A method for determining the spatial alignment of a railway in a goaf of a coal mine

Abstract

A method for determining the spatial alignment of railway in goaf area, so as to ensure that the railway engineering in complex goaf area passes through the section with lower disaster risk, greatly reduce the line selection cost and save the survey period, and realize the economy and rationality of the engineering to the greatest extent. It includes the following steps: ① In the lowest mining range of the goaf area of the coal mine, near the railway engineering section, vertically arrange the main axis section of the control goaf area; determine the position of the goaf area of the coal mine and the lowest mining elevation; at the lowest mining elevation position of the goaf area in the profile, use the boundary angle to determine the influence range of the goaf area; determine the width of the enclosure belt according to the table below according to the protection level of the protected railway object; determine the building boundary range of the railway protection object according to the type of railway engineering; calculate the goaf area avoidance safety width W from the railway engineering building boundary width; determine the spatial alignment of the railway, so that the railway tunnel passes outside the avoidance safety width of the goaf area.

Description

Technical Field

[0001] The present invention relates to a method for disaster reduction and route selection in mountain railway engineering, and particularly to a method for determining the spatial alignment of railway engineering based on the risk zoning of coal mine goafs. Background Art

[0002] Disaster reduction and route selection is a risk decision-making process under the condition of uncertain action of natural disasters on the whole life cycle of the line project. The disaster reduction and route selection of railways in complex coal mine goafs is a risk decision-making process for the line scheme and engineering settings under the condition of uncertain action of goaf disasters on the whole life cycle of railway engineering.

[0003] A coal mine goaf is an area or scope where, after large areas of underground coal seams are mined out, the upper part of the coal seam loses support, the balance condition is destroyed, and the rock mass above the goaf will then undergo displacement, cracking, fragmentation and caving, until the overall subsidence and bending of the overlying strata cause surface deformation and damage. In the case of full mining or near-full mining, the angle between the connecting line of the basin boundary point (subsidence value of 10 mm) on the main section of the surface movement basin to the goaf boundary and the horizontal line on the side of the coal pillar is the goaf boundary angle; in the case of full mining or near-full mining, on the main section of the movement basin, the angle between the connecting line of the outermost critical deformation point on the surface and the goaf boundary point and the horizontal line on the side of the coal wall. The protection scope of railway engineering should include the protected object and its protective belt.

[0004] Therefore, when determining the spatial alignment of railways in goafs, the distribution range and the lowest mining elevation of the goaf should be determined, the deformation and damage range of the goaf and the width of the protective belt should be divided, and by reasonably determining the line elevation and alignment, a position with relatively lower risk should be selected to pass through, so as to reduce the risk of the goaf to railway engineering. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for determining the spatial alignment of railways in coal mine goafs, so as to ensure that railway engineering in complex goafs passes through sections with lower disaster risks, greatly reduce the route selection cost and save the exploration construction period, and maximize the economy and rationality of the project.

[0006] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0007] Invent a method for determining the spatial alignment of railways in coal mine goafs, including the following steps:

[0008] 1. A method for determining the spatial alignment of railways in coal mine goafs, including the following steps:

[0009] ① In the lowest mining range of the coal mine goaf, adjacent to the railway engineering section, arrange a controlled goaf main axis section perpendicular to the coal seam strike;

[0010] ②Determine the location of the coal mine goaf and the lowest mining elevation of the goaf through data collection, underground measurement, exploration and testing;

[0011] ③At the lowest mining elevation position of the goaf in the profile, determine the influence range of the goaf using the boundary angle;

[0012] ④Determine the width of the goaf protection belt according to the protection level of the protected railway object as follows:

[0013]

[0014] ⑤Determine the building limit range of the railway protection object according to the type of railway project. For embankments, the protection object is 1 m outside the toe of the embankment slope on both sides; for cuttings, the protection object is 1 m outside the edge of the cutting top on both sides; for bridges, the protection object is 1 m outside the outer edge of the foundation; for tunnels, the protection object is 1 m outside the building limit;

[0015] ⑥The goaf avoidance safety width W consists of three parts: the width of the railway project building limit, the width of the protection belt 6, and the influence width 5 of the goaf, and is calculated according to the following formula:

[0016] W = cotβ0·Y + S + A

[0017] Where: A is the width of the building limit; S is the width of the protection belt; cotβ0·Y is the influence width of the goaf; Y is the vertical distance between the center of the railway project and the lowest mining elevation of the coal mine goaf; β0 is the downhill boundary angle of the coal seam;

[0018] ⑦Judge through the relative position relationship between the railway project and the lowest mining elevation of the coal mine goaf. When the horizontal distance between the railway project and the lowest mining elevation of the coal mine goaf is less than the goaf avoidance safety width, it indicates that the railway project is within the risk range of the goaf. Through the coordinated cooperation of the spatial line position plane position adjustment and the spatial line position vertical section position adjustment, the railway tunnel passes outside the goaf avoidance safety width; when the spatial line position plane position adjustment is limited, lower the elevation of the preset tunnel A through the section and displace it to the adjusted tunnel position to pass; when the spatial line position vertical section position adjustment is limited, move the position of the preset tunnel A through the plane and displace it to the adjusted tunnel position to pass.

[0019] In step ③, the boundary angle is divided into the downhill boundary angle β0, the uphill boundary angle γ0, and the strike boundary angle δ0 according to different directions along the coal seam, and is calculated using the following formula according to the movement angle:

[0020] β0 = β - 15×(1 - 0.01α)

[0021] γ0 = γ - 15

[0022] δ0 = δ - 15

[0023] Where: β is the downward movement angle, γ is the upward movement angle, δ is the strike movement angle, and α is the coal seam dip angle, which is determined by looking up the table according to the overlying rock lithology as follows:

[0024]

[0025] The beneficial effects of the present invention are as follows. From the perspective of disaster reduction and route selection for railway engineering, the avoidance safety width of the goaf is divided into three parts: the boundary width of railway engineering buildings, the width of the protective belt, and the influence width of the goaf. Reasonable parameters are determined, and through the coordinated cooperation of the spatial line position plane and vertical section, the harm caused by the goaf to railway engineering is minimized, and problems such as major casualties, loss of life and property, and ecological environment damage are avoided. The route selection cost is greatly reduced, the exploration period is saved, and it is ensured that the railway engineering in the complex goaf area passes through the section with lower disaster risks, maximizing the economy and rationality of the project. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] This specification includes the following two drawings:

[0027] Figure 1 It is a diagram showing the relationship between the goaf profile and the position of railway engineering;

[0028] Figure 2 It is a diagram showing the relationship between the goaf zoning and the position of the tunnel.

[0029] The figure shows the names of the parts shown and the corresponding marks: coal mine goaf 1, the lowest mining elevation of the goaf 2, coal seam 3, boundary angle of the controlled goaf 4, influence width of the goaf 5, width of the protective belt of the goaf 6, boundary width of railway engineering buildings 7, railway engineering 9, preset tunnel A, adjusted tunnel B, main shaft section of the goaf C, vertical distance Y between the center of the railway engineering and the lowest mining elevation of the coal mine goaf, horizontal distance X between the center of the railway engineering and the lowest mining elevation of the coal mine goaf, and avoidance safety width of the goaf W. DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention will be further described below in conjunction with the drawings and embodiments.

[0031] Refer to Figure 1 and Figure 2 , a method for determining the railway spatial line position of a coal mine goaf according to the present invention includes the following steps:

[0032] ① In the lowest mining range of the coal mine goaf 1, near the railway engineering 9 section, arrange the main shaft section C of the controlled goaf vertically along the strike of the coal seam;

[0033] ② Determine the position of the coal mine goaf 1 and the lowest mining elevation 2 of the goaf through data collection, underground measurement, and exploration and testing;

[0034] ③At the lowest mining elevation 2 of the goaf in the cross-section, the boundary angle 4 is used to determine the influence range of the goaf;

[0035] ④According to the protection level of the protected railway object, the width 6 of the goaf protection zone is determined according to the following table:

[0036]

[0037]

[0038] ⑤According to the type of railway project, the building limit range of the railway protection object is determined. Among them, for embankments, the protection object is 1 m outside the toe of the embankment slope on both sides; for cuttings, the protection object is 1 m outside the edge of the cutting top on both sides; for bridges, the protection object is 1 m outside the outer edge of the foundation; for tunnels, the protection object is 1 m outside the building boundary;

[0039] ⑥The avoidance safety width W of the goaf consists of three parts: the width of the railway project building boundary, the width 6 of the protection zone, and the influence width 5 of the goaf, and is calculated according to the following formula:

[0040] W = cotβ0·Y + S + A

[0041] In the formula: A is the width of the building boundary; S is the width of the protection zone; cotβ0·Y is the influence width of the goaf; Y is the vertical distance between the center of the railway project and the lowest mining elevation of the coal mine goaf; β0 is the downhill boundary angle of the coal seam;

[0042] ⑦Through the judgment of the relative position relationship between the railway project and the lowest mining elevation of the coal mine goaf, when the horizontal distance X between the railway project and the lowest mining elevation of the coal mine goaf is less than the avoidance safety width W of the goaf, it indicates that the railway project is within the risk range of the goaf. Through the coordinated cooperation of the spatial line position horizontal position adjustment and the spatial line position vertical section position adjustment, the railway tunnel passes outside the avoidance safety width of the goaf; when the adjustment of the spatial line position horizontal position is limited, the elevation of the preset tunnel A is reduced through the section, and it is displaced to the position of the adjusted tunnel B to pass; when the adjustment of the spatial line position vertical section position is limited, the position of the preset tunnel A is moved horizontally, and it is displaced to the position of the adjusted tunnel B to pass.

[0043] In step ③, the boundary angle 4 is divided into the downhill boundary angle β0, the uphill boundary angle γ0, and the strike boundary angle δ0 according to different directions along the coal seam, and is calculated by the formula according to the following movement angles:

[0044] β0 = β - 15×(1 - 0.01α)

[0045] γ0 = γ - 15

[0046] δ0 = δ - 15

[0047] Where: β is the downhill movement angle, γ is the uphill movement angle, δ is the strike movement angle, and α is the coal seam dip angle, which is determined by looking up the table according to the following overlying rock lithology:

[0048]

[0049] Example: Determination of the spatial alignment of a tunnel on the connecting line of a railway hub passing through a goaf area

[0050] Refer to Figure 1 and Figure 2 A tunnel on the connecting line of a railway hub runs through the shale intercalated with coal measures strata of the Xujiahe Formation (T3xj), with a rock stratum dip angle of about 45°. There have been multiple coal mine exploitations in different periods in the past. The goaf is located on the left side of the line. The lowest mining elevation of the goaf is 240m, the track bottom elevation of the tunnel is 275m, the goaf is about 40m horizontally and about 35m vertically from the left side of the tunnel. It is a single-track tunnel with a tunnel width of 7m.

[0051] 1. Calculation of the goaf influence width

[0052] According to the "Table for Determining General Surface Movement Parameters According to Overlying Rock Lithology", the overlying rock type is soft rock to extremely soft rock. The downhill movement angle β = δ - (0.3 - 0.5)α = 70 - 0.3×45 = 56.5°. The downhill boundary angle β0 = β - 15×(1 - 0.01×α) = 56.5 - 15×(1 - 0.01×45) = 48.25°. The goaf influence width = cotβ0×Y = cot48.25°×35 = 31.24m.

[0053] 2. Determination of the protective belt width

[0054] For a national Class I railway, the protective belt width is taken as 20m.

[0055] 3. Determination of the building limit width

[0056] The tunnel project takes 1m outside the building boundary as the protected object, and the half-width of the tunnel is 3.5m, with a total of 4.5m.

[0057] In summary, the horizontal avoidance safety width of the goaf = 31.24m + 20m + 4.5m = 55.74m. Currently, the tunnel project is 40m to the right of the goaf, indicating that the railway project is within the risk range of the goaf. Therefore, the tunnel project is horizontally moved 20m to the right, thus avoiding construction risks and long-term operation risks.

Claims

1. A method for determining the spatial alignment of a railway in a goaf of a coal mine, comprising the following steps: ① At the lowest mining range of the coal mine goaf (1), in the section near the railway project (9), arrange a control goaf main axis profile (C) perpendicular to the coal seam strike; ② Determine the location of the coal mine goaf (1) and the lowest mining elevation (2) of the goaf through data collection, underground measurement, and exploration and testing; ③ At the position of the lowest mining elevation (2) of the goaf in the profile, use the boundary angle (4) to determine the influence range of the goaf; ④ Determine the width of the goaf protection zone (6) according to the protection level of the protected railway object as shown in the following table: ⑤ Determine the building limit range of the railway protection object according to the type of railway project. For an embankment, the protection object is 1 m outside the toe of the embankment slope on both sides; for a cutting, the protection object is 1 m outside the edge of the cutting top on both sides; for a bridge, the protection object is 1 m outside the outer edge of the foundation; for a tunnel, the protection object is 1 m outside the building limit; ⑥ The goaf avoidance safety width (W) consists of three parts: the width of the railway project building limit (7), the width of the protection zone (6), and the influence width (5) of the goaf, and is calculated according to the following formula: W = cotβ0·Y + S + A Where: A is the width of the building limit; S is the width of the protection zone; cotβ0·Y is the influence width of the goaf; Y is the vertical distance between the center of the railway project and the lowest mining elevation of the coal mine goaf; β0 is the downhill boundary angle of the coal seam; ⑦ Through the judgment of the relative position relationship between the railway project and the lowest mining elevation of the coal mine goaf, when the horizontal distance (X) between the railway project and the lowest mining elevation of the coal mine goaf is less than the goaf avoidance safety width (W), it indicates that the railway project is within the risk range of the goaf. Through the coordinated cooperation of the adjustment of the plane position of the spatial alignment and the adjustment of the vertical section position of the spatial alignment, the railway tunnel passes outside the goaf avoidance safety width; when the adjustment of the plane position of the spatial alignment is limited, the elevation of the preset tunnel (A) is reduced through the section, and it is displaced to the position of the adjusted tunnel (B) to pass through; when the adjustment of the vertical section position of the spatial alignment is limited, the position of the preset tunnel (A) is moved horizontally, and it is displaced to the position of the adjusted tunnel (B) to pass through.

2. The method for determining the spatial alignment of a railway in a mined - out area of a coal mine according to claim 1, wherein: In the said step ③, the boundary angle (4) is divided into the downhill boundary angle β0, the uphill boundary angle γ0, and the strike boundary angle δ0 according to different directions along the coal seam, and is calculated by the formula according to the following movement angles: β0＝β-15×(1-0.01α) γ0 = γ - 15 δ0 = δ - 15 Where: β is the downhill movement angle, γ is the uphill movement angle, δ is the strike movement angle, α is the coal seam dip angle, and is determined by looking up the table according to the following overlying rock lithology:

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