Rapid plugging method for coal mine floor drill hole water inrush

Abstract

The invention discloses a quick plugging method for coal mine floor drill hole water inrush, and belongs to the technical field of coal mine water disaster prevention and control. According to the method, the mode of combining long holes and short holes is adopted, the high-pressure grouting technology is adopted, the plugging material specially prepared according to the water inrush condition is prepared, and rapid and accurate plugging of the water inrush point is achieved; comprising the following steps: 1, drilling and positioning; 2, detecting a water inrush point; 3, preparing a plugging material; fourthly, high-pressure grouting is conducted; and 5, monitoring and evaluating the plugging effect. The method mainly aims at eliminating water leakage points of the bottom plate and blocking ordovician limestone hole gushing water, firstly, the short hole is adopted for blocking and treating the area, with the large water leakage amount, of the bottom plate, then the long hole is adopted for conducting full-hole blocking on the ordovician limestone drainage hole, and bottom plate gushing water is treated in a staged and step-by-step mode.

Description

Technical Field

[0001] The invention relates to the technical field of coal mine water hazard prevention and control, in particular to a method for quickly blocking water inrush from a coal mine floor drill hole, and belongs to the technical field of mining. Background Art

[0002] Water inrush from coal mine floor drilling is a common water hazard during coal mining, posing a serious threat to coal mine safety production. During coal mining, floor heaving and water seepage are common underground. Furthermore, once the hydrogeological boreholes underground are damaged by ground stress or corroded by acidic water, abnormal water discharge from the boreholes requires rapid disposal. This is especially true for "hydrogeological boreholes" located at the intersections of tunnels, such as connecting lanes. Regional stratum stress changes, and the mine pressure becomes apparent, leading to floor heaving, ground fissures, and top and side slurry shedding. The impact of the floor mine pressure damages the casing of the Ordovician ash drainage hole, causing the Ordovician ash water in the hole to leak out along the cracks in the floor strata. Traditional plugging methods suffer from slow plugging speeds and unstable results, making it difficult to meet the needs of rapid emergency response. Therefore, an efficient and rapid plugging method is urgently needed to solve the above problems.

[0003] Based on this, combined with the mine geological data and geophysical data, this design plan was formulated to control the bottom water inrush in stages and steps. Summary of the Invention

[0004] This invention aims to provide a method for rapidly sealing water inrush from drill holes in coal mine floors, managing water inrush in stages and steps. This method utilizes a combination of long and short holes, high-pressure grouting technology, and a specially formulated sealing material to achieve rapid and precise sealing of water inrush points.

[0005] The present invention provides a method for quickly blocking water inrush from a coal mine floor drill hole, comprising the following steps: The first step is drilling positioning: Determine the location of the water burst drilling hole: adopt a combination of long holes and short holes; The second step is to detect the water burst point: Accurately locate the water burst point and seal it with short holes first. The design plan of the short holes is as follows: Based on the on-site water outlet point, within 1-5m around the water outlet point, determine the horizontal and vertical drilling layout in the form of plum blossom or circular equal division, combined with the bottom plate damage depth.

[0006] The third step is to prepare the plugging materials: After the short holes are plugged, the long holes are ready for grouting and plugging, and the plugging materials need to be prepared in advance. The present invention specially prepares the plugging materials for the water inrush situation, and adds water glass to the existing cement slurry or chemical slurry. Step 4: High-pressure grouting: Carry out high-pressure grouting and sealing, and control the pressure at 2-5MPa.

[0007] Step 5: Monitoring and evaluation of plugging effects: Monitor the plugging effect and determine whether it meets the standard: if it meets the standard, the process ends; if it does not meet the standard, return to the high-pressure grouting step until the plugging effect meets the standard, that is, the plugging is successful and the process ends.

[0008] The above-mentioned method of first plugging the short hole is: (1) First, treat the area with the largest amount of water leakage in the baseboard, and then check for any deficiencies, repair any leaks, and strengthen the sealing according to the treatment situation.

[0009] (2) Construction sequence and coverage: With the Aohui drainage hole as the center, draw a circle with a radius of 0.5m to 3.5m, and make several concentric circles with an interval of 1m. Short holes are evenly arranged with an interval of 1m on the circumference of each circle. The construction sequence is from the outer perimeter to the inner perimeter. During construction, long wooden boards are placed under the feet to prevent local collapse and injury. The drilling location and hole depth can be slightly adjusted according to the actual situation on site.

[0010] (3) During the short hole grouting process, double-liquid slurry is selected.

[0011] Specifically, a total of 1 drilling site was arranged, 40 short holes of 2m in length were designed, with a total footage of 80m, an inclination of -90°, a hole diameter of 42-48mm, and a grouting steel pipe length of 1m; the amount of double-liquid slurry injected per meter was 0.2m 3 .

[0012] The double-liquid slurry is composed of cement slurry and water glass in a mass ratio of 1:0.4.

[0013] The above-mentioned operation method for long hole grouting is: according to the water situation of the leaking point, the whole hole of the Aohui drainage hole is sealed. Usually, due to the water gushing from the drilling hole exceeding 1m 3 / hour, with pressure and high water volume, this is considered live water grouting. Depending on the water output, anchor cables and aluminum-plastic pipes are used to drill through the hole. To ensure project quality, a drilling rig is used to sweep the entire hole. After sweeping, grouting is performed. A grouting valve or grouting pad is temporarily placed 80 meters below the borehole mouth to seal the hole. Then, a double-liquid grout is injected to densely seal the hole.

[0014] The selection of grouting materials is crucial in this invention. The grouting materials consist of a base grout and a CSA additive, with the CSA additive accounting for 5%-30% of the grouting material by mass. The grouting materials should be appropriately and effectively formulated based on the geological conditions of the region. Taking into account the grouting characteristics, the base grout can include one of ordinary cement grout, chemical grout, or cement-water glass blend. Furthermore, the chemical grout can be a mixture of one or more of water glass, acrylamide, chromium lignin, urea-formaldehyde resin, polyurethane, furfural resin, and epoxy resin.

[0015] The properties of slurry are very important for grouting projects. Only by selecting slurry with appropriate properties can the actual grouting purpose be achieved. If the slurry is not selected properly, it will be difficult to inject the slurry or the slurry will be lost or the strength will be very low, then the purpose of grouting cannot be achieved. Therefore, when comparing the main characteristic parameters of the slurry, the following parameters need to be considered: (1) the density and weight of the slurry; (2) the concentration of the slurry; (3) the pH value of the slurry; (4) the viscosity of the slurry; (5) the gel time of the slurry; and (6) the injectability and permeability of the slurry.

[0016] The CSA additive has a chemical formula of 3CaO·3Al2O3·CaSO4. This material exhibits excellent expansion properties in the slurry, effectively improving the density and impermeability of the grout. Expansion properties: During hydration, CSA forms 3CaO·Al2O3·3CaSO4·32H2O, a mineral with significant expansion properties that can compensate for shrinkage during the hardening process of the grout.

[0017] To achieve good grouting effects, the slurry is required to have two characteristics at the same time: first, the slurry is required to maintain good fluidity during the pumpable period and the viscosity does not increase much. This is the so-called injectability, which is conducive to the full injection of the slurry into pores and cracks; second, the slurry viscosity is required to increase rapidly after the pumpable period, and the time interval from the pumpable period to the initial and final setting is short, that is, the slurry should have good controllability. This characteristic is conducive to the slurry bonding rock and soil, and prevents the slurry from being eroded by groundwater before solidification.

[0018] When water volume is less than 5m 3 / h, chemical slurry can be used to seal micro cracks first, and then single cement slurry or double liquid slurry can be injected; if the water volume is greater than 5m 3 / h, first use cement single-liquid slurry, then use cement-water glass double-liquid slurry.

[0019] After selecting the slurry materials, the following procedures should be followed before mixing: 1) Addition order and stirring time: Clean water → cement (>2 min) → CSA additive (>3 min).

[0020] 2) Quantity of materials added per tank: Calculate the amount of various materials according to the corresponding ratio and volume of each tank. You can refer to the slurry ratio classification table and add 5%-30% CSA additives.

[0021] 3) After the slurry is prepared, it must be used up within 2 hours. Slurry that is more than 2 hours old must not be used in grouting projects.

[0022] Since cement slurry has shrinkage, if necessary, consider re-injecting chemical slurry, and the design and construction must be based on the results of the first grouting.

[0023] The relevant process requirements in the above grouting process are further explained as follows: (1) A water pressure test should be conducted before each grouting and after each grouting section. During the water pressure test, the flow rate is gradually increased from a low level to a pressure of 1.5 times the hydrostatic pressure. The water pressure test should be conducted for 30 minutes to maintain a stable pressure and flow rate. The pressure of this water pressure test is 4.0 MPa.

[0024] The water pressure test uses a grouting pump to press water into the grouting section at a certain water pressure through the pipeline system. The main purposes are: ① Check the grouting stop pipe head and pay special attention to the grouting stop effect of the grouting stop plug.

[0025] ② Push the debris that has not been flushed out and remains at the bottom of the hole or is stuck on the hole wall out of the grouting range to improve the strength and impermeability of the slurry stone body.

[0026] ③ According to the measured borehole water absorption, verify the permeability of the soil layer to determine the pumping volume and pump pressure of the grouting pump and decide the initial concentration of single-liquid slurry or double-liquid slurry.

[0027] ④ Comprehensively analyze the hydrogeological characteristics of the rock formation (such as static water level, permeability, connectivity, and degree of fracture development) based on pressure, flow rate, and water pressure section height. During the water pressure test during grouting, the focus is on analyzing changes in fractures and porosity in the injected formation, and thus analyzing the grouting effect.

[0028] (2) Grouting pressure is the driving force for the diffusion of slurry in coal (rock) strata. Grouting pressure directly affects the effect of grouting reinforcement, but grouting pressure is also affected and restricted by factors such as the geological conditions of the grouting stratum, grouting materials, and grouting methods. High grouting pressure is conducive to better injection of slurry into the stratum, increasing the diffusion range of slurry, and enabling faster and more precipitation of water in the stratum, making the stone dense and full. If the grouting pressure is too high, the slurry will be excessively veined and wasted. The selection of grouting pressure should comprehensively consider factors such as the burial depth, porosity, and hydrostatic pressure of the coal (rock) stratum. For the calculation of grouting pressure, based on the burial depth of the stratum, surface water flow, etc., the hydrostatic pressure of this grouting pressure is temporarily taken as 1MPa, and the maximum pressure at the grouting hole is 2.0~2.5MPa. The final hole pressure is 2.5MPa.

[0029] (3) Calculation of grouting volume The single hole slurry injection volume can be calculated as follows: Q=AπR 2 Lßη Where: Q is the grouting volume of a single hole, m 3 ; A—grouting loss coefficient, taken as 0.9; π—pi, take 3.14; R—effective diffusion radius, which varies from stratum to stratum and requires geological report; L—grouting hole length, unit is 1m; η—crack ratio, taken as 0.01; ß—slurry filling coefficient, taken as 0.8; During on-site construction, the layout of individual grouting holes, slurry replacement and proportioning must be adjusted according to the actual project conditions, so the actual final material consumption will vary.

[0030] (4) Adjustment of grouting parameters 1) Prepare slurry according to water output; Water output <5m 3 / h, the water-cement ratio is controlled to be 1.4~5:1, and the slurry density is 1.13~1.39t / m 3 1 ton of cement is used to prepare slurry of 1.44~5.32m 3 ; Water output>5m 3 / h, the water-cement ratio is controlled to be 0.5~1:1, and the slurry density is 1.50~1.83t / m 3 1 ton of cement is used to prepare slurry of 0.82~1.33m 3 ; 2) When grouting begins, you should first use thin slurry and low pressure (use a slurry with a water-cement ratio of 2:1, and change the water-cement ratio to 1:1 for grouting after the pressure rises). Record the changes in pressure, concentration, and flow at any time, and then adjust the grouting water-cement ratio parameters step by step accordingly.

[0031] 3) The adjustment principles are as follows: ① After 30 minutes of grouting with a fixed pressure and concentration of slurry, if the orifice pressure changes slightly and the slurry suction volume gradually decreases, or the slurry suction volume remains basically unchanged and the orifice pressure rises slowly, it means that the grouting pressure, slurry concentration, etc. are relatively appropriate and the parameters should not be changed.

[0032] ② After 30 minutes of grouting with a fixed pressure and concentration, if the orifice pressure gradually increases and the grouting volume gradually decreases, or even if the orifice pressure increases sharply or the grouting volume decreases significantly, it indicates that the slurry concentration is too high and should be diluted one level in time. Otherwise, the grouting pressure should be increased and the slurry gradation should be improved.

[0033] ③ When pouring according to the slurry concentration prepared for the first time, if the slurry absorption volume in the hole is small (<1~2L / min) for 15 minutes, the slurry can be diluted and the pressure can be increased.

[0034] 4) The injection volume of thin slurry should be 30% of the single-hole grouting volume.

[0035] (5) Judgment criteria for the end of grouting For the grouting process itself, the grouting volume and final grouting pressure are used as the standard for completing the grouting of a single hole. The standard for completing the grouting is to meet any of the following conditions: 1) The pressure at the grouting pipe nozzle rises to above 0.5 MPa and remains stable for 15 minutes; 2) The pressure at the grouting pipe nozzle does not rise to 0.5 MPa, but the slurry flow rate is less than 70 L / min and lasts for 15 minutes; 3) The slurry overflows from the highest point of the cavity.

[0036] Beneficial effects of the present invention: The present invention provides a method for quickly sealing water inrush from coal mine floor drilling holes, which mainly focuses on eliminating water leakage points in the floor and sealing water gushing from Ordovician ash holes. First, short holes are used to seal the areas with large water leakage in the floor, and then long holes are used to seal the entire Ordovician ash discharge holes, thereby achieving staged and step-by-step treatment of water inrush from the floor. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Flow chart for rapid plugging of water inrush boreholes; Figure 2 Schematic diagram of drilling construction location for short hole plugging; Figure 3 Schematic diagram of grouting holes for long hole grouting plugging; In the figure, 1 is the grouting hole, 2 is the water glass slurry delivery pipe, 3 is the cement slurry slurry delivery pipe, 4 is the single liquid slurry slurry delivery pipe, 5 is the orifice blowout preventer, 6 is the three-pronged mixer, and 7 is the slurry stop pad. DETAILED DESCRIPTION

[0038] The present invention is further illustrated below by way of examples, but is not limited to the following examples. Example

[0039] This embodiment provides a method for quickly blocking water inrush from a drilling hole in a coal mine floor. The process is as follows: Figure 1 As shown, the specific steps include: The first step is drilling positioning: Determine the location of the water burst drilling hole: adopt a combination of long holes and short holes; The second step is to detect the water burst point: Accurately locate the water burst point and seal it with short holes first. The design plan of the short holes is as follows: Based on the on-site water outlet point, within 1-5m around the water outlet point, determine the horizontal and vertical drilling layout in the form of plum blossom or circular equal division, combined with the bottom plate damage depth.

[0040] The third step is to prepare the plugging materials: After the short holes are plugged, the long holes are ready for grouting. The plugging materials need to be prepared in advance. The present invention specially prepares the plugging materials for water inrush, adding calcium sulfoaluminate (CSA) to the cement slurry. Step 4: High-pressure grouting: Perform high-pressure grouting to seal. First use thin slurry and low pressure (use slurry with a water-cement ratio of 2:1, and after the pressure rises, change the water-cement ratio to 1:1 for grouting). Step 5: Monitoring and evaluation of plugging effects: Monitor the plugging effects and determine whether they meet the standards. If the standard is met, the process ends; if the standard is not met, return to the high-pressure grouting step until the plugging effect meets the standard, that is, the plugging is successful and the process ends.

[0041] The above-mentioned operation method of first short hole plugging is: (1) First, treat the area with the largest amount of water leakage in the baseboard, and then check for any deficiencies, repair any leaks, and strengthen the sealing according to the treatment situation.

[0042] (2) Construction sequence and coverage: With the Aohui drainage hole as the center, draw a circle with radii of 0.5m, 1.5m, 2.5m, and 3.5m, and arrange a drill hole every 1m on the circumference. The construction sequence is from the outer perimeter to the inner perimeter. During construction, long wooden boards are placed under the feet to prevent local collapse and injury. The drilling construction position and hole depth can be slightly adjusted according to the actual situation on site. Figure 2 shown.

[0043] (3) Design engineering quantity: ① One drilling site was arranged. 40 short holes of 2 m in length were drilled, with a total footage of 80 m, an inclination of -90°, a hole diameter of 42-48 mm, and a grouting steel pipe length of 1 m (see Table 1).

[0044] ② Short hole grouting volume: Use double liquid slurry (cement slurry: water glass = 1:0.4 ratio), and inject 0.2m per meter of double liquid slurry. 3 , totaling 16.0m 3 .

[0045] Table 1 Short hole design parameters

[0046] The above-mentioned operation method of post-long hole grouting and plugging is: Based on the water flow from the leaking point, the entire Aohui drainage hole is sealed. Typically, due to the high water flow and pressure from the borehole exceeding 1m³ / hour, this is a case of live water grouting. Based on the water flow, anchor cables and aluminum-plastic pipes are used to drill through the hole. If there are significant obstructions at least two locations within 3-6m of the hole, preventing further drilling, a full borehole sweep is performed using a drilling rig to ensure project quality. After sweeping, grouting is performed. A grout stop valve or grout stop pad is temporarily sealed 80m below the borehole mouth (108mm casing is lowered to a depth of 79m). Then, a double-liquid slurry is injected to seal the hole densely.

[0047] Structural design of grouting holes (such as Figure 3 As shown in the figure, a water glass grouting pipe 2, a cement slurry pipe 3, and a single-liquid slurry pipe 4 (also serving as a pressure relief pipe) are installed within the grouting hole 1. A blowout preventer 5 is installed at the top end of the hole. A three-pronged mixer 6 is connected to the bottom of the grouting pipe, and a grout stop pad 7 is installed at the bottom of the three-pronged mixer 6. In this embodiment, two φ19mm grouting pipes are lowered into the hole at 80m, and two 4' (or 6') steel pipes, each 2m long, are lowered into the hole at 90m. A 0.5m three-pronged mixer is used at the bottom of the φ19mm grouting pipe to mix the water glass and cement slurry. A grout stop pad is installed at the bottom of the three-pronged mixer. If the resistance in the hole is high, a counterweight can be placed at the bottom of the three-pronged mixer. The third grouting pipe is used to relieve pressure and observe grouting. When the main pipe stops flowing and grouting is stopped, the third grouting pipe uses single-liquid slurry to fill the area below the plugged section until the final grouting pressure is reached. Static pressure is used to displace water accumulated from the orifice to the plugged section above the plugged section.

[0048] The selection of grouting materials in the long hole grouting and plugging process is shown in Tables 2 to 5 below. The selection of grouting materials in the present invention is particularly important. It is composed of a base slurry body and a CSA additive, wherein the mass ratio of the CSA additive is 5%-30%. The slurry should be reasonably and effectively matched according to the geological conditions of the area.

[0049] Only by selecting slurry with appropriate performance can the actual grouting purpose be achieved. If the slurry is not selected properly, the slurry is difficult to inject or the slurry is lost or the strength is very low, the purpose of grouting cannot be achieved. Therefore, the main characteristic parameters of the slurry need to be compared, and the following parameters need to be considered: (1) density and specific gravity of the slurry; (2) concentration of the slurry; (3) pH value of the slurry; (4) viscosity of the slurry; (5) gel time of the slurry; (6) injection capacity and permeability of the slurry, as shown in Tables 2 to 5 below.

[0050] Table 2 Viscosity of commonly used grouting materials and their measurement methods

[0051] The gel (coagulation) time of several commonly used slurries is shown in Table 3.

[0052] Table 3 Grouting slurry gel (setting) time

[0053] Table 4 Permeability of commonly used grouting materials Table 5 Permeability coefficients of consolidation bodies of commonly used grouting materials

[0054] The CSA additive has a chemical formula of 3CaO·3Al2O3·CaSO4. This material exhibits excellent expansion properties in the slurry, effectively improving the density and impermeability of the grout. Expansion properties: During hydration, CSA forms 3CaO·Al2O3·3CaSO4·32H2O, a mineral with significant expansion properties that can compensate for shrinkage during the hardening process of the grout.

[0055] In order to facilitate operation and accurately control grouting parameters, the slurry concentration classification and usage conditions are listed in Table 6 below: Table 6 Cement slurry conversion table

[0056] Note: Water volume < 5m 3 / h, chemical slurry can be used to seal micro cracks first, and then single cement slurry or double liquid slurry can be injected; if the water volume is greater than 5m 3 / h, first use cement single-liquid slurry, then use cement-water glass double-liquid slurry.

[0057] After selecting the slurry materials, the following procedures should be followed before mixing: 1) Sequence and mixing time: Clean water → cement (>2 min) → CSA additive (>3 min).

[0058] 2) Quantity of materials added per tank: Calculate the amount of various materials according to the corresponding ratio and volume of each tank. You can refer to the slurry ratio classification table to add 5%-30% of special materials.

[0059] 3) After the slurry is prepared, it must be used up within 2 hours. Slurry that is more than 2 hours old must not be used in grouting projects.

[0060] Since cement slurry has shrinkage, if necessary, consider re-injecting chemical slurry, and the design and construction must be based on the results of the first grouting.

[0061] The relevant process requirements in the above grouting process are further explained as follows: (1) A water pressure test should be conducted before each grouting and after each grouting section. During the water pressure test, the flow rate is gradually increased from a low level to a pressure of 1.5 times the hydrostatic pressure. The water pressure test should be conducted for 30 minutes to maintain a stable pressure and flow rate. The pressure of this water pressure test is 4.0 MPa.

[0062] The water pressure test uses a grouting pump to press water into the grouting section at a certain water pressure through the pipeline system. The main purposes are: ① Check the grouting stop pipe head and pay special attention to the grouting stop effect of the grouting stop plug.

[0063] ② Push the debris that has not been flushed out and remains at the bottom of the hole or is stuck on the hole wall out of the grouting range to improve the strength and impermeability of the slurry stone body.

[0064] ③ According to the measured borehole water absorption, verify the permeability of the soil layer to determine the pumping volume and pump pressure of the grouting pump and decide the initial concentration of single-liquid slurry or double-liquid slurry.

[0065] ④ Comprehensively analyze the hydrogeological characteristics of the rock formation (such as static water level, permeability, connectivity, and degree of fracture development) based on pressure, flow rate, and water pressure section height. During the water pressure test during grouting, the focus is on analyzing changes in fractures and porosity in the injected formation, and thus analyzing the grouting effect.

[0066] (2) Grouting pressure is the driving force for the diffusion of slurry in coal (rock) strata. Grouting pressure directly affects the effect of grouting reinforcement, but grouting pressure is also affected and restricted by factors such as the geological conditions of the grouting stratum, grouting materials, and grouting methods. High grouting pressure is conducive to better injection of slurry into the stratum, increasing the diffusion range of slurry, and enabling faster and more precipitation of water in the stratum, making the stone dense and full. If the grouting pressure is too high, the slurry will be excessively veined and wasted. The selection of grouting pressure should comprehensively consider factors such as the burial depth, porosity, and hydrostatic pressure of the coal (rock) stratum. For the calculation of grouting pressure, based on the burial depth of the stratum, surface water flow, etc., the hydrostatic pressure of this grouting pressure is temporarily taken as 1MPa, and the maximum pressure at the grouting hole is 2.0~2.5MPa. The final hole pressure is 2.5MPa.

[0067] (3) Calculation of grouting volume The single hole slurry injection volume can be calculated as follows: Q=AπR 2 Lßη Where: Q is the grouting volume of a single hole, m 3 ; A—grouting loss coefficient, taken as 0.9; π—pi, take 3.14; R—effective diffusion radius, the crack diffusion radius is 10m; L—grouting hole length, unit is 1m; η—crack ratio, taken as 0.01; ß—slurry filling coefficient, taken as 0.8; During on-site construction, the layout of individual grouting holes, slurry replacement and proportioning must be adjusted according to the actual project conditions, so the actual final material consumption will vary.

[0068] (4) Adjustment of grouting parameters 1) Prepare the slurry according to the water output, see Table 2-5.

[0069] Water output <5m 3 / h, the water-cement ratio is controlled to be 1.4~5:1, and the slurry density is 1.13~1.39t / m 3 1 ton of cement is used to prepare slurry of 1.44~5.32m 3 ; Water output>5m 3 / h, the water-cement ratio is controlled to be 0.5~1:1, and the slurry density is 1.50~1.83t / m 3 1 ton of cement is used to prepare slurry of 0.82~1.33m 3 ; 2) When grouting begins, you should first use thin slurry and low pressure (use a slurry with a water-cement ratio of 2:1, and change the water-cement ratio to 1:1 for grouting after the pressure rises). Record the changes in pressure, concentration, and flow at any time, and then adjust the grouting water-cement ratio parameters step by step according to the actual situation (water-cement ratio needs to be adjusted).

[0070] 3) The adjustment principles are as follows: ① After 30 minutes of grouting with a fixed pressure and concentration of slurry, if the orifice pressure changes slightly and the slurry suction volume gradually decreases, or the slurry suction volume remains basically unchanged and the orifice pressure rises slowly, it means that the grouting pressure, slurry concentration, etc. are relatively appropriate and the parameters should not be changed.

[0071] ② After 30 minutes of grouting with a fixed pressure and concentration, if the orifice pressure gradually increases and the grouting volume gradually decreases, or even if the orifice pressure increases sharply or the grouting volume decreases significantly, it indicates that the slurry concentration is too high and should be diluted one level in time. Otherwise, the grouting pressure should be increased and the slurry gradation should be improved.

[0072] ③ When pouring according to the slurry concentration prepared for the first time, if the slurry absorption volume in the hole is small (<1~2L / min) for 15 minutes, the slurry can be diluted and the pressure can be increased.

[0073] 4) The injection volume of thin slurry should be 30% of the single-hole grouting volume.

[0074] (5) Judgment criteria for the end of grouting For the grouting process itself, the grouting volume and final grouting pressure are used as the standards for completing the grouting of a single hole. The standard for completing the grouting is to meet any one of the following three conditions: 1) The pressure at the grouting pipe nozzle rises to above 0.5 MPa and remains stable for 15 minutes; 2) The pressure at the grouting pipe nozzle does not rise to 0.5 MPa, but the slurry flow rate is less than 70 L / min and lasts for 15 minutes; 3) The slurry overflows from the highest point of the cavity.

Claims

1. A method for quickly blocking water inrush from a drilling hole in a coal mine floor, characterized in that The following steps are involved: The first step is drilling positioning: Determine the location of the water burst drilling hole: adopt a combination of long holes and short holes; The second step is to detect the water burst point: Accurately locate the water inrush point and first perform short hole plugging. The design plan for the short holes is as follows: Based on the on-site water outflow point, within a range of 1-5m around the water outflow point, determine the horizontal and vertical drilling layout in the form of a plum blossom or circular even division, combined with the depth of the bottom plate damage; The third step is to prepare the plugging materials: After the short holes are plugged, the long holes are to be plugged by grouting, and the plugging materials need to be prepared in advance; Step 4: High-pressure grouting: Carry out high-pressure grouting and plugging, and control the pressure at 2-5MPa; Step 5: Monitoring and evaluation of plugging effects: Monitor the plugging effect and determine whether it meets the standard: if it meets the standard, the process ends; if it does not meet the standard, return to the high-pressure grouting step until the plugging effect meets the standard, that is, the plugging is successful and the process ends.

2. The method for rapidly blocking water inrush from a coal mine floor drill hole according to claim 1, characterized in that: The operation method for short hole plugging first is: (1) First treat the area with the largest amount of water leakage in the bottom plate, and then check for any defects, repair any leaks, and strengthen the sealing according to the treatment situation; (2) Construction sequence and coverage: With the Aohui drainage hole as the center, draw a circle with a radius of 0.5m to 3.5m, and make several concentric circles at intervals of 1m. Short holes are evenly arranged at intervals of 1m on the circumference of each circle; (3) During the short hole grouting process, double-liquid slurry is selected.

3. The method for rapidly blocking water inrush from a coal mine floor drill hole according to claim 2, characterized in that: A total of 1 drilling site was arranged, 40 short holes of 2m in length were designed, with a total footage of 80m, an inclination of -90°, a hole diameter of 42-48mm, and a grouting steel pipe length of 1m; the amount of double-liquid slurry injected per meter was 0.2m 3 The double-liquid slurry is composed of cement slurry and water glass in a mass ratio of 1:0.

4.

4. The method for rapidly blocking water inrush from a coal mine floor drill hole according to claim 1, characterized in that: The operation method for long hole grouting and plugging is: according to the water output of the leakage point, the Aohui drainage hole is fully sealed, and according to the water output, anchor cables and aluminum-plastic pipes are used to drill through the hole. In order to ensure the quality of the project, a drilling rig is required to sweep the entire hole; after sweeping the hole, grouting is carried out, and the slurry stop valve or slurry stop pad is temporarily sealed 80m below the borehole mouth, and then double-liquid slurry is injected for dense sealing.

5. The method for rapidly blocking water inrush from a coal mine floor drill hole according to claim 1, characterized in that: The grouting material consists of a basic slurry body and a CSA additive, wherein the mass ratio of the CSA additive to the grouting material is 5%-30%; the basic slurry body includes one of ordinary cement slurry, chemical slurry, and cement-water glass mixed slurry, and the chemical slurry is one or a mixture of water glass, acrylamide, chromium lignin, urea-formaldehyde resin, polyurethane, furfural resin, and epoxy resin slurries.

6. The method for rapidly blocking water inrush from a coal mine floor drill hole according to claim 5, characterized in that: The chemical formula of the CSA additive is 3CaO·3Al2O3·CaSO4.

7. The method for rapidly blocking water inrush from a coal mine floor drill hole according to claim 1, characterized in that: When water volume is less than 5m 3 / h, first use chemical slurry to seal micro cracks, then inject single cement slurry or double liquid slurry; water volume is greater than 5m 3 / h, first use cement single-liquid slurry, then use cement-water glass double-liquid slurry.

8. The method for rapidly blocking water inrush from a coal mine floor drill hole according to claim 7, characterized in that: Prepare slurry according to water output: water output < 5m 3 / h, the water-cement ratio is controlled to be 1.4~5:1, and the slurry density is 1.13~1.39t / m 3 1 ton of cement is used to prepare slurry of 1.44~5.32m 3 ; Water output>5m 3 / h, the water-cement ratio is controlled to be 0.5~1:1, and the slurry density is 1.50~1.83t / m 3 1 ton of cement is used to prepare slurry of 0.82~1.33m 3 .

9. The method for rapidly blocking water inrush from a coal mine floor drill hole according to claim 1, characterized in that: When grouting begins, thin slurry and low pressure should be used first, and a slurry with a water-cement ratio of 2:1 should be used for grouting. After the pressure rises, the water-cement ratio should be changed to 1:1 for grouting; the amount of thin slurry injected is 30% of the single-hole grouting volume.

10. The method for rapidly blocking water inrush from a coal mine floor drill hole according to claim 9, characterized in that: After 30 minutes of grouting with a fixed pressure and concentration of slurry, if the orifice pressure changes slightly and the slurry suction volume gradually decreases, or the slurry suction volume remains basically unchanged and the orifice pressure rises slowly, it means that the grouting pressure and slurry concentration are appropriate; After 30 minutes of grouting with a fixed pressure and concentration, if the orifice pressure gradually increases and the grouting volume gradually decreases, or even the orifice pressure increases sharply or the grouting volume decreases significantly, it means that the slurry concentration is too high and should be diluted one level in time. Otherwise, the grouting pressure should be increased and the slurry gradation should be improved. When pouring according to the initially prepared slurry concentration, if the slurry absorption in the hole is less than 1~2L / min for 15 minutes, dilute it and increase the pressure; The final grouting pressure is the standard for ending grouting in a single hole, and any of the following conditions will suffice: ① The pressure at the grouting pipe mouth rises to above 0.5MPa and remains stable for 15 minutes; ② The pressure at the grouting pipe mouth does not rise to 0.5MPa, but the slurry flow rate is less than 70L / min and continues for 15 minutes; ③ The slurry overflows from the highest point of the hole.

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