Rock burst, gas outburst and dust composite disaster integrated prevention and control method

Abstract

The invention relates to the technical field of coal rock dynamic disaster prevention and control, in particular to a rock burst, gas outburst and dust composite disaster integrated prevention and control method which mainly comprises the steps that firstly, a plurality of pressure relief holes are drilled in a coal body in a transportation crossheading and an air return crossheading, gas extraction is carried out on the pressure relief holes, then secondary drilling is carried out on the pressure relief holes, and the gas outburst and dust composite disaster integrated prevention and control method is obtained. And deep gas extraction holes and deep coal seam water injection holes are formed, then gas extraction of the deep gas extraction holes and water injection of the deep coal seam water injection holes are conducted at the same time, and finally grouting plugging is conducted. According to the method, preliminary pressure relief is conducted on the coal body, gas accumulation of coal rock mass at the shallow portion of the roadway is reduced, then deep gas extraction and water injection are conducted at the same time, and deep gas extraction and deep coal seam water injection of the coal face can intersect and cooperate with each other in the coal body; the effects of extracting gas from a deep coal seam, wetting and softening the coal body and improving the physical and mechanical properties of the coal and rock mass are more effectively achieved, and pressure relief-extraction-water injection integrated prevention and control are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of coal-rock dynamic disaster prevention and control, and in particular to an integrated prevention and control method for rock burst, gas outburst and dust composite disasters. Background Art

[0002] With the continuous expansion of mining depth and scale, the geological conditions of mines have become more complicated, resulting in a significant increase in disaster risks. In deep mining areas, coal-rock composite dynamic disasters have occurred, where coal and gas outbursts interact with rock bursts. In some mines, the gas level has changed from low to high, and the mines have changed from non-outburst mines to outburst mines. The permeability of coal seams has decreased, gas extraction has become difficult, the gas outburst volume at the working face has exceeded the limit, and gas outbursts and explosion accidents have occurred frequently, which has had a serious impact on the safety and efficient production of coal mines. In addition, the dust generated during coal mining damages mine equipment, shortens equipment life, and poses a serious threat to the health of miners, especially the risk of pneumoconiosis. Excessive high dust concentrations also increase the possibility of dust explosions. Once a dust explosion occurs, it will result in significant casualties and property losses.

[0003] For coal seams with coal and gas outbursts, anti-outburst measures are generally taken, which may increase the impact tendency of the coal body and thus cause rock burst disasters. For coal seams susceptible to rock burst, methods such as drilling pressure relief are usually used for prevention and control, which may induce coal and gas outbursts. In view of the high dust concentration and explosion risk underground, the main dust prevention measure is spray dust reduction technology. However, since the fine water outlet holes of high-pressure nozzles are easily blocked by coal mud and rock particles, and may be restricted by factors such as water shortage during excavation operations, the effect of relying solely on spray dust reduction is often unsatisfactory. The existing control technologies and concepts for rock burst, coal and gas outbursts, and underground dust concentration are no longer sufficient to meet the prevention and control needs of coal-rock composite dynamic disasters. Therefore, it is urgent to develop a comprehensive composite disaster control method to achieve the prevention and control of coal and gas outbursts, the reduction of rock bursts, and the reduction of underground dust concentration, so as to achieve the coordinated control of composite disasters. Summary of the invention

[0004] Based on the above problems, the purpose of the present invention is to provide a prevention and control method that can synergistically solve the combined disasters of coal seam impact ground pressure, gas outburst and dust, so as to achieve the best prevention and control effect of integrated prevention of impact, leakage and water injection and dust reduction.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] An integrated prevention and control method for rock burst, gas outburst and dust composite disasters comprises the following steps:

[0007] Step 1: Drill multiple pressure relief holes in the coal body in the transport chute and the return air chute, and extract gas from the pressure relief holes;

[0008] Step 2: Drilling multiple pressure relief holes for the second time to form deep gas extraction holes and deep coal seam water injection holes;

[0009] Step 3: Simultaneously perform gas extraction from deep gas extraction holes and water injection into deep coal seam water injection holes;

[0010] Step 4: Grouting and plugging of deep gas extraction holes and deep coal seam water injection holes;

[0011] Furthermore, in the step 1, a plurality of pressure relief holes are vertically drilled into the coal body in the transport chute and the return air chute located between the coal seam roof and the coal seam floor, and the plurality of pressure relief holes are arranged in layers and staggered in the transport chute and the return air chute;

[0012] Furthermore, in the step 2, when the pressure relief hole after gas extraction is drilled for the second time, the gas extraction hole and the deep coal seam water injection hole are determined based on the gas concentration and the development of fractures in the borehole;

[0013] Furthermore, in step 3, when water is injected into the deep coal seam water injection hole, a composite wetting agent with a concentration of 1.5% is added to the water, wherein the composite wetting agent is composed of a chelating agent sodium gluconate, a surfactant fatty alcohol polyoxyethylene ether and a fatty alcohol polyoxyethylene ether sodium sulfate, and the preparation ratio is 1:1:1, and the single mass concentration is 0.5%;

[0014] Furthermore, before the grouting and plugging in step 4, the deep gas extraction hole and the deep coal seam water injection hole are cleaned, and the grouting pipe is inserted into the predetermined depth of the borehole to ensure that the grouting pipe is firmly fixed and will not be withdrawn due to the slurry pressure;

[0015] Furthermore, the grouting material used for grouting and plugging in step 4 is ultrafine cement or modified water glass;

[0016] Furthermore, the grouting method of step four adopts a segmented grouting method, starting from the bottom of the hole and grouting upwards segment by segment.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. The present invention performs preliminary pressure relief on the coal body by drilling pressure relief holes on the transport chute and the return air chute of the coal mining face, which can increase the cracks in the coal body, increase the permeability of the coal seam, improve the effect of subsequent gas extraction, and reduce the gas accumulation in the shallow coal rock mass of the tunnel. Then, on the basis of the pressure relief holes, deep gas extraction holes and deep coal seam water injection holes are further drilled, and deep gas extraction and water injection are performed at the same time, so that the deep gas extraction and deep coal seam water injection of the coal mining face can cross and cooperate with each other in the coal body, which can more effectively extract gas from the deep coal seam, moisten and soften the coal body, improve the physical and mechanical properties of the coal rock mass, reduce the dust generated during the mining process, and curb dust explosion accidents, thereby realizing the integrated prevention and control of "pressure relief-extraction-water injection".

[0019] 2. The present invention can not only remove gas and reduce the gas content of coal body by adding composite wetting agent in coal seam water injection, but also soften coal body and reduce the impact tendency of coal rock body, and can also reduce dust generated in the mining process and improve the working environment of workers. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a flow chart of the present invention;

[0021] Figure 2 It is a plan view of the arrangement of the drilling holes in the example of the present invention (a transverse cross-sectional view along the transport chute and the return air chute);

[0022] Figure 3 For along Figure 2 Vertical section view of the middle return air chute;

[0023] In the figure: 1. Pressure relief hole; 2. Deep gas extraction hole; 3. Deep coal seam water injection hole; 4. Coal body; 5. Transport chute; 6. Return air chute; 7. Coal mining face; 8. Goaf; 9. Coal seam roof; 10. Coal seam floor. DETAILED DESCRIPTION

[0024] The technical solution adopted by the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments of the specification.

[0025] In this embodiment, the average length of the mineable strike of the coal mining face 7 in a certain mining area is 1035.8m, the average burial depth is 900m, the inclined length of the face is 198m, and the average coal thickness is 6m. According to the identification and analysis, the coal mining face 7 in the mining area has a combined coal-rock dynamic disaster of rock burst and gas outburst, and the coal dust flying in the mining process is explosive.

[0026] To eliminate the above risks, Figure 1 As shown, the present invention provides an integrated prevention and control method for rock burst, gas outburst and dust composite disasters, comprising the following steps:

[0027] Step 1: Drill multiple pressure relief holes 1 into the coal body 4 in the transport chute 5 and the return air chute 6, and extract gas from the pressure relief holes 1;

[0028] Specifically, Figure 2 As shown, a plurality of pressure relief holes 1 are vertically drilled into the coal body 4 in the transport chute 5 and the return air chute 6 located between the coal seam roof 9 and the coal seam floor 10. The plurality of pressure relief holes 1 are layered and staggered in the transport chute 5 and the return air chute 6. The layering is to drill a plurality of pressure relief holes 1 of different heights in the upper side of the transport chute 5 and the lower side of the return air chute 6, or to drill the pressure relief holes 1 in the lower side of the transport chute 5 and the upper side of the return air chute 6. The staggering is that the positions of the pressure relief holes 1 in adjacent layers are staggered, that is, the initial pressure relief of the entire coal body 4 is achieved by the plurality of pressure relief holes 1 arranged in a layered and staggered manner, and mutual interference in subsequent steps can also be effectively prevented.

[0029] The diameter, depth and spacing of the pressure relief holes 1 can be determined according to the geological conditions of the coal mining face 7 and the results of the risk assessment of the combined dynamic disasters;

[0030] In this embodiment, Figure 3 As shown, starting from 15m at the coal mining face 7 located between the coal seam roof 9 and the coal seam floor 10 in front of the goaf 8, according to the geological conditions of the mine working face, pressure relief holes 1 with a hole diameter of 115mm, a hole depth of 30m and a mutual spacing of 2.25m are drilled along the coal seam at the lower wall of the transport chute 5 and the upper wall of the return air chute 6 of the coal mining face 7, and are spatially staggered on the transport chute 5 and the return air chute 6; preliminary pressure relief is performed on the coal body 4 through the pressure relief holes 1;

[0031] While drilling the pressure relief hole 1, the pressure relief hole 1 is sealed and gas is extracted in time to prevent gas leakage in the shallow part of the coal body 4;

[0032] In this embodiment, the gas extraction of the pressure relief hole 1 can be carried out using a mining gas extraction device with a sealing function. The pressure relief hole 1 is first sealed with a sealing length of 9m, and then the gas extraction device is connected to the extraction pipeline for gas extraction.

[0033] Step 2: After the gas extraction is completed, the multiple pressure relief holes 1 are drilled again, and the multiple pressure relief holes 1 after the secondary drilling are divided into deep gas extraction holes 2 and deep coal seam water injection holes 3;

[0034] Specifically, when the pressure relief hole 1 is drilled for the second time after gas extraction, the gas concentration is tested, and the development of fractures in the borehole is observed with an endoscope. The hole with high gas concentration and poor fracture development is selected as the deep gas extraction hole 2, and the hole with low gas concentration and good fracture development is selected as the deep coal seam water injection hole 3. If the two are close, the higher one is used as the deep gas extraction hole 2, and the lower one is used as the deep coal seam water injection hole 3 to prevent water from running into the gas extraction hole from top to bottom along the fractures during water injection, affecting its extraction effect.

[0035] In this embodiment, a deep borehole with a diameter of 90 mm is continued to be drilled along the axial direction of the pressure relief hole 1 at the bottom of the pressure relief hole 1 after gas extraction, so that the depth of the entire pressure relief hole 1 after the secondary drilling reaches 110 m, and the bottom end of the pressure relief hole 1 after the secondary drilling should exceed the central axis of the coal mining section by 10 m to avoid the formation of a blank zone for gas extraction or coal seam water injection in the middle of the coal mining face, and according to the gas concentration detection and the development of fractures in the borehole, the lower pressure relief hole 1 after the secondary drilling is used as the deep gas extraction hole 2, and the upper pressure relief hole 1 after the secondary drilling is used as the deep coal seam water injection hole 3.

[0036] Step 3: Simultaneously extracting gas from the deep gas extraction hole 2 and injecting water into the deep coal seam water injection hole 3;

[0037] Specifically, in this embodiment, the corresponding gas extraction device and water injection device are used to simultaneously perform gas extraction and water injection on the deep gas extraction hole 2 and the deep coal seam water injection hole 3;

[0038] Since gas extraction utilizes the cracks in the coal body 4 to extract gas from the deep gas extraction hole 2, and water injection does the opposite by utilizing the cracks. By injecting water into the deep coal seam water injection hole 3, water enters the coal body 4 through the cracks to moisten the coal body 4, thereby achieving the effect of dust reduction during mining. Therefore, through simultaneous gas extraction and water injection, not only can the prevention and control time be reduced and manpower, material and financial resources be saved, but deep gas extraction and water injection can also be cross-coordinated to achieve better protection effects.

[0039] In addition, as a preferred technical solution, in order to further increase the effective wetting range of water in the medium 4 during water injection, a composite wetting agent can be added to the water at a concentration of 1.5%, i.e., 1m 3 15 kg of a composite wetting agent is added to water. The composite wetting agent consists of a chelating agent sodium gluconate (GASS), a surfactant fatty alcohol polyoxyethylene ether (AEO-3) and a fatty alcohol polyoxyethylene ether sodium sulfate (AES). The preparation ratio is 1:1:1, and the single mass concentration is 0.5%.

[0040] Step 4: grouting and plugging the deep gas extraction hole 2 and the deep coal seam water injection hole 3;

[0041] After gas extraction and water injection are completed, the deep gas extraction hole 2 and the deep coal seam water injection hole 3 need to be grout-sealed to prevent gas leakage, coal seam spontaneous combustion, water leakage and improve the bearing capacity of the coal body 4.

[0042] Specifically, before implementing grouting and sealing, the deep gas extraction hole 2 and the deep coal seam water injection hole 3 need to be cleaned to ensure that there are no debris, coal powder, etc. in the hole to ensure the grouting effect; and the grouting pipe is inserted into the predetermined depth of the borehole to ensure that the grouting pipe is firmly fixed and will not be withdrawn due to slurry pressure.

[0043] According to the characteristics of the coal body 4, such as hardness, degree of fissure development, gas content, etc., select appropriate grouting materials. For deep drilling, grouting materials with good permeability and rapid solidification properties are generally used, preferably ultrafine cement or modified water glass, which are mixed according to the designed proportion. Before grouting, debug the grouting pump to ensure that the grouting pump works normally. The grouting pressure should be slightly higher than the maximum bearing pressure of the coal seam, but should not be too high to prevent the coal seam from breaking. At the same time, the grouting volume is calculated according to the volume of the borehole and the expected fissure development. The grouting speed should be adjusted according to the grouting pressure and flow rate to avoid material accumulation caused by too fast.

[0044] The grouting method preferably adopts the segmented grouting method, starting from the bottom of the hole, and grouting upwards step by step, that is, grouting is carried out in order from bottom to top, first grouting deep holes and then shallow holes. Grouting is terminated when the designed grouting pressure is reached and stabilized for a certain period of time and the grouting volume reaches the design requirements or slurry seepage occurs around the borehole.

[0045] In addition, when performing grouting and plugging operations of deep gas extraction holes 2 and deep coal seam water injection holes 3, in order to ensure construction safety and improve the plugging effect, the following precautions must be strictly observed:

[0046] First, ensure the safety and reliability of grouting equipment and pipelines, and set up cordons to prevent unauthorized personnel from entering;

[0047] Secondly, closely monitor gas concentration and take safety measures to prevent gas accumulation and exceeding the limit, especially in gas outburst danger areas; at the same time, accurately control grouting pressure to avoid being too high or too low to protect the coal seam structure and ensure adequate plugging;

[0048] In addition, the grouting materials are mixed strictly according to the material ratio to ensure quality; grouting materials with little impact on the environment are selected to reduce pollution to groundwater and soil;

[0049] Finally, formulate emergency plans to deal with various problems that may arise, such as grouting interruption, equipment failure, etc. Through these comprehensive measures, the smooth progress of grouting and plugging work can be effectively guaranteed.

[0050] The entire prevention and treatment process is completed through the above steps. Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. An integrated prevention and control method for rock burst, gas outburst and dust composite disasters, characterized in that: The following steps are involved: Step 1: Drill multiple pressure relief holes in the coal body in the transport chute and the return air chute, and extract gas from the pressure relief holes; Step 2: Drilling multiple pressure relief holes for the second time to form deep gas extraction holes and deep coal seam water injection holes; Step 3: Simultaneously perform gas extraction from deep gas extraction holes and water injection into deep coal seam water injection holes; Step 4: Grouting and sealing of deep gas extraction holes and deep coal seam water injection holes.

2. The integrated prevention and control method for rock burst, gas outburst and dust composite disasters according to claim 1 is characterized in that: In the step 1, a plurality of pressure relief holes are vertically drilled into the coal body in the transport chute and the return air chute located between the coal seam roof and the coal seam floor, and the plurality of pressure relief holes are arranged in layers and staggered in the transport chute and the return air chute.

3. The integrated prevention and control method for rock burst, gas outburst and dust composite disasters according to claim 1 is characterized in that: The gas extraction holes and deep coal seam water injection holes in step 2 are determined based on the gas concentration in the borehole and the development of fractures in the borehole.

4. The integrated prevention and control method for rock burst, gas outburst and dust composite disasters according to claim 1 is characterized in that: In the step three, when injecting water into the deep coal seam water injection hole, a composite wetting agent with a concentration of 1.5% is added to the water. The composite wetting agent is composed of a chelating agent sodium gluconate, a surfactant fatty alcohol polyoxyethylene ether and a fatty alcohol polyoxyethylene ether sodium sulfate. The preparation ratio is 1:1:1, and the single mass concentration is 0.5%.

5. The integrated prevention and control method for rock burst, gas outburst and dust composite disasters according to claim 1 is characterized in that: Before the grouting and sealing in step 4, the deep gas extraction holes and deep coal seam water injection holes are cleaned, and the grouting pipe is inserted into the predetermined depth of the borehole to ensure that the grouting pipe is firmly fixed and will not be withdrawn due to the slurry pressure.

6. The integrated prevention and control method for rock burst, gas outburst and dust composite disasters according to claim 1 is characterized in that: The grouting material used for grouting and plugging in step 4 is ultra-fine cement or modified water glass.

7. The integrated prevention and control method for rock burst, gas outburst and dust composite disasters according to claim 1 is characterized in that: The grouting method of step 4 adopts the segmented grouting method, starting from the bottom of the hole and grouting upwards segment by segment.

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