Downward mining water control method for working face near aquifer

Abstract

The invention provides a near-aquifer working face descending mining water control method. The water control method comprises the following steps that 1, the design number of adopted working faces and the working face replacement sequence are determined; 2, a water retaining curtain is constructed corresponding to the working face affected by the aquifer; 3, water pumping drill holes are constructed in the water retaining curtain to the aquifer, water pumping is conducted, and meanwhile grouting is conducted in the aquifer; 4, stoping is conducted upwards from the first working face at the deepest position of the coal seam, after stoping is conducted on the first working face, water inflow detection is conducted on the next working face, and water drainage work is conducted in time; 5, before the last working face is stoped, water inflow detection is conducted on the last working face and the adjacent roadways, and water drainage work is conducted; and if it is detected that the water inflow is large, grouting treatment is supplemented within the range of the water retaining curtain. According to the water control method, the construction cost is reduced, the construction efficiency is improved, and the ecological environment is protected while the effect that no water is stored in the water retaining curtain is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of safe mining of coal mines, and specifically relates to a water control method for downward mining near an aquifer working face. Background Art

[0002] Water inrush refers to the phenomenon that a large amount of groundwater suddenly rushes into the mine tunnel. Mine water inrush is one of the most threatening disasters in the coal mine production process, with heavy casualties and economic losses, ranking first among the three major coal mine accidents. When the bedrock between the loose aquifer and the coal seam is thin, making the distance between the loose aquifer and the coal seam close, water inrush accidents are very likely to occur during the mining process.

[0003] In order to ensure the safety of coal mining, the traditional practice is to leave a coal pillar at a certain distance between the coal seam and the loose aquifer, and to perform grouting reinforcement on the top of the coal seam. The above traditional practice not only causes the loss of coal resources, but also when grouting reinforcement is performed on the top of the coal seam, the slurry escapes everywhere, causing a large amount of slurry to be wasted, and the effectiveness of grouting reinforcement cannot be guaranteed, thereby increasing the construction cost.

[0004] Therefore, it is necessary to provide an improved technical solution to address the above-mentioned deficiencies in the prior art. Invention content

[0005] The purpose of the invention is to provide a method for controlling water during downward exploitation near an aquifer working face, so as to at least solve the above-mentioned problems existing in the prior art.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for controlling water during downward mining near an aquifer working face, the method comprising the following steps:

[0008] Step 1: Determine the number of working faces to be designed and the order of succession of working faces according to the distance relationship between the upper boundary of the coal seam and the aquifer and impermeable layer;

[0009] Step 2, constructing a water retaining curtain on the working surface affected by the aquifer, wherein the water retaining curtain is a pile-connected wall structure;

[0010] The water retaining curtain extends from the ground to the water-proof layer, and the water retaining curtain covers the working face affected by the aquifer and the tunnel near the working face in the vertical projection direction;

[0011] Step 3, drilling a pumping hole in the water retaining curtain to the aquifer and pumping water, and injecting grout into the aquifer at the same time, until there is no water in the water retaining curtain and the aquifer is filled with grouting liquid;

[0012] Step 4, mining is carried out upward from the first working face at the deepest part of the coal seam. After the mining of the first working face is completed, the water inflow is detected for the next working face and the roadway near the working face, and water is drained in time until the last working face closest to the aquifer is mined;

[0013] Step 5. Before mining the last working face, test the water gushing volume of the last working face and nearby tunnels, and drain the water. If the water gushing volume is large, carry out additional grouting treatment within the water retaining curtain range until the water gushing volume meets the standard, and then carry out mining operations on the last working face.

[0014] As described above, in the method for controlling water during downward exploitation at a working face near an aquifer, preferably, the water retaining curtain is provided with a guide wall facing the direction of water flow in the aquifer, and the guide wall has an inclination angle with the direction of water flow in the aquifer.

[0015] In the method for controlling water during downward exploitation at a working face near an aquifer as described above, preferably, the guide wall is a herringbone wall, and the tip of the herringbone wall faces the water flow direction of the aquifer.

[0016] As described above, in the method for controlling water during downward exploitation at a working face near an aquifer, preferably, in the vertical projection direction, the herringbone wall is located at the front side of the front end of the working face affected by the aquifer.

[0017] As described above, in the method for controlling water during downward exploitation at a working face near an aquifer, preferably, the water retaining curtain further comprises two transverse walls, and the two transverse walls are respectively connected to both sides of the herringbone wall.

[0018] In the method for downward exploitation and water control near the aquifer working face as described above, preferably, the spacing between the two transverse walls is greater than the width of the working face affected by the aquifer, and in the vertical projection direction, the two transverse walls are located on the outside of the left and right sides of the working face affected by the aquifer.

[0019] As described above, in the method for controlling water during downward exploitation at a working face near an aquifer, preferably, the water retaining curtain further comprises a longitudinal wall connected to ends of the two transverse walls away from the herringbone wall.

[0020] As described above, in the method for controlling water during downward exploitation at a working face near an aquifer, preferably, in the vertical projection direction, the longitudinal wall is located at the rear side of the rear end of the working face affected by the aquifer.

[0021] As described above, in the method for downward exploitation and water control near the aquifer working face, preferably, in step 3, the pumping borehole extends into the middle and upper part of the aquifer, a steel casing is provided inside the pumping borehole, and a filter is provided at the bottom of the steel casing.

[0022] As described above, in the method for controlling water during downward exploitation at a working face near an aquifer, preferably, in step 3, grouting anchor rods are provided to grout the aquifer, and the bottom ends of the grouting anchor rods extend into the upper part of the aquiclude.

[0023] Beneficial effects:

[0024] In this water control method, the water retaining curtain not only plays a role in isolating water and reducing the amount of water pumped, but also plays a role in preventing the grouting liquid from escaping, further reducing the amount of grouting. While pumping water, grouting is carried out, and the grouting liquid sinks to the bottom of the aquifer in the water retaining curtain, raising the water level in the water retaining curtain, making it easier to pump water. Moreover, groundwater resources are protected, and the local ecological environment is protected. The water retaining curtain, grouting operation and pumping operation work together to achieve the effect of no water accumulation in the water retaining curtain, while also greatly reducing construction costs, improving construction efficiency, and protecting the ecological environment.

[0025] The water flow in the aquifer flows to both sides of the herringbone wall through the diversion effect of the herringbone wall, avoiding the water flow directly vertically scouring the herringbone wall, ensuring that the herringbone wall is subjected to the smallest possible impact force of the water flow, ensuring that the herringbone wall can always effectively play its diversion role and preventing water from seeping into the interior of the water retaining curtain wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The drawings constituting part of the present application are used to provide a further understanding of the invention. The exemplary embodiments and descriptions of the invention are used to explain the invention and do not constitute an improper limitation on the invention. Among them:

[0027] Figure 1 A schematic cross-sectional view of a method for controlling water in a downward mining operation near an aquifer working face according to an embodiment of the present invention;

[0028] Figure 2 A top view of a water retaining curtain in accordance with one embodiment of the present invention.

[0029] In the figure: 1. Water retaining curtain; 11. Herringbone wall; 12. Transverse wall; 13. Longitudinal wall; 2. Pumping borehole; 3. Grouting anchor rod; 4. Working surface affected by aquifer. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0031] In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention. The terms "connected" and "connected" used in the present invention should be understood in a broad sense. For example, they can be fixedly connected or detachably connected; they can be directly connected or indirectly connected through intermediate components. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0032] The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict.

[0033] According to the specific embodiments of the present invention, Figure 1-2 As shown, the present invention provides a method for controlling water during downward mining near an aquifer working face, the method comprising the following steps:

[0034] Step 1: Determine the number of working faces to be designed and the order of succession of working faces based on the distance relationship between the upper boundary of the coal seam and the aquifer and impermeable layer.

[0035] Step 2, construct a water retaining curtain 1 corresponding to the working face affected by the aquifer, and the water retaining curtain 1 is a pile-connected wall structure; in this embodiment, the pile-connected wall structure is formed by interlocking multiple pile foundations, wherein the pile foundation can be selected from bored cast-in-place piles, cement mixing piles, rotary piles and other structures, and the appropriate pile foundation type is selected according to the specific geological conditions. The pile-connected wall is formed by interlocking multiple pile foundations, and the disturbance range is small during the construction process, and the impact on the underground aquifer and coal seam structure is also small.

[0036] The water retaining curtain 1 extends from the ground to the aquiclude, and in the vertical projection direction, the water retaining curtain 1 covers the working face affected by the aquifer and the tunnels near the working face.

[0037] Step 3, drilling a pumping hole 2 in the water retaining curtain 1 to the aquifer and pumping water, and injecting grout into the aquifer at the same time, until there is no water in the water retaining curtain 1 and the aquifer is filled with grouting liquid.

[0038] Step 4, mining is carried out from the first working face at the deepest part of the coal seam upwards. After the mining of the first working face is completed, the water inflow is detected on the next working face and the tunnels near the working face, and water drainage is carried out in time until the last working face closest to the aquifer is mined.

[0039] Step 5, before mining the last working face, detect the water inflow of the last working face and nearby tunnels, and carry out water drainage work; if the detected water inflow is large, carry out additional grouting treatment within the range of the water retaining curtain 1, and then carry out mining operations on the last working face after the detected water inflow meets the standard.

[0040] In this water control method, since the last working face is closest to the aquifer, and the collapse zone and water-conducting fracture zone of the last working face are very close to the aquifer, the aquifer has a greater impact on the last working face.

[0041] By constructing a water-retaining curtain 1 from the ground to the aquiclude, and the water-retaining curtain 1 completely covers the working face affected by the aquifer in the vertical projection direction, the aquifer that has a greater impact on the working face is first isolated by the water-retaining curtain 1, so that the water in the water-retaining curtain 1 and the water outside the water-retaining curtain 1 do not affect each other; then, a hole is drilled in the water-retaining curtain 1, and a pumping pipe is lowered into the drilled hole to carry out pumping operations, and grouting operations are carried out in the water-retaining curtain 1 while pumping water. Due to the limitation of the water-retaining curtain 1, most of the grouting liquid will be retained in the water-retaining curtain 1 instead of escaping everywhere, and the grouting can also raise the height of the water in the water-retaining curtain 1, thereby making it easier to pump out the water in the water-retaining curtain 1, so that there is no water in the water-retaining curtain 1; at the same time, after each working face is mined, the water gushing volume is checked and treated, which plays a double insurance role and fundamentally guarantees the safety of the working face mining.

[0042] Among them, the water retaining curtain 1 not only plays a water-isolating role, which can reduce the amount of pumping; it also plays a role in preventing the grouting liquid from escaping, which can further reduce the amount of grouting; while grouting is carried out while pumping, the grouting liquid sinks to the bottom of the aquifer in the water retaining curtain 1, thereby raising the water surface height in the water retaining curtain 1, which is more convenient for pumping operations; and only pumping operations are carried out in the water retaining curtain 1, and excessive pumping of water from the aquifer outside the water retaining curtain 1 will not be carried out, so that groundwater resources are protected, and thus the local ecological environment is also protected; in summary, the water retaining curtain 1, grouting operations and pumping operations work together to achieve the effect of no water storage in the water retaining curtain 1, while also greatly reducing construction costs, improving construction efficiency, and protecting the ecological environment.

[0043] The water retaining curtain 1 is provided with a guide wall facing the water flow direction of the aquifer, and the guide wall has an inclined angle with the water flow direction of the aquifer. In one embodiment of the present application, a guide wall with an inclined angle with the water flow direction is provided in front of the water retaining curtain 1, thereby preventing the water flow of the aquifer from directly impacting the water retaining curtain 1, and ensuring the safety and effectiveness of the water retaining curtain 1.

[0044] The diversion wall is a herringbone wall 11, and the tip of the herringbone wall 11 faces the water flow direction of the aquifer. In one embodiment of the present application, the water flow of the aquifer flows to both sides of the herringbone wall 11 through the diversion effect of the herringbone wall 11, thereby preventing the water flow from directly and vertically scouring the herringbone wall 11, ensuring that the herringbone wall 11 is subjected to the smallest possible impact force of the water flow, thereby ensuring that the herringbone wall 11 can always effectively play its diversion role and preventing the water flow from infiltrating into the interior of the water retaining curtain wall.

[0045] In the vertical projection direction, the herringbone wall 11 is located in front of the front end of the working face 4 affected by the aquifer. In one embodiment of the present application, the herringbone wall 11 is located in front of the front end of the working face 4 affected by the aquifer in the vertical projection direction, so that the herringbone wall 11 can cover a larger range in front of the aquifer affecting the working face.

[0046] The water retaining curtain 1 further includes two transverse walls 12 , which are respectively connected to two sides of the herringbone wall 11 .

[0047] The distance between the two transverse walls 12 is greater than the width of the working surface 4 affected by the aquifer, and in the vertical projection direction, the two transverse walls 12 are located outside the left and right sides of the working surface 4 affected by the aquifer.

[0048] In one embodiment of the present application, two transverse walls 12 are connected on both sides of the herringbone wall 11. In the vertical projection direction, the two transverse walls 12 are arranged on the periphery of the working surface, so that the two transverse walls 12 can cover a larger area on both sides of the aquifer that affects the working surface, thereby facilitating subsequent aquifer management operations in the water retaining curtain 1.

[0049] The water retaining curtain 1 also includes a longitudinal wall 13, which is connected to the ends of the two transverse walls 12 away from the herringbone wall 11. In one embodiment of the present application, the herringbone wall 11, the two transverse walls 12 and the longitudinal wall 13 form a completely closed curtain, and the closed water retaining curtain 1 completely encloses the aquifer that affects the working surface, and the lower part of the closed water retaining curtain 1 extends to the waterproof layer, so that the water bodies inside and outside the closed water retaining curtain 1 do not affect each other, thereby making it easier to pump water inside the closed water retaining curtain 1.

[0050] In the vertical projection direction, the longitudinal wall 13 is located at the rear side of the rear end of the working surface 4 affected by the aquifer. In one embodiment of the present application, the longitudinal wall 13 is located at the outer side of the working surface 4 affected by the aquifer in the vertical projection direction, so that the longitudinal wall 13 can cover a larger range of the rear side of the aquifer affecting the working surface, thereby facilitating the water retaining curtain 1 to better seal the aquifer affecting the working surface.

[0051] In step 3, the pumping borehole 2 extends into the middle and upper part of the aquifer, a steel casing is provided inside the pumping borehole 2, and a filter is provided at the bottom of the steel casing. In one embodiment of the present application, a plurality of pumping boreholes 2 are provided, and the plurality of pumping boreholes 2 are evenly distributed within the water retaining curtain 1; the pumping borehole 2 extends into the middle and upper part of the aquifer, rather than directly into the lower part of the aquifer, because during the pumping process, grouting is performed into the aquifer, and the grouting liquid will gradually raise the water level in the aquifer, so that the water level in the aquifer is always maintained in the middle and upper position, so that the pumping borehole 2 is convenient for pumping out the water in the aquifer in the water retaining curtain 1, and thus the aquifer can be prevented from affecting the recovery work of the last working face as much as possible.

[0052] The steel casing is arranged in the water-pumping borehole 2 to prevent the water-pumping borehole 2 from collapsing, and the filter screen can filter sand and gravel well, thereby preventing the sand and gravel from affecting the water-pumping operation.

[0053] In step 3, a grouting anchor rod 3 is provided to grout the aquifer, and the bottom end of the grouting anchor rod 3 extends into the upper part of the aquifer. In one embodiment of the present application, a plurality of grouting anchor rods 3 are provided, and the plurality of grouting anchor rods 3 are evenly distributed within the water retaining curtain 1, and the plurality of grouting anchor rods 3 and the plurality of pumping boreholes 2 are arranged in an interlaced manner; the bottom end of the grouting anchor rod 3 extends into the aquifer, so that the grouting anchor rod 3 can not only grout the aquifer, but also grout the aquifer for reinforcement.

[0054] In this embodiment, the water retaining curtain 1 extends to the bottom of the aquifer. When grouting is performed, due to the limiting effect of the water retaining curtain 1, most of the grouting liquid will be retained in the water retaining curtain 1. The grouting liquid will first diffuse in the lowest aquifer to reinforce the aquifer. At this time, the water retaining curtain 1 and the bottom aquifer complete the wrapping of the aquifer that affects the working surface. With the continuous injection of the grouting liquid, the grouting liquid gradually accumulates at the bottom of the aquifer, thereby raising the water level in the aquifer, making it easier to pump water from the water retaining curtain 1. After the pumping and grouting operations are completed, there is basically no water in the aquifer in the water retaining curtain 1, thereby fundamentally solving the water inrush effect of the aquifer on the last working surface, and ensuring the safety of the working surface recovery operation as much as possible.

[0055] It should be understood that the above description is merely exemplary and the embodiments of the present application do not limit this.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention are within the scope of protection of the pending claims of the present invention.

Claims

1. A method for controlling water during downward mining near an aquifer working face, characterized in that: The water control method comprises the following steps: Step 1: Determine the number of working faces to be designed and the order of succession of working faces according to the distance relationship between the upper boundary of the coal seam and the aquifer and impermeable layer; Step 2, constructing a water retaining curtain on the working surface affected by the aquifer, wherein the water retaining curtain is a pile-connected wall structure; The water retaining curtain extends from the ground to the water-proof layer, and the water retaining curtain covers the working face affected by the aquifer and the tunnel near the working face in the vertical projection direction; Step 3, drilling a pumping hole in the water retaining curtain to the aquifer and pumping water, and injecting grout into the aquifer at the same time, until there is no water in the water retaining curtain and the aquifer is filled with grouting liquid; Step 4, mining is carried out upward from the first working face at the deepest part of the coal seam. After the mining of the first working face is completed, the water inflow is detected for the next working face and the roadway near the working face, and water is drained in time until the last working face closest to the aquifer is mined; Step 5. Before mining the last working face, test the water gushing volume of the last working face and nearby tunnels, and drain the water. If the water gushing volume is large, carry out additional grouting treatment within the water retaining curtain range until the water gushing volume meets the standard, and then carry out mining operations on the last working face.

2. The method for controlling water during downward mining near the aquifer working face according to claim 1, characterized in that: The water retaining curtain is provided with a guide wall facing the water flow direction of the aquifer, and the guide wall has an inclined angle with the water flow direction of the aquifer.

3. The method for controlling water during downward mining near the aquifer working face according to claim 2, characterized in that: The diversion wall is a herringbone wall, and the tip of the herringbone wall faces the water flow direction of the aquifer.

4. The method for controlling water during downward mining near the aquifer working face according to claim 3 is characterized in that: In the vertical projection direction, the herringbone wall is located at the front side of the front end of the working face affected by the aquifer.

5. The method for controlling water during downward mining near the aquifer working face according to claim 3 is characterized in that: The water retaining curtain also includes two transverse walls, which are respectively connected to both sides of the herringbone wall.

6. The method for controlling water during downward mining near the aquifer working face according to claim 5, characterized in that: The distance between the two transverse walls is greater than the width of the working surface affected by the aquifer, and in the vertical projection direction, the two transverse walls are located outside the left and right sides of the working surface affected by the aquifer.

7. The method for controlling water during downward mining near the aquifer working face according to claim 5, characterized in that: The water retaining curtain further comprises a longitudinal wall connected to ends of the two transverse walls away from the herringbone wall.

8. The method for controlling water during downward mining near the aquifer working face according to claim 7, characterized in that: In the vertical projection direction, the longitudinal wall is located at the rear side of the rear end of the working face affected by the aquifer.

9. The method for controlling water during downward mining near an aquifer working face according to any one of claims 1 to 8, characterized in that: In step 3, the water-pumping borehole extends into the middle and upper part of the aquifer, a steel casing is arranged inside the water-pumping borehole, and a filter is arranged at the bottom of the steel casing.

10. The method for controlling water during downward mining near an aquifer working face according to any one of claims 1 to 8, characterized in that: In step 3, grouting anchor rods are arranged to perform grouting on the aquifer, and the bottom ends of the grouting anchor rods extend into the upper part of the aquiclude.

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