Method for preventing and treating floor water inrush

Abstract

The invention discloses a method for preventing and controlling floor water inrush in the technical field of mine water disaster prevention and control, which comprises the following steps of: 1, analyzing mine conditions: knowing geological conditions of a water-resisting layer and a water-bearing layer, and determining underground water conditions; 2, regional evaluation: probing the water yield property of the aquifer, and dividing the working face into an abnormal region and a dangerous region; 3, drilling is carried out, wherein hole verification area division is carried out, the water quality type is determined, and the water pressure is measured; 4, drainage and pressure reduction, wherein drainage is conducted in the main hole according to the water inrush coefficient, and meanwhile water pressure and water pumping amount fluctuation are monitored in the whole process; 5, observation holes are formed and monitored, specifically, a plurality of observation holes are additionally formed in one side of the main hole, and water level changes are monitored; sixthly, grouting reinforcement is conducted, specifically, grouting reinforcement is conducted at the main hole, and meanwhile the water pumping power is lowered; and 7, reinforcing result verification: evaluating the reinforcing effect. The method is easy to operate, and the ideal bottom plate reinforcing effect is achieved by conducting drainage pressure reduction and grouting reinforcement at the same time and arranging the observation holes.

Description

Technical Field

[0001] The invention belongs to the technical field of mine water hazard prevention and control, and specifically relates to a method for preventing and controlling bottom plate water inrush. Background Art

[0002] The floor water inrush accident is caused by the floor aquifer with high water pressure suddenly passing through the impermeable rock layer between the mined coal seam and the aquifer and entering the mining space. This kind of water inrush is a complex geological and mining phenomenon, which has both geological and structural reasons and mining work reasons. Analysis shows that the cause of floor water inrush is closely related to the height of the original lifting zone above the aquifer, the depth of the floor fracture zone formed by mining, and the ability of the impermeable rock layer between the two zones to resist the water pressure damage of the lower confined water. The rock mass of the original lifting zone and the floor fracture zone has lost its water-proof performance. If the mining space directly conducts the confined water through the two zones, or if it is not directly connected, but under the action of the confined water pressure, the impermeable protective layer between the two zones will be destroyed, and then develop into a rock mass that conducts confined water, then a water inrush accident will occur in the mining space.

[0003] Due to the complex geological structure conditions in my country, mine water disasters in my country pose a threat to the safety of miners' lives and property, especially mine water inrush disasters, which often cause property losses. Among various types of coal mine water disasters, most major water inrush disasters are caused by the hidden vertical water-conducting structure of the coal seam floor that conducts through the thick and water-rich Ordovician limestone aquifer.

[0004] At present, the main prevention and control technology for the problem of water inrush from the mine floor is the method of grouting reinforcement of the floor waterproof layer. However, due to the existence of groundwater recharge sources in the aquifer, it is rich in water and prone to multiple water inrush paths, resulting in unfavorable factors such as large grouting and water blocking engineering workload and difficulty in subsequent maintenance. Therefore, it is necessary to propose a method for preventing and controlling water inrush from the floor to improve the efficiency of grouting reinforcement of the floor. Summary of the invention

[0005] In order to solve the problem of unsatisfactory bottom plate grouting reinforcement effect, the present invention aims to provide a method for preventing and controlling bottom plate water inrush, which achieves an ideal bottom plate reinforcement effect by simultaneously performing drainage and pressure reduction and grouting reinforcement and arranging observation holes.

[0006] In order to achieve the above object, the technical solution of the present invention is as follows:

[0007] Step 1: Analyze mine conditions: Understand the geological conditions of the aquiclude and aquifer at the mine working face, analyze water filling factors, and clarify groundwater conditions;

[0008] Step 2: Regional evaluation: along the working face, explore the water-richness of the aquifer, identify the hidden faults and water-conducting channels of the floor, and conduct a regional evaluation of the danger of water inrush from the floor, dividing it into abnormal areas and dangerous areas;

[0009] Step 3: Drilling: Drill holes to the aquifer in the dangerous and abnormal areas, verify the rationality of the regional division, observe the water gushing from the boreholes, analyze the water quality of the borehole water samples, compare the water quality analysis data to determine the water quality type, and measure the water pressure;

[0010] Step 4: Drainage and pressure reduction: Based on step 3, calculate the water inrush coefficient of abnormal and dangerous areas. If the water inrush coefficient is less than 0.06MPa / m, keep the borehole as an observation hole. If the water inrush coefficient is greater than 0.06MPa / m, widen the borehole as the main hole, lower the first casing into the main hole, install a water pump to drain and reduce pressure, and monitor the fluctuations of water pressure and pumping volume throughout the drainage process.

[0011] Step 5: Arrange observation holes and monitor: add several observation holes on one side of the main hole to monitor water level changes;

[0012] Step 6: Grouting reinforcement: On the basis of step 4, after the water pressure drops and the water level fluctuation amplitude stabilizes, lower the second casing into the main hole, implement high-pressure grouting reinforcement, and gradually reduce the pumping power of the water pump. After the grouting is completed, stop draining, seal the main hole, and retain the observation hole;

[0013] Step seven, verification of reinforcement results: After the grouting reinforcement is completed, observe the restored water level in the observation hole, and the dryness of the bottom plate during subsequent mining to abnormal and dangerous areas of the bottom plate to evaluate the reinforcement effect.

[0014] Furthermore, in step one, the geological conditions of the aquiclude and the aquifer include the lithology and effective thickness of the aquiclude and the lithology of the aquifer, the water filling factors include atmospheric precipitation, surface water and groundwater, and the groundwater conditions include the source of groundwater recharge, runoff pathways and discharge pathways.

[0015] Furthermore, in step 2, when exploring the aquifer, ground transient electromagnetic exploration technology is used, and the test line is selected according to the groundwater conditions to obtain the resistivity cross-section diagram of the test line. The resistivity is inversely proportional to the water richness.

[0016] Further, in step three, the borehole water quality analysis includes calcium ion content, pH value, bicarbonate ion content, sulfate ion content, hardness and suspended matter.

[0017] Furthermore, in step 4, the water inrush coefficient is the ratio of the hydrostatic pressure in the aquifer to the thickness of the aquiclude.

[0018] Furthermore, in step 4, several falls are required during the drainage process to determine the characteristics of the water inflow-depth drawdown curve and estimate the water inflow.

[0019] Furthermore, in step five, the observation holes need to be arranged vertically to the groundwater flow direction, and the difference in water level drop between adjacent observation holes should not be less than 0.1 m.

[0020] Furthermore, in step five, after the start of self-drainage, observations are made every 5 minutes for the first 30 minutes, and every 30 minutes after 30 minutes. When the water output and water level are close to being stable, observations are made every 1 hour. The water level observation at the observation hole and the water pressure observation at the main hole are carried out simultaneously, and the water level stability standard is that the fluctuation difference does not exceed 2%.

[0021] Furthermore, in step six, the grouting volume is determined by the total grouting pressure, which must be no less than 1.5 times the maximum hydrostatic pressure of the aquifer. The total grouting pressure is composed of the deadweight pressure of the slurry column in the borehole and the pressure of the grouting pump.

[0022] Furthermore, in step seven, the requirements for resuming water level observation are the same as those for water level observation during drainage. If the water level change does not exceed 1 cm per hour for 4 consecutive hours, or the water level rise and fall is consistent with the natural water level change, the observation can be stopped.

[0023] The beneficial effects of the basic scheme are: 1. Compared with the existing technology, this method performs drainage and water plugging reinforcement in the same borehole at the same time, which significantly improves the grouting transformation effect, prevents the grouting material from being washed away by excessive water pressure when the water-bearing stratum is too rich in water, first weakens the water-bearing stratum and then cuts off the recharge water supply path, and prevents secondary water inrush from occurring at the water inrush point during mining.

[0024] 2. Use ground transient electromagnetic exploration technology to pre-divide the working surface, and then conduct drilling to verify it to ensure the accuracy of the judgment of water-rich areas. Perform water quality analysis on aquifer water samples to find out whether there is Ordovician gray water involved in the aquifer, predict the drainage volume, and further prepare for drainage work.

[0025] 3. By arranging observation holes, the water level and water pressure of the aquifer can be timely monitored to provide support for adjusting the amount of water released and to determine the timing of grouting reinforcement. By retaining the observation holes, the dynamic observation network of groundwater in the mine can be improved, the subsequent water pressure can be monitored, and it can be determined whether the pressure is periodic. The subsequent observation holes can also serve as drainage holes, increasing the drainage capacity of the mine. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a schematic diagram of a method for preventing and controlling water inrush from a bottom plate according to an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The following is further described in detail through specific implementation methods:

[0028] The embodiment is basically as shown in the attached Figure 1 A method for preventing and controlling water inrush from a bottom plate comprises the following steps:

[0029] Step 1: Analyze mine conditions: Understand the geological conditions of the aquiclude and aquifer at the mine working face, analyze water filling factors, and clarify groundwater conditions;

[0030] The geological conditions of the aquifer and aquifer include the lithology and effective thickness of the aquifer and the lithology of the aquifer; the water filling factors include atmospheric precipitation, surface water and groundwater; the groundwater conditions include the source of groundwater recharge, runoff pathways and discharge pathways.

[0031] Step 2: Regional evaluation: along the working face, explore the water-richness of the aquifer, identify the hidden faults and water-conducting channels of the floor, and conduct a regional evaluation of the danger of water inrush from the floor, dividing it into abnormal areas and dangerous areas;

[0032] When exploring aquifers, ground transient electromagnetic exploration technology is used. The test line is selected according to the groundwater conditions, and the resistivity cross-section diagram of the test line is obtained. The resistivity is inversely proportional to the water richness.

[0033] Step 3: Drilling: Drill holes to the aquifer in the dangerous and abnormal areas, verify the rationality of the regional division, observe the water gushing from the boreholes, analyze the water quality of the borehole water samples, compare the water quality analysis data to determine the water quality type, and measure the water pressure;

[0034] Borehole water quality analysis includes calcium ion content, pH value, bicarbonate ion content, sulfate ion content, hardness and suspended matter.

[0035] Step 4: Drainage and pressure reduction: Based on step 3, calculate the water inrush coefficient of abnormal and dangerous areas. If the water inrush coefficient is less than 0.06MPa / m, keep the borehole as an observation hole. If the water inrush coefficient is greater than 0.06MPa / m, widen the borehole as the main hole, lower the first casing into the main hole, install a water pump to drain and reduce pressure, and monitor the fluctuations of water pressure and pumping volume throughout the drainage process.

[0036] The water inrush coefficient is the ratio of the hydrostatic pressure in the aquifer to the thickness of the impermeable layer. During the drainage process, several drop strokes are required to determine the characteristics of the water inrush-depth drawdown curve and estimate the water inrush.

[0037] Step 5: Arrange observation holes and monitor: add several observation holes on one side of the main hole to monitor water level changes;

[0038] The observation holes must be arranged vertically to the groundwater flow direction, and the difference in water level drop between adjacent observation holes must not be less than 0.1m. After the start of self-drainage, observations should be made every 5 minutes in the first 30 minutes, and every 30 minutes after 30 minutes. When the water output and water level are close to stability, observations should be made every 1 hour. The water level observation of the observation holes and the water pressure observation of the main hole should be carried out simultaneously. The water level stability standard is that the fluctuation difference does not exceed 2%.

[0039] Step 6: Grouting reinforcement: On the basis of step 4, after the water pressure drops and the water level fluctuation amplitude stabilizes, lower the second casing into the main hole, implement high-pressure grouting reinforcement, and gradually reduce the pumping power of the water pump. After the grouting is completed, stop draining, seal the main hole, and retain the observation hole;

[0040] The grouting volume is determined by the total grouting pressure, which must be no less than 1.5 times the maximum hydrostatic pressure of the aquifer. The total grouting pressure is composed of the deadweight pressure of the slurry column in the main hole and the pressure of the grouting pump.

[0041] Step 7: Verification of reinforcement results: After the grouting reinforcement is completed, observe the restored water level of the observation hole, the dryness of the floor when mining to the abnormal and dangerous areas of the floor, and evaluate the reinforcement effect;

[0042] The requirements for resuming water level observation are the same as those for water level observation during drainage. If the water level change does not exceed 1 cm per hour for 4 consecutive hours, or the water level rise and fall is consistent with the natural water level change, the observation can be stopped.

[0043] The specific implementation process is as follows:

[0044] Step 1: Analyze mine conditions:

[0045] Combined with the hydrogeological map of the mine and the information from the hydrological monitoring station, the lithology of the aquiclude and the aquifer is fully clarified, and data is searched to understand the water storage performance of different lithologies. The aquiclude is divided into a pressurized water conduction zone, a complete rock formation zone and a water conduction damage zone according to the differences in lithology and water storage performance. The thickness of the complete rock formation zone is the effective thickness of the aquiclude. If the effective thickness of the aquiclude is greater than 6m, the protective layer is considered effective. At the same time, the water filling factor is analyzed to determine the groundwater conditions. If the water filling factor is surface water, it is necessary to consider the situation where ground cracks caused by mining and the infiltration of surface water cause the water richness of the aquifer to increase.

[0046] Step 2: Regional evaluation:

[0047] Along the direction of the working face, according to the groundwater conditions, the water-richness of the aquifer is explored using ground transient electromagnetic exploration technology. At least three detection lines are arranged to form three advance detection profiles. When selecting the detection lines, the influence of metal support and water accumulation in the tunnel should be avoided as much as possible. The resistivity cross-section diagram is obtained through the detection profile. The water-richness of the aquifer, the hidden faults in the bottom plate and the water conducting channels are judged by the resistivity, and the abnormal area and the dangerous area are divided.

[0048] Step 3: Drilling:

[0049] Drill holes in abnormal areas and dangerous areas respectively, with a hole diameter of no less than 90mm and a hole depth of at least reaching the water-conducting damage zone. Take water samples from the boreholes for water quality analysis and comparison to consider whether there is Ordovician ash water involved. If there is Ordovician ash water, the amount of water gushing out will be large and the drainage time will need to be extended.

[0050] Step 4: Drain water and reduce pressure:

[0051] The water inrush coefficients of the abnormal area and the dangerous area are calculated respectively by the ratio of the hydrostatic pressure of the aquifer and the effective thickness of the impermeable layer. If the water inrush coefficient is less than 0.06MPa / m, the borehole is retained as an observation hole. If the water inrush coefficient is greater than 0.06MPa / m, the borehole is widened to 500mm-550mm as the main hole, the wall protection pipe and the first casing are lowered, and a submersible pump or a vacuum pump is installed to drain water and reduce pressure. During the drainage process, at least three drop strokes are required, that is, different valves are used to change the water inflow to obtain the depth drop under different flow rates, so as to determine the water inflow-depth drop curve characteristics, calculate the total water inflow and monitor the water pressure at the same time.

[0052] Step 5: Arrange observation holes and monitor:

[0053] An observation hole is added on one side of the main hole. The number of observation holes increases with the depth of the drilling hole. There should be at least two observation holes, and the opening diameter should also be no less than 90mm. The water level observation of the observation hole is carried out simultaneously with the water pressure observation of the main hole to determine the drainage progress.

[0054] Step 6: Grouting reinforcement:

[0055] After the water pressure drops and the water level fluctuation amplitude stabilizes, the second casing is lowered into the main hole. First, bone materials such as sand or gravel are poured to quickly fill the water channel, and then cement-water glass slurry is poured, and then chemical slurry is used to further seal it. During the grouting process, the pumping power of the water pump is gradually lowered. The grouting volume is determined by the total grouting pressure, which depends on the deadweight pressure of the slurry column in the main hole and the pressure of the grouting pump. When the total grouting pressure is greater than or equal to 1.5 times the maximum hydrostatic pressure of the aquifer, the grouting and drainage can be stopped, and the hole can be sealed with mortar sealing method to retain the observation hole.

[0056] Step 7: Verify reinforcement results:

[0057] Continue to observe the water level recovery in the observation hole. If the water level change does not exceed 1 cm per hour for 4 consecutive hours, or the water level rise and fall is consistent with the natural water level change, and the bottom plate of the abnormal area and the dangerous area remains dry, the reinforcement is in good condition and mining work can continue.

[0058] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0059] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for preventing water inrush from a base plate, characterized in that: The following steps are involved: Step 1: Analyze mine conditions: Understand the geological conditions of the aquiclude and aquifer at the mine working face, analyze water filling factors, and clarify groundwater conditions; Step 2: Regional evaluation: along the working face, explore the water-richness of the aquifer, identify the hidden faults and water-conducting channels of the floor, and conduct a regional evaluation of the danger of water inrush from the floor, dividing it into abnormal areas and dangerous areas; Step 3: Drilling: Drill holes to the aquifer in the dangerous and abnormal areas, verify the rationality of the regional division, observe the water gushing from the boreholes, analyze the water quality of the borehole water samples, compare the water quality analysis data to determine the water quality type, and measure the water pressure; Step 4: Drainage and pressure reduction: Based on step 3, calculate the water inrush coefficient of abnormal and dangerous areas. If the water inrush coefficient is less than 0.06MPa / m, keep the borehole as an observation hole. If the water inrush coefficient is greater than 0.06MPa / m, widen the borehole as the main hole, lower the first casing into the main hole, install a water pump to drain and reduce pressure, and monitor the fluctuations of water pressure and pumping volume throughout the drainage process. Step 5: Arrange observation holes and monitor: add several observation holes on one side of the main hole to monitor water level changes; Step 6: Grouting reinforcement: On the basis of step 4, after the water pressure drops and the water level fluctuation amplitude stabilizes, lower the second casing into the main hole, implement high-pressure grouting reinforcement, and gradually reduce the pumping power of the water pump. After the grouting is completed, stop draining, seal the main hole, and retain the observation hole; Step seven, verification of reinforcement results: After the grouting reinforcement is completed, observe the restored water level in the observation hole, and the dryness of the bottom plate during subsequent mining to abnormal and dangerous areas of the bottom plate to evaluate the reinforcement effect.

2. A method for preventing and controlling water inrush from a bottom plate according to claim 1, characterized in that: In step one, the geological conditions of the aquiclude and aquifer include the lithology and effective thickness of the aquiclude and the lithology of the aquifer, the water filling factors include atmospheric precipitation, surface water and groundwater, and the groundwater conditions include the source of groundwater recharge, runoff pathways and discharge pathways.

3. A method for preventing and controlling water inrush from a bottom plate according to claim 2, characterized in that: In step 2, the ground transient electromagnetic exploration technology is used to explore the aquifer, and the test line is selected according to the groundwater conditions to obtain the resistivity cross-section diagram of the test line. The resistivity is inversely proportional to the water richness.

4. A method for preventing and controlling water inrush from a bottom plate according to claim 3, characterized in that: In step three, borehole water quality analysis includes calcium ion content, pH value, bicarbonate ion content, sulfate ion content, hardness and suspended matter.

5. A method for preventing and controlling water inrush from a bottom plate according to claim 4, characterized in that: In step 4, the water inrush coefficient is the ratio of the hydrostatic pressure in the aquifer to the thickness of the aquiclude.

6. A method for preventing and controlling water inrush from a bottom plate according to claim 5, characterized in that: In step 4, several falls are required during the drainage process to determine the characteristics of the water inflow-depth drawdown curve and estimate the water inflow.

7. A method for preventing and controlling water inrush from a bottom plate according to claim 6, characterized in that: In step five, the observation holes need to be arranged vertically to the groundwater flow direction, and the difference in water level drop between adjacent observation holes should not be less than 0.1m.

8. A method for preventing and controlling water inrush from a bottom plate according to claim 7, characterized in that: In step five, after the start of self-drainage, observations are made every 5 minutes for the first 30 minutes, and every 30 minutes after 30 minutes. When the water output and water level are close to being stable, observations are made every 1 hour. The water level observation at the observation hole and the water pressure observation at the main hole are carried out simultaneously. The water level stability standard is that the fluctuation difference does not exceed 2%.

9. A method for preventing and controlling water inrush from a bottom plate according to claim 8, characterized in that: In step six, the grouting volume is determined by the total grouting pressure, which must be no less than 1.5 times the maximum hydrostatic pressure of the aquifer. The total grouting pressure is composed of the deadweight pressure of the slurry column in the main hole and the pressure of the grouting pump.

10. A method for preventing and controlling water inrush from a bottom plate according to claim 9, characterized in that: In step seven, the requirements for resuming water level observation are the same as those for water level observation during drainage. If the water level change does not exceed 1 cm per hour for 4 consecutive hours, or the water level rise and fall is consistent with the natural water level change, the observation can be stopped.

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