Drainage method after filling of sublevel open stope subsequent goaf

Abstract

The invention relates to the field of mine engineering, in particular to a drainage method after filling of a sublevel open stoping subsequent goaf, which comprises the following steps of: determining a drilling position in a roadway connected with a to-be-filled goaf; drilling from the drilling position to the laneway below to form a drainage hole for communicating the laneway and the laneway; a water drainage sleeve is installed in the water drainage hole, and a main water drainage channel is formed through an inner cavity of the water drainage sleeve; when the goaf is filled, water separated out from the filling body is automatically discharged to the roadway from the roadway under the action of gravity through the main drainage channel. According to the embodiment of the invention, the preset gravity flow drainage channel is used for replacing the traditional manual pumping and drainage operation, so that the labor intensity is reduced, the risk of roadway flooding caused by untimely drainage is avoided, and the production continuity is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of mining engineering, specifically to a drainage method for subsequent backfilling of segmented open areas.

[0002] The present invention also relates to a drainage structure for subsequent filling of a segmented goaf. Background Technology

[0003] Subgrade backfilling is one of the key technologies in underground mining. After the ore is extracted and a goaf is formed, hydraulic backfill slurry needs to be pumped into the goaf. During the solidification process of the slurry, a large amount of mixing water will be released. If this water cannot be discharged in a timely and effective manner, serious problems will occur. Especially in mines with poor surrounding rock geological conditions (for example, the rock is mainly phyllite that is prone to mudification when exposed to water), if the roadway is soaked by the released water for a long time, the strength of the surrounding rock will be significantly reduced, which can easily lead to roadway deformation or even collapse, posing a major safety hazard.

[0004] refer to Figure 1 The current common temporary treatment method in the industry is to build a temporary retaining dam with waste rock or sandbags outside the retaining wall at the exit of the goaf to intercept and collect the water seeping from the filter holes of the retaining wall; then, auxiliary workers are arranged to regularly use water pumps to pump away the accumulated water.

[0005] This method has obvious drawbacks: First, it requires continuous manpower for pumping operations, which is labor-intensive and inefficient; second, the amount of water intercepted by the retaining dam is limited, and if the amount of water overflows too much or the pumping is not timely, it is very easy to overflow, causing the main transport roadway to be flooded, interrupting production and further damaging the stability of the roadway.

[0006] Therefore, developing a technical solution that can automatically, continuously and reliably drain backfill water is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] The purpose of this invention is to provide a drainage method for subsequent filling of goaf in segmented goaf areas. By pre-constructing drainage channels from the goaf area to the roadway, it realizes automatic gravity flow drainage of water, which significantly improves the safety of mining operations.

[0008] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution: A drainage method for subsequent backfilling of segmented goaf areas is applied in a mine with multiple roadways, and goaf areas to be backfilled exist between these roadways. The drainage method includes the following steps: Step 1: Determine the drilling location within the roadway connected to the goaf to be filled; Step 2: Drill a drainage hole connecting the two tunnels from the location of the borehole upwards or downwards; Step 3: Install a drain sleeve inside the drain hole to form a main drainage channel using the inner cavity of the drain sleeve; Step 4: When the goaf is filled, the water that has separated from the filling body is automatically discharged from the upper roadway to the lower roadway by gravity through the main drainage channel.

[0009] Furthermore, it also includes the step of forming secondary drainage channels: In step three, a drainage sleeve with an outer diameter smaller than that of the drainage hole is used, and at least one centralizer is installed on its outer wall. The centralizer is used to keep the drainage sleeve centered in the drainage hole, thereby forming an annular space between the outer wall of the drainage sleeve and the hole wall of the drainage hole. Water-permeable filter material is filled into the annular space to form a secondary drainage channel connecting the two tunnels.

[0010] Furthermore, the step of filling the annular space with permeable filter media includes: 1. Install a feeding and conveying device at the port of the drainage hole located in the lower roadway; 2. The high-pressure air is mixed with the water-permeable filter material by the feeding and conveying device to form a gas-solid two-phase flow, and the gas-solid two-phase flow is blown upward along the annular space until it is completely filled.

[0011] Furthermore, the feeding and conveying device includes: Feed hopper, used to hold the permeable filter media; The jet pump has its inlet connected to the bottom of the feeding hopper and is equipped with a main airflow nozzle connected to a high-pressure air source. A conveying pipe, one end of which is connected to the outlet of the jet pump.

[0012] Furthermore, the feeding and conveying device also includes an interface component for connecting it to the drain port, the interface component comprising: A plug is used to seal the lower opening of the drain sleeve during filling operations; A connector is fitted over the outside of the plug and fixed to the drain port of the lower tunnel. The bottom of the connector is connected to the conveying pipe, and the top of the connector forms an annular feeding channel connecting the annular space with the plug. A sealing ring is disposed between the connector and the wall of the drain hole.

[0013] Furthermore, the step of mixing high-pressure air with the water-permeable filter media and blowing it in specifically involves: High-pressure air is introduced into the jet pump, and the negative pressure effect generated by the high-speed airflow draws the permeable filter material from the feeding hopper and accelerates it, forming the gas-solid two-phase flow in the jet pump. Then, the gas-solid two-phase flow is guided to be injected into the annular space through the conveying pipe and the annular feeding channel of the joint.

[0014] Furthermore, In step three, the drain sleeve has at least one tangential inlet on the inlet end of the pipe wall in the upper roadway. The axis of the tangential inlet is tangential to the inner wall of the drain sleeve, which is used to guide the water flow to form a spiral vortex with self-cleaning effect in the main drainage channel.

[0015] Furthermore, Multiple spiral-shaped flow-guiding grooves are provided on the inner wall of the drain sleeve, which are consistent with the rotation direction of the spiral vortex, to capture solid particles in the water flow under the action of the vortex to form a sacrificial protective layer; Furthermore, the depth of the guide groove decreases gradually from the inlet end to the outlet end of the drain sleeve.

[0016] Furthermore, the installation steps in step three specifically include: Multiple independent annular modules with constant-depth internal flow-guiding grooves are spliced ​​along their axial direction to form the complete drainage sleeve. Specifically, by sequentially splicing the annular modules with different groove depths in descending order of depth, a flow guide groove with a gradient decreasing groove depth is formed.

[0017] Furthermore, the steps for assembling the ring module specifically include: The annular clamp of the stabilizer is fitted onto the connection between two adjacent annular modules to simultaneously achieve the connection and fixation of the two annular modules and their centered positioning within the drain hole.

[0018] The advantages of this invention compared to the prior art are: The embodiments of the present invention use a pre-set gravity flow drainage channel to replace the traditional manual pumping operation, which reduces labor intensity, avoids the risk of flooding of the tunnel due to untimely drainage, and ensures the continuity of production. Attached Figure Description

[0019] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the existing temporary processing methods; Figure 2 This is a schematic diagram of the basic drainage structure of Embodiment 1 of the invention; Figure 3 This is a three-dimensional schematic diagram of Embodiment 2 of the invention; Figure 4 This is a three-dimensional schematic diagram of the connection relationship between the drain sleeve and the stabilizer in Embodiment 2 of the invention; Figure 5 This is a cross-sectional view of the feeding and conveying device according to Embodiment 2 of the invention; Figure 6 This is a schematic diagram illustrating the formation of the tangential water inlet in Embodiment 3 of the invention; Figure 7 This is a front view of the drain sleeve according to Embodiment 3 of the invention; Figure 8 for Figure 7 A cross-sectional view along the AA direction; Figure 9 This is an assembly drawing of the drain sleeve and the stabilizer in Embodiment 3 of the invention; The labels in the diagram represent the following: 1-Goaf; 2-Tunnel; 3-Retaining wall; 4-Retaining dam; 5-Drainage hole; 6-Drainage sleeve; 61-Tangential water inlet; 62-Guide groove; 63-Annular module; 7-Annular space; 8-Center; 81-Ring clamp; 82-Support arm; 91-Feeding hopper; 92-Jet pump; 93-Conveying pipeline; 94-Plug; 95-Joint; 96-Sealing ring. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The water drainage method of the present invention includes the following basic steps: 1. Before or after the formation of the goaf 1 to be filled, select one or more locations within the roadway 2 connecting the goaf 1.

[0023] 2. From the aforementioned location, drill one or more drainage holes 5 that connect to adjacent tunnels 2 downwards.

[0024] 3. A drain sleeve 6 is installed inside the drain hole 5, and the inner cavity of the drain sleeve 6 forms a drainage channel.

[0025] Fourth, when the goaf 1 is filled, the water released from the filling material flows into the roadway 2 and is automatically discharged into the roadway 2 below under the action of gravity through the drainage channel of the drainage sleeve 6.

[0026] (Example 1) refer to Figure 2 This embodiment discloses the basic implementation method of the present invention.

[0027] Taking the drainage hole 5 connecting the -358m section and the -343m section as an example: First, on the bottom slab of the -343m section of tunnel 2, the drilling location is planned and determined. This location is usually adjacent to the filling retaining wall 3. Using a medium-deep hole drilling rig, one or more drainage holes 5 are drilled from this location down to the -358m section of tunnel 2 at a certain angle.

[0028] Subsequently, a smooth-walled PVC or steel drainage sleeve 6 is installed into each drainage hole 5. Its outer diameter is slightly smaller than the diameter of the drainage hole 5. After installation, the drainage sleeve 6 constitutes a permanent drainage channel for the tunnel 2 from the -343m section to the -358m section.

[0029] When the goaf 1 of the -343m section is filled, the water released from the filling slurry seeps into the roadway 2 through the retaining wall 3, collects and flows into the drainage casing 6, and under the action of gravity, it automatically and continuously flows into the drainage ditch of the -358m roadway 2, and finally flows into the main drainage structure of the mine.

[0030] This embodiment can complete drainage without manual intervention, which helps to solve the problem of water accumulation in alleys.

[0031] (Example 2) refer to Figure 3 , Figure 4 , Figure 5 This embodiment discloses a preferred embodiment of the invention, which aims to provide a more stable and reliable drainage structure.

[0032] First, in the -358m section of tunnel 2, a drainage hole 5 is drilled upwards to the -343m section of tunnel 2; the difference is that the diameter of the drainage hole 5 drilled in this embodiment is larger, at 150mm.

[0033] Next, select a drain sleeve 6 with an outer diameter of 100mm; install a stabilizer 8 every 3 meters on the outer wall of the sleeve.

[0034] The stabilizer 8 includes a steel ring clamp 81, on which multiple radially distributed, outwardly extending elastic steel support arms 82 are welded. The outer diameter formed by the ends of all the support arms 82 is approximately 145 mm, which is slightly smaller than the 150 mm diameter of the drain hole 5.

[0035] Finally, the drain sleeve 6 with the stabilizer 8 is pushed from the end of the tunnel 2 into the drain hole 5.

[0036] The function of the stabilizer 8 is to keep the drain sleeve 6 centered in the drain hole 5, thereby forming a uniform annular space 7 of about 25mm between its outer wall and the wall of the drain hole 5.

[0037] On the other hand, the centering device 8 is not only used for centering, but the elasticity of its support arm 82 can also provide outward radial pressure, increasing the friction with the hole wall of the drain hole 5, thereby playing a fixing role.

[0038] After the drain sleeve 6 is fully installed, its top end can be fixed with anchoring agent, anchor rod or special orifice sealing device to prevent accidental movement.

[0039] A filter screen or filter element is installed at the inlet end of the drain hole 5 to prevent large particles (such as coarse aggregate in the filling slurry) from entering the casing and causing blockage.

[0040] After the above steps are completed, the filter media filling operation of the annular space 7 is carried out. The specific method is as follows: First, install a dedicated feeding hopper 91 at the drain hole 5 in the tunnel 2. Add clean gravel with a particle size of 5-10mm into the feeding hopper 91, and at the same time introduce high-pressure air through the air inlet of the feeding hopper 91.

[0041] Second, using the principle of pneumatic conveying, the gravel is blown by high-pressure air and transported upward along the annular space 7 and gradually filled. The density of the filling can be controlled by observing the changes in air volume and pressure at the exhaust port.

[0042] refer to Figure 5 In order to achieve pneumatic conveying, this embodiment adopts a special feeding and conveying device, which includes: feeding hopper 91, jet pump 92, conveying pipe 93, plug 94, connector 95 and sealing ring 96.

[0043] The feed hopper 91 is used to temporarily store clean gravel with a particle size of 5-10mm. It is equipped with an adjustable gate valve (not shown in the figure) at the bottom to precisely control the falling rate of the gravel.

[0044] The bottom of the feeding hopper 91 is connected to the feed inlet of the jet pump 92 via a flange. A high-pressure air source (such as an air compressor) is connected to the main airflow nozzle of the jet pump 92 via a high-pressure hose. The discharge port of the jet pump 92 is connected to the conveying pipe 93.

[0045] The plug 94 is installed at the bottom of the drain sleeve 6 to prevent gravel from entering its inner cavity. The connector 95 is fixed to the bottom of the drain hole 5 by expansion bolts drilled into the top of the tunnel. The connector 95 covers the outside of the plug 94, and its top and the plug 94 form an annular feeding channel, which communicates with the annular space 7. The bottom of the connector 95 is connected to the conveying pipe 93, thereby establishing a complete conveying path from the ground to the annular space 7.

[0046] A sealing ring 96 is placed between the connector 95 and the drain hole 5 to form a high-pressure seal during transportation and prevent high-pressure air leakage.

[0047] During the gravel filling operation, when high-pressure air flows at high speed in the jet pump 92, it generates negative pressure around it, using the Venturi effect to draw in and accelerate the gravel falling from the feed hopper 91. Subsequently, the mixture of gravel and air enters the jet pump 92 to form a uniform and stable gas-solid two-phase flow. The gas-solid two-phase flow is sent from the conveying pipe 93 through the connector 95 into the annular space 7. When the gravel collides with the support arm 82 of the stabilizer 8, it drives the support arm 82 to deform slightly inward, allowing the gravel to pass through the gap between the annular clamp 81 and the drain sleeve 6 and continue to move upward. Then, the support arm will return to its original position due to elasticity. After the gravel filling is completed, due to the friction and locking effect between the gravel and the support arm 82, the support arm 82 will prevent the gravel from moving downward, thus providing a preliminary fixing effect for subsequent permanent sealing.

[0048] After completing the above steps, the filter media (e.g., gravel, coarse sand) in the annular space 7 forms a permeable secondary drainage channel. When the water precipitated from the filling body seeps into the surrounding rock mass of the drainage hole 5 or the tiny gaps between the filling body and the surrounding rock, this part of the water will enter the annular space 7 and permeate downward through the gravel layer.

[0049] This structure forms a composite drainage structure, including: Main channel: The inner cavity of the drain sleeve 6 is used to drain most of the relatively clear water.

[0050] Secondary channel: The filter layer within the annular space 7 is used to drain water seeping from the surrounding rock or backfill.

[0051] Working principle: The main and secondary channels work together. Even if the main channel is not draining properly for some reason (such as a small amount of fine particles accumulating), the secondary channel can still provide additional drainage capacity, improving the reliability of the drainage structure.

[0052] When the filling operation is carried out, the precipitated water can not only be discharged through the inner cavity (main channel) of the drain sleeve 6, but also seep into the gravel layer (secondary channel) in the annular space 7 and then be discharged downward along the space.

[0053] This composite drainage structure provides dual drainage protection, and the drainage sleeve 6 is isolated by the gravel layer and surrounding rock, which enhances its resistance to ground pressure and deformation, helping to ensure the long-term stability and reliability of the drainage structure during the mine's service life.

[0054] (Example 3) The risk of blockage in Example 1 stems from the large number of fine suspended particles carried in the backfill water, which can enter the drain sleeve 6 with the water flow and deposit and clump therein.

[0055] refer to Figure 6 , Figure 7 Example 3 is an improvement on Example 2, which aims to solve the problem of blockage that may occur after long-term operation of the basic drainage structure.

[0056] To solve this problem, in this embodiment, the drain sleeve 6 is provided with at least one tangential inlet 61 on the pipe wall at the inlet end of the upper tunnel 2. The axis of the inlet 61 does not point to the center of the drain sleeve 6, but is tangential to its inner wall.

[0057] The working principle is as follows: When the water carrying particles enters from the tangential inlet 61, the gravitational potential energy of the water flow is converted into angular kinetic energy, forming a high-speed and stable spiral vortex in the inner cavity of the drain sleeve 6, which continuously scours the inner wall of the pipe and effectively prevents the deposition and adhesion of fine particles.

[0058] In addition, the central region of the vortex generates negative pressure due to the high flow velocity, which can enhance the suction effect of drainage to a certain extent. Through this design, the drainage structure gains the ability to actively self-clean, alleviate the blockage problem caused by siltation, and ensure its long-term operational reliability.

[0059] Although the self-cleaning vortex solves the blockage, the high concentration and high hardness of rock powder and other particles it carries will cause continuous scouring and wear on the inner wall of the drain sleeve 6, affecting its service life.

[0060] Preferred, Reference Figure 7 , Figure 8 To address the pipe wall wear problem caused by high-speed eddies, the solution in this embodiment is to process multiple spiral-shaped flow-guiding grooves 62 on the inner wall of the drain sleeve 6, with the spiral direction of these flow-guiding grooves 62 being consistent with the rotation direction of the eddies.

[0061] The working principle is as follows: Under the action of the spiral vortex, the denser solid particles are thrown towards the pipe wall due to centrifugal force. When these particles move to the vicinity of the guide groove 62, due to the change in local flow velocity and pressure, some particles will be captured and deposited inside the groove. Over time, the deposited particles will gradually fill the groove and form a stable and dynamically renewable sacrificial protective layer.

[0062] This sacrificial protective layer, composed of the particles themselves, effectively isolates the original pipe wall of the drain sleeve 6 from the direct scouring of solid particles in the subsequent water flow. Wear and tear then mainly occurs on this renewable sacrificial protective layer, while the pipe body itself is effectively protected.

[0063] Since the sacrificial protective layer, while protecting the pipe wall, inevitably occupies a portion of the effective water flow area, it may slightly affect the drainage efficiency when the amount of leakage is large.

[0064] Preferred, Reference Figure 8 In order to balance the self-protection function and the efficient drainage function, the flow guide groove 62 in this embodiment is designed as a variable depth structure: the depth of the flow guide groove 62 decreases gradually from the inlet end of the drain sleeve 6 to the outlet end.

[0065] The working principle is as follows: At the inlet end, a deeper groove is needed to quickly capture particles in order to form an initial sacrificial protective layer as soon as possible. After the water flows into the pipe for a certain distance, some particles have been captured and the sand content of the water flow has been reduced. At this time, a shallower groove can be used to maintain the stability of the protective layer and maximize the water flow area of ​​the drainage channel.

[0066] This variable depth design allows the drainage sleeve 6 to dynamically coordinate protection and drainage functions under different operating stages and different water flow conditions, ensuring that the system can operate efficiently and stably throughout its entire life cycle.

[0067] Because the drain sleeve 6 is an integral long pipe with a complex inner wall geometry (such as a variable depth spiral groove), it is difficult, costly and has a low yield when manufactured using traditional extrusion or processing technology, which restricts its engineering application.

[0068] Preferred, Reference Figure 9 This embodiment proposes a modular and splicing manufacturing scheme: the scheme decomposes a complete drainage sleeve 6 into multiple independent standardized ring modules 63 with simple geometric features. Each ring module 63 is relatively short, and its internal flow guiding groove 62 can be designed with a constant depth. By combining modules with different groove depths, a complete sleeve with a variable depth groove can be spliced ​​together.

[0069] For example, various specifications of annular modules 63 with groove depths of 5mm, 4mm, 3mm and 2mm can be pre-produced in batches. During on-site installation, these modules are assembled into a complete drain sleeve 6 by splicing them together with simple connection structures (such as threads, snaps or flanges) according to design requirements.

[0070] Preferably, the straightener 8 connects the ends of two annular modules 63 through the friction of its own annular clamp 81, and several annular modules 63 are connected in series by the straightener 8.

[0071] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered as falling within the scope of protection of the embodiments of the present invention.

Claims

1. A drainage method for subsequent backfilling of segmented goaf areas, applied in a mine having multiple roadways, with goaf areas to be backfilled existing between the roadways, characterized in that... The drainage method includes the following steps: Step 1: Determine the drilling location in the roadway (2) connected to the goaf to be filled (1); Step 2: Drill a drainage hole (5) connecting the two tunnels (2) from the drilling location upwards or downwards. Step 3: Install a drain sleeve (6) inside the drain hole (5) to form a main drainage channel using the inner cavity of the drain sleeve (6); Step 4: When the goaf (1) is filled, the water that is separated from the filling body is automatically discharged from the upper roadway (2) to the lower roadway (2) by gravity through the main drainage channel.

2. The drainage method according to claim 1, characterized in that, It also includes the step of forming secondary drainage channels: In step three, a drainage sleeve (6) with an outer diameter smaller than that of the drainage hole (5) is used, and at least one centralizer (8) is installed on its outer wall. The centralizer (8) is used to keep the drainage sleeve (6) centered in the drainage hole (5), thereby forming an annular space (7) between the outer wall of the drainage sleeve (6) and the hole wall of the drainage hole (5). The annular space (7) is filled with permeable filter material to form a secondary drainage channel connecting the two tunnels (2).

3. The drainage method according to claim 2, characterized in that, The step of filling the annular space (7) with permeable filter media includes:

1. Install a feeding and conveying device at the port of the drainage hole (5) located in the lower roadway (2); 2. The high-pressure air is mixed with the water-permeable filter material by the feeding and conveying device to form a gas-solid two-phase flow, and the gas-solid two-phase flow is blown upward along the annular space (7) until it is completely filled.

4. The drainage method according to claim 3, characterized in that, The feeding and conveying device includes: Feed hopper (91) is used to hold the permeable filter media; The jet pump (92) has its inlet connected to the bottom of the feed hopper (91) and is equipped with a main airflow nozzle connected to a high-pressure air source; The conveying pipe (93) is connected at one end to the outlet of the jet pump (92).

5. The drainage method according to claim 4, characterized in that, The feeding and conveying device further includes an interface component for connecting it to the drain hole (5) port, the interface component comprising: A plug (94) is used to seal the lower opening of the drain sleeve (6) during filling operations; The connector (95) is covered outside the plug (94) and fixed to the drain hole (5) port of the lower tunnel (2). The bottom of the connector (95) is connected to the conveying pipe (93), and its top forms an annular feeding channel connecting the annular space (7) with the plug (94). A sealing ring (96) is disposed between the connector (95) and the wall of the drain hole (5).

6. The drainage method according to claim 5, characterized in that, The specific steps of mixing high-pressure air with water-permeable filter media and blowing it in are as follows: High-pressure air is introduced into the jet pump (92), and the water-permeable filter material is sucked in from the feed hopper (91) and accelerated by the negative pressure effect generated by the high-speed airflow. The gas-solid two-phase flow is formed in the jet pump (92), and then the gas-solid two-phase flow is guided to be injected into the annular space (7) through the annular feed channel of the conveying pipe (93) and the connector (95).

7. The drainage method according to claim 2, characterized in that, In step three, the drain sleeve (6) is provided with at least one tangential inlet (61) on the inlet end pipe wall of the upper tunnel (2). The axis of the tangential inlet (61) is tangential to the inner wall of the drain sleeve (6) and is used to guide the water flow to form a spiral vortex with self-cleaning effect in the main drainage channel.

8. The drainage method according to claim 7, characterized in that, Multiple spiral guide grooves (62) are provided on the inner wall of the drain sleeve (6) in the same direction as the rotation of the spiral vortex, which are used to capture solid particles in the water flow under the action of the vortex to form a sacrificial protective layer. Furthermore, the depth of the guide groove (62) decreases gradually from the inlet end to the outlet end of the drain sleeve (6).

9. The drainage method according to claim 8, characterized in that, The installation steps in step three specifically include: Multiple independent annular modules (63) with constant-depth internal flow-guiding grooves (62) are spliced ​​along their axial direction to form the complete drain sleeve (6). Among them, by splicing the annular modules (63) with different groove depths in descending order of depth, a flow guide groove (62) with a gradient decrease in groove depth is formed.

10. The drainage method according to claim 9, characterized in that, The steps for assembling the ring module (63) specifically include: The annular clamp (81) of the stabilizer (8) is fitted onto the connection of two adjacent annular modules (63) to simultaneously achieve the connection and fixation of the two annular modules (63) and their centered positioning within the drain hole (5).

Images