Controllable seepage pumping and draining type underground stope filling and dewatering method and controllable seepage pumping and draining type underground stope filling and dewatering system

Abstract

The invention provides a controllable seepage pumping and draining type underground stope filling and dewatering method and a controllable seepage pumping and draining type underground stope filling and dewatering system. Relates to the technical field of mine engineering. The filling dehydration method comprises the steps that a dehydration pipeline is arranged, and the water outlet end of the dehydration pipeline is led out of a goaf; the water outlet end is communicated with a negative pressure pumping drainage device; conveying the filling slurry; and starting the negative-pressure pumping and draining device, sucking water in the filling slurry into the dewatering pipeline by utilizing pressure difference, and draining the water out of the goaf. According to the method, active suction force generated by the negative pressure environment is used for replacing traditional gravity drive, the dehydration rate and efficiency of the filling slurry are remarkably improved, dissipation of pore water pressure and solidification of the filling body are accelerated, and the safety of filling operation and the mechanical stability of the filling body are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of mining engineering technology, and more specifically, to a controllable seepage drainage method and system for filling and dewatering underground mining areas. Background Technology

[0002] In underground mine backfilling mining, the backfilling method is widely used because it can effectively control ground pressure and realize the resource utilization of solid waste. To ensure the fluidity of the backfill slurry during pipeline transportation, a high water-cement ratio is usually maintained, resulting in a large water content in the slurry. However, if excess free water cannot be drained promptly and effectively after the slurry is filled into the stope, it will seriously affect the consolidation quality of the backfill and the safety of the stope. Therefore, efficient dewatering of backfilled stopes is a key link in ensuring safe mine production and backfill quality.

[0003] Currently, existing dewatering measures mainly rely on pre-reserved filter holes in the backfill retaining wall or the laying of flexible dewatering pipes at the bottom and edges of the mining area. These traditional methods primarily utilize the self-weight stress of the backfill slurry to create a hydrostatic pressure difference, driving water through geotextiles or filters for natural infiltration and discharge. This method is essentially a passive drainage system, with its drainage power entirely dependent on the gravity field and the slurry level.

[0004] However, the aforementioned existing technologies have many insurmountable drawbacks in practical applications. First, the passive gravity-driven power is very limited, making it difficult to overcome the capillary and pore resistance between fine-grained aggregates. Especially after the slurry settles or thickens due to hydration, the seepage rate is much lower than the settling rate, resulting in low and unstable dewatering efficiency. Second, existing drainage facilities are mostly arranged in a two-dimensional planar or peripheral manner. As the slurry level rises, the seepage path from the drainage channel in the center and upper areas of the stope increases significantly, causing a sharp drop in seepage velocity and forming large-scale "dewatering blind zones" in the deep and core areas of the stope. Furthermore, fine particles in the slurry easily migrate with the water flow to the surface of the filter medium and accumulate to form a dense layer. In addition, the hydration products of the cementitious materials easily crystallize in the pores, making the filter channels prone to physical blockage and chemical closure. Moreover, once the existing facilities are installed, they cannot be actively maintained by backwashing or dredging, which can easily lead to drainage system failure.

[0005] In summary, the existing technology suffers from insufficient dewatering driving force, limited space coverage, and easy and irreparable blockage of filter channels. These problems directly lead to severe gravity stratification and segregation of the filling slurry, resulting in uneven density and insufficient strength within the filling body. Furthermore, the long-term accumulation of excess pore water pressure within the slurry significantly increases the lateral pressure on the filling retaining wall, posing serious safety hazards such as leakage or collapse.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] The purpose of this invention is to provide a controllable seepage drainage method and system for dewatering underground mining fill. The method achieves active forced drainage of the filling slurry by establishing a negative pressure environment, which significantly improves the dewatering efficiency and accelerates the consolidation and stabilization of the filling body.

[0008] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: In a first aspect, the present invention provides a method for controlled seepage drainage type backfilling and dewatering of underground mining areas, comprising: A dewatering pipeline is installed inside the goaf to be filled, and the outlet of the dewatering pipeline is led out to the outside of the goaf. Connect the water outlet of the dewatering pipeline located outside the goaf to the negative pressure pumping device; The filling slurry is delivered into the goaf. During or after the filling operation, the negative pressure extraction device is activated to create a negative pressure environment inside the dewatering pipeline. The negative pressure environment is used to establish a pressure difference between the filling slurry and the dewatering pipeline, drawing water from the filling slurry into the dewatering pipeline and discharging it to the outside of the goaf.

[0009] In an optional implementation, the step of arranging dewatering pipelines inside the goaf to be filled includes: A pipeline system consisting of a main dewatering pipe and several auxiliary dewatering pipes is constructed within the goaf area; The main dewatering pipe is extended along the top plate or central area, and the auxiliary dewatering pipes are connected to the main dewatering pipe through joints, so that the auxiliary dewatering pipes extend into the internal space of the goaf to form a three-dimensional drainage network. Preferably, the connection and arrangement of the plurality of auxiliary dehydration pipes follow the following rules: Multiple rows of auxiliary dewatering pipes are arranged at intervals along the tunneling direction of the goaf. Adjust the angle of each row of auxiliary dewatering pipes so that they fan out relative to the main dewatering pipes to cover different depth levels of the goaf.

[0010] In an optional embodiment, the dehydration pipeline is made of a pipe with a composite structure; the composite structure includes a core plate as an internal support skeleton and a filter membrane covering the outside of the core plate; The method further includes: Before arranging the dewatering pipeline, the filter membrane with a matching pore size is selected based on the particle size distribution characteristics of the tailings and cementing materials in the filling slurry. Preferably, the step of activating the negative pressure extraction device adopts an intermittent extraction process: The negative pressure extraction device is controlled to periodically open and close, or the suction pressure is periodically adjusted; The periodic changes in pressure inside the dewatering pipeline drive the filter membrane to undergo micro-deformation relative to the core plate, thereby peeling off or loosening the filling slurry particles adsorbed on the surface of the filter membrane.

[0011] In an optional embodiment, the step of connecting the water outlet of the dewatering pipeline located outside the goaf area to the negative pressure pumping device further includes: A water-air separator is connected in series between the dehydration pipeline and the negative pressure extraction device. The fluid extracted from the goaf first enters the water-gas separation device for gas-liquid separation. The separated gas is extracted by the negative pressure extraction device, and the separated liquid is retained in the water-gas separation device or discharged separately.

[0012] In an optional embodiment, the controlled seepage drainage type underground mining area filling and dewatering method further includes a synergistic pressurization step: A reverse booster pipe, independent of the dewatering pipeline, is pre-installed inside the goaf; the reverse booster pipe is located inside or in the lower middle part of the goaf filling body. During the operation of the negative pressure extraction device, compressed gas or pressurizing medium is injected into the reverse pressurization pipe; By utilizing the negative pressure suction at the dewatering pipeline and the positive pressure at the reverse pressurization pipe, a directional pressure gradient is formed inside the filling slurry; Preferably, the selection of the reverse booster tube follows these rules: A permeable pipe with a microporous layer in its wall and overall deformable characteristics is selected as the reverse booster pipe; The microporous layer is used to prevent solid particles from entering the tube, and the deformable property is used to make the reverse pressure tube shrink or recover under external pressure changes to adapt to the deformation of the filling material.

[0013] Secondly, the present invention provides an underground mining area filling and dewatering system for implementing the controlled seepage drainage underground mining area filling and dewatering method described in the foregoing embodiments; the underground mining area filling and dewatering system includes: A dewatering pipeline assembly is configured to be arranged inside the goaf to be filled for collecting moisture from the filling slurry in the goaf. The negative pressure extraction device is configured to be arranged outside the goaf area and has a power mechanism to generate negative pressure suction. Pipeline connectors are used to connect the water outlet of the dehydration pipeline assembly to the air inlet of the negative pressure extraction device. When the negative pressure extraction device is started, a negative pressure environment is formed inside the dewatering pipeline assembly to drive the water in the filling slurry into the dewatering pipeline assembly.

[0014] In an optional embodiment, the dehydration piping assembly includes: The main dewatering pipe is used to extend along the direction of the goaf. Several auxiliary dewatering pipes are connected to the main dewatering pipe through joints and are distributed in a three-dimensional divergent manner relative to the main dewatering pipe to construct a seepage network covering different areas of the goaf.

[0015] In an optional embodiment, the pipe body of the dehydration pipeline assembly adopts a composite structure; the composite structure includes: The inner core plate, a skeleton structure made of pressure-resistant material, is used to keep the internal flow channels of the tube unobstructed; An external filter membrane is a filter medium that covers the outside of the inner core plate. The pore size of the external filter membrane is adapted to the particle size distribution of the filling slurry.

[0016] In an optional embodiment, the underground mining area filling and dewatering system further includes: A water-gas separation device is installed on the pipeline between the dehydration pipeline assembly and the negative pressure extraction device, and is used to separate the extracted fluid into gas and liquid.

[0017] In an optional implementation, the system further includes a co-boosting assembly; the co-boosting assembly includes: The reverse booster pipe is arranged independently of the dewatering pipeline assembly within the goaf area, and the pipe wall is provided with a microporous layer. A pressurization device is arranged outside the goaf and connected to the reverse pressurization pipe, and is used to inject pressurization medium into the reverse pressurization pipe.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: This method creates an active negative pressure seepage environment within the filling slurry by arranging dewatering pipelines and connecting them to a negative pressure extraction device inside the goaf. Utilizing the strong suction generated by the negative pressure, a significant pressure gradient is established between the pore water in the slurry and the interior of the pipelines, transforming the passive dewatering mode of traditional technology, which relies solely on gravity-driven natural seepage, into an active forced extraction mode. This mechanism effectively overcomes the capillary and pore resistance between fine-grained aggregates, significantly increasing the rate of water migration and discharge, thereby greatly improving the efficiency of dewatering in underground mining fillers and solving the problem of slow dewatering caused by insufficient driving force during the static or initial setting stages of the slurry in existing technologies.

[0019] Furthermore, this method can rapidly reduce the excess pore water pressure inside the slurry during or after the backfilling operation, accelerating the consolidation process of the backfill. By actively drawing water from the slurry into the pipeline and then draining it, the residence time of free water within the backfill is effectively reduced, promoting the formation of early strength in the backfill. This not only helps to shorten the backfill curing cycle but also significantly reduces the risk of excessive stress, leakage, or collapse of the backfill retaining wall caused by the accumulation of high hydrostatic pressure, thereby improving the safety of underground mining backfilling operations and the overall stability of the backfill. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram showing the structure and connection relationship of the underground mining area filling and dewatering system in the embodiments of this application; Figure 2 This is a front view of the interior of the goaf of the underground mining filling and dewatering system in this embodiment of the application; Figure 3 This is a cross-sectional schematic diagram of the pipeline of the dehydration pipeline assembly in the embodiments of this application.

[0022] Figure label: 100, Underground mining area filling and dewatering system; 1, Dewatering pipeline assembly; 11, Main dewatering pipe; 12, Auxiliary dewatering pipe; 13, Inner core plate; 14, External filter membrane; 2, Negative pressure extraction device; 3, Pipeline connectors; 4, Water-air separation device; 200, Goaf. Detailed Implementation

[0023] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0024] This application provides a method for controlled seepage drainage type underground mining site backfilling and dewatering, including: Step S1: Install a dewatering pipeline inside the goaf to be filled, and lead the water outlet of the dewatering pipeline to the outside of the goaf.

[0025] This step is fundamental to constructing the drainage network within the underground mining area. It involves installing and laying a pipeline system to collect and guide moisture in the empty space of the mining area (i.e., the goaf) before the backfilling operation begins. Importantly, this pipeline must have interfaces connecting the inside of the mining area to external areas (such as roadways, maintenance tunnels, and other safe zones), forming a connected physical passageway.

[0026] The principle is that by pre-installing pipelines inside the goaf, the limitations of traditional drainage that only occurs at the edge or bottom of the stope are changed, and the drainage channel is extended directly to the area that will be covered by the filling slurry in the future; and a low-resistance fluid transmission path is established, providing a more convenient "escape" channel for water in the subsequent slurry than through the dense slurry layer.

[0027] Specifically, regarding the location of the pipeline, it can be laid on the base plate, suspended below the roof plate, or fixed in the middle of the stope with supports, with the aim of maximizing the contact area with the main water accumulation zone of the slurry. As for the outlet method, the water outlet is usually led out through pre-reserved holes in the backfill retaining wall, and proper sealing is required to prevent slurry leakage. Furthermore, regarding the pipeline's shape, during implementation, the pipeline should have the characteristics of being permeable to water but impermeable to sand (e.g., with pores or gaps in the pipe wall) to allow water to enter the pipe.

[0028] Step S2: Connect the water outlet of the dewatering pipeline located outside the goaf to the negative pressure pumping device.

[0029] This step completes the physical connection between the "internal pipeline network" and the "external power source". The pipeline interfaces extending outside the goaf are then connected in an airtight manner to equipment capable of generating suction.

[0030] In this step, the complex mechanical and electrical equipment (negative pressure device) is placed in a safe environment outside the goaf, which facilitates the power supply, maintenance, and operation of the equipment, and prevents the equipment from being buried or damaged by the internal slurry. Through interconnection, a closed fluid suction system is constructed to ensure that the negative pressure generated subsequently can be transmitted to the pipelines inside the goaf without loss.

[0031] Specifically, flanges, quick couplings, or high-pressure resistant hoses can be used for connection, ensuring a tight seal at the connection to prevent air leakage that could lead to negative pressure failure. Regarding device selection, the negative pressure extraction device can be a vacuum pump, a centrifugal pump with a self-priming function, or a jet pump, as long as it can generate sufficient vacuum or negative pressure suction.

[0032] Step S3: Convey filling slurry into the goaf area.

[0033] This step is a standard operating procedure in backfill mining and also serves as the introduction process for the dewatering method. The prepared paste, high-concentration or low-concentration slurry, is transported to the goaf through backfill pipelines. As the slurry is introduced, it gradually submerges or envelops the pre-installed dewatering pipelines. At this point, the dewatering pipelines are surrounded by slurry with a high water content, and the outside of the pipelines is a medium rich in pore water, thus preparing the material for subsequent pumping.

[0034] Step S4: During or after the filling operation, the negative pressure extraction device is activated to create a negative pressure environment inside the dewatering pipeline. The negative pressure environment is used to establish a pressure difference between the filling slurry and the dewatering pipeline, drawing water from the filling slurry into the dewatering pipeline and discharging it to the outside of the goaf.

[0035] This step is the core of this method. By actively applying external force, the pressure distribution of the flow field is changed, forcing the migration of moisture.

[0036] The underlying principle is based on negative pressure seepage, specifically Darcy's law, which states that the seepage velocity of a liquid is directly proportional to the pressure gradient. Traditional methods rely solely on P... 自重 The hydrostatic pressure generated by the slurry's own weight serves as the driving force, resulting in a small pressure gradient. This method introduces P... 负压 (Vacuum level inside the tube) causes the total driving force to become ΔP = P 自重 +P 负压 Then, a pressure difference is established. After the device is started, the pressure inside the pipeline drops rapidly (below atmospheric pressure), while the pore water in the slurry outside the pipeline is under positive pressure (above or equal to atmospheric pressure). This huge internal and external pressure difference forcibly overcomes the capillary forces and viscous resistance between the slurry particles. Consequently, under the action of the pressure difference, water accelerates from the high-pressure zone (slurry pores) to the low-pressure zone (inside the dewatering pipeline) and is extracted into the pipe.

[0037] This method breaks the slow equilibrium of natural settling by gravity alone, achieving "forced dehydration." Rapid water removal effectively reduces the excess pore water pressure within the slurry, preventing slurry liquefaction or retaining wall damage caused by excessive pore water pressure. After water removal, the effective stress between solid particles increases, resulting in tighter particle contact and accelerating the consolidation and hardening process of the filling material.

[0038] The start-up timing includes: (1) "During filling": This allows for simultaneous filling and drainage, reducing the lateral pressure of the slurry on the retaining wall, and is suitable for high filling rates. (2) "After filling": This is mainly used to treat the static bleeding and deep water accumulation after filling, and to carry out the final consolidation and strengthening.

[0039] The control strategy involves adjusting the power or switching frequency of the negative pressure device to control the drainage speed, thus avoiding excessive fine particles (piping) carried away by excessively fast drainage or low efficiency due to excessively slow drainage.

[0040] In summary, this method establishes a pressure difference between the filling slurry and the dewatering pipeline by creating a negative pressure environment, thereby transforming passive gravity infiltration into active forced drainage. This significantly increases the driving force for water discharge, effectively overcomes pore resistance, and greatly improves dewatering efficiency. At the same time, this method can accelerate the dissipation of excess pore water pressure, promote rapid consolidation and early strength formation of the filling material, and effectively reduce hydrostatic pressure in the stope, thus significantly improving the stability and engineering safety of the filling material.

[0041] In some embodiments, step S1, which involves arranging dewatering pipelines inside the goaf to be filled, includes: Step S11: Construct a pipeline system consisting of a main dewatering pipe and several auxiliary dewatering pipes within the goaf area.

[0042] This step refines the single dehydration pipeline into a tiered system. The system consists of two parts: (1) The “main dewatering pipe” serves as the main manifold, responsible for transporting the collected water to the outside. (2) The “auxiliary dewatering pipe” serves as a water-absorbing branch pipe, responsible for directly penetrating the slurry to capture water.

[0043] It should be noted that the main pipe diameter is typically large to ensure sufficient flow capacity and vacuum transfer capability; the auxiliary pipes are numerous and widely distributed to increase the contact surface area with the slurry. The main pipe focuses on fluid transport and negative pressure distribution, while the auxiliary pipes focus on seepage induction and filtration collection. This design facilitates modular assembly and maintenance of the system.

[0044] Specifically, the main and auxiliary pipes can be connected using tee fittings, quick-connect fittings, or reducers to ensure airtightness and prevent negative pressure leakage.

[0045] Step S12: The main dewatering pipe is extended along the top plate or central area, and the auxiliary dewatering pipes are connected to the main dewatering pipe through joints, so that the auxiliary dewatering pipes extend into the internal space of the goaf to form a three-dimensional drainage network.

[0046] This method defines the spatial location of the manifold. It can be installed either above the goaf (roof) or suspended above the central axis, rather than at the bottom.

[0047] It should be noted that during the initial filling stage, the slurry accumulates from the bottom. Placing the main pipe at the top avoids direct impact and abrasion from the high-drop slurry during this initial stage, reducing the risk of damage. Securing the main pipe using anchor bolts or suspension devices on the stope roof provides more stable support compared to placing it on a loose floor, preventing displacement or breakage during slurry flow. The elevated location of the main pipe facilitates the formation of an upward suction gradient and allows for easy recovery after filling or use as a subsequent grouting channel.

[0048] The key to solving the problem of "low efficiency of planar dewatering" lies in extending the auxiliary dewatering pipe into the internal space of the goaf to form a three-dimensional drainage network. The auxiliary pipe is not laid flat on a two-dimensional plane, but rather extends into the three-dimensional volume of the goaf (i.e., the core area of ​​the filling body) like a tentacle.

[0049] Its principle is based on shortening the seepage path (an application of Darcy's Law). According to Darcy's Law, the seepage velocity is directly proportional to the hydraulic gradient and inversely proportional to the seepage path length. By inserting the auxiliary pipe into the space, the distance (L) between the water at any point in the slurry and the nearest drainage pipe (auxiliary pipe) is significantly shortened. Furthermore, it eliminates the "dehydration blind zone" in the central area caused by traditional edge drainage, ensuring that pore water throughout the filling material can be quickly captured.

[0050] In addition, the three-dimensional network allows the negative pressure field to be evenly distributed throughout the filling body, avoiding uneven internal stress caused by localized rapid dehydration while deep parts remain undehydrated.

[0051] Furthermore, the connection and arrangement of the plurality of auxiliary dehydration pipes shall follow the following rules: (1) Multiple rows of auxiliary dewatering pipes are arranged at intervals along the tunneling direction of the goaf.

[0052] The above rules are based on a discrete arrangement along the longitudinal (length direction). If the goaf is very long, it is not enough to arrange only one row of pipes; it is necessary to set up a set of auxiliary pipes at certain intervals along the length direction.

[0053] Specifically, for example, a branch water outlet is set up every 3 to 5 meters on the main pipe, and a row of auxiliary dewatering pipes is installed. This ensures the uniformity of dewatering throughout the entire length of the mining area and prevents water accumulation in areas far from the drainage point due to excessive filling length.

[0054] (2) Adjust the angle of each row of auxiliary dewatering pipes so that they are fan-shaped relative to the main dewatering pipes to cover different depths of the goaf.

[0055] The above configuration represents a spatial coverage strategy in the transverse (cross-sectional direction). On the same cross-section, multiple auxiliary pipes extend outwards at different angles from the main pipe, like fan ribs.

[0056] For example: one branch extends vertically downwards into the bottom, two branches extend diagonally downwards at a 45-degree angle into the middle, and two branches extend horizontally to the upper edge.

[0057] The principle lies in layered control, which involves adjusting the fan-shaped angle and pipe length to allow the auxiliary pipes to reach the bottom, middle, and top of the filling body respectively. It also includes targeted dewatering: bottom auxiliary pipes address the problem of poor drainage due to the solidification of the bottom slurry under its own weight; middle auxiliary pipes address the problem of water retention in the core area; and top auxiliary pipes address the drainage problem of the top bleeding layer.

[0058] This "fan-shaped" arrangement not only achieves full coverage of the cross-section, but also balances the dehydration rate in the vertical direction through pipelines at different angles, effectively suppressing the common "soft on top and hard on the bottom" segregation phenomenon in the filling body, and significantly improving the homogeneity of the entire filling body after consolidation.

[0059] In some embodiments, the dehydration pipeline is made of pipe with a composite structure. The composite structure includes a core plate as an internal support skeleton and a filter membrane covering the outside of the core plate.

[0060] The above-mentioned dehydration pipeline uses pipes with a composite structure (core plate + filter membrane), which means that the dehydration pipe is not an ordinary round pipe made of a single material, but a composite material composed of two layers of different functional materials, inner and outer.

[0061] The inner layer (core board) serves as a mechanical support unit and is typically a rigid or semi-rigid framework. The outer layer (filter membrane), as a functional filtration unit, is a flexible, permeable medium that covers the framework.

[0062] Its principle is based on the principle of mechanical support. In deep well filling, the self-weight and consolidation stress of the slurry are extremely high (potentially reaching several megapascals). Ordinary flexible pipes (such as spring tubes) are easily flattened, leading to the closure of the flow channel. The core plate, through its high compressive strength, forcibly opens a physical space under enormous lateral pressure, ensuring that the internal flow channel remains unobstructed. Furthermore, based on the principle of solid-liquid separation, the filter membrane utilizes its microporous structure and physical sieving to allow water molecules to pass through while intercepting tailings and cement particles, preventing solid materials from entering the pipe and causing siltation.

[0063] Its synergistic effect lies in the combination of rigidity and flexibility: the core board is responsible for "pressure resistance and collapse prevention," while the filter membrane is responsible for "water permeability and sand prevention." The combination of the two ensures both the existence of physical channels and the cleanliness of the channels.

[0064] The method further includes: Step S5: Before arranging the dewatering pipeline, select the filter membrane with a matching pore size according to the particle size distribution characteristics of the tailings and cementing materials in the filling slurry. The aforementioned step of "selecting a filter membrane with a matching pore size based on the particle size distribution characteristics of tailings and cementing materials in the filling slurry" is a preliminary "process design" step. This means that before pipe installation, the filling slurry must be sampled and analyzed to determine its particle size distribution (e.g., dp). 10 ,d 50 ,d 90 Based on the characteristic particle size, the pore size parameters of the filter membrane are selected.

[0065] It should be noted that if the pore size of the filter membrane is too large, fine cement particles and tailings will penetrate the filter membrane and enter the pipe, causing "piping" or siltation inside the pipe; if the pore size is too small, although the barrier effect is good, the water permeation resistance increases dramatically and it is easily blocked by extremely fine particles ("siltation").

[0066] In this method, in order to ensure that the dewatering pipeline can both efficiently permeate water and effectively prevent solid particles in the filling slurry from entering the pipeline and causing siltation, a filter membrane pore size matching method based on particle size distribution analysis is adopted in this embodiment.

[0067] Specifically, before arranging the dewatering pipeline, laser particle size analysis is first performed on the solid particles of the slurry to be filled (including tailings and cementing materials) to determine its characteristic particle size parameters, including d10, d50, d85, etc. (where dx represents x% of the total mass of particles smaller than this particle size). To achieve the best balance between clogging prevention and permeability, according to a preferred embodiment of the present invention, a filter membrane (typically geotextile or stainless steel sintered mesh) with an equivalent pore size (O95) satisfying the following empirical formula is selected: O 95 ≤α×d 85 ; In the formula, α is the anti-clogging coefficient, which typically ranges from 1.0 to 2.5. When the slurry contains a high content of fine particles (such as ultra-fine tailings backfilling), α should be a smaller value (1.0 to 1.5) to enhance the interception effect; when the slurry contains a high content of coarse particles (such as graded tailings backfilling), α can be a larger value (1.5 to 2.5) to reduce the seepage resistance.

[0068] In practical engineering applications, those skilled in the art can quickly select the filter membrane for the dehydration pipeline based on the above guiding principles and with reference to the preferred correspondence shown in Table 1 below: The table below lists the recommended filter membrane specifications for different types of filling slurries: Table 1. Recommended Filter Membrane Specifications for Different Types of Filling Slurries

[0069] As a specific selection example (as described in Example 2 below), when using a full tailings cemented backfill slurry with a characteristic particle size d85 of approximately 120 μm, referring to the above rules, a 200-mesh external filter membrane with a suitable pore size is selected, which can exhibit excellent anti-clogging effect in subsequent intermittent pumping.

[0070] Furthermore, in step S4, the step of activating the negative pressure extraction device adopts an intermittent extraction process: Step S41: Control the negative pressure extraction device to periodically open and close, or periodically adjust the suction pressure; Step S42: By utilizing the periodic changes in the internal pressure of the dewatering pipeline, the filter membrane is driven to undergo micro-motion deformation relative to the core plate, so as to peel off or loosen the filling slurry particles adsorbed on the surface of the filter membrane.

[0071] In this method, in order to overcome the problem that a dense filter cake layer is easily formed on the surface of the filter membrane during the traditional continuous negative pressure extraction process, resulting in a sharp drop in permeation flux, an "intermittent pulse extraction" control strategy is adopted. By periodically adjusting the working state of the negative pressure extraction device, the active self-cleaning of the filter membrane surface is achieved by utilizing the pressure fluctuation inside the dehydration pipeline.

[0072] For example, a specific process may include the following: (1) Negative pressure adsorption stage (working phase): The negative pressure extraction device is started to quickly establish a high negative pressure environment inside the dewatering pipeline. The vacuum degree is usually maintained at -0.06MPa to -0.09MPa (relative to standard atmospheric pressure). In this stage, the flexible filter membrane adheres tightly to the surface of the internal rigid core plate under the combined action of the external slurry pressure and the internal negative pressure, and exhibits an inward contraction state. At this time, the pore water in the slurry is driven by the pressure difference to pass through the filter membrane and enter the pipe to be extracted. At the same time, the solid particles in the slurry are trapped on the surface of the filter membrane and gradually form a filter cake layer.

[0073] (2) Pressure release / recovery phase (relaxation phase): After the working phase lasts for a certain period of time (e.g., T1 = 10 to 30 minutes), the negative pressure extraction device is stopped or the extraction power is reduced to rapidly reduce or restore the negative pressure inside the pipeline to near normal pressure (e.g., -0.01 MPa to 0 MPa), with a duration of T2 = 2 to 5 minutes. During this phase, as the internal and external pressure difference decreases or disappears, the filter membrane utilizes its own material elasticity or memory to spring back or relax relative to the core plate, resulting in slight mechanical deformation.

[0074] (3) Filter cake peeling and regeneration: The above "adsorption-relaxation" process is carried out in a cyclical manner (i.e., T cycle=T1+T2). This periodic micro-motion deformation on the filter membrane surface can disrupt the structural integrity of the filter cake layer, causing it to crack, loosen, or even partially detach, thereby restoring the permeable pores of the filter membrane and preventing excessive accumulation and caking of fine particles. In addition, the brief pauses also facilitate the redistribution and aggregation of moisture within the slurry.

[0075] The time cycle parameters (e.g., working phase lasts 10-30 minutes, relaxation phase lasts 2-5 minutes) and pressure fluctuation range (e.g., from -0.06MPa to -0.09MPa back to near atmospheric pressure) of the above-mentioned intermittent pumping process are key to achieving efficient anti-clogging.

[0076] The underlying mechanism is as follows: although intermittent operation reduces the absolute suction time, the specific periodic parameters mentioned above precisely match the mechanical response time of the filter membrane's micro-rebound in the composite pipe. If the working phase time is too long, the filter cake layer will be over-compacted and difficult to peel off; if the relaxation phase time is too short, the filter membrane cannot achieve sufficient elastic rebound. Through periodic control of the above parameter range, the effective rebound of the filter membrane during shutdown can completely destroy the structural integrity of the filter cake layer, not only preventing irreversible deep clogging but also allowing the initial permeation flux of each subsequent working phase to be fully restored.

[0077] Therefore, as verified by the comparative experiments (Table 2) below, compared with the continuous pumping process that causes a sharp decrease in flow rate due to rapid blockage, the intermittent operation with the above-mentioned specific parameters of the present invention can maintain a high average permeability throughout the entire filling and curing cycle, and the total drainage efficiency is increased by 20% to 40%, and the service life of the dewatering pipeline is significantly extended.

[0078] In some embodiments, step S2, connecting the water outlet of the dewatering pipeline located outside the goaf to the negative pressure pumping device, further includes: Step S21: Connect a water-air separator in series between the dehydration pipeline and the negative pressure extraction device.

[0079] This step defines the connection topology of the pipeline. The outlet of the dewatering pipeline is not directly connected to the air inlet of the vacuum pump (negative pressure extraction device), but is first connected to an intermediate container: a "water-air separation device" (such as a gas-water separator, water collection tank, etc.), and then the air outlet of this device is connected to the vacuum pump. That is: goaf area → dewatering pipe → separation device → vacuum pump.

[0080] It should be noted that conventional high-vacuum negative pressure equipment (such as rotary vane vacuum pumps) is designed for pumping air and is very sensitive to liquid water. If water containing sand enters the pump body directly, it can cause lubricating oil emulsification, component corrosion, and even "liquid hammer" damage to the equipment. The separation device, acting as a buffer volume, can smooth out instantaneous pressure fluctuations in the pipeline, making the vacuum pump's load more stable.

[0081] Specifically, it can be a sealed metal or pressure-resistant plastic tank. The tank is equipped with a water inlet (connected to the dewatering pipe), an air outlet (located at the top, connected to the vacuum pump), and a drain outlet (located at the bottom). The installation location can be placed on a stable surface outside the goaf, before the vacuum pump, and the position is preferably lower than the outlet of the dewatering pipe to facilitate gravity-assisted water collection.

[0082] In step S22, the fluid extracted from the goaf first enters the water-gas separation device for gas-liquid separation. The separated gas is extracted by the negative pressure extraction device, and the separated liquid is retained in the water-gas separation device or discharged separately.

[0083] This method describes the fluid treatment process within the device. The fluid extracted from the goaf is often a "gas-water mixture" (containing pore water and air). This step uses physical methods to separate these two phases and treat them separately.

[0084] In this process, the flow rate of the mixed fluid decreases sharply after entering the large-volume separation tank through a thin tube. Since water is much denser than air, water droplets and entrained fine particles settle to the bottom of the tank under gravity, while the lighter gas rises to the top. Furthermore, by installing baffles inside the tank or using tangential cyclone air intake, centrifugal force and inertia are used to cause water droplets to collide with the walls and converge, further improving separation efficiency.

[0085] The vacuum pump only extracts gas from the top, ensuring it always operates under designed conditions, maintaining a high level of vacuum and extending equipment life. The water remaining in the tank can be collected and measured. By observing changes in the collected water volume, staff can visually assess the dewatering progress within the mining area (e.g., a significant decrease in water output per unit time may indicate that dewatering is nearing completion or that pipeline maintenance is needed to prevent blockages).

[0086] In addition, for small systems or systems with low water output, water accumulates at the bottom of the tank and is manually drained through a bottom valve once a certain level is reached. For systems with high water output, an automatic drain pump or one-way drain valve can be installed at the bottom of the separator. When the level sensor detects a high water level, the drain pump automatically starts to discharge the water into the mine drainage ditch, enabling unattended continuous operation.

[0087] In some embodiments, the controlled seepage drainage underground mining filling and dewatering method further includes step S6, a coordinated pressurization step.

[0088] In this method, in order to further solve the problem of dehydration in deep blind areas that are difficult to reach by relying solely on negative pressure pumping in deep wells and high-density mining areas, as well as the problem of water being difficult to drain in the lower part of the filling body due to stress concentration, this embodiment introduces a positive and negative pressure coordinated control strategy based on the above-mentioned negative pressure pumping method.

[0089] Step S61: A reverse booster pipe, independent of the dewatering pipeline, is pre-arranged inside the goaf; the reverse booster pipe is arranged inside or in the lower middle part of the goaf filling body.

[0090] This step involves the independent arrangement of the reverse booster pipe, which means that a reverse booster pipe, independent of the dewatering pipeline system, is pre-installed inside the goaf.

[0091] The reverse booster pipe is mainly located inside the filling body of the goaf or in the middle and lower part of the goaf (i.e., the area away from the top main dewatering pipe). For example, it can be laid on the bottom plate of the stope or suspended at the middle and lower height of the stope. Its specific position should form a spatial counter-pull relationship with the upper dewatering pipeline.

[0092] The reverse booster pipe is not connected to the dewatering pipeline inside the mining area, but serves as an independent pressure input channel, with its air inlet leading out to the outside of the goaf.

[0093] Step S62: During the operation of the negative pressure extraction device, compressed gas or pressurizing medium is injected into the reverse pressurization pipe.

[0094] During this step, while the negative pressure extraction device is in operation (including synchronous operation or independent operation in the later stage of dehydration), the air inlet end of the reverse booster pipe located outside the goaf is connected to an external booster device (such as an air compressor or high-pressure pump), and compressed gas (such as compressed air or inert gas) or liquid booster medium is injected into the pipe.

[0095] For example, the pressure of the injected medium can be controlled within the range of 0.2MPa to 0.6MPa (adjusted according to the filling depth and slurry characteristics) to ensure that the medium can overcome the pore resistance of the slurry and enter the interior of the filling body, while avoiding excessive pressure that could cause damage to the filling body structure or instability of the retaining wall.

[0096] Step S63: Using the negative pressure suction at the dewatering pipeline and the positive pressure at the reverse pressurization pipe, a directional pressure gradient is formed inside the filling slurry; In this step, a strong, directional pressure gradient field is constructed inside the filling slurry by utilizing the negative pressure suction (e.g., -0.06MPa to -0.09MPa) generated at the dewatering pipeline and the positive thrust (e.g., +0.2MPa or more) generated at the reverse pressurization pipe.

[0097] It should be noted that, under the combined action of the displacement (push) of the high-pressure gas and the suction (pull) of the negative pressure pipeline, the water that was originally stuck in the deep or tiny pores is forcibly driven and accelerates to converge and be discharged from the dehydration pipeline along the designed path (from bottom to top, from the center to the surroundings).

[0098] The introduction of gas can also change the viscosity characteristics of local fluids, disrupt capillary action, and promote the transformation of fine particles from a suspended state to a closely contacted skeletal structure, thereby significantly shortening the consolidation time of the filling and improving its early strength.

[0099] Furthermore, the selection of the reverse booster tube follows these rules: A permeable pipe with a microporous layer in its wall and overall deformability is selected as the reverse booster pipe; the microporous layer is used to prevent solid particles from entering the pipe, and the deformability is used to make the reverse booster pipe shrink or recover under external pressure changes to adapt to the deformation of the filling material.

[0100] To complement the aforementioned pressurization process and ensure the long-term reliability of the pipeline under harsh operating conditions, the reverse pressurization pipe is selected from a permeable pipe with microporous filtration function and overall deformable characteristics (such as a high-strength microporous rubber pipe, a microporous corrugated pipe with an inner spring lining, etc.).

[0101] It should be noted that the micron-sized pores distributed on the pipe wall (the pore size is usually smaller than the particle size of the slurry) allow high-pressure gas molecules to diffuse outward in one direction into the slurry, but can effectively prevent tailings and cement particles in the slurry from flowing back into the pipe, thus preventing the pipeline from becoming blocked when the gas supply is stopped.

[0102] In this method, based on a dynamic deformation mechanism ("breathing" anti-clogging), the elasticity or flexibility of the pipe material is utilized to enable it to "breathe". When a high-pressure medium is injected, the pipe expands under internal pressure, the micropores open, and the airflow is ejected to disperse surrounding particles that are trying to adhere; when the gas injection stops or the external slurry solidifies and shrinks, the pipe contracts under external pressure or deforms synchronously with the filling material, the micropores close and cut off the return path, and avoid pipe breakage or cracking of the surrounding slurry due to rigid resistance.

[0103] This application also provides an underground mining area filling and dewatering system for implementing the controlled seepage drainage underground mining area filling and dewatering method as described in the foregoing embodiments.

[0104] The underground mining area filling and dewatering system includes: a dewatering pipeline assembly configured to be arranged inside the goaf to be filled, for collecting moisture from the filling slurry in the goaf; a negative pressure extraction device configured to be arranged outside the goaf and having a power mechanism for generating negative pressure suction; and a pipeline connector for connecting the water outlet of the dewatering pipeline assembly to the air inlet of the negative pressure extraction device; when the negative pressure extraction device is activated, a negative pressure environment is formed inside the dewatering pipeline assembly to drive moisture from the filling slurry into the dewatering pipeline assembly.

[0105] The aforementioned dewatering pipeline assembly is the system's "end-point actuator" or "sensing antennae." It refers to the collective term for all pipelines arranged within the goaf that directly contact the filling slurry and collect moisture. The term "assembly" indicates not just a single pipe, but a combination of multiple pipes, joints, end caps, etc. (i.e., the aforementioned main and auxiliary pipe network). This assembly is designed to be pre-embedded or suspended within the goaf space before filling.

[0106] Compared to traditional flat pipes that are only laid at the bottom, this component can penetrate deep into the three-dimensional space of the mining area.

[0107] The component employs a pressure-resistant structure (such as a composite tube) suitable for negative pressure environments to prevent it from collapsing under high vacuum.

[0108] This component solves the problems of traditional drainage facilities having small coverage and being easily buried and failing, ensuring comprehensive capture of moisture in the slurry.

[0109] The dehydration pipeline components can be made of high-density polyethylene (HDPE), PVC, or steel wire reinforced composite pipes, and must have corrosion resistance and wear resistance.

[0110] For example, the main pipe diameter is DN100-DN150, and the auxiliary pipe diameter is DN50-DN80, connected by a tee or cross connector.

[0111] The aforementioned negative pressure extraction device is the "power heart" of the system, referring to mechanical equipment installed outside the mining area (such as in roadways or chambers) that can continuously generate and maintain a certain degree of vacuum or negative pressure suction. The "power mechanism" refers to the electric motor or internal combustion engine that drives the pump.

[0112] The dehydration power source can be transformed from uncontrollable "gravity" to controllable "mechanical force". The motor speed can be adjusted by a frequency converter, thereby changing the magnitude of the suction negative pressure to meet the needs of different filling stages (such as initial fast discharge and later slow discharge).

[0113] This device solves the problems of low efficiency and susceptibility to interruption caused by natural osmosis dehydration.

[0114] Specifically, water ring vacuum pumps (suitable for pumping water-containing gases), Roots vacuum pumps (suitable for high flow rates), or jet pumps (which utilize high-pressure water / gas to generate negative pressure and have a simple structure) can be used. The maximum vacuum level can reach -0.09 MPa, and the pumping rate is calculated and determined based on the stope volume and expected water seepage, typically ranging from 5 to 50 m³ / h. 3 Within the range of / min.

[0115] The aforementioned pipeline connectors act as a bridge connecting the "inside" and the "outside." They refer to all pipe fittings, valves, and sealing interfaces that physically connect the water outlet of the dewatering pipeline located inside the goaf to the air inlet of the negative pressure device located outside. These connectors are not only fluid channels but also airtight barriers, ensuring no leakage under negative pressure.

[0116] The pipe connectors effectively address the sealing issue where pipes pass through the filling retaining wall. They also facilitate quick disassembly of external equipment after filling, allowing for easy reuse.

[0117] Its structure may include a through-wall sleeve, a check valve (to prevent backflow during shutdown), a manual / electric ball valve (for shutting off the pipeline), and a flexible joint (for absorbing equipment vibration). It is usually located on the outside of the filling retaining wall for easy access and maintenance by operators.

[0118] In the above system, upon startup, the device operates → the connector transmits suction → the internal pressure of the components decreases → P is formed. 管内 <P 大气 The environment.

[0119] Its driving mechanism includes: utilizing P 料浆 -P 管内 The huge pressure difference forcibly "sucks" pore water into the pipe.

[0120] In some embodiments, the dewatering pipeline assembly includes: a main dewatering pipe for extending along the direction of the goaf; and a plurality of auxiliary dewatering pipes connected to the main dewatering pipe via joints and distributed in a three-dimensional divergent manner relative to the main dewatering pipe to construct a seepage network covering different areas of the goaf.

[0121] In order to overcome the problem that existing dewatering pipelines are mostly arranged in two-dimensional planar or peripheral layouts, resulting in a large number of dewatering blind spots in the deep and central areas of the mining area, the dewatering pipeline component in this embodiment adopts a hierarchical three-dimensional network structure of "main trunk-branch".

[0122] In the aforementioned dewatering pipeline assembly, the main dewatering pipe (manifold) is arranged as follows: the main dewatering pipe extends along the direction (i.e., the length direction) of the goaf to be filled. Preferably, it is suspended and fixed below the goaf roof using hangers, or fixed to the central axis area of ​​the goaf cross-section using a support frame, serving as the main negative pressure transmission channel and water collection main pipe for the entire seepage system.

[0123] The main dewatering pipe can be made of rigid or semi-rigid pipe with high negative pressure resistance (such as HDPE pipe or steel-plastic composite pipe), and the pipe diameter can be DN100 to DN150 to ensure sufficient flow cross-section and reduce friction loss.

[0124] The connection relationship of the above-mentioned auxiliary dewatering pipe (suction branch pipe) can be as follows: several diversion nodes are set at intervals along the axial direction of the main dewatering pipe, and at each diversion node, a set (e.g., 3 to 6) of auxiliary dewatering pipes are connected by a reducing tee, cross or multi-way connector.

[0125] The auxiliary dewatering pipes extend from the main dewatering pipe to different spatial directions in the goaf, forming a three-dimensional, radiating distribution. Specifically, they may include: (1) vertical auxiliary pipes: some auxiliary dewatering pipes extend vertically or nearly vertically downwards, penetrating deep into the bottom and central areas of the goaf; (2) oblique auxiliary pipes: some auxiliary dewatering pipes extend obliquely downwards (for example, at an angle of 30° to 60° with the vertical direction), covering the central and lower side areas of the goaf; (3) horizontal auxiliary pipes: some auxiliary dewatering pipes extend horizontally or nearly horizontally to both sides, covering the upper and edge areas of the goaf.

[0126] Through the above structural design, the main dewatering pipe and multiple auxiliary dewatering pipes together construct a three-dimensional seepage network resembling "plant roots" or "fishbone". This network structure spatially divides the massive goaf volume into several tiny seepage units, significantly shortening the distance between any point of water in the filling slurry and the nearest dewatering pipe wall (seepage path). This macroscopically eliminates dewatering blind spots and achieves uniform and efficient dewatering of the entire cross-section and depth of the goaf.

[0127] In some embodiments, the pipe body of the dehydration piping assembly adopts a composite structure; the composite structure includes: The inner core plate, a skeleton structure made of pressure-resistant material, is used to keep the internal flow channels of the tube unobstructed; An external filter membrane is a filter medium that covers the outside of the inner core plate. The pore size of the external filter membrane is adapted to the particle size distribution of the filling slurry.

[0128] In this embodiment, in order to solve the problems in the prior art that flexible dewatering pipes are prone to collapse and deformation under the high confining pressure environment of deep well filling, resulting in blockage of the drainage path, and that the filter medium is easily blocked by fine cement particles, the dewatering pipeline assembly (including the main dewatering pipe and / or the auxiliary dewatering pipe) in this embodiment adopts a special composite structure of "inner skeleton + outer filter layer".

[0129] Specifically, the composite structure is composed of an inner core plate and an outer filter membrane tightly bonded together.

[0130] The aforementioned inner core plate serves as a compressive support framework, acting as the mechanical support unit for the tube. It is preferably made of materials with high compressive strength and good corrosion resistance, such as high-density polyethylene (HDPE), polyvinyl chloride (PVC), stainless steel, or high-strength composite materials. In terms of shape, the inner core plate can be designed as a porous circular tube, a spiral skeleton, or a strip with a cross / star-shaped cross-section.

[0131] The main function of the inner core plate is to resist the enormous lateral earth pressure and self-weight stress generated by the filling slurry, preventing radial collapse or closure of the pipe under deep burial conditions, thereby always maintaining a smooth fluid transport channel (i.e., an effective flow cross-section) inside the pipe. At the same time, the surface of the inner core plate is designed with guide grooves or permeable holes to guide the water passing through the filter membrane smoothly into the pipe.

[0132] The aforementioned external filter membrane is a fine filtration medium. It is a flexible, permeable medium that covers the outside of the inner core plate. Preferred materials include geotextile (non-woven fabric), nylon filter mesh, or stainless steel sintered mesh.

[0133] The pore size of the external filter membrane is not chosen arbitrarily, but is strictly adapted to the particle size distribution characteristics of the filling slurry. Specifically, the equivalent pore size (O) of the external filter membrane is... 95 It should be slightly smaller than the key characteristic particle size of the skeleton particles (tailings) in the slurry (e.g., d). 85 ).

[0134] External filter membranes can effectively intercept tailings particles and cementitious solids in the slurry, preventing them from entering the pipe and causing siltation; they utilize microporous structures to allow pore water to pass freely; and in the initial stage of negative pressure pumping, they induce fine particles to form a stable "soil skeleton" or "reverse filter layer" on the membrane surface, thereby achieving finer filtration using the slurry itself.

[0135] This composite structural design, combining rigidity and flexibility, resolves the contradiction between high pressure resistance and high permeability inherent in single-material pipes: relying on the rigidity of the inner core plate, the dehydration channels remain open even in high-pressure environments hundreds of meters deep underground. Combined with the aforementioned intermittent negative pressure extraction process, the flexible outer filter membrane can undergo slight adsorption-rebound deformation relative to the rigid inner core plate under changes in negative pressure. This differential deformation effectively peels off the filter cake layer adhering to the membrane surface, achieving active self-cleaning of the pipeline and fundamentally solving the engineering problems of easy clogging and short lifespan of traditional filter tubes.

[0136] In some embodiments, the underground mining area filling and dehydration system further includes a water-gas separation device, which is installed on the pipeline between the dehydration pipeline assembly and the negative pressure extraction device, for gas-liquid separation of the extracted fluid.

[0137] In this embodiment, in order to ensure the long-term stable operation of the dehydration system and further improve the processing capacity for deep, difficult-to-dehydrate areas in the mining area, the underground mining area filling dehydration system described in this embodiment also includes a water-gas separation device and a collaborative pressurization component.

[0138] The aforementioned water-gas separation device can adopt a sealed tank structure (such as a gas-water separation tank, a water collection tank, etc.), and its volume is designed to match the estimated amount of water seepage from the mining area and the pumping rate.

[0139] The device is connected in series on the pipeline between the dehydration pipeline assembly (water outlet) and the negative pressure extraction device (air inlet). Specifically, the separation device has a liquid inlet, an exhaust outlet, and a liquid outlet. The fluid from the dehydration pipeline enters the tank through the liquid inlet, the exhaust outlet is usually located at the top of the tank and connected to the negative pressure extraction device, and the liquid outlet is located at the bottom of the tank.

[0140] It should be noted that the fluid extracted from the goaf is typically a multiphase flow consisting of a mixture of gas, water, and fine particles. When this mixed fluid enters a large-volume separation device, its velocity decreases sharply. Utilizing the principle of gravity settling, the denser liquid water and solid particles fall to the bottom of the tank, while the less dense gas rises to the top.

[0141] After separation, only the pure gas is extracted by the negative pressure extraction device (such as a vacuum pump), while the liquid water remains in the device. This process effectively prevents moisture from directly entering the vacuum pump cavity, avoiding lubricant emulsification, component corrosion, or "liquid slugging," and significantly extending the lifespan of the core equipment.

[0142] Furthermore, the dehydration efficiency can be directly monitored by observing changes in the liquid level within the separation device. The separated liquid can be manually discharged periodically through the bottom valve, or continuously discharged using an automatic drain pump.

[0143] In some embodiments, the system further includes a co-pressurization assembly; the co-pressurization assembly includes: a reverse pressurization pipe, arranged independently of the dewatering pipeline assembly within the goaf, with a microporous layer on the pipe wall; and a pressurization device, arranged outside the goaf and connected to the reverse pressurization pipe, for injecting a pressurizing medium into the reverse pressurization pipe.

[0144] The aforementioned reverse booster pipe is a pipeline system independent of the dewatering pipeline assembly. It is located inside the filling material of the goaf, preferably in the lower or middle section or in deep, hard-to-reach areas that the dewatering pipeline cannot cover. This pipeline does not participate in pumping; it is specifically used for inputting pressurized media.

[0145] The aforementioned booster device is located outside the goaf, at a power source such as an air compressor, high-pressure grouting pump, or inert gas cylinder. It is connected to the air inlet of the reverse booster pipe via a high-pressure hose or metal pipe.

[0146] The reverse booster pipe has a microporous layer (e.g., laser-drilled or made of porous breathable material) on its wall. The pore size is designed to allow gas or fluid media to permeate outward in one direction only, while preventing backflow of external slurry particles.

[0147] High-strength flexible hoses (such as rubber composite hoses) are preferred. When high-pressure media are injected, the hose expands, the micropores open, and jetting occurs; when injection stops, the hose retracts, and the micropores close. This "breathing" deformation characteristic prevents pipe blockage and adapts to the settlement deformation of the filling material, avoiding rigid breakage.

[0148] It should be noted that while the negative pressure extraction device generates suction at the top of the stope, the pressurization device is activated to inject compressed gas (or pressurized water) into the reverse pressurization pipe at the bottom. Inside the filling slurry, the positive pressure at the bottom and the negative pressure at the top superimpose, forming a significant directional pressure gradient. This not only forces deep moisture to migrate upwards to the dewatering pipeline, but also disrupts capillary resistance through gas disturbance, accelerating the transformation of the filling material from a fluid to a solid state, significantly improving dewatering efficiency and the early strength of the filling material.

[0149] To further verify the actual technical effect of the controllable seepage drainage underground mining filling and dewatering method and system provided in this application, the following provides several embodiments and comparative examples with existing technologies, based on specific engineering simulation experiments, to illustrate the effects.

[0150] Experimental conditions: This experiment was conducted in a simulated underground mining void (20m long × 15m wide × 30m high). The filling slurry used was a fully cemented tailings filling slurry with an initial mass concentration of 70% and a cement-to-sand ratio of 1:6. The characteristic particle size d of the tailings in the slurry was... 85 It is approximately 120 μm.

[0151] Comparative Example 1 (Traditional Gravity Natural Drainage) This comparative example simulates the passive dewatering method in existing technologies. A traditional single-layer flexible filter hose is laid at the bottom of the stope and inside the backfill retaining wall. After the backfill slurry is transported, without applying any external power, water is naturally infiltrated and discharged through the filter hose solely by the weight of the backfill slurry and hydrostatic pressure.

[0152] Comparative Example 2 (Continuous negative pressure extraction - uninterrupted anti-clogging process) This comparative example, based on Comparative Example 1, extends a dehydration pipeline connected to an external vacuum pump. The pipeline uses a standard single-layer filter screen. After starting the vacuum pump, the negative pressure inside the pipeline is maintained at -0.08 MPa for continuous, uninterrupted pumping.

[0153] Example 1 (Three-dimensional drainage network + foundation negative pressure drainage) This embodiment employs the method described in claims 1 and 2 of this invention. A three-dimensional "main trunk-branch" pipe network is constructed within the goaf. The main dewatering pipe (DN150) is fixed to the center of the goaf roof, and a set of auxiliary dewatering pipes (DN50) is installed every 4 meters. Each set of auxiliary dewatering pipes extends in a fan shape, vertically downward, obliquely downward, and horizontally, covering different depths of the goaf. The auxiliary pipes are made of composite pipes wrapped with geotextile. After filling is completed, a negative pressure drainage device is activated to maintain a negative pressure of -0.08 MPa for drainage.

[0154] Example 2 (Composite pipe + intermittent pulse anti-clogging and drainage) This embodiment employs the method described in claim 3 of the present invention. Based on embodiment 1, the auxiliary dehydration pipe strictly adopts a composite structure of "high-strength PE inner core board + 200-mesh outer filter membrane". When the negative pressure extraction device is started, an intermittent extraction process is used for control: the extraction cycle is set to 25 minutes, of which the working phase (suction, negative pressure maintained at -0.08MPa) lasts for 20 minutes; the relaxation phase (shutdown release, negative pressure restored to 0MPa) lasts for 5 minutes. The dehydration operation is carried out in a cyclical manner.

[0155] Example 3 (Positive and negative pressure coordinated pressurization and extraction) This embodiment employs the advanced method described in claim 5 of this invention. Based on embodiment 2, a reverse-pressure boosting rubber tube with a microporous layer and deformable properties is additionally and independently laid on the bottom plate (lower middle region) of the stope. During the intermittent pumping operation of the top negative pressure pumping device, compressed air at a pressure of 0.3 MPa is continuously injected into the bottom reverse-pressure boosting tube simultaneously, forming a directional pressure gradient of "upward suction and downward push" within the slurry.

[0156] Test experiments and results analysis: 1. Testing method: The above embodiments and comparative examples were monitored for filling and dehydration for 72 hours. The main findings were "cumulative dehydration volume", "flow rate attenuation after 48 hours (reflecting the blockage)" and "bottom uniaxial compressive strength of the filling body after 3 days of curing (reflecting the deep consolidation effect)".

[0157] 2. The test results are shown in the table below: Table 2. Comparison of Filling and Dehydration Effect Tests

[0158] 3. Analysis: (1) Regarding dehydration efficiency and driving force, comparing Example 1 and Comparative Example 1, it can be seen that after introducing negative pressure to establish a pressure difference, the cumulative dehydration volume in 72 hours increased from 125m³. 3 Significantly increased to 385m 3 The dehydration efficiency was increased by more than 2 times. This fully demonstrates that the "active forced pumping" of this invention has an overwhelming efficiency advantage over "passive gravity drive" and overcomes the defect of insufficient dehydration power.

[0159] (2) Regarding the anti-clogging mechanism, comparing Example 2 and Comparative Example 2, it can be seen that although the traditional continuous pumping (Comparative Example 2) has a large initial water volume, the filter screen is easily clogged by fine cement particles, and the flow rate decay rate is as high as 85.5% after 48 hours, resulting in the system's basic failure. In contrast, Example 2 uses composite pipes combined with an intermittent micro-motion deformation process of "20 minutes on, 5 minutes off," which effectively peels off the filter cake layer, with a flow rate decay rate of only 12.5%, maintaining a long-term permeation flux, and the total dewatering volume surpasses that of the continuous pumping group. This strongly supports the effectiveness of the anti-clogging mechanism of this invention.

[0160] (3) Regarding the synergistic effect of deep consolidation and pressurization, compared with other groups, it can be seen that by creating a "push-pull effect" through bottom reverse air injection and top negative pressure, the total dehydration volume is further increased to 510m³. 3 More importantly, it solved the problem of deep dewatering, with the early compressive strength at the bottom of the filling reaching 3.2 MPa after 3 days, far exceeding the 0.8 MPa of natural drainage. This proves that the three-dimensional layout and synergistic pressurization function of this system completely eliminates the dewatering blind zone and significantly improves the homogeneity and mechanical stability of the filling.

[0161] In summary, the controllable seepage drainage dewatering method and system provided in this application effectively solves the three major engineering problems of low dewatering efficiency, blind spots in deep areas, and easy clogging of filter channels in the prior art. It has significant practical value and broad prospects for promotion in mines.

[0162] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A controlled seepage drainage method for filling and dewatering underground mining areas, characterized in that, include: A dewatering pipeline is installed inside the goaf to be filled, and the outlet of the dewatering pipeline is led out to the outside of the goaf. Connect the water outlet of the dewatering pipeline located outside the goaf to the negative pressure pumping device; The filling slurry is delivered into the goaf. During or after the filling operation, the negative pressure extraction device is activated to create a negative pressure environment inside the dewatering pipeline. The negative pressure environment is used to establish a pressure difference between the filling slurry and the dewatering pipeline, drawing water from the filling slurry into the dewatering pipeline and discharging it to the outside of the goaf.

2. The controlled seepage drainage method for filling and dewatering underground mining areas as described in claim 1, characterized in that, The installation of dewatering pipelines within the goaf to be filled includes: A pipeline system consisting of a main dewatering pipe and several auxiliary dewatering pipes is constructed within the goaf area; The main dewatering pipe is extended along the top plate or central area, and the auxiliary dewatering pipes are connected to the main dewatering pipe through joints, so that the auxiliary dewatering pipes extend into the internal space of the goaf to form a three-dimensional drainage network. Preferably, the connection and arrangement of the plurality of auxiliary dehydration pipes follow the following rules: Multiple rows of auxiliary dewatering pipes are arranged at intervals along the tunneling direction of the goaf. Adjust the angle of each row of auxiliary dewatering pipes so that they fan out relative to the main dewatering pipes to cover different depth levels of the goaf.

3. The controlled seepage drainage method for filling and dewatering underground mining areas as described in claim 1, characterized in that, The dehydration pipeline is made of pipe with a composite structure; the composite structure includes a core plate as an internal support skeleton and a filter membrane covering the outside of the core plate; The method further includes: Before arranging the dewatering pipeline, the filter membrane with a matching pore size is selected based on the particle size distribution characteristics of the tailings and cementing materials in the filling slurry. Preferably, the step of activating the negative pressure extraction device adopts an intermittent extraction process: The negative pressure extraction device is controlled to periodically open and close, or the suction pressure is periodically adjusted; The periodic changes in pressure inside the dewatering pipeline drive the filter membrane to undergo micro-deformation relative to the core plate, thereby peeling off or loosening the filling slurry particles adsorbed on the surface of the filter membrane.

4. The controlled seepage drainage method for filling and dewatering underground mining areas as described in claim 1, characterized in that, The step of connecting the water outlet of the dewatering pipeline located outside the goaf area to the negative pressure pumping device further includes: A water-air separator is connected in series between the dehydration pipeline and the negative pressure extraction device. The fluid extracted from the goaf first enters the water-gas separation device for gas-liquid separation. The separated gas is extracted by the negative pressure extraction device, and the separated liquid is retained in the water-gas separation device or discharged separately.

5. The controlled seepage drainage method for filling and dewatering underground mining areas as described in claim 1, characterized in that, The controlled seepage drainage type underground mining filling and dewatering method also includes a synergistic pressurization step: A reverse booster pipe, independent of the dewatering pipeline, is pre-installed inside the goaf; the reverse booster pipe is located inside or in the lower middle part of the goaf filling body. During the operation of the negative pressure extraction device, compressed gas or pressurizing medium is injected into the reverse pressurization pipe; By utilizing the negative pressure suction at the dewatering pipeline and the positive pressure at the reverse pressurization pipe, a directional pressure gradient is formed inside the filling slurry; Preferably, the selection of the reverse booster tube follows these rules: A permeable pipe with a microporous layer in its wall and overall deformable characteristics is selected as the reverse booster pipe; The microporous layer is used to prevent solid particles from entering the tube, and the deformable property is used to make the reverse pressure tube shrink or recover under external pressure changes to adapt to the deformation of the filling material.

6. An underground mining area filling and dewatering system, characterized in that, Used to implement the controlled seepage drainage underground mining filling and dewatering method as described in any one of claims 1-5; The underground mining area filling and dewatering system includes: A dewatering pipeline assembly is configured to be arranged inside the goaf to be filled for collecting moisture from the filling slurry in the goaf. The negative pressure extraction device is configured to be arranged outside the goaf area and has a power mechanism to generate negative pressure suction. Pipeline connectors are used to connect the water outlet of the dehydration pipeline assembly to the air inlet of the negative pressure extraction device. When the negative pressure extraction device is started, a negative pressure environment is formed inside the dewatering pipeline assembly to drive the water in the filling slurry into the dewatering pipeline assembly.

7. The underground mining area filling and dewatering system as described in claim 6, characterized in that, The dehydration pipeline assembly includes: The main dewatering pipe is used to extend along the direction of the goaf. Several auxiliary dewatering pipes are connected to the main dewatering pipe through joints and are distributed in a three-dimensional divergent manner relative to the main dewatering pipe to construct a seepage network covering different areas of the goaf.

8. The underground mining area filling and dewatering system as described in claim 6, characterized in that, The pipe body in the dehydration pipeline assembly adopts a composite structure; the composite structure includes: The inner core plate, a skeleton structure made of pressure-resistant material, is used to keep the internal flow channels of the tube unobstructed; An external filter membrane is a filter medium that covers the outside of the inner core plate. The pore size of the external filter membrane is adapted to the particle size distribution of the filling slurry.

9. The underground mining area filling and dewatering system as described in claim 6, characterized in that, The underground mining area filling and dewatering system also includes: A water-gas separation device is installed on the pipeline between the dehydration pipeline assembly and the negative pressure extraction device, and is used to separate the extracted fluid into gas and liquid.

10. The underground mining area filling and dewatering system as described in claim 6, characterized in that, The system also includes a co-boosting assembly; the co-boosting assembly includes: The reverse booster pipe is arranged independently of the dewatering pipeline assembly within the goaf area, and the pipe wall is provided with a microporous layer. A pressurization device is arranged outside the goaf and connected to the reverse pressurization pipe, and is used to inject pressurization medium into the reverse pressurization pipe.

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