Underground engineering nanometer expansion fracturing capsule device

Abstract

According to the underground engineering nanometer expansion fracturing capsule device, a pressing and plugging pipe and a fracturing pipe penetrate through a plugging bag in a spaced mode, and the pressing and plugging pipe is communicated with an inner cavity of the plugging bag through a water outlet hole; the positioning mechanism is sleeved outside the lower end of the pressing and plugging pipe and synchronously acts with the plugging bag; the upper end of the bottom cylinder is fixedly connected with the lower end of the pressing and plugging pipe; the piston is assembled in an inner cavity of the bottom cylinder; the piston rod is assembled in the guide ring, and the upper end is fixedly connected with the piston; the baffle is fixedly connected to the lower end of the piston rod; the annular limiting plate fixedly sleeves the outer side of the bottom cylinder; the spring sleeves the bottom cylinder, and the upper end and the lower end of the spring abut against the annular limiting plate and the baffle correspondingly; the telescopic liquid injection pipe comprises an inner connecting pipe and an outer injection pressure pipe; the inner connecting pipe is fixedly supported on one side of the bottom cylinder, and the upper end of the inner connecting pipe is connected with the lower end of the fracturing pipe; the outer injection pipe is axially sleeved outside the inner connecting pipe in a sliding manner, and the lower end of the outer injection pipe is fixedly inserted into the mounting hole in the baffle plate. The device can obviously improve the fracturing effect and the construction efficiency.

Description

Technical Field

[0001] This invention belongs to the field of underground engineering expansion-induced cracking technology, specifically relating to an underground engineering nano-expansion-induced cracking capsule device. Background Technology

[0002] In the field of underground engineering construction, such as mining, tunnel excavation, and urban underground space development, traditional blasting methods have many drawbacks. On the one hand, the strong vibrations and shock waves generated by traditional blasting techniques can cause significant damage to the surrounding rock mass, easily leading to safety accidents such as rock instability and collapse, threatening the lives of construction workers, and also affecting the long-term stability of underground projects. On the other hand, traditional blasting techniques generate significant noise and dust pollution, which can easily cause serious damage to the surrounding environment and does not conform to the current green and environmentally friendly construction concepts.

[0003] While existing static fracturing techniques have addressed some of the drawbacks of traditional blasting, practical applications still suffer from issues such as inadequate borehole sealing, lack of protective buffering mechanisms, and the susceptibility of the sealing body to significant slippage due to impact forces. These issues significantly reduce fracturing effectiveness. Before static fracturing of rock mass through the reaction of chemical powders or liquids with high-pressure water to generate gas, inadequate borehole sealing can lead to gas leakage, hindering rapid pressurization within the borehole and thus affecting fracturing efficiency, reducing construction costs, and extending the construction period. Furthermore, inadequate positioning is a major cause of poor sealing. Traditional sealing devices often lack protective buffering mechanisms. During the fracturing pressurization process, the generated pressure and shock waves directly act on the sealing body. With inadequate positioning, the impact force can directly push the sealing body outwards, significantly reducing pressure in the fracturing zone and resulting in unsatisfactory fracturing results. To address the above deficiencies, there is an urgent need to provide a nano-expansion fracturing capsule device for underground engineering, which can achieve multiple improvements in sealing effect, protective buffering effect and positioning effect, and ultimately effectively ensure fracturing effect and construction efficiency. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a nano-expansion fracturing capsule device for underground engineering. This device has a reasonable structure and simultaneously possesses sealing, positioning, and protective buffering functions. It can simultaneously achieve reliable sealing of the borehole, reliable positioning within the borehole, and effective buffering of shock waves, which can significantly improve the fracturing effect and construction efficiency, while reducing the fracturing construction cost.

[0005] To achieve the above objectives, the present invention provides a nano-expansion fracturing capsule device for underground engineering, comprising a sealing and positioning unit and a buffer protection unit; The sealing and positioning unit includes a sealing mechanism and a positioning mechanism; the sealing mechanism includes a sealing bladder, a pressure plugging tube, and a fracturing tube; the pressure plugging tube is inserted into the sealing bladder in the vertical direction, and the pressure plugging tube has multiple liquid outlet holes in the portion of the sealing bladder cavity; the fracturing tube is distributed alternately with the pressure plugging tube and is inserted into the sealing bladder in the vertical direction; the positioning mechanism is located below the sealing bladder and is fixedly connected to the outer side of the lower part of the pressure plugging tube. The positioning mechanism moves synchronously with the sealing bladder. When the sealing bladder expands, the positioning mechanism extends radially and is radially positioned by pressing against the rock wall. When the sealing bladder retracts, the positioning mechanism retracts radially. The buffer protection unit includes a damping support and a telescopic injection tube; the damping support includes a bottom cylinder, a piston, a piston rod, a baffle, an annular limiting plate, and a spring; the upper end of the bottom cylinder is fixedly connected to the lower end of the pressure plugging tube, and a guide ring is fixedly connected to the inner side of its lower end; the piston is slidably and sealingly assembled in the inner cavity of the bottom cylinder; the piston rod is slidably assembled inside the guide ring, and its upper end is fixedly connected to the piston; the size of the baffle is adapted to the size of the drill hole, and it is fixedly connected to the lower end of the piston rod; the annular limiting plate is fixedly fitted on the outer side of the bottom cylinder; the spring is sleeved on the outside of the bottom cylinder, and its upper and lower ends abut against the annular limiting plate and the baffle, respectively; the telescopic injection tube includes an inner connecting tube and an outer injection tube; the inner connecting tube is fixedly supported on one side of the bottom cylinder, and its upper end is connected to the lower end of the fracturing tube; the outer injection tube is axially slidably fitted on the outside of the inner connecting tube, and its lower end is fixedly inserted into the mounting hole on the baffle.

[0006] In this invention, a pressure plugging tube is installed throughout the occlusion bladder, and multiple liquid outlet holes are provided on the tube. This facilitates the injection of high-pressure gas or high-pressure liquid into the occlusion bladder via the pressure plugging tube, enabling control of its expansion or contraction. Furthermore, when the positioning mechanism requires pneumatic or hydraulic actuation, the pressure plugging tube provides the necessary pneumatic or hydraulic power, facilitating synchronized drive control between the positioning mechanism and the occlusion bladder. Additionally, when the lower end of the pressure plugging tube connects to the bottom cylinder of the damping support, it also allows for the synchronous supply of high-pressure gas or high-pressure liquid to the damping support, enabling pneumatic or hydraulic actuation of the damping support to reach its maximum extension. A positioning mechanism is installed below the plugging bladder, and its operation is synchronized with that of the plugging bladder. This allows for reliable positioning within the borehole while the plugging bladder seals the borehole, preventing slippage of the plugging material. Especially during fracturing operations, the positioning mechanism effectively counteracts the impact force, ensuring reliable, targeted plugging and guaranteeing the fracturing effect. Furthermore, this synchronized mechanism allows the positioning mechanism to retract synchronously with the retraction of the plugging bladder, facilitating overall recovery and reuse. In the damping support, a piston is slidably sealed in the bottom cylinder, and the bottom cylinder is connected to the plugging pipe. Thus, when the plugging bladder expands, high-pressure gas or high-pressure liquid will enter the bottom cylinder simultaneously and drive the piston to extend the piston rod outward until the maximum stroke is reached. This will drive the baffle installed at the end of the piston rod to extend towards the bottom of the hole. The guide ring at the lower end of the bottom cylinder not only guides the piston rod during its movement but also limits the piston's stroke. The baffle fixedly installed at the end of the piston rod provides protection. This structure allows for significant support pressure within the bottom cylinder cavity when the sealing bladder is in its inflated, sealing state. Furthermore, when the fracturing body in the target fracturing area breaks and generates a shock wave, the baffle provides effective buffering protection. When the shock wave acts on the baffle, the piston's retraction compresses the gas or liquid within the bottom cylinder cavity. This compressed gas or liquid simultaneously acts on the sealing bladder and positioning mechanism, thus achieving a dual effect of enhanced sealing and positioning during the shock wave's action. Simultaneously, this compression process effectively absorbs the impact force, preventing it from directly impacting the sealing or positioning mechanism, thus providing effective protection and extending their service life.In addition, an annular limiting plate is fixedly installed on the outside of the bottom cylinder, and the two ends of the spring fitted on the outside of the bottom cylinder abut against the annular limiting plate and the baffle respectively. In this way, the spring can act on the baffle through its elastic force. Thus, when the baffle is subjected to impact force, the elastic force can absorb the impact force through elastic deformation. Furthermore, the spring can work in conjunction with the gas or liquid in the inner cavity of the bottom cylinder to absorb the impact force synchronously, significantly improving the buffering effect. This not only effectively protects the sealing and positioning unit but also effectively ensures the sealing and positioning effect, helping to ensure the cracking effect in the target area. In addition, this cooperative structure allows the piston rod and baffle to be pushed back to the set extension range by the elastic restoring force of the spring after the shock wave disappears. This is beneficial for better coping with intermittent shock wave conditions and thus can achieve good protective buffering function under complex impact conditions. By setting a buffer protection unit in front of the sealing and positioning mechanisms, the impact force generated during the cracking process can be effectively absorbed, thereby preventing the impact force from directly acting on the positioning and sealing mechanisms. This helps to ensure the positioning and sealing effects, thus ensuring the cracking effect in the cracking section, improving construction efficiency, and reducing construction costs. A fracturing tube is synchronously inserted into the sealing bladder, and the upper end of the inner connecting pipe of the telescopic injection tube is connected to the lower end of the fracturing tube. Simultaneously, the external injection pipe and the inner connecting pipe are slidably fitted together. This allows the telescopic injection pipe to extend and retract synchronously during the expansion and contraction of the damping support, avoiding motion interference between the two. The lower end of the external injection pipe is inserted into the mounting hole on the baffle, facilitating the supply of high-pressure water delivered through the fracturing tube to the target fracturing section outside the baffle via the telescopic injection pipe, thus achieving a stable and reliable high-pressure water delivery process. This invention can effectively absorb the impact force generated during fracturing, effectively ensure the sealing effect of the sealing bladder on the borehole, and effectively improve the positioning effect of the positioning mechanism within the borehole, achieving multiple improvements in sealing, positioning, and protective buffering effects.

[0007] The device has a reasonable structure and combines sealing, positioning and protective buffering functions. During the static fracturing process, it can simultaneously achieve reliable sealing of the borehole, reliable positioning within the hole and effective buffering of shock waves, which can significantly improve the fracturing effect and construction efficiency. At the same time, the device can be reused multiple times, which significantly reduces the fracturing construction cost.

[0008] Furthermore, to achieve efficient and reliable positioning within the borehole, the positioning mechanism includes a flat cylindrical body and radial positioners. The flat cylindrical body is coaxially connected to the outer side of the lower part of the plugging tube through a central mounting hole, and multiple mounting channels are evenly distributed circumferentially on its body. Multiple radial positioners are distributed one-to-one with the multiple mounting channels. Each radial positioner includes a radial cylinder, an anchoring pin, and a tension spring. The radial cylinder is radially fixedly inserted into the positioning channel, with an end plate encapsulated at its inner end, and a connecting hole at the center of the end plate. The anchoring pin is slidably inserted into the radial cylinder, and a piston head that slides and seals with the radial cylinder is fixedly connected to its inner end, with a pointed outer end. The tension spring is located in the radial cylinder, with its two ends connected to the end plate and the piston head, respectively. Connecting the flat cylindrical body to the lower part of the plugging tube ensures effective communication between the plugging tube and the flat cylindrical body, allowing high-pressure gas or high-pressure liquid in the plugging tube to directly enter the inner cavity of the flat cylindrical body. Multiple radial positioners are installed in the circumferential mounting channels of the flat cylinder, facilitating multi-directional positioning and ensuring effective positioning. A connecting hole is provided on the end plate at the inner end of the radial cylinder, and a tension spring is connected between the piston head and the end plate. This allows gas or liquid to be introduced into the radial cylinder through the connecting hole during the entry of high-pressure gas or liquid into the flat cylinder, pushing the piston head to extend the anchor pin radially for positioning. Simultaneously, when the gas or liquid pressure decreases or disappears, the tension spring causes the anchor pin to retract, facilitating timely release of the positioning state and allowing the device to be smoothly withdrawn from the borehole for recycling and reuse.

[0009] Furthermore, to ensure the sealing effect on the borehole, two sealing and positioning units are used, connected in a cascade manner. The lower end of the pressure plug tube in the upper sealing and positioning unit is fixedly connected to the upper end of the pressure plug tube in the lower sealing and positioning unit, and the lower end of the fracturing tube in the upper sealing and positioning unit is connected to the upper end of the fracturing tube in the lower sealing and positioning unit. Because the inner wall of underground boreholes is prone to unevenness and fracture development due to geological conditions, a single sealing capsule, after expansion, cannot completely conform to the borehole wall. Therefore, multiple sealing capsules can be used simultaneously to seal the borehole, improving the sealing performance. Simultaneously, multiple positioning mechanisms can improve the positioning effect within the borehole. Even if one sealing capsule ruptures or leaks, the other sealing capsules can still ensure the sealing effect, improving the reliability and stability of the sealing. Furthermore, even if one positioning mechanism fails, the remaining positioning mechanisms can still be used to ensure the positioning effect. This solves the problems of high-pressure medium leakage and failure to ensure sealing effect caused by traditional single sealing capsule structure, and positioning failure caused by single positioning mechanism. In addition, this cascaded structure can be quickly combined and replaced through standardized design, and can be flexibly adjusted according to actual engineering needs.

[0010] Furthermore, to facilitate flexible control of the filling process, a pressure-injecting mechanism is also included. This mechanism comprises a valve and a pressure-injecting pipeline. The outlet end of the valve is fixedly connected to the upper end of the pressure-sealing pipe in the upper sealing and positioning unit. The outlet end of the pressure-injecting pipeline is connected to the inlet end of the valve. Thus, a water pump or air pump can be connected to the pressure-injecting pipeline to introduce high-pressure gas or high-pressure liquid. Simultaneously, the filling process of gas or liquid can be controlled by opening and closing the valve.

[0011] Furthermore, to facilitate rapid assembly and disassembly, the upper inner side of the plugging tube is provided with an internally threaded connecting section A, and the lower outer side is provided with an externally threaded connecting section A. The upper inner side of the bottom cylinder is provided with an internally threaded connecting section B. The externally threaded connecting section A at the lower end of the plugging tube is inserted into the internally threaded connecting section B at the upper end of the bottom cylinder through threaded engagement. When two adjacent plugging tubes are connected, the externally threaded connecting section A at the lower end of the upper plugging tube is inserted into the internally threaded connecting section A at the upper end of the lower plugging tube through threaded engagement. In this way, when multiple plugging and positioning units are set up simultaneously, the threaded engagement enables rapid assembly and disassembly of the plugging and positioning units, improving assembly flexibility. At the same time, the setting of multiple plugging and positioning units can effectively ensure the plugging and positioning effects.

[0012] As a preferred embodiment, the inner connecting tube is fixedly connected to the bottom cylinder via a connecting arm.

[0013] Furthermore, to facilitate quick connection and disconnection, quick connectors are provided at both the upper and lower ends of the fracturing tube.

[0014] Furthermore, to ensure the service life of the occlusion capsule, the occlusion capsule is made of nano-modified rubber material, which is made by adding 5% to 10% nano-silica and 2% to 5% nano-carbon fiber by mass fraction to natural rubber for composite modification.

[0015] Furthermore, to ensure the hardness of the anchoring pin, the anchoring pin is integrally formed from gradient cemented carbide material. Its pointed structure is made of WC-Co cemented carbide, and the part outside the pointed structure is made of 40CrNiMoA alloy. The WC-Co cemented carbide and the 40CrNiMoA alloy are metallurgically bonded by hot pressing sintering. The Co mass fraction in the WC-Co cemented carbide layer is 12% to 15%.

[0016] Furthermore, to prevent the baffle from getting stuck in the hole and to facilitate its easy removal from the borehole during the recovery process, the baffle has a frustum-shaped cross-section, with the outer diameter of the lower end being smaller than that of the upper end. Attached Figure Description

[0017] Figure 1This is a three-dimensional structural diagram of the present invention; Figure 2 This is a schematic diagram of the analytical structure of the present invention; Figure 3 This is a cross-sectional view of the blocking and positioning unit in this invention; Figure 4 This is a cross-sectional view of the positioning mechanism in this invention; Figure 5 This is a three-dimensional structural diagram of the buffer protection unit in this invention; Figure 6 This is a cross-sectional view of the buffer protection unit in this invention.

[0018] In the diagram: 1. Pressure plugging tube; 2. Sealing bladder; 3. Rupture tube; 4. Quick connector one; 5. Liquid outlet; 6. Pressure inlet mechanism; 7. Flat cylinder; 8. Radial cylinder; 9. Anchor pin; 10. End plate; 11. Tension spring; 12. Bottom cylinder; 13. Piston; 14. Piston rod; 15. Baffle; 16. Spring; 17. External injection pipe; 18. Internal connecting pipe; 19. Annular limiting plate; 20. Sealing and positioning unit; 21. Buffer protection unit; 22. Sealing mechanism; 23. Positioning mechanism; 24. Connecting arm; 25. Piston head; 26. Damping support body; 27. Telescopic injection pipe; 28. Valve; 29. ​​Pressure inlet pipeline; 30. Internal threaded connection section A; 31. External threaded connection section A; 32. Internal threaded connection section B; 33. Quick connector two. Detailed Implementation

[0019] The invention will now be further described with reference to the accompanying drawings.

[0020] like Figures 1 to 6 As shown, the present invention provides a nano-expansion fracturing capsule device for underground engineering, including a sealing and positioning unit 20 and a buffer protection unit 21; The sealing and positioning unit 20 includes a sealing mechanism 22 and a positioning mechanism 23. The sealing mechanism 22 includes a sealing bladder 2, a pressure plugging tube 1, and a fracturing tube 3. The pressure plugging tube 1 is inserted into the sealing bladder 2 in the height direction. Preferably, the pressure plugging tube 1 is located at the axis of the sealing bladder 2, and the connection between the pressure plugging tube 1 and the sealing bladder 2 is fixed and sealed. The pressure plugging tube 1 has multiple liquid outlet holes 5 in the inner cavity of the sealing bladder 2. The fracturing tube 3 is spaced apart from the pressure plugging tube 1 and is inserted into the sealing bladder 2 in the height direction. Preferably, the connection between the fracturing tube 3 and the sealing bladder 2 is fixed and sealed. The positioning mechanism 23 is located below the sealing bladder 2 and is fixedly connected to the outer side of the lower part of the pressure plugging tube 1. The positioning mechanism 23 operates synchronously with the sealing bladder 2. When the sealing bladder 2 expands, the positioning mechanism 23 extends radially and is radially positioned by pressing against the rock wall. When the sealing bladder 2 retracts, the positioning mechanism 23 retracts radially. The buffer protection unit 21 is located below the sealing and positioning unit 20, and includes a damping support 26 and a telescopic injection tube 27. The damping support 26 includes a bottom cylinder 12, a piston 13, a piston rod 14, a baffle 15, an annular limiting plate 19, and a spring 16. The upper end of the bottom cylinder 12 is fixedly connected to the lower end of the plugging tube 1, and a guide ring is fixedly connected to the inner side of its lower end. The piston 13 is slidably and sealingly assembled in the inner cavity of the bottom cylinder 12. The piston rod 14 is slidably assembled inside the guide ring, and its upper end is fixedly connected to the central area of ​​the piston 13. The size of the baffle 15 is adapted to the size of the borehole, preferably slightly smaller than the borehole diameter. The baffle 15 is fixedly connected to the lower end of the piston rod 14. To improve the versatility of the baffle 15, it is preferably a circular plate. The annular limiting plate 19 is fixedly fitted on the outside of the bottom cylinder 12. The spring 16 is sleeved on the outside of the bottom cylinder 12, and its upper and lower ends abut against the annular limiting plate 19 and the baffle 15, respectively. The telescopic injection tube 27 includes an inner connecting tube 18 and an outer injection tube 17. The inner connecting tube 18 is fixedly supported on one side of the bottom cylinder 12, and its upper end is connected to the lower end of the fracturing tube 3. The outer injection tube 17 is axially slidably fitted on the outside of the inner connecting tube 18, and its lower end is fixedly inserted into the mounting hole on the baffle 15.

[0021] To achieve efficient and reliable positioning within the borehole, the positioning mechanism 23 includes a flat cylindrical body 7 and radial positioners. The flat cylindrical body 7 is coaxially connected to the outer side of the lower part of the plugging pipe 1 through a central mounting through-hole, and multiple mounting channels are evenly distributed circumferentially on its body. Multiple radial positioners are distributed one-to-one with multiple mounting channels. Each radial positioner includes a radial cylinder 8, an anchoring pin 9, and a tension spring 11. The radial cylinder 8 is radially fixedly inserted into the positioning channel, and its inner end is encapsulated with an end plate 10, with a connecting hole at the center of the end plate 10. In this design, the radial cylinder 8 and the flat cylinder 7 are connected by a sealed connection to ensure that gas or liquid does not leak from the connection. The anchoring pin 9 is slidably inserted into the radial cylinder 8, and its inner end is fixedly connected to a piston head 25 that slides and seals with the radial cylinder 8. Its outer end has a pointed structure, and to effectively reduce the embedding resistance, the angle of the pointed structure is preferably 30° to 45°, thus ensuring effective anchoring even under low hydraulic / pneumatic pressure. The tension spring 11 is disposed in the radial cylinder 8, and its two ends are respectively connected to the end plate 10 and the piston head 25. Connecting the flat cylinder in series with the lower part of the pressure plug tube ensures effective communication between the pressure plug tube and the flat cylinder, allowing high-pressure gas or high-pressure liquid in the pressure plug tube to directly enter the inner cavity of the flat cylinder. Installing multiple radial positioners in multiple installation channels in the circumferential direction of the flat cylinder facilitates positioning in multiple directions in the circumferential direction, which helps to ensure the positioning effect. A connecting hole is provided on the end plate at the inner end of the radial cylinder. At the same time, a tension spring is connected between the piston head and the end plate. In this way, when the flat cylinder is filled with high-pressure gas or high-pressure liquid, the gas or liquid can be introduced into the radial cylinder through the connecting hole to push the piston head and drive the anchor pin to extend radially for radial positioning. At the same time, when the gas or liquid pressure decreases or disappears, the tension spring can cause the anchor pin to retract, so as to release the positioning state in time. This facilitates the smooth withdrawal of the device from the borehole, achieving the purpose of recycling and reuse.

[0022] To ensure effective sealing of the borehole, two sealing and positioning units 20 are used, connected in a cascade manner. The lower end of the pressure plug 1 in the upper sealing and positioning unit 20 is fixedly connected to the upper end of the pressure plug 1 in the lower sealing and positioning unit 20, and the lower end of the fracturing tube 3 in the upper sealing and positioning unit 20 is connected to the upper end of the fracturing tube 3 in the lower sealing and positioning unit 20. Because the inner wall of underground boreholes is prone to unevenness and fracture development due to geological conditions, a single sealing capsule, after expansion, cannot completely conform to the borehole wall. Therefore, multiple sealing capsules can be used simultaneously to seal the borehole, improving sealing performance. Simultaneously, multiple positioning mechanisms can improve the positioning effect within the borehole. Even if one sealing capsule ruptures or leaks, the other sealing capsules can still ensure the sealing effect, improving the reliability and stability of the sealing. Furthermore, even if one positioning mechanism fails, the remaining positioning mechanisms can still be used to ensure the positioning effect. This solves the problems of high-pressure medium leakage and failure to ensure sealing effect caused by traditional single sealing capsule structure, and positioning failure caused by single positioning mechanism. In addition, this cascaded structure can be quickly combined and replaced through standardized design, and can be flexibly adjusted according to actual engineering needs.

[0023] As a preferred option, the number of sealing and positioning units 20 can also be greater than two. The specific number of sealing and positioning units 20 can be flexibly determined according to the specific fracturing conditions.

[0024] To facilitate flexible control of the filling process, a pressure-injecting mechanism 6 is also included. The pressure-injecting mechanism 6 comprises a valve 28 and a pressure-injecting pipeline 29. The outlet end of the valve 28 is fixedly connected to the upper end of the pressure-blocking pipe 1 in the upper sealing and positioning unit 20. The outlet end of the pressure-injecting pipeline 29 is connected to the inlet end of the valve 28. Thus, a water pump or air pump can be connected to the pressure-injecting pipeline to introduce high-pressure gas or high-pressure liquid. Simultaneously, the filling process of gas or liquid can be controlled by opening and closing the valve.

[0025] To facilitate rapid assembly and disassembly, the upper inner side of the plugging tube 1 is provided with an internally threaded connecting section A30, and the lower outer side is provided with an externally threaded connecting section A31. The upper inner side of the bottom cylinder 12 is provided with an internally threaded connecting section B32. The externally threaded connecting section A31 at the lower end of the plugging tube 1 is threadedly inserted into the internally threaded connecting section B32 at the upper end of the bottom cylinder 12. When two adjacent plugging tubes 1 are connected, the externally threaded connecting section A31 at the lower end of the upper plugging tube 1 is threadedly inserted into the internally threaded connecting section A30 at the upper end of the lower plugging tube 1. This not only facilitates the rapid assembly and disassembly process between two adjacent plugging tubes 1, but also facilitates the rapid assembly and disassembly between the plugging tube 1 and the bottom cylinder 12. In this way, when multiple plugging and positioning units are set up simultaneously, the threaded connection enables the rapid assembly and disassembly of the plugging and positioning units, improving the flexibility of assembly. At the same time, the setting of multiple plugging and positioning units can effectively ensure the sealing and positioning effects.

[0026] As a preferred embodiment, the inner connecting tube 18 is fixedly connected to the bottom cylinder 12 via the connecting arm 24.

[0027] To facilitate quick connection and disconnection, quick-connect couplings 4 are connected to both the upper and lower ends of the fracturing tube 3. This allows for connection between the two fracturing tubes 3 via quick-connect couplings 4. High-pressure fittings, such as high-pressure hoses, can also be used to connect the two fracturing tubes 3. Alternatively, quick-connect coupling 33 is connected to the upper end of the inner connecting tube 18, allowing for quick connection between the fracturing tube 3 and the inner connecting tube 18 using high-pressure fittings. Both quick-connect couplings 4 and 33 are existing technologies, such as common pipeline quick-connect couplings.

[0028] To ensure the service life of the sealing bladder, the sealing bladder 2 is made of nano-modified rubber material. This nano-modified rubber material is made by adding 5%–10% nano-silica and 2%–5% nano-carbon fiber by mass to natural rubber for composite modification. The addition of nano-carbon fiber creates a three-dimensional network reinforcement structure, significantly improving the fatigue resistance and dynamic mechanical properties of the sealing bladder, making it less prone to permanent deformation during repeated pressurization-depressurization cycles. The surface-modified nanoparticles have a higher interfacial bonding strength with the rubber matrix, synergistically improving the material's chemical corrosion resistance and protecting it from the erosion of the bladder by acidic water and slag leachate commonly encountered in underground engineering. Simultaneously, this composite modified material maintains good elasticity while ensuring high strength, allowing the sealing bladder to tightly conform to the borehole walls of different diameters after pressurization, significantly improving sealing performance and effectively preventing high-pressure media leakage.

[0029] To ensure the hardness of the anchor pin, the anchor pin 9 is integrally formed from a gradient cemented carbide material. Its pointed portion is made of WC-Co cemented carbide, while the portion outside the pointed portion is made of 40CrNiMoA alloy. The WC-Co cemented carbide and 40CrNiMoA alloy are metallurgically bonded through hot-pressing sintering. The Co content in the WC-Co cemented carbide layer is 12%–15% by mass. Using high-cobalt-content WC-Co cemented carbide for the pointed portion of the anchor pin 9 fully utilizes the advantages of the cemented carbide's ultra-high hardness and wear resistance. When extended radially under pressure, it can easily embed into the rock mass inside the borehole, forming a reliable anchor point and preventing displacement of the device under fracturing impact. Using 40CrNiMoA alloy for the portion outside the pointed portion allows the main support to possess both high strength and excellent toughness, which helps buffer the impact load during fracturing and prevents the anchor pin from breaking due to excessive rigidity. Metallurgical bonding achieved through hot pressing and sintering can eliminate interface defects between the two layers of materials, ensuring that the head and tail form an integral load-bearing structure, preventing delamination and detachment during repeated expansion and contraction, thus ensuring anchoring reliability and extending its service life, and meeting the long-term use requirements under complex geological conditions in underground engineering.

[0030] To ensure effective positioning while minimizing structural complexity and manufacturing costs, the radial positioner is configured as four units.

[0031] To prevent the baffle from getting stuck in the hole and to facilitate its easy removal from the borehole during the recovery process, the baffle 15 has a frustum-shaped cross section, with the outer diameter of the lower end being smaller than that of the upper end.

[0032] Working principle: After drilling, a fracturing capsule (made of glass or plastic and containing chemical powder or liquid for fracturing) is first placed in the section to be fracturing. Then, the underground engineering nano-expansion fracturing capsule device is pushed to the set depth inside the borehole, and the baffle 15 is stopped at the outside of the fracturing section. A water pump or air pump is connected to the inlet end of the pressure inlet pipe 29, and the valve 28 is opened. High-pressure liquid or high-pressure air is simultaneously injected into the damping support 26, the positioning mechanism 23 and the sealing capsule 2 through the pressure plugging pipe 1. After the high-pressure liquid or high-pressure air enters the bottom cylinder 12, it pushes the piston 13, which drives the piston rod 14 and the baffle 15 to extend towards the bottom of the hole until the maximum extension is reached. After high-pressure liquid or high-pressure air enters the flat cylinder 7 through the liquid permeation hole on the plugging pipe 1, it enters the radial cylinder 8 through the connecting hole on the end plate 10, thereby pushing the piston head 25 to drive the anchor pin 9 to extend radially until it reaches its maximum extension state. During this process, the pointed structure at the outer end of the anchor pin 9 will penetrate into the rock mass, achieving reliable positioning of the capsule device in the hole. After high-pressure liquid or high-pressure air enters the inner cavity of the sealing bladder 2 through the liquid outlet hole 5 on the plugging pipe 1, it will cause the sealing bladder 2 to fully expand until it reaches the predetermined pressure state, at which point the valve 28 is closed to stop. At this time, the sealing bladder 2 is fully expanded and completely seals the hole.

[0033] High-pressure water is injected through the fracturing tube 3 and delivered to the target fracturing section outside the baffle 15 through the telescopic injection tube 27. The high-pressure water acts on the fracturing capsule, which ruptures under the action of the high-pressure water. The chemical powder or liquid inside comes into full contact with the high-pressure water and reacts, generating a large amount of water-insoluble gas in the target fracturing section in a short time, forming a high-pressure environment. Under the pressure of continuous expansion, the rock fractures, achieving static fracturing of the rock mass. Simultaneously, the shock wave generated during the fracturing process acts synchronously on the baffle 15. The pressure of the gas or liquid inside the bottom cylinder 12, combined with the spring 16, provides damping support to counteract the shock wave. As the shock wave pushes the baffle 15 back, it simultaneously compresses the gas or liquid inside the bottom cylinder 12, increasing the gas or liquid pressure in the positioning mechanism 23 and the sealing bladder 2, achieving multiple effects of simultaneously increasing sealing, positioning, and protective buffering. After completing the static fracturing operation, the valve 28 is opened, and the pressure is released through the pressure plug 1, allowing the sealing bladder 2 to naturally retract under the elastic recovery action. The elastic tension of the tension spring 11 causes the anchor pin 9 to detach from the rock mass and retract into the radial cylinder 8. The underground engineering nano-expansion fracturing device is then removed, completing the recovery operation.

[0034] In this invention, a pressure plugging tube is installed throughout the occlusion bladder, and multiple liquid outlet holes are provided on the tube. This facilitates the injection of high-pressure gas or high-pressure liquid into the occlusion bladder via the pressure plugging tube, enabling control of its expansion or contraction. Furthermore, when the positioning mechanism requires pneumatic or hydraulic actuation, the pressure plugging tube provides the necessary pneumatic or hydraulic power, facilitating synchronized drive control between the positioning mechanism and the occlusion bladder. Additionally, when the lower end of the pressure plugging tube connects to the bottom cylinder of the damping support, it also allows for the synchronous supply of high-pressure gas or high-pressure liquid to the damping support, enabling pneumatic or hydraulic actuation of the damping support to reach its maximum extension. A positioning mechanism is installed below the plugging bladder, and its operation is synchronized with that of the plugging bladder. This allows for reliable positioning within the borehole while the plugging bladder seals the borehole, preventing slippage of the plugging material. Especially during fracturing operations, the positioning mechanism effectively counteracts the impact force, ensuring reliable, targeted plugging and guaranteeing the fracturing effect. Furthermore, this synchronized mechanism allows the positioning mechanism to retract synchronously with the retraction of the plugging bladder, facilitating overall recovery and reuse. In the damping support, a piston is slidably sealed in the bottom cylinder, and the bottom cylinder is connected to the plugging pipe. Thus, when the plugging bladder expands, high-pressure gas or high-pressure liquid will enter the bottom cylinder simultaneously and drive the piston to extend the piston rod outward until the maximum stroke is reached. This will drive the baffle installed at the end of the piston rod to extend towards the bottom of the hole. The guide ring at the lower end of the bottom cylinder not only guides the piston rod during its movement but also limits the piston's stroke. The baffle fixedly installed at the end of the piston rod provides protection. This structure allows for significant support pressure within the bottom cylinder cavity when the sealing bladder is in its inflated, sealing state. Furthermore, when the fracturing body in the target fracturing area breaks and generates a shock wave, the baffle provides effective buffering protection. When the shock wave acts on the baffle, the piston's retraction compresses the gas or liquid within the bottom cylinder cavity. This compressed gas or liquid simultaneously acts on the sealing bladder and positioning mechanism, thus achieving a dual effect of enhanced sealing and positioning during the shock wave's action. Simultaneously, this compression process effectively absorbs the impact force, preventing it from directly impacting the sealing or positioning mechanism, thus providing effective protection and extending their service life.In addition, an annular limiting plate is fixedly installed on the outside of the bottom cylinder, and the two ends of the spring fitted on the outside of the bottom cylinder abut against the annular limiting plate and the baffle respectively. In this way, the spring can act on the baffle through its elastic force. Thus, when the baffle is subjected to impact force, the elastic force can absorb the impact force through elastic deformation. Furthermore, the spring can work in conjunction with the gas or liquid in the inner cavity of the bottom cylinder to absorb the impact force synchronously, significantly improving the buffering effect. This not only effectively protects the sealing and positioning unit but also effectively ensures the sealing and positioning effect, helping to ensure the cracking effect in the target area. In addition, this cooperative structure allows the piston rod and baffle to be pushed back to the set extension range by the elastic restoring force of the spring after the shock wave disappears. This is beneficial for better coping with intermittent shock wave conditions and thus can achieve good protective buffering function under complex impact conditions. By setting a buffer protection unit in front of the sealing and positioning mechanisms, the impact force generated during the cracking process can be effectively absorbed, thereby preventing the impact force from directly acting on the positioning and sealing mechanisms. This helps to ensure the positioning and sealing effects, thus ensuring the cracking effect in the cracking section, improving construction efficiency, and reducing construction costs. A fracturing tube is synchronously inserted into the sealing bladder, and the upper end of the inner connecting pipe of the telescopic injection tube is connected to the lower end of the fracturing tube. Simultaneously, the external injection pipe and the inner connecting pipe are slidably fitted together. This allows the telescopic injection pipe to extend and retract synchronously during the expansion and contraction of the damping support, avoiding motion interference between the two. The lower end of the external injection pipe is inserted into the mounting hole on the baffle, facilitating the supply of high-pressure water delivered through the fracturing tube to the target fracturing section outside the baffle via the telescopic injection pipe, thus achieving a stable and reliable high-pressure water delivery process. This invention can effectively absorb the impact force generated during fracturing, effectively ensure the sealing effect of the sealing bladder on the borehole, and effectively improve the positioning effect of the positioning mechanism within the borehole, achieving multiple improvements in sealing, positioning, and protective buffering effects.

[0035] The device has a reasonable structure and combines sealing, positioning and protective buffering functions. During the static fracturing process, it can simultaneously achieve reliable sealing of the borehole, reliable positioning within the hole and effective buffering of shock waves, which can significantly improve the fracturing effect and construction efficiency. At the same time, the device can be reused multiple times, which significantly reduces the fracturing construction cost.

Claims

1. A nano-expansion-induced fracturing capsule device for underground engineering, comprising a sealing and positioning unit (20), characterized in that, It also includes a buffer protection unit (21); The sealing and positioning unit (20) includes a sealing mechanism (22) and a positioning mechanism (23); the sealing mechanism (22) includes a sealing bladder (2), a pressure plug (1) and a fracturing tube (3); the pressure plug (1) is inserted into the sealing bladder (2) in the height direction, and the pressure plug (1) has multiple liquid outlet holes (5) in the part of the sealing bladder (2) cavity; the fracturing tube (3) is distributed at intervals with the pressure plug (1) and is inserted into the sealing bladder (2) in the height direction; the positioning mechanism (23) is located below the sealing bladder (2) and is fixedly connected to the outer side of the lower part of the pressure plug (1). The positioning mechanism (23) moves synchronously with the sealing bladder (2). When the sealing bladder (2) expands, it extends radially synchronously and is radially positioned by pressing against the rock wall. When the sealing bladder (2) retracts, it retracts radially synchronously. The buffer protection unit (21) includes a damping support (26) and a telescopic injection tube (27); the damping support (26) includes a bottom cylinder (12), a piston (13), a piston rod (14), a baffle (15), an annular limiting plate (19), and a spring (16); the upper end of the bottom cylinder (12) is fixedly connected to the lower end of the pressure plug tube (1), and a guide ring is fixedly connected to the inner side of its lower end; the piston (13) is slidably and sealingly assembled in the inner cavity of the bottom cylinder (12); the piston rod (14) is slidably assembled inside the guide ring, and its upper end is fixedly connected to the piston (13); the size of the baffle (15) is adapted to the size of the borehole. The ring limiting plate (19) is fixedly fitted on the outside of the bottom cylinder (12); the spring (16) is fitted on the outside of the bottom cylinder (12), and its upper and lower ends abut against the ring limiting plate (19) and the baffle (15) respectively; the telescopic injection tube (27) includes an inner connecting tube (18) and an outer injection tube (17); the inner connecting tube (18) is fixedly supported on one side of the bottom cylinder (12), and its upper end is connected to the lower end of the fracturing tube (3); the outer injection tube (17) is axially slidably fitted on the outside of the inner connecting tube (18), and its lower end is fixedly inserted into the mounting hole on the baffle (15).

2. The nano-expansion-induced fracture capsule device for underground engineering according to claim 1, characterized in that, The positioning mechanism (23) includes a flat cylinder (7) and a radial positioner; the flat cylinder (7) is coaxially connected to the outer side of the lower part of the pressure plug tube (1) through the central mounting through hole, and multiple mounting channels are evenly opened around its cylinder body; multiple radial positioners are distributed one-to-one with multiple mounting channels; the radial positioner includes a radial cylinder (8), an anchor pin (9) and a tension spring (11); the radial cylinder (8) is radially fixedly inserted into the positioning channel, and its inner end is encapsulated with an end plate (10), and the center of the end plate (10) is provided with a connecting hole; the anchor pin (9) is slidably inserted into the radial cylinder (8), and its inner end is fixedly connected to a piston head (25) that slides and seals with the radial cylinder (8), and its outer end is a pointed structure; the tension spring (11) is set in the radial cylinder (8), and its two ends are respectively connected to the end plate (10) and the piston head (25).

3. The underground engineering nano-expansion-induced fracture capsule device according to claim 1, characterized in that, The number of the sealing and positioning units (20) is two. The two sealing and positioning units (20) are connected in a cascade manner. The lower end of the pressure plug (1) in the upper sealing and positioning unit (20) is fixedly connected to the upper end of the pressure plug (1) in the lower sealing and positioning unit (20). The lower end of the rupture tube (3) in the upper sealing and positioning unit (20) is connected to the upper end of the rupture tube (3) in the lower sealing and positioning unit (20).

4. The underground engineering nano-expansion-induced fracture capsule device according to claim 1, characterized in that, It also includes a pressure inlet mechanism (6), which includes a valve (28) and a pressure inlet pipeline (29); the outlet end of the valve (28) is fixedly connected to the upper end of the pressure plug pipe (1) in the upper sealing and positioning unit (20); the outlet end of the pressure inlet pipeline (29) is connected to the inlet end of the valve (28).

5. The underground engineering nano-expansion fracturing capsule device according to claim 1, characterized in that, The upper inner side of the pressure plug (1) is provided with an internal threaded connection section A (30), and the lower outer side is provided with an external threaded connection section A (31). The upper inner side of the bottom cylinder (12) is provided with an internal threaded connection section B (32). The external threaded connection section A (31) at the lower end of the pressure plug (1) is inserted into the internal threaded connection section B (32) at the upper end of the bottom cylinder (12) through threaded engagement. When two adjacent pressure plugs (1) are connected, the external threaded connection section A (31) at the lower end of the upper pressure plug (1) is inserted into the internal threaded connection section A (30) at the upper end of the lower pressure plug (1) through threaded engagement.

6. The underground engineering nano-expansion fracturing capsule device according to claim 1, characterized in that, The inner connecting pipe (18) is fixedly connected to the bottom cylinder (12) via the connecting arm (24).

7. The underground engineering nano-expansion fracturing capsule device according to claim 1, characterized in that, The upper and lower ends of the rupture tube (3) are both connected to quick connectors (4).

8. The underground engineering nano-expansion fracturing capsule device according to claim 1, characterized in that, The occlusion capsule (2) is made of nano-modified rubber material, which is made by adding 5% to 10% nano-silica and 2% to 5% nano-carbon fiber by mass fraction to natural rubber for composite modification.

9. The underground engineering nano-expansion fracturing capsule device according to claim 2, characterized in that, The anchoring pin (9) is integrally formed from gradient hard alloy material. Its pointed structure is made of WC-Co hard alloy, and the part outside the pointed structure is made of 40CrNiMoA alloy. The WC-Co hard alloy and the 40CrNiMoA alloy are metallurgically bonded by hot pressing sintering. The Co mass fraction in the WC-Co hard alloy layer is 12% to 15%.

10. The underground engineering nano-expansion fracturing capsule device according to claim 1, characterized in that, The cross-section of the baffle (15) is frustum-shaped, and the outer diameter of the lower end is smaller than that of the upper end.

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