Method for protecting buildings and structures through oxidation zone grouting under separation layer grouting filling

Abstract

The invention discloses a method for protecting a building by grouting an oxidation zone under separation layer grouting filling, which comprises the following steps of: determining parameters based on geological data and rock movement characteristics, and implementing overlying strata separation layer grouting; before the working face is pushed to the protection coal pillar, horizontal raft grouting drill holes are constructed in a preset area below the building structure, and grout is injected to form a raft; on the basis of bed separation grouting, grouting drill holes are constructed in a wind oxidation zone, and the grout proportion is dynamically adjusted for grouting according to the advancing position of a working face; based on the I-level damage standard of buildings and structures, the mining and injection collaboration is dynamically regulated and controlled in combination with ground surface deformation monitoring data. Through cooperation of the three grouting modes, the problem that settlement reduction and uneven deformation prevention cannot be achieved at the same time through single grouting is solved, close-range buildings and structures are effectively protected, coal pressing resources under the three conditions are released, and environmental protection and economical efficiency are achieved at the same time.

Description

Technical Field

[0001] This invention relates to the field of coal mine backfilling technology, specifically to a method for grouting and protecting structures in the oxidation zone under delamination grouting backfilling. Background Technology

[0002] The basic principle of overburden separation grouting is to inject high-pressure grout into the separation space, filling it with grout to support the overlying strata, block the transmission of mining activity, and thus control the movement of the overlying strata and reduce surface subsidence. The principle of wind-oxidized zone grouting is to inject grout into the wind-oxidized zone, filling the space within the zone to reduce surface subsidence. Both methods can reduce surface subsidence and are beneficial for protecting surface structures. When there are structures on the surface near the working face on the dip side, even with separation grouting, the structures will still experience uneven subsidence due to mining operations, leading to significant tilting and horizontal deformation and ultimately damage.

[0003] Among existing patents, CN201410313605.6 - A method for reinforcing and correcting building foundations using combined grouting, organically combining polyurethane grouting and silicate cement grouting. This involves drilling polyurethane grouting holes at the locations of greatest foundation settlement and injecting polyurethane reactive raw material grout, which undergoes a chemical reaction and expansion to reinforce and lift the foundation at those locations. CN201610509519.1 - A grouting reinforcement method for effectively reducing uneven settlement of building foundations, utilizing pressure grouting to reinforce both reinforced and general grouting zones. CN202210829056.2 - A composite filling method for shallow-buried, high-extraction goaf and delamination zones in coal mining. This method involves mining the coal face using conventional mining techniques while simultaneously filling the goaf areas requiring control to reduce surface subsidence. CN202310537458.X - A multi-stage grouting reinforcement process for newly excavated roadways traversing wind-oxidized goaf areas. This reinforcement process uses grouting slurries with different compositions, performs multiple grouting sessions, and achieves multi-stage reinforcement. CN202311100468.3 - A method for arch-bridge type grouting reinforcement of existing building foundations. Grouting holes are located on the surface of the building's raft slab; vertical drilling and grouting are performed based on some of the grouting holes to form multiple pier-type pile foundations, with each pier-type pile foundation spaced apart at the edge of the building's raft slab surface; a second vertical drilling and grouting is performed based on another portion of the grouting holes to form an arched foundation between the pier-type pile foundations. The aforementioned patents address the problem of uneven settlement of surface structures on one side of the working face by using one of the following methods: delamination grouting, foundation grouting, or structural raft slab. However, none of the patents specifically involve a method for protecting structures that combines three grouting methods—delamination grouting, wind oxidation zone grouting, and raft slab grouting under the structure—to reduce near-distance tilting and horizontal deformation on one side of the working face. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention provides a method for protecting structures by grouting in the oxidation zone under delamination grouting. This method integrates coal face mining, delamination grouting, and grouting in the wind oxidation zone, making dynamic adjustments to achieve coordinated mining and grouting. This ensures that the surface movement and deformation at the structure location are within the Class I failure standard for the structure, until the coal face safely pushes past the coal pillar protected by the structure.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for grouting and protecting structures in the oxide zone under delamination grouting, comprising the following steps: S1. Based on geological data, determine the relevant parameters of coal seam occurrence and mining. Combine the characteristics of rock movement and the development law of overlying delamination, set the key parameters of delamination grouting, construct delamination grouting boreholes in the coal mining face and implement grouting to block the transmission of mining space and reduce surface subsidence. S2. Before the working face advances to the protective coal pillar of the building, horizontal raft grouting boreholes are drilled in the predetermined area below the building along the dip direction of the working face. Grout is injected into the boreholes to form an integral raft structure, ensuring that the foundation of the building settles evenly. S3. Based on the overburden separation grouting, construct the wind oxidation zone grouting borehole on the side of the coal mining face close to the building structure. After the technical casing is lowered to the preset depth, grout is injected into the wind oxidation zone. The grouting slurry ratio and grouting process are dynamically adjusted according to the advancing position of the working face. S4. Based on the Class I failure standard for buildings and structures, monitor surface movement and deformation data, and make dynamic adjustments based on the overall mining progress of the working face and the effects of the two types of grouting, so that the surface movement and deformation are always within the Class I failure standard for buildings and structures until the working face pushes past the protective coal pillar.

[0006] Preferably, in S1, the parameters related to coal seam occurrence and mining include coal seam burial depth, mining area range, mining height and stratum distribution; rock movement characteristics are determined by at least one method among physical simulation, numerical simulation and theoretical analysis; key parameters for delamination grouting include grouting delamination layer position, delamination grouting borehole spacing and delamination grouting pressure.

[0007] Preferably, in S2, the range of the coal pillar protected by the building structure is determined according to the building structure's footprint, the thickness of the rock strata below the building structure, and the rock strata's movement angle; the thickness of the preset area is 30-50m, and is adjusted according to the thickness of the loose layer below the building structure; the number and spacing of the horizontal raft grouting boreholes are determined according to the range of the coal pillar protected and the length of the building structure.

[0008] Preferably, in S2, the grout is prepared from silicate cement and water, with a water-cement ratio of 1:1; the borehole pressure for raft foundation grouting is... ,

[0009] In the formula: —Raft foundation grouting pressure, MPa; —Depth of the raft grouting borehole from the ground surface to the grouting filling layer, in meters; —Comprehensive specific gravity of the strata above the raft foundation grouting filling layer, kN / m³ 3 ; —Specific gravity of grout used for raft foundation filling, kN / m³ 3 ; —Specific gravity pressure of the building structure, MPa.

[0010] Preferably, in step S3, the technical casing is lowered below the boundary between the Quaternary and Permian strata, and the grouting layer is located within the aeolian oxidation zone 4 to 6 meters below the boundary, with the depth adjusted according to the thickness of the aeolian oxidation zone.

[0011] Preferably, in S3, the number of grouting boreholes in the wind-oxidized zone is determined by the range of the protective coal pillar and the slurry diffusion radius, and the borehole spacing is determined based on the slurry diffusion range and the range of the protective coal pillar; the slurry diffusion radius... Calculate using the following formula: ; In the formula: — Grouting and filling pressure in the wind-oxidized zone, MPa; —Average thickness of coal seam, in meters; —Slurry diffusion coefficient, taken as 38~40; Distance between adjacent grouting holes satisfy: , The safety factor is set to 0.5.

[0012] Preferably, in S3, the process of dynamically adjusting the grout mix ratio includes: When the working face advances to the first grouting borehole in the wind oxidation zone, a slurry containing fly ash, water and polyurethane organic sealant is injected, wherein the polyurethane organic sealant accounts for 0.015 to 0.02% of the total mass of the fly ash slurry, and the water-ash ratio is 1:1. When the working face advances to the area between two adjacent grouting boreholes in the aeolian oxidation zone, a grout containing fly ash, silicate cement, and water glass is injected. The mass ratio of silicate cement to fly ash is 1:3, the water-cement ratio gradually changes from 1:1 to 0.8:1, and the proportion of water glass added is 5% to 10% of the sum of the mass of silicate cement and fly ash. After the working face has passed all the grouting boreholes in the aeolian oxidation zone, the content of silicate cement in the grout is increased, and its mass ratio with fly ash is adjusted from 1:3 to 1:2. The water-cement ratio is maintained at 0.8:1, and the proportion of water glass added is 5% to 10% of the sum of the mass of silicate cement and fly ash.

[0013] Preferably, the grouting pressure of the wind oxidation zone Calculate using the following formula: ; In the formula: — Grouting and filling pressure in the wind-oxidized zone, MPa; —Depth of the grouting borehole in the aeolian oxidation zone from the surface to the grouting filling layer, in meters; —Comprehensive specific gravity of the strata above the grouting and filling layer in the wind-oxidized zone, kN / m 3 ; —Specific gravity of the grout used for filling the wind-oxidized belt, kN / m 3 ; —The safety factor for grouting in the wind-oxidized zone is taken as 0.8 to 0.9; —Specific gravity pressure of the building structure, MPa.

[0014] Preferably, in S1, the grout for delamination grouting is prepared from fly ash and coal gangue, with a mass ratio of fly ash to coal gangue of 3:1, a water-cement ratio of 0.7:1 for the fly ash grout, and a water-cement ratio of 1:1 for the coal gangue grout.

[0015] Preferably, the Class I damage standard for buildings and structures is: horizontal deformation ≤ 2.0 mm / m, curvature ≤ 0.2 × 10⁻⁶. -3 m -1 Inclination ≤ 3.0 mm / m; dynamic adjustment includes increasing the grouting volume of delamination grouting and wind oxidation zone grouting when the surface movement and deformation tend to increase.

[0016] Compared with the prior art, the present invention provides a method for grouting and protecting structures in the oxide zone by delamination grouting, which has the following beneficial effects: (1) This application integrates three core technologies: overburden delamination grouting, raft slab grouting under buildings and structures, and wind oxidation zone grouting, to form a protection system that reduces deep settlement, stabilizes the foundation, and strengthens the surface. Among them, overburden delamination grouting blocks the transmission of mining activities from the source, wind oxidation zone grouting further enhances the settlement reduction effect, and raft slab grouting ensures uniform settlement of the foundation by forming an integral raft slab structure. The three technologies work together to completely solve the problem that a single grouting method cannot simultaneously reduce overall settlement and avoid local uneven deformation. This ensures that the surface movement and deformation at the building and structure location are strictly controlled within the Class I damage standard for buildings and structures, effectively avoiding structural damage such as tilting and cracking.

[0017] (2) By directional drilling of horizontal raft slab grouting holes along the dip direction of the working face, a continuous and complete raft slab structure is formed under the building, which significantly improves the integrity and bearing stability of the foundation, transforms the dispersed foundation stress into the overall stress, effectively offsets the uneven settlement stress caused by the mining of the coal face, and ensures that the building remains uniformly settled throughout the mining process, fundamentally solving the problem of structural damage caused by local settlement differences in nearby buildings.

[0018] (3) This application significantly reduces the range and extent of the impact of mining on the surface through the combined settling effect of delamination grouting and wind oxidation zone grouting, breaks the technical limitations of traditional “three-under” coal mining, and can safely and efficiently mine stagnant coal resources that could not be used due to the protection of surface buildings, and significantly improve the recovery rate and utilization efficiency of coal resources. Attached Figure Description

[0019] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention, but do not constitute a limitation thereof. In the drawings: Figure 1 Flowchart of a method for grouting and protecting structures in the oxide zone under delamination grouting; Figure 2 This is a schematic diagram of the delamination grouting filling layer in an embodiment of the present invention; Figure 3 This is a schematic diagram of the delamination grouting filling method in the embodiment; Figure 4 This example illustrates the relative positional relationship between the protective coal pillar under the structure and the working face. Figure 5 This is a schematic diagram of the grouting borehole arrangement for the raft foundation of the building in an embodiment of the present invention; Figure 6 This is a schematic cross-sectional view of the raft foundation grouting in an embodiment of the present invention; Figure 7 This is a schematic diagram of the grouting layer in the wind oxidation zone in an embodiment of the present invention; Figure 8 This is a schematic diagram of the grouting borehole layout in the wind oxidation zone according to an embodiment of the present invention; Figure 9 This is a schematic diagram of the working face advancing towards the grouting borehole Q1 in the wind-oxidized zone in an embodiment of the present invention; Figure 10 This is a schematic diagram of the working face advancing towards the grouting boreholes Q1 and Q2 in the wind oxidation zone in an embodiment of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0021] This embodiment proposes a method for grouting and protecting structures in the oxide zone through delamination grouting. Detailed steps are as follows: Figures 1-10 As shown: (1) Analyze the development pattern of the delamination and implement grouting for the overlying delamination. Based on relevant geological data, the coal seam depth, mining area, mining height, and stratigraphic distribution were determined. Rock movement characteristics were studied using a combination of physical simulation, numerical simulation, and theoretical analysis. Then, the development pattern of overlying strata delamination was analyzed to determine the grouting delamination layer and the spacing between grouting boreholes. l Based on grouting parameters such as grouting pressure, grouting separation grouting is implemented to form L1~L in the coal mining face. n Separation grouting borehole.

[0022] (2) Grouting of the raft foundation under the building structure On one side of the working face, there is a protective coal pillar within a range of C m for nearby structures. The value of C is determined based on the actual footprint of the structures, the thickness of the underlying strata, and the angle of strata movement. Before the working face advances to the protective coal pillar of the structures, raft grouting is carried out in the Am area below the structures. The value of A is 30-50 m, depending on the thickness of the loose layer below the structures. Along the dip direction of the working face, a row of horizontal raft grouting boreholes is drilled at a spacing of l1 on the side of the structures away from the working face. The number of raft grouting boreholes and the spacing l1 are determined based on the protective coal pillar within a range of C m below the structures and the length D m of the structures. The value of D is determined based on the actual footprint of the structures. A grout prepared from silicate cement and water is injected into the raft grouting boreholes below the structures, with a water-cement ratio of 1:1.

[0023] Grouting pressure (pressure at the borehole opening for raft grouting): ; In the formula: —Raft foundation grouting pressure, MPa; —Depth of the raft grouting borehole from the ground surface to the grouting filling layer, in meters; —Comprehensive specific gravity of the strata above the raft foundation grouting filling layer, kN / m³ 3 ; —Specific gravity of grout used for raft foundation filling, kN / m³ 3 ; —Specific gravity pressure of the building structure, MPa.

[0024] (3) Grouting of the wind oxidation zone Based on the implementation of delamination grouting and backfilling mining, grouting of the aeolian oxidation zone is carried out. The casing of the aeolian oxidation zone grouting drilling technology is lowered to below the boundary between the Quaternary and Permian strata, and grouting is carried out within the aeolian oxidation zone. A row of aeolian oxidation zone grouting boreholes Q1~Q is constructed near buildings and structures within the coal mining face area. n The number of grouting boreholes in the wind-oxidation zone is determined by a combination of the range of the coal pillar protected by the structure and the grout diffusion radius. The spacing between the grouting boreholes in the wind-oxidation zone... l 2. The grouting pressure in the wind-oxidizing zone is determined comprehensively based on factors such as the slurry diffusion range and the range of coal pillars protected by buildings and structures. P 2. The determination is based on a combination of the grouting borehole depth, the specific gravity of the formation, and the specific gravity of the grout.

[0025] 1) Grouting layer Grouting was performed in the wind-oxidized zone, and the drilling casing was lowered to below the boundary between the Quaternary and Permian strata. E / O Grouting is carried out within the Ym wind oxidation zone below the boundary. The Y value can be taken as 4~6m depending on the thickness of the wind oxidation zone. 2) Grouting pressure Grouting pressure in wind-oxidized zone (grouting borehole pressure in wind-oxidized zone): ; In the formula: — Grouting and filling pressure in the wind-oxidized zone, MPa; —Depth of the grouting borehole in the aeolian oxidation zone from the surface to the grouting filling layer, in meters; —Comprehensive specific gravity of the strata above the grouting and filling layer in the wind-oxidized zone, kN / m 3 ; —Specific gravity of the grout used for filling the wind-oxidized belt, kN / m 3 ; —The safety factor for grouting in the wind-oxidized zone is taken as 0.8~0.9; —Specific gravity pressure of the building structure, MPa.

[0026] 3) Laying out grouting boreholes Based on the implementation of delamination grouting and backfilling mining, a row of ventilation oxidation zone grouting boreholes Q1~Q were constructed near buildings and structures within the coal mining face area. n .

[0027] Slurry diffusion radius: ; In the formula: — Grouting and filling pressure in the wind-oxidized zone, MPa; —Average thickness of coal seam, in meters; —The slurry diffusion coefficient is taken as 38~40.

[0028] Drilling spacing: ; In the formula: —Distance between adjacent grouting holes, in meters; —Safety factor, set to 0.5; —Slurry diffusion radius, m.

[0029] 4) Implementation steps Taking the grouting process of the wind-oxidized zone as an example, the grouting drilling of hole Q1 in the wind-oxidized zone is as follows: ① When the coal mining face advances to the first grouting borehole Q1 in the grouting area of ​​the wind oxidation zone, inject a slurry prepared from fly ash, water, and polyurethane organic sealant into the grouting borehole Q1. The water-ash ratio is 1:1, and the polyurethane organic sealant accounts for 0.015~0.02% of the total mass of the fly ash slurry. ② When the working face advances to the area between the grouting boreholes Q1 and Q2 in the wind-oxidation zone, a grout prepared from fly ash, silicate cement, and water glass is injected. The grout is gradually made up of pure fly ash with silicate cement added gradually (the mass ratio of silicate cement to fly ash is 1:3). The water-cement ratio is gradually changed from 1:1 to 0.8:1. The proportion of water glass added is 5% to 10% of the sum of the mass of silicate cement and fly ash. ③ When the working face pushes past the grouting drilling hole Q in the oxidation zone n Subsequently, the content of silicate cement in the slurry was increased, the mass ratio of silicate cement to fly ash was adjusted from 1:3 to 1:2, the water-cement ratio was 0.8:1, and the proportion of water glass added was 5% to 10% of the sum of the mass of silicate cement and fly ash; ④ Continue grouting in hole Q1 of the wind oxidation zone until it can no longer be injected, then stop grouting in hole Q1 of the wind oxidation zone; ⑤ Grouting drilling in the wind oxidation zone Q2~Q n Grouting of the wind oxidation zone was carried out according to the above procedure.

[0030] like Figure 8 As shown, while the working face advances to the grouting borehole Q1 in the aeolian oxidation zone, the coal mining face also advances to the separation grouting borehole L7. Grouting and filling begins in the separation grouting borehole L7, injecting a slurry prepared from fly ash and coal gangue. The mass ratio of fly ash to coal gangue is 3:1, the water-ash ratio of the fly ash slurry is 0.7:1, and the water-ash ratio of the coal gangue slurry is 1:1. Separation grouting boreholes L1~L... nAll use the same grouting materials and grout ratio as L7.

[0031] (4) Standard for Class I damage to buildings and structures: horizontal deformation ≤ 2.0 mm / m, curvature ≤ 0.2 × 10 -3 m -1 The inclination is ≤3.0mm / m. The Class I damage standard for buildings and structures is used as the criterion for judging the degree of protection of buildings and structures. Based on the daily monitoring data of surface movement and deformation at the building / structure location and the comparison with the criterion, dynamic adjustments are made to the mining operations, delamination grouting, and grouting in the wind-oxidized zone to achieve coordinated mining and grouting. When the movement and deformation show a tendency to increase, the grouting volume of the wind-oxidized zone grouting and delamination grouting is appropriately increased to keep the surface movement and deformation at the building / structure location within the Class I damage standard for buildings and structures, until the working face safely pushes past the protective coal pillar of the building / structure.

[0032] In the description of this invention, the terms "first," "second," "another," and "yet another" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of embodiments of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0033] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0034] 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 grouting and protecting structures in the oxide zone by delamination grouting, characterized in that, Includes the following steps: S1. Based on geological data, determine the relevant parameters of coal seam occurrence and mining. Combine the characteristics of rock movement and the development law of overlying delamination, set the key parameters of delamination grouting, construct delamination grouting boreholes in the coal mining face and implement grouting to block the transmission of mining space and reduce surface subsidence. S2. Before the working face advances to the protective coal pillar of the building, horizontal raft grouting boreholes are drilled in the predetermined area below the building along the dip direction of the working face. Grout is injected into the boreholes to form an integral raft structure, ensuring that the foundation of the building settles evenly. S3. Based on the overburden separation grouting, construct the wind oxidation zone grouting borehole on the side of the coal mining face close to the building structure. After the technical casing is lowered to the preset depth, grout is injected into the wind oxidation zone. The grouting slurry ratio and grouting process are dynamically adjusted according to the advancing position of the working face. S4. Based on the Class I failure standard for buildings and structures, monitor surface movement and deformation data, and make dynamic adjustments based on the overall mining progress of the working face and the effects of the two types of grouting, so that the surface movement and deformation are always within the Class I failure standard for buildings and structures until the working face pushes past the protective coal pillar.

2. The method for grouting and protecting structures in the oxide zone by delamination grouting according to claim 1, characterized in that, In S1, parameters related to coal seam occurrence and mining include coal seam burial depth, mining area range, mining height, and stratum distribution; rock movement characteristics are determined by at least one of physical simulation, numerical simulation, and theoretical analysis; key parameters for delamination grouting include grouting delamination layer position, delamination grouting borehole spacing, and delamination grouting pressure.

3. The method for grouting and protecting structures in the oxide zone by delamination grouting according to claim 2, characterized in that, In S2, the range of the coal pillar protected by the building structure is determined based on the building structure's footprint, the thickness of the rock strata below the building structure, and the rock strata's movement angle; the thickness of the preset area is 30-50m, and is adjusted according to the thickness of the loose layer below the building structure; the number and spacing of horizontal raft grouting boreholes are determined based on the range of the coal pillar protected and the length of the building structure.

4. The method for grouting and protecting structures in the oxide zone by delamination grouting according to claim 3, characterized in that, In S2, the grout is prepared from silicate cement and water, with a water-cement ratio of 1:1; the borehole pressure for raft foundation grouting is... , ； In the formula: —Raft foundation grouting pressure, MPa; —Depth of the raft grouting borehole from the ground surface to the grouting filling layer, in meters; —Comprehensive specific gravity of the strata above the raft foundation grouting filling layer, kN / m³ 3 ; —Specific gravity of grout used for raft foundation filling, kN / m³ 3 ; —Specific gravity pressure of the building structure, MPa.

5. The method for grouting and protecting structures in the oxide zone by delamination grouting according to claim 4, characterized in that, In S3, the technical casing is lowered to below the boundary between the Quaternary and Permian strata, and the grouting layer is located 4 to 6 meters below the boundary in the aeolian oxidation zone, and this depth is adjusted according to the thickness of the aeolian oxidation zone.

6. The method for grouting and protecting structures in the oxide zone by delamination grouting according to claim 5, characterized in that, In S3, the number of grouting boreholes in the wind-oxidized zone is determined by the range of the protective coal pillar and the slurry diffusion radius, while the borehole spacing is determined based on the slurry diffusion range and the range of the protective coal pillar; the slurry diffusion radius... Calculate using the following formula: ； In the formula: — Grouting and filling pressure in the wind-oxidized zone, MPa; —Average thickness of coal seam, in meters; —Slurry diffusion coefficient, taken as 38~40; Distance between adjacent grouting holes satisfy: , The safety factor is set to 0.

5.

7. The method for grouting and protecting structures in the oxide zone by delamination grouting according to claim 6, characterized in that, In S3, the process of dynamically adjusting the grout mix ratio includes: When the working face advances to the first grouting borehole in the wind oxidation zone, a slurry containing fly ash, water and polyurethane organic sealant is injected, wherein the polyurethane organic sealant accounts for 0.015 to 0.02% of the total mass of the fly ash slurry, and the water-ash ratio is 1:

1. When the working face advances to the area between two adjacent grouting boreholes in the aeolian oxidation zone, a grout containing fly ash, silicate cement, and water glass is injected. The mass ratio of silicate cement to fly ash is 1:3, the water-cement ratio gradually changes from 1:1 to 0.8:1, and the proportion of water glass added is 5% to 10% of the sum of the mass of silicate cement and fly ash. After the working face has passed all the grouting boreholes in the aeolian oxidation zone, the content of silicate cement in the grout is increased, and its mass ratio with fly ash is adjusted from 1:3 to 1:

2. The water-cement ratio is maintained at 0.8:1, and the proportion of water glass added is 5% to 10% of the sum of the mass of silicate cement and fly ash.

8. The method for grouting and protecting structures in the oxide zone by delamination grouting according to claim 7, characterized in that, Grouting pressure in wind oxidation zone Calculate using the following formula: ； In the formula: — Grouting and filling pressure in the wind-oxidized zone, MPa; —Depth of the grouting borehole in the aeolian oxidation zone from the surface to the grouting filling layer, in meters; —Comprehensive specific gravity of the strata above the grouting and filling layer in the wind-oxidized zone, kN / m 3 ; —Specific gravity of the grout used for filling the wind-oxidized belt, kN / m 3 ; —The safety factor for grouting in the wind-oxidized zone is taken as 0.8 to 0.9; —Specific gravity pressure of the building structure, MPa.

9. A method for grouting and protecting structures in the oxide zone by delamination grouting according to claim 1, characterized in that, In S1, the grout for delamination grouting is prepared from fly ash and coal gangue, with a mass ratio of fly ash to coal gangue of 3:1, a water-cement ratio of 0.7:1 for fly ash grout, and a water-cement ratio of 1:1 for coal gangue grout.

10. A method for grouting and protecting structures in the oxide zone by delamination grouting according to claim 1, characterized in that, The Class I failure standard for buildings and structures is: horizontal deformation ≤ 2.0 mm / m, curvature ≤ 0.2 × 10⁻⁶. -3 m -1 Inclination ≤ 3.0 mm / m; dynamic adjustment includes increasing the grouting volume of delamination grouting and wind oxidation zone grouting when the surface movement and deformation tend to increase.

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