiveness of the theoretical model.

[0054] Table 2 Calculation parameters of the theoretical model

[0055] Table 3 Initial soil pore diameter values

[0056] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0057] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for precise control of formation grouting construction based on multi-scale superhydrophobic grouting materials, characterized in that, Includes the following steps: S1: Obtain the structural and soil characteristics of the stratum to be grouted, and determine the grouting reinforcement area. The soil characteristics include at least soil porosity and soil pore diameter. S2: Based on the structural features and the soil features, design grouting process parameters, which include at least the grouting pipe insertion length, grouting pressure, grouting material ratio, and grouting time; S3: Based on the soil characteristics and the process parameters, input the permeation grouting diffusion radius prediction model to calculate the grouting diffusion radius and grouting volume; S4: Based on the predicted grouting diffusion radius, determine whether the grouting reinforcement area is covered; if not, adjust the grouting pressure and material ratio, re-enter the model for iterative calculation, until the requirement for covering the grouting reinforcement area is met. S5: Carry out on-site grouting construction according to the final determined process parameters, and simultaneously collect grouting pressure, flow rate and surface settlement data, and feed them back to the intelligent control system in real time to optimize grouting rate and pressure distribution; S6: After construction is completed, the grout body is cured and the grouting effect is tested and evaluated. The parameters tested include at least the radius of the grout body, the strength of the grout body, and the contact angle of the grout body surface.

2. The method for precise control of formation grouting construction based on multi-scale superhydrophobic grouting materials according to claim 1, characterized in that, The calculation formula for the permeation grouting diffusion radius prediction model in step S3 is as follows: in, l The grouting diffusion radius is... P The grouting pressure is t, and the grouting time is t. δ The diameter of the soil pores. The porosity of the soil. μ This is the median value of the integral viscosity of the slurry. ρ For slurry density, γ w The density of water, γ b The bulk density of the slurry. r 0 The inner diameter of the grouting pipe. P 0 Grouting pressure at the grouting port.

3. The method for precise control of formation grouting based on multi-scale superhydrophobic grouting materials according to claim 2, characterized in that, The median integral value of the slurry viscosity is determined by the following formula: in, ( t )= , The initial viscosity, A t1 and t1 are fitting constants; for the superhydrophobic grouting material, A =9.76×10⁻⁶, t 1 = 3.35 μ 0 = 16.

12.

4. The method for precise control of formation grouting construction based on multi-scale superhydrophobic grouting materials according to claim 2, characterized in that, The formula for calculating the grouting volume in step S3 is: in, The porosity of the soil. l The predicted grouting diffusion radius, a The length of the grouting body.

5. The method for precise control of formation grouting construction based on multi-scale superhydrophobic grouting materials according to claim 2, characterized in that, The components of the grouting material include silica sol, hydrophobic modified emulsion, and kaolin. The hydrophobic modified emulsion is a polymethylhydrosiloxane emulsion. The variation in the grouting material ratio affects the grout viscosity and gelation time.

6. The method for precise control of formation grouting construction based on multi-scale superhydrophobic grouting materials according to claim 5, characterized in that, The grouting pressure ranges from 5 kPa to 30 kPa, the grout viscosity ranges from 1 mPa·s to 10 mPa·s, and the grouting duration ranges from 0.2 to 0.5 times the gelation time.

7. A method for precise control of formation grouting construction based on multi-scale superhydrophobic grouting materials according to claim 5 or 6, characterized in that, The adjustment step size of the iterative calculation in step S4 is as follows: the grouting pressure is adjusted by 2 kPa each time, and the mass ratio of hydrophobic modified emulsion in the material ratio is adjusted by ±3% each time.

8. The method for precise control of formation grouting construction based on multi-scale superhydrophobic grouting materials according to claim 1, characterized in that, In step S6, the contact angle of the grout surface is detected using a contact angle measuring instrument, the strength of the grout is detected using an unconfined compressive strength test, and the radius of the grout is detected using ground-penetrating radar.

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