Method for blocking harmful gas in goaf through grouting of flyover crossing roadway

Abstract

The invention relates to the technical field of coal mine roadway harmful gas blocking, in particular to a method for blocking goaf harmful gas through vertical crossing roadway grouting, which comprises the following steps of: A, determining a vertical crossing fresh air flow lower roadway at an upper air head of an air leakage point; b, determining the position and boundary of the flyover crossing in the lower roadway; c, a drilling machine and a grouting operation platform are built in the lower roadway; d, drill hole positions and drill hole intervals are determined in the lower roadway, drill holes are constructed one by one, the construction steps comprise punching, implanting and hole sealing, the drill hole types comprise the first drill hole type and the second drill hole type, the first drill hole type and the second drill hole type are arranged at intervals, the first drill hole type is used for implanting a framework anchor cable, and the second drill hole type is used for implanting a grouting pipe; and E, high-expansion quick-setting grouting materials are injected into the grouting pipes in the lower roadway, and the blocking wall is constructed. According to the method, the ventilation negative pressure in construction is small, the plugging construction work amount is small, the construction speed is high, the plugging compaction effect is good, meanwhile, frequent shift change and alternate operation are avoided, and the safety of constructors is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of coal mine roadway harmful gas plugging, in particular to a method for plugging harmful gas in goaf by grouting in three-dimensional crossing roadway. BACKGROUND

[0002] The coal mine return air roadway undertakes the function of discharging various harmful gases in the mine ventilation, and when the return air roadway is arranged adjacent to the goaf, in order to prevent the harmful gases in the goaf from overflowing along the bypass roadway to the return air roadway, a sealing wall is generally constructed for the bypass roadway to perform the closed treatment. However, due to the large ventilation negative pressure of the return air roadway, the sealing wall is obviously affected by the mining pressure and is prone to deformation and cracking, and after a long time, the sealing wall is prone to air leakage, at which time the harmful gases (such as CO, CH4, etc.) in the goaf are easy to flow into the return air roadway through the return air leakage point, thereby causing the concentration of harmful gases in the return air roadway to increase, and exceeding a certain concentration will endanger personal safety.

[0003] For this type of air leakage point, construction personnel generally need to enter the return air roadway to the air leakage point to directly spray the sealing wall for plugging treatment, or to drill holes in the sealing wall and pass through the grouting pipe for grouting to re-construct the air blocking wall to achieve the filling and plugging effect. However, when the concentration of harmful gases in the return air roadway is high, the concentration of harmful gases at the corresponding return air leakage point even exceeds 1000PPm, and even if the construction personnel carry breathing machines and frequently change shifts to work alternately, it still poses a threat to the safety of the construction personnel in the toxic and harmful gas return air flow, and at the same time, the ventilation negative pressure at the air leakage point is large, the effect of the spray plugging is poor, and the period for re-constructing the plugging wall is long, so the above treatment method is difficult to meet the technical requirement of rapid plugging in a complex and harsh environment. SUMMARY

[0004] The present application aims to provide a method for plugging harmful gas in goaf by grouting in three-dimensional crossing roadway to solve the problems raised in the background.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solution: a method for plugging harmful gas in goaf by grouting in three-dimensional crossing roadway, comprising the following steps: Step A: determining a fresh air flow lower roadway intersecting the cleaning inclined roadway in the upper air head of the sealing wall air leakage point of the cleaning inclined roadway; Step B: determining the position and boundary of the lower roadway intersecting the cleaning inclined roadway in the lower roadway, and further determining the cleaning inclined roadway slope head flat roadway plugging section of the cleaning inclined roadway at the three-dimensional intersection position; Step C: building a drilling machine and grouting operation platform in the lower roadway; Step D: determine the drilling position, drilling diameter, drilling depth and drilling spacing in the full section of the sealing section of the slope head flat roadway of the cleaning inclined roadway within the boundary of the three-dimensional intersection in the lower roadway, and drill each hole. The construction steps of each drilling hole include drilling, implantation and hole sealing. The types of drilling holes include drilling hole type one and drilling hole type two. Drilling hole type one and drilling hole type two are arranged at intervals. Drilling hole type one is used to implant a skeleton anchor cable in the sealing section of the slope head flat roadway of the cleaning inclined roadway. Drilling hole type two is used to implant a grouting pipe in the sealing section of the slope head flat roadway of the cleaning inclined roadway. The skeleton anchor cable and the grouting pipe together play the role of blocking the grid; Step E: inject high-expansion fast-setting grouting material into the grouting pipe implanted in the sealing section of the slope head flat roadway of the cleaning inclined roadway in the lower roadway to build a sealing wall, and fill the separation layer cracks between the roof of the lower roadway and the floor of the cleaning inclined roadway.

[0006] Optionally, in step D, the drilling holes are sorted in order. The sequence numbers one, three, five, etc. are drilling hole type two, and the sequence numbers two, four, six, etc. are drilling hole type one. The drilling sequence is according to the sequence numbers two-one-four-three-six-five, etc. After completing the construction of each drilling hole type two, the corresponding grouting operation of the grouting pipe is immediately implemented.

[0007] Optionally, in step C, a grouting operation platform is built 15m from the upwind head at the three-dimensional intersection position in the lower roadway; and in step D, the drilling sequence direction is along the downwind flow direction of the lower roadway, and starts from the side of the upwind head of the sealing section of the slope head flat roadway of the cleaning inclined roadway.

[0008] Optionally, in step D, the drilling diameter is 26-30mm, and the drilling spacing is 1-1.3m. The drilling diameters of drilling hole type one and drilling hole type two are equal.

[0009] Optionally, in step D, drilling hole type one and drilling hole type two both penetrate the floor of the cleaning inclined roadway. The skeleton anchor cable passes through drilling hole type one and extends into the cleaning inclined roadway and is implanted into the roof of the sealing section of the slope head flat roadway of the cleaning inclined roadway. The grouting pipe passes through drilling hole type two and extends into the cleaning inclined roadway and is implanted into the roof of the sealing section of the slope head flat roadway of the cleaning inclined roadway.

[0010] Optionally, in step D, the types of drilling holes further include drilling hole type three. Drilling hole type one, drilling hole type two and drilling hole type three are arranged at intervals. Drilling hole type three does not penetrate the floor of the cleaning inclined roadway. Drilling hole type three is used to implant a short anchor cable in the roof of the lower roadway and the floor of the cleaning inclined roadway.

[0011] Optionally, the high-expansion fast-setting grouting material is a coal mine filling airtight phenolic resin foaming material.

[0012] Optionally, in step E, monitoring points are arranged at the downwind head of the air return roadway at the air leakage point of the sealing wall and at the downwind head of the lower roadway at the three-dimensional intersection position before grouting, and the concentration change of harmful gas is monitored on line through the monitoring points during grouting, and the grouting parameters are adjusted in time according to the monitoring data.

[0013] Optionally, the method further comprises Step F: After the construction of the sealing wall, the air return roadway at the air leakage point of the sealing wall is treated by spraying and sealing to block the air leakage.

[0014] Optionally, the upper segment of the skeleton anchor cable and the upper segment of the grouting pipe are sleeved with an elastic support member which can expand outward under pressure, and the elastic support member is used to block the grid after expanding outward, preventing the flowing of the foaming slurry from being too far; the elastic support member comprises an upper sleeve ring and a lower sleeve ring which are distributed in an up-down spacing, a plurality of elastic support ribs with a certain arc are connected between the lower end surface of the upper sleeve ring and the upper end surface of the lower sleeve ring in a circumferential direction, the lower end of the lower sleeve ring is connected with a locking ring, the outer surface of the locking ring is a conical surface, a plurality of axial through cutting slits are formed in the lower end of the locking ring, and a locking nut is threadedly connected outside the locking ring.

[0015] Compared with the prior art, the present application has the following advantages: 1. The present application constructs in the lower roadway at the position of the upwind head of the cleaned inclined roadway and the three-dimensional intersection, and constructs a sealing wall in the slope head flat roadway sealing section of the cleaned inclined roadway, the ventilation negative pressure at this construction position is small, the sealing construction engineering quantity is small, the construction speed is fast, the sealing effect is good, and the frequent shift work is avoided, ensuring the safety of the construction personnel. 2. The skeleton anchor cable and the grouting pipe are implanted in the slope head flat roadway sealing section of the cleaned inclined roadway and play the role of blocking the grid, preventing the foaming slurry from flowing too far, and avoiding waste of materials; at the same time, the skeleton anchor cable and the grouting pipe play the role of skeleton bearing in the slope head flat roadway sealing section of the cleaned inclined roadway, enhancing the overall compressive strength of the filling body of the slope head flat roadway sealing section of the cleaned inclined roadway, and preventing blowing and dumping under the action of negative pressure ventilation. 3. The drilling construction sequence of the present application is in the order of two-one-four-three-six-five…, after completing the construction of each drilling two, the corresponding grouting pipe is immediately implemented for grouting operation, which can reduce the harmful gas leakage amount of the drilling fissure in the grouting process, reduce the external overflow concentration of harmful gas in the lower roadway, and further protect the safety of the construction personnel. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The present application is a schematic diagram of roadway distribution and sealing for the embodiment; Figure 2 The present application is a schematic diagram of roadway distribution and sealing for the embodiment; Figure 1 The present application is a schematic diagram of roadway distribution and sealing for the embodiment; Figure 3 Figure 1 is a structural schematic diagram of the elastic support in the framework anchor cable in the application; Figure 4 Figure 2 is a structural schematic diagram of the elastic support on the grouting pipe in the application.

[0017] In the figure: 1, framework anchor cable; 2, grouting pipe; 3, elastic support; 301, upper sleeve ring; 302, lower sleeve ring; 303, elastic support rib; 304, locking ring; 305, cutting seam; 306, locking nut. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the application will be apparently and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the application.

[0019] Please refer to Figure 1 and Figure 2 shown, it is a roadway distribution and sealing schematic diagram of a certain area actually surveyed. Through monitoring, the CO concentration of the air return flow in the air return roadway exceeds 90PPm, the air leakage at two airtight walls in the air return roadway is serious, the on-site measured CO concentration at the two air leakage points exceeds 1000PPm, and the monitoring data shows that the CO concentration has a gradual rising trend in the last three days, which causes a great threat to the safety production of the coal mine.

[0020] The lower roadway is three-dimensionally and obliquely intersected with the overlying cleaning inclined roadway, the layer spacing is about 3m, the cleaning inclined roadway is arranged in the coal seam, and the width x the average height = 3.0m x 2.5m; the lower roadway is located in the coal floor, and the width x the average height = 4.5m x 3.5m. The CO concentration in the air return flow of the air return roadway is not more than 24PPm (the value specified in the coal mine safety regulations) through the following sealing method, which creates a good working condition for ensuring the safety of mine ventilation, and the technical and economic benefits are very significant. Now the sealing method will be described, The embodiment of the application provides a method for sealing gob harmful gas by grouting in a three-dimensionally intersected roadway, which comprises the following steps: Step A: determining a fresh air flow lower roadway which is three-dimensionally intersected with the cleaning inclined roadway at the upwind head of the cleaning inclined roadway located at the air leakage point of the airtight wall; Step B: determining the position and boundary of the three-dimensionally intersected lower roadway with the cleaning inclined roadway, and further determining the cleaning inclined roadway slope head roadway sealing section of the cleaning inclined roadway at the three-dimensionally intersected position; Step C: building a drilling machine in the lower roadway at the three-dimensionally intersected position, and building a grouting operation platform at the upwind head 15m away from the three-dimensionally intersected position; Step D: Determine the drilling position, drilling diameter, drilling depth and drilling spacing in the full section of the sealing section of the slope head flat roadway within the boundary of the three-dimensional intersection in the lower roadway, and drill each hole. The construction steps of each drilling hole include drilling, implantation and hole sealing. The types of drilling holes include drilling hole type one and drilling hole type two. Drilling hole type one and drilling hole type two are arranged alternately. Drilling hole type one is used for implanting the skeleton anchor cable 1 in the sealing section of the slope head flat roadway of the cleaning inclined roadway. Drilling hole type two is used for implanting the grouting pipe 2 in the sealing section of the slope head flat roadway of the cleaning inclined roadway. The skeleton anchor cable 1 and the grouting pipe 2 together play the role of blocking the grid. Step E: Inject high-expansion fast-setting grouting material into the grouting pipe 2 implanted in the sealing section of the slope head flat roadway of the cleaning inclined roadway in the lower roadway to build a sealing wall, and fill the separation layer cracks between the roof of the lower roadway and the floor of the cleaning inclined roadway. Step F: After the sealing wall is built, the air return roadway is repaired by spraying and sealing at the air leakage point of the sealing wall to block the air leakage.

[0021] When the skeleton anchor cable 1 is constructed and supported, it will penetrate the roof of the lower roadway and the floor of the cleaning inclined roadway and enter the cleaning inclined roadway, causing CO in the overlying intersection roadway to flow into the lower roadway along the drilling holes and separation layer cracks under the action of ventilation negative pressure. In step D of the embodiment, the drilling holes are sequentially sorted. The serial numbers one, three, five, … are drilling hole type two, and the serial numbers two, four, six, … are drilling hole type one. The drilling sequence is according to the serial numbers two-one-four-three-six-five. After completing the construction of each drilling hole type two, the corresponding grouting pipe 2 is immediately implemented. This can reduce the harmful gas leakage amount of the separation layer cracks during the grouting process, reduce the external overflow concentration of harmful gases in the lower roadway, and further protect the safety of the construction personnel.

[0022] On the basis of the above embodiment, in step D, the drilling sequence direction is along the leeside flow direction of the lower roadway, and starts from the side of the upwind head of the sealing section of the slope head flat roadway of the cleaning inclined roadway. The drilling diameter is 26-30mm. In this embodiment, the drilling diameters of drilling hole type one and drilling hole type two are both 28mm. The drilling spacing is 1-1.3m. The drilling diameters of drilling hole type one and drilling hole type two are equal, which is convenient for construction and emergency mutual use, and provides work efficiency. According to the interlayer spacing and the layer height of the cleaning inclined roadway, the size of the skeleton anchor cable 1 is Φ22mm×6-7m.

[0023] It should be noted that in step D, both the first type of drilling and the second type of drilling will clean the inclined roadway floor, the skeleton anchor 1 will pass through the first type of drilling and extend into the cleaning inclined roadway and be implanted in the top plate of the sealing section of the cleaning inclined roadway at the slope head, and the grouting pipe 2 will pass through the second type of drilling and extend into the cleaning inclined roadway and be implanted in the top plate of the sealing section of the cleaning inclined roadway at the slope head. When grouting, the grouting pipe 2 together with the skeleton anchor 1 adjacent to its two sides can play a role in blocking the grid fence, which can prevent the flowing of the slurry being coagulated and foamed too far, avoid wasting materials, and at the same time, the upper half of the skeleton anchor 1 and the grouting pipe 2 can play a role in skeleton bearing at the sealing section of the cleaning inclined roadway at the slope head, which can enhance the overall compressive strength of the filling body of the sealing section of the cleaning inclined roadway at the slope head, and prevent blowing and dumping under the action of negative pressure ventilation.

[0024] On the basis of the above-mentioned embodiment, in order to improve the overall compressive strength of the coal floor filling slurry, in step D, the type of drilling also includes the third type of drilling, the first type of drilling, the second type of drilling and the third type of drilling are arranged in sequence and at intervals, the third type of drilling does not penetrate the cleaning inclined roadway floor, and the third type of drilling is used to implant short anchor cables in the lower roadway roof and the cleaning inclined roadway floor. According to the interlayer spacing, the size of the short anchor cable is Φ22mm×3m, and the drilling diameter of the third type of drilling is equal to that of the first type of drilling, B. The short anchor cable and the lower half of the grouting pipe 2 can play a role in skeleton bearing in the coal floor, which can enhance the overall compressive strength of the filling body.

[0025] In this embodiment, the high-expansion quick-setting grouting material is a coal mine filling sealing phenolic resin foaming material, such as the Maifuyn (CTPF type) produced by Shijiazhuang Guosheng Mining Technology Co., Ltd. for emergency grouting sealing construction. Maifuyn is a reactive organic polymer grouting filling material, which has the advantages of timely foaming, low foaming temperature, large expansion ratio, small filling amount, stable and durable foam body performance, etc.

[0026] On the basis of the above-mentioned embodiment, in step E, monitoring points are arranged at the downwind head of the air return roadway at the air leakage point of the sealing wall and at the downwind head of the lower roadway at the three-dimensional intersection position before grouting. During grouting, the change of harmful gas concentration is monitored online through the monitoring points, and the grouting parameters are adjusted in time according to the monitoring data.

[0027] Please refer to Figure 3 and Figure 4As shown, on the basis of the above embodiment, the upper section of the skeleton anchor cable 1 and the upper section of the grouting pipe 2 are sleeved with an elastic support 3 which can expand outwardly and deform under pressure at the front end, the elastic support 3 is used to play a role of blocking grid to high-expansion fast-setting grouting material after outwardly and deforming, preventing the flowing of the foaming slurry which is in the process of solidification from being too far; the elastic support 3 comprises upper and lower sleeves 301 and 302 which are distributed with an up-down spacing, a plurality of elastic support ribs 303 with a certain arc are connected in the circumferential direction between the lower end surface of the upper sleeve 301 and the upper end surface of the lower sleeve 302, the lower end of the lower sleeve 302 is connected with a locking ring 304, the outer surface of the locking ring 304 is a conical surface, a plurality of axial through cutting slits 305 are arranged on the lower end of the locking ring 304, and a locking nut 306 is further threadedly connected outside the locking ring 304. When the locking nut 306 is loosened, the position of the elastic support 3 can be adjusted, and when it is tightened, it is convenient to install and fix it, so that the upper sleeve 301 can withstand a certain degree of extrusion, so that the elastic support rib 303 expands and deforms outwardly.

[0028] Although embodiments of the present application have been shown and described, it is to be understood that various modifications, substitutions, replacements and variations can be made to these embodiments without departing from the principles and spirit of the present application, the scope of the present application being defined by the appended claims and their equivalents.

Claims

1. A method for sealing harmful gases in goafs by grouting in three-dimensional cross tunnels, characterized in that: The steps include: Step A: Determine a fresh airflow down lane that intersects the cleaning inclined lane at the upwind side of the air leakage point of the closed wall; Step B: Determine the position and boundary of the intersection with the cleaning inclined lane in the lower lane, and then determine the blocking section of the cleaning inclined lane at the slope head of the cleaning inclined lane at the intersection; Step C: Set up the drilling rig and grouting platform in the lower tunnel; Step D: Determine the drilling position, drilling diameter, drilling depth and drilling spacing along the entire cross section of the cleaning inclined lane, slope head and flat lane blocking section within the boundary of the three-dimensional intersection in the lower tunnel, and construct the drilling holes one by one. The construction steps of each drilling hole include drilling-implanting-sealing, wherein the types of drilling holes include drilling type 1 and drilling type 2, and the drilling type 1 and drilling type 2 are arranged at intervals. The drilling type 1 is used to implant the skeleton anchor cable (1) in the cleaning inclined lane, slope head and flat lane blocking section, and the drilling type 2 is used to implant the grouting pipe (2) in the cleaning inclined lane, slope head and flat lane blocking section. The skeleton anchor cable (1) and the grouting pipe (2) together play the role of blocking the grid; Step E: Inject high expansion fast setting grouting material into the grouting pipe (2) implanted in the blocking section of the cleaning inclined lane slope head and level lane in the lower lane to construct a blocking wall and fill the separation cracks between the lower lane roof and the cleaning inclined lane bottom plate.

2. The method for sealing harmful gases in goaf by grouting in a three-dimensional intersection tunnel according to claim 1, characterized in that: In step D, the boreholes are sorted in order, with serial numbers 1, 3, 5... being class II boreholes, and serial numbers 2, 4, 6... being class I boreholes. The construction sequence of the boreholes is 2-1-4-3-6-5..., and upon completion of each class II borehole, the grouting operation of the corresponding grouting pipe (2) is immediately carried out.

3. The method for sealing harmful gases in goaf by grouting in a three-dimensional intersection tunnel according to claim 1, characterized in that: In step C, it is built 15m upwind of the three-dimensional intersection in the lower tunnel; in step D, the drilling construction sequence is carried out in the direction of the counterwind flow of the lower tunnel, and starts from the side of the upwind side of the blocking section of the slope head and flat tunnel towards the cleaning direction.

4. The method for sealing harmful gases in goaf by grouting in a three-dimensional intersection tunnel according to claim 1, characterized in that: In step D, the diameter of the drill hole is 26-30 mm, and the drill hole spacing is 1-1.3 m; the drill hole diameters of the first and second drill holes are equal.

5. The method for sealing harmful gases in goaf by grouting in a three-dimensional intersection tunnel according to claim 4, characterized in that: In step D, the first and second drilling holes will penetrate the bottom plate of the cleaning inclined tunnel, the skeleton anchor cable (1) will pass through the first drilling hole and extend into the cleaning inclined tunnel and be implanted into the top plate of the cleaning inclined tunnel slope head and flat tunnel plugging section, and the grouting pipe (2) will pass through the second drilling hole and extend into the cleaning inclined tunnel and be implanted into the top plate of the cleaning inclined tunnel slope head and flat tunnel plugging section.

6. The method for sealing harmful gases in goaf by grouting in a three-dimensional intersection tunnel according to claim 1, characterized in that: In step D, the type of drilling holes also includes three types of drilling holes, and the first type of drilling holes, the second type of drilling holes and the third type of drilling holes are arranged in sequence. The third type of drilling holes does not penetrate the bottom plate of the cleaning inclined lane. The third type of drilling holes is used to implant short anchor cables in the top plate of the lower lane and the bottom plate of the cleaning inclined lane.

7. The method for sealing harmful gases in goaf by grouting in a three-dimensional intersection tunnel according to claim 1, characterized in that: The high-expansion fast-setting grouting material is a phenolic resin foaming material used for filling and sealing coal mines.

8. The method for sealing harmful gases in goafs by grouting in grade-separated cross tunnels according to claim 1, characterized in that: In step E, before grouting, monitoring points are set up at the downwind end of the air leakage point of the closed wall in the return air lane and at the downwind end of the three-dimensional intersection position in the lower lane. During grouting, the changes in the concentration of harmful gases are monitored online through the monitoring points, and the grouting parameters are adjusted in time according to the monitoring data.

9. The method for sealing harmful gases in goafs by grouting in grade-separated cross-tunnels according to claim 1, characterized in that: Also includes Step F: After the sealing wall is constructed, spray-sealed and repaired the air leakage points in the closed wall of the return air channel to block the air leakage.

10. The method for sealing harmful gases in goaf by grouting in a three-dimensional intersection tunnel according to claim 1, characterized in that: The upper section of the skeleton anchor cable (1) and the upper section of the grouting pipe (2) are sleeved with an elastic support member (3) whose front end is pressurized and can be deformed outwards. After being deformed outwards, the elastic support member (3) is used to act as a barrier grid for high-expansion fast-setting grouting materials. The elastic support member (3) comprises an upper sleeve (301) and a lower sleeve (302) distributed at an upper and lower intervals. A plurality of elastic support ribs (303) with a certain curvature are circumferentially connected between the lower end surface of the upper sleeve (301) and the upper end surface of the lower sleeve (302). The lower end of the lower sleeve (302) is connected with a locking ring (304). The outer surface of the locking ring (304) is an outer conical surface. The lower end of the locking ring (304) is provided with a plurality of axially penetrating cutouts (305). The locking ring (304) is also threadedly connected with a locking nut (306).

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