Design method for preventing and controlling water damage of burnt rock aquifer

Abstract

The invention provides a burnt rock aquifer water disaster prevention and control design method which comprises the following steps: exploring mine geological and hydrogeological conditions, determining burnt rock distribution characteristics, an aquifer range and a water-rich abnormal region, and constructing a burnt rock aquifer water diversion characteristic judgment system; on the basis of the residual bursting coefficient of the burnt rock, a calculation formula of the development height of the burnt rock stratum water-flowing fractured zone is corrected, and the development height of the working face mining overlying strata water-flowing fractured zone is accurately judged through the formula; constructing a burnt rock water-bearing layer risk evaluation system according to the relationship between the burnt rock water-bearing layer position and the development height of the water-flowing fractured zone; according to the danger evaluation system, the'intercepting-dredging-building 'burnt rock aquifer layering treatment method is provided. Compared with traditional aquifer water disaster treatment, the method has the advantages that the aquifer damage of the burnt rock can be judged more accurately, layered treatment is more economical and efficient, and the method is of great significance to prevention of underground water inrush accidents and underground water loss and realization of safe, efficient and green mining of coal.

Description

Technical Field

[0001] The 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 a burned rock aquifer. Background Art

[0002] Burnt rock is a special rock layer formed under the high temperature baking conditions of coal seam spontaneous combustion, mainly distributed in the northwest of my country. Burnt rock has well-developed holes and cracks, has good water storage performance and runoff channels, and is easy to become a strong aquifer after receiving water supply from the surrounding sources.

[0003] Many mines are facing the problem of mining coal resources under the burnt rock aquifer. Coal mining leads to the development of overburden collapse and fissures, and the burnt rock aquifer may become a water source, causing mine water inrush accidents and groundwater resource loss, which not only seriously restricts the normal construction and production of mines, but also deteriorates the ecological environment of mining areas. Therefore, research on water hazard prevention and control of burnt rock aquifers in rocky desert areas is of great significance for preventing underground water inrush accidents and protecting water resources, and realizing 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 provide a design method for water hazard prevention and control of a burned rock aquifer in view of the shortcomings of the prior art, including the following steps:

[0005] Step 1: Explore the geological and hydrogeological conditions of the mine, determine the distribution characteristics of the burned rock, the range of the aquifer and the abnormally rich water area, and build a system for evaluating the water conductivity characteristics of the burned rock aquifer;

[0006] Step 2, based on the residual expansion coefficient of the burned rock, correct the calculation formula for the height of the water-conducting fracture zone in the burned rock layer;

[0007] Step 3, constructing a burnt rock aquifer risk assessment system based on the relationship between the burnt rock aquifer layer and the height of the water-conducting fracture zone;

[0008] Step 4: Establish a stratified management method for the burned rock aquifer by interception, drainage and construction based on the risk assessment system;

[0009] Step 5: Conduct secondary exploration of the burned rock aquifer in the water-conducting fracture zone to test the prevention and control effect.

[0010] In step 1, the "three-exploration technology" and physical and chemical properties of coal and rock samples are used to obtain the spatial characteristics and water-rich characteristics of the strata in the burned area. According to the diagenetic morphology and mineral component characteristics, the diagenetic temperature of the burned rock is inferred, the burned rock types are classified, and a geological model of the burned rock aquifer is established. A system for evaluating the water conductivity characteristics of the burned rock aquifer is proposed to achieve a safe assessment of mining risks.

[0011] Obtain rock samples from underground rock formations through drilling, analyze the thickness, distribution and grade of the burned rock and other stratified coal rock bodies, as well as the mineral composition, color and structure, determine the distribution range of the burned rock, and divide the thickness and distribution of the aquifer;

[0012] Geological radar is used to detect underground structures and anomalies through feedback information, improve the resolution of underground imaging, and obtain geological data, including topography, geological structure, ore body distribution, mineral type, average thickness of burned rock layer, etc. r , the burial depth of baked rock is h1, the burial depth of sintered rock is h2 and the burial depth of burned lava rock is h3;

[0013] Set up hydrological observation wells to monitor groundwater level, flow and water quality;

[0014] Combine geological and hydrological data to establish a hydrogeological model, simulate the flow and distribution of groundwater, and analyze the flow direction and speed of groundwater; conduct pumping tests and recharge tests to determine the conductivity and water storage capacity of the aquifer; monitor water level changes at different depths and analyze the impact of hydrogeological conditions on the conductivity of the aquifer;

[0015] Through the above methods, the geological and hydrogeological conditions of the mine were explored, the burned rock area, the aquifer range and the water-rich abnormal area were determined, and the average thickness of the aquifer h was obtained. w .

[0016] In step 1, water pressure test and pumping test were carried out on the drilled rock samples at different layers in the burnt rock layer. It was found that the rock samples of the burnt rock layer had the strongest permeability.

[0017] When the permeability coefficient is less than 1Lu, the unit water inflow of the borehole is between 0.2 and 0.6L / s·m, and the porosity is more than 20% under the storage confining pressure, and the water conductivity of the calcined rock layer is strong; the permeability and water conductivity of the sintered rock layer samples depend on the sintering degree, which is between sintered rock and baked rock; the permeability of the baked rock layer samples is the weakest. When the permeability coefficient is less than 1Lu, the unit water inflow of the borehole is less than 0.1L / s·m, and the porosity is less than 10% under the storage confining pressure, the water conductivity of the baked rock layer is poor, and the permeability coefficient of the burned rock layer is 10 -7 ~10 2 Between cm / s;

[0018] Considering the relationship between the aquifer and different types of burned rock layers, the permeability coefficient K and hydraulic conductivity T are used as comprehensive evaluation criteria, where T = 864 × K × h w According to the test results, the characteristics of the burned rock layer and the burned rock aquifer layer, a system for judging the water conductivity characteristics of the burned rock aquifer is constructed:

[0019] The permeability coefficient K satisfies K≥(10 -3 ~102 ), hydraulic conductivity T satisfies T≥10 -3 , the water conductivity index of the aquifer is strong water conductivity;

[0020] The permeability coefficient K satisfies 10 -4 <K<10 -3 , hydraulic conductivity T satisfies 10 -3 <T<10 -5 , the water conductivity index of the aquifer is medium water conductivity;

[0021] The permeability coefficient K satisfies K≤(10 -4 ~10 -7 ), hydraulic conductivity T satisfies T≤10 -5 , the water conductivity index of the aquifer is weak water conductivity.

[0022] In step 2, the height of the water-conducting fracture zone in the overlying burned rock strata during mining of the working face is estimated. The height of the water-conducting fracture zone in the overlying burned rock strata during mining of the coal is estimated by using the empirical formula summarized in the mining area, computer numerical simulation, physical similarity simulation test, comprehensive geophysical prospecting technology, ground nuclear magnetic resonance and field observation method. The present invention refers to the calculation formula for the height of the water-conducting fracture zone in the overlying burned rock strata during mining of the coal face by using the measured data of the Soviet scholar Б·я·гвельцман (Gwiertzman. Safe Coal Mining Under Water [M]. Beijing: Coal Industry Press, 1980: 62-68), and combines the classification characteristics of burned rock to propose a prediction of the height of the water-conducting fracture zone in the overlying burned rock strata during mining of the working face. The specific calculation formula is as follows:

[0023]

[0024] where h s is the height of the water-conducting fracture zone, m; η is the sinking coefficient of the burned rock layer, m; m is the thickness of the coal seam, m; K t is the limiting curvature of the burned rock layer above the water-conducting fracture zone, β is the movement angle of the overlying burned rock layer, (°); is the mining angle of the overlying burned rock strata, (°).

[0025] Step 2 also includes: after the coal seam is mined, the upper burned rock layer sinks. Due to the crushing and swelling of the rock, η considers the height of the upper rock layer in the water-conducting fracture zone to crack and swell, which is related to the residual crushing and swelling coefficient of the rock:

[0026] Δ=m-(Hh o )(k-1)cosα

[0027]

[0028] Among them, the three types of burned rocks are baked rock numbered 1, sintered rock numbered 2, and burned lava rock numbered 3; Δ is the falling height of the burned rock layer, m; k is the residual expansion coefficient of the rock, k1 is the residual expansion coefficient of baked rock, k2 is the residual expansion coefficient of sintered rock, and k3 is the residual expansion coefficient of burned lava rock; H is the burial depth of the mined coal seam, m; h o is the burial depth of the burned rock layer above the water-conducting fracture zone, m; h1 is the burial depth of the baked rock, m; h2 is the burial depth of the sintered rock, m; h3 is the burial depth of the burned lava rock, m; l is the exposed length of the burned rock layer, m; r is the influence radius of the burned rock layer above the water-conducting fracture zone, m; α is the inclination angle of the coal seam, (°);

[0029] When h1≥h0>(h3-h r ), the water-conducting fracture zone develops to the baked rock layer in the burned rock layer, and the calculation formula for the falling height Δ of the burned rock layer is:

[0030] Δ=m-(Hh o )(k1-1)cosα

[0031] When h2≥h0>h1, the water-conducting fracture zone develops to the sintered rock layer in the burned rock layer, and the calculation formula for the falling height Δ of the burned rock layer is:

[0032] Δ=m-(Hh o )(k2-1)cosα

[0033] When h3≥h0>h2, the water-conducting fracture zone develops to the burned rock layer and the lava layer, and the calculation formula for the falling height Δ of the burned rock layer is:

[0034] Δ=m-(Hh o )(k3-1)cosα

[0035] The calculation formula for the height of the water-conducting fracture zone in the overlying burned rock during mining of the working face is:

[0036]

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

[0038] Combining computer numerical simulation, physical similarity simulation test and field observation method, the development height of overburden water-conducting fracture zone in coal mining is comprehensively predicted. The separation phenomenon caused by uneven subsidence of overlying burned rock strata during mining is common in collapse zones and fracture zones. According to the duration and water conductivity, it can be divided into two types: fracture type and cavity type. The cavity type separation is the main type that causes harm to mines.

[0039] Step 3 includes: constructing a burnt rock aquifer risk assessment system based on the distribution of burnt rocks, aquifers and water-rich anomalies, the height of the burnt rock fracture zone overlying the working face mining, and the assessment system of the water conductivity characteristics of the burnt rock aquifer:

[0040] If the height of the water-conducting fracture zone is less than the height of the burned rock aquifer, h s ≤(h r +mh w ), no prevention or treatment is required;

[0041] If the height of the water-conducting fracture zone is greater than the height of the burned rock aquifer, h s ≥(h r +mh w ), the affected area is weakly water-conductive, and there is no abnormally water-rich area in or near the area, and drilling and drainage grouting is performed;

[0042] If the height of the water-conducting fracture zone is greater than the height of the burned rock aquifer, h s ≥(h r +mh w ), the affected area is of medium or strong water conductivity, or there are abnormally water-rich areas in and near the area, and curtain grouting is used to drain water.

[0043] Step 4 includes: the method for layered management of the cut-off, dredging and building burnt rock aquifer specifically includes:

[0044] The burned rock aquifer in the water-conducting fracture zone has weak water conductivity: along the advancing direction of the working face, holes are drilled obliquely from two lanes toward the burned rock layer overlying the goaf (also used as observation holes) to drain water and grout to seal; during the grouting process, the changes in grouting pressure and grouting flow are observed, and the grouting parameters are adjusted. When the grouting pressure reaches the design requirements or the grouting flow is reduced by 55-65% compared with the initial flow, the grouting is terminated;

[0045] The burned rock aquifer in the water-conducting fracture zone has medium or strong water conductivity: a water-stop curtain is set in advance at the coal mining face, and the two tunnels of the working face are excavated in advance. The drilling layout parameters are determined according to the model of high-pressure grouting equipment, the slurry diffusion range and the layout of the mining face. Drill holes into the burned lava layer with more pores and fractures in the lower part of the aquifer (the curtain line is set at the bedrock bottom 5m below the burned rock aquifer); use high-pressure rotary jet grouting method to make the grouting of each borehole conduct to each other to cut off the water source and form a water-stop curtain.

[0046] Step 4 includes using geophysical exploration methods, water exploration and release tests, water pressure tests and core observations to re-explore the burned rock aquifer and the abnormally rich water area, measure the water permeability and permeability of the grouting curtain rock layer, and determine the water conductivity characteristics of the burned rock aquifer;

[0047] The following conditions must be met to meet the hydrophobic effect test requirements:

[0048] The first condition is that the water conductivity of the burned rock aquifer in the mining-affected area is reduced to weak or below;

[0049] The second condition is that the water pressure in the water exploration and drainage test hole is less than 0.1MPa and the water inflow in the hole is less than 100m 3 / h and the hourly change is less than 3%;

[0050] The third condition is that the area of ​​the nearby water-rich anomaly area is reduced by more than 70%;

[0051] Among them, the third condition must be met, and either the first or the second condition must be met;

[0052] Qualified requirements for grouting effect detection: A grouting curtain rock layer is formed at the bottom of the burned rock aquifer in the core, and its physical and mechanical properties meet the requirements of the water blocking isolation layer.

[0053] The present invention also provides an electronic device, comprising a processor and a memory, wherein the memory stores program code, and when the program code is executed by the processor, the processor executes the steps of the described method.

[0054] The present invention also provides a storage medium storing a computer program or instruction. When the computer program or instruction is run on a computer, the steps of the method described are executed.

[0055] Beneficial effects: Compared with traditional aquifer water hazard management, the present invention can not only more accurately determine the damage of the burned rock aquifer, but also make the layered management more economical and efficient. It is of great significance to prevent underground water inrush accidents and groundwater loss, and to achieve safe, efficient and green coal mining. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0057] Figure 1 It is a flow chart of the design method for preventing and controlling water hazards in a burned rock aquifer of the present invention.

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

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

[0060] The embodiment of the present invention provides a design method for preventing and controlling water hazards in a burned rock aquifer, comprising:

[0061] Explore the geological and hydrogeological conditions of the mine, determine the scope of the burned rock aquifer 1 and the abnormally rich water-rich area 2; predict the height of the water-conducting fracture zone 3 of the overlying burned rock layer of mining, build a burnt rock aquifer water-conducting characteristic evaluation system, and evaluate the danger level of the burned rock aquifer 1; if the aquifer is weakly conductive, construct directional drilling 6, drain water and inject grout into the burned rock aquifer 4 that affects mining; if the aquifer is medium or strong in conductivity, use drilling 9 to inject grout to seal the cracks in the bottom plate of the burned rock aquifer 1, reduce the permeability of the affected area 4 of the burned rock aquifer, and form a water-stop curtain 10. Explore the burned rock aquifer 1 again to test the prevention and control effect.

[0062] The steps of design method for water hazard prevention and control of burned rock aquifer are as follows: Figure 1 shown.

[0063] Collect existing geological and hydrogeological data of the mine, use geophysical exploration methods, water exploration and drainage tests, laboratory determination methods of physical and mechanical properties of coal and rock samples, measurement of geothermal gradients, drilling and analysis of underground rock samples, etc., to determine the distribution range of burned rocks, divide the thickness and distribution of aquifers, h r is the average thickness of the burned rock layer, m; due to the different degrees of baking, the burned rock layers are divided from top to bottom into burnt lava layers with hard rock and rough surface and multiple pores, burnt rock layers with developed cracks and high hardness, and baked rock layers with slightly increased hardness and mainly closed cracks compared with before baking. h1 is the burial depth of baked rock, m; h2 is the burial depth of sintered rock, m; h3 is the burial depth of burned lava rock, m. Set up hydrological observation wells to monitor groundwater level, flow and water quality. Combine geological and hydrological data to establish a hydrogeological model, simulate the flow and distribution of groundwater, analyze the flow direction and speed of groundwater, and understand the characteristics of the aquifer; conduct pumping tests and recharge tests to determine the water conductivity and water storage capacity of the aquifer. Monitor water level changes at different depths and analyze the impact of hydrogeological conditions on the water conductivity of the burned rock aquifer. Through the above methods, the geological and hydrogeological conditions of the mine are comprehensively explored, and the burned rock area, aquifer range and water-rich abnormal area are determined. w is the average thickness of the aquifer, m.

[0064] Water pressure test and pumping test were carried out on the borehole samples in different layers of the burnt rock strata. The relationship between the aquifer layer and the layers of different types of burnt rock strata was considered. The permeability coefficient K (cm / s) and hydraulic conductivity T (m 2 / d) is a comprehensive evaluation standard. According to the test results, the characteristics of the burned rock layer and the burned rock aquifer 1, a burnt rock aquifer water conductivity evaluation system is constructed, as shown in Table 1:

[0065] Table 1

[0066]

[0067] After coal seam mining, the upper burned rock layer sinks. Due to the rock expansion, η considers the height of the upper rock layer in the water-conducting fracture zone due to cracking and expansion, which is related to the residual expansion coefficient of the rock:

[0068] Δ=m-(Hh o )(k-1)cosα

[0069]

[0070] Among the three types of burnt rock, baked rock is numbered 1, sintered rock is numbered 2, and burnt lava rock is numbered 3. Δ is the falling height of the burnt rock layer, m; k is the residual expansion coefficient of the rock, k1 is the residual expansion coefficient of the baked rock, k2 is the residual expansion coefficient of the sintered rock, and k3 is the residual expansion coefficient of the burnt lava rock; H is the burial depth of the mined coal seam, m; h o is the burial depth of the burnt rock stratum above the water-conducting fracture zone, m; l is the exposed length of the burnt rock stratum, m; r is the influence radius of the burnt rock stratum above the water-conducting fracture zone, m; α is the inclination angle of the coal seam, (°).

[0071] (1) When h1≥h0>(h3-h r ) when the water-conducting fracture zone develops into the baked rock layer in the burned 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 burned rock layer;

[0074] Δ=m-(Hh o )(k2-1)cosα

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

[0076] Δ=m-(Hh o )(k3-1)cosα

[0077] Combined with the above formula, the formula for the height of the water-conducting fracture zone in the overlying burned rock during mining of the working face is proposed as follows:

[0078]

[0079] Combining computer numerical simulation, physical similarity simulation test and field observation method, the development height of overburden water-conducting fracture zone 3 caused by coal mining is comprehensively predicted, and the affected area 4 of the burned rock aquifer 1 is determined.

[0080] According to the distribution characteristics of burned rocks, the distribution of burned rock aquifer 1 and water-rich abnormal area 2, the development height of the burned rock fracture zone overlying the working face mining and the evaluation system of the water conductivity characteristics of the burned rock aquifer, a burned rock aquifer hazard evaluation system is constructed, as shown in Table 2:

[0081] Table 2

[0082]

[0083] According to the risk assessment system, a stratified management method of "interception-drainage-construction" for burnt rock aquifers is proposed:

[0084] (1) When the burned rock aquifer 1 is not affected, that is, the water-conducting fracture zone 3 does not touch the burned rock aquifer 1, no water hazard prevention measures are required. When the water-conducting fracture zone 3 touches the burned rock aquifer 1, but the affected area 4 is weakly water-conductive, and there is no abnormally water-rich area 2 in the area and the adjacent area, the method of drilling drainage grouting is adopted:

[0085] According to the predicted development height of the water-conducting fracture zone of the burned rock and the occurrence of the aquifer, boreholes (also used as observation holes) are drilled obliquely from two lanes toward the burned rock layer overlying the goaf along the advancing direction of the working face to drain the water between the burned rock fracture layers. The boreholes on one side are arranged at intervals of about 6-10 meters, and the borehole diameter is generally 100-160mm. The borehole depth penetrates the burned rock aquifer. The drainage flow rate and drainage time are determined according to the permeability of the burned rock aquifer, drainage requirements and water volume. When the borehole water pressure is less than 0.1Mpa and the borehole water inflow is less than 100m 3 / h and the hourly change is less than 3%, the drainage is considered complete. During the drainage process, closely observe the drainage volume and water level changes and adjust the drainage parameters in time. According to the characteristics of the burned rock aquifer, the grouting material can be cement slurry, gangue slurry, etc. (The water-cement ratio of cement slurry is generally 0.5:1-1:1, and appropriate amount of water reducer, early strength agent, etc. can be added to improve the performance of slurry; gangue slurry is mixed with gangue, expansion filler and cement slurry, and the slurry sets quickly and has certain toughness) After drainage, first inject expansion filling material into the upper part of the crack (about 1 / 3-2 / 3 of the entire crack height) for preliminary plugging, and 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 amount (the grouting pressure is adjusted according to the permeability of the burned rock aquifer and the degree of crack development, generally 2-4MPa; the grouting flow rate is adjusted according to the grouting pressure and the borehole diameter, generally 40-80L / min), and grouting plugging is performed. During the grouting process, observe the changes in grouting pressure and grouting flow, adjust the grouting parameters, and end the grouting when the grouting pressure reaches the design requirements or the grouting flow rate is significantly reduced.

[0086] (2) When the water-conducting fracture zone 3 touches the burned rock aquifer 1, the affected area 4 is of medium or strong water conductivity, or there is an abnormally water-rich area 2 in the area and the adjacent area, water hazard prevention and control is carried out by means of drilling curtain grouting to cut off the water source: a water-stop curtain is set in advance at the coal mining face, and the two lanes of the working face are excavated in advance. The drilling arrangement parameters are determined according to the model of high-pressure grouting equipment, the slurry diffusion range and the layout of the mining face. The boreholes are arranged in a circular close arrangement method with a radius of about 10-14m. The borehole diameter is 0.8-1.2m and is perpendicular to the rock layer to ensure the grouting effect. The boreholes are drilled into the burned lava layer with more pores and fractures at the bottom of the aquifer (the curtain line is set at the bedrock bottom 5m below the burned rock aquifer). According to the characteristics of the burned lava rock at the bottom of the burned rock, the grouting material can be selected from ultra-fine cement slurry, water glass-slag powder-cement grouting material, etc. Using the high-pressure rotary jet grouting method, the grouting pipe is inserted into the borehole. The diameter and length of the grouting pipe are determined according to the grouting pressure and grouting volume. The high-pressure rotary jet grouting quickly fills the pores. The grouting of each borehole is interconnected to cut off the water source and form a water-stop curtain. During the grouting process, the changes in grouting pressure and grouting flow are observed, and the grouting parameters are adjusted. When the grouting pressure reaches the design requirements or the pressure growth rate of the upper part of the curtain is smaller than that of the lower part, the grouting is terminated.

[0087] In this case, the water-conducting fracture zone runs through the burned rock aquifer 1, the affected area 4 has strong water conductivity, and there is an abnormal water-rich area 2. Drilling drainage and curtain grouting are used to prevent and control water hazards.

[0088] The burned rock aquifer in the water-conducting fracture zone was re-explored: geophysical exploration methods, water exploration and release tests, water pressure tests, and core observations were used to explore the burned rock aquifer 1 and the water-rich abnormal area 2 again, and the physical and mechanical parameters such as the water permeability and permeability of the grouting curtain rock layer were measured to evaluate the water-conducting characteristics of the burned rock aquifer. The qualified requirements for the water-draining effect test: the water conductivity of the burned rock aquifer in the mining-affected area 4 is reduced to weak or below, and the scope of the water-rich abnormal area 2 in and near it is reduced by more than 70%; the water pressure in the water exploration and release test hole is less than the water pressure in the hole by less than 0.1Mpa, the water inflow in the hole is less than 100m3 / h, and the hourly change is less than 3%. The qualified requirements for the grouting effect test: a grouting curtain rock layer is formed at the bottom of the burned rock aquifer in the core, and its physical and mechanical properties meet the requirements of the water blocking isolation layer. It shows that the water-stopping measures in the project meet the design requirements, the permeability of the overlying burned rock is significantly reduced, and the water hazard prevention and control of the burned rock aquifer has achieved results.

[0089] The present invention provides a design method for water hazard prevention and control of a burned rock aquifer. There are many methods and ways to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A design method for water hazard prevention and control of burned rock aquifers, characterized in that: The following steps are involved: Step 1: Explore the geological and hydrogeological conditions of the mine, determine the distribution characteristics of the burned rock, the range of the aquifer and the abnormally rich water area, and build a system for evaluating the water conductivity characteristics of the burned rock aquifer; Step 2, based on the residual expansion coefficient of the burned rock, the calculation formula for the height of the water-conducting fracture zone in the burned rock layer is corrected; Step 3, constructing a burnt rock aquifer risk assessment system based on the relationship between the burnt rock aquifer layer and the height of the water-conducting fracture zone; Step 4: Establish a stratified management method for the burned rock aquifer by interception, drainage and construction based on the risk assessment system; Step 5: Conduct secondary exploration of the burned rock aquifer in the water-conducting fracture zone to test the prevention and control effect.

2. The method according to claim 1, characterized in that In step 1, three-exploration technology and physical and chemical properties of coal and rock samples are used to obtain the spatial characteristics and water-rich characteristics of the strata in the burned area. According to the diagenetic morphology and mineral component characteristics, the diagenetic temperature of the burned rock is inferred, the burned rock types are classified, and a geological model of the burned rock aquifer is established. A water conductivity evaluation system for the burned rock aquifer is proposed to achieve a safe assessment of mining risks. Obtain rock samples from underground rock formations through drilling, analyze the thickness, distribution and grade of the burned rock and other stratified coal rock bodies, as well as the mineral composition, color and structure, determine the distribution range of the burned rock, and divide the thickness and distribution of the aquifer; Geological radar is used to detect underground structures and anomalies through feedback information, improve the resolution of underground imaging, and obtain geological data, including topography, geological structure, ore body distribution, mineral type, average thickness of burned rock layer, etc. r , the burial depth of baked rock is h1, the burial depth of sintered rock is h2 and the burial depth of burned lava rock is h3; Set up hydrological observation wells to monitor groundwater level, flow and water quality; Combine geological and hydrological data to establish a hydrogeological model, simulate the flow and distribution of groundwater, and analyze the flow direction and speed of groundwater; conduct pumping tests and recharge tests to determine the conductivity and water storage capacity of the aquifer; monitor water level changes at different depths and analyze the impact of hydrogeological conditions on the conductivity of the aquifer; Through the above methods, the geological and hydrogeological conditions of the mine were explored, the burned rock area, the aquifer range and the water-rich abnormal area were determined, and the average thickness of the aquifer h was obtained. w .

3. The method according to claim 2, characterized in that In step 1, water pressure test and pumping test are carried out on the rock samples of different layers in the burnt rock layer, and it is measured that the rock samples of the burnt rock layer have the strongest permeability. When the permeability coefficient is greater than 11.5Lu, the unit water yield of the borehole is between 0.2 and 0.6L / s·m, and the porosity exceeds 20% under the storage confining pressure, and the water conductivity of the burnt rock layer is relatively strong; The permeability and water conductivity of sintered rock samples depend on the degree of sintering, which is between sintered rock and baked rock. The permeability of baked rock samples is the weakest. When the permeability coefficient is less than 1Lu, the unit water inflow of the borehole is less than 0.1L / s·m, and the porosity is less than 10% under the confining pressure. The water conductivity of baked rock is poor. The permeability coefficient of burned rock is 10 -7 ~10 2 Between cm / s; Considering the relationship between the aquifer and different types of burned rock layers, the permeability coefficient K and hydraulic conductivity T are used as comprehensive evaluation criteria, where T = 864 × K × h w According to the test results, the characteristics of the burned rock layer and the burned rock aquifer layer, a system for judging the water conductivity characteristics of the burned rock aquifer is constructed: The permeability coefficient K satisfies K≥(10 -3 ~10 2 ), hydraulic conductivity T satisfies T≥10 -3 , the water conductivity index of the aquifer is strong water conductivity; The permeability coefficient K satisfies 10 -4 <K<10 -3 , hydraulic conductivity T satisfies 10 -3 <T<10 -5 , the water conductivity index of the aquifer is medium water conductivity; The permeability coefficient K satisfies K≤(10 -4 ~10 -7 ), hydraulic conductivity T satisfies T≤10 -5 , the water conductivity index of the aquifer is weak water conductivity.

4. The method according to claim 3, characterized in that In step 2, the height of the water-conducting fracture zone in the overlying burned rock strata over the working face mining is estimated. The empirical formula summarized in the mining area, computer numerical simulation, physical similarity simulation test, comprehensive geophysical prospecting technology, ground nuclear magnetic resonance and field observation methods are used to comprehensively predict the height of the water-conducting fracture zone in the overlying burned rock mining. Combined with the classification characteristics of burned rocks, the height of the water-conducting fracture zone in the overlying burned rock mining over the working face mining is predicted. The specific calculation formula is as follows: where h s is the height of the water-conducting fracture zone; η is the sinking coefficient of the burned rock layer; m is the thickness of the coal seam; K t is the limiting curvature of the burned rock layer above the water-conducting fracture zone, and β is the movement angle of the overlying burned rock layer; It is the mining angle of the overlying burned rock strata.

5. The method according to claim 4, characterized in that Step 2 also includes: after the coal seam is mined, the upper burned rock layer sinks. Due to the crushing and swelling of the rock, η considers the height of the upper rock layer in the water-conducting fracture zone to crack and swell, which is related to the residual crushing and swelling coefficient of the rock: Δ=m-(H-h o )(k-1)cosα Among them, among the three types of burned rocks, baked rock is numbered 1, sintered rock is numbered 2, and burned lava rock is numbered 3; Δ is the falling height of the burned rock layer; k is the residual expansion coefficient of the rock, k1 is the residual expansion coefficient of the baked rock, k2 is the residual expansion coefficient of the sintered rock, and k3 is the residual expansion coefficient of the burned lava rock; H is the burial depth of the mined coal seam; h o is the burial depth of the burned rock layer above the water-conducting fracture zone; h1 is the burial depth of the baked rock, h2 is the burial depth of the sintered rock, and h3 is the burial depth of the burned lava rock; l is the exposed length of the burned rock layer; r is the influence radius of the burned rock layer above the water-conducting fracture zone; α is the inclination angle of the coal seam; When h1≥h0>(h3-h r ), the water-conducting fracture zone develops to the baked rock layer in the burned rock layer, and the calculation formula for the falling height Δ of the burned rock layer is: Δ=m-(H-h o )(k1-1)cosα When h2≥h0>h1, the water-conducting fracture zone develops to the sintered rock layer in the burned rock layer, and the calculation formula for the falling height Δ of the burned rock layer is: Δ=m-(H-h o )(k2-1)cosα When h3≥h0>h2, the water-conducting fracture zone develops to the burned rock layer and the lava layer, and the calculation formula for the falling height Δ of the burned rock layer is: Δ=m-(H-h o )(k3-1)cosα The calculation formula for the height of the water-conducting fracture zone in the overlying burned rock during mining of the working face is: Where i=1, 2, 3.

6. The method according to claim 5, characterized in that Step 3 includes: constructing a burnt rock aquifer risk assessment system based on the distribution of burnt rocks, aquifers and water-rich anomalies, the height of the burnt rock fracture zone overlying the working face mining, and the assessment system of the water conductivity characteristics of the burnt rock aquifer: If the height of the water-conducting fracture zone is less than the height of the burned rock aquifer, h s ≤(h r +mh w ), no prevention or treatment is required; If the height of the water-conducting fracture zone is greater than the height of the burned rock aquifer, h s ≥(h r +mh w ), the affected area is weakly water-conductive, and there is no abnormally water-rich area in or near the area, and drilling and drainage grouting is performed; If the height of the water-conducting fracture zone is greater than the height of the burned rock aquifer, h s ≥(h r +mh w ), the affected area is of medium or strong water conductivity, or there are abnormally water-rich areas in and near the area, and curtain grouting is used to drain water.

7. The method according to claim 6, characterized in that Step 4 includes: the method for layered management of the cut-off, dredging and building burnt rock aquifer specifically includes: The burned rock aquifer in the water-conducting fracture zone is weakly conductive: along the advancing direction of the working face, holes are drilled obliquely toward the burned rock layer overlying the goaf from the two lanes to drain water and grout to seal it; during the grouting process, the changes in grouting pressure and grouting flow are observed, and the grouting parameters are adjusted. When the grouting pressure reaches the design requirements or the grouting flow is reduced by 55-65% compared with the initial flow, the grouting is terminated; The burned rock aquifer in the water-conducting fracture zone has medium or strong water conductivity: a water-stop curtain is set in advance at the coal mining face, and the two tunnels of the working face are excavated in advance. The drilling layout parameters are determined according to the model of high-pressure grouting equipment, the slurry diffusion range and the layout of the mining face, and holes are drilled into the burned lava layer with more pores and fractures in the lower part of the aquifer; the high-pressure rotary jet grouting method is used to make the grouting of each borehole conduct to each other to cut off the water source and form a water-stop curtain.

8. The method according to claim 7, characterized in that Step 4 includes using geophysical exploration methods, water exploration and release tests, water pressure tests and core observations to re-explore the burned rock aquifer and the abnormally rich water area, measure the water permeability and permeability of the grouting curtain rock layer, and determine the water conductivity characteristics of the burned rock aquifer; The following conditions must be met to meet the hydrophobic effect test requirements: The first condition is that the water conductivity of the burned rock aquifer in the mining-affected area is reduced to weak or below; The second condition is that the water pressure in the water exploration and drainage test hole is less than 0.1MPa and the water inflow in the hole is less than 100m 3 / h and the hourly change is less than 3%; The third condition is that the area of ​​the nearby water-rich anomaly area is reduced by more than 70%; Among them, the third condition must be met, and either the first or the second condition must be met; Qualified requirements for grouting effect detection: A grouting curtain rock layer is formed at the bottom of the burned rock aquifer in the core, and its physical and mechanical properties meet the requirements of the water blocking isolation layer.

9. An electronic device, characterized in that: The method comprises a processor and a memory, wherein the memory stores program codes, and when the program codes are executed by the processor, the processor executes the steps of the method according to any one of claims 1 to 8.

10. A storage medium, characterized in that: A computer program or instruction is stored, and when the computer program or instruction is run on a computer, the steps of the method according to any one of claims 1 to 8 are executed.

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