A design method for water hazard prevention in sintered rock aquifers

Abstract

This invention provides a design method for water hazard prevention and control in sintered rock aquifers, comprising: investigating the geological and hydrogeological conditions of the mine to determine the distribution characteristics of sintered rock, the range of the aquifer, and the water-rich anomaly zone; constructing an evaluation system for the water-conductivity characteristics of the sintered rock aquifer; modifying the calculation formula for the development height of the water-conducting fracture zone in the sintered rock layer based on the residual fragmentation coefficient of the sintered rock, thereby achieving accurate determination of the development height of the water-conducting fracture zone in the overlying rock of the working face; constructing a hazard assessment system for the sintered rock aquifer based on the relationship between the sintered rock aquifer stratum and the development height of the water-conducting fracture zone; and proposing a "cut-drainage-construction" layered treatment method for the sintered rock aquifer based on the hazard assessment system. Compared with traditional aquifer water hazard treatment, this invention can not only more accurately determine the damage to the sintered rock aquifer, but also achieve more economical and efficient layered treatment, which is of great significance for preventing underground water inrush accidents and groundwater loss, and realizing safe, efficient, and green coal mining.

Description

Technical Field

[0001] This invention belongs to the field of mine water hazard prevention and control, and specifically relates to a design method for water hazard prevention and control in pyromorphic rock aquifers. Background Technology

[0002] Burnt rock is a special type of rock stratum formed under the high-temperature baking conditions of spontaneous combustion of coal seams, and is mainly distributed in Northwest my country. Burnt rock has well-developed pores and fissures, and has good water storage capacity and runoff channels. After receiving water from surrounding sources, it can easily become a strong aquifer.

[0003] Many mines face the challenge of mining coal resources beneath pyrophyllite aquifers. Coal seam mining leads to the development of overlying strata collapse and fissures, potentially turning pyrophyllite aquifers into water sources, causing mine water inrush accidents and groundwater loss. This not only severely restricts normal mine construction and production but also deteriorates the ecological environment of the mining area. Therefore, research on water hazard prevention for pyrophyllite aquifers in rocky desert areas is of great significance for preventing underground water inrush accidents, protecting water resources, and achieving safe, efficient, and green coal mining. Summary of the Invention

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to address the shortcomings of the existing technology by providing a design method for water hazard prevention in pyrometallurgical aquifers, comprising the following steps:

[0005] Step 1: Investigate the geological and hydrogeological conditions of the mine, determine the distribution characteristics of the igneous rock, the range of the aquifer, and the water-rich anomaly zone, and construct an evaluation system for the water conductivity characteristics of the igneous rock aquifer.

[0006] Step 2: Based on the residual breccia coefficient of the sintered rock, modify the formula for calculating the development height of the water-conducting fracture zone in the sintered rock layer;

[0007] Step 3: Construct a risk assessment system for the aquifer of the sintered rock based on the relationship between the aquifer position and the development height of the water-conducting fracture zone.

[0008] Step 4: Establish a layered treatment method for the aquifer of the ignition metamorphic rock based on the hazard assessment system, which involves interception, drainage, and construction.

[0009] Step 5: Conduct a secondary exploration of the sintered rock aquifer in the water-conducting fracture zone to verify the effectiveness of the prevention and control measures.

[0010] In step 1, the "three-exploration technology" and the physicochemical properties of coal and rock samples are used to obtain the spatial characteristics and water-bearing characteristics of the stratigraphy in the burned area. Based on the diagenetic morphology and mineral composition characteristics, the diagenetic temperature of the burnt rocks is inferred, the burnt rock types are classified, a geological model containing burnt rock aquifers is established, and a water conductivity evaluation system for burnt rock aquifers is proposed to achieve a safety assessment of mining risks.

[0011] By drilling to obtain rock samples from underground strata, the thickness, distribution, grade, mineral composition, color, and structure of the pyrophoric rocks and other bedding coal bodies are analyzed to determine the distribution range of the pyrophoric rocks and to delineate the thickness and distribution of aquifers.

[0012] Ground-penetrating radar (GPR) is used to detect underground structures and anomalies through feedback information, improving the resolution of underground imaging and acquiring geological data. This geological data includes topography, geological structures, ore body distribution, mineral types, and the average thickness h of altered rock strata. r The burial depths of the baked rock (h1), sintered rock (h2), and molten rock (h3) are as follows:

[0013] Hydrological observation wells were installed to monitor groundwater levels, flow rates, and water quality.

[0014] By combining geological and hydrological data, a hydrogeological model is established to simulate the flow and distribution of groundwater and analyze the flow direction and velocity of groundwater; pumping and recharge tests are conducted to determine the hydraulic conductivity and storage capacity of the aquifer; water level changes at different depths are monitored to analyze the impact of hydrogeological conditions on the hydraulic conductivity of the aquifer.

[0015] Using the above methods, the geological and hydrogeological conditions of the mine were investigated, the sintered rock area, the aquifer range, and the water-rich anomaly zone were determined, and the average aquifer thickness h was obtained. w .

[0016] In step 1, water pressure tests and pumping tests were conducted on borehole samples from different strata within the sintered rock layer. The results showed that the sintered rock layer samples exhibited the highest permeability, with a permeability coefficient greater than [value missing].

[0017] At 11.5 Lu, the borehole unit water inflow is between 0.2 and 0.6 L / s·m, and under confining pressure, the porosity exceeds 20%, indicating strong water conductivity in sintered rock layers. The permeability and water conductivity of sintered rock samples depend on the degree of sintering, falling between sintered and baked rock. Baked rock samples exhibit the weakest permeability; when the permeability coefficient is less than 1 Lu, the borehole unit water inflow is below 0.1 L / s·m, and under confining pressure, the porosity is less than 10%, indicating poor water conductivity in baked rock layers. The permeability coefficient of sintered rock layers is above 10... -7 ~10 2 Between cm / s;

[0018] Considering the aquifer position and the relationship between different types of igneous rock strata, the permeability coefficient K and hydraulic conductivity T are used as comprehensive evaluation criteria, where T = 864 × K × h w Based on the experimental results, the stratigraphic characteristics of the sintered rock, and the aquifer location of the sintered rock, a system for evaluating the water conductivity of the sintered rock aquifer is constructed:

[0019] The permeability coefficient K satisfies K≥(10) -3 ~102 The hydraulic conductivity T satisfies T≥10 -3 The aquifer's hydraulic conductivity index is strong.

[0020] The permeability coefficient K satisfies 10 -4 <K<10 -3 The hydraulic conductivity T satisfies 10 -3 <T<10 -5 The aquifer's hydraulic conductivity is moderate.

[0021] The permeability coefficient K satisfies K≤(10) -4 ~10 -7 The hydraulic conductivity T satisfies T≤10 -5 The aquifer's hydraulic conductivity index is weak.

[0022] In step 2, the development height of the water-conducting fracture zone in the overlying sintered rock strata is predicted. This prediction is made using a combination of empirical formulas summarized from mining areas, computer numerical simulations, physical similarity simulation experiments, integrated geophysical exploration techniques, ground nuclear magnetic resonance, and field observation methods. This invention references the calculation formula for the development height of the water-conducting fracture zone in all caving mining methods derived from measured data by Soviet scholar B.Y. Gveltsmann (Geveltzmann, Safe Mining Under Water [M]. Beijing: Coal Industry Press, 1980: 62-68). Combined with the classification characteristics of sintered rock, a formula for predicting the development height of the water-conducting fracture zone in the overlying sintered rock strata is proposed. The specific calculation formula is as follows:

[0023]

[0024] Where h s η is the height of the water-conducting fracture zone, m; η is the subsidence coefficient of the ignited rock strata, m; m is the coal seam thickness, m; K t denoted as the limiting curvature of the overlying sintered rock layer above the water-conducting fracture zone, and β as the movement angle of the overlying sintered rock layer (°). The mining angle of the overlying igneous rock strata is (°).

[0025] Step 2 also includes: After coal seam mining, the upper burnt rock strata subside. Due to the brecciation of the rock, η considers the height of the brecciation and fall of the upper rock strata above the water-conducting fracture zone, which is related to the residual brecciation coefficient of the rock.

[0026] Δ=m-(Hh o (k-1)cosα

[0027]

[0028] Among the three types of sintered rock, baked rock is numbered 1, sintered rock is numbered 2, and sintered lava rock is numbered 3; Δ is the height of the sintered rock layer's fragmentation and fall, in meters; k is the residual fragmentation coefficient of the rock, k1 is the residual fragmentation coefficient of baked rock, k2 is the residual fragmentation coefficient of sintered rock, and k3 is the residual fragmentation coefficient of sintered lava rock; H is the burial depth of the coal seam being mined, in meters; h o h1 is the burial depth of the sintered rock strata above the water-conducting fracture zone, in m; h2 is the burial depth of the baked rock, in m; h3 is the burial depth of the sintered rock, in m; l is the exposed length of the sintered rock strata, in m; r is the radius of influence of the sintered rock strata above the water-conducting fracture zone, in m; α is the dip angle of the coal seam, in °.

[0029] When h1≥h0>(h3-h r When the water-conducting fracture zone develops into the heated rock layer and bakes the rock layer, the formula for calculating the height Δ of the heated rock layer's fragmentation and fall is:

[0030] Δ=m-(Hh o (k1-1)cosα

[0031] When h2≥h0>h1, the water-conducting fracture zone develops into the sintered rock layer within the sintered rock layer. The formula for calculating the height Δ of the sintered rock layer's fragmentation and fall is:

[0032] Δ=m-(Hh o (k2-1)cosα

[0033] When h3≥h0>h2, the water-conducting fracture zone develops to the sintered rock layer and the sintered lava layer. The formula for calculating the height Δ of the sintered rock layer's fragmentation and fall is:

[0034] Δ=m-(Hh o (k3-1)cosα

[0035] The formula for calculating the height of the water-conducting fracture zone in the overlying sintered rock of the working face is as follows:

[0036]

[0037] Where i = 1, 2, 3;

[0038] Combining computer numerical simulation, physical similarity simulation test, and field observation methods, the development height of water-conducting fracture zones in coal mining overburden is comprehensively predicted. Separation phenomena generated during the uneven subsidence of the overlying burnt rock strata during mining are common in caving zones and fracture zones. Based on the duration and water conductivity, they can be divided into two types: fracture type and cavity type. The cavity type delamination is the main hazard to mines.

[0039] Step 3 includes: constructing a risk assessment system for the igneous rock aquifer based on the distribution of igneous rocks, aquifers, and water-rich anomalies, the development height of fracture zones in the overlying igneous rocks at the working face, and the water conductivity characteristics of the igneous rock aquifer.

[0040] If the height of the water-conducting fracture zone is less than the height of the aquifer in the sintered rock, h s ≤(h r +mh w No prevention or treatment is needed;

[0041] If the height of the water-conducting fracture zone is greater than the height of the aquifer in the sintered rock, h s ≥(h r +mh w The affected area is weakly hydroconductive, and there are no water-rich abnormal areas in or near the area. Drilling drainage grouting is performed.

[0042] If the height of the water-conducting fracture zone is greater than the height of the aquifer in the sintered rock, h s ≥(h r +mh w The affected area is of medium or strong water conductivity, or there is an abnormal water-rich area in or near the area, and the curtain grouting is used for drainage.

[0043] Step 4 includes: The specific methods for the layered treatment of the aquifer by interception, drainage, and construction of the metamorphic rock include:

[0044] The igneous rock aquifer within the water-conducting fracture zone is weakly water-conducting: Drill holes (also serving as observation holes) obliquely from both roadways towards the overlying igneous rock layer in the goaf along the working face advance direction for drainage and grouting sealing; During grouting, observe the changes in grouting pressure and grouting flow rate, adjust grouting parameters, and stop grouting when the grouting pressure reaches the design requirements or the grouting flow rate decreases by 55-65% compared to the initial flow rate;

[0045] The sintered rock aquifer within the water-conducting fracture zone has medium or strong water conductivity: a water-stopping curtain is set ahead of the coal mining face, and the two roadways of the working face are advanced. The drilling layout parameters are determined according to the high-pressure grouting equipment model, grout diffusion range and mining face layout. Drilling holes are made into the sintered rock layer with more pores and fractures in the lower part of the aquifer (the curtain line is set at the bedrock bottom plate 5m below the sintered rock aquifer); the high-pressure jet grouting method is used to make the grouting of each hole interconnected to cut off the water source and form a water-stopping curtain.

[0046] Step 4 includes using geophysical exploration methods, water exploration and release tests, water pressure tests and core observations to further explore the aquifer and water-rich anomaly zone of the sintered rock, determine the permeability and infiltration of the grouting curtain rock layer, and judge the water conductivity characteristics of the sintered rock aquifer.

[0047] To pass the hydrophobicity test, the following conditions must be met:

[0048] The first condition is that the hydraulic conductivity of the pyromorphic rock aquifer in the area affected by mining is reduced to weak or below;

[0049] The second condition is that the water pressure in the test well is less than 0.1 MPa and the water inflow is less than 100 m³ / h. 3 / h and the hourly change is less than 3%;

[0050] The third condition is that the area of ​​nearby water-rich anomalies has shrunk by more than 70%.

[0051] The third condition must be met, and either the first or second condition must be met.

[0052] Grouting effect test qualification requirements: A grouting curtain rock layer is formed in the lower part of the aquifer of the burnt metamorphic rock in the core, and the physical and mechanical properties meet the requirements of the water blocking and isolation layer.

[0053] The present invention also provides an electronic device, including a processor and a memory, the memory storing program code that, when executed by the processor, causes the processor to perform the steps of the method.

[0054] The present invention also provides a storage medium storing a computer program or instructions that, when the computer program or instructions are run on a computer, execute the steps of the method described.

[0055] Beneficial effects: Compared with traditional aquifer water hazard control, this invention can not only more accurately determine the damage of calcined rock aquifers, but also make layered treatment more economical and efficient. It is of great significance for preventing underground water inrush accidents and groundwater loss, and realizing safe, efficient and green coal mining. Attached Figure Description

[0056] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0057] Figure 1 This is a flowchart of the design method for preventing water hazards in aquifers of pyromorphic rocks according to the present invention.

[0058] Figure 2 This is a schematic diagram of the design method for preventing water hazards in a pyromorphic rock aquifer according to the present invention.

[0059] In the figure: 1-burnt rock aquifer; 2-water-rich anomaly zone; 3-water-conducting fracture zone; 4-affected area of ​​burnt rock aquifer; 5-working face roadway; 6-drainage borehole; 7-top interface of burnt rock aquifer; 8-surface; 9-grouting borehole; 10-water-stop curtain; 11-coal seam working face. Detailed Implementation

[0060] This invention provides a design method for water hazard prevention in calcined rock aquifers, comprising:

[0061] The geological and hydrogeological conditions of the mine were investigated to determine the extent of the igneous rock aquifer 1 and the water-rich anomaly zone 2. The development height of the water-conducting fracture zone 3 in the overlying igneous rock was estimated, and a water-conducting characteristic evaluation system for the igneous rock aquifer was constructed to assess the hazard level of igneous rock aquifer 1. If the aquifer is weakly conductive, directional borehole 6 was drilled to drain water and grout the igneous rock aquifer 4 that affects mining. If the aquifer is moderately or strongly conductive, grouting was used in borehole 9 to seal the fractures in the bottom plate of igneous rock aquifer 1, reducing the permeability of the affected area 4 of the igneous rock aquifer 1 and forming a water-stopping curtain 10. The igneous rock aquifer 1 was explored again to verify the prevention and control effect.

[0062] The design method and steps for water hazard prevention of sintered rock aquifers are as follows: Figure 1 As shown.

[0063] Existing geological and hydrogeological data from the mine were collected. Geophysical exploration methods, water exploration and release tests, laboratory determination of the physical and mechanical properties of coal and rock samples, measurement of geothermal gradient, and analysis of underground rock samples were employed to determine the distribution range of the igneous rocks and to delineate the thickness and distribution of aquifer 1. r The average thickness of the igneous rock strata is given in meters (m). Due to varying degrees of baking, the igneous rock strata are categorized from top to bottom as follows: a hard, rough, and porous igneous rock layer; a sintered rock layer with well-developed fissures and relatively high hardness; and a baked rock layer whose hardness has slightly increased compared to before baking, with predominantly closed fissures. h1 represents the burial depth of the baked rock layer (m); h2 represents the burial depth of the sintered rock layer (m); and h3 represents the burial depth of the igneous rock layer (m). Hydrological observation wells were installed to monitor groundwater level, flow rate, and water quality. A hydrogeological model was established using geological and hydrological data to simulate groundwater flow and distribution, analyze the flow direction and velocity of groundwater to understand the characteristics of the aquifer. Pumping and recharge tests were conducted to determine the hydraulic conductivity and storage capacity of the aquifer. Water level changes at different depths were monitored to analyze the influence of hydrogeological conditions on the hydraulic conductivity of the igneous rock aquifer. Using the above methods, the geological and hydrogeological conditions of the mine were comprehensively investigated, and the areas of sintered rock, aquifer range, and water-rich anomalies were identified. w The average thickness of the aquifer is in meters (m).

[0064] Pressure water tests and pumping tests were conducted on borehole samples from different strata within the igneous rock formations. The aquifer location and the stratigraphic relationships between different types of igneous rock were considered, using the permeability coefficient K (cm / s) and hydraulic conductivity T (m³) as the parameters. 2 / d) serves as the comprehensive evaluation criterion. Based on the experimental results, the stratigraphic characteristics of the igneous rock, and the igneous rock aquifer 1, an evaluation system for the water conductivity of the igneous rock aquifer is constructed, as shown in Table 1:

[0065] Table 1

[0066]

[0067] After coal seam mining, the overlying burnt rock strata subside. Due to the brecciation of the rock, η, considering the height of the brecciation and fall of the rock strata above the water-conducting fracture zone, is related to the residual brecciation coefficient of the rock.

[0068] Δ=m-(Hh o (k-1)cosα

[0069]

[0070] Among the three types of sintered rock, baked rock is numbered 1, sintered rock is numbered 2, and sintered lava rock is numbered 3. Δ represents the height of the sintered rock layer's fragmentation and fall, in meters; k is the residual fragmentation coefficient of the rock, k1 is the residual fragmentation coefficient of baked rock, k2 is the residual fragmentation coefficient of sintered rock, and k3 is the residual fragmentation coefficient of sintered lava rock; H is the burial depth of the coal seam being mined, in meters; h o denoted as ρ, the burial depth of the igneous rock strata above the water-conducting fracture zone (m); l is the exposed length of the igneous rock strata (m); r is the radius of influence of the igneous rock strata above the water-conducting fracture zone (m); α is the dip angle of the coal seam (°).

[0071] (1) When h1≥h0>(h3-h r At that time, the water-conducting fracture zone developed into the baked rock layer within the sintered rock layer;

[0072] Δ=m-(Hh o (k1-1)cosα

[0073] (2) When h2≥h0>h1, the water-conducting fracture zone develops into the sintered rock layer in the sintered rock layer;

[0074] Δ=m-(Hh o (k2-1)cosα

[0075] (3) When h3≥h0>h2, the water-conducting fracture zone develops into the sintered rock layer and the sintered lava layer.

[0076] Δ=m-(Hh o (k3-1)cosα

[0077] Based on the above formula, the formula for the development height of the water-conducting fracture zone in the overlying sintered rock of the working face is proposed as follows:

[0078]

[0079] By combining computer numerical simulation, physical similarity simulation experiments, and field observation methods, the development height of the water-conducting fracture zone 3 in the overlying strata of coal mining is comprehensively predicted, and the affected area 4 of the sintered rock aquifer 1 is determined.

[0080] Based on the distribution characteristics of igneous rocks, the distribution of igneous rock aquifer 1 and water-rich anomaly zone 2, the development height of the fracture zone in the overlying igneous rock at the working face, and the water conductivity assessment system of the igneous rock aquifer, a risk assessment system for igneous rock aquifers is constructed, as shown in Table 2:

[0081] Table 2

[0082]

[0083] Based on the hazard assessment system, a layered treatment method for igneous rock aquifers is proposed: "interception-dredging-construction".

[0084] (1) When the igneous rock aquifer 1 is unaffected, i.e., the water-conducting fracture zone 3 does not touch the igneous rock aquifer 1, no water hazard prevention measures are required. When the water-conducting fracture zone 3 touches the igneous rock aquifer 1, but the affected area 4 is weakly water-conducting, and there is no water-rich anomaly zone 2 in this area and its adjacent areas, the method of borehole drainage grouting is adopted:

[0085] Based on the predicted development height of the water-conducting fracture zone in the sintered rock and the aquifer occurrence, boreholes (also serving as observation holes) are drilled obliquely from both roadways towards the overlying sintered rock strata in the goaf along the working face advance direction to drain water from the fractured layers of the sintered rock. The boreholes are spaced approximately 6-10 meters apart on one side, with a diameter generally of 100-160 mm, and the drilling depth penetrates the sintered rock aquifer. The drainage flow rate and timing are determined based on the permeability of the sintered rock aquifer, drainage requirements, and water volume. Drainage is carried out when the borehole water pressure is less than 0.1 MPa and the borehole inflow is less than 100 m³ / h. 3 When the water level changes by less than 3% per hour, the drainage is considered complete. During the drainage process, closely monitor the drainage volume and water level changes, and adjust the drainage parameters promptly. Based on the characteristics of the calcined rock aquifer, cement grout, gangue grout, etc., can be selected as the grouting material. (The water-cement ratio of cement grout is generally 0.5:1-1:1. Appropriate amounts of water-reducing agents and early-strength agents can be added to improve the grout's performance. Gangue grout is made by mixing gangue, expanding filler, and cement grout; the grout sets quickly and has a certain degree of toughness.) After drainage, first inject expanding filler material into the upper part of the fissure (approximately 1 / 3 to 2 / 3 of the total fissure height) for initial sealing. Then, insert the grouting pipe into the borehole. The diameter and length of the grouting pipe are determined according to the grouting pressure and grouting volume (the grouting pressure is adjusted according to the permeability of the aquifer and the degree of fissure development, generally 2-4 MPa; the grouting flow rate is adjusted according to the grouting pressure and borehole diameter, generally 40-80 L / min). Grouting and sealing are then performed. During grouting, observe the changes in grouting pressure and flow rate, and adjust the grouting parameters. Grouting is stopped when the grouting pressure reaches the design requirements or the grouting flow rate significantly decreases.

[0086] (2) When the water-conducting fracture zone 3 touches the sintered rock aquifer 1, the affected area 4 is of medium to strong water conductivity, or there is a water-rich abnormal zone 2 in this area and the adjacent area, water hazard prevention is carried out by drilling curtain grouting to block the water source: a water-stopping curtain is set in advance of the coal mining face, and the two roadways of the working face are advanced. The drilling layout parameters are determined according to the high-pressure grouting equipment model, slurry diffusion range and mining face layout. The boreholes are arranged in a close circle with a radius of about 10-14m. The borehole diameter is 0.8-1.2m and perpendicular to the rock strata to ensure the grouting effect. The boreholes are drilled to the sintered rock layer with more pores and fractures in the lower part of the aquifer (the curtain line is set at the bedrock bottom plate 5m below the sintered rock aquifer). According to the characteristics of the sintered rock bottom layer, the grouting material can be selected as ultra-fine cement slurry, water glass-slag powder-cement grouting material, etc. High-pressure jet grouting is used to insert grouting pipes into boreholes. The diameter and length of the grouting pipes are determined by the grouting pressure and grouting volume. High-pressure jet grout quickly fills the pores, and the grouting in each borehole is interconnected to isolate the water source, forming a water-stopping curtain. During the grouting process, the changes in grouting pressure and grouting flow rate are observed, and the grouting parameters are adjusted. Grouting is stopped when the grouting pressure reaches the design requirements or when the rate of increase of the pressure at the top of the curtain is relatively small compared to the pressure at the bottom.

[0087] In this case, the water-conducting fracture zone penetrates the aquifer 1 of the sintered rock, the affected area 4 has strong water conductivity, and there is an anomalous water-rich area 2. Water hazard prevention and control are carried out by drilling to drain water and curtain grouting.

[0088] A secondary exploration was conducted on the sintered rock aquifer in the water-conducting fracture zone: using geophysical exploration methods, water exploration and release tests, water pressure tests, and core observations, the sintered rock aquifer 1 and the water-rich anomaly zone 2 were explored again. The permeability, infiltration, and other physical and mechanical parameters of the grouting curtain rock layer were measured to evaluate the water-conducting characteristics of the sintered rock aquifer. The drainage effect test requirements were: the water conductivity of the sintered rock aquifer affected by mining in area 4 was reduced to weak or below, and the area of ​​the water-rich anomaly zone 2 within and near it was reduced by more than 70%; the water pressure in the water exploration and release test borehole was less than 0.1 MPa, the borehole inflow was less than 100 m³ / h, and the hourly variation was less than 3%. The grouting effect test requirements were: a grouting curtain rock layer was formed in the lower part of the sintered rock aquifer in the core, and its physical and mechanical properties met the requirements for a water-blocking isolation layer. This indicates that the water-stopping measures in the project met the design requirements, the permeability of the overlying sintered rock was significantly reduced, and the water hazard prevention of the sintered rock aquifer was effective.

[0089] This invention provides a design method for preventing water hazards in calcined rock aquifers. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A design method for preventing water hazards in a pyrometallurgical aquifer, characterized in that, Includes the following steps: Step 1: Investigate the geological and hydrogeological conditions of the mine, determine the distribution characteristics of the igneous rock, the range of the aquifer, and the water-rich anomaly zone, and construct an evaluation system for the water conductivity characteristics of the igneous rock aquifer. Step 2: Based on the residual breccia coefficient of the sintered rock, modify the formula for calculating the development height of the water-conducting fracture zone in the sintered rock layer; Step 3: Construct a risk assessment system for the aquifer of the sintered rock based on the relationship between the aquifer position and the development height of the water-conducting fracture zone. Step 4: Establish a layered treatment method for the aquifer of the ignition metamorphic rock based on the hazard assessment system, which involves interception, drainage, and construction. Step 5: Conduct a secondary exploration of the sintered rock aquifer in the water-conducting fracture zone to verify the effectiveness of the prevention and control measures; Step 3 includes: constructing a risk assessment system for the sintered rock aquifer based on the distribution of aquifers and water-rich anomalies, the development height of fracture zones in the overlying sintered rock at the working face, and the water conductivity characteristics of the sintered rock aquifer. If the height of the water-conducting fracture zone is less than the height of the aquifer in the sintered rock, h s ≤(h r +mh w ), no prevention or treatment is needed; among them h s m is the height of the water-conducting fracture zone; h is the thickness of the coal seam. r h represents the average thickness of the igneous rock strata. w The average thickness of the aquifer; If the height of the water-conducting fracture zone is greater than the height of the aquifer in the sintered rock, h s ≥(h r +mh w The affected area is weakly hydroconductive, and there are no water-rich abnormal areas in or near the area. Drilling drainage grouting is performed. If the height of the water-conducting fracture zone is greater than the height of the aquifer in the sintered rock, h s ≥(h r +mh w ), where the affected area is of medium or strong water conductivity, or where there is an abnormally rich water area in or near the area, curtain grouting is used for drainage; Step 4 includes: The specific methods for the layered treatment of the aquifer by interception, drainage, and construction of the metamorphic rock include: The igneous rock aquifer within the water-conducting fracture zone is weakly water-conducting: Drill holes obliquely from both roadways toward the overlying igneous rock layer in the goaf along the working face advance direction for drainage and grouting sealing; During grouting, observe the changes in grouting pressure and grouting flow rate, adjust grouting parameters, and stop grouting when the grouting pressure reaches the design requirements or the grouting flow rate decreases by 55-65% compared to the initial flow rate; The sintered rock aquifer within the water-conducting fracture zone has medium or strong water conductivity: a water-stopping curtain is set up ahead of the coal mining face, and the two roadways of the working face are excavated ahead of the face. The drilling layout parameters are determined according to the high-pressure grouting equipment model, grout diffusion range and mining face layout. Drill holes to the sintered rock layer with more pores and fractures in the lower part of the aquifer. High-pressure jet grouting is used to make the grouting of each hole interconnected to cut off the water source and form a water-stopping curtain.

2. The method according to claim 1, characterized in that, In step 1, the three exploration techniques and the physicochemical properties of coal and rock samples are used to obtain the spatial characteristics and water-bearing characteristics of the stratigraphy in the burned area. Based on the diagenetic morphology and mineral composition characteristics, the diagenetic temperature of the burnt rocks is inferred, the burnt rock types are classified, a geological model containing burnt rock aquifers is established, and a water conductivity evaluation system for burnt rock aquifers is proposed to achieve a safety assessment of mining risks. By drilling to obtain rock samples from underground strata, the thickness, distribution, grade, mineral composition, color, and structure of the pyrophoric rocks and other bedding coal bodies are analyzed to determine the distribution range of the pyrophoric rocks and to delineate the thickness and distribution of aquifers. Ground-penetrating radar (GPR) is used to detect underground structures and anomalies through feedback information, improving the resolution of underground imaging and acquiring geological data. This geological data includes topography, geological structures, ore body distribution, mineral types, and the average thickness h of altered rock strata. r The burial depths of the baked rock (h1), sintered rock (h2), and molten rock (h3) are as follows: Hydrological observation wells were installed to monitor groundwater levels, flow rates, and water quality. By combining geological and hydrological data, a hydrogeological model is established to simulate the flow and distribution of groundwater and analyze the flow direction and velocity of groundwater; pumping and recharge tests are conducted to determine the hydraulic conductivity and storage capacity of the aquifer; water level changes at different depths are monitored to analyze the impact of hydrogeological conditions on the hydraulic conductivity of the aquifer. Using the above methods, the geological and hydrogeological conditions of the mine were investigated, the sintered rock area, the aquifer range, and the water-rich anomaly zone were determined, and the average aquifer thickness h was obtained. w .

3. The method according to claim 2, characterized in that, In step 1, water pressure tests and pumping tests were conducted on borehole samples from different strata in the sintered rock layer. The results showed that the sintered rock layer had the strongest permeability. When the permeability coefficient was greater than 11.5 Lu, the unit water inflow of the borehole was between 0.2 and 0.6 L / s·m. Furthermore, the porosity exceeded 20% under the confining pressure, indicating that the sintered rock layer had strong water conductivity. The permeability and water conductivity of sintered rock samples depend on the degree of sintering, falling between sintered and baked rock. Baked rock samples exhibit the weakest permeability; when the permeability coefficient is less than 1 Lu, the borehole yield is below 0.1 L / s·m, and under confining pressure, the porosity is less than 10%. Baked rock samples also have poor water conductivity. Sintered rock samples have a permeability coefficient exceeding 10... -7 ~10 2 Between cm / s; Considering the aquifer position and the relationship between different types of igneous rock strata, the permeability coefficient K and hydraulic conductivity T are used as comprehensive evaluation criteria, where T = 864 × K × h w Based on the experimental results, the stratigraphic characteristics of the sintered rock, and the aquifer location of the sintered rock, a system for evaluating the water conductivity of the sintered rock aquifer is constructed: The permeability coefficient K satisfies K≥(10) -3 ~10 2 The hydraulic conductivity T satisfies T≥10 -3 The aquifer's hydraulic conductivity index is strong. The permeability coefficient K satisfies 10 -4 <K<10 -3 The hydraulic conductivity T satisfies 10 -3 <T<10 -5 The aquifer's hydraulic conductivity is moderate. The permeability coefficient K satisfies K≤(10) -4 ~10 -7 The hydraulic conductivity T satisfies T≤10 -5 The aquifer's hydraulic conductivity index is weak.

4. The method according to claim 3, characterized in that, In step 2, the development height of the water-conducting fracture zone in the overlying sintered rock strata is predicted. This prediction is based on a combination of empirical formulas from the mining area, computer numerical simulation, physical similarity simulation experiments, integrated geophysical exploration techniques, surface nuclear magnetic resonance, and field observation methods. Furthermore, considering the classification characteristics of sintered rock, a formula for predicting the development height of the water-conducting fracture zone in the overlying sintered rock strata is proposed, and the specific calculation formula is as follows: Where η is the subsidence coefficient of the ignition rock layer; K t β represents the limiting curvature of the overlying sintered rock layer above the water-conducting fracture zone, and β is the movement angle of the overlying sintered rock layer. The angle of mining is the overlying pyromorphic rock strata.

5. The method according to claim 4, characterized in that, Step 2 also includes: After coal seam mining, the upper burnt rock strata subside. Due to the brecciation of the rock, η considers the height of the brecciation and fall of the upper rock strata above the water-conducting fracture zone, which is related to the residual brecciation coefficient of the rock. Δ=m-(H-h o )(k-1)cosα Among the three types of sintered rock, baked rock is numbered 1, sintered rock is numbered 2, and sintered lava rock is numbered 3; Δ is the height of the sintered rock layer's fragmentation and fall; k is the residual fragmentation coefficient of the rock, k1 is the residual fragmentation coefficient of baked rock, k2 is the residual fragmentation coefficient of sintered rock, and k3 is the residual fragmentation coefficient of sintered lava rock; H is the burial depth of the coal seam being mined; h o h1 is the burial depth of the sintered rock strata above the water-conducting fracture zone; h2 is the burial depth of the baked rock; h3 is the burial depth of the sintered rock; l is the exposed length of the sintered rock strata; r is the radius of influence of the sintered rock strata above the water-conducting fracture zone; α is the dip angle of the coal seam. When h1≥h0>(h3-h r When the water-conducting fracture zone develops into the heated rock layer and bakes the rock layer, the formula for calculating the height Δ of the heated rock layer's fragmentation and fall is: Δ=m-(H-h o )(k1-1)cosα When h2≥h0>h1, the water-conducting fracture zone develops into the sintered rock layer within the sintered rock layer. The formula for calculating the height Δ of the sintered rock layer's fragmentation and fall is: Δ=m-(H-h o )(k2-1)cosα When h3≥h0>h2, the water-conducting fracture zone develops to the sintered rock layer and the sintered lava layer. The formula for calculating the height Δ of the sintered rock layer's fragmentation and fall is: Δ=m-(H-h o )(k3-1)cosα The formula for calculating the height of the water-conducting fracture zone in the overlying sintered rock of the working face is as follows: Where i = 1, 2, 3.

6. The method according to claim 5, characterized in that, Step 4 includes using geophysical exploration methods, water exploration and release tests, water pressure tests and core observations to further explore the aquifer and water-rich anomaly zone of the sintered rock, determine the permeability and infiltration of the grouting curtain rock layer, and judge the water conductivity characteristics of the sintered rock aquifer. To pass the hydrophobicity test, the following conditions must be met: The first condition is that the hydraulic conductivity of the pyromorphic rock aquifer in the area affected by mining is reduced to weak or below; The second condition is that the water pressure in the test well is less than 0.1 MPa and the water inflow is less than 100 m³ / h. 3 / h and the hourly change is less than 3%; The third condition is that the area of ​​nearby water-rich anomalies has shrunk by more than 70%. The third condition must be met, and either the first or second condition must be met. Grouting effect test qualification requirements: A grouting curtain rock layer is formed in the lower part of the aquifer of the burnt metamorphic rock in the core, and the physical and mechanical properties meet the requirements of the water blocking and isolation layer.

7. An electronic device, characterized in that, It includes a processor and a memory, the memory storing program code that, when executed by the processor, causes the processor to perform the steps of the method as described in any one of claims 1 to 6.

8. A storage medium, characterized in that, It stores a computer program or instructions that, when run on a computer, perform the steps of the method as described in any one of claims 1 to 6.

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