A separation layer grouting casing device and a real-time detection and early warning method for the grouting process thereof

Abstract

The present invention relates to a delamination grouting casing device and a real-time detection and early warning method for the grouting process thereof, and relates to the field of delamination grouting in coal mine filling mining, comprising a grouting casing body, and also comprising a real-time detection circuit module placed on the surface of the grouting casing working surface for real-time detection of the grouting casing working status during the grouting operation; a casing centralizer sleeved on the outer surface of the grouting casing working surface, which can keep the grouting casing in the central working position in the borehole at all times; and a detection and early warning module connected to the real-time detection circuit module, which can provide multi-state graded early warning prompts for the detection status of the real-time detection circuit module. The patent of the present invention can realize real-time detection of the integrity of the delamination grouting casing without stopping the grouting, can detect whether the casing is pulled off or sheared due to rock movement, realize passive multi-layer grouting and slurry leakage early warning, can improve the effective injection-production ratio of delamination grouting, and thus improve the surface subsidence reduction effect.

Description

Technical Field

[0001] The present invention relates to the field of separation layer grouting in coal mine backfill mining, and in particular to a separation layer grouting casing device and a real-time detection and early warning method for a grouting process thereof. Background Art

[0002] The basic principle of stratum grouting technology is to inject fill material into the stratum stratum through surface drilling. This technique supports the key stratum, prevents its fracture, and controls overburden subsidence, ultimately reducing surface subsidence. Compared with other filling technologies, its greatest advantage is that grouting does not interfere with underground production, eliminating the need to change the existing mine development and production system. It also allows for the reuse of solid waste and protects the mining area's ecological environment.

[0003] However, due to the current lack of large-scale, high-precision, and fully overburden rock deformation monitoring equipment and methods in the industry, coupled with complex mine geological conditions, differences in mining and roof management methods, overburden strength and thickness, and mismatches between face recovery speed and grouting volume during grouting projects, failure to timely grouting often leads to closure of the separation space, which in turn causes the critical layer to continue to bend and sink, or even break. At this time, because the cementing cement casts the grouting casing and the rock wall in the borehole into a single entity, the grouting casing is affected by the movement of the rock layer, which manifests itself in two forms: tensile and shear failure. When the rock layer sinks due to instability, the casing is particularly prone to being pulled apart at the threaded connection. Since there are many threaded connections throughout the grouting pipeline, the fracture is random and hidden. Continuing high-pressure grouting on a grouting casing that has experienced tensile damage can have two harmful effects. First, the grouting from the threaded connection failure fracture will not support the critical layer. Instead, the grouting pressure will compress the critical layer, causing it to break prematurely, leading to increased surface subsidence. Second, when the threaded connection failure fracture appears above the bedrock surface, the grouting will leak along the interface between the Quaternary system and the bedrock, causing large-scale grouting. The grouting channel is hidden, and the leakage point is usually several kilometers away from the grouting hole, resulting in severe grouting waste and environmental damage. Therefore, when the casing breaks, appropriate remedial measures must be taken promptly.

[0004] Chinese patent application CN201910942330.5, entitled “Method for determining the position of overburden isolation grouting filling layer based on borehole injection flow measurement”, discloses a real-time detection method for the grouting layer that does not affect the normal implementation of grouting filling. The flow meter is used for segmented measurement in the casing. The grouting filling layer can be determined according to the change in flow rate. It can also be used to determine whether the casing has broken and the position of slurry leakage. However, the existing detection method mainly relies on the grouting orifice pressure gauge and the borehole television. When the orifice pressure gauge shows a drastic change in the reading, it is necessary to lower the borehole television to the inside of the grouting casing to find out the situation. The finding process requires stopping the grouting, injecting clean water to clean the inner wall of the casing, and disassembling the connection between the grouting orifice and the surface slurry pipeline. The detection process usually takes 1-2 days. At this time, the abscission space is very likely to close prematurely due to the lack of grouting pressure support, thereby affecting the subsequent grouting work and even the subsidence reduction effect. At the same time, it is necessary to add a blowout preventer to the wellhead device. At the beginning and end of the measurement work, the connection between the grouting pipeline and the grouting orifice needs to be disassembled so that the flow meter can be lowered with the help of the grouting drill pipe, which increases the complexity of the grouting pipeline and equipment and the cumbersomeness of the detection process. Summary of the Invention

[0005] Purpose of the invention: To provide a separation layer grouting casing device, and further provide a real-time detection and early warning method based on the above separation layer grouting casing device and its grouting process, so as to solve the above problems existing in the prior art.

[0006] Technical solution: A delamination grouting casing device includes a grouting casing body, and further includes three parts: a real-time detection line module, a casing centralizer and a detection and early warning module.

[0007] Among them, the real-time detection circuit module is placed on the surface of the grouting casing working surface, and is used to perform real-time detection of the grouting casing working status during the grouting operation; the casing centralizer is sleeved on the outer surface of the grouting casing working surface, so that the grouting casing can always maintain a centered working position in the borehole; the detection and early warning module is connected to the real-time detection circuit module, and can provide multi-state graded early warning prompts for the detection status of the real-time detection circuit module.

[0008] The overall operating length of the real-time detection line module is adapted to the grouting casing, and the real-time detection line module is placed between the outer surface of the grouting casing operating surface and the inner surface of the casing centralizer, and can perform corresponding fixing operations through the casing centralizer.

[0009] In a further embodiment, the real-time detection circuit module includes three parts: a power supply battery, a resistor, and an ammeter. The resistors are multiple and interconnected in parallel to form a corresponding parallel resistor string. The detection and warning module is a low-voltage alarm. The power supply battery, ammeter, and low-voltage alarm are connected in series with the parallel resistor string composed of multiple resistors, and can perform corresponding warning processing operations based on the corresponding operating status of the parallel resistor string. The outer surface of the operating surface of the real-time detection circuit module is wrapped with an insulating protective layer. The insulating protective layer is made of polyvinyl chloride plastic and can perform predetermined insulation protection operations on the real-time detection circuit module.

[0010] In a further embodiment, the real-time detection circuit module is strip-shaped, with the electronic components interconnected by insulated metal wires. The overall operating width is less than 2 cm, and the overall operating thickness of the circuit is less than 0.5 cm. The strip-shaped detection circuit occupies a small volume in the borehole, which does not affect the normal lowering of the casing and cementing. An orifice pressure gauge is installed at a predetermined position on the grouting filling borehole orifice, and the corresponding surface settlement operation can be controlled by controlling the pressure value of the orifice pressure gauge.

[0011] In a further embodiment, the resistance values of the plurality of resistors are equal, and according to the total resistance calculation formula of the parallel resistor line, R 总 =R / n. When rock formation movement causes the casing to break at the threaded connection due to tension, the disconnected casing and the line resistor also detach from the busbar, causing a significant change in the test line resistance value. At this time, the change in the current reading at the grouting hole on the surface can be used to infer the change in the line resistance value and determine the casing breakage.

[0012] In a further embodiment, the calculation formula for controlling the surface settlement value of the orifice pressure gauge is: P 孔 =P 注 -H1γ1≥P 地 -H1γ1=H1(γ-γ1); where P 孔 is the borehole pressure; P 注 is the grouting pressure of the underground grouting layer; P 地 is the formation pressure between the surface and the underground grouting layer; H1 is the hole depth from the surface to the grouting layer; γ is the comprehensive specific gravity of the formation above the grouting layer, 2500kg / m 3 ;γ1 is the specific gravity of filling slurry.

[0013] A method for real-time detection and early warning of a grouting process of a separation layer grouting casing device comprises the following steps:

[0014] S1. Before implementing the separation grouting project, drill holes in the overburden of the coal mining face, draw a borehole histogram, and identify the geological conditions and spatial distribution. Test the physical and mechanical parameters of the core rock to predict the number and location of key layers, and calculate the height of the water-conducting fracture zone according to the "three-under" coal mining (a general term for coal mining techniques under buildings, railways, and water bodies).

[0015] S2. Determine the grouting layer according to the height of the water-conducting fracture zone and the location of the key layer, and divide the stratum into normal area, remedial grouting area and early warning area;

[0016] S3. Lay out the grouting borehole and the real-time detection line module, lower the grouting casing, and synchronize the real-time detection line module and the grouting casing from the drilling tower into the borehole. Start the real-time detection line module and the detection and warning module, and judge the real-time operation status of the grouting casing by comparing the current displayed on the ammeter and the graded warning prompts of the detection and warning module.

[0017] S4. If the real-time detection line module is normal, the detection and warning module will light up with a green light. If the grouting casing breaks in the remedial grouting area, the detection and warning module will light up with a yellow light, and the staff will need to adjust the corresponding grouting pressure. If the grouting casing breaks in the warning area, the detection and warning module will light up with a red light, and the staff will need to stop the grouting operation.

[0018] In a further embodiment, the stratum zoning method is specifically to use the stratum space below the low sub-critical layer as the normal grouting area, the stratum above the low sub-critical layer to the main critical layer as the remedial grouting area, and the stratum above the main critical layer to the surface as the early warning area.

[0019] In a further embodiment, the low voltage alarm, the ammeter and the orifice pressure gauge are all placed above the ground to facilitate corresponding real-time observation and control operations.

[0020] Beneficial effects: A delamination grouting casing device and a real-time detection and early warning method for the grouting process thereof, which relates to the field of delamination grouting in coal mine filling mining, comprises a grouting casing body, and also comprises a real-time detection circuit module placed on the surface of the grouting casing working surface for real-time detection of the grouting casing working status during the grouting operation; a casing straightener sleeved on the outer surface of the grouting casing working surface, which can keep the grouting casing in the central working position in the borehole at all times; a detection and early warning module connected to the real-time detection circuit module, which can provide multi-state graded early warning prompts for the detection status of the real-time detection circuit module. The beneficial effects brought about by the technical solution of the present invention are: it can realize real-time detection of casing during the grouting process without stopping grouting, avoiding the tedious steps of stopping grouting, cleaning the inner wall of the casing, and inserting a drilling television in traditional detection, and can realize passive multi-layer grouting, effectively improving the injection-production ratio and increasing the surface subsidence rate. It can realize early warning of slurry leakage and avoid slurry waste and environmental pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram for real-time detection of the assembly position of the line module and grouting casing.

[0022] Figure 2 Schematic diagram of the fixed coupling between the grouting casing and the real-time detection line module.

[0023] Figure 3 This is a schematic diagram of the grouting casing after the threaded connection is broken.

[0024] Figure 4 Schematic diagram of the grouting casing centralizer.

[0025] Figure 5 Schematic diagram of rock formation and grouting casing with timely grouting under ideal conditions.

[0026] Figure 6 Schematic diagram of rock formation breakage and grouting casing damage when grouting is not timely filled.

[0027] Figure 7 Schematic diagram of the entire process of grouting casing and real-time detection line module layout and operation.

[0028] Figure 8 for Figure 1 The enlarged schematic diagram of the line connection of the real-time detection circuit module shown in area A in the middle.

[0029] Figure 9 for Figure 3 An enlarged schematic diagram of the line connection when the real-time detection line module in areas B and C is broken.

[0030] The reference numerals in the figure are: grouting casing 1, real-time detection circuit module 2, power battery 21, ammeter 22, resistor 23, low voltage alarm 24, grouting casing threaded connection 3, casing centralizer 4, cement mortar 5, borehole 6, orifice pressure gauge 7, surface slurry pipeline 8, main key layer 9, high sub-key layer 10, low sub-key layer 11, injectable layer space 12, coal mining working face 13, interface between topsoil and bedrock 14, normal area 15, remedial area 16, and early warning area 17. DETAILED DESCRIPTION

[0031] In the following description, numerous specific details are provided to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without one or more of these details. In other instances, certain technical features well known in the art are not described to avoid confusion with the present invention.

[0032] The applicant believes that existing devices and methods for detecting delamination grouting casings are time-consuming and can lead to premature closure of the delamination space due to a lack of grouting pressure support, thus affecting subsequent grouting work and even the effectiveness of subsidence reduction. Furthermore, at the beginning and end of the measurement and testing work, the connection between the grouting pipeline and the grouting orifice must be disconnected in order to lower the flow meter via the grouting drill pipe, which increases the complexity of the grouting pipeline and equipment and the cumbersomeness of the testing process.

[0033] To this end, the applicant designed a delamination grouting casing device and a real-time detection and early warning method for the grouting process, so as to realize real-time detection of the integrity of the delamination grouting casing without stopping the grouting. It can detect whether the casing is pulled apart or sheared due to rock movement, realize passive multi-layer grouting and slurry leakage early warning, and improve the effective injection-production ratio of delamination grouting, thereby improving the surface subsidence reduction effect.

[0034] The present invention provides a real-time detection method for a delamination grouting casing 1 without stopping grouting, which is suitable for detecting casing breakage positions caused by overburden migration, can prevent grout leakage and realize passive multi-layer grouting.

[0035] The delamination grouting casing 1 device of the present invention includes a grouting casing 1 body, and further includes three parts: a real-time detection circuit module 2, a casing centralizer 4, and a detection and warning module. Among them, the real-time detection circuit module 2 is placed on the working surface of the grouting casing 1, and is used to perform real-time detection of the working status of the grouting casing 1 during the grouting operation; the casing centralizer 4 is sleeved on the outer surface of the working surface of the grouting casing 1, so that the grouting casing 1 can always maintain a centered working position in the borehole 6; the detection and warning module is connected to the real-time detection circuit module 2, and can provide multi-state graded warning prompts for the detection status of the real-time detection circuit module 2. The overall operating length of the real-time detection circuit module 2 is compatible with the grouting casing 1, and the real-time detection circuit module 2 is placed between the outer surface of the working surface of the grouting casing 1 and the inner surface of the casing centralizer 4, and can perform corresponding fixing operations through the casing centralizer 4. The real-time detection circuit module 2 includes three parts: a power supply battery 21, a resistor 23 and an ammeter 22. There are multiple resistors 23, which are connected to each other in parallel to form a corresponding parallel resistor 23 string. The detection and early warning module is a low voltage alarm 24. The power supply battery 21, the ammeter 22 and the low voltage alarm 24 are connected in series with the parallel resistor 23 string composed of multiple resistors 23. The corresponding early warning processing operation can be performed according to the corresponding operating status of the parallel resistor 23 string. The outer surface of the operating surface of the real-time detection circuit module 2 is wrapped with an insulating protective layer. The insulating protective layer is made of polyvinyl chloride plastic material and can perform predetermined insulation protection operations on the real-time detection circuit module 2. The low voltage alarm 24, the ammeter 22 and the orifice pressure gauge 7 are all placed above the ground to facilitate corresponding real-time observation and control operations.

[0036] The present invention mainly includes the composition and manufacturing method of the real-time detection line of casing integrity, the insertion and fixed coupling method of the detection line, the casing integrity detection principle and detection method, and the passive multi-layer grouting and slurry leakage early warning method.

[0037] Example 1: Composition and manufacturing method of real-time casing integrity detection circuit

[0038] The grouting sleeve 1 and the real-time detection circuit module 2 are arranged as follows Figure 1 As shown, since the space available for grouting in the separation layer is mostly located at a depth of hundreds of meters, it is necessary to use the grouting sleeve 1 as a grouting channel. The length of the grouting sleeve 1 is generally about 5m, and a threaded connection is used for deep hole grouting, such as Figure 3As shown. The main electronic components used in the real-time detection circuit module 2 include: a power battery 21, an ammeter 22, a resistor 23, and a low voltage alarm 24. The resistors 23 are connected in parallel using insulated copper wires. In particular, the resistance of each individual resistor 23 in parallel in the circuit is equal. The detection circuit is wrapped with polyvinyl chloride plastic as an insulating protective layer, and is thermoformed into a strip shape, such as Figure 8 As shown in , the width of the thermoplastic-molded strip-shaped detection line can be controlled within 2 cm and its thickness can be controlled within 0.5 cm. The detection line occupies a very small volume in the borehole 6 and does not affect the layout of the grouting sleeve 1. The low-voltage alarm 24 can produce variable sound and light to alert ground personnel of possible changes in the grouting sleeve 1.

[0039] Example 2: Detection circuit placement and fixed coupling method

[0040] When the grouting casing 1 and the real-time detection circuit module 2 are lowered into the borehole 6 by using a drilling tower, a casing centralizer 4 is required. Figure 4 As shown, the casing centralizer 4 plays two roles at this time. First, it fixes the real-time detection line module 2 so that the line fits on the casing surface. Second, it ensures that the grouting casing 1 is always located at the center of the borehole 6, which can prevent the real-time detection line module 2 from losing its measurement function due to wear between the grouting casing 1 and the rock wall of the borehole 6 during the lowering process.

[0041] The fixed coupling method of the real-time detection line module 2 and the grouting sleeve 1 is as follows Figure 2 As shown, a borehole 6 is arranged in advance on the surface of the goaf. The diameter of the borehole 6 should be slightly larger than the outer diameter of the grouting sleeve 1. Figure 2 In the method shown, the grouting sleeve 1 is lowered into the bottom of the borehole 6. When the grouting sleeve 1 is installed in place, the annular gap between the borehole 6 and the grouting sleeve 1 is filled with cement mortar 5. The purpose of cementing is twofold. First, it prevents the filling slurry from leaking from the annular gap during the grouting process. Second, it casts the rock mass around the borehole 6, the grouting sleeve 1, and the detection line into one. When the rock layer moves, the real-time detection line module 2 can return the change information of the sleeve to the surface through the detection line. The part of the real-time detection line module 2 above the ground includes a power battery 21, an ammeter 22, and a low voltage alarm 24. The above electronic components need to be placed in a box to prevent damage. After being cemented with cement mortar 5, the grouting sleeve 1 is connected to the surface orifice pressure gauge 7 and the surface grouting pipeline 8.

[0042] Example 3: Casing integrity detection principle and detection method

[0043] The integrity detection principle of the grouting casing 1 is as follows Figure 1 、 Figure 3 、 Figure 8and Figure 9 As shown, when the grouting sleeve 1 is not disturbed or is slightly disturbed by the rock formation, the grouting sleeve 1 is complete and each grouting sleeve 1 is tightly engaged at the threaded connection. At this time, the real-time detection line module 2 is as shown in FIG. Figure 8 As shown, the real-time detection circuit module 2 is intact, the resistance 23 of the insulated copper wire is ignored, and the resistance of each parallel resistor 23 is equal. According to the calculation formula of the total resistance of the parallel resistor 23, In particular, when R1=R2=R3=…R n-1 =R, R 总 =R / n. When the grouting sleeve 1 is pulled apart at the threaded connection due to rock formation movement, the disconnected grouting sleeve 1 and the resistor 23 of the line are also separated from the busbar, causing the resistance 23 value of the real-time detection line module 2 to change significantly. For example, a complete grouting path consists of 10 grouting sleeves 1, and the resistor 23 on each grouting sleeve 1 is 10 ohms. At this time, the resistance 23 value on the real-time detection line module 2 is R 总 =10 / 10=1 ohm; when the fifth and sixth casings on the grouting path are broken, the resistance value on the detection line is R 总 =10 / 5=2 ohms. At this time, the change in the value of the line resistance 23 can be inferred by the change in the reading of the ammeter 22 at the grouting hole on the surface, and the breakage of the grouting sleeve 1 can be calculated.

[0044] Example 4: Passive multi-layer grouting and grout leakage warning method

[0045] Ideally, the rock migration and grouting casing 1 status are timely. Figure 5 As shown in Figure 1, when a certain length of coal seam is mined, “three vertical zones” will be formed, including collapse zone, fracture zone, and curved subsidence zone. The collapse zone and fracture zone are collectively called water-conducting fracture zone. The injectable layer space 12 appears below the key layer above the water-conducting fracture zone, as shown in Figure 1. Figure 5 As shown, the current injectable detachable space 12 is below the low sub-critical layer 11. If the grouting timing is well grasped and the filling is timely, the grouting pressure and the filling compaction body will play a role in the injectable detachable space 12, supporting the low sub-critical layer 11 and preventing it from breaking, thereby achieving the purpose of reducing surface settlement. At this time, it can be seen that due to the supporting effect, the deformation of the rock and soil from the low sub-critical layer 11 to the surface is very small, and it will not damage the grouting casing 1. This will also produce a virtuous cycle. The slurry transported by the casing near the cut eye keeps the detached space always connected to the subsequent grouting casing 1. The normal operation of the subsequent grouting work can in turn protect the casing from being pulled apart and damaged by rock migration.

[0046] However, the existing rock movement monitoring equipment and prediction methods cannot accurately predict the location and scale of the separation, so the separation grouting project often faces the problem of untimely grouting. The unfilled separation space 12 will be closed as the coal mining face 13 advances, resulting in the closure of the low-level separation space. Figure 6 As shown, at this time, the rock formation loses support and will bend and sink downward, causing the grouting sleeve 1 to break. According to the real-time detection line module 2, the grouting sleeve 1 is judged to have a broken position. When the broken position is located in the high sub-critical layer 10 or the delamination space under the main critical layer 9, the grouting can still play a role in supporting the critical layer and thus achieve the purpose of reducing surface subsidence. If the broken position is located at or above the interface between the topsoil and the bedrock, continuing grouting may cause slurry leakage. According to the above description, the entire stratum can be divided into three areas: normal area 15, remedial area 16, and early warning area 17.

[0047] When the grouting casing 1 is not broken, the grouting casing 1 is connected to the separation space below the low sub-critical layer 11. At this time, the detection line is normal, and the ground low voltage alarm 24 lights up green, indicating that the grouting casing 1 is complete at this time; when the grouting casing 1 breaks at the remedial area 16, the ground low voltage alarm 24 lights up yellow, indicating that the grouting casing 1 is broken, prompting the ground staff to adjust the grouting pressure; when the grouting casing 1 breaks at the early warning area 17, the ground low voltage alarm 24 lights up red, indicating that the grouting casing 1 is broken at this time in the early warning area above the main critical layer 9, prompting the staff to stop grouting. In order to prevent the grouting pressure from being too high and slurry leakage, the grouting pressure needs to be adjusted according to the grouting casing 1 break position. The principle of grouting pressure adjustment is: the grouting pressure should not be less than the natural ground pressure of the stratum above the grouting filling layer to ensure surface stability. In actual construction, the grouting pressure P at the top of the grouting filling borehole 6 can be controlled. 孔 To achieve the control of surface settlement. The layout and operation adjustment principles of detection lines and grouting casings are as follows: Figure 7 The calculation formula of the orifice pressure gauge used to control the surface settlement value is: P 孔 =P 注 -H1γ1≥P 地 -H1γ1=H1(γ-γ1); where: P 孔 is the borehole pressure of borehole 6; P 注 is the grouting pressure of the underground grouting layer; P 地 is the formation pressure between the surface and the underground grouting layer; H1 is the hole depth from the surface to the grouting layer; γ is the comprehensive specific gravity of the formation above the grouting layer, 2500kg / m 3 ;γ1 is the specific gravity of filling slurry.

[0048] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes may be made to it in form and detail without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A separation layer grouting casing device, comprising a grouting casing (1), characterized in that Also includes: A real-time detection circuit module (2) is placed on the working surface of the grouting sleeve (1) and is used to perform real-time detection of the working condition of the grouting sleeve (1) during the grouting operation; A casing centralizer (4) is sleeved on the outer surface of the working surface of the grouting casing (1), so that the grouting casing (1) can always maintain a central working position in the drill hole (6); A detection and warning module is connected to the real-time detection circuit module (2) and can provide a multi-state graded warning prompt for the real-time detection status of the real-time detection circuit module (2); The overall operating length of the real-time detection line module (2) is adapted to the grouting sleeve (1), and the real-time detection line module (2) is placed between the outer surface of the operating surface of the grouting sleeve (1) and the inner surface of the sleeve centralizer (4), and can be fixed by the sleeve centralizer (4); The real-time detection circuit module includes a power supply battery (21), a resistor (23) and an ammeter (22), and the resistors (23) are multiple and interconnected in parallel to form a corresponding parallel resistor string; The detection and warning module is a low voltage alarm (24), and the power supply battery (21), the ammeter (22), the low voltage alarm (24) and a parallel resistor string composed of a plurality of resistors (23) are connected in series; The outer surface of the working surface of the real-time detection circuit module (2) is wrapped with an insulating protective layer, and a predetermined insulation protection operation can be performed on the real-time detection circuit module (2); The real-time detection circuit module (2) is strip-shaped, and the electronic components are interconnected through insulated metal wires, the overall operation width is less than 2 cm, and the overall operation thickness of the circuit is less than 0.5 cm; An orifice pressure gauge (7) is provided at a predetermined position of the orifice of the grouting filling borehole (6), and the corresponding surface settlement operation can be controlled by controlling the pressure value of the orifice pressure gauge (7); The calculation formula for controlling the surface settlement value of the orifice pressure gauge (7) is: Where: is the drill mouth pressure of the borehole (6); is the grouting pressure of the underground grouting layer; is the formation pressure between the surface and the underground grouting layer; is the hole depth from the ground surface to the grouting layer; is the comprehensive weight of the strata above the injection level, 2500 ; is the specific gravity of the filling slurry.

2. The separation layer grouting casing device according to claim 1, characterized in that: The resistance values of the plurality of resistors (23) are equal, and the total resistance of the parallel resistors (23) is , where n is the total number of resistors (23), and R is the resistance value of the resistor (23).

3. A method for real-time detection and early warning of the grouting process of a separation layer grouting casing device according to any one of claims 1 to 2, characterized in that The following steps are involved: S1. Before implementing the separation grouting project, drill holes (6) in the overburden of the coal mining face (13), draw a histogram of the holes (6), and find out the geological conditions and spatial distribution; test the physical and mechanical parameters of the core, predict the number and location of the key layers, and calculate the height of the water-conducting fracture zone according to the "three-down" coal mining specifications; S2. Determine the grouting layer according to the height of the water-conducting fracture zone and the location of the key layer, and divide the stratum into the normal zone (15), the remedial grouting zone and the early warning zone (17); S3, laying out the grouting borehole (6) and the real-time detection line module (2), lowering the grouting casing (1), so that the real-time detection line module (2) and the grouting casing (1) are synchronously lowered from the drilling tower into the borehole (6), starting the real-time detection line module (2) and the detection and warning module, and judging the real-time operation status of the grouting casing (1) by comparing the current amount shown by the ammeter (22) and the graded warning prompt of the detection and warning module; S4, the real-time detection line module (2) is normal, and the detection warning module lights up green to indicate; When the rupture position of the grouting sleeve (1) occurs in the remedial grouting area, the detection and warning module lights up a yellow light to prompt the staff to adjust the corresponding grouting pressure; when the rupture position of the grouting sleeve (1) occurs in the warning area (17), the detection and warning module lights up a red light to prompt the staff to stop the grouting operation.

4. The method for real-time detection and early warning of the grouting process of the separation layer grouting casing device according to claim 3 is characterized in that: The stratum partitioning method is specifically as follows: The abscission space below the low sub-critical layer (11) is used as the normal zone (15), the stratum above the low sub-critical layer (11) to the main critical layer (9) is used as the remedial grouting zone, and the stratum above the main critical layer (9) to the surface is used as the warning zone (17).

5. The separation layer grouting casing device according to claim 1, characterized in that: The low voltage alarm (24), the ammeter (22) and the orifice pressure gauge (7) are all placed above the ground to facilitate corresponding real-time observation and control operations.

Images