Method for plugging goaf harmful gas by three-dimensional intersection roadway grouting

Abstract

The present application relates to the technical field of coal mine roadway harmful gas plugging, in particular to a method for plugging gob harmful gas by grouting in three-dimensional crossing roadway, comprising the following steps: A: determining a three-dimensional crossing fresh air flow lower roadway at the air leakage point upwind; B: determining the position and boundary of the three-dimensional crossing in the lower roadway; C: building a drilling machine and grouting operation platform in the lower roadway; D: determining the drilling position and drilling spacing in the lower roadway, drilling each construction, the construction steps all include drilling-implanting-sealing, the drilling types include drilling type one and drilling type two, which are arranged at intervals, drilling type one is used for implanting skeleton anchor cable, and drilling type two is used for implanting grouting pipe; E: injecting high expansion fast setting grouting material into the grouting pipe in the lower roadway to build a plugging wall. The method has small ventilation negative pressure, small plugging construction engineering quantity, fast construction speed, good plugging compactness effect, and avoids frequent shift alternation operation, thereby ensuring the safety of construction personnel.

Description

Technical Field

[0001] This invention relates to the field of hazardous gas sealing technology in coal mine roadways, specifically a method for sealing hazardous gases in goaf areas by grouting in three-dimensional intersecting roadways. Background Technology

[0002] In coal mine ventilation, return airway plays a crucial role in expelling various harmful gases from the mine. When a return airway is located near a goaf, it is typically sealed with a closed wall to prevent harmful gases from overflowing into the return airway via a bypass. However, due to the high negative pressure in the return airway, the closed wall is significantly affected by mining pressure and is prone to deformation and cracking. Over time, the closed wall can leak air, allowing harmful gases (such as CO and CH4) from the goaf to easily enter the return airway through these leaks. This increases the concentration of harmful gases in the return airway, and if the concentration exceeds a certain level, it can endanger personal safety.

[0003] For this type of air leak, construction workers typically need to enter the return airway to the leak point and directly spray grout to seal the airtight wall, or drill holes in the airtight wall and inject grout through grouting pipes to reconstruct the windbreak wall and achieve filling and sealing. However, when the concentration of harmful gases in the return airway is high, the concentration of harmful gases at the corresponding return air leak point may even exceed 1000 ppm. When construction workers are working in the toxic and harmful gas return airflow, even with respirators and frequent shift changes, their safety is still threatened. At the same time, the negative pressure at the leak point is large, the spray grout sealing effect is poor, and the reconstruction of the sealing wall takes a long time. Therefore, the above treatment methods are difficult to meet the technical requirements for rapid sealing in complex and harsh environments. Summary of the Invention

[0004] The purpose of this invention is to provide a method for grouting and sealing harmful gases in goaf areas in three-dimensional intersecting roadways, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for grouting and sealing harmful gases in a goaf area in a three-dimensional intersecting roadway, comprising the following steps:

[0006] Step A: Determine a fresh airflow down passage that intersects the cleaning inclined passage at an angle with the air leakage point of the sealed wall upwind of the cleaning inclined passage;

[0007] Step B: Determine the location and boundary of the intersection between the lower roadway and the cleaning inclined roadway, and then determine the blocking section of the cleaning inclined roadway at the intersection location.

[0008] Step C: Construct a drilling rig and grouting platform in the lower tunnel;

[0009] 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;

[0010] 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 at the same time fill the separation layer cracks between the roof of the lower roadway and the floor of the cleaning inclined roadway.

[0011] 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 hole construction sequence is in the order of two-one-four-three-six-five, etc. After completing the construction of each drilling hole type two, the corresponding grouting pipe grouting operation is immediately implemented.

[0012] 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. In step D, the drilling hole construction 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.

[0013] Optionally, in step D, the drilling hole diameter is 26-30mm, and the drilling spacing is 1-1.3m. The drilling hole diameters of drilling hole type one and drilling hole type two are equal.

[0014] 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.

[0015] Optionally, in step D, the type of drilling hole also includes 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.

[0016] Optionally, the high-expansion fast-setting grouting material is a coal mine filling airtight phenolic resin foaming material.

[0017] 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.

[0018] Optionally, the method further comprises

[0019] 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.

[0020] 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 spaced vertically, a plurality of elastic support ribs with a certain curvature are connected between the lower end surface of the upper sleeve ring and the upper end surface of the lower sleeve ring in the 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.

[0021] Compared with the prior art, the present application has the following advantages:

[0022] 1. The present application is constructed in the lower roadway at the position of the upwind head of the cleaned inclined roadway and the three-dimensional intersection, and a sealing wall is constructed in the slope head flat roadway sealing section of the cleaned inclined roadway, the ventilation negative pressure at the construction position is small, the sealing construction engineering quantity is small, the construction speed is fast, the sealing effect is good, and frequent shift alternation operation is avoided, ensuring the safety of the construction personnel.

[0023] 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 in the slope head flat roadway sealing section of the cleaned inclined roadway, and preventing blowing and dumping under the action of negative pressure ventilation.

[0024] 3. The drilling construction sequence of the present application is in the order of two-one-four-three-six-five……, and 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

[0025] Figure 1A schematic diagram of roadway distribution and sealing for an embodiment of the present application;

[0026] Figure 2 A schematic diagram of roadway distribution and sealing for an embodiment of the present application; Figure 1 A cross-sectional view of the X-X portion;

[0027] Figure 3 A schematic diagram of the structure of the elastic support on the skeleton anchor cable in the present application;

[0028] Figure 4 A schematic diagram of the structure of the elastic support on the grouting pipe in the present application.

[0029] In the figure: 1, skeleton anchor cable; 2, grouting pipe; 3, elastic support; 301, upper collar; 302, lower collar; 303, elastic support rib; 304, locking ring; 305, cross-sectional slit; 306, locking nut. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0031] Please refer to Figure 1 and Figure 2 , which are schematic diagrams of roadway distribution and sealing in a certain area actually surveyed. Through monitoring, the CO concentration of the return air flow in the return air roadway exceeds 90PPm, and the air leakage at the two airtight walls in the return air roadway is serious. The on-site measured CO concentration at the two air leakage points exceeds 1000PPm. The monitoring data shows that the CO concentration has a gradual upward trend in the last three days, which poses a significant threat to the safety production of the coal mine.

[0032] 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 middle height = 3.0m x 2.5m; the lower roadway is located in the coal floor, and the width x middle height = 4.5m x 3.5m. The CO concentration in the return air flow of the return air roadway is not more than 24PPm (the value specified in the coal mine safety regulations) through the following sealing method, which creates good working conditions for ensuring the safety of mine ventilation, and the technical and economic benefits are very significant. The sealing method will be described,

[0033] The embodiment of the present application provides a method for sealing gob harmful gas by grouting in a three-dimensional intersection roadway, which comprises the following steps:

[0034] 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;

[0035] Step B: determine the position and boundary of the intersection with the cleaning inclined roadway in the lower roadway, and then determine the sealing section of the cleaning inclined roadway slope tunnel in the intersection position;

[0036] Step C: build a drilling machine in the lower roadway at the intersection position, and build a grouting operation platform 15m away from the upper wind head of the intersection position;

[0037] Step D: determine the drilling position, drilling diameter, drilling depth and drilling spacing along the full section of the sealing section of the cleaning inclined roadway slope tunnel within the boundary of the intersection in the lower roadway, drill each hole, and each drilling step includes drilling-hole-implantation-hole sealing, wherein the drilling types include drilling type one and drilling type two, drilling type one and drilling type two are arranged alternately, drilling type one is used to implant skeletal anchor cable 1 in the sealing section of the cleaning inclined roadway slope tunnel, and drilling type two is used to implant grouting pipe 2 in the sealing section of the cleaning inclined roadway slope tunnel, the skeletal anchor cable 1 and the grouting pipe 2 together play the role of blocking the grid;

[0038] Step E: inject high-expansion fast-setting grouting material into the grouting pipe 2 implanted in the sealing section of the cleaning inclined roadway slope tunnel in the lower roadway to build a sealing wall, and at the same time fill the separation layer cracks between the lower roadway roof and the cleaning inclined roadway floor;

[0039] 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.

[0040] When the skeletal anchor cable 1 is penetrated through the lower roadway roof and the cleaning inclined roadway floor and enters the cleaning inclined roadway, CO in the overlying intersection roadway will flow into the lower roadway along the drilling and separation layer cracks under the action of ventilation negative pressure. In step D of the embodiment, the drilling is sorted in order, the serial numbers one, three, five, … are drilling type two, and the serial numbers two, four, six, … are drilling type one, and the drilling sequence is two-one-four-three-six-five, …, after completing the construction of each drilling type two, the corresponding grouting pipe 2 is immediately implemented, which can reduce the harmful gas leakage amount of the separation layer cracks during the grouting process, reduce the external overflow concentration of harmful gas in the lower roadway, and thus ensure the safety of the construction personnel.

[0041] On the basis of the above embodiment, in step D, the drilling sequence direction is along the downwind flow direction of the lower roadway, and starts from the side deviated to the upper wind head of the sealing section of the cleaning inclined roadway slope tunnel. The drilling diameter is 26-30mm, and in this embodiment, the drilling diameters of drilling type one and drilling type two are both 28mm, the drilling spacing is 1-1.3m, the drilling diameters of drilling type one and drilling type two are equal, which is convenient for construction and emergency mutual use, and provides work efficiency. According to the interlayer spacing and the cleaning inclined roadway layer height, the size of the skeletal anchor cable 1 is Φ22mm×6-7m.

[0042] 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 from far away, 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 in the sealing section of the cleaning inclined roadway at the slope head, which can enhance the overall compressive strength of the filling body in the sealing section of the cleaning inclined roadway at the slope head, and prevent blowing and dumping under the action of negative pressure ventilation.

[0043] On the basis of the above-mentioned embodiments, 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.

[0044] In this embodiment, the high-expansion fast-setting grouting material is a coal mine filling airtight 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 and 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.

[0045] On the basis of the above-mentioned embodiments, in step E, monitoring points are set at the downwind head of the air return roadway at the air leakage point of the airtight 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.

[0046] 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 threadedly connected outside the locking ring 304. When the locking nut 306 is loosened, the sleeving 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.

[0047] 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 plugging goaf harmful gas by three-dimensional intersection roadway grouting, characterized in that, The method comprises the following steps: Step A: determining a fresh air down tunnel intersecting with the cleaning inclined tunnel at the stereoscopic intersection of the cleaning inclined tunnel; Step B: determining the position and boundary of the down tunnel intersecting with the cleaning inclined tunnel, and further determining the cleaning inclined tunnel slope head flat roadway sealing section of the cleaning inclined tunnel at the stereoscopic intersection position; Step C: building a drilling machine and grouting operation platform in the down tunnel; Step D: determining the drilling position, drilling diameter, drilling depth and drilling spacing along the full section of the cleaning inclined tunnel slope head flat roadway sealing section within the boundary of the stereoscopic intersection in the down tunnel, drilling each drilling hole, and each drilling hole comprises the steps of drilling, implanting and sealing, wherein the drilling types comprise drilling type I and drilling type II, the drilling type I and the drilling type II are arranged at intervals, the drilling type I is used for implanting a skeleton anchor cable (1) in the cleaning inclined tunnel slope head flat roadway sealing section, the drilling type II is used for implanting a grouting pipe (2) in the cleaning inclined tunnel slope head flat roadway sealing section, and the skeleton anchor cable (1) and the grouting pipe (2) together play the role of blocking the grid; Step E: injecting high-expansion fast-setting grouting material into the grouting pipe (2) implanted in the cleaning inclined tunnel slope head flat roadway sealing section in the down tunnel to build a sealing wall, and filling the separation layer cracks between the down tunnel roof and the cleaning inclined tunnel floor.

2. The method for plugging goaf harmful gas by three-dimensional intersection roadway grouting according to claim 1, characterized in that, In step D, the drilling holes are sorted in sequence, the sequence numbers I, III, V, … are the drilling type II, the sequence numbers II, IV, VI, … are the drilling type I, and the drilling sequence is according to the sequence numbers II-I-IV-III-VI-…, after completing the construction of each drilling type II, the corresponding grouting pipe (2) is immediately implemented.

3. The method according to claim 1, wherein, In step C, the drilling machine and grouting operation platform are built at the upwind head 15 m away from the stereoscopic intersection position in the down tunnel; in step D, the drilling sequence direction is along the upwind flow direction of the down tunnel, and the drilling sequence starts from the side deviated from the upwind head of the cleaning inclined tunnel slope head flat roadway sealing section.

4. The method for plugging goaf harmful gas by three-dimensional intersection roadway grouting according to claim 1, characterized in that, In step D, the drilling diameter is 26-30 mm, and the drilling spacing is 1-1.3 m; the drilling diameters of the drilling type I and the drilling type II are equal.

5. The method for plugging goaf harmful gas by three-dimensional intersection roadway grouting according to claim 4, characterized in that, In step D, the drilling type I and the drilling type II both penetrate the cleaning inclined tunnel floor, the skeleton anchor cable (1) extends into the cleaning inclined tunnel through the drilling type I and is implanted into the cleaning inclined tunnel slope head flat roadway sealing section roof, and the grouting pipe (2) extends into the cleaning inclined tunnel through the drilling type II and is implanted into the cleaning inclined tunnel slope head flat roadway sealing section roof.

6. The method for plugging goaf harmful gas by three-dimensional intersection roadway grouting according to claim 1, characterized in that, In step D, the drilling types further comprise drilling type III, the drilling type I, the drilling type II and the drilling type III are arranged at intervals, the drilling type III does not penetrate the cleaning inclined tunnel floor, and the drilling type III is used for implanting a short anchor cable in the down tunnel roof and the cleaning inclined tunnel floor.

7. The method according to claim 1, wherein, The high-expansion fast-setting grouting material is a coal mine filling sealing phenolic resin foaming material.

8. The method for plugging goaf harmful gas by three-dimensional intersection roadway grouting according to claim 1, characterized in that, In step E, monitoring points are arranged at the downwind head of the air return tunnel at the sealing wall air leakage point and the downwind head of the down tunnel at the stereoscopic intersection position before grouting, the harmful gas concentration changes are monitored online through the monitoring points during grouting, and the grouting parameters are adjusted in time according to the monitoring data.

9. The method according to claim 1, wherein, Further comprising Step F: after the sealing wall is built, the air return tunnel at the sealing wall air leakage point is treated by spraying and sealing to block the air leakage.

10. The method for plugging goaf harmful gas by three-dimensional intersection roadway grouting 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 (3) which can expand outward under pressure at the front end, and the elastic support (3) is used for playing a role of blocking grid to high-expansion fast-setting grouting material after outward expansion deformation; the elastic support (3) comprises upper and lower sleeves (301) and (302) which are distributed with an upper and lower spacing, a plurality of elastic support ribs (303) with a certain arc are connected in a 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 formed in the lower end of the locking ring (304), and the locking ring (304) is further threadedly connected with a locking nut (306) outside.

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