Microcapsule type water glass for double-slurry grouting as well as preparation method and application of microcapsule type water glass

Abstract

The invention discloses microcapsule type water glass for double-slurry grouting and a preparation method and application thereof.The method comprises the steps that water glass is packaged in a controllable release capsule, the water glass and cement slurry are injected into a drill hole together, the capsule is dissolved or broken at a preset position, the water glass is released and fully mixed with the cement slurry, then solidification is conducted, and a solidified body is formed; coal and rock strata are reinforced. The slurry mixing uniformity is effectively improved, early coagulation is prevented, the construction process is simplified, the grouting effect is improved, dynamic regulation and control of the slurry coagulation time are achieved, the applicability is high, and the method can be widely applied to the fields of coal and rock stratum reinforcement, mine water prevention and control, tunnel and underground engineering, water conservancy and hydropower, environmental protection, municipal administration and the like.

Description

Microcapsule-type water glass for dual-slurry grouting, its preparation method and application Technical Field

[0001] This invention belongs to the fields of coal and rock strata reinforcement and mine water control, and relates to a microcapsule-type water glass for dual-slurry grouting, its preparation method and application. Background Technology

[0002] In the production processes of coal mines and non-coal mines, underground mines and open-pit mines, as well as in the construction of water conservancy, hydropower, environmental protection, and municipal projects, any excavation involving underground space will inevitably expose or disturb underground aquifers and surface water bodies to varying degrees. This can lead to groundwater and surface water entering the underground production space, causing water inrushes. This can range from affecting production to causing casualties, with coal mines facing the most severe water hazard problems. To effectively control mine water inrushes and ensure mine water safety, coal mines mainly carry out "exploration, prevention, blocking, dredging, drainage, interception, and monitoring" work. Injecting grout into rock fissures or broken rock layers through drilling can achieve the purpose of water blocking and reinforcement. After comparing the application effects of various construction techniques, cement-water glass can effectively seal the fissures in the rock and soil, blocking the seepage path of groundwater. The use of non-toxic, harmless cement-water glass grout with controllable setting time or other new chemical materials as grouting materials is becoming increasingly common.

[0003] Drilling grouting constructs linear grouting channels in thick rock formations through surface straight holes, surface directional horizontal holes, or underground horizontal holes. Grout is injected into the borehole using a grouting pump, and then the grout spreads along the cracks or cavities exposed by the borehole to seal the water passages in the rock formation. However, existing dual-grouting technology, especially cement-water glass dual-grouting, has some significant defects: (1) Early setting: After the dual grouts are mixed at the borehole opening, they may begin to set during transport. Especially in grouting projects with large hole depths, due to the long grout transport distance, the mixed dual grouts may solidify in the borehole before being injected into the cracks of the rock and soil, which may block the borehole, prevent the grout from reaching the predetermined grouting section, affect the quality of the project, and even cause safety accidents.

[0004] (2) Uneven mixing of grout: Traditional dual-grout grouting requires the use of a special mixer at the borehole opening for mixing. Even with specialized equipment, it is difficult to ensure uniform mixing of the two grouts within the borehole, affecting the final reinforcement effect. Some areas may only contain a single grout, failing to leverage the synergistic effect of the two grouts and thus failing to achieve the expected strength and durability. Furthermore, uneven mixing can lead to a loose structure in the consolidated body, with pores and defects, increasing the risk of groundwater leakage and affecting the effectiveness of water control.

[0005] (3) High construction difficulty: The existing dual-slurry grouting technology has high requirements for construction process, which increases the construction difficulty and cost. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a microcapsule-type water glass for dual-slurry grouting, its preparation method, and its application. Water glass is encapsulated within a capsule, and by controlling the capsule's release performance, delayed mixing of the water glass and cement slurry is achieved. This solves the problems of early setting, borehole blockage, and uneven slurry mixing affecting reinforcement effects in existing borehole dual-slurry grouting methods. It is particularly effective for deep or long-distance grouting projects where the slurry delivery distance is large, effectively preventing borehole blockage accidents caused by mixed slurry, and improving grouting effect, construction efficiency, and project quality.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a microcapsule-type water glass for dual-slurry grouting, comprising a water glass solution and a shell encapsulating the water glass solution; the shell is a biodegradable or soluble material that can slowly dissolve or rupture in a cement slurry environment to release the water glass.

[0008] The present invention also includes the following technical features: Specifically, the shell material is selected from natural polymers, synthetic polymers, inorganic materials or mixtures thereof, including polylactic acid, polyvinyl alcohol, gelatin, sodium alginate, chitosan, starch, polyacrylate, silicon dioxide, and calcium carbonate.

[0009] The method for preparing microcapsule-type water glass for dual-slurry grouting includes the following steps: Step 1, preparing water glass solution: dissolving water glass in water to prepare a water glass solution of the required concentration; Step 2, preparing capsule shell: preparing shell material using physical or chemical methods to obtain hollow capsules; Step 3, filling with water glass solution: filling the prepared water glass solution into the hollow capsules; Step 4, drying / curing: drying or curing the filled capsule-type water glass.

[0010] Specifically, the physical methods include dripping, spray drying, complex condensation, and solvent evaporation; the chemical methods include interfacial polymerization and in-situ polymerization.

[0011] Specifically, the steps include: preparing a 40% concentration water glass solution; using polylactic acid as the shell material, dissolving polylactic acid in dichloromethane to prepare a 5% polylactic acid solution; dropping the polylactic acid solution into the water glass solution to form droplets of polylactic acid encapsulating water glass; and drying at 40°C for 24 hours to obtain capsule-shaped water glass.

[0012] Specifically, the capsule diameter is controlled at 1-2 mm, and the wall thickness is 0.1-0.2 mm.

[0013] The method for preparing microcapsule-type water glass for dual-slurry grouting involves injecting the capsule-type water glass and cement slurry together into a borehole. The capsule-type water glass slowly dissolves or ruptures in the grouting hole section, releasing water glass, which mixes thoroughly with the cement slurry, and then solidifies to form a consolidation layer.

[0014] Specifically, the application of the microcapsule-type water glass in dual-slurry grouting includes: preparation: confirming the geological conditions of the coal and rock strata in the construction area, selecting grouting equipment and materials, and preparing capsule-type water glass and cement slurry; drilling operation: using a drilling rig to perform drilling operations at predetermined locations, ensuring that the diameter and depth of the borehole meet the design requirements; grouting operation: injecting the capsule-type water glass and cement slurry together into the borehole, where the capsule-type water glass slowly dissolves or ruptures, releasing water glass and fully mixing with the cement slurry; slurry solidification: after the water glass and cement slurry are mixed in the grouting section, they are solidified to form a solidified layer.

[0015] Specifically, the application of microcapsule-type water glass in dual-slurry grouting includes: Preparation: Confirming the geological conditions of the coal seam in the construction area, selecting grouting equipment and materials, and preparing capsule-type water glass and cement slurry with a water-cement ratio of 0.5:1; Drilling operation: Drilling a hole with a diameter of 100mm and a depth of 50m; When probing for water at locations where the expected water pressure is greater than 0.1MPa, pre-solidifying the casing and installing gate valves, and conducting a pressure resistance test on the water-stop casing, with a pressure resistance value not less than 1.5 times the expected hydrostatic pressure; Grouting operation: Mixing the prepared capsule-type water glass with cement slurry at a volume ratio of 1:4. The grout is injected into the borehole simultaneously; the grouting pressure is controlled at 2 MPa and the grouting speed at 30 L / min; during the grouting process, the grouting pressure and speed are adjusted according to the borehole depth and geological conditions to ensure that the capsule can smoothly reach the target grouting section; grout solidification: after the grout fills the borehole, the borehole opening is sealed; the settling time is adjusted according to the release time of the capsule to allow the capsule to slowly dissolve at the target position and release water glass to fully mix with the cement grout; the settling time is adjusted according to the actual situation to ensure that the grout is fully solidified; effect observation: 7 days after the completion of grouting, the formation of the consolidation layer is observed by core sampling and compressive strength testing.

[0016] Specifically, the microcapsule-type water glass is used in dual-slurry grouting applications, and the release of the capsules is controlled by at least one of the following factors: the thickness, composition, degree of cross-linking, and porosity of the shell material, as well as the pH value and temperature of the grouting environment.

[0017] Compared with the prior art, the present invention has the following technical effects: the present invention avoids the problems of uneven mixing and early setting caused by the mixing of grout at the orifice, ensures that water glass and cement grout are mixed at the predetermined position, improves the grouting effect, simplifies the construction process, and reduces the construction difficulty and cost.

[0018] In this invention, the mixing method is as follows: the capsule-shaped slurry is encapsulated inside a capsule and injected into the borehole separately from the cement slurry; the mixing timing is as follows: the slurry components are mixed within the grouting section, rather than at the borehole opening.

[0019] This invention prevents early coagulation: by encapsulating the reactive slurry components in capsules, delayed mixing is achieved, effectively preventing the slurry from coagulating during transportation and ensuring that the slurry reaches the target area smoothly.

[0020] This invention can improve the grouting effect: it ensures the uniform mixing of grout components and their smooth arrival at the target area, thereby improving the grouting effect and enhancing the strength and impermeability of the target area.

[0021] This invention simplifies the construction process: it eliminates the need for complex mixing equipment and process control, simplifies the operation process, reduces construction difficulty and cost, and improves construction efficiency.

[0022] This invention has wider applicability: it is not limited by the depth of the grouting hole and is suitable for various complex geological conditions, especially for deep or long-distance grouting projects, and has a broader application prospect.

[0023] The present invention provides controllable setting time: by selecting appropriate capsule materials and adjusting their release properties, the setting time of the slurry can be precisely controlled to meet the needs of different projects.

[0024] This invention can achieve multiple functions: by encapsulating different slurry components or additives, it can achieve a variety of functions, such as reinforcement, water plugging, seepage prevention, expansion, and slowing down.

[0025] This invention encapsulates some grout components or additives within capsules and controls their release properties, thereby achieving delayed mixing of grout components and controlled release of active ingredients. This fundamentally solves the problems of early coagulation and uneven mixing in traditional grouting methods, and enables dynamic control of grout coagulation time. This improves grouting effect, simplifies construction process, and expands the applicability of grouting technology. Attached Figure Description

[0026] Figure 1 is a schematic diagram of the structure of capsule-shaped water glass.

[0027] Figure 2 is a flowchart of the preparation process of capsule-shaped water glass.

[0028] Figure 3 is a schematic diagram of the application of capsule-type water glass in dual-slurry grouting.

[0029] Figure 4 shows an application diagram.

[0030] The meanings of the labels in the diagram are as follows: 1. Capsule-type water glass, 2. Outer shell, 3. Inner core, 10. Sealer, 20. Drill hole, 30. Cement grout section, 40. Mixing section. Detailed Implementation

[0031] This invention provides a microcapsule-type water glass for dual-slurry grouting, comprising a water glass solution and an outer shell encapsulating the water glass solution; the outer shell is made of a biodegradable or soluble material that can slowly dissolve or rupture in a cement slurry environment to release the water glass. Specifically, as shown in Figure 1, the capsule-type water glass 1 includes an outer shell 2 and an inner core 3; wherein, the inner core is a water glass solution, the concentration of which can be adjusted according to specific engineering requirements; the outer shell is made of a biodegradable or soluble material.

[0032] In this invention, the outer shell material is selected from natural polymers, synthetic polymers, inorganic materials or mixtures thereof, including polylactic acid (PLA), polyvinyl alcohol (PVA), gelatin, sodium alginate, chitosan, starch, polyacrylate, silicon dioxide, and calcium carbonate; its function is to encapsulate the water glass and control the release time and location of the water glass.

[0033] The selection of shell material meets the following conditions: it remains stable during storage and transportation and is not easily damaged; it can slowly dissolve or break in the cement slurry environment to ensure that the water glass is released only after reaching the target grouting hole section.

[0034] This invention also provides a method for preparing microcapsule-type water glass for dual-slurry grouting, as shown in Figure 2, comprising the following steps: Step 1, preparing water glass solution: dissolving water glass in water to prepare a water glass solution of the required concentration; Step 2, preparing capsule shell: preparing shell material using physical or chemical methods to obtain hollow capsules; physical methods include dripping method, spray drying method, complex coagulation method, and solvent evaporation method; chemical methods include interfacial polymerization method and in-situ polymerization method; Step 3, filling water glass solution: filling the prepared water glass solution into the hollow capsules; Step 4, drying / curing: drying or curing the filled capsule-type water glass.

[0035] In this invention, the type of shell material, the concentration of the water glass solution, and the structure of the shell are adjusted according to specific engineering requirements in order to control the degradation rate of the capsule and the release time of the water glass.

[0036] (1) In this invention, the shell material corresponds to different engineering requirements: Polylactic acid (PLA): biodegradable, suitable for projects with high environmental protection requirements and where it is desired that the capsule can degrade and release water glass quickly after grouting, such as urban underground engineering and environmentally friendly tunnel grouting. This type of material has high water solubility or a fast biodegradation rate, which can quickly dissolve and release water glass in a short time, effectively shorten the grout setting time, quickly seal cracks, and prevent groundwater seepage.

[0037] Polyvinyl alcohol (PVA): It has good water solubility and is suitable for shallow grouting projects that require rapid release.

[0038] Gelatin and sodium alginate: natural materials suitable for environmentally sensitive geological reinforcement projects requiring moderate release rates.

[0039] Chitosan and starch: bio-based polymer materials suitable for long-term reinforcement projects requiring slow-release properties. These materials have low water solubility and slow biodegradation characteristics, which can prolong the water glass release process, maintain the activity time of the slurry, promote uniform solidification, and prevent early slurry coagulation and borehole blockage, making them suitable for large-scale, long-term engineering reinforcement.

[0040] Inorganic materials such as polyacrylate, silica, and calcium carbonate are mainly used in deep high-pressure grouting projects that require high-strength sealing and slow degradation.

[0041] High-strength shell materials (such as polylactic acid PLA, polyacrylate, inorganic materials such as silica and calcium carbonate) are mainly used in deep high-pressure environments or special complex geological conditions. The capsule is required to have strong mechanical stability and pressure resistance to prevent premature rupture during grouting and transportation, ensure that the capsule can withstand environmental pressure, release water glass according to the designed sequence, and achieve precise control.

[0042] Table 1 below shows the quantitative evaluation of the performance of microcapsule shell materials.

[0043] Table 1 Quantitative Evaluation of Microcapsule Shell Material Performance

[0044] (2) In this invention, the concentration of water glass solution is selected based on the following criteria: the selection of concentration mainly considers the fluidity of the slurry, the setting time and the final solidification strength requirements.

[0045] High concentration (water glass content approximately 40%-50%): suitable for projects requiring rapid setting and high-strength consolidation, such as mine water control and rock strata reinforcement.

[0046] Medium concentration (approximately 20%-40%): suitable for grouting needs under general geological conditions, balancing grouting fluidity and setting properties.

[0047] Lower concentrations (below 20%): Used in projects requiring longer mixing and diffusion times to slow down the setting rate, such as reinforcing micro-cracks in large underground spaces.

[0048] (3) In this invention, in addition to spherical, common shapes of the outer shell structure include ellipsoid, cylinder, oblate spheroid, polygon (such as polyhedron), etc.

[0049] Spherical: Simple to manufacture, dissolves evenly, and suitable for general grouting projects.

[0050] The capsules are micro-sized; the micro-capsule size design takes into account release rate, mechanical stability and injection flowability.

[0051] Capsule diameter: For fractures, the capsule size should generally be less than 70%-80% of the maximum fracture width to allow the capsule to enter the fracture for effective release. If the fracture width in the target rock layer is in the range of 2-5mm, the capsule diameter should be designed to be around 1-1.5mm. If the fracture is even smaller (sub-millimeter level), smaller capsules (0.2-0.5mm in diameter) or nanocapsules are required to ensure grout coverage.

[0052] Capsule thickness: The wall thickness is generally 0.1-0.2 mm, balancing mechanical strength and controllable solubility. The thinner the wall, the easier it is for the capsule to rupture or dissolve under grouting pressure and formation hydraulic action, resulting in more timely release.

[0053] During the design process, the capsule size and wall thickness are determined comprehensively by taking into account the formation porosity distribution, fracture width, grouting pressure, and grout rheology.

[0054] (4) In this invention, the degradation rate and release time of the capsule are controlled: the chemical composition and molecular structure of the shell material determine its solubility and biodegradation rate. Materials with high crystallinity and cross-linking degree degrade slowly and have a long release time; while materials with low crystallinity or easy hydrolysis release quickly.

[0055] Shell thickness and porosity: The greater the thickness, the longer the release time; the higher the porosity, the faster the water penetrates and the faster the degradation.

[0056] Degree of cross-linking of the outer shell: Materials with a high degree of cross-linking are more stable and degrade more slowly; materials with a low degree of cross-linking are more easily dissolved.

[0057] The concentration of water glass solution affects the internal pressure and dissolution rate of the slurry; a higher concentration results in a faster release rate, and vice versa.

[0058] External factors such as pH, temperature, and ion concentration in the shell and cement slurry environment also affect the degradation behavior and dissolution rate of the shell material.

[0059] Table 2 Factors affecting degradation and release

[0060] Table 2 shows the relationship between shell material, thickness, degree of cross-linking, water solubility, degradation time, and release time.

[0061] Higher cross-linking degree results in lower porosity, a denser capsule structure, hindered water permeation, and prolonged degradation and release time. Materials with higher water solubility have capsules that dissolve easily in water, leading to shorter degradation times and faster release. Thickness directly determines the length of the capsule wall's permeation path; greater thickness results in longer degradation times. Environmental factors such as pH (acidity accelerates the degradation of some biodegradable materials), temperature (high temperatures accelerate the reaction), and ionic strength all significantly affect capsule degradation. Material performance is screened and adjusted based on typical engineering site environments.

[0062] Table 3 shows the relationship between microcapsule particle size, wall thickness and release time.

[0063] Table 3. Relationship between microcapsule particle size, wall thickness and release time

[0064] The present invention relates to a method for preparing microcapsule-type water glass for dual-slurry grouting. The microcapsule-type water glass prepared is applicable to grouting projects in fields such as coal and rock strata reinforcement, mine water control, tunnels and underground engineering, water conservancy and hydropower, environmental protection, and municipal engineering. The method involves injecting the capsule-type water glass and cement slurry together into a borehole. The capsule-type water glass slowly dissolves or ruptures in the grouting hole section, releasing water glass, which mixes thoroughly with the cement slurry, and then solidifies to form a solidified layer. As shown in Figure 3, the application of capsule-type water glass in dual-slurry grouting is illustrated, showing the process of capsule dissolution / rupture and water glass mixing with cement slurry. Figure 4 shows the application diagram, which includes a sealing device 10, a borehole 20, a cement grout section 30, and a mixing section 40. Specifically, it includes: preparation: confirming the geological conditions of the coal and rock strata in the construction area, selecting suitable grouting equipment and materials, and preparing capsule-shaped water glass and cement grout; drilling operation: using a drilling rig to perform drilling operations at predetermined locations, ensuring that the diameter and depth of the borehole meet the design requirements; grouting operation: injecting capsule-shaped water glass and cement grout together into the borehole. The capsule-shaped water glass slowly dissolves or ruptures in the grouting section, releasing water glass and fully mixing with the cement grout; grout solidification: after mixing in the grouting section, the water glass and cement grout solidify to form a solidified layer.

[0065] Capsule release is controlled by at least one of the following factors: the thickness, composition, degree of cross-linking, and porosity of the shell material, as well as the pH and temperature of the grouting environment.

[0066] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0067] Example 1: This example provides a microcapsule-type water glass for dual-slurry grouting and its preparation method. The capsule-type water glass is prepared by a drop-casting method, specifically including the following steps: Preparing the water glass solution: Prepare a 40% concentration water glass solution; Preparing the capsule shell material: Select polylactic acid (PLA) as the shell material, dissolve PLA in dichloromethane to prepare a 5% PLA solution; Preparing the capsule by the drop-casting method: Drop the PLA solution into the water glass solution to form PLA-encapsulated water glass droplets; Controlling the capsule diameter to 1-2 mm and the wall thickness to 0.1-0.2 mm; Drying treatment: Drying at 40℃ for 24 hours to obtain the capsule-type water glass.

[0068] Example 2: This example provides a method for preparing microcapsule-type water glass for dual-slurry grouting. The capsule-type water glass prepared is used for dual-slurry grouting, specifically in coal seam reinforcement. The method includes: preparation: confirming the geological conditions of the coal seam in the construction area, selecting suitable grouting equipment and materials; preparing capsule-type water glass and cement slurry (water-cement ratio of 0.5:1); drilling operation: drilling a hole with a diameter of 100mm and a depth of 50m; according to Article 46, when probing for water at locations where the expected water pressure is greater than 0.1MPa, pre-solidifying the casing and installing a gate valve; the water-stop casing should undergo a pressure resistance test, and the pressure resistance value should not be less than 1.5 times the expected hydrostatic pressure value; grouting operation: mixing the prepared capsule-type water glass with cement slurry at a volume ratio of 1:4. The grout is injected into the borehole simultaneously; the grouting pressure is controlled at 2 MPa and the grouting speed at 30 L / min; during the grouting process, the grouting pressure and speed are adjusted according to the borehole depth and geological conditions to ensure that the capsule can smoothly reach the target grouting section; grout solidification: after the grout fills the borehole, the borehole opening is sealed; according to the designed release time of the capsule, the settling time is adjusted to allow the capsule to slowly dissolve at the target position, releasing water glass and mixing it thoroughly with the cement grout; the settling time can be adjusted according to the actual situation to ensure that the grout is fully solidified; the release of the capsule is controlled by at least one of the following factors: the thickness, composition, cross-linking degree, and porosity of the shell material, as well as the pH value and temperature of the grouting environment; specifically: the higher the cross-linking degree, the lower the porosity, the denser the capsule structure, the more hindered the water penetration, and the longer the degradation and release time.

[0069] Materials with higher water solubility have easier capsule dissolution in water, shorter degradation time, and faster release.

[0070] The thickness directly determines the length of the capsule wall's permeation path; the greater the thickness, the longer the degradation time.

[0071] Environmental factors such as pH (acidity accelerates the degradation of some biodegradable materials), temperature (high temperature accelerates the reaction), and ionic strength all have a significant impact on capsule degradation. Material performance screening and adjustment effects were observed using a typical engineering site environment as a benchmark: Seven days after grouting was completed, the formation of the consolidation layer was observed through core sampling and compressive strength testing.

[0072] The results show that the capsule-type water glass grouting method of the present invention improves the compressive strength of the solidified layer by 25% compared with the traditional two-liquid grouting method, and the uniformity of the solidified layer is significantly improved.

[0073] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0074] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0075] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A microcapsule-type water glass for dual-slurry grouting, characterized in that, It includes a water glass solution and a shell encapsulating the water glass solution; the shell is a biodegradable or soluble material that can slowly dissolve or rupture in a cement slurry environment to release the water glass.

2. The microcapsule-type water glass for dual-slurry grouting as described in claim 1, characterized in that, The outer shell material is selected from natural polymers, synthetic polymers, inorganic materials or mixtures thereof, including polylactic acid, polyvinyl alcohol, gelatin, sodium alginate, chitosan, starch, polyacrylate, silicon dioxide, and calcium carbonate.

3. The method for preparing microcapsule-type water glass for dual-slurry grouting as described in claim 2, characterized in that, Includes the following steps: Step 1, Preparation of water glass solution: Dissolve water glass in water to prepare a water glass solution of the required concentration; Step 2, Prepare the capsule shell: Prepare the shell material using physical or chemical methods to obtain hollow capsules; Step 3, Fill with water glass solution: Fill the hollow capsules with the prepared water glass solution; Step 4, Drying / Curing: Dry or cure the filled capsule-shaped water glass.

4. The method for preparing microcapsule-type water glass for dual-slurry grouting as described in claim 3, characterized in that, The physical methods include dripping, spray drying, complex coagulation, and solvent evaporation; the chemical methods include interfacial polymerization and in-situ polymerization.

5. The method for preparing microcapsule-type water glass for dual-slurry grouting as described in claim 4, characterized in that, Specifically, the following steps are included: Prepare a 40% concentration water glass solution; select polylactic acid as the shell material, dissolve polylactic acid in dichloromethane to prepare a 5% polylactic acid solution; Polylactic acid solution is dropped into water glass solution to form droplets of water glass encapsulated by polylactic acid; after drying at 40°C for 24 hours, capsule-shaped water glass is obtained.

6. The method for preparing microcapsule-type water glass for dual-slurry grouting as described in claim 5, characterized in that, The capsule diameter is controlled at 1-2 mm, and the wall thickness is 0.1-0.2 mm.

7. The microcapsule-type water glass prepared by the method for preparing microcapsule-type water glass for dual-slurry grouting as described in claim 4 is used for dual-slurry grouting, comprising injecting the capsule-type water glass and cement slurry together into the borehole, wherein the capsule-type water glass slowly dissolves or ruptures in the grouting hole section, releasing water glass, which is fully mixed with the cement slurry, and then solidifies to form a consolidation layer.

8. The application of the microcapsule-type water glass as described in claim 7 for dual-slurry grouting, comprising: Preparation: Confirm the geological conditions of coal and rock strata in the construction area, select grouting equipment and materials, and prepare capsule-type water glass and cement grout; Drilling operation: Use a drilling rig to drill holes at predetermined locations, ensuring that the diameter and depth of the holes meet the design requirements; Grouting operation: Inject capsule-shaped water glass and cement grout together into the drill hole. The capsule-shaped water glass slowly dissolves or ruptures in the grouting section, releasing the water glass and mixing it thoroughly with the cement grout; Grout curing: After the water glass and cement grout are mixed in the grouting section, they are cured to form a solidified layer.

9. The application of the microcapsule-type water glass as described in claim 8 for dual-slurry grouting specifically includes: Preparation: Confirm the geological conditions of the coal seam in the construction area, select grouting equipment and materials, and prepare capsule-shaped water glass and cement grout with a water-cement ratio of 0.5:

1. Drilling operation: Drill a hole with a diameter of 100mm and a depth of 50m. When probing for water at locations where the expected water pressure is greater than 0.1MPa, pre-solidify the casing and install gate valves. Conduct a pressure resistance test on the water-stop casing, and the pressure resistance value should not be less than 1.5 times the expected hydrostatic pressure. Grouting operation: Mix the prepared capsule-shaped water glass and cement grout at a volume ratio of 1:4 and inject them together into the borehole. Control the grouting pressure to... The grouting pressure was 2 MPa, and the grouting speed was 30 L / min. During the grouting process, the grouting pressure and speed were adjusted according to the drilling depth and geological conditions to ensure that the capsule could reach the target grouting section smoothly. Grout solidification: After the grout filled the borehole, the borehole opening was sealed. The settling time was adjusted according to the release time of the capsule to allow the capsule to slowly dissolve at the target position and release water glass to fully mix with the cement grout. The settling time was adjusted according to the actual situation to ensure that the grout was fully solidified. Effect observation: Seven days after the completion of grouting, the formation of the consolidation layer was observed by core sampling and compressive strength testing.

10. The application of the microcapsule-type water glass as described in claim 9 for dual-slurry grouting, wherein the release of the capsule is controlled by at least one of the following factors: the thickness, composition, degree of cross-linking, and porosity of the shell material, and the pH value and temperature of the grouting environment.

Images