A method for rapid assessment and treatment of water diversion safety in overburden rock under mining at working face

Abstract

The invention provides a method for quickly evaluating and treating the water diversion safety of the overburden in the working face mining. In the treatment method, before the working face is mined, a waterproof curtain is constructed along the boundary of the surface subsidence range. The waterproof curtain extends from the surface to the bottom waterproof layer, so that in the vertical projection direction, the bottom aquifer within the surface subsidence range is completely enclosed by the waterproof curtain, so that the water inside and outside the waterproof curtain does not interfere with each other, thereby reducing the amount of water that affects the mining of the working face. At the same time, multiple water level and crack monitoring components are arranged. During the mining process of the working face 1, the water level in the waterproof curtain and the cracks caused by the sinking of the bottom waterproof layer are monitored in real time through the water level and crack monitoring components, and corresponding treatment measures are taken according to the corresponding situation; the waterproof curtain, grouting operation and pumping operation work together to achieve the effect of no water storage in the waterproof curtain, while also greatly reducing the construction cost, improving the construction efficiency, and protecting the ecological environment.

Description

Technical Field

[0001] The invention belongs to the technical field of safe mining of coal mines, and in particular relates to a method for quickly evaluating and treating water diversion safety of overburden rocks under mining at a working face. Background Art

[0002] There are many coal mining sites near aquifers in my country, and frequent accidents of water-rock coupling frame crushing and water inrush occur. Mine water inrush refers to the phenomenon that a large amount of groundwater suddenly rushes into the shaft. 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.

[0003] In order to ensure the safety of coal mining, the traditional practice is to drain water in time and reinforce the top of the coal seam with grouting. When the aquifer is the main water source for production and life in the area, excessive drainage will cause the loss of groundwater resources and the drop of water level, seriously affecting the balance of the local ecological environment and causing the deterioration of the ecological environment; and when grouting is performed on the top of the coal seam, the slurry escapes everywhere, causing a large amount of slurry waste, and the effectiveness of grouting reinforcement cannot be guaranteed, 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 quickly evaluating and treating water diversion safety of overburden under mining at a 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 quickly evaluating and treating water diversion safety of overburden under mining at a working face, the method comprising the following steps:

[0008] Step 1: Determine the scope of surface subsidence, water-conducting fracture zone and collapse zone after mining of the working face according to the spatial position relationship between the working face and the aquifer, the physical and mechanical parameters of the coal seam where the working face is located and the top and bottom strata of the coal seam, and the hydrological data of the aquifer;

[0009] From top to bottom, the rock formations include the upper loose layer, the middle aquifer, the middle aquiclude, the bottom aquifer, the bottom aquiclude and the coal seam where the working face is located;

[0010] Step 2: within the vertical projection range of the working face, a plurality of monitoring holes are drilled from the ground, and a water level and crack monitoring component is arranged in each monitoring hole, wherein the water level and crack monitoring component is used to monitor the water level change of the bottom aquifer and the damage of the overburden rock;

[0011] Step 3, constructing a waterproof curtain along the boundary of the surface subsidence range, wherein the waterproof curtain extends from the surface to the bottom waterproof layer;

[0012] Step 4: The working face performs mining operations, and monitors the water level changes of the bottom aquifer and the crack damage of the overburden on the working face in real time through the water level and crack monitoring components;

[0013] Step 5: When the water level change or the fracture damage range exceeds the first warning value, underground water drainage operation is carried out, and recovery is continued after the underground water inflow reaches a safe value;

[0014] When the water level change or the scope of fracture damage exceeds the second warning value, conduct a combined operation of drainage from the well and underground drainage, and continue mining after the underground water inflow reaches a safe value;

[0015] When the water level change or the scope of fracture damage exceeds the third warning value, the water is drained from the well and underground at the same time, grouting holes are drilled from the ground, and the bottom aquifer and the bottom impermeable layer are grouted. After the water in the bottom aquifer within the impermeable curtain is pumped out and filled with grouting liquid and the grouting liquid solidifies, the recovery will continue.

[0016] As described above, the method for rapid assessment and treatment of water conduction safety in overburden rock under mining at a working face is preferably provided with water level and crack monitoring components in the middle and on both sides of the working face.

[0017] As described above, the method for rapid assessment and treatment of water conduction safety in overburden strata under working face mining is preferably such that the water level and fracture monitoring component penetrates deep into the working face collapse zone.

[0018] As described above, the method for rapid assessment and treatment of water conduction safety in overburden rock under working face mining, preferably, the water level and fissure monitoring assembly includes a drill rod, multiple water level sensors and multiple displacement sensors, the multiple water level sensors and multiple displacement sensors are arranged in parallel on the drill rod, and the drill rod is inserted into the monitoring hole.

[0019] As described above, in the method for rapid assessment and treatment of water diversion safety in overburden rock under working face mining, preferably, the water-blocking curtain is a pile-connected wall, and the pile-connected wall includes a plurality of pile foundation units, and adjacent pile foundation units are interlocked and connected with each other.

[0020] As described above, the method for rapid assessment and treatment of water diversion safety in overburden rock under working face mining, preferably, the pile foundation unit is a bored cast-in-place pile, a cement mixing pile, or a rotary drilling pile.

[0021] As described above, the method for rapid assessment and treatment of water conduction safety in the overburden rock under the working face mining is preferably, when conducting water drainage operations on the well, a pumping borehole is drilled within the water-conducting fracture zone to the bottom aquifer, and the water drainage operations on the well are carried out using the pumping borehole.

[0022] As described above, in the method for rapid assessment and treatment of water conduction safety in the overburden rock under working face mining, preferably, before conducting water drainage operations in the well, at least one isolation pile is first constructed within the water-conducting fracture zone, the isolation pile extending from the ground through the middle aquifer to the middle aquifer, and then a pumping hole is drilled in the middle of the isolation pile to the middle and upper part of the bottom aquifer.

[0023] As described above, the method for rapid assessment and treatment of water conduction safety in overburden rock under working face mining is preferably performed by drilling the grouting holes to the upper part of the bottom waterproof layer, and inserting grouting anchor rods into the grouting holes to carry out grouting operations.

[0024] As described above, in the method for rapid assessment and treatment of water diversion safety in overburden rock under working face mining, preferably, the bottom of the water-blocking curtain is lower than the bottom of the grouting anchor rod.

[0025] Beneficial effects:

[0026] In this treatment method, before the working face is mined, a waterproof curtain is constructed along the boundary of the surface subsidence range. The waterproof curtain extends from the surface to the bottom waterproof layer, so that in the vertical projection direction, the bottom aquifer within the surface subsidence range is completely enclosed by the waterproof curtain, so that the water inside and outside the waterproof curtain does not interfere with each other, thereby reducing the amount of water that affects the working face recovery. The waterproof curtain, grouting operation and pumping operation work together to achieve the effect of no water in the waterproof curtain, while also greatly reducing construction costs, improving construction efficiency, and protecting the ecological environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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:

[0028] Figure 1 A cross-sectional view of a water-blocking curtain arrangement for creating an embodiment of the present invention;

[0029] Figure 2 A top view of a water blocking curtain arrangement that creates an embodiment of the present invention.

[0030] In the figure: 1. Working face; 2. Water-proof curtain; 3. Grouting anchor rod; 4. Isolation pile; 5. Pumping borehole; 6. Water level and crack monitoring component. DETAILED DESCRIPTION

[0031] 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. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0032] 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.

[0033] 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.

[0034] According to the specific embodiments of the present invention, Figure 1-2 As shown, the present invention provides a method for quickly evaluating the safety of water diversion in overburden under mining at a working face, and the method comprises the following steps:

[0035] Step 1, according to the spatial position relationship between the working face 1 and the aquifer, the physical and mechanical parameters of the coal seam where the working face 1 is located and the top and bottom strata of the coal seam, and the hydrological data of the aquifer, determine the surface subsidence range, water-conducting fracture zone range and collapse zone range after the working face 1 is mined;

[0036] From top to bottom, the rock strata include an upper loose layer, a middle aquifer, a middle aquiclude, a bottom aquifer, a bottom aquiclude and the coal seam where the working face 1 is located; in the present embodiment, according to the previous geological exploration and the hydrological data of the aquifer, it is determined that the water-conducting fracture zone of the working face 1 is set close to the bottom of the bottom aquifer, which means that during the mining process of the working face 1, the gradually generated water-conducting fracture zone may be connected to the bottom aquifer, thereby causing a water inrush accident. Therefore, it is necessary to monitor the water gushing situation of the working face 1 in real time during the mining process of the working face 1 and handle the situation accordingly.

[0037] Step 2: within the vertical projection range of the working face 1, a plurality of monitoring holes are drilled from the ground, and a water level and crack monitoring assembly 6 is arranged in each monitoring hole, the water level and crack monitoring assembly 6 is used to monitor the water level change of the bottom aquifer and the damage of the overburden rock;

[0038] Step 3, constructing a waterproof curtain 2 along the boundary of the surface subsidence range, wherein the waterproof curtain 2 extends from the surface to the bottom waterproof layer;

[0039] Step 4, the working face 1 performs mining operations, and monitors the water level change of the bottom aquifer and the crack damage of the overburden on the working face 1 in real time through the water level and crack monitoring component 6;

[0040] Step 5: When the water level change or the fracture damage range exceeds the first warning value, underground water drainage operation is carried out, and recovery is continued after the underground water inflow reaches a safe value;

[0041] When the water level change or the scope of fracture damage exceeds the second warning value, conduct a combined operation of drainage from the well and underground drainage, and continue mining after the underground water inflow reaches a safe value;

[0042] When the water level change or the scope of fracture damage exceeds the third warning value, while the combined operation of above-ground drainage and underground drainage is carried out, grouting drilling is carried out from the ground, and grouting is carried out on the bottom aquifer and the bottom impermeable layer. After the water in the bottom aquifer within the impermeable curtain 2 is pumped out and filled with grouting liquid and the grouting liquid solidifies, recovery is continued.

[0043] In this treatment method, before the working face 1 is mined, a waterproof curtain 2 is constructed along the boundary of the surface subsidence range. The waterproof curtain 2 extends from the surface to the bottom waterproof layer. Thus, in the vertical projection direction, the bottom aquifer within the surface subsidence range is completely enclosed by the waterproof curtain 2, so that the water inside and outside the waterproof curtain 2 do not interfere with each other, thereby reducing the amount of water affecting the mining of the working face 1.

[0044] At the same time, multiple water level and crack monitoring components 6 are arranged. During the mining process of the working face 1, the water level in the waterproof curtain 2 and the cracks caused by the sinking of the bottom waterproof layer are monitored in real time through the water level and crack monitoring components 6; and three-level warning values ​​are set:

[0045] The first warning value represents a slight drop in the water level of the bottom aquifer and / or a slight sinking of the bottom impermeable layer, resulting in small-scale cracks. At this time, direct underground drainage operations are carried out to reduce the water inflow in working face 1 so that the underground water inflow reaches a safe value, and the recovery operation is continued on the basis that the first warning value does not further expand.

[0046] The second warning value represents a moderate drop in the water level of the bottom aquifer and / or a moderate sinking of the bottom impermeable layer, resulting in cracks within a certain range. At this time, underground drainage operations are carried out in combination with surface drainage operations to reduce the amount of water in the bottom aquifer within the impermeable curtain 2, so as to further reduce the amount of water gushing from the working face 1, so that the underground water gushing reaches a safe value, and the recovery operation continues on the basis that the second warning value does not expand further.

[0047] The third warning value represents that the water level of the bottom aquifer has dropped significantly, and / or the bottom aquitard has sunk significantly, resulting in larger cracks. At this time, a larger range of detachment is generated between the bottom aquitard and the bottom aquifer, and a certain amount of water is accumulated in the detachment, which has a greater impact on the safe production of working face 1. At this time, while the above-ground drainage and underground drainage operations are carried out together, trial holes are drilled from the ground to the bottom aquifer and the bottom aquitard, and grouting is carried out to reinforce the bottom aquifer and the bottom aquitard; so as to achieve the effect of complete extraction within the waterproof curtain 2, and the cracks caused by the sinking of the bottom aquitard are completely blocked by the grouting liquid, ensuring that the mining of working face 1 is no longer affected by the bottom aquifer and water gushing occurs, thereby ensuring the safety of mining of working face 1 to the greatest extent.

[0048] Among them, the waterproof curtain 2 not only plays a waterproof 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 pumping, grouting is carried out, and the grouting liquid sinks to the bottom of the bottom aquifer inside the waterproof curtain 2, raising the water level inside the waterproof curtain 2, thereby making it easier to pump water; the grouting liquid first fills the gaps caused by the sinking of the bottom waterproof layer and the detachment between the bottom waterproof layer and the bottom aquifer, and then the grouting gradually fills the bottom aquifer, so that the bottom aquifer and the bottom aquifer are grouting reinforced; and only pumping operations are carried out inside the waterproof curtain 2, and excessive pumping of water from the bottom aquifer outside the waterproof curtain 2 will not be carried out, so that groundwater resources are protected, and thus the local ecological environment is also protected; in summary, the waterproof curtain 2, grouting operations and pumping operations work together to achieve the effect of no water storage in the waterproof curtain 2, while also greatly reducing construction costs, improving construction efficiency, and protecting the ecological environment.

[0049] Water level and crack monitoring components 6 are arranged in the middle and on both sides of the working surface 1. In one embodiment of the present application, water level and crack monitoring components 6 are arranged in the middle and on both sides of the working surface 1, that is, water level and crack monitoring components 6 are arranged in the middle and on both sides of the water-conducting crack zone of the working surface 1, so that the water level and crack monitoring components 6 can better cover the entire working surface 1, which is conducive to improving the monitoring precision and accuracy, thereby more quickly and timely feedback of monitoring results.

[0050] The water level and crack monitoring component 6 goes deep into the range below the collapse zone of the working face 1. In one embodiment of the present application, the collapse zone of the working face 1 is located below the water-conducting crack zone, wherein the water-conducting crack zone is located below the bottom aquifer, which enables the water level and crack monitoring component 6 to cover the bottom aquifer, the bottom impermeable layer to the upper part of the coal seam, ensuring that the water level and crack monitoring component 6 can perform water level and crack monitoring operations more quickly and accurately.

[0051] The water level and crack monitoring assembly 6 includes a drill rod, a plurality of water level sensors and a plurality of displacement sensors, and the plurality of water level sensors and the plurality of displacement sensors are arranged in parallel on the drill rod, and the drill rod is inserted into the monitoring hole. In one embodiment of the present application, a plurality of displacement sensors are used to monitor the cracks caused by the sinking of the bottom aquifer. When the bottom aquifer sinks and cracks appear, the water in the bottom aquifer will gradually penetrate into the working surface 1 through the cracks, which will cause the water level in the bottom aquifer to drop, and the plurality of water level sensors are used to monitor the water level in the bottom aquifer. The plurality of water level sensors and the plurality of displacement sensors are arranged in parallel on the drill rod, and then the drill rod is inserted into the monitoring hole, so that the drill rod can block the monitoring hole, which not only prevents the middle aquifer and the bottom aquifer from being connected to each other through the monitoring hole, but also facilitates the precise monitoring of the sensor.

[0052] The waterproof curtain 2 is a pile-connected wall, which includes a plurality of pile foundation units, and adjacent pile foundation units are interlocked and connected. In one embodiment of the present application, the pile-connected wall is formed by interlocking a plurality of pile foundation units, and the pile-connected wall extends from the ground to the bottom waterproof layer, so that the pile-connected wall passes through the middle aquifer and the bottom aquifer, which can prevent the middle aquifer and the bottom aquifer from being connected to each other, thereby minimizing the amount of drainage and grouting operations, which not only reduces construction costs and improves construction efficiency, but also helps to protect the original formation water resources.

[0053] The pile foundation unit is a bored pile, cement mixing pile or rotary excavated pile. In one embodiment of the present application, a suitable pile foundation type can be selected according to the specific geological conditions, and each pile foundation unit is constructed separately, with a small disturbance range during the construction process, and little impact on the underground aquifer and coal seam structure.

[0054] When performing the well drainage operation, a pumping borehole 5 is drilled at a position within the water-conducting fracture zone to the bottom aquifer, and the well drainage operation is performed using the pumping borehole 5. In one embodiment of the present application, a hole is drilled within the water-conducting fracture zone to facilitate faster extraction of the bottom aquifer water body at the upper part of the water-conducting fracture zone, thereby alleviating the threat of the bottom aquifer to the water-conducting fracture zone.

[0055] Before the well drainage operation is performed, at least one isolation pile 4 is first constructed within the water-conducting fracture zone, and the isolation pile 4 extends from the ground through the middle aquifer to the middle aquifer, and then a pumping borehole 5 is drilled in the middle of the isolation pile 4 to the middle and upper part of the bottom aquifer. In one embodiment of the present application, the isolation pile 4 driven into the middle aquifer can be a bored pile or a cement mixing pile or a rotary pile, and then the pumping borehole 5 is driven through the isolation pile 4 into the bottom aquifer, so that the isolation pile 4 can isolate the pumping borehole 5 from the middle aquifer, thereby preventing the middle aquifer from affecting the pumping operation of the pumping borehole 5 on the bottom aquifer.

[0056] The grouting borehole is drilled to the upper part of the bottom aquifer, and the grouting anchor rod 3 is inserted into the grouting borehole for grouting operation. In one embodiment of the present application, the grouting anchor rod 3 is extended to the upper part of the bottom aquifer for grouting operation, and the grouting liquid first fills the gaps in the bottom aquifer, and then gradually accumulates in the bottom aquifer, which also makes the grouting liquid raise the water level of the bottom aquifer in the waterproof curtain 2, so that the pumping borehole 5 extending to the middle and upper part of the bottom aquifer can always effectively pump water until the water in the bottom aquifer in the waterproof curtain 2 is completely extracted. At this time, the grouting liquid also fills the bottom aquifer, thereby completely eliminating the influence of the water body in the bottom aquifer in the waterproof curtain 2 on the working face 1.

[0057] The bottom of the waterproof curtain 2 is lower than the bottom of the grouting anchor 3. In one embodiment of the present application, the waterproof curtain 2 is lower than the grouting anchor 3, which makes it easier for the waterproof curtain 2 to intercept the grouting liquid and avoid the overflow of the grouting liquid, so that the grouting liquid can be effectively kept within the waterproof curtain 2, which is beneficial to improve the effectiveness of the grouting operation and reduce the construction cost.

[0058] It should be understood that the above description is merely exemplary and the embodiments of the present application do not limit this.

[0059] 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 rapid assessment and treatment of water diversion safety in overburden under mining at a working face, characterized in that: The treatment method comprises the following steps: Step 1: Determine the scope of surface subsidence, water-conducting fracture zone and collapse zone after mining of the working face according to the spatial position relationship between the working face and the aquifer, the physical and mechanical parameters of the coal seam where the working face is located and the top and bottom strata of the coal seam, and the hydrological data of the aquifer; From top to bottom, the rock formations include the upper loose layer, the middle aquifer, the middle aquiclude, the bottom aquifer, the bottom aquiclude and the coal seam where the working face is located; Step 2: within the vertical projection range of the working face, a plurality of monitoring holes are drilled from the ground, and a water level and crack monitoring component is arranged in each monitoring hole, wherein the water level and crack monitoring component is used to monitor the water level change of the bottom aquifer and the damage of the overburden rock; Step 3, constructing a waterproof curtain along the boundary of the surface subsidence range, wherein the waterproof curtain extends from the surface to the bottom waterproof layer; Step 4: The working face performs mining operations, and monitors the water level changes of the bottom aquifer and the crack damage of the overburden on the working face in real time through the water level and crack monitoring components; Step 5: when the water level change or the fracture damage range exceeds the first warning value, underground water drainage operation is carried out, and recovery is continued after the underground water inflow reaches a safe value; When the water level change or the scope of fracture damage exceeds the second warning value, conduct a combined operation of drainage from the well and underground drainage, and continue mining after the underground water inflow reaches a safe value; When the water level change or the scope of fracture damage exceeds the third warning value, the water is drained from the well and underground at the same time, grouting holes are drilled from the ground, and the bottom aquifer and the bottom impermeable layer are grouted. After the water in the bottom aquifer within the impermeable curtain is pumped out and filled with grouting liquid and the grouting liquid solidifies, the recovery will continue.

2. The method for rapid assessment and treatment of water diversion safety in overburden under mining at a working face according to claim 1 is characterized in that: Water level and crack monitoring components are installed in the middle and on both sides of the working face.

3. The method for rapid assessment and treatment of water diversion safety in overburden under mining at a working face according to claim 2 is characterized in that: The water level and crack monitoring components extend deep into the working face below the collapse zone.

4. The method for rapid assessment and treatment of water diversion safety in overburden under mining at a working face according to claim 3 is characterized in that: The water level and crack monitoring assembly comprises a drill rod, a plurality of water level sensors and a plurality of displacement sensors, wherein the plurality of water level sensors and the plurality of displacement sensors are arranged in parallel on the drill rod, and the drill rod is inserted into the monitoring hole.

5. The method for rapid assessment and treatment of water diversion safety in overburden under mining at a working face according to claim 1 is characterized in that: The water-blocking curtain is a pile-connected wall, which includes a plurality of pile foundation units, and adjacent pile foundation units are interlocked and connected with each other.

6. The method for rapid assessment and treatment of water diversion safety in overburden under mining at a working face according to claim 5 is characterized in that: The pile foundation unit is a bored pile, a cement mixing pile or a rotary drilling pile.

7. The method for rapid assessment and treatment of water diversion safety in overburden under mining at a working face according to claim 1 is characterized in that: When the water drainage operation is carried out on the well, a pumping borehole is drilled within the water-conducting fracture zone to the bottom aquifer, and the water drainage operation is carried out on the well using the pumping borehole.

8. The method for rapid assessment and treatment of water diversion safety in overburden under mining at a working face according to claim 7 is characterized in that: Before conducting water drainage operations on the well, at least one isolation pile is constructed within the water-conducting fracture zone. The isolation pile extends from the ground through the middle aquifer to the middle aquifer, and then a pumping borehole is drilled in the middle of the isolation pile to the middle and upper part of the bottom aquifer.

9. The method for rapid assessment and treatment of water diversion safety in overburden under mining at a working face according to claim 8 is characterized in that: The grouting borehole is drilled to the upper part of the bottom waterproof layer, and a grouting anchor rod is inserted into the grouting borehole to carry out grouting operation.

10. The method for rapid assessment and treatment of water diversion safety in overburden under mining at a working face according to claim 9, characterized in that: The bottom of the waterproof curtain is lower than the bottom of the grouting anchor rod.

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