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

Abstract

This invention provides a method for coordinated control of multiple hazards in underground coal mine gangue in-situ pumped pillar filling mining, comprising: step S1, separating coal and gangue to obtain gangue powder; step S2, preparing gangue filling slurry; and step S3, calculating the required filling strength q of the goaf roof and the support strength q of the pumped pillar. 充填 Satisfying constraint q 充填 >q; Step S4, the required pumping support for filling the working face advance length is equal to the working face length, that is, the goaf forms a square, based on the required filling strength q of the goaf roof and the support strength q of the pumping support obtained in step S3. 充填 Calculate the spacing A between pumping supports; Step S5, construct the pumping supports: In the goaf, place composite double-layer flexible formwork bags at intervals according to the spacing A obtained in step S4. Inject the gangue filling grout obtained in step S2 into each composite double-layer flexible formwork bag using a high-pressure pump, forming a matrix arrangement of pumping supports. The method of this invention can effectively achieve pillarless mining, greatly improve resource recovery efficiency, and suppress various direct or indirect disasters caused by overburden migration in the goaf.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of coal mine goaf treatment, and relates to coal mine filling mining, in particular to a multi-disaster synergistic control method for coal mine underground gangue in-situ pumping columnar filling mining. BACKGROUND

[0002] Coal mine filling mining refers to filling a goaf with gangue, sand, broken stone and other materials underground or on the ground to achieve the purpose of controlling rock movement and surface subsidence. According to the filling method, it can be divided into hydraulic filling, pneumatic filling, mechanical filling, and gangue self-sloughing filling. Abroad, concrete filling has also been used to solve the problem of mining under important buildings.

[0003] With the development of the mining industry, the original filling process cannot meet the requirements of the stoping process and the needs of further reducing mining costs or environmental protection, so new technologies such as high-concentration filling, paste filling, block stone mortar cementation filling and full tailings cementation filling have been developed. High-concentration filling refers to a filling method in which the filling material reaches the stope with excess water seeping out, but the seepage speed of the excess water is very low and the concentration changes slowly. The high-concentration material is made of natural aggregate, crushed rock and tailings. The concept of high concentration of natural sand and tailings is generally that the weight concentration of the filling slurry reaches 75%. Paste filling refers to a filling material in paste form that does not dehydrate in the stope, and the cemented filling body has good strength characteristics. Block stone mortar cementation filling refers to a high-quality filling technology that uses block stone as filling aggregate and cement mortar or sand mortar as cementing medium without dehydrating in the stope. Full tailings cementation filling refers to the use of tailings without classification for mine filling, which is very valuable for mines with low tailings yield and zero emission targets.

[0004] However, although the above filling technologies have achieved good results, there are still many shortcomings, such as high filling cost, poor filling roof contact effect, and excessive filling process complexity. The above constraints make it difficult to adapt to the current goal of safe and efficient mining, so a new filling technology needs to be developed to meet the actual needs of production. SUMMARY

[0005] In view of the deficiencies in the prior art, the purpose of the present application is to provide a multi-disaster synergistic control method for coal mine underground gangue in-situ pumping columnar filling mining, which solves 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 application adopts the following technical solutions:

[0007] A multi-disaster synergistic control method for coal mine underground gangue in-situ pumping columnar 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] Mix and stir the sulphoaluminate cement, water and the gangue powder particles obtained in step S1 to form the gangue filling slurry.

[0011] Step S3, calculation of the filling strength required for the goaf roof q and the support strength of the pumping prop q 充填 , satisfying the constraint condition .

[0012] Step S4, the working face advancing length supported by the required pumping prop filling is equal to the working face length, i.e. the goaf forms a square, and according to the filling strength required for the goaf roof q and the support strength of the pumping prop q 充填 calculate the pumping prop inter-row spacing A .

[0013] The calculation formula of the pumping prop inter-row spacing A is:

[0014] ;

[0015] ;

[0016] In the formula:

[0017] A represents the center inter-row spacing of the pumping prop, A rounded off, unit: m;

[0018] L represents the working face length, unit: m;

[0019] N represents the number of pumping props required for the goaf;

[0020] q represents the filling strength required for the goaf roof, unit: MPa;

[0021] L 2 represents the goaf area, unit: m 2 ;

[0022] f represents the safety factor;

[0023] q 充填represents the support strength of the pumping pillar, with the unit of MPa;

[0024] r represents the cross-sectional radius of the pumping pillar, with the unit of m.

[0025] Step S5, construction of the pumping pillar:

[0026] The pumping pillars are arranged in the goaf according to the interval distance obtained in step S4 A The composite structure double-layer flexible mold bag is placed at intervals, the gangue filling slurry obtained in step S2 is injected into each composite structure double-layer flexible mold bag through a high-pressure pump, and the matrix-arranged pumping pillars are formed.

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

[0028] (I) The method of the present application performs gangue screening and processing in situ, and adopts the pumping pillar forming mode for goaf filling, effectively avoiding the problems existing in the traditional filling mode, and can effectively realize coal pillarless mining, greatly improve the resource recovery efficiency, and can inhibit various direct or indirect disasters caused by the migration of overburden rock in the goaf, including but not limited to roof water damage, strong mine pressure disaster, and house damage caused by surface subsidence, thereby providing technical equipment support for green, efficient and safe mining of coal mines.

[0029] (II) The method of the present application adopts the pumping pillar forming filling mode to form a permanent support in the goaf, which can inhibit safety accidents and economic losses caused by roof fracture, concentrated collapse and large-area collapse in the goaf.

[0030] (III) The method of the present application uses the pumping pillar technology, and deeply explores the development height of the "three zones" and the stress distribution law of the stope, which is helpful to reveal the multi-disaster synergistic control mechanism of the gangue pumping pillar filling roof.

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

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

[0033] Figure 2 is a front view structural schematic diagram of the composite structure double-layer flexible mold bag in the present application. Figure 1

[0034] The meanings of the various reference numerals in the drawings are as follows: 100 - composite structure double-layer flexible mold bag, 110 - inner nylon fiber film bag, 120 - pressure-bearing framework, 130 - outer nylon fiber film bag. ​

[0035] The specific content of the present application is further explained in detail in connection with the following examples. DETAILED DESCRIPTION

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

[0037] The specific embodiments of the present application are given below, it should be noted that the present application is not limited to the following specific embodiments, any equivalent transformation made on the basis of the technical solutions of the present application falls within the protection scope of the present application.

[0038] Embodiment:

[0039] The present embodiment gives a kind of coal mine underground gangue in situ pumping column filling mining multi-disaster collaborative control method, which comprises the following steps:

[0040] Step S1, the separation of coal and gangue obtains gangue powder particles:

[0041] The specific process of step S1 is: the raw coal mined from the coal mining face or the heading face is transported to the raw coal bin by the coal belt conveyor for temporary storage, and then part of the raw coal in the raw coal bin is transported to the chamber near the mining area by the raw coal transfer belt to crush and separate the coal and gangue, the separated coal is transported to the clean coal bin by the coal conveying belt, and the separated gangue is transported to the gangue crusher by the gangue conveying belt to form gangue powder particles after at least one crushing.

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

[0043] In step S1, the chamber near the mining area refers to a chamber opened in the special roadway of the coal mining face or a chamber with a certain scale.

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

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

[0046] Mix and stir the sulphoaluminate cement, water and gangue powder particles obtained in step S1 to form the gangue filling slurry.

[0047] In step S2, the mass ratio of sulphoaluminate cement, water and gangue powder particles 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 bulk density of the slurry is 1300 g / m 3 up to 1450 kg / m 3 .

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

[0052]

[0053] Step S3, calculating the filling strength required for the goaf roof q and the support strength of the pumping prop q 充填 , satisfying the constraint condition .

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

[0055] ;

[0056] In the formula:

[0057] q represents the filling strength required for the goaf roof, with the unit of MPa;

[0058] K represents the ratio of the overburden thickness of the support of the coal mining face prop to the mining height, preferably, K taking 4 to 8;

[0059] H represents the mining height, with the unit of m;

[0060] gamma represents the roof rock density, with the unit of kg / m 3 ;

[0061] g represents the gravitational acceleration, with the unit of m / s 2 .

[0062] In step S3, the support strength of the pumping prop q 充填 The calculation formula is:

[0063] ;

[0064] In the formula:

[0065] q 充填 represents the support strength of the pumping prop, with the unit of MPa;

[0066] P represents the working face prop resistance, with the unit of kN;

[0067] R represents the support area of the support, in m 2 ;

[0068] B represents the center distance of a single set of supports, in m;

[0069] represents the length of the top beam of the support, in m.

[0070] Step S4, the working face pushing length of the required pumping support filling support is equal to the working face length, i.e. the goaf forms a square, and the required filling strength of the goaf roof obtained in step S3 q and the support strength of the pumping support q 充填 Calculate the row spacing of the pumping support A .

[0071] The calculation formula of the row spacing of the pumping support A

[0072] ;

[0073] ;

[0074] In the formula:

[0075] A represents the row spacing between the centers of the pumping supports, A rounded, in m;

[0076] L represents the working face length, in m;

[0077] N represents the number of pumping supports required for the goaf;

[0078] q represents the required filling strength of the goaf roof, in MPa;

[0079] L 2 represents the goaf area, in m 2 ;

[0080] f represents the safety factor, preferably, f 1.1 to 1.2;

[0081] q 充填 represents the support strength of the pumping support, in MPa;

[0082] r represents the cross-sectional radius of the pumping support, in m.​

[0083] Step S5, construction of the pumping pillar:

[0084] In the goaf, the pumping pillar interval distance obtained according to step S4 A The composite double-layer flexible mold bag 100 is placed at intervals, and the gangue filling slurry obtained in step S2 is injected into each composite double-layer flexible mold bag 100 by a high-pressure pump to form a matrix-arranged pumping pillar.

[0085] In step S5, the construction sequence of the pumping pillar is as follows: in the manner of front mining and rear filling, the filling area is controlled to be greater than one pumping pillar interval distance A and less than two pumping pillar interval distances A along the mining direction. That is, the mining and the pumping pillar filling of the goaf generated by the mining are simultaneously performed.

[0086] In step S5, as shown in Figure 1 and Figure 2 , the composite double-layer flexible mold bag 100 includes an inner nylon fiber film bag 110 in a cylindrical structure, an outer nylon fiber film bag 130 in a cylindrical structure is coaxially sleeved outside the inner nylon fiber film bag 110, and a pressure-bearing framework 120 is fixedly sleeved between the outer ring wall of the inner nylon fiber film bag 110 and the inner ring wall of the outer nylon fiber film bag 130.

[0087] In the embodiment, the composite double-layer flexible mold bag 100 has the characteristics of high strength, flame retardance, anti-static, and side limit pressure increase, can be one-time injection molding and rapid forming, the inner nylon fiber film bag 110 and the outer nylon fiber film bag 130 wrap and self-adaptively maintain the pressure of the filling slurry, the pressure-bearing framework 120 self-bearingly applies pressure from the side limit, compared with other metal material templates, the weight is reduced by 62%, the resistance to side pressure of the composite double-layer flexible mold bag 100 is improved by 29% compared with a single mold bag, the pumping filling slurry is limited by the composite double-layer flexible mold bag 100, the lateral deformation is effectively controlled, the post-strength of the gangue filling slurry combination can be improved by more than 34% compared with the traditional pillar strength, and the rapid molding can be realized to meet the goaf filling demand under high mining intensity. The displacement sensor 140 can record the filling height and height change data of the composite double-layer flexible mold bag 100 in real time, and provide data support for the optimization of the material ratio in the later period.

[0088] In step S5, further, a displacement sensor is built-in at the top of the composite double-layer flexible mold bag 100, the displacement conditions of all the pumping pillars of the goaf are monitored, and the data are uploaded to the ground in real time through a communication cable. The displacement data are matched with different material ratios by collecting the data of the displacement sensor, and the material ratio is continuously optimized according to the actual situation on site.

Claims

1. A multi-disaster synergistic control method for coal mine underground gangue in-situ pumping columnar filling mining, characterized in that, The method comprises the following steps: Step S1, separating coal from gangue to obtain gangue powder particles; Step S2, preparation of gangue filling slurry: Mixing and stirring sulphoaluminate cement, water and the gangue powder particles obtained in step S1 to form a gangue filling slurry; Step S3, calculating the required filling strength of the goaf roof q and the support strength of the pumped prop q 充填 , satisfying the constraint condition ; Step S4, the required length of the working face advancing length of the pumping pillar filling support is equal to the length of the working face, that is, the goaf forms a square, and the required filling strength of the goaf roof obtained in step S3 q and the support strength of the pumping pillar q 充填 Calculate the row spacing between the pumping pillars A ; The pumping struts are spaced apart A The formula for calculating the distance between the struts is: ； ； In the formula: A denotes the center-to-center spacing of the pumping struts, A rounded to the nearest meter; L L represents the working face length, in m; N represents the number of pumping props required for the goaf; q represents the required filling strength of the goaf roof, in MPa; L 2 represents the area of the goaf, in m2 2 ; f represents a safety factor; q 充填 represents the support strength of the pumping struts in MPa; r R represents the cross-sectional radius of the pumping struts in m; Step S5, construction pumping support: The pumping pillar interval obtained according to step S4 in the goaf A The composite structure double-layer flexible mold bag (100) is arranged at intervals, the gangue filling slurry obtained in step S2 is injected into each composite structure double-layer flexible mold bag (100) by a high-pressure pump, and a matrix-arranged pumping pillar is formed. In step S5, the composite structure double-layer flexible mold bag (100) comprises an inner nylon fiber membrane bag (110) in a cylindrical structure, and an outer nylon fiber membrane bag (130) in a cylindrical structure is coaxially sleeved outside the inner nylon fiber membrane bag (110), and a pressure-bearing framework (120) is fixedly sleeved between the outer ring wall of the inner nylon fiber membrane bag (110) and the inner ring wall of the outer nylon fiber membrane bag (130).

2. The multi-disaster synergy control method for coal underground gangue in-situ pumping columnar filling mining according to claim 1, characterized in that, In step S2, the mass ratio of the sulphoaluminate cement, water and gangue powder particles is 1:3:

3.

3. The multi-disaster synergy control method for coal underground gangue in-situ pumping columnar filling mining according to claim 1, characterized in that, In step S3, the required filling strength of the goaf roof q The calculation formula is: ； In the formula: q represents the required filling strength of the goaf roof, in MPa; K represents the ratio of the overburden thickness of the support of the coal mining face to the mining height; H represents the height of the cut, in m; γ represents the density of the roof rock in kg / m 3 ; g denotes the acceleration due to gravity, in m / s 2 .

4. The multi-disaster synergy control method for coal mine underground gangue in-situ pumping columnar filling mining according to claim 1, characterized in that, In step S3, the support strength of the pumping struts q 充填 The calculation formula is: ； In the formula: q 充填 represents the support strength of the pumping struts in MPa; P This indicates the resistance of the working face support, expressed in kN. R Support area of the support, in m 2 ; B represents the center distance of a single set of supports, in m; represents the length of the top beam of the support, in m.

5. The multi-disaster synergy control method for coal mine underground gangue in-situ pumping columnar filling mining according to claim 1, characterized in that, The specific process of step S1 is as follows: raw coal mined from a coal mining face or a tunneling face is temporarily stored in a mining area raw coal bin through a coal mining belt, and then part of the raw coal in the raw coal bin is transported to a chamber near the mining area through a raw coal transfer belt to crush and separate the coal and gangue, the separated coal is transported to a clean coal bin through a coal conveying belt, and the separated gangue is transported to a gangue crusher through a gangue conveying belt to form gangue powder particles through at least one crushing.

6. The multi-disaster synergy control method for coal underground gangue in-situ pumping columnar filling mining of claim 5, characterized in that, In step S1, the particle size of the gangue powder particles is less than 10 mm.

7. The multi-disaster synergy control method for coal mine underground gangue in-situ pumping columnar filling mining according to claim 1, characterized in that, In step S5, the construction sequence of the pumping supports is as follows: the pumping supports are advanced synchronously in the manner of front mining and rear back filling, and the length of the backfilling area along the mining direction is controlled to be greater than the spacing between one pumping support. A Less than the row spacing between the two pumping supports A .

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