Method for soil and water conservation of surface river affected by coal mining

Abstract

The present application belongs to the field of water conservancy facilities and construction, and particularly relates to a method for water and soil conservation of a ground river affected by coal mining, comprising a. damming and draining before mining, b. laying pipes and setting adjustable supports, c. water isolation and drainage and adjusting the adjustable supports during mining, d. sealing surface fissures and backfilling and compacting the riverbed after mining; the adjustable supports and the drainage pipes are recovered, and the river returns to normal. The present application does not cause waste of water resources, can normally supply water for agricultural and pastoral production, and is suitable for projects with small height difference between the upper and lower reaches of the river. The adjustable supporting feet designed in the present application can effectively adapt to the surface horizontal movement and subsidence law, so that they can always produce appropriate supporting effect on the drainage pipes, ensuring normal water flow between the upstream and downstream of the river. The present application uses waterproof sandbags to prevent the influence of rainwater on the working face during mining, and the sealing of the riverbed fissures is placed after the surface subsidence and deformation is stable after mining, and the sealing effect of the riverbed fissures can be ensured by the specially designed sealing mode.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of water conservancy facilities and construction, and particularly relates to a method for water and soil conservation of a ground river affected by coal mining. BACKGROUND

[0002] The northwest region is short of water resources, but is rich in mineral resources, especially coal resources. Coal mining can cause damage to the stratum, and cracks in the stratum, and subsidence on the ground. When the buried depth of coal is relatively shallow, the cracks can penetrate to the ground, causing the water in the ground valley to flow into the mine, resulting in water loss and affecting the safety production of the mine.

[0003] For this situation in the northwest region, there are many construction experiences that can be used for reference, such as the water prevention and control scheme for fully mechanized working face passing through the valley implemented by Liangshuijing Coal Mine, and the water prevention and control scheme for thin-bedded rock thick coal seam passing through the valley implemented by Chai'gou Coal Mine. The main idea is to build a dam before mining to intercept the water flow, and to discharge the water flow in the downstream to the goaf to discharge the water in the valley; to seal the cracks in the stratum during mining to prevent a large amount of water from flowing into the working face in the rainy season; and to backfill after mining to restore the original appearance of the valley. The above construction examples provide a good reference, but the engineering conditions of different projects are different, and the existing technical scheme cannot be directly copied, and the actual engineering conditions need to be adjusted adaptively.

[0004] The difference between the engineering situation of the present application and the existing engineering mainly lies in that the drop of the river is small, and a water dam cannot be set to discharge all the water in the downstream, the river water is used for irrigation of agriculture and animal husbandry, and belongs to an important water conservancy project, and cannot be cut off for a long time. At the same time, in the existing water prevention and control scheme, all the water in the downstream is discharged into the goaf, causing waste of water resources, and the river downstream cannot be used for irrigation of agriculture and animal husbandry during coal mining, causing production impact and economic loss to the downstream agriculture and animal husbandry. SUMMARY

[0005] The present application aims to solve the problems of waste of water resources, impact on agricultural and pastoral production, and poor adaptability to terrain drop during the working face passing through the valley, and proposes a method for water and soil conservation of a ground river affected by coal mining, which does not cause waste of water resources, can normally carry out agricultural and pastoral production, and is suitable for projects with small drop between the upstream and downstream of the river, mainly including the following steps:

[0006] a. damming and draining before mining: building an upstream dam on the upstream of the river outside the mining influence range of the working face, and building a downstream dam on the downstream of the river; reserving a water passage on the dam, and setting a large-diameter steel pipe in the water passage, and setting a valve on the large-diameter steel pipe, closing the valve to discharge the water in the river section between the upstream dam and the downstream dam;

[0007] b. pipe laying and adjustable support setting: laying drainage pipe section by section, connecting upstream and downstream of the river through large-diameter steel pipes and drainage pipes; the drainage pipes are made of hard pipes and are arranged flat, with a laying height higher than the riverbed and flush with the large-diameter steel pipes; an adjustable support is arranged between the riverbed and the drainage pipe, which can be extended and retracted to adapt to the subsidence of the riverbed caused by the working face mining, and the adjustable support and the horizontal movement and horizontal movement difference of the riverbed at different positions can make the adjustable support always support the drainage pipe during the working face mining; after connecting the large-diameter steel pipes upstream and downstream of the river through the drainage pipes, the valve is opened;

[0008] c. water isolation, drainage and adjustable support adjustment: laying waterproof sandbags on both banks of the river before the working face mining reaches the position of the river; when the working face mining reaches the section affecting the river, the water around the river is isolated from the river through the waterproof sandbags; at the same time, drainage pumps are added to the working face to drain the water flowing into the working face from the surface fissures; the adjustable support changes position due to mining, and the telescopic rod is adjusted adaptively to make the adjustable support always support the drainage pipe;

[0009] d. post-mining surface fissure plugging, riverbed backfilling and compaction; closing the valve, recovering the adjustable support and the drainage pipe, and opening the valve after recovery to restore the river to normal.

[0010] Further description of the above technical solutions:

[0011] In step a, the upstream dam and the downstream dam are both higher than the highest surface of the river by a certain height; the height center of the water pass is lower than the average water level of the river in normal years, and the diameter and number of the water pass meet the water flow demand.

[0012] Further description of the above technical solutions:

[0013] In step b, the adjustable support includes four support piles, two in front and two in back, the connecting line of the two front support piles is parallel to the connecting line of the two back support piles, and both are parallel to the width direction of the working face; a connecting base is arranged at the upper center of each support pile; a U-shaped rod is arranged on two connecting bases in the same width direction, the two ends of the U-shaped rod are respectively rotatably connected to the two connecting bases, two straight rods are respectively arranged on two connecting bases in the same width direction, one end of each straight rod is rotatably connected to the two connecting bases, and the other end is rotatably connected to the crossbar part of the U-shaped rod; two telescopic rods are arranged on the crossbar part of the U-shaped rod, one end of each telescopic rod is rotatably connected to the crossbar part of the U-shaped rod, and the other end is connected to a clamp; the telescopic rod and the clamp are connected through a spherical hinge or fixedly connected to the clamp; the clamp can rotate circumferentially relative to the drainage pipe.

[0014] As a further description of the above technical solutions:

[0015] In step b, the two connecting base side parts in the same width direction are connected and fixed by a connecting rod.

[0016] As a further description of the above technical solutions:

[0017] In step b, the telescopic rod is connected with the hoop through a spherical hinge or is fixedly connected with the hoop, and the inner diameter of the hoop is larger than the outer diameter of the drain pipe.

[0018] As a further description of the above technical solutions:

[0019] In step b, first, the support pile is fixed on the riverbed, then the U-shaped rod, the straight rod and the connecting rod are connected, so that the crossbar part of the U-shaped rod is parallel to the width direction of the working face and the length direction of the drain pipe, and the crossbar part of the U-shaped rod is located directly below the drain pipe; the hoop is arranged on the drain pipe, the lower part of the hoop is connected with the telescopic rod, the drain pipe is fixed with the drain pipe or the large-diameter steel pipe which has been fixed in the front, and then the bottom end of the telescopic rod is connected with the U-shaped rod, and the telescopic rod is adjusted to form a support for the drain pipe by the adjustable support.

[0020] As a further description of the above technical solutions:

[0021] In step c, during the working face mining process, when the hoop is difficult to rotate relative to the drain pipe, the telescopic telescopic rod is used to make the hoop not in contact or slightly in contact with the drain pipe, and at this time, the self-adaptive adjustment can be realized.

[0022] As a further description of the above technical solutions:

[0023] In step d, the plugging mode is that first, the cement slurry is injected into the riverbed fissure to fill the fissure, then the high-molecular chemical flexible material or the water-swelling water-stopping material is injected, and then the cement slurry is injected again to fill the fissure; after the riverbed fissure is sealed, the riverbed position collapse pit is artificially backfilled to the original height, and is tamped.

[0024] The beneficial effects of the present application mainly include: 1. The ground river water and soil conservation method affected by coal mining proposed by the present application does not cause water resource waste, can normally supply water for agricultural and pastoral production, and is suitable for projects with small height difference on the river.

[0025] 2. The adjustable support foot designed by the present application can effectively adapt to the surface horizontal movement and sinking law, so that it can always produce appropriate support effect on the drain pipe, and ensure the normal water flow of the river upstream and downstream.

[0026] 3. In this invention, waterproof sandbags are used during mining to prevent the impact of rainwater on the working face. The sealing of riverbed fissures is carried out after the surface subsidence and deformation have stabilized following mining. Combined with a specially designed sealing method, the sealing effect of riverbed fissures can be guaranteed.

[0027] 4. The adjustable support legs designed in this invention are made of recyclable steel structure materials, and the waterproof sandbags used can also be reused in other waterproofing projects. These materials are low in cost and recyclable, so the method for soil and water conservation of surface rivers affected by coal mining in this invention can save costs. Attached Figure Description

[0028] The accompanying drawings, which constitute a part of this invention, are used to provide a further understanding of the invention and do not constitute an undue limitation of the invention. In the drawings:

[0029] Figure 1 This is a layout plan of the soil and water conservation method according to an embodiment of the present invention;

[0030] Figure 2 This is a top view of the adjustable bracket according to an embodiment of the present invention;

[0031] Figure 3 This is a side view of the adjustable bracket according to an embodiment of the present invention;

[0032] In the diagram: Working face—1, River—2, Upstream dam—3a, Downstream dam—3b, Drainage pipe—4, Adjustable support—5, Support pile—51, Connecting base—52, U-shaped rod—53, Straight rod—54, Connecting rod—55, Telescopic rod—56, Clamp—57, Sandbag—6. Detailed Implementation

[0033] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Figure 1 As shown, the engineering situation of a mine in Inner Mongolia is as follows: At a certain depth of approximately 86m underground, there is a planned working face 1 to be mined, with a total width of 227m and a mining height of approximately 7.8m. A river 2 flows horizontally through working face 1 on the surface. The river is approximately 14m wide and its direction is basically consistent with the width of working face 1 and perpendicular to its length. The terrain in the area where river 2 is located is flat with a small drop; the drop of the section of the river above working face 1 is less than 1m. This river is of great importance to the nearby agricultural and pastoral production. It is impractical to completely drain the downstream water using the existing construction plan. Firstly, the flat surface cannot completely drain the downstream water; secondly, downstream agriculture and animal husbandry also require water. In response to this situation, our company, in conjunction with the coal mine, and drawing on existing construction methods and considering the patterns of geological fissures and surface subsidence during coal mining, has proposed an ideal solution. This solution is a method for soil and water conservation of surface rivers affected by coal mining, mainly including the following steps:

[0034] a. Pre-mining dam construction and drainage

[0035] Before the mining, an upstream dam 3a is built upstream of the river 2 outside the mining influence range of the working face 1, and a downstream dam 3b is built downstream of the river 2 outside the mining influence range of the working face 1. The mining influence range refers to the range of the surface subsidence deformation after the mining of the working face 1, and the dam should be arranged outside the subsidence deformation area to prevent the influence of mining and to be not conducive to the stability of the dam. The determination method of the mining influence range is the prior art. In this embodiment, the coal seam is buried at a depth of 86 m, and the basic rock layer is about 80 m thick. There is only a 6 m thick soil layer on the ground. The base rock movement angle is 77°, and the loose layer movement angle is 42°. It can be determined that the working face mining influence range = 80 x cot 77° + 6 x cot 42° = 25.1 m. A protection zone of about 10 m is taken. Finally, the upstream dam 3a is built 35 m upstream of the working face 1, and the downstream dam 3b is built 35 m downstream of the working face 1. The upstream dam 3a and the downstream dam 3b are about 297 m apart. The upstream dam 3a and the downstream dam 3b have the same height and are 1-2 m higher than the highest surface of the river 2, that is, 1-2 m higher than the two banks of the river. A water passage is reserved on the dam. The height center of the water passage is lower than the average water level of the river in normal years. The diameter and number of the water passage meet the water flow demand and can adapt to the normal flow of water from the upstream to the downstream. A large-diameter steel pipe is arranged in the water passage. A valve is arranged on the large-diameter steel pipe. The river section between the upstream dam 3a and the downstream dam 3b is separated from the river by closing the valve. Water in the river section between the upstream dam 3a and the downstream dam 3b is pumped into the upstream and downstream of the river 2 by a water pump.

[0036] b. Pipe laying and adjustable support setting

[0037] After the water in the river section between the upstream dam 3a and the downstream dam 3b is discharged, the riverbed silt in the river section is cleaned and the riverbed is leveled. Drainage pipes 4 are laid from the upstream dam 3a to the downstream dam 3b in sections, and the large-diameter steel pipes are connected to connect the upstream dam 3a and the downstream dam 3b. In this embodiment, three drainage pipes 4 are laid. The drainage pipes 4 are hard pipes, and preferably plastic drainage pipes, which have the advantages of light weight and low price. The diameter of the drainage pipes 4 is 40 cm, and the total length of each drainage pipe 4 is about 293 m. The length of the large-diameter steel pipe outside the dam is about 2 m. The drainage pipes 4 are arranged straight and have a laying height higher than the bottom surface of the riverbed and are flush with the large-diameter steel pipe. Adjustable supports 5 are arranged between the riverbed and the drainage pipes 4. The adjustable supports 5 can be extended and retracted to adapt to the subsidence of the riverbed caused by the mining of the working face. The adjustable supports 5 and the horizontal movement and the difference in horizontal movement of the riverbed at different positions enable the adjustable supports 5 to always support the drainage pipes 4 during the mining of the working face.

[0038] As Figures 2-3As shown, the adjustable bracket 5 includes four support piles 51, with two support piles 51 in the front and two support piles 51 in the rear (as shown). Figure 1 For example, here "front" refers to the direction where mining stops, and "back" refers to the direction where mining begins (left is upstream, right is downstream). The line connecting the two front support piles 51 is parallel to the line connecting the two rear support piles 51, and both are parallel to the width direction of the working face. A connecting base 52 is provided at the center of the upper part of each support pile 51, and the two connecting bases in the same width direction are connected and fixed by connecting rods 55. U-shaped rods 53 are provided on two connecting bases 52 of the same width direction. The two ends of the U-shaped rods 53 are rotatably connected to the two connecting bases 52 respectively. Straight rods 54 are provided on two other connecting bases 52 of the same width direction. One end of the two straight rods 54 is rotatably connected to the two connecting bases 52 respectively, and the other end is rotatably connected to the crossbar portion of the U-shaped rod 53. Two telescopic rods 56 are provided on the crossbar portion of the U-shaped rod 53. One end of the telescopic rod 56 is rotatably connected to the crossbar portion of the U-shaped rod 53, and the other end is connected to a clamp 57. The telescopic rod 56 and the clamp 57 are connected by a ball joint or fixedly connected to the clamp 57. The inner diameter of the clamp 57 is larger than the outer diameter of the drain pipe, and the clamp 57 can rotate relative to the drain pipe.

[0039] When laying the drainage pipe 4, first fix the support pile 51 and its upper connecting base 52 on the riverbed. Then connect the U-shaped rod 53, the straight rod 54, and the connecting rod 55, so that the horizontal part of the U-shaped rod 53 is parallel to the width direction of the working surface and the length direction of the drainage pipe, and that the horizontal part of the U-shaped rod 53 is directly below the drainage pipe. A clamp 57 is inserted through the drainage pipe 4, and a telescopic rod 56 is connected to the lower part of the clamp 57 to fix the drainage pipe to the previously installed and fixed drainage pipe or large-diameter steel pipe. Then connect the bottom end of the telescopic rod 56 to the U-shaped rod 53, and adjust the telescopic rod 56 so that the adjustable bracket 5 supports the drainage pipe 4.

[0040] After connecting the large-diameter steel pipes upstream and downstream of the river through drainage pipe 4, open the valve to connect the upstream and downstream of the river through drainage pipe 4.

[0041] c. Adopt a water-blocking and drainage system and adjust the adjustable support.

[0042] Before the working face is mined back to the location affecting the river, waterproof sandbags 6 are laid on both banks of the river. The waterproof sandbags 6 can prevent rainwater around the river from accumulating in the river during the rainy season and prevent water from entering the mine working face in large quantities through the cracks that are formed in the riverbed after the working face is mined. After the waterproof sandbags are laid, only the rainwater falling on the riverbed will enter the working face through the cracks in the riverbed, but this part of the rainwater is limited and can be discharged by the underground drainage pump.

[0043] When the working face is mined to the section affecting the river, if it is in the rainy season, the water around the river can be separated from the river by the waterproof sand bag 6 to prevent the water from gathering in the river and flowing into the working face from the river bed to cause water inrush accidents; meanwhile, a drainage pump is additionally arranged in the working face in the rainy season to drain the water flowing into the working face from the surface fissure;

[0044] Meanwhile, when the working face is mined to the section affecting the river, the horizontal movement law of each support pile 51 is to firstly move to the stopping position direction, and then move to the open cut direction (move away from the stopping position) until it almost recovers to the original position. Each support pile 51 also continuously sinks downward along with the horizontal movement. For the horizontal movement difference between the support piles 51, the connection mode of the connecting base 52, the U-shaped rod 53 and the straight rod 54 can be adaptively deformed, and for the change of the subsidence and the descent of the U-shaped rod 53 horizontal rod after the deformation of the connecting base 52, the U-shaped rod 53 and the straight rod 54, the telescopic rod 56 is adaptively deformed; and the adjustable support can also adapt to the offset (horizontal movement) change relative to the drainage pipe. During the working face mining process, when the clamp 57 is difficult to rotate relative to the drainage pipe 4, the telescopic rod 56 is used to make the clamp 57 not in contact or slightly in contact with the drainage pipe, and at this time, the rotation can be self-adapted.

[0045] d. Post-mining surface fissure sealing, river bed backfilling and compaction

[0046] The prior art adopts mining fissure sealing, but the mining fissure continuously changes in opening and closing with the mining of the working face, and the sealing is invalid when and after the sealing is performed due to the change of the fissure, which becomes a problem of the mining fissure sealing. Therefore, the waterproof sand bag is used in the mining to prevent the influence of the rain season water on the working face production, and the river bed fissure sealing is performed after the surface subsidence and deformation are stable, so that the sealing effect of the river bed fissure can be ensured. The sealing mode is to firstly inject cement slurry into the river bed fissure to fill the fissure, then inject high polymer chemical flexible material or water-swelling water-stop material, and then inject cement slurry into the fissure again. After the river bed fissure is sealed, the local soil is used to artificially backfill the river bed position subsidence pit, the river bed is backfilled to the original height, and is compacted.

[0047] The valve is closed, the adjustable support 5 and the drainage pipe are recovered, the valve is opened after the recovery is completed, and the river returns to normal.

[0048] The present application is not limited to the above best mode of implementation, and anyone can derive other various forms of products under the inspiration of the present application, but regardless of any changes in shape or structure, any technical solution with the same or similar to the present application falls within the protection scope of the present application.

Claims

1. A method of water and soil conservation of a surface river affected by coal mining, characterized by, The method comprises the following steps: a. Building a dam to drain water before mining: building an upstream dam upstream of the river outside the working face mining influence range, and building a downstream dam downstream of the river; reserving a water passage on the dam, setting a large-diameter steel pipe in the water passage, setting a valve on the large-diameter steel pipe, closing the valve, and draining water in the river section between the upstream dam and the downstream dam; b. Laying pipes and setting adjustable supports: laying drainage pipes section by section, connecting the river upstream and downstream through the large-diameter steel pipe and the drainage pipe; the drainage pipe is made of hard pipe and is arranged flat, and the laying height is higher than the riverbed bottom surface and is flush with the large-diameter steel pipe; adjustable supports are arranged between the riverbed and the drainage pipe, the adjustable supports comprise four support piles, two support piles in front and two support piles in back, the connecting line of the two support piles in front is parallel to the connecting line of the two support piles in back, and both are parallel to the width direction of the working face; a connecting base is arranged at the upper center of each support pile; a U-shaped rod is arranged on two connecting bases in the same width direction, the two ends of the U-shaped rod are rotatably connected with the two connecting bases, respectively; two straight rods are arranged on two connecting bases in the same width direction, respectively, one end of the two straight rods is rotatably connected with the two connecting bases, respectively, and the other end is rotatably connected with the crossbar part of the U-shaped rod; two telescopic rods are arranged on the crossbar part of the U-shaped rod, one end of the telescopic rod is rotatably connected with the crossbar part of the U-shaped rod, and the other end is connected with a clamp; the telescopic rod and the clamp are connected through a spherical hinge; the clamp can rotate circumferentially relative to the drainage pipe; after connecting the large-diameter steel pipes upstream and downstream of the river through the drainage pipe, the valve is opened; c. Water isolation, water drainage and adjustable support adjustment during mining: laying waterproof sandbags on both banks of the river before the working face is mined to the position affecting the river; when the working face is mined to the section affecting the river, the water around the river is isolated from the river through the waterproof sandbags; at the same time, a drainage pump is additionally arranged in the working face to drain water flowing into the working face from the ground fissure; the adjustable support changes position due to mining, and the telescopic telescopic rod is adaptively adjusted to support the drainage pipe; d. Ground fissure sealing, riverbed backfilling and compaction after mining; the valve is closed, the adjustable support and the drainage pipe are recovered, the valve is opened after the recovery is completed, and the river returns to normal.

2. The water and soil conservation method according to claim 1, characterized by, In step a, the upstream dam and the downstream dam are both higher than the highest surface of the river by a certain height; the height center of the water passage is lower than the average water level of the river in normal years, and the diameter and the number of the water passage meet the water flow demand.

3. The water and soil conservation method according to claim 1, characterized by, In step b, the two connecting bases in the same width direction are fixed through connecting rods on the sides.

4. The water and soil conservation method according to claim 3, characterized by, In step b, the telescopic rod and the clamp are connected through a spherical hinge or fixedly connected with the clamp, and the inner diameter of the clamp is greater than the outer diameter of the drainage pipe.

5. The water and soil conservation method according to claim 4, characterized by, In step b, first fix the support pile on the riverbed, then connect the U-shaped rod, straight rod and connecting rod, make the crossbar part of the U-shaped rod parallel to the working face width direction and the length direction of the drain pipe, and make the crossbar part of the U-shaped rod directly below the drain pipe; the clamp is provided on the drain pipe, the lower part of the clamp is connected with the telescopic rod, the drain pipe is fixed with the drain pipe or large diameter steel pipe which has been installed and fixed in front, then the bottom end of the telescopic rod is connected with the U-shaped rod, and the telescopic rod is adjusted to make the adjustable support support the drain pipe.

6. The water and soil conservation method according to claim 5, characterized by In the process of working face mining, when the clamp is difficult to rotate relative to the drain pipe, the telescopic rod is used to make the clamp not in contact or slightly in contact with the drain pipe, at this time, the self-adaptive adjustment can be made.

7. The water and soil conservation method according to any one of claims 1 to 6, characterized by, In step d, the plugging method is first filling the fissure with cement slurry, then injecting high molecular chemical flexible material or water-swelling water-stop material, and then filling the fissure with cement slurry again; after the fissure of the riverbed is plugged, the riverbed position collapse pit is artificially backfilled, the riverbed is backfilled to the original height, and is tamped.

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