A method for reconstructing water-proof soil layer by rotary grouting in coal mining

Abstract

The invention discloses a method for reconstructing a water-proof soil layer in coal mining by rotary grouting, which relates to the field of geology and mining engineering technology, including: obtaining the thickness of the water-proof soil layer according to a borehole column chart before mining of a coal mining face; obtaining the periodic pressure step and the initial pressure step by observing the mine pressure during the coal mining stage; implementing multiple detection boreholes on the ground of the coal mining area after the coal mining is completed at the coal mining face; obtaining the average width of the internal surface cracks and the average width of the boundary surface cracks at the coal mining face by observing the ground after the coal mining collapse is stable; implementing an internal rotary grouting drilling group inside the coal mining face; and implementing a boundary rotary grouting drilling group at the boundary of the coal mining face. The method of the invention is simple and easy to implement, and has high implementation efficiency, and the anti-seepage effect and reconstruction effect achieved are better.

Description

Technical Field

[0001] The invention relates to the technical field of geology and mining engineering, and in particular to a method for reconstructing a water-proof soil layer through rotary grouting in coal mining. Background Art

[0002] The ecological environment in western my country is fragile. Coal mining causes the groundwater level to drop, which has an impact on the ecological environment. Therefore, the impermeable soil layer beneath the ecological groundwater urgently needs to be reconstructed. The traditional impermeable soil layer reconstruction has the following problems:

[0003] (1) The traditional hydraulic grouting method for the reconstruction of water-tight soil layers has a limited injection volume and insufficient diffusion range for the fractured water-tight soil layers.

[0004] (2) Grouting reconstruction of fissured soil layers. After the fissures are filled and reinforced, an interface between the slurry and the soil layer exists. The interface is the main path for seepage, which means that the reconstruction effect is limited.

[0005] (3) The mine pressure from coal mining is used to reconstruct the impermeable soil layer. However, due to the tensile stress of the surface, the effect of the mine pressure in the shallow part is limited. In addition, this process lasts too long and the reconstruction efficiency is insufficient. Summary of the invention

[0006] The purpose of the present invention is to provide a method for reconstructing a water-proof soil layer in coal mining by rotary grouting, which can improve the efficiency and effect of reconstructing the water-proof soil layer in coal mining.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] A method for regenerating a water-proof soil layer during coal mining by rotary grouting, comprising:

[0009] Before mining at the coal face, the thickness of the impermeable soil layer is obtained according to the borehole histogram;

[0010] In the coal mining stage, the periodic pressure step and the initial pressure step are obtained through mine pressure observation;

[0011] After the coal mining is completed at the coal mining face, multiple detection boreholes are drilled on the ground of the coal mining area; and the average thickness of the internal crushed swelling water-proof soil layer of the coal mining face and the average thickness of the boundary crushed swelling water-proof soil layer of the coal mining face are obtained according to the detection boreholes; the terminal hole position of each detection borehole is located at the bottom plate of the coal seam;

[0012] After the coal mining subsidence is stabilized, the average width of the internal surface cracks and the average width of the boundary surface cracks of the coal mining working face are obtained through ground observation;

[0013] Implement an internal rotary jet drilling group inside the coal mining face; the final hole layer of the internal rotary jet drilling group is the bottom plate of the water-proof soil layer, and multiple internal rotary jet drilling holes of the internal rotary jet drilling group are distributed along the periodic pressure line; the basic parameters of each internal rotary jet drilling hole are determined according to the thickness of the water-proof soil layer, the average thickness of the internal crushing and swelling water-proof soil layer and the average width of the internal surface cracks;

[0014] A boundary rotary jet drilling group is implemented at the boundary of the coal mining working face; the final hole layer of the boundary rotary jet drilling group is the bottom plate of the water-impermeable soil layer, and the multiple boundary rotary jet drilling holes of the boundary rotary jet drilling group are distributed along the boundary line; the basic parameters of each boundary rotary jet drilling hole are determined according to the thickness of the water-impermeable soil layer, the average thickness of the boundary crushing water-impermeable soil layer and the average width of the boundary surface cracks.

[0015] Optionally, after coal mining is completed at the coal mining face, at least six of the detection drill holes are implemented on the ground of the coal mining area; wherein, at least three of the detection drill holes are arranged within the range of one periodic pressure step distance from the center position of the coal mining face; at least three of the detection drill holes are arranged within the coal mining face and within the range of one initial pressure step distance from the opening of the cutting eye.

[0016] Optionally, the components of the jet slurry of the internal jet grouting holes and the boundary jet grouting holes include glutinous rice paste, guar gum, clay, Bacillus pasteurianus powder, bacterial liquid binder and water.

[0017] Optionally, the number of live bacteria contained in each gram of the Bacillus pasteurianus powder is greater than 100 million; and the bacterial liquid binder is composed of urea and calcium chloride in a ratio of 1:1.

[0018] Optionally, in the rotary jet slurry for the internal rotary jet drilling, glutinous rice slurry accounts for 10 to 20 parts, guar gum accounts for 10 to 20 parts, clay accounts for 100 to 200 parts, Bacillus pasteurianus powder accounts for 20 to 60 parts, bacterial liquid binder accounts for 20 to 60 parts, and water accounts for 160 to 360 parts.

[0019] Optionally, in the jet slurry for the boundary jet drilling, glutinous rice slurry accounts for 20-30 parts, guar gum accounts for 10-30 parts, clay accounts for 100-200 parts, Bacillus pasteurianus powder accounts for 50-100, bacterial liquid binder accounts for 50-100, and water accounts for 230-460 parts.

[0020] Optionally, the basic parameters of the internal jet grouting drilling include hole diameter, jet grouting lifting speed and total amount of jet grouting slurry;

[0021] The diameter of the internal jet-jet drill hole is 1.0 to 1.2 times the average width of the internal surface cracks;

[0022] The jet grouting lifting speed of the internal jet grouting drilling hole is: v1 = k11 ×v; where v is the normal lifting speed; k 11 is the correction coefficient of the jet grouting lifting speed of the internal jet grouting drilling hole, when (T1-T)÷T is less than 0.01, it is taken as 0.8, when (T1-T)÷T is greater than or equal to 0.01, it is taken as 0.6; T1 represents the average thickness of the internal crushing and swelling water-proof soil layer; T represents the thickness of the water-proof soil layer;

[0023] The total amount of the jet slurry in the internal jet drilling hole is: Q1 = k 12 ×(T1÷v1×Q); where k 12 is the correction coefficient of grouting volume of internal jet-jet drilling; Q is the normal grouting speed;

[0024] Optionally, the basic parameters of the boundary jet grouting drilling include the aperture of the boundary jet grouting drilling, the jet grouting lifting speed and the total amount of the jet grouting slurry;

[0025] The aperture of the boundary jet-jet drilling hole is 1.0 to 1.2 times the average width of the boundary surface cracks;

[0026] The jet grouting lifting speed of the boundary jet grouting drilling hole is: v2 = k 21 ×v; where k 21 is the correction coefficient of the jet grouting lifting speed of the boundary jet grouting drilling hole, when (T2-T)÷T is less than 0.01, it is taken as 0.8, when (T2-T)÷T is greater than or equal to 0.01, it is taken as 0.6; T2 represents the average thickness of the boundary crushing and swelling water-proof soil layer;

[0027] The total amount of jet slurry in the boundary jet drilling hole is: Q2 = k 22 ×(T2÷v2×Q); where k 22 It is the correction factor of grouting volume for boundary jet jet drilling.

[0028] Optionally, the basic parameters of the internal jet-jet drilling holes and the boundary jet-jet drilling holes also include the spacing between adjacent drilling holes and the jet pressure;

[0029] The spacing between adjacent internal jet-jet holes is 10 to 30 meters.

[0030] The injection pressure of the internal jet grouting drilling hole is: P1=P+ΔP1; wherein P is the normal grouting pressure; ΔP1 is the average additional stress inside the coal mining working face;

[0031] The spacing between adjacent boreholes of the boundary jet-jet drilling holes is 20 to 50 meters;

[0032] The jet pressure of the inner boundary rotary jet drilling hole is: P2=P+ΔP2, wherein ΔP2 is the average additional stress at the boundary of the coal mining working face.

[0033] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0034] The invention discloses a method for reconstructing a water-proof soil layer in coal mining by rotary grouting, and relates to the field of geology and mining technology, including: obtaining the thickness of the water-proof soil layer according to a borehole columnar diagram before mining of a coal mining face; obtaining the periodic pressure step and the initial pressure step by observing the mine pressure during the coal mining stage; implementing multiple detection boreholes on the ground of a coal mining area after coal mining is completed at the coal mining face; obtaining the average width of the internal surface cracks and the average width of the boundary surface cracks of the coal mining face by observing the ground after the coal mining collapse is stable; implementing an internal rotary grouting drilling group inside the coal mining face; implementing a boundary rotary grouting drilling group at the boundary of the coal mining face, and determining the basic parameters of the internal rotary grouting drilling and the boundary rotary grouting drilling according to the detected relevant parameters, so that the mixing amount and mixing speed of the slurry are more in line with the law of rock movement in the mine, and the reconstruction effect is better. Therefore, the method of the invention is simple and easy to implement, and has high implementation efficiency, and the achieved anti-seepage effect is better and the reconstruction effect is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0036] Figure 1 A flow chart of a method for rotary grouting reconstruction of water-proof soil layers in coal mining provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] The purpose of the present invention is to provide a method for reconstructing a water-proof soil layer in coal mining by rotary grouting, which can improve the efficiency and effect of reconstructing the water-proof soil layer in coal mining.

[0039] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] Example 1

[0041] like Figure 1As shown, this embodiment provides a method for regenerating a water-proof soil layer by rotary grouting in coal mining, comprising:

[0042] S1: Before mining the coal face, the thickness T of the impermeable soil layer is obtained according to the borehole histogram.

[0043] S2: During the coal mining stage, the periodic pressure step Z and the initial pressure step C are obtained through mine pressure observation.

[0044] S3: After the coal mining is completed at the coal mining face, a plurality of detection boreholes are drilled on the ground of the coal mining area; and the average thickness of the internal expansive water-proof soil layer of the coal mining face and the average thickness T1 of the boundary expansive water-proof soil layer of the coal mining face are obtained based on the detection boreholes; the final hole position of each detection borehole is located at the bottom plate T2 of the coal seam.

[0045] After the coal mining is completed at the coal mining face, at least six detection holes can be drilled on the ground of the coal mining area. The detection hole values ​​are adjusted according to actual needs and have no limiting effect.

[0046] Among them, at least three (at least half of the number) of the detection boreholes are arranged within the range of one cycle pressure step distance from the center position of the coal mining working face; the detection boreholes are used to obtain the average thickness T1 of the internal swelling and impermeable soil layer of the coal mining working face.

[0047] At least three detection boreholes are arranged within the coal mining face and within a range C of the first pressure step distance from the opening of the cutting hole. The detection boreholes obtain the average thickness T2 of the crushed and water-proof soil layer at the boundary of the coal mining face.

[0048] S4: After the coal mining subsidence is stabilized, the average width D1 of the internal surface cracks and the average width D2 of the boundary surface cracks of the coal mining working face are obtained through ground observation.

[0049] S5: Implement internal jet jet drilling group inside the coal mining face.

[0050] Among them, the final hole layer of the internal rotary jet drilling group is the bottom plate of the water-impermeable soil layer, and the multiple internal rotary jet drilling holes of the internal rotary jet drilling group are distributed along a periodic pressure line; the basic parameters of each internal rotary jet drilling hole are determined according to the thickness of the water-impermeable soil layer, the average thickness of the internal crushing water-impermeable soil layer and the average width of the internal surface cracks.

[0051] The basic parameters of each internal jet jet drilling include:

[0052] The hole diameter of the internal jet-jet drilling hole is 1.0 to 1.2 times of D1.

[0053] The jet lifting speed of the internal jet drilling hole: v1 = k 11×v; where v is the normal lifting speed, which is 0.2-0.25m / min; k 11 It is the correction coefficient of the internal jet grouting drilling and jet grouting lifting speed. When (T1-T)÷T is less than 0.01, it is 0.8. When (T1-T)÷T is greater than or equal to 0.01, it is 0.6. T represents the thickness of the impermeable soil layer.

[0054] The total amount of jet grout in a single internal jet drilling hole: Q1 = k 12 ×(T1÷v1×Q); where k 12 The correction coefficient for the grouting volume of internal jet grouting holes is taken as 1.1-1.2, and Q is the normal grouting rate, which is taken as 80-100L / min.

[0055] The distance between adjacent internal jet-jet drilling holes is 10 to 30 meters.

[0056] The injection pressure of the internal rotary jet drilling hole is: P1=P+ΔP1; wherein P is the normal shotcrete pressure, which is 20-25MPa; ΔP1 is the average additional stress inside the coal mining working face, which is obtained through well-known numerical simulation or physical simulation experiments, where it is a positive number when loaded and a negative number when unloaded.

[0057] As an optional embodiment, the composition of the jet slurry for internal jet drilling includes glutinous rice slurry, guar gum, clay, Bacillus pasteurianus powder, bacterial liquid binder and water. Among them, each gram of Bacillus pasteurianus powder contains more than 100 million live bacteria, and the bacterial liquid binder is composed of urea and calcium chloride in a ratio of 1:1. The mass composition of the internal jet slurry is 10 to 20 parts of glutinous rice slurry, 10 to 20 parts of guar gum, 100 to 200 parts of clay, 20 to 60 parts of Bacillus pasteurianus powder, 20 to 60 parts of bacterial liquid binder, and 160 to 360 parts of water. The proportion of each component in the jet slurry for internal jet drilling is determined within the corresponding range as needed, and any possible proportion within the range of proportions given in this application is within the protection scope of this application.

[0058] S6: Implement boundary jet grouting drilling group at the boundary of coal mining face. The boundary of coal mining face includes opening eye, closing line and two lanes.

[0059] Among them, the final hole layer of the boundary rotary jet drilling group is the bottom plate of the water-impermeable soil layer, and the multiple boundary rotary jet drilling holes of the boundary rotary jet drilling group are distributed along the boundary line; the basic parameters of each boundary rotary jet drilling hole are determined according to the thickness of the water-impermeable soil layer, the average thickness of the boundary crushing water-impermeable soil layer and the average width of the boundary surface cracks.

[0060] The basic parameters of the boundary jet drilling include:

[0061] The aperture of the boundary jet-jet drilling hole is 1.0 to 1.2 times of D2.

[0062] The jet grouting lifting speed v2 of the boundary jet grouting drilling hole is k 21 ×v; where v is the normal lifting speed, which is 0.2-0.25m / min; k 21 It is the correction coefficient of boundary jet grouting drilling lifting speed. When (T2-T)÷T is less than 0.01, it is taken as 0.8. When (T2-T)÷T is greater than or equal to 0.01, it is taken as 0.6.

[0063] The total amount of jet slurry in a single boundary jet drilling hole is Q2 = k 22 ×(T2÷v2×Q); where k 22 The correction coefficient for the grouting volume of boundary jet grouting holes is taken as 1.3-1.6, and Q is the normal grouting rate, which is taken as 80-100L / min.

[0064] The distance between adjacent boreholes of boundary jet jet drilling is 20 to 50 meters.

[0065] The injection pressure of the boundary rotary jet drilling hole P2=P+ΔP2; wherein P is the normal grouting pressure, which is 20-25MPa; ΔP2 is the average additional stress at the boundary of the coal mining working face, which is obtained through well-known numerical simulation or physical simulation experiments, wherein it is a positive number when loaded and a negative number when unloaded.

[0066] The specific values ​​of the basic parameters of the boundary jet grouting drilling holes and the basic parameters of the internal jet grouting drilling holes are adjusted according to actual needs. The jet grouting parameters are different in different coal mining overburden damage areas.

[0067] As an optional embodiment, the jet slurry for boundary jet drilling includes glutinous rice slurry, guar gum, clay, Bacillus pasteurianus powder, bacterial liquid binder and water. Among them, each gram of Bacillus pasteurianus powder contains more than 100 million live bacteria, and the bacterial liquid binder is composed of urea and calcium chloride in a ratio of 1:1. In the jet slurry for boundary jet drilling, glutinous rice slurry accounts for 20 to 30 parts, guar gum accounts for 10 to 30 parts, clay accounts for 100 to 200 parts, Bacillus pasteurianus powder accounts for 50 to 100, bacterial liquid binder accounts for 50 to 100, and water accounts for 230 to 460 parts. The proportion of each component in the jet slurry for boundary jet drilling is determined within the corresponding range as needed, and any possible proportion within the range of proportions given in this application is within the protection scope of this application.

[0068] The operating principle of the method provided in this embodiment is:

[0069] Coal mining causes the destruction of the impermeable soil layer and forms a fissured soil body. Traditional mining to reconstruct the impermeable soil layer generally involves pressing slurry into the fissures under high pressure. Since the impermeable soil layer is naturally water-proof, the fissures exposed by the borehole are easy to seal, but the fissures between the boreholes are difficult to reach under high pressure. In addition, the traditional grouting method is to fill the fissures, and the filled fissures form an interface with the slurry filling, which is prone to seepage, that is, the sealing effect is poor. In order to solve this problem, the present application is innovative in the following two aspects. First, rotary jet grouting fully mixes the impermeable soil layer with the slurry, does not form an obvious interface, and has better impermeability. In order to achieve this effect, different rotary jet parameters are used for different coal mining overburden damage areas, so that the mixing amount and mixing speed of the slurry are more in line with the law of rock movement in the mine. Second, rotary grouting breaks through the grouting distance of drilling and pressing. In particular, the use of microbial solidification materials and polysaccharide cementing materials has a larger diffusion range than cement and is more suitable for rotary grouting diffusion. In particular, microbial solidification materials can pass through relatively intact loess pores. In addition, polysaccharide cementing materials also provide a breeding basis for the continuous action of microorganisms.

[0070] Compared with the prior art, the present invention has the following beneficial effects:

[0071] 1) Grouting drilling requires less drilling than hydraulic grouting and is simpler and easier to implement.

[0072] 2) The efficiency is higher through the rapid solidification of polysaccharide structure and subsequent continuous solidification of microbial mineralization reinforcement.

[0073] 3) No chemical additives are used on a large scale, which is more environmentally friendly.

[0074] 4) Through high-pressure mixing, the fissured soil layer and the cementing liquid are fully mixed to form an interface, which has better anti-seepage effect and better reconstruction effect.

[0075] Example 2

[0076] This embodiment is an application example of the method for reconstructing the water-proof soil layer in coal mining by rotary grouting according to Embodiment 1.

[0077] A coal mine is mining No. 2 coal seam. The thickness of the impermeable soil layer overlying the coal seam is generally large. The water-conducting fracture zone generated by the No. 2 coal seam develops to the middle of the impermeable soil layer, but the loose layer groundwater on the remaining impermeable soil layer still seeps through the impermeable soil layer. Due to the decline in the ecological water level, the ground ecology has generally degraded. In order to protect the ecological water level, the impermeable soil layer was reinforced by rotary jet grouting. The specific steps are as follows:

[0078] Step 1: Before mining the coal face, the thickness of the impermeable soil layer T = 74 meters is obtained through the drilling column chart.

[0079] Step 2: During the coal mining stage, the periodic pressure step Z = 8.3 meters and the initial pressure step C = 14.4 meters are obtained through mine pressure observation.

[0080] Step 3: After the coal mining is completed at the coal mining face, 6 detection boreholes are implemented on the ground, and the final hole of the detection borehole is located at the bottom of the coal seam. Among them, 3 detection boreholes are within a periodic pressure step Z = 8.3 meters from the center of the coal mining face (the distances are 1.4 meters, 3.3 meters and 6.9 meters respectively), and the detection boreholes obtain the average thickness of the crushed and water-proof soil layer inside the coal mining face T1 = 77.8 meters. The 3 detection boreholes are within the coal mining face and within a first pressure step C = 14.4 meters from the opening of the cut (the distances are 3.2 meters, 4.4 meters and 9.3 meters respectively), and the detection boreholes obtain the average thickness of the crushed and water-proof soil layer at the boundary of the coal mining face T2 = 79.2 meters.

[0081] Step 4: After the coal mining subsidence is stabilized, the average width of the surface cracks inside and at the boundary of the coal mining face is obtained through ground observation D1 = 0.15 m and D2 = 0.38 m.

[0082] Step 5: Implement an internal jet grouting drilling group inside the coal mining face. The internal jet grouting drilling group drills at each periodic pressure point on the ground, and the final hole layer of the internal jet grouting drilling group is the bottom plate of the water-proof soil layer. The internal jet grouting drilling hole diameter is 1.0 times D1, that is, 0.15 meters. The internal jet grouting drilling group is distributed along the periodic pressure line, and the distance between adjacent boreholes is 20 meters. The jet grouting lifting speed v1 of the internal jet grouting drilling hole is k 11 ×v=0.6×0.2=0.12m / min, where v is the normal lifting speed, which is 0.2m / min; k 11 Q1 is the internal jet grouting lifting speed correction coefficient. Since (T1-T)÷T=(77.8-74)÷74=0.05, it is taken as 0.6 when it is greater than 0.01. The total amount of jet grout in a single internal jet grouting hole is Q1=k 12 ×(T1÷v1×Q)=1.2×(77.8÷0.12×100)=64832.13L=64.83213m 3 , where k 12 The correction coefficient for the grouting volume of the internal jet-jet drilling hole is 1.2, Q is the normal grouting rate, which is 100L / min. The injection pressure of the internal jet-jet drilling hole is P1=P+ΔP1=25+0.5=25.5MPa, where P is the normal grouting pressure, which is 25MPa; ΔP1 is the average additional stress inside the coal mining face, which is obtained through known numerical simulation or physical simulation experiments and is 0.5MPa.

[0083] The internal rotary spraying slurry is composed of glutinous rice paste, guar gum, clay, Bacillus pasteurianus powder, bacterial liquid binder and water, of which each gram of Bacillus pasteurianus powder contains more than 100 million live bacteria, and the bacterial liquid binder is composed of urea and calcium chloride in a ratio of 1:1. The mass composition of the internal rotary spraying slurry is 10 parts of glutinous rice paste, 10 parts of guar gum, 100 parts of clay, 20 parts of Bacillus pasteurianus powder, 20 parts of bacterial liquid binder and 160 parts of water.

[0084] Step 6: Implement boundary jet grouting drilling group at the boundary of coal mining working face. The boundary of coal mining working face includes opening eye, recovery line and two lanes. The final hole layer of boundary jet grouting drilling group is the bottom plate of water-proof soil layer. The boundary jet grouting drilling hole diameter is 1.0 times D2, that is, 0.38 meters. The boundary jet grouting drilling group is distributed along the boundary line, and the distance between adjacent boreholes is 40 meters. The jet grouting lifting speed v2 of the boundary jet grouting drilling hole is k 21 ×v=0.6×0.2=0.12m / min, where v is the normal lifting speed, which is 0.2m / min; k 21 is the correction coefficient of the lifting speed of the boundary jet jet drilling hole. Since (T2-T)÷T=(79.2-74)÷74=0.07 is greater than 0.01, it is taken as 0.6. The total amount of jet jet slurry in a single boundary jet jet drilling hole is Q2=k 22 ×(T2÷v2×Q)=1.5×(79.2÷0.12×100)=99000L=99m 3 , where k 22 The correction coefficient for the grouting volume of the boundary jet grouting drilling hole is 1.5, and Q is the normal grouting speed, which is 100L / min. The injection pressure of the boundary jet grouting drilling hole is P2=P+ΔP2=200-0.15=199.85MPa, where P is the normal grouting pressure, which is 20MPa; ΔP2 is the average additional stress at the boundary of the coal mining working face, which is obtained through known numerical simulation or physical simulation experiments, and the simulation result is -0.15MPa.

[0085] The composition of the boundary rotary spraying slurry includes glutinous rice paste, guar gum, clay, Bacillus pasteurianus powder, bacterial liquid binder and water. Among them, each gram of Bacillus pasteurianus powder contains more than 100 million live bacteria, and the bacterial liquid binder is composed of urea and calcium chloride in a ratio of 1:1. The mass composition of the boundary rotary spraying slurry is 20 parts of glutinous rice paste, 10 parts of guar gum, 100 parts of clay, 50 parts of Bacillus pasteurianus powder, 50 parts of bacterial liquid binder and 230 parts of water.

[0086] After adopting the coal mining water-proof soil layer rotary grouting reconstruction method of the present invention, the water inflow of the mine is reduced by 67%, the decline of the ecological water level is significantly controlled, the ground ecology slowly recovers after atmospheric precipitation, and the ecological environment is protected.

[0087] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for regenerating a water-proof soil layer by rotary grouting in coal mining, characterized in that: include: Before mining at the coal face, the thickness of the impermeable soil layer is obtained according to the borehole histogram; In the coal mining stage, the periodic pressure step and the initial pressure step are obtained through mine pressure observation; After the coal mining is completed at the coal mining face, multiple detection boreholes are drilled on the ground of the coal mining area; and the average thickness of the internal crushed swelling water-proof soil layer of the coal mining face and the average thickness of the boundary crushed swelling water-proof soil layer of the coal mining face are obtained according to the detection boreholes; the terminal hole position of each detection borehole is located at the bottom plate of the coal seam; After the coal mining subsidence is stabilized, the average width of the internal surface cracks and the average width of the boundary surface cracks of the coal mining working face are obtained through ground observation; Implement an internal rotary jet drilling group inside the coal mining face; the final hole layer of the internal rotary jet drilling group is the bottom plate of the water-proof soil layer, and multiple internal rotary jet drilling holes of the internal rotary jet drilling group are distributed along the periodic pressure line; the basic parameters of each internal rotary jet drilling hole are determined according to the thickness of the water-proof soil layer, the average thickness of the internal crushing and swelling water-proof soil layer and the average width of the internal surface cracks; A boundary rotary jet drilling group is implemented at the boundary of the coal mining working face; the final hole layer of the boundary rotary jet drilling group is the bottom plate of the water-impermeable soil layer, and the multiple boundary rotary jet drilling holes of the boundary rotary jet drilling group are distributed along the boundary line; the basic parameters of each boundary rotary jet drilling hole are determined according to the thickness of the water-impermeable soil layer, the average thickness of the boundary crushing water-impermeable soil layer and the average width of the boundary surface cracks.

2. A method for regenerating a water-repellent soil layer during coal mining by rotary grouting according to claim 1, characterized in that: After the coal mining is completed at the coal mining face, at least six detection drill holes are implemented on the ground of the coal mining area; wherein, at least three of the detection drill holes are arranged within the range of one cycle pressure step distance from the center position of the coal mining face; at least three of the detection drill holes are arranged within the coal mining face and within the range of one initial pressure step distance from the opening of the cutting eye.

3. A method for regenerating a water-repellent soil layer during coal mining by rotary grouting according to claim 1, characterized in that: The components of the jet slurry of the internal jet drilling hole and the boundary jet drilling hole include glutinous rice paste, guar gum, clay, Bacillus pasteurianus powder, bacterial liquid binder and water.

4. A method for regenerating a water-proof soil layer by rotary grouting in coal mining according to claim 3, characterized in that: The number of live bacteria contained in each gram of the Bacillus pasteurianus powder is greater than 100 million; the bacterial liquid binder is composed of urea and calcium chloride in a ratio of 1:

1.

5. A method for regenerating a water-proof soil layer by rotary grouting in coal mining according to claim 3 or 4, characterized in that: The rotary jet slurry for the internal rotary jet drilling hole comprises 10-20 parts of glutinous rice slurry, 10-20 parts of guar gum, 100-200 parts of clay, 20-60 parts of pasteurian bacillus powder, 20-60 parts of bacterial liquid cementing liquid and 160-360 parts of water.

6. A method for regenerating a water-proof soil layer during coal mining by rotary grouting according to claim 3 or 4, characterized in that: In the jet slurry for the boundary jet drilling, glutinous rice slurry accounts for 20-30 parts, guar gum accounts for 10-30 parts, clay accounts for 100-200 parts, Bacillus pasteurianus powder accounts for 50-100 parts, bacterial liquid cementing liquid accounts for 50-100 parts, and water accounts for 230-460 parts.

7. A method for regenerating a water-proof soil layer by rotary grouting in coal mining according to claim 1, characterized in that: The basic parameters of the internal jet grouting drilling include hole diameter, jet grouting lifting speed and total amount of jet grouting slurry; The diameter of the internal jet-jet drill hole is 1.0 to 1.2 times the average width of the internal surface cracks; The jet grouting lifting speed of the internal jet grouting drilling hole is: v1 = k 11 ×v; where v is the normal lifting speed; k 11 is the correction coefficient of the jet grouting lifting speed of the internal jet grouting drilling hole, when (T1-T)÷T is less than 0.01, it is taken as 0.8, when (T1-T)÷T is greater than or equal to 0.01, it is taken as 0.6; T1 represents the average thickness of the internal crushing and swelling water-proof soil layer; T represents the thickness of the water-proof soil layer; The total amount of the jet slurry in the internal jet drilling hole is: Q1 = k 12 ×(T1÷v1×Q); where k 12 is the correction coefficient for the grouting volume of internal jet grouting drilling; Q is the normal grouting rate.

8. A method for regenerating a water-proof soil layer by rotary grouting in coal mining according to claim 7, characterized in that: The basic parameters of the boundary jet grouting drilling hole include the hole diameter of the boundary jet grouting drilling hole, the jet grouting lifting speed and the total amount of the jet grouting slurry; The aperture of the boundary jet-jet drilling hole is 1.0 to 1.2 times the average width of the boundary surface cracks; The jet grouting lifting speed of the boundary jet grouting drilling hole is: v2 = k 21 ×v; where k 21 is the correction coefficient of the jet grouting lifting speed of the boundary jet grouting drilling hole, when (T2-T)÷T is less than 0.01, it is taken as 0.8, when (T2-T)÷T is greater than or equal to 0.01, it is taken as 0.6; T2 represents the average thickness of the boundary crushing and swelling water-proof soil layer; The total amount of jet slurry in the boundary jet drilling hole is: Q2 = k 22 ×(T2÷v2×Q); where k 22 It is the correction factor of grouting volume for boundary jet jet drilling.

9. A method for regenerating a water-proof soil layer during coal mining by rotary grouting according to claim 8, characterized in that: The basic parameters of the internal jet-jet drilling holes and the boundary jet-jet drilling holes also include the spacing between adjacent drilling holes and the jet pressure; The spacing between adjacent internal jet-jet holes is 10 to 30 meters. The injection pressure of the internal jet grouting drilling hole is: P1=P+ΔP1; wherein P is the normal grouting pressure; ΔP1 is the average additional stress inside the coal mining working face; The spacing between adjacent boreholes of the boundary jet-jet drilling holes is 20 to 50 meters; The injection pressure of the boundary rotary jet drilling hole is: P2=P+ΔP2, wherein ΔP2 is the average additional stress at the boundary of the coal mining working face.

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