Water injection reaction expansion rock breaking cartridge capable of being retained in drill hole

Abstract

The water injection reaction expansion rock breaking cartridge capable of being retained in the drill hole comprises a plurality of sections of charging barrels which are sequentially connected end to end in the vertical direction, a water passing pipe is coaxially arranged in each charging barrel, and a plurality of first water permeable small holes communicated with the interior of each charging barrel are formed in each water passing pipe. The upper end and the lower end of the water pipe are both provided with connecting pieces used for pressing all the series-connection powder charging barrels, and the upper end of the water pipe is provided with a guide head in butt joint with the upper end of the uppermost powder charging barrel. The device can be installed in a drill hole in advance, the working procedure that grouting equipment is called for mixing and stirring on a construction site is avoided, the construction efficiency and the construction safety are improved, and meanwhile the opportunity for cracking coal and rock masses can be selected more flexibly. The retention type cartridge does not react after being loaded into the drill hole and can remain in the drill hole for a long time, water is injected into the drill hole through the water injection pipe when coal and rock mass needs to be fractured, and the use convenience degree of the static fracturing technology is further improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of coal mine safety production, and particularly relates to a water injection reaction expansion rock-breaking cartridge that can be retained in a borehole. Background Technique

[0002] When a coal seam with a hard and difficult-to-collapse roof is mined by a longwall working face, a large area of suspended roof is likely to form in the goaf. After the suspended roof exceeds the limit area, the large-area roof will collapse in a very short time, which will seriously affect the safety production of the working face. The basic principle of preventing and controlling large-scale roof weighting and collapse is to take effective measures to prevent the suspended roof in the goaf from being too large. The main method is to pre-crack the roadway roof, the working face roof or the top coal in advance. When pre-cracking, roof boreholes are constructed and then the roof or top coal is pre-cracked by blasting, bursting agent, hydraulic or mechanical means. Since the static bursting agent is safe, convenient, free of harmful gases, vibration-free and has a long-lasting acting time, it is an ideal roof pre-cracking method. Under the influence of factors such as limited borehole space and surrounding rock constraints, the static bursting agent relies on its own long-term stable reaction to continuously weaken the roof rock layer through expansion stress, causing tensile failure inside the rock layer and inducing the generation and expansion of internal cracks until they penetrate to form macroscopic cracks, so as to achieve the purpose of weakening and cracking the coal seam roof.

[0003] At present, there are mainly four methods for cracking the roof underground. One is to use carbon dioxide cracking technology. By using the principle that carbon dioxide changes from liquid to gas and expands in volume after heating, the roof is cracked. However, this technology is only applicable to relatively intact roofs, and its application range is relatively small. There are problems such as the storage, transportation and application of carbon dioxide being too inconvenient, and the excessive carbon dioxide content will cause certain dangers and affect the safety production of coal mines underground.

[0004] The second is the hydraulic fracturing technology, which injects high-pressure water into the borehole to fracture the roof rock in sections and destroy its integrity. It is widely used, but there are problems such as the need for large equipment, poor artificial control of the fracturing effect, low construction efficiency, general rock-breaking efficiency, and affecting normal production.

[0005] The third is the pre-splitting blasting technology, which forms cracks by pre-performing deep-hole blasting on the roof in the working face gate road. As the working face is mined, the roof will collapse by itself. It is currently the roof cracking technology with the widest application range and the best effect, but there are problems such as high cost, open fire, a large amount of dust, a large damaged area, easy to cause engineering geological disasters, high danger, low energy utilization rate, strict safety in the storage and transportation of explosive materials and strict control of explosive materials, and affecting normal production.

[0006] Fourthly, a static crushing agent slurry is injected into the borehole by using a grouting pump, and the roof rock is fractured by the expansion pressure. As the working face is mined, the top coal in the roadway collapses, and the collapse range gradually expands, with the free face continuously increasing, and the roof collapses. However, for mines with large production capacity, the construction process of injecting the expansion agent slurry by using a grouting pump is relatively complex, which affects the construction progress and is difficult to be popularized and used on site. In view of the above problems, a technology of using a series-connected self-expanding tube filled with a crushing agent to fracture the roof is studied. This technology has the advantages of low cost, high effect and small safety risk. Utility Model Content

[0007] To solve the above technical problems, the utility model provides a water injection reaction expansion rock-breaking cartridge that can be retained in the borehole, which has a simple structure, is convenient to operate, is safe and reliable, has a low cost, and has a good rock-breaking effect.

[0008] To solve the above technical problems, the utility model adopts the following technical scheme: A water injection reaction expansion rock-breaking cartridge that can be retained in the borehole includes a plurality of charging cartridges connected end to end in sequence along the vertical direction. A water pipe is coaxially arranged inside the charging cartridge. A plurality of first water-permeable small holes that are all communicated with the inside of the charging cartridge are opened on the water pipe. Connecting pieces for pressing all the series-connected charging cartridges are arranged at both the upper and lower ends of the water pipe. A guiding head for docking with the upper end of the uppermost charging cartridge is arranged at the upper end of the water pipe. A plug for docking with the lower end of the lowermost charging cartridge is arranged at the lower end of the water pipe. Through holes communicated with the water pipe are opened at the centers of the guiding head and the plug.

[0009] The upper end part of the guiding head is a conical surface that is thinner at the top and thicker at the bottom. The outer circle of the lower end part of the plug is a conical surface that is thinner at the bottom and thicker at the top. A through-long sealing rubber sleeve is arranged outside the guiding head, all the charging cartridges and the plug. The upper port of the sealing rubber sleeve is heat-shrunk and wrapped around the conical surface at the upper end of the guiding head. The lower port of the sealing rubber sleeve is heat-shrunk and wrapped around the conical surface at the lower end of the plug.

[0010] The charging cartridge includes an outer cylinder body and an inner cylinder body arranged concentrically. A fixed end cover provided with a central hole is fixedly arranged at one port of the outer cylinder body. One end of the inner cylinder body is fixedly connected to the inner surface of the fixed end cover. A plurality of second water-permeable small holes are opened on the inner cylinder body. Removable movable end covers are arranged at the other ends of the outer cylinder body and the inner cylinder body. A static blasting expansion powder is filled in the annular cavity formed between the inner circle of the outer cylinder body and the outer circle of the inner cylinder body. The water pipe axially passes through the fixed end cover, the inner cylinder body and the movable end cover, and the outer circle of the water pipe is in clearance fit with the inner circle of the inner cylinder body.

[0011] The water pipe adopts a threaded pipe. The connecting piece includes a fastening nut and a backing plate. The backing plate is sleeved on the water pipe, and the fastening nut is threadedly connected to the threaded pipe and presses the backing plate against the end of the charging cartridge.

[0012] The through holes opened at the centers of the guiding head and the plug include an inner hexagonal hole sleeved outside the fastening nut and a round hole docked with the port of the water pipe. A temporary sealing cover is arranged in the round hole.

[0013] Two anti-slip steel sheets are fixedly arranged on the outer circle of the guide head. The two anti-slip steel sheets are symmetrically arranged with respect to the center line of the guide head. Both anti-slip steel sheets extend out of the sealing rubber sleeve. The upper end of the anti-slip steel sheet is fixedly connected to the outer circle of the guide head. The included angle between the length direction of the anti-slip steel sheet and the center line of the guide head is an acute angle.

[0014] Adopting the above technical solution, the utility model has significant progress as follows:

[0015] (1) The cartridge structure is simple. It is a fully enclosed cartridge, which can be directly inserted into the drill hole in the roof. When inserted into the drill hole, the two anti-slip steel sheets are compressed under their own elasticity and move upward along the drill hole. After the cartridge is installed in place, the anti-slip steel sheets unfold, and the lower ends of the anti-slip steel sheets are inserted into the inner wall of the drill hole, which can ensure that the cartridge will not slide down.

[0016] (2) Easy to assemble. During use, only multiple cartridges need to be respectively connected to the water pipe ports through connecting straight-throughs and then inserted into the drill hole. When sealing the orifice of the drill hole, a water injection pipe needs to be reserved. The upper end of the water injection pipe is connected to the lower port of the water pipe in the lowermost cartridge. When reaction and cracking are required, water is injected into the drill hole through the water injection pipe.

[0017] (3) Low manufacturing cost. The price of the static blasting expansion powder is low, and other materials such as pipes, plates, nuts, etc. are also easily available.

[0018] (4) Convenient transportation. The expansion rock-breaking cartridge is small in volume and light in weight, and can be carried by a single coal miner.

[0019] (5) High safety. The static blasting expansion powder is compacted and loaded into the charging cylinder according to a certain density. The cartridge is a fully sealed structure during storage and transportation. After being inserted into the drill hole, it can be retained for use, avoiding direct contact between workers and the agent, and improving the construction safety.

[0020] (6) Improved efficiency. By pre-loading the static blasting expansion powder into the charging cylinder to form a structure that can stay in the drill hole for a period of time, when expansion rock-breaking is required, water is injected. The static blasting expansion powder reacts by absorbing water. According to the engineering situation, it is convenient to inject water into the drill hole with the cartridge installed to cause cracking. The sealed cartridge structure can prevent the cartridge from reacting in advance due to humidity and water spraying in the drill hole, simplifying the construction steps and saving construction time.

[0021] (7) Cost saving. The dosage of the expansion rock-breaking cartridge can be dynamically changed according to conditions such as the distribution of coal seam lithology, on-site construction, and production progress.

[0022] In summary, the utility model uses an expansion rock-breaking cartridge that can be retained in a drill hole. The expansion rock-breaking cartridge filled with static blasting expansion powder can be loaded into the drill hole in advance, avoiding the process of mixing and stirring on the construction site by using grouting equipment, improving the construction efficiency and construction safety, and at the same time being able to more flexibly select the timing of fracturing coal and rock masses. After the retention-type cartridge is loaded into the drill hole, it does not react and can be retained in the drill hole for a long time. When it is necessary to fracture coal and rock masses, water can be injected into the drill hole through a water injection pipe, further improving the convenience of using the static fracturing technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of the explosion structure of the utility model;

[0024] Figure 2 is a schematic diagram of two adjacent units of the utility model connected by a connecting straight-through;

[0025] Figure 3 is a schematic diagram of the utility model installed in a drill hole and sealed at the hole mouth;

[0026] Figure 4 is Figure 1 the enlarged view of part A in

[0027] Figure 5 is Figure 1 the enlarged view of part B in

[0028] Figure 6 is Figure 1 the enlarged view of the plug in DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] The following further describes in detail the embodiments of the utility model with reference to the drawings and embodiments.

[0030] As Figures 1-6 shown, a water injection reaction expansion rock-breaking cartridge that can be retained in a drill hole of the utility model includes a plurality of (three) charging cartridges 1 connected end to end in sequence along the vertical direction. A water pipe 2 is coaxially arranged inside the charging cartridge 1. A plurality of first water-permeable small holes 3 that are all communicated with the inside of the charging cartridge 1 are opened on the water pipe 2. Connecting pieces for pressing all the series-connected charging cartridges 1 are arranged at both the upper and lower ends of the water pipe 2. A guiding head 4 that is butted against the upper end of the uppermost charging cartridge 1 is arranged at the upper end of the water pipe 2. A plug 5 that is butted against the lower end of the lowermost charging cartridge 1 is arranged at the lower end of the water pipe 2. Through holes communicated with the water pipe 2 are opened at the centers of the guiding head 4 and the plug 5.

[0031] The upper end of the guide head 4 is a conical surface that is thin at the top and thick at the bottom, and the outer circle of the lower end of the plug 5 is a conical surface that is thin at the bottom and thick at the top. A full-length sealing rubber sleeve 6 is provided on the outside of the guide head 4, all the sectioned drug cartridges 1 and the plug 5. The upper end of the sealing rubber sleeve 6 is heat-shrunk and wrapped around the conical surface of the upper end of the guide head 4, and the lower end of the sealing rubber sleeve 6 is heat-shrunk and wrapped around the conical surface of the lower end of the plug 5, so that the guide head 4, the plug 5 and the drug cartridge 1 are connected as a whole in the axial direction.

[0032] The drug-loading cartridge 1 comprises an outer cylinder 7 and an inner cylinder 8 which are arranged cocentrically, a fixed end cover 9 with a center hole being fixedly provided at one end of the outer cylinder 7, one end of the inner cylinder 8 is fixedly connected to the inner surface of the fixed end cover 9, a plurality of second water-permeable holes 10 are provided on the inner cylinder 8, a detachable movable end cover 11 is provided at the other ends of the outer cylinder 7 and the inner cylinder 8, the annular cavity formed between the inner circle of the outer cylinder 7 and the outer circle of the inner cylinder 8 is filled with static blasting expansion powder (not shown), the water pipe 2 coaxially passes through the fixed end cover 9, the inner cylinder 8 and the movable end cover 11, and the outer circle of the water pipe 2 is clearance-matched with the inner circle of the inner cylinder 8.

[0033] The water pipe 2 is a threaded pipe, and the connecting piece includes a fastening nut 12 and a gasket 13. The gasket 13 is sleeved on the water pipe 2. The fastening nut 12 is threadedly connected to the threaded pipe and presses the gasket 13 against the end of the drug cartridge 1.

[0034] The through holes formed in the center of the guide head 4 and the plug 5 include an inner hexagonal hole 14 sleeved on the outside of the fastening nut 12 and a circular hole 15 connected to the end of the water pipe 2, and a temporary sealing cover 16 is provided in the circular hole 15.

[0035] Two anti-skid steel sheets 17 are fixedly provided on the outer circle of the guide head 4. The two anti-skid steel sheets 17 are symmetrically arranged about the center line of the guide head 4. The two anti-skid steel sheets 17 both extend out of the sealing rubber sleeve 6. The upper ends of the anti-skid steel sheets 17 are fixedly connected to the outer circle of the guide head 4. The length direction of the anti-skid steel sheets 17 and the center line of the guide head 4 are at an acute angle.

[0036] The charging cartridge 1 is filled with static blasting expansion powder at a certain compaction density. The centers of 3 - 4 charging cartridges 1 are strung together by a water - passing pipe 2. A number of first water - permeable small holes 3 and second water - permeable small holes 10 are respectively opened on the water - passing pipe 2 and the inner cylinder 8, which are used for water to enter the charging cartridge 1 when injecting water so that the static blasting expansion powder absorbs water. The sealing rubber sleeve 6 plays a role in preventing the whole expansion rock - breaking cartridge from getting wet and water - logged in the drill hole 19 after being inserted, which may cause the cartridge to react in advance. When the static blasting expansion powder needs to react, water is injected into the water - passing pipe 2, and the static blasting expansion powder absorbs water and starts to react and expand. Gaskets 13 are arranged at both ends and axially positioned by fastening nuts 12, which are used to axially restrain the expansion deformation of the cartridge. The temporary sealing caps 16 are installed at the center holes at both ends of the cartridge to prevent the cartridge from absorbing water and reacting during transportation and storage. When inserting into the drill hole 19, the temporary sealing caps 16 need to be removed. The upper end of the guiding head 4 is a conical surface (guide angle structure) that is thinner at the top and thicker at the bottom, which is beneficial for pushing the cartridge into the drill hole 19. The anti - slip steel sheets 17 are installed on both sides of the guiding head 4, which can ensure that the cartridge will not slide down when the cartridge is installed in the upward - angled drill hole 19.

[0037] When the cartridge needs to be installed into the drill hole 19, the temporary sealing caps 16 at the centers of the guiding head 4 and the plug 5 of the cartridge need to be removed. The connecting straight - through 18 is used to connect between two cartridges. The connecting straight - through 18 can be inserted into the inner holes at both ends of the water - passing pipe 2 to ensure that the connection gap between two cartridges does not leak water when injecting water.

[0038] After the construction of the drill hole 19 is completed, the cartridges are inserted into the drill hole 19 one by one, and adjacent cartridges are connected by the connecting straight - through 18. The hole opening of the drill hole 19 is sealed with a sealing material. The sealing section 21 is not less than 0.5 m. The sealing material should have a certain cementing ability and expansibility to ensure that the drill hole 19 does not leak water when injecting water. When sealing, a water injection pipe is reserved. The inner end of the water injection pipe is inserted into the inner hole of the water - passing pipe 2 of the lowermost cartridge, and the outer end is reserved outside the drill hole 19 for connecting the water injection pipeline.

[0039] When in the drill hole 19 such as Figure 3After the cartridge, hole plugging, and the reserved water injection pipe 20 are completed as shown, all installation work is finished. The cartridge can remain in the drill hole 19, at this time the static blasting expansion powder does not react and does not expand. When it is necessary to fracture the roof with the drill hole 19, connect the water injection pipeline to the reserved water injection pipe 20 at the orifice of the drill hole 19 and conduct water injection. The water injection pressure exceeds the water pressure difference generated by the height of the drill hole 19, and the water injection time is not less than 30 minutes. After the static blasting expansion powder encounters water, it starts to absorb water and react. After 1 hour, it starts to slowly expand radially. After 8 hours, the expansion pressure exceeds 16 MPa. After 24 hours, the expansion pressure exceeds 38 MPa. The cartridge has a long expansion time, and there are no vibrations, harmful gases, or blasting waves during the expansion period, and it is very safe to use. Under the influence of factors such as the limited space of the drill hole 19 and the restriction of the surrounding rock, the static blasting expansion powder relies on its own long-term stable reaction, continuously weakens the roof rock layer through the expansion stress, causes tensile failure inside the rock layer and induces the generation and expansion of internal cracks until they penetrate to form macroscopic cracks, achieving the purpose of weakening and fracturing the coal seam roof.

[0040] The above embodiments illustrate the basic principles and characteristics of the present invention. However, the above only illustrates the preferred embodiments of the present invention and is not limited by the described embodiments. Those of ordinary skill in the art, inspired by this patent, without departing from the purpose of the present invention and the scope protected by the claims, can also make many forms of deformation and improvement, and these all fall within the protection scope of the present invention. Therefore, the patent and protection scope of the present invention should be subject to the appended claims.

Claims

1. A water injection reaction expansion rock breaking cartridge that can be retained in a borehole, characterized in that: The utility model comprises a plurality of drug-loading cartridges connected in sequence along the vertical direction, a water pipe is coaxially arranged inside the drug-loading cartridge, a plurality of first water-permeable holes are opened on the water pipe, all of which are connected with the inside of the drug-loading cartridge, the upper and lower ends of the water pipe are provided with connectors for pressing all the drug-loading cartridges connected in series, the upper end of the water pipe is provided with a guide head connected with the upper end of the uppermost drug-loading cartridge, the lower end of the water pipe is provided with a plug connected with the lower end of the lowermost drug-loading cartridge, and the centers of the guide head and the plug are provided with through holes connected with the water pipe.

2. The water injection reaction expansion rock breaking cartridge that can be retained in a borehole according to claim 1, characterized in that: The upper end of the guide head is a conical surface that is thin at the top and thick at the bottom, and the outer circle of the lower end of the plug is a conical surface that is thin at the bottom and thick at the top. A full-length sealing rubber sleeve is provided on the outside of the guide head, all segmented cartridges and the plug. The upper end of the sealing rubber sleeve is wrapped around the conical surface of the upper end of the guide head after heat shrinkage, and the lower end of the sealing rubber sleeve is wrapped around the conical surface of the lower end of the plug after heat shrinkage.

3. A water injection reaction expansion rock breaking cartridge capable of being retained in a borehole according to claim 1 or 2, characterized in that: The charge cartridge comprises an outer cylinder and an inner cylinder which are arranged coaxially, a fixed end cover with a center hole being fixedly provided at one end of the outer cylinder, one end of the inner cylinder is fixedly connected to the inner surface of the fixed end cover, a plurality of second water-permeable holes are provided on the inner cylinder, and a detachable movable end cover is provided at the other end of the outer cylinder and the inner cylinder, and a static blasting expansion powder is filled in the annular cavity formed between the inner circle of the outer cylinder and the outer circle of the inner cylinder, and a water pipe coaxially passes through the fixed end cover, the inner cylinder and the movable end cover, and the outer circle of the water pipe is clearance-matched with the inner circle of the inner cylinder.

4. A water injection reaction expansion rock breaking cartridge capable of being retained in a borehole according to claim 1 or 2, characterized in that: The water pipe adopts a threaded pipe, and the connecting parts include a fastening nut and a pad. The pad is sleeved on the water pipe, and the fastening nut is threadedly connected to the threaded pipe and presses the pad tightly to the end of the cartridge.

5. The water injection reaction expansion rock breaking cartridge that can be retained in a borehole according to claim 4, characterized in that: The through holes opened in the center of the guide head and the plug include an inner hexagonal hole sleeved on the outside of the fastening nut and a round hole butted against the port of the water pipe, and a temporary sealing cover is arranged in the round hole.

6. The water injection reaction expansion rock breaking cartridge capable of being retained in a borehole according to claim 2, characterized in that: Two anti-slip steel sheets are fixedly provided on the outer circle of the guide head. The two anti-slip steel sheets are symmetrically arranged about the center line of the guide head. Both anti-slip steel sheets extend out of the sealing rubber sleeve. The upper ends of the anti-slip steel sheets are fixedly connected to the outer circle of the guide head. The length direction of the anti-slip steel sheets forms an acute angle with the center line of the guide head.

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