CN105257293B - A kind of shallow embedding gas transmission line push the recovery method of coal - Google Patents

Abstract

The invention discloses a mining method for pressing coal under a shallow buried gas transmission pipeline, which comprises the following steps: (1) establishing a surface subsidence curve equation W to predict the subsidence of the surface along the pipeline direction after resource mining; (2) calculating The bending moment and the maximum bending stress of the shallow buried gas pipeline; (3) determine the protection range of the shallow buried gas pipeline; (4) erect a suspension bridge along the direction of the pipeline according to the protection range determined in step 3, and lift the pipeline in the subsidence area (5) Mining the coal resources under the pipeline in a conventional way, and removing the suspension bridge after the subsidence is stable, and repeating the above steps before the mining of the next working face, until all the resources in the mining area are recovered. According to the influence of dynamic deformation on the shallow buried gas transmission pipeline during the mining of coal resources, the present invention can protect the shallow buried gas transmission pipeline by using the method of suspending the pipeline with a suspension bridge, so that the stagnant pressure under the pipeline can be mined by adopting the normal mining method coal resources.

Description

A mining method for pressing coal under a shallow buried gas pipeline

technical field

The invention relates to a mining method of compressed coal, in particular to a mining method of compressed coal under a shallow buried gas transmission pipeline, belonging to the field of coal mining.

Background technique

Surface subsidence induced by coal mining will cause great damage to the surface environment and structures. my country's long-distance gas pipelines pass through the distribution areas of major coal fields in my country. With the continuous expansion of coal mining areas, more and more gas pipelines will be affected by mining subsidence. The high-pressure gas in the pipeline is flammable and explosive. Once the gas leaks or the pipeline breaks, it will easily cause a major accident, causing heavy casualties and property losses, and seriously endangering social production and the national economy.

Most of the existing gas pipelines are shallow-buried gas pipelines, and the protection method is mainly to leave protective coal pillars. This method is in the process of coal mining, according to the shallow buried gas pipeline and the occurrence characteristics of coal seam, it is estimated that the pipeline protects the coal pillar range, and the protective coal pillar is left to prevent mining, so that the shallow buried gas pipeline is not subject to coal mining subsidence Impact. This method mainly has the following disadvantages:

(1) The layout of the shallow buried gas pipeline relative to the coal mining face is random, and the pipeline protection coal pillar in coal mining will have a great impact on the layout of the coal mining face and the way of coal mine development in the mining area.

(2) Usually, the protective coal pillars along the shallow buried gas pipeline are relatively wide, and generally the width of the protective coal pillars is about 1000m, which will cause a lot of waste of coal resources.

(3) The stagnation of coal resources along the shallow buried gas pipeline will have a huge impact on the production and economic benefits of the mining area, and affect the sustainable development of the mining area.

Contents of the invention

The object of the present invention is to provide a method for mining compressed coal under a shallow buried gas transmission pipeline, which can not only effectively protect the gas transmission pipeline, but also efficiently exploit the compressed coal under the pipeline.

In order to achieve the above object, a mining method for pressing coal under a shallow buried gas pipeline comprises the following steps:

a. Determine the movement and deformation parameters of the shallow buried gas pipeline according to the observation data of the surface movement after the recovery of coal resources in other areas of the mining area, and use the probability integral method to establish the surface subsidence curve equation W to predict the subsidence of the surface along the direction of the pipeline after resource mining;

b. Calculate the bending moment and maximum bending stress of the buried pipeline according to the above ground subsidence curve equation. According to the bending theory of the continuous beam, the calculation equation of the bending moment of the buried pipeline can be obtained as:

In the formula, E is the tensile elastic modulus of the pipeline, I is the moment of inertia of the pipeline section, and the maximum bending stress of the pipeline is:

where d is the radius of the pipeline section;

c. Determine the axial tensile stress of the shallow buried pipeline according to the maximum bending stress, and determine the protection range of the shallow buried gas pipeline in combination with the allowable tensile stress of the pipeline. The formula for calculating the axial tensile stress along the buried pipeline in the subsidence area is:

σ _n (l) = σ _n0 + σ (l)

In the formula, σ _n0 is the initial axial tensile stress of the pipeline, which can be obtained according to the internal pressure and working state of the pipeline. The allowable tensile stress of the pipeline is [σ]. When σ _n (l) > [σ], the axial direction of the corresponding position pipeline The tensile stress exceeds the allowable tensile stress, thus determining the range of protective measures for buried pipelines; when σ _n (l)<[σ], the axial tensile stress of the pipeline at the corresponding position is less than the allowable tensile stress, where the pipeline No protective measures are required;

d. According to the protection range determined in step c, erect a suspension bridge along the direction of the pipeline, and lift the pipeline in the subsidence area;

e. Mining the compressed coal under the pipeline in a conventional way until the resource recovery of the working face is completed;

f. Remove the suspension bridge after the surface subsidence of the above working face is stable; repeat steps a to e to complete the mining of coal resources in the next working face; continue to mine coal resources in this way until all the working face resources in the mining area are mined.

According to the influence of dynamic deformation on the shallow buried gas transmission pipeline during mining of coal resources, the present invention adopts the suspension bridge suspension pipeline to protect the shallow buried gas transmission pipeline, so that the hysteresis under the pipeline can be mined by conventional mining methods Coal resource. The suspension bridge is easy to erect, and the main components can be reused; the ground subsidence is stable, and after the suspension bridge is dismantled, the pipeline itself has certain tensile characteristics, so there will be no sudden deformation. Under normal circumstances, there is no need for filling support, and the process is relatively simple; the erection of the suspension bridge The increased cost is less than 1% of the total production cost, but the huge amount of compressed coal under the pipeline can be mined, which has extremely high economic benefits.

Description of drawings

Fig. 1 is the schematic diagram of the specific embodiment of the present invention;

Fig. 2 is the schematic diagram of support seat among the present invention;

In the figure: 1. Support pier, 2. Suspension steel cable, 3. Support pier foundation, 4. Pipeline, 5. Sling, 6. Pipeline support seat, 61. Bottom bracket, 62. Upper cover, 63. Groove , 64, bolt, 65, lifting lug.

detailed description

The present invention will be further described below in conjunction with accompanying drawing.

A mining method for pressing coal under a shallow buried gas pipeline, comprising the following steps:

a. Determine the movement and deformation parameters of the shallow buried gas pipeline according to the observation data of the surface movement after the recovery of coal resources in other areas of the mining area, and use the probability integral method to establish the surface subsidence curve equation W to predict the subsidence of the surface along the direction of the pipeline after resource mining;

b. Calculate the bending moment and maximum bending stress of the buried pipeline according to the above ground subsidence curve equation. According to the bending theory of the continuous beam, the calculation equation of the bending moment of the buried pipeline can be obtained as:

In the formula, E is the tensile elastic modulus of the pipeline, I is the moment of inertia of the pipeline section, and the maximum bending stress of the pipeline is:

where d is the radius of the pipeline section;

c. Determine the axial tensile stress of the shallow buried pipeline according to the maximum bending stress, and determine the protection range of the shallow buried gas pipeline in combination with the allowable tensile stress of the pipeline. The formula for calculating the axial tensile stress along the buried pipeline in the subsidence area is:

σ _n (l) = σ _n0 + σ (l)

In the formula, σ _n0 is the initial axial tensile stress of the pipeline, which can be obtained according to the internal pressure and working state of the pipeline. The allowable tensile stress of the pipeline is [σ]. When σ _n (l) > [σ], the axial direction of the corresponding position pipeline The tensile stress exceeds the allowable tensile stress, thus determining the range of protective measures for buried pipelines; when σ _n (l)<[σ], the axial tensile stress of the pipeline at the corresponding position is less than the allowable tensile stress, where the pipeline No protective measures are required;

d. According to the protection range determined in step c, erect a suspension bridge along the direction of the pipeline, and lift the pipeline in the subsidence area;

e. Mining the compressed coal under the pipeline in a conventional way until the resource recovery of the working face is completed;

f. Remove the suspension bridge after the surface subsidence of the above working face is stable; repeat steps a to e to complete the mining of coal resources in the next working face; continue to mine coal resources in this way until all the working face resources in the mining area are mined.

According to the influence of dynamic deformation on the shallow buried gas transmission pipeline during mining of coal resources, the present invention adopts the suspension bridge suspension pipeline to protect the shallow buried gas transmission pipeline, so that the hysteresis under the pipeline can be mined by conventional mining methods Coal resource. The suspension bridge is easy to erect, and the main components can be reused; the ground subsidence is stable, and after the suspension bridge is dismantled, the pipeline itself has certain tensile characteristics, so there will be no sudden deformation. Generally, no filling support is required, and the process is relatively simple; erection of the suspension bridge The increased cost is less than 1% of the total production cost, but the huge amount of compressed coal under the pipeline can be mined, which has extremely high economic benefits.

The optimal parameters of surface movement and deformation in step a include: subsidence coefficient, horizontal movement coefficient, inflection point offset, influence angle of coal seam mining, elastic modulus and strength of rock mass, these optimal parameters can fully reflect surface movement in subsidence area and deformation.

Fig. 1 is a preferred embodiment of the suspension bridge described in step d, comprising a supporting pier 1 and a suspension steel cable 2, the supporting pier 1 is arranged at both ends of the area to be protected by the gas pipeline 4, and a supporting pier is arranged below it The foundation 3 and the support pier foundation 3 are arranged symmetrically on both sides of the gas transmission pipeline 4, the gas transmission pipeline 4 passes between the two support pier foundations 3, the suspension steel cable 2 is erected between the two support piers 1, and the suspension cable 5 is suspended on the suspension steel cable 2. The supporting pier 1 adopts a cement structure, and the suspension bridge is low in cost.

Further, the sling 5 lifts the gas transmission pipeline 4 through the pipeline support base 6 , and the pipeline support base 6 can effectively protect the gas transmission pipeline 4 .

Fig. 2 is a preferred solution of the pipeline support base 6, including a bottom bracket 61 and an upper cover 62, the bottom bracket 61 and the upper cover 62 are respectively provided with grooves 63 for arranging pipelines, and the bottom bracket 61 and the upper cover 62 pass through The bolts 64 are connected, and the upper cover 62 is provided with lifting lugs 65; it is convenient and stable to lift the gas pipeline 4 like this. It is also possible not to use the loam cake, and directly set some lifting lugs on the upper edge of the base, which requires a corresponding number of slings.

Claims (5)

1. A mining method for pressing coal under a shallow buried gas pipeline, characterized in that it may further comprise the steps: a. Determine the movement and deformation parameters of the shallow buried gas pipeline according to the observation data of the surface movement after the recovery of coal resources in other areas of the mining area, and use the probability integral method to establish the surface subsidence curve equation W to predict the subsidence of the surface along the direction of the pipeline after resource mining; b. Calculate the bending moment and maximum bending stress of the buried pipeline according to the above ground subsidence curve equation. According to the bending theory of the continuous beam, the calculation equation of the bending moment of the buried pipeline can be obtained as: <mrow><mi>M</mi><mrow><mo>(</mo><mi>l</mi><mo>)</mo></mrow><mo>=</mo><mi>E</mi><mi>I</mi><mfrac><mrow><msup><mi>d</mi><mn>2</mn></msup><mi>W</mi></mrow><mrow><msup><mi>dl</mi><mn>2</mn></msup></mrow></mfrac></mrow> In the formula, E is the tensile elastic modulus of the pipeline, I is the moment of inertia of the pipeline section, and the maximum bending stress of the pipeline is: <mrow><mi>&amp;sigma;</mi><mrow><mo>(</mo><mi>l</mi><mo>)</mo></mrow><mo>=</mo><mfrac><mrow><mi>M</mi><mrow><mo>(</mo><mi>l</mi><mo>)</mo></mrow><mi>d</mi></mrow><mi>I</mi></mfrac></mrow> where d is the radius of the pipeline section; c. Determine the axial tensile stress of the shallow buried pipeline according to the maximum bending stress, and determine the protection range of the shallow buried gas pipeline in combination with the allowable tensile stress of the pipeline. The formula for calculating the axial tensile stress along the buried pipeline in the subsidence area is: σ _n (l) = σ _n0 + σ (l) In the formula, σ _n0 is the initial axial tensile stress of the pipeline, which can be obtained according to the internal pressure and working state of the pipeline. The allowable tensile stress of the pipeline is [σ]. When σ _n (l) > [σ], the axial direction of the corresponding position pipeline The tensile stress exceeds the allowable tensile stress, thus determining the range of protective measures for buried pipelines; when σ _n (l)<[σ], the axial tensile stress of the pipeline at the corresponding position is less than the allowable tensile stress, where the pipeline No protective measures are required; d. According to the protection range determined in step c, erect a suspension bridge along the direction of the pipeline, and lift the pipeline in the subsidence area; e. Mining the compressed coal under the pipeline in a conventional way until the resource recovery of the working face is completed; f. Remove the suspension bridge after the surface subsidence of the above working face is stable; repeat steps a to e to complete the mining of coal resources in the next working face; continue to mine coal resources in this way until all the working face resources in the mining area are mined. 2. The mining method for pressing coal under the shallow buried gas pipeline according to claim 1, wherein the preferred parameters of surface movement and deformation in the step a are: subsidence coefficient, horizontal movement coefficient, inflection point offset distance, influence angle of coal seam mining, elastic modulus and strength of rock mass. 3. The mining method of pressing coal under the shallow buried gas pipeline according to claim 2, wherein the suspension bridge in the step d comprises a support pier (1) and a suspension steel cable (2), and the support The piers (1) are arranged at both ends of the area to be protected on the gas transmission pipeline (4), and the supporting pier foundations (3) are arranged below them, and the supporting pier foundations (3) are arranged symmetrically on both sides of the gas transmission pipeline (4). The pipeline (4) passes between the two support pier foundations (3); the suspension steel cable (2) is erected between the two support piers (1), and the pipeline (4) is suspended on the Hang on the steel cable (2). 4. The coal mining method under the shallow buried gas pipeline according to claim 3, characterized in that the gas pipeline (4) is hoisted by the sling (5) through the pipeline support seat (6). 5. The mining method for pressing coal under shallow buried gas pipelines according to claim 4, characterized in that, the pipeline support seat (6) comprises a bottom support (61) and an upper cover (62), and the bottom The support (61) and the upper cover (62) are respectively provided with grooves (63) for placing the gas pipeline (4), the bottom support (61) and the upper cover (62) are connected by bolts (64), and the upper cover ( 62) hanger (65) is set.