A method for grouting overburden separation layer under water shortage conditions

Abstract

The present application relates to a method for grouting overburden separation under water-deficient conditions, which belongs to the field of grouting filling coal mining. The method sequentially comprises the steps of designing and calculating, establishing a grouting passage, conducting a water extraction and discharge experiment, determining a stable flow rate, grouting, adjusting the grouting volume and the water extraction volume, restoring the grouting water supply volume, and switching the grouting flower pipe mode. A circulation passage is established through different grouting channels in combination with the sandstone layer. When the water that penetrates into the sandstone layer during the grouting process diffuses to the grouting channels for water extraction, the water will be extracted and returned to the slurry making station for recycling, thereby achieving the purpose of increasing the water supply in water-deficient mines or during grouting water-deficient periods.

Description

Technical Field

[0001] The present application relates to the field of grouting and filling coal mining, and in particular to a method for grouting overburden separation layer under water shortage conditions. Background Art

[0002] In recent years, with the large-scale exploitation of coal resources, a large number of goafs have been formed. The exploitation of underground coal seams will inevitably cause the settlement and migration of overlying rock strata. The changes in the strata have further developed into negative problems such as water inrush, sand burst, and surface subsidence. Among them, the problem of surface subsidence is particularly obvious. It not only causes the destruction of fertile fields and cultivated land and the damage of buildings, but also easily causes environmental problems such as soil erosion and land desertification. At present, for the problem of surface subsidence, delamination grouting and subsidence reduction technology has become a technology of greater concern because it does not affect normal underground mining.

[0003] For example, a Chinese invention application with publication number CN116557051A discloses a method for grouting and filling overburden strata. However, the prerequisite for using this grouting and filling method is that the local water source is sufficient. It has great limitations in water-scarce areas. Often, many coal mining areas cannot provide sufficient mine water for filling. Summary of the invention

[0004] In order to improve the above problems, the present application provides a method for grouting the overburden separation layer under water shortage conditions.

[0005] The present application provides a method for grouting overburden separation layers under water shortage conditions, which adopts the following technical solutions:

[0006] A method for grouting overburden separation layers under water shortage conditions comprises the following steps in sequence:

[0007] S1: Design the arrangement spacing of the grouting positions, analyze the depth of the grouting layer according to the formation conditions, calculate the grouting volume and grouting water supply, design the solid particle size in the slurry, and the grouting layer is between the sandstone layer and the mudstone layer;

[0008] S2: Establish a grouting station, drill holes at each grouting position to form grouting channels, lower the grouting flower pipe to the grouting layer, connect the hole mouth to the grouting or pumping device, and connect the grouting channel to the grouting station through the grouting or pumping device;

[0009] S3: Pumping and releasing water to determine the stable flow rate;

[0010] S4: grouting along each arranged grouting channel;

[0011] S5: Reduce the grouting water supply, extract the separated water through the adjacent grouting holes, and determine the stable pumping volume;

[0012] S6: transport the extracted separated water to the slurry making station to restore the grouting water supply;

[0013] S7: When the mining face advances to the grouting channel where water is being pumped, connect this grouting channel to the grouting pipeline of the slurry station.

[0014] By adopting the above technical solution, the water that penetrates into the sandstone layer during the grouting process will be extracted and returned to the slurry making station for recycling when it diffuses to the grouting holes for pumping water, thereby achieving the purpose of increasing the water supply in water-deficient mines or during grouting water-deficient periods.

[0015] Preferably, the grouting material includes water and gangue powder, and the water-cement ratio is 1:1.

[0016] Preferably, in S2, a casing is placed in the grouting channel, a cement protective wall is provided outside the casing, the grouting flower pipe is located at the lower end of the casing and the two are coaxial, a plurality of water filter holes are opened on the pipe wall of the grouting flower pipe, an overlapping section is provided between the grouting flower pipe and the casing, and the boundary line between the sandstone layer and the mudstone layer is located within the length range of the grouting flower pipe.

[0017] By adopting the above technical solution, the grouting layer is located between the sandstone layer and the mudstone layer. The sandstone layer is a key layer that needs to be protected, and the grouting flower pipe is located here for grouting.

[0018] Preferably, the pore size of the water filter hole is 15 mm, and the particle size of the gangue powder is 60-80 mesh.

[0019] Preferably, a star-shaped plate core is provided in the grouting flower tube, and the star-shaped plate core includes a plurality of partition plates fixedly connected to each other, each of the partition plates is arranged in a circular array with the axis of the grouting flower tube as the center, and the plate surface of the partition plate is parallel to the axis of the grouting flower tube.

[0020] By adopting the above technical solution, the separated water in the sandstone layer moves under the action of the grouting pressure. For the grouting tube used in the pumping stage, the water pressure on the side of the grouting tube close to the grouting state is relatively large, while the water pressure on the side of the grouting tube away from the grouting state is relatively small. The separated water entering the grouting tube through the water filter hole directly impacts the partition plate, reducing the lateral kinetic energy of this part of the water and improving the recovery rate of the separated water.

[0021] Preferably, the star-shaped plate core is located within the height range of the sandstone layer, a settlement space is formed in the grouting tube and below the star-shaped plate core, an intercepting piece is provided at the upper edge of the partition plate, and the intercepting piece is located in the space between two adjacent partition plates.

[0022] By adopting the above technical solution, the intercepting element can increase the obstruction to the water flow during pumping, and increase the probability and proportion of the sedimentation of particulate impurities in the water.

[0023] Preferably, the intercepting member is a movable plate, one side edge of the movable plate is hinged to the upper side edge of the partition plate, the movable plate is located within the height range of the partition plate, and the rotation angle range of the movable plate is 0-90°.

[0024] By adopting the above technical solution, during the pumping process, the upward water flow generates thrust on the movable plate, so that the angle between the movable plate and the partition plate is approximately 90°, so that during the upward flow of water in the grouting flower tube, the movable plate can always generate resistance to the water flow; during grouting, the star-shaped plate core moves downward under the action of the grouting pressure, and after the movable plate is impacted by the slurry, the angle between it and the partition plate tends to 0°, which has little impact on the grouting slurry.

[0025] Preferably, a switching valve is provided in the settlement space of the grouting tube, the switching valve and the grouting tube are movably connected, and the movement of the switching valve relative to the grouting tube is used to control the unblocking condition of the water filter holes within the mudstone layer.

[0026] Preferably, the switching valve is an adjusting cylinder, and the adjusting cylinder and the grouting flower tube are coaxially rotatably connected. A matching hole is opened on the adjusting cylinder, and the matching hole corresponds to the water filter hole. The star-shaped plate core and the grouting flower tube are slidably connected, and the sliding direction is the axial direction of the grouting flower tube. A transmission block is fixedly connected to the star-shaped plate core, and a spiral guide groove is opened on the wall of the adjusting cylinder, and the transmission block is located in the spiral guide groove.

[0027] By adopting the above technical scheme, during the pumping stage, the matching pores and the water filter holes of the switching valve are not aligned, so that the water filter holes are blocked. During grouting, each water filter hole is aligned with the corresponding matching pore, and the water filter holes within the mudstone layer are connected, so that the slurry can be diffused through the water filter holes within the length of the entire grouting tube; when the star-shaped plate core moves vertically, the transmission block generates a lateral abutment force on the wall of the spiral guide groove, causing the adjusting cylinder to rotate, thereby changing the position of the matching pores and realizing the function of the switching valve.

[0028] In summary, the present application includes at least one of the following beneficial technical effects:

[0029] 1. By extracting the separated water to the pulping station, the water that penetrates into the sandstone layer during the grouting process will be extracted and returned to the pulping station for recycling when it diffuses to the grouting hole for pumping water, thereby achieving the purpose of increasing the water supply in the water-deficient mine or the period of grouting water shortage;

[0030] 2. Through the setting of the switching valve, during the pumping stage, the switching valve blocks the water filter hole, and the material flow inside and outside the grouting tube within the mudstone layer is relatively small, so the components in the mudstone layer are not easy to enter the grouting tube and be extracted by the pumping device. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a flow chart of the overburden separation grouting method in the embodiment of the present application for reflecting the water shortage situation.

[0032] Figure 2 It is a structural schematic diagram used to reflect a slurry making station, a sandstone layer, a mudstone layer and a plurality of grouting channels in an embodiment of the present application.

[0033] Figure 3 It is a structural schematic diagram used to reflect the grouting layer and the bottom of the grouting channel in the embodiment of the present application.

[0034] Figure 4 It is a schematic diagram used to reflect the grouting channel switching mode in the embodiment of the present application.

[0035] Figure 5 It is a cross-sectional schematic diagram used to illustrate the internal structure of the flower tube in the embodiment of the present application.

[0036] Figure 6 It is a schematic diagram of the structure inside the flower tube in the embodiment of the present application.

[0037] Explanation of the accompanying reference numerals: 1. Grouting layer; 11. Sandstone layer; 12. Mudstone layer; 2. Slurry-making station; 21. Grouting channel; 3. Grouting flower pipe; 31. Drain hole; 32. Sedimentation space; 4. Star-shaped plate core; 41. Partition plate; 42. Movable plate; 43. Transmission block; 5. Switching valve; 51. Adjusting cylinder; 52. Matching gap; 53. Spiral guide groove. DETAILED DESCRIPTION

[0038] The following is combined with Figure 1-6 This application is described in further detail.

[0039] The present application embodiment discloses a method for grouting the overburden layer under water shortage conditions, such as Figure 1-4 As shown, the following steps are included in sequence:

[0040] S1: Design and calculation: Design the arrangement spacing of the grouting positions, analyze the depth of the grouting layer 1 according to the formation conditions, calculate the grouting volume and the water supply for slurry preparation, and design the solid particle size in the slurry. The grouting layer 1 is between the sandstone layer 11 and the mudstone layer 12. The sandstone layer 11 is located above the mudstone layer 12. The sandstone layer 11 is a key layer that needs to be protected, and the mudstone layer 12 has water-proof properties. The grouting material is a mixture of water and gangue powder, and the water-cement ratio is 1:1. In this embodiment, the design spacing of the grouting holes is 100m, the minimum daily water requirement is 3500m³, and the design water supply is 4000m³ per day.

[0041] S2: Establishing a grouting passage: Establishing a grouting station 2, drilling holes at each grouting position to form a grouting channel 21, lowering a grouting flower pipe 3 to the position of the grouting layer 1, connecting the orifice with a grouting or pumping device, connecting the grouting channel 21 to the grouting or pumping device and the grouting station 2, placing a casing in the grouting channel 21, and providing a cement wall protection outside the casing, the grouting flower pipe 3 is located at the lower end of the casing and the two are coaxial, and there is an overlapping section between the grouting flower pipe 3 and the casing, and the distance of the overlapping section is 2-5 meters, and a plurality of water filtering holes 31 are opened on the pipe wall of the grouting flower pipe 3, and the boundary line between the sandstone layer 11 and the mudstone layer 12 is located in the middle of the length range of the grouting flower pipe 3;

[0042] S3: Water extraction and discharge experiment, determination of stable flow rate: During the grouting process, the pressure between the sandstone layer 11 and the mudstone layer 12 increases, the water in the slurry is separated under pressure, penetrates into the sandstone layer 11, and diffuses laterally through the sandstone layer 11. According to the set grouting pressure test, the self-flow rate of separated water in the sandstone layer 11 is 50m³ / h;

[0043] S4: Grouting: Grouting is performed along each arranged grouting channel 21;

[0044] S5: Adjust the grouting volume and pumping volume: As the grouting progresses, the underground mine water decreases, and the grouting water supply is reduced to 3000 m³ / d, and then the separated water is extracted through the adjacent grouting hole 21 to determine the stable pumping volume of 1000 m³ / d;

[0045] S6: Restore grouting water supply: transport the extracted separated water to the slurry station 2, and restore the total grouting water supply to 4000m³ / d;

[0046] S7: Mode switching: When the mining face (boundary of the grouting layer) advances to the grouting channel 21 that is being pumped, the grouting channel 21 is connected to the grouting pipeline of the slurry station 2, and the grouting channel originally used for pumping water is switched to the grouting mode.

[0047] like Figure 3 As shown, in this embodiment, the diameter of the water filter holes 31 of the grouting flower tube 3 is 15 mm, and eight rows of water filter holes 31 are arranged along the circumference of the grouting flower tube 3; the particle size of the gangue powder is 60-80 mesh.

[0048] like Figure 5 and 6As shown, a star-shaped plate core 4 is slidably arranged in the grouting tube 3, and the sliding direction is the axial direction of the grouting tube 3. The star-shaped plate core 4 includes a plurality of mutually fixedly connected partition plates 41, each partition plate 41 is arranged in a circular array with the axis of the grouting tube 3 as the center, the plate surface of the partition plate 41 is parallel to the axis of the grouting tube 3, and there are six partition plates 41 in total. In the projection along the axial direction of the grouting tube 3, the cross section of the star-shaped plate core 4 is approximately in the shape of a hexagonal star, and a fan-shaped gap is formed between each adjacent two partition plates 41. The separated water of the sandstone layer 11 moves under the action of the grouting pressure. For the grouting tube 3 used in the pumping stage, the water pressure on the side of the grouting tube 3 close to the grouting state is relatively large, while the water pressure on the side of the grouting tube 3 away from the grouting state is relatively small. The separated water entering the grouting tube 3 through the water filter hole 31 directly impacts the partition plate 41, reducing the lateral kinetic energy of this part of water and improving the recovery rate of the separated water.

[0049] like Figure 5 and 6 As shown, the star-shaped plate core 4 is located within the height range of the sandstone layer 11, and a settling space 32 is formed in the grouting flower tube 3 and below the star-shaped plate core 4. A switching valve 5 is provided in the grouting flower tube 3 and in the settling space 32. The switching valve 5 and the grouting flower tube 3 are movably connected. The movement of the switching valve 5 relative to the grouting flower tube 3 is used to control the blocking of the water filter holes 31 within the mudstone layer 12. During the pumping process, the switching valve 5 blocks the water filter holes 31 within the mudstone layer 12, thereby reducing the material exchange inside and outside the grouting flower tube 3 at the mudstone layer 12. When the separated water enters the grouting flower tube 3, the granular impurities contained therein will settle due to the sudden decrease in flow rate, and the settling space 32 is used for the deposition of impurities that are stalled and settled. The switching valve 5 is an adjusting cylinder 51, which is coaxially rotatably connected to the grouting flower tube 3. The adjusting cylinder 51 is provided with eight matching pores 52 arranged in a circular array. The outline of the matching pores 52 is a rectangle, and a single matching pore 52 corresponds to a row of water filter holes 31; during the pumping stage, the matching pores 52 and the water filter holes 31 are not aligned, that is, the water filter holes 31 are blocked.

[0050] like Figure 5 and 6As shown, in order to improve the interception effect of separating particulate impurities in the water during the pumping process, an interception member is provided on the upper edge of the partition plate 41, and the interception member is located in the space between two adjacent partition plates 41. In this embodiment, the interception member is a movable plate 42, one side edge of the movable plate 42 is hinged to the upper side edge of the partition plate 41, the hinge axis and the straight line where the upper edge of the partition plate 41 is located are parallel, the movable plate 42 is always located within the height range of the partition plate 41 during the rotation process, and the rotation angle range of the movable plate 42 is 0-90°, and during the pumping process, the upward water flow generates thrust on the movable plate 42, so that the angle between the movable plate 42 and the partition plate 41 is approximately 90°, so that during the upward flow of water in the grouting flower tube 3, the movable plate 42 can always generate resistance to the water flow.

[0051] like Figure 5 and 6 As shown, in S7, when the grouting flower tube 3 is switched from the pumping mode to the grouting mode, the water filtering holes 31 within the mudstone layer 12 need to be opened. A transmission block 43 is fixedly connected to the star-shaped plate core 4, and a spiral guide groove 53 is provided on the wall of the adjusting cylinder 51. The transmission block 43 is located in the spiral guide groove 53. The vertical length of the spiral guide groove 53 is the moving stroke distance of the star-shaped plate core 4, and the distance value is 30 cm. When pumping water, the star-shaped plate core 4 is in a higher position under the pressure of the water flow. During grouting, the star-shaped plate core 4 moves downward under the action of the grouting pressure. After the movable plate 42 is impacted by the slurry, the angle between it and the partition plate 41 tends to 0°. When the star-shaped plate core 4 moves 30 cm, the transmission block 43 generates a lateral abutment force on the wall of the spiral guide groove 53, causing the adjusting cylinder 51 to rotate 20°. Each column of water filter holes 31 is aligned with the corresponding matching pores 52, and the water filter holes 31 within the mudstone layer 12 are connected, so that the slurry can be diffused through the water filter holes 31 within the length of the entire grouting flower tube 3.

[0052] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for grouting overburden separation layer under water shortage conditions, characterized in that: The steps are as follows: S1: Design the arrangement spacing of the grouting positions, analyze the depth of the grouting layer (1) according to the formation conditions, calculate the grouting amount and the grouting water supply, and design the solid particle size in the slurry. The grouting layer (1) is located between the sandstone layer (11) and the mudstone layer (12); S2: Establishing a grouting station (2), drilling holes at various grouting positions to form grouting channels (21), lowering a grouting flower pipe (3) to the grouting layer (1), connecting the hole opening to a grouting or pumping device, and connecting the grouting channel (21) to the grouting station (2) via the grouting or pumping device; S3: Pumping and releasing water to determine the stable flow rate; S4: performing grouting along each arranged grouting channel (21); S5: reducing the grouting water supply, extracting separated water through adjacent grouting holes (21), and determining a stable water extraction volume; S6: transporting the extracted separated water to the slurry station (2) to restore the grouting water supply; S7: When the mining working face advances to the grouting channel (21) where water is being pumped, the grouting channel (21) is connected to the grouting pipeline of the slurry station (2); Grouting materials include water and gangue powder, with a water-cement ratio of 1:1; In S2, a casing is placed in the grouting channel (21), a cement wall is provided outside the casing, the grouting flower pipe (3) is located at the lower end of the casing and the two are coaxial, a plurality of water filter holes (31) are opened on the wall of the grouting flower pipe (3), an overlapping section is provided between the grouting flower pipe (3) and the casing, and the boundary line between the sandstone layer (11) and the mudstone layer (12) is located within the length range of the grouting flower pipe (3); A star-shaped plate core (4) is provided inside the grouting flower tube (3), and the star-shaped plate core (4) comprises a plurality of partition plates (41) fixedly connected to each other, and each of the partition plates (41) is arranged in a circular array with the axis of the grouting flower tube (3) as the center, and the plate surface of the partition plate (41) is parallel to the axis of the grouting flower tube (3); The star-shaped plate core (4) is located within the height range of the sandstone layer (11), a settlement space (32) is formed in the grouting flower tube (3) and below the star-shaped plate core (4), and an interception member is provided at the upper edge of the partition plate (41), and the interception member is located in the space between two adjacent partition plates (41); A switching valve (5) is provided in the sedimentation space (32) of the grouting flower tube (3); the switching valve (5) and the grouting flower tube (3) are movably connected; the movement of the switching valve (5) relative to the grouting flower tube (3) is used to control the unblocking condition of the water filter holes (31) within the mudstone layer (12).

2. The method for grouting overburden separation layer under water shortage conditions according to claim 1 is characterized in that: The pore size of the water filter hole (31) is 15 mm, and the particle size of the gangue powder is 60-80 mesh.

3. The method for grouting overburden separation layer under water shortage conditions according to claim 1 is characterized in that: The intercepting member is a movable plate (42), one side edge of the movable plate (42) is hinged to the upper side edge of the partition plate (41), the movable plate (42) is located within the height range of the partition plate (41), and the rotation angle range of the movable plate (42) is 0-90°.

4. The method for grouting overburden separation layer under water shortage conditions according to claim 1 is characterized in that: The switching valve (5) is an adjusting cylinder (51), the adjusting cylinder (51) and the grouting flower tube (3) are coaxially rotatably connected, a matching hole (52) is provided on the adjusting cylinder (51), and the matching hole (52) corresponds to the water filter hole (31), the star-shaped plate core (4) and the grouting flower tube (3) are slidably connected, and the sliding direction is the axial direction of the grouting flower tube (3), a transmission block (43) is fixedly connected to the star-shaped plate core (4), a spiral guide groove (53) is provided on the cylinder wall of the adjusting cylinder (51), and the transmission block (43) is located in the spiral guide groove (53).

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