阅读说明：本技术 一种考虑采动裂隙影响的注浆防治水害方法 (Grouting water damage prevention and control method considering mining-induced fracture influence ) 是由 杨滨滨 于 2021-08-16 设计创作，主要内容包括：本发明属于矿井水害防治领域,具体涉及一种基于近距离煤层重复采动工况下的考虑采动裂隙影响的注浆防治水害方法。探讨了在两层近距离煤层情况下,上煤层上方存在近距离含水层时的注浆防治水害方法,旨在为近距离煤层群的水砂防治开采提供借鉴。通过预裂形成缓冲层来降低导水裂隙带高度,并通过注浆形成隔水层,以此解决了近距离煤层重复采动情况下的水害防治。(The invention belongs to the field of mine water damage prevention and control, and particularly relates to a grouting water damage prevention and control method considering mining-induced fracture influence under a short-distance coal seam repeated mining working condition. A method for preventing and treating water damage by grouting when a close-distance water-bearing layer exists above an upper coal seam under the condition of two close-distance coal seams is discussed, and the method aims to provide reference for water sand prevention and exploitation of close-distance coal seam groups. The height of a water flowing fractured zone is reduced by forming a buffer layer through pre-splitting, and a water-resisting layer is formed through grouting, so that the water damage prevention and control under the condition of repeated mining of a short-distance coal seam are realized.)

1. A slip casting water damage prevention method considering mining fracture influence comprises the following steps that working conditions comprise an upper coal seam and a lower coal seam which are close in distance, and the distance between the coal seams is Hj; aquifers with a distance of Hh are formed above the upper coal seam in a short distance;

the method for preventing and controlling the water damage is characterized by comprising the following steps:

s1, determining heights Hks and Hkx of a caving zone and heights Hds and Hdx of a water flowing fractured zone when the upper coal seam and the lower coal seam are independently mined respectively;

s2, comparing the height Hkx of the coal caving zone with the distance Hj between the coal seams;

when Hkx is smaller than Hj, comparing the heights of the top boundaries of the water flowing fractured zones of the upper coal seam and the lower coal seam;

when the height of the top landmark of the water flowing fractured zone of the upper coal seam is larger than that of the top landmark of the water flowing fractured zone of the lower coal seam, executing the step S3;

when the elevation of the top boundary of the water flowing fractured zone of the upper coal seam is less than or equal to the elevation of the top boundary of the water flowing fractured zone of the lower coal seam, executing the step S4;

when Hkx is equal to or greater than Hj, step S5 is executed;

s3, backward mining of the working face of the lower coal seam is carried out, backward tunneling of a mining roadway of the working face of the upper coal seam is carried out, and the tunneling progress lags behind the mining progress; constructing a cracking borehole in an upper coal seam water flowing fractured zone in a tunneling stoping roadway which is tunneled on the working face of the upper coal seam, wherein the pre-cracking range of the cracking borehole is a water flowing fractured zone rock stratum within a certain height range above the top boundary of a caving zone, and the cracking borehole is pre-cracked on the top boundary of the caving zone to form a buffer layer with a certain thickness before the upper coal seam is mined;

s4, performing retreat mining on the working face of the upper coal seam, and performing retreat tunneling on a recovery roadway on the working face of the lower coal seam; and the tunneling progress lags the mining progress; constructing a fracturing drill hole in a water diversion fractured zone of a lower coal seam in a stoping roadway which is well tunneled on a working face of the lower coal seam, wherein the pre-fracturing range of the fracturing drill hole is a water diversion fractured zone rock stratum within a certain height range above the top boundary of a caving zone, so that a buffer layer with a certain thickness is formed on the top boundary of the caving zone in advance by fracturing before the lower coal seam is mined;

s5, before the working face of the upper coal seam is mined, a fracturing drill hole is constructed in a water-conducting fractured zone of the upper coal seam in a mining roadway which is well tunneled on the working face of the upper coal seam, the pre-fracturing range of the fracturing drill hole is a water-conducting fractured zone rock stratum within a certain height range above the top boundary of a caving zone, so that a buffer layer with a certain thickness is formed by pre-fracturing on the top boundary of the caving zone before the mining of the upper coal seam, and the top boundary elevation of the buffer layer is greater than that of the caving zone during the mining of the lower coal seam; and during backward mining of the working face of the upper coal seam, backward tunneling of a mining roadway of the working face of the lower coal seam is carried out simultaneously, and then mining of the lower coal seam is carried out.

2. The method for controlling water damage according to claim 1, wherein in step S4, the pre-splitting range is from above the top boundary of the caving zone of the lower coal seam to the bottom of the upper coal seam.

3. The method for preventing and treating water damage according to claim 1, wherein in step S3, when the elevation of the lower coal seam hydraulic fractured zone top boundary is greater than the elevation of the buffer layer top boundary by a certain value, after the buffer layer is constructed, a grouting borehole is constructed in the lower coal seam hydraulic fractured zone at the upper part of the buffer layer in a stoping roadway which has been tunneled on the working face of the upper coal seam, and a proper separation layer position is selected for grouting and water resistance; otherwise, when the upper coal seam is mined, grouting and drilling are conducted in the upper coal seam water diversion fractured zone from the mining roadway of the upper coal seam working face to the rear part and the upper coal seam upper part of the buffer layer, and a proper separation layer position is selected for grouting and water isolation.

4. The method for preventing and treating water damage according to claim 1, wherein in step S4, after the buffer layer is constructed, a grouting borehole is constructed in a water flowing fractured zone of an upper coal seam in a stoping roadway which has been dug on a working surface of a lower coal seam, and a proper separation layer is selected for grouting and water isolation.

5. The method for preventing and treating water damage according to claim 1, wherein in step S5, when the upper portion of the buffer layer still has an upper coal seam water flowing fractured zone with a certain thickness, a grouting drill hole is constructed in a stoping roadway which has been tunneled on the lower coal seam working face to the upper coal seam water flowing fractured zone on the upper portion of the buffer layer, and a proper separation layer position is selected for grouting and water resisting; otherwise, when the lower coal seam is mined, grouting and drilling are conducted in the lower coal seam water diversion fractured zone from the mining roadway of the lower coal seam working face to the rear and to the upper part of the buffer layer, and a proper separation layer position is selected for grouting and water isolation.

6. The method for controlling water damage according to any one of claims 3 to 5, wherein the grouting material is a polyurethane or a flexible waterproof material.

Technical Field

The invention belongs to the field of mine water damage prevention and control, and particularly relates to a grouting water damage prevention and control method considering mining-induced fracture influence under a short-distance coal seam repeated mining working condition.

Background

Coal is usually present underground in a multi-layer form to form a coal seam group, most underground coal mines face the condition of mining multiple coal seams (coal seam group), and are influenced by geological conditions such as the thickness of each coal seam, the distance between the coal seams, the lithology of overlying rocks and the like, the coal seam mining has the possibility of interaction, and the possibility of disaster occurrence in the mining process is greatly increased, particularly when a short-distance water-bearing layer exists above the coal seam group.

The coal seam group mining has two modes of upward mining and downward mining, and after the mining of the previous coal seam is completed, the mining of the later coal seam can be performed above or below the previous coal seam, so that the problems of repeated damage of overlying strata and movement control of mining rock strata can be caused. For example, the interaction of the coal seams increases the migration path of water and sand, and when a near-distance aquifer exists above the coal seam group, the working face is communicated with the aquifer, and a water burst and sand bursting disaster occurs. Therefore, how to reduce the height of the water sand migration channel during the close-distance coal seam group mining has important significance for the prevention and control of water damage of the coal mine and the mining design.

Disclosure of Invention

Aiming at the defects of the prior art, the invention discusses a grouting water damage prevention and control method when a close-distance water-bearing layer exists above an upper coal seam under the condition of two close-distance coal seams, and aims to provide reference for water sand prevention and control exploitation of close-distance coal seam groups, and the method is as follows specifically

A slip casting water damage prevention method considering mining fracture influence comprises the following steps that working conditions comprise an upper coal seam and a lower coal seam which are close in distance, and the distance between the coal seams is Hj; aquifers with a distance of Hh are formed above the upper coal seam in a short distance; the method for preventing and controlling the water damage comprises the following steps:

s1, determining heights Hks and Hkx of a caving zone and heights Hds and Hdx of a water flowing fractured zone when the upper coal seam and the lower coal seam are independently mined respectively;

s2, comparing the height Hkx of the coal caving zone with the distance Hj between the coal seams;

when Hkx is smaller than Hj, comparing the heights of the top boundaries of the water flowing fractured zones of the upper coal seam and the lower coal seam;

when the height of the top landmark of the water flowing fractured zone of the upper coal seam is larger than that of the top landmark of the water flowing fractured zone of the lower coal seam, executing the step S3;

when the elevation of the top boundary of the water flowing fractured zone of the upper coal seam is less than or equal to the elevation of the top boundary of the water flowing fractured zone of the lower coal seam, executing the step S4;

when Hkx is equal to or greater than Hj, step S5 is executed;

s3, backward mining of the working face of the lower coal seam is carried out, backward tunneling of a mining roadway of the working face of the upper coal seam is carried out, and the tunneling progress lags behind the mining progress; constructing a cracking borehole in an upper coal seam water flowing fractured zone in a tunneling stoping roadway which is tunneled on the working face of the upper coal seam, wherein the pre-cracking range of the cracking borehole is a water flowing fractured zone rock stratum within a certain height range above the top boundary of a caving zone, and the cracking borehole is pre-cracked on the top boundary of the caving zone to form a buffer layer with a certain thickness before the upper coal seam is mined;

preferably, in step S3, the heading face of the stoping roadway of the upper coal seam is out of the mining dynamic influence range of the lower coal seam.

S4, performing retreat mining on the working face of the upper coal seam, and performing retreat tunneling on a recovery roadway on the working face of the lower coal seam; and the tunneling progress lags the mining progress; constructing a fracturing drill hole in a water diversion fractured zone of a lower coal seam in a stoping roadway which is well tunneled on a working face of the lower coal seam, wherein the pre-fracturing range of the fracturing drill hole is a water diversion fractured zone rock stratum within a certain height range above the top boundary of a caving zone, so that a buffer layer with a certain thickness is formed on the top boundary of the caving zone in advance by fracturing before the lower coal seam is mined;

preferably, in step S4, the pre-splitting range is above the top boundary of the lower coal seam caving zone to the upper coal seam floor.

S5, before the working face of the upper coal seam is mined, a fracturing drill hole is constructed in a water-conducting fractured zone of the upper coal seam in a mining roadway which is well tunneled on the working face of the upper coal seam, the pre-fracturing range of the fracturing drill hole is a water-conducting fractured zone rock stratum within a certain height range above the top boundary of a caving zone, so that a buffer layer with a certain thickness is formed by pre-fracturing on the top boundary of the caving zone before the mining of the upper coal seam, and the top boundary elevation of the buffer layer is greater than that of the caving zone during the mining of the lower coal seam; and during backward mining of the working face of the upper coal seam, backward tunneling of a mining roadway of the working face of the lower coal seam is carried out simultaneously, and then mining of the lower coal seam is carried out.

Preferably, in step S3, when the elevation of the top boundary of the lower coal seam hydraulic fractured zone is greater than the elevation of the top boundary of the buffer layer by a certain value, after the buffer layer is constructed, constructing a grouting borehole in the lower coal seam hydraulic fractured zone at the upper part of the buffer layer in a stoping roadway which has been tunneled on the working surface of the upper coal seam, and selecting a proper separation layer for grouting and water-resisting;

further, the separation layer position is the highest separation layer position in the lower coal seam water diversion fracture zone.

Otherwise, when the upper coal seam is mined, grouting and drilling are conducted in the upper coal seam water diversion fractured zone from the mining roadway of the upper coal seam working face to the rear part and the upper coal seam upper part of the buffer layer, and a proper separation layer position is selected for grouting and water isolation.

Further, the separation layer position is the highest separation layer position in the upper coal layer water flowing fracture zone.

Preferably, in step S4, after the buffer layer is constructed, a grouting borehole is constructed in the upper coal seam water diversion fractured zone in the stoping roadway which has been tunneled on the lower coal seam working face, and a suitable separation layer position is selected for grouting and water isolation.

Further, the separation layer position is the highest separation layer position in the upper coal layer water flowing fracture zone.

Preferably, in step S5, when the upper portion of the buffer layer still has an upper coal seam water flowing fractured zone with a certain thickness, a grouting borehole is constructed in a stoping roadway which has been tunneled on the lower coal seam working face into the upper coal seam water flowing fractured zone on the upper portion of the buffer layer, and a proper separation layer position is selected for grouting and water isolation;

further, the separation layer position is the highest separation layer position in the upper coal layer water flowing fracture zone.

Otherwise, when the lower coal seam is mined, grouting and drilling are conducted in the lower coal seam water diversion fractured zone from the mining roadway of the lower coal seam working face to the rear and to the upper part of the buffer layer, and a proper separation layer position is selected for grouting and water isolation.

Further, the separation layer position is the highest separation layer position in the lower coal seam water diversion fracture zone.

Preferably, the grouting material is a poly-pressure gum, i.e. a novel high-molecular double-liquid grouting material, which is composed of resin and a catalyst respectively.

Preferably, the grouting material is a flexible waterproof material, such as asphalt.

The beneficial technical effects of the invention are as follows: the invention reduces the height of the water flowing fractured zone by forming the buffer layer through pre-splitting and forms the water-resisting layer through grouting, thereby solving the problem of water damage prevention and control under the condition of repeated mining of the close-range coal seam. The technical effects obtained by the technical means and the corresponding technical means are detailed in the following detailed description.

Drawings

FIG. 1 is a construction flow chart of a grouting water damage prevention and control method considering mining-induced fracture influence according to the invention;

Detailed Description

A slip casting water damage prevention method considering mining fracture influence, the working condition includes upper coal seam, lower coal seam of the similar distance; the distance between the upper coal seam and the lower coal seam is Hj, namely the thickness of a rock stratum between the upper coal seam and the lower coal seam is Hj; a water-bearing layer is arranged above the upper coal layer in a short distance, and the distance between the upper coal layer and the water-bearing layer is Hh; the water damage comes from a water-bearing stratum, and mining fractures are caving zones and water diversion fracture zones generated by coal seam mining;

the method for preventing and controlling the water damage comprises the following steps:

s1, determining the heights Hks and Hkx of caving zones and the heights Hds and Hdx of water diversion fractured zones when the upper coal seam and the lower coal seam are respectively and independently mined according to the lithology of overlying strata above the coal seam and by combining working conditions such as mining height of the coal seam;

s2, comparing the height Hkx of the coal caving zone with the distance Hj between the coal seams;

when the height Hkx of the coal seam caving zone is smaller than the coal seam distance Hj, comparing the top boundary elevations of the water flowing fractured zones of the upper coal seam and the lower coal seam;

when the top landmark of the water flowing fractured zone of the upper coal seam is higher than the top boundary elevation of the water flowing fractured zone of the lower coal seam (namely the top boundary of the water flowing fractured zone is closer to the aquifer than the top boundary of the water flowing fractured zone when the upper coal seam is independently mined), namely Hds + Hj is larger than Hdx, adopting ascending mining, namely mining the lower coal seam before mining the upper coal seam, and specifically executing the step S3;

when the elevation of the top boundary of the water flowing fractured zone of the upper coal seam is smaller than or equal to the elevation of the top boundary of the water flowing fractured zone of the lower coal seam (namely the top boundary of the water flowing fractured zone is farther from or the same as the water containing layer when the upper coal seam is independently mined than the top boundary of the water flowing fractured zone when the lower coal seam is independently mined), namely Hds + Hj is smaller than or equal to Hdx, adopting downward mining, namely mining the upper coal seam first and then mining the lower coal seam, and specifically executing the step S4;

under the condition, the coal bed corresponding to the low elevation of the top boundary of the water flowing fractured zone (the top boundary of the water flowing fractured zone is far away from the aquifer) is mined firstly, so that the water flowing fractured zone of the coal bed mined firstly is not communicated with the aquifer (at least the possibility of communication is reduced), and the work of reducing the height of the water flowing fractured zone is carried out for mining the coal bed mined later (see below) when the coal bed mined firstly is mined;

when the caving zone height Hkx of the lower coal seam is greater than or equal to the coal seam distance Hj, the upper coal seam is completely collapsed due to the fact that the upper coal seam is mined firstly, and therefore mining laneways are difficult to arrange and follow-up mining is difficult to achieve, therefore, downward mining must be adopted, namely, the upper coal seam is mined firstly and then the lower coal seam is mined, and the step S5 is specifically executed;

s3, performing retreat mining on the working face of the lower coal seam, and performing retreat tunneling (the tunneling direction of the upper coal seam is consistent with the mining direction of the lower coal seam) on the stoping roadway (including a transportation roadway and a return airway) of the working face of the upper coal seam; the tunneling of the stoping roadway of the working face of the upper coal seam is influenced by the mining of the lower coal seam, so that the tunneling progress of the stoping roadway of the working face of the upper coal seam lags behind the mining progress of the working face of the lower coal seam; preferably, the excavation face of the stoping roadway of the working face of the upper coal seam is outside the mining dynamic influence range of the lower coal seam;

constructing a cracking drill hole in an upward coal seam water flowing fractured zone in a stoping roadway which is well tunneled on the working face of an upper coal seam, wherein the pre-cracking range of the cracking drill hole is a water flowing fractured zone rock stratum within a certain height range above the top boundary of a caving zone, so that a buffer layer with a certain thickness is formed on the top boundary of the caving zone in advance before the upper coal seam is mined (the buffer layer can increase the crushing and swelling amount, absorb part of mining damage energy and prevent part of mining damage energy from being uploaded), the transfer height of fractures during the upper coal seam mining is reduced, and the height of the water flowing fractured zone of the upper coal seam mining is reduced;

s4, performing retreat mining on the working face of the upper coal seam, and performing retreat tunneling on a stoping roadway (comprising a transportation roadway and a return airway) of the working face of the lower coal seam (the tunneling direction of the lower coal seam is consistent with the mining direction of the upper coal seam); the tunneling progress of a mining roadway of the lower coal seam working face lags the mining progress of the upper coal seam working face;

constructing a fracturing drill hole in a water-conducting fractured zone of a lower coal seam in a stoping roadway which is well tunneled on a working face of the lower coal seam, wherein the pre-fracturing range of the fracturing drill hole is a water-conducting fractured zone rock stratum within a certain height range above the top boundary of a caving zone, so that a buffer layer with a certain thickness is formed on the top boundary of the caving zone in advance by fracturing before the lower coal seam is mined, and the transfer height of fractures during the mining of the lower coal seam is reduced, namely the height of the water-conducting fractured zone of the lower coal seam is reduced;

preferably, the pre-splitting range can be from the top boundary of the lower coal seam caving zone to the top coal seam floor, and the buffer layer ranges from the top boundary of the lower coal seam caving zone to the top boundary of the upper coal seam caving zone;

s5, before the working face of the upper coal seam is mined, a fracturing drilling hole is constructed in a water-conducting fractured zone of the upper coal seam in a mining roadway which is well tunneled on the working face of the upper coal seam, the pre-fracturing range of the fracturing drilling hole is a water-conducting fractured zone rock stratum within a certain height range above the top boundary of a caving zone, and the fracturing is performed on the top boundary of the caving zone in advance to form a buffer layer with a certain thickness before the mining of the upper coal seam, so that the transfer height of fractures during the mining of the upper coal seam is reduced, namely, the height of the water-conducting fractured zone during the mining of the upper coal seam is reduced, and the height of a comprehensive water-conducting fractured zone during the mining of the lower coal seam is reduced; the top boundary elevation of the buffer layer is greater than the top boundary elevation of a caving zone during the mining of the lower coal seam;

and during backward mining of the working face of the upper coal seam, backward tunneling of a mining roadway of the working face of the lower coal seam is carried out simultaneously, and then mining of the lower coal seam is carried out.

Preferably, the method further comprises the step of grouting isolation, as follows

In step S3, when the elevation of the top boundary of the lower coal seam water flowing fractured zone is greater than the elevation of the top boundary of the buffer layer by a certain value, that is, when the upper portion of the buffer layer still has a lower coal seam water flowing fractured zone with a certain thickness, after the buffer layer is constructed, a grouting borehole is constructed in the lower coal seam water flowing fractured zone at the upper portion of the buffer layer in the stoping roadway which has been tunneled at the upper coal seam working face, a proper separation layer position is selected for grouting, and a filling body is formed by grouting to block water and cut off the water flowing channel of the lower coal seam (grouting to block the longitudinal and transverse fractures in the water flowing fractured zone, sealing the water blocking channel, the same as below). The highest separation layer position in the lower coal seam water flowing fractured zone is preferably selected as the separation layer position (the longitudinal fractures are few, the slurry leakage is less, the grouting amount is less, and the water-resisting effect is good); this situation is a precaution.

Otherwise, when the upper coal seam is mined, constructing a grouting drill hole from the mining roadway of the working face of the upper coal seam backwards to the upper coal seam water diversion fractured zone at the upper part of the buffer layer, selecting a proper separation layer position for grouting, and forming a filling body through grouting to isolate water and cut off a water diversion channel of the lower coal seam; this situation is a remedy.

In the step S4, after the buffer layer is constructed, grouting and drilling are conducted in the upper coal seam water diversion fractured zone in the excavation roadway which is excavated on the working face of the lower coal seam, appropriate separation layer position grouting is selected, and a filling body is formed through grouting to block water and cut off a water diversion channel of the lower coal seam. The separation layer position is preferably the highest separation layer position in the upper coal seam water flowing fractured zone.

In step S5, when the upper portion of the buffer layer still has an upper coal seam water diversion fractured zone with a certain thickness, a grouting drill hole is constructed in a stoping roadway which has been tunneled on the working face of the lower coal seam to the upper coal seam water diversion fractured zone on the upper portion of the buffer layer, a proper separation layer position is selected for grouting, and a filling body is formed through grouting to block water and cut off a water diversion channel of the lower coal seam. The separation layer position is preferably the highest separation layer position in the upper coal seam water diversion fracture zone; this situation is a precaution.

Otherwise, when the lower coal seam is mined, constructing a grouting drill hole from a mining roadway of the working surface of the lower coal seam backwards to the lower coal seam water diversion fractured zone at the upper part of the buffer layer, selecting a proper separation layer position for grouting, and forming a filling body through grouting to isolate water and cut off a water diversion channel of the lower coal seam; this situation is a remedy.

Preferably, the grouting material is a poly-pressure gum, i.e. a novel high-molecular double-liquid grouting material, which is composed of resin and a catalyst respectively.

Preferably, the grouting material is a flexible waterproof material, such as asphalt. The flexible waterproof material can generate certain deformation and can still block the crack after being influenced by mining; while hard waterproof materials, such as cement, crack and continue to produce cracks after being affected by mining, thereby conducting water diversion.