Multi-disaster cooperative control method for underground coal mine gangue in-situ pumping column-forming filling mining

Abstract

The invention provides a multi-disaster cooperative control method for coal mine underground gangue in-situ pumping column-forming filling mining. The multi-disaster cooperative control method comprises the steps that S1, coal and gangue are separated, and gangue powder particles are obtained; step S2, preparation of gangue filling slurry; s3, the filling strength q required by a goaf top plate and the supporting strength q filling of a pumping supporting column are calculated, and the constraint condition q filling is larger than q is met; s4, the advancing length of the working face needing to be filled and supported by the pumping supporting columns is equal to the length of the working face, that is, a square is formed in the goaf, and the row distance A between the pumping supporting columns is calculated according to the filling strength q needed by the goaf top plate and the supporting strength q of the pumping supporting columns obtained in the step S3; and S5, construction of the pumping support columns: placing composite-structure double-layer flexible mold bags at intervals in the goaf according to the row distance A between the pumping support columns obtained in the step S4, and injecting the gangue filling slurry obtained in the step S2 into the composite-structure double-layer flexible mold bags through a high-pressure pump to form the pumping support columns in matrix arrangement. According to the method, coal-pillar-free mining can be effectively achieved, the resource recovery efficiency is greatly improved, and various direct or indirect disasters caused by migration of overlying strata in the goaf can be restrained.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mine goaf management, relates to coal mine filling mining, and specifically relates to a multi-hazard coordinated control method for underground coal mine gangue in-situ pumping column filling mining. Background Art

[0002] Coal mining backfilling refers to filling the goaf with materials such as gangue, sand, and gravel underground or on the ground to control rock movement and surface subsidence. According to the filling method, it can be divided into hydraulic filling, wind filling, mechanical filling, and gangue self-flowing filling. Concrete filling has also been used in foreign countries to solve the problem of mining under important buildings.

[0003] With the development of the mining industry, the original filling process can no longer meet the requirements of the recovery process and the need to further reduce mining costs or environmental protection. Therefore, new technologies such as high-concentration filling technology, paste filling, block mortar cementing filling and full tailings cementing filling have been developed. High-concentration filling refers to a filling method in which, after the filling material arrives at the mining site, although there is excess water seeping out, the penetration rate of the excess water is very low and the concentration changes slowly. The materials used to make high-concentration materials include natural aggregates, crushed rock materials and mineral processing tailings. The concept of high concentration of natural sand and tailings generally refers to a filling slurry with a weight concentration of 75%. The so-called paste filling refers to a filling material that is in a paste state and does not dehydrate in the mining site, and its cemented filling body has good strength characteristics. Block mortar cementing filling refers to a high-quality filling technology that uses block stones as filling aggregates and cement slurry or mortar as a cementing medium and does not dehydrate in the mining site. Full tailings cementation filling means that the tailings are not classified and are all used as mine filling materials. This is very valuable for mines with low tailings yields and the need to achieve zero emission goals.

[0004] Although the above filling technologies have achieved good results, they still have many shortcomings, such as high filling costs, poor filling and top connection effects, and overly complicated filling procedures. The above constraints make it difficult to adapt to the current goal of safe and efficient mining, so it is urgent to develop a new filling technology to meet the actual production needs. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for coordinated control of multiple disasters in underground coal mine gangue in-situ pumping column filling mining, so as to solve the technical problem that the multi-effect synergy of the filling method in the prior art needs to be further improved.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems:

[0007] A method for coordinated control of multiple disasters in underground coal mine gangue in-situ pumping column filling mining, the method comprising the following steps:

[0008] Step S1, separation of coal and gangue to obtain gangue powder particles:

[0009] Step S2, preparation of gangue filling slurry:

[0010] Sulphoaluminate cement, water and the gangue powder obtained in step S1 are mixed and stirred to form gangue filling slurry.

[0011] Step S3, calculate the required filling strength q of the goaf roof and the support strength q of the pumping support 充填 , satisfying the constraint q 充填 >q.

[0012] Step S4: The required pumping support support working face advancement length is equal to the working face length, that is, the goaf forms a square. According to the required filling strength q of the goaf roof obtained in step S3 and the support strength q of the pumping support, 充填 Calculate the spacing A between pumping struts.

[0013] The calculation formula for the spacing A between the pumping struts is:

[0014]

[0015] q×L 2 ×f=q 充填 ×πr 2 ×N;

[0016] Where:

[0017] A represents the center-to-center spacing of the pumping struts, and A is rounded to an integer in m.

[0018] L represents the length of the working surface, in m;

[0019] N represents the number of pumping pillars required in the goaf;

[0020] q represents the required filling strength of the goaf roof, in MPa;

[0021] L 2 Indicates the area of ​​the goaf, in m 2 ;

[0022] f represents the safety factor;

[0023] q 充填 Indicates the support strength of the pumping support in MPa;

[0024] r is the cross-sectional radius of the pumping strut, in m.

[0025] Step S5, constructing pumping support:

[0026] In the goaf, double-layer flexible mold bags with composite structures are placed at intervals A between the pumping pillars obtained in step S4, and the gangue filling slurry obtained in step S2 is injected into each double-layer flexible mold bag with composite structures by a high-pressure pump to form pumping pillars arranged in a matrix.

[0027] Compared with the prior art, the present invention has the following technical effects:

[0028] (I) The method of the present invention screens and processes gangue in situ, and adopts a pumping column method to fill the goaf, which effectively avoids the problems existing in the traditional filling method, can effectively realize coal pillar-free mining, greatly improve resource recovery efficiency, and can inhibit various direct or indirect disasters caused by the migration of overburden in the goaf, including but not limited to roof water damage, strong mine pressure disasters and house damage caused by surface subsidence, providing technical equipment support for green, efficient and safe mining of coal mines.

[0029] (II) The method of the present invention adopts a pumping column filling method to form a permanent support for the goaf, which can suppress the safety accidents and economic losses caused by the fracture, concentrated collapse and large-scale collapse of the roof of the goaf.

[0030] (III) The method of the present invention uses pumping pillar technology to conduct in-depth research on the development height of the "three zones" and the stress distribution law of the mining area, which helps to reveal the coordinated control mechanism of multiple disasters in the roof filling by pumping waste rock into pillars.

[0031] (IV) The surface subsidence data collected by the method of the present invention within the filling area is significantly lower than the subsidence data of natural collapse or forced collapse, which is beneficial to reducing the impact of coal mining on the surface environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a front view structural schematic diagram of the composite structure double-layer flexible mold bag in the present invention.

[0033] Figure 2 yes Figure 1 Schematic diagram of the cross-sectional structure of the composite structure double-layer flexible mold bag.

[0034] The meanings of the numbers in the figure are: 100 - composite structure double-layer flexible mold bag, 110 - inner nylon fiber membrane bag, 120 - pressure-bearing frame, 130 - outer nylon fiber membrane bag.

[0035] The specific contents of the present invention are further explained in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0036] It should be noted that, unless otherwise specified, all materials and equipment in the present invention are materials and equipment known in the prior art.

[0037] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0038] Example:

[0039] This embodiment provides a method for coordinated control of multiple disasters in underground coal mine waste rock in-situ pumping column filling mining, the method comprising the following steps:

[0040] Step S1, separation of coal and gangue to obtain gangue powder particles:

[0041] The specific process of step S1 is: the raw coal mined from the coal mining face or the tunneling face is transported to the raw coal bunker in the mining area through the coal mining belt for temporary storage, and then part of the raw coal in the raw coal bunker is transported to the chamber near the mining area through the raw coal transfer belt for crushing and sorting of coal and gangue, the sorted coal body is transported to the clean coal bunker through the coal transport belt, and the sorted gangue is transported to the gangue crusher through the gangue transport belt, and is crushed at least once to form gangue powder.

[0042] In step S1, during the crushing and sorting of coal and gangue, the coal and gangue need to be crushed to a particle size of less than 50 mm first, and then sorted using a jig.

[0043] In step S1, the chamber near the mining area refers to a dedicated horizontal tunnel opened in the coal mining working face or a chamber of a certain size.

[0044] In step S1, the particle size of the gangue powder is less than 10 mm.

[0045] Step S2, preparation of gangue filling slurry:

[0046] Sulphoaluminate cement, water and the gangue powder obtained in step S1 are mixed and stirred to form gangue filling slurry.

[0047] In step S2, the mass ratio of sulphoaluminate cement, water and gangue powder is 1:3:3.

[0048] In step S2, the main performance indicators of the gangue filling slurry are as follows:

[0049] The setting time is 3 to 7 minutes.

[0050] The wet specific gravity of the slurry is 1300g / m 3 Up to 1450kg / m 3 .

[0051] Table 1 Pressure test results of gangue filling slurry

[0052] Strength development time 2h 4h 1d 3d 7d 14d 20d Compressive strength / MPa ≥1 ≥2 ≥3 ≥4 ≥6 ≥8 ≥10

[0053] Step S3, calculate the required filling strength q of the goaf roof and the support strength q of the pumping support 充填 , satisfying the constraint q 充填 >q.

[0054] In step S3, the calculation formula for the filling strength q required for the goaf roof is:

[0055] q=KHγg×10 -6 ;

[0056] Where:

[0057] q represents the required filling strength of the goaf roof, in MPa;

[0058] K represents the ratio of the thickness of the overlying rock layer supported by the support of the coal mining face to the mining height. Preferably, K is 4

[0059] to 8;

[0060] H represents the mining height, in meters;

[0061] γ represents the density of roof rock, in kg / m 3 ;

[0062] g represents the acceleration due to gravity, in m / s 2 .

[0063] 5. The method for multi-hazard coordinated control of underground gangue in-situ pumping column filling mining according to claim 1, characterized in that in step S3, the support strength q of the pumping support column is 充填 The calculation formula is:

[0064] q 充填 =P / R×10 -3 =P / 2BN×10 -3 ;

[0065] Where:

[0066] q 充填 Indicates the support strength of the pumping support in MPa;

[0067] P represents the support resistance of the working surface, in kN;

[0068] R represents the support area of ​​the bracket, in m 2 ;

[0069] B represents the center distance of a single set of brackets, in meters;

[0070] N represents the length of the bracket top beam, in meters.

[0071] Step S4: The required pumping support support working face advancement length is equal to the working face length, that is, the goaf forms a square. According to the required filling strength q of the goaf roof obtained in step S3 and the support strength q of the pumping support, 充填 Calculate the spacing A between pumping struts.

[0072] The calculation formula for the spacing A between pumping struts is:

[0073]

[0074] q×L 2 ×f=q 充填 ×πr 2 ×N;

[0075] Where:

[0076] A represents the center-to-center spacing of the pumping struts, and A is rounded to the nearest integer in m.

[0077] L represents the length of the working surface, in m;

[0078] N represents the number of pumping pillars required in the goaf;

[0079] q represents the required filling strength of the goaf roof, in MPa;

[0080] L 2 Indicates the area of ​​the goaf, in m 2 ;

[0081] f represents the safety factor, preferably, f is 1.1 to 1.2;

[0082] q 充填 Indicates the support strength of the pumping support in MPa;

[0083] r is the cross-sectional radius of the pumping strut, in m.

[0084] Step S5, constructing pumping support:

[0085] In the goaf, double-layered flexible mold bags 100 of composite structures are placed at intervals A between the pumping pillars obtained in step S4, and the gangue filling slurry obtained in step S2 is injected into each double-layered flexible mold bag 100 of composite structures by a high-pressure pump to form pumping pillars arranged in a matrix.

[0086] In step S5, the construction sequence of the pumping pillars is: advance simultaneously in the manner of front mining and rear filling, and the length of the filling area along the mining direction is controlled to be greater than the row spacing A between one pumping pillar and less than the row spacing A between two pumping pillars. That is, coal mining and pumping pillar filling of the goaf generated by coal mining are carried out simultaneously.

[0087] In step S5, Figure 1 and Figure 2 As shown, the composite structure double-layer flexible mold bag 100 includes an inner nylon fiber membrane bag 110 with a cylindrical structure, an outer nylon fiber membrane bag 130 with a cylindrical structure coaxially mounted outside the inner nylon fiber membrane bag 110, and a pressure-bearing frame 120 is fixedly mounted between the outer annular wall of the inner nylon fiber membrane bag 110 and the inner annular wall of the outer nylon fiber membrane bag 130.

[0088] In this embodiment, the composite structure double-layer flexible mold bag 100 has the characteristics of high strength, flame retardancy, antistatic and side limit pressurization, and can be quickly molded by one-time injection molding. The inner nylon fiber membrane bag 110 and the outer nylon fiber membrane bag 130 wrap the filling slurry to adaptively maintain pressure, and the pressure-bearing skeleton 120 self-bearing side limit pressure is applied. Compared with other metal material templates, the weight is reduced by 62%, and the composite structure double-layer flexible mold bag 100 has an ability to resist lateral pressure that is 29% higher than that of a single mold bag. The pumped filling slurry is limited by the composite structure double-layer flexible mold bag 100, which effectively controls the lateral deformation. The later strength of the gangue filling slurry combination can be increased by more than 34% compared with the strength of the traditional pillar, and rapid molding can be achieved to meet the filling requirements of the goaf under high mining intensity. The displacement sensor 140 can record the filling height and height change data of the composite structure double-layer flexible mold bag 100 in real time, providing data support for the later material ratio optimization.

[0089] In step S5, further, a displacement sensor is built into the top of the composite structure double-layer flexible mold bag 100 to monitor the displacement of all pumping pillars in the goaf, and upload the data to the ground in real time through a communication cable. By collecting the data of the displacement sensor, the displacement data is matched with different material ratios, and the material ratio is continuously optimized according to the actual situation on site.

Claims

1. A method for coordinated control of multiple disasters in underground coal mine waste rock in-situ pumping column filling mining, characterized in that: The method comprises the following steps: Step S1, separation of coal and gangue to obtain gangue powder particles: Step S2, preparation of gangue filling slurry: Mixing and stirring sulphoaluminate cement, water and the gangue powder obtained in step S1 to form gangue filling slurry; Step S3, calculate the required filling strength q of the goaf roof and the support strength q of the pumping support 充填 , satisfying the constraint q 充填 >q; Step S4: The required pumping support support working face advancement length is equal to the working face length, that is, the goaf forms a square. According to the required filling strength q of the goaf roof obtained in step S3 and the support strength q of the pumping support, 充填 Calculate the spacing A between pumping struts; The calculation formula for the spacing A between the pumping struts is: q×L 2 ×f=q 充填 ×πr 2 ×N; Where: A represents the center-to-center spacing of the pumping struts, and A is rounded to an integer in m. L represents the length of the working surface, in m; N represents the number of pumping pillars required in the goaf; q represents the required filling strength of the goaf roof, in MPa; L 2 Indicates the area of ​​the goaf, in m 2 ; f represents the safety factor; q 充填 Indicates the support strength of the pumping support in MPa; r is the cross-sectional radius of the pumping strut, in m; Step S5, constructing pumping support: In the goaf, double-layered flexible mold bags (100) of composite structures are placed at intervals according to the spacing A between the pumping pillars obtained in step S4, and the gangue filling slurry obtained in step S2 is injected into each double-layered flexible mold bag (100) of composite structures by a high-pressure pump to form pumping pillars arranged in a matrix.

2. The method for coordinated control of multiple disasters in underground coal mine gangue in-situ pumping column filling mining as claimed in claim 1, characterized in that: In step S2, the mass ratio of the sulphoaluminate cement, water and gangue powder is 1:3:

3.

3. The multi-hazard coordinated control method for in-situ pumping and column filling mining of coal mine gangue as claimed in claim 1, characterized in that: In step S5, the composite structure double-layer flexible mold bag (100) includes an inner nylon fiber membrane bag (110) with a cylindrical structure, an outer nylon fiber membrane bag (130) with a cylindrical structure coaxially mounted outside the inner nylon fiber membrane bag (110), and a pressure-bearing frame (120) is fixedly mounted between the outer annular wall of the inner nylon fiber membrane bag (110) and the inner annular wall of the outer nylon fiber membrane bag (130).

4. The method for coordinated control of multiple disasters in underground coal mine gangue in-situ pumping column filling mining as claimed in claim 1, characterized in that: In step S3, the calculation formula for the filling strength q required for the goaf roof is: q=KHγg×10 -6 ; Where: q represents the required filling strength of the goaf roof, in MPa; K represents the ratio of the thickness of the overlying rock strata supported by the support of the coal mining face to the mining height; H represents the mining height, in meters; γ represents the density of roof rock, in kg / m 3 ; g represents the acceleration due to gravity, in m / s 2 .

5. The method for coordinated control of multiple disasters in underground coal mine gangue in-situ pumping column filling mining as claimed in claim 1, characterized in that: In step S3, the support strength q of the pumping support 充填 The calculation formula is: q 充填 =P / R×10 -3 =P / 2BN×10 -3 ; Where: q 充填 Indicates the support strength of the pumping support in MPa; P represents the support resistance of the working surface, in kN; R represents the support area of ​​the bracket, in m 2 ; B represents the center distance of a single set of brackets, in meters; N represents the length of the bracket top beam, in meters.

6. The method for coordinated control of multiple disasters in underground coal mine gangue in-situ pumping column filling mining as claimed in claim 1, characterized in that: The specific process of step S1 is: the raw coal mined from the coal mining face or the tunneling face is transported to the raw coal bunker in the mining area through the coal mining belt for temporary storage, and then part of the raw coal in the raw coal bunker is transported to the chamber near the mining area through the raw coal transfer belt for crushing and sorting of coal and gangue, the sorted coal body is transported to the clean coal bunker through the coal transport belt, and the sorted gangue is transported to the gangue crusher through the gangue transport belt, and is crushed at least once to form gangue powder.

7. The method for coordinated control of multiple disasters in underground coal mine gangue in-situ pumping column filling mining as claimed in claim 6, characterized in that: In step S1, the particle size of the gangue powder is less than 10 mm.

8. The method for coordinated control of multiple disasters in underground coal mine gangue in-situ pumping column filling mining as claimed in claim 1, characterized in that: In step S5, the construction sequence of the pumping pillars is: advance simultaneously in the manner of front mining and rear filling, and the length of the filling area along the mining direction is controlled to be greater than the row spacing A between one pumping pillar and less than the row spacing A between two pumping pillars.

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