A Leakage Monitoring Lead, Mitigation Structure and Preparation Method for a High-Pressure Hydrogen Storage Chamber

Abstract

The present invention belongs to the technical field of underground gas storage, and particularly relates to a leakage monitoring lead wire, a mitigation structure and a preparation method for a high-pressure hydrogen storage chamber. The leakage monitoring lead wire and mitigation structure for the high-pressure hydrogen storage chamber disclosed by the present invention can capture temperature anomalies and accurately locate the positions of steel lining cracks through a distributed optical fiber temperature measurement system, facilitating timely repair; the sealing connector ensures that there is no hydrogen leakage at the optical fiber lead wire in the chamber, realizing leakage monitoring while ensuring the sealing performance; the surrounding rock is restricted from damage and cracking and the leakage channels are reduced through prestressed anchor rods, anchor cables and the internal prestressed lining thereof; the prestressed lining stress layer is arranged on the inner side of the surrounding rock, and a hydrogen storage material capable of adsorbing hydrogen is uniformly added during the injection molding process. The bentonite slip anti-seepage layer is arranged between the stress layer and the steel lining. The prestressed lining and the slip layer restrict the damage and cracking of the lining and reduce the leakage channels; the hydrogen storage and adsorption material and the bentonite slip layer in the lining can form multiple barriers for mitigating gas leakage.

Description

Technical Field

[0001] The present invention belongs to the technical field of underground gas storage, and in particular relates to a leakage monitoring lead and a mitigation structure for a high-pressure hydrogen storage chamber, and a preparation method thereof. Background Art

[0002] High-pressure gas storage chambers are used to store high-pressure gases such as natural gas and hydrogen. Leakage may cause serious safety accidents such as fire and explosion. Real-time monitoring of leakage is crucial, but the indoor and outdoor environment of the chamber is complex. Traditional monitoring methods such as infrared thermal imaging and gas sensors have limitations such as limited coverage, slow response time, and high maintenance costs. Distributed fiber optic temperature measurement technology uses optical fiber as a transmission medium, which not only solves the above limitations, but also has the advantages of real-time monitoring of small temperature changes and no electromagnetic interference. In addition, to alleviate the problem of hydrogen leakage, a composite structure can be used to limit the degree of damage and cracking of the chamber, and a variety of hydrogen storage materials are used in high-pressure gas storage chambers. Hydrogen is efficiently adsorbed through physical and chemical adsorption, which can effectively reduce the spread of leakage and potential hazards.

[0003] During the operation monitoring of the gas storage chamber, the lead wire is the key link between the chamber sensor element and the external data acquisition equipment. The risk of gas leakage along the opening of the hole in the chamber is inevitable. The sealing performance of the chamber is directly related to the safety and operation efficiency of the gas storage chamber. However, the technical challenges faced by the lead wire sealing are quite severe, mainly including the complex and changeable geological environment, extreme working conditions of high pressure and high temperature, and harsh underground construction conditions. These factors may not only lead to the aging and failure of the sealing material, but also put forward extremely high requirements on the durability and performance of the sealing material, and also significantly increase the difficulty of construction.

[0004] Therefore, the sealing problem of the lead-out wire of the gas storage chamber is the key technical challenge to realize the leakage monitoring of the gas storage chamber. In addition, the structural crack limitation design and gas leakage mitigation design of the gas storage chamber are important measures to enhance the sealing performance of the gas storage chamber. Summary of the invention

[0005] In view of this, the first object of the present invention is to provide a high-pressure hydrogen storage chamber leakage monitoring lead and mitigation structure to address the problems existing in the prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A leakage monitoring lead and mitigation structure for a high-pressure hydrogen storage chamber includes, from outside to inside, surrounding rock, a stress-bearing layer, a sliding resistance layer, and a sealed steel lining, wherein:

[0008] Anchor rods and anchor cables are driven into the surrounding rock;

[0009] The stress-bearing layer is a prestressed concrete stress-bearing layer with a thickness of 600-900 mm;

[0010] The thickness of the sliding resistance and seepage prevention layer is 10 - 15 mm, which is composed of a middle filling layer and geotextiles on the inner and outer sides; among them, the outer geotextile is arranged on the inner side of the stress-bearing layer, and a drag reduction film is arranged between the outer geotextile and the filling layer; the inner geotextile is arranged on the outer side of the steel lining;

[0011] The thickness of the steel lining is 15 - 20 mm, which is connected to the external gas transmission pipe. An air vent valve is installed near the outer end of the gas transmission pipe, and the outermost end is sealed with a flange connector.

[0012] Furthermore, the anchor rods are prestressed anchor rods, and the anchor cables are prestressed anchor cables.

[0013] Furthermore, the leakage monitoring lead and mitigation structure of the high-pressure hydrogen storage chamber further includes: the distributed optical fiber temperature measurement system monitoring part is located inside the steel lining, the optical fiber demodulator is located outside the chamber, the optical fiber is arranged at the reserved groove on the inner wall of the steel lining and led out of the chamber through a sealing connector and connected to the optical fiber demodulator;

[0014] The hydrogen storage material is activated carbon, and it is evenly distributed in the stress-bearing layer and the filling layer.

[0015] It should be noted that in the present invention, a sliding resistance and seepage prevention layer is provided between the stress-bearing layer and the steel lining to adsorb trace hydrogen diffused out along the steel lining and inhibit shear failure of the stress-bearing layer; and a prestressed concrete stress-bearing layer added with activated carbon is adopted, which can not only provide prestress to resist the tensile stress transmitted by high-pressure hydrogen to the stress-bearing layer, but also further adsorb hydrogen after hydrogen breaks through the sliding resistance and seepage prevention layer and enters the stress-bearing layer, achieving dual protection of inhibiting crack formation to form a leakage path and adsorbing gas to slow down leakage; pre-grouting of the surrounding rock is carried out by drilling holes before the excavation of the surrounding rock, which greatly improves the strength of the surrounding rock.

[0016] In addition, once the steel lining itself or the steel lining weld cracks and leaks during the storage of high-pressure hydrogen in the hydrogen storage chamber, the distributed optical fiber temperature measurement system can promptly detect the temperature anomaly caused by this hydrogen leakage, quickly and accurately locate the position of the steel lining crack, and notify the maintenance personnel for rapid repair and maintenance to avoid disasters.

[0017] Moreover, considering that the lead of the sensor optical fiber must be realized through a hole, the sealing connector in the present invention can effectively seal the lead-out of the optical fiber, solve the problem of easy leakage of hydrogen from the lead-out hole of the lead wire, and provide an idea for the lead wire problem of the sealed gas storage chamber.

[0018] In some embodiments, the filling layer uses bentonite as the filling material, and the drag reduction film uses polytetrafluoroethylene film.

[0019] Further, the optical fiber is a single-mode temperature-sensing optical fiber, and the optical fiber is a single-mode temperature-sensing optical fiber. The fiber inlet / outlet part of the sealing connector and the reserved groove on the inner wall of the steel lining are sealed with a sealing material.

[0020] Furthermore, the sealing material includes one or a combination of polypropylene flexible material, bentonite, and epoxy resin.

[0021] Furthermore, the sealing connector includes a metal rod, and a hole for wrapping the optical fiber is arranged inside the metal rod; the head section of the hole is expanded in diameter, the middle section is serrated, a trapezoidal polypropylene flexible material is nested between the head section and the middle section, and a triangular polypropylene flexible material is arranged at the tail end.

[0022] Furthermore, after the optical fiber is arranged, the head and tail ends of the metal rod are covered with bentonite and polypropylene flexible material, and the remaining internal part is injected with epoxy resin.

[0023] It should be noted that at the head and tail ends of the optical fiber entering the metal rod, a layer of bentonite is first evenly covered. By injecting an appropriate amount of water into the bentonite, the bentonite quickly absorbs water and swells, forming a dense sealing layer, which further improves the densification effect of the sealing connector; injecting high-strength epoxy resin into the remaining space in the metal rod ensures the sealing performance of the connector; between the head section and the middle section of the metal rod, a trapezoidal polypropylene flexible material is nested, and a triangular polypropylene flexible material is also configured at the tail end, which can maintain the sealing performance of the contact surface between the concrete and the sealing connector under high-pressure environment. When the metal rod undergoes a small deformation under high pressure, the polypropylene flexible materials in the middle and at the tail end can be further compacted, thereby achieving a more excellent sealing effect. The above structure forms a multiple sealing barrier for the sealing connector.

[0024] In particular, the synergistic use of polypropylene flexible material and bentonite in the sealing connector can not only effectively seal the inlet and outlet of the lead wire to avoid hydrogen leakage, but also play a role in fixing and protecting the optical fiber. The epoxy resin can further seal, achieving a double-sealing effect. Therefore, any technical solution that adopts this sealing structure without creative work falls within the protection scope of the present invention.

[0025] Furthermore, metal rings are configured at the head and tail ends of the optical fiber for dense fixation. A fixing piece is welded to the part of the metal rod protruding from the plug, and is fixed to the plug through an expansion screw.

[0026] Thus, the optical fiber of the present invention is tightly connected to the optical fiber demodulator outside the chamber through a carefully designed sealing connector. This sealing connector can not only effectively protect the optical fiber from bending damage and ensure the stable transmission of optical signals, but also has excellent sealing performance. Due to the drilling operation on the steel lining, the tight design of the sealing connector can effectively prevent hydrogen leakage from the lead wire, thus eliminating the potential hydrogen leakage risk while ensuring the optical signal transmission; the core component of the sealing connector is a metal rod, which penetrates the steel lining and the external structure. A hole with a diameter slightly larger than the optical fiber is reserved inside the metal rod to ensure the smooth passage of the optical fiber. The first section of the metal rod adopts a diameter-expanded design to increase the pressure-bearing area, the middle section is provided with a serrated structure to enhance the compressive performance, a trapezoidal polypropylene flexible material is nested between the first section and the middle section, and a triangular polypropylene flexible material is configured at the tail end. The optical fiber enters the first end of the metal rod, first evenly covers a layer of bentonite, and then lays a layer of polypropylene flexible material. The remaining space is filled by the water absorption and expansion of bentonite to achieve sealing. Subsequently, high-strength epoxy resin is injected into the interior, leaving the position of the tail end. After the epoxy resin solidifies, the same sealing structure is adopted at the tail end to form a multi-layer sealing barrier. Metal rings are configured at the inlet and outlet ends of the optical fiber to achieve dense fixation. The part of the metal rod extending out of the plug is sleeved with a special fixing piece, which is firmly fixed to the plug through expansion screws.

[0027] The second object of the present invention is to provide a preparation method for a leakage monitoring lead wire and a mitigation structure of a high-pressure hydrogen storage chamber as described above.

[0028] A preparation method for a leakage monitoring lead wire and a mitigation structure of a high-pressure hydrogen storage chamber, the construction steps include:

[0029] S1. Drill an advanced hole in the pre-excavated surrounding rock for pre-grouting;

[0030] S2. Excavate a rock chamber in the surrounding rock as required;

[0031] S3. Drive several anchor bolts and anchor cables into the surrounding rock, apply tensile stress to the anchor bolts and anchor cables with a jack, and lock the anchor bolts and anchor cables when the prestress design value is reached;

[0032] S4. Lay a 600-900 mm prestressed concrete stress-bearing layer on the inner side of the surrounding rock, and evenly add activated carbon when casting the mold;

[0033] S5. Weld the steel lining into shape;

[0034] S6. Place the formed filling layer on a layer of geotextile, then lay a layer of drag reduction film and a layer of geotextile to form a slip resistance and impermeability layer;

[0035] S7. Lay the slip resistance and impermeability layer outside the steel lining, evenly sprinkle water on the inner wall of the prestressed concrete stress-bearing layer and the outer wall of the steel lining, and then quickly push the slip resistance and impermeability layer and the steel lining together into the prestressed concrete stress-bearing layer;

[0036] S8. Open a hole from the steel lining to the outside of the chamber, and install a sealing connector at the opening.

[0037] S9. Enter the chamber through the gas transmission pipe, arrange a distributed optical fiber temperature measurement system at the inner wall groove of the steel lining, and seal the groove with a sealing material.

[0038] S10. Lead the optical fiber out through the reserved orifice of the sealing connector, connect it to the external optical fiber demodulator, and completely seal the connector with a sealing material.

[0039] S11. Inject high-pressure hydrogen into the steel lining for storage.

[0040] It should be noted that when hydrogen is injected in step S11, if the steel lining cracks and hydrogen leaks, bentonite and activated carbon in the slip resistance and leakage prevention layer can hinder the migration of hydrogen and adsorb hydrogen, achieving the effect of slowing down and even preventing hydrogen leakage.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) When high-pressure hydrogen leaks due to cracks in the steel lining, the temperature at the leakage point will drop suddenly. At this time, the distributed optical fiber temperature measurement system embedded in the inner wall groove of the steel lining can sensitively capture this temperature anomaly and quickly transmit this change in the form of an optical signal to the optical fiber demodulator. Subsequently, through the precise analysis of computer software, the specific location of the crack in the steel lining can be accurately located, providing precise guidance for timely repairing the crack and ensuring that the leakage problem is solved quickly and effectively.

[0043] (2) At the head and tail ends of the metal rod where the optical fiber enters, a layer of bentonite is first evenly covered. By injecting an appropriate amount of water into the bentonite, the bentonite quickly absorbs water and swells, forming a dense sealing layer, further improving the sealing effect of the sealing connector; the remaining space in the metal rod is filled with high-strength epoxy resin to ensure the sealing performance of the connector; between the head section and the middle section of the metal rod, a trapezoidal polypropylene flexible material is nested, and a triangular polypropylene flexible material is also configured at the tail end, which can maintain the sealing performance of the contact surface between the concrete and the sealing connector under high-pressure environment. When the metal rod undergoes a small deformation under high pressure, the polypropylene flexible materials in the middle and tail ends can be further compacted, thus achieving a more excellent sealing effect. The above structure forms multiple sealing barriers for the sealing connector.

[0044] (3) The optical fiber is tightly connected to the optical fiber demodulator outside the chamber through a carefully designed sealing connector. This sealing connector can not only effectively protect the optical fiber from bending damage and ensure the stable transmission of optical signals, but also has excellent sealing performance. Due to the drilling operation on the steel lining, the tight design of the sealing connector can effectively prevent hydrogen leakage from the lead wire, thus eliminating the potential hydrogen leakage risk while ensuring the optical signal transmission; the core component of the sealing connector is a metal rod, which penetrates the steel lining and the external structure. A hole with a diameter slightly larger than the optical fiber is reserved inside the metal rod to ensure the smooth passage of the optical fiber. The first section of the metal rod adopts an enlarged diameter design to increase the pressure-bearing area, the middle section is provided with a serrated structure to enhance the compressive performance, a trapezoidal polypropylene flexible material is nested between the first section and the middle section, and a triangular polypropylene flexible material is configured at the tail end. The optical fiber enters the first end of the metal rod, first evenly covers a layer of bentonite, and then lays a layer of polypropylene flexible material. The bentonite absorbs water and swells to fill the remaining space to achieve sealing. Subsequently, high-strength epoxy resin is injected into the interior, leaving the position of the tail end. After the epoxy resin solidifies, the same sealing structure is adopted at the tail end to form a multi-layer sealing barrier. Metal rings are configured at the inlet and outlet ends of the optical fiber to achieve dense fixation. The part of the metal rod extending out of the plug is sleeved with a special fixing piece, which is firmly fixed to the plug through expansion screws;

[0045] (4) The slip resistance and leakage prevention layer arranged between the stress-bearing layer and the steel lining adopts an innovative design of two layers of geotextiles sandwiching a filling layer, and a layer of drag reduction film is laid outside the filling layer. When high-pressure hydrogen leaks due to cracks in the steel lining, the activated carbon-modified bentonite in the filling layer can not only effectively hinder the migration of hydrogen through bentonite but also capture and adsorb hydrogen through activated carbon, thus significantly slowing down or even completely eliminating the further leakage of hydrogen; activated carbon is added to the stress-bearing layer during the injection molding process. Even if hydrogen enters the stress-bearing layer after breaking through the slip resistance and leakage prevention layer, the materials in the above two structures form two sealing barriers to slow down gas leakage;

[0046] (5) In addition, the tight wrapping of the two layers of geotextiles can prevent the filling layer from squeezing into the cracked stress-bearing layer, thereby avoiding excessive deformation of the steel lining due to the thinning of the filling layer and the cracking of the weld seam, further ensuring the comprehensive control of hydrogen leakage. Moreover, the low friction resistance characteristic of bentonite in the filling layer can effectively reduce the shear force transmitted from the steel lining to the stress-bearing layer to inhibit the shear failure of the stress-bearing layer and the formation of more leakage channels; the use of a prestressed concrete stress-bearing layer can effectively reduce the tensile stress transmitted from the high-pressure gas to the stress-bearing layer and prevent the stress-bearing layer from being damaged by tensile cracking to form more leakage channels. The above two structures form key measures to limit the damage and cracking of the stress-bearing layer 2 and enhance the overall sealing performance of the chamber;

[0047] (6) Advanced pre-grouting of the surrounding rock can enhance its strength; prestressed anchor bolts and prestressed cable bolts driven into the surrounding rock can resist the tensile stress transmitted by the high-pressure gas to the surrounding rock; the use of a prestressed concrete stress-bearing layer can resist part of the tensile stress transmitted by the high-pressure gas to the stress-bearing layer, thereby reducing the tensile stress of the stress-bearing layer and the surrounding rock. The above three measures can reduce the damage and cracking of the surrounding rock and are key measures to enhance the overall sealing performance of the chamber;

[0048] (7) The slip-proof and leak-proof layer consists of a bentonite filling layer in the middle and geotextiles on the inner and outer sides respectively close to the steel lining and the stress-bearing layer. Before pushing the slip-proof and leak-proof layer and the steel lining into the prestressed concrete stress-bearing layer together, water is evenly sprinkled on the inner wall of the stress-bearing layer and the outer wall of the steel lining. After pushing, the water enters the filling layer through the geotextile. Bentonite is a hydrous aluminum silicate mineral with strong water absorption and expansibility. When bentonite absorbs water and expands, it completely fills the construction gap between the slip-proof and leak-proof layer and the stress-bearing layer, directly solving the problem of construction joints and ensuring the integrity of the composite lining structure.

[0049] Therefore, the present invention discloses a leakage monitoring lead and mitigation structure for a high-pressure hydrogen storage chamber, which sequentially includes the surrounding rock, the stress-bearing layer, the slip-proof and leak-proof layer, and the steel lining sealed and wrapped from the outside to the inside. A distributed optical fiber temperature measurement system and a sealing connector are installed inside the steel lining. The distributed optical fiber temperature measurement system can capture temperature anomalies and accurately locate the positions of cracks in the steel lining, facilitating timely repair; the sealing connector ensures no hydrogen leakage at the optical fiber lead in the chamber, achieving leakage monitoring while ensuring the sealing performance; the surrounding rock restricts the damage and cracking of the surrounding rock and reduces leakage channels through prestressed anchor bolts, cable bolts, and the internal prestressed lining; the prestressed lining stress-bearing layer is arranged on the inner side of the surrounding rock, and a hydrogen storage material that can adsorb hydrogen is evenly added during the injection molding process. The bentonite slip-proof and leak-proof layer is arranged between the stress-bearing layer and the steel lining. The prestressed lining and the slip layer restrict the damage and cracking of the lining and reduce leakage channels; the hydrogen storage adsorption material and the bentonite slip layer in the lining can form multiple barriers to slow down gas leakage. Description of the Drawings

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0051] Figure 1 It is a schematic overall view of the leakage monitoring lead and mitigation structure for the high-pressure hydrogen storage chamber of the present invention;

[0052] Figure 2 It is a schematic overall view of the sealing connector of the present invention;

[0053] Figure 3It is a partial schematic diagram of the slip resistance and impermeability layer of the present invention, which successively includes a geotextile on the outside, a drag reduction film, a filling layer, an inner geotextile from outside to inside, and hydrogen storage materials distributed in the filling layer;

[0054] Figure 4 It is a schematic diagram of the internal cross-section of the steel lining of the present invention;

[0055] Figure 5 It is a schematic diagram of the external corridor of the chamber of the present invention;

[0056] Figure 6 It is a schematic diagram of the prestressed anchor rod driven into the surrounding rock of the present invention;

[0057] Figure 7 It is a partial schematic diagram of the positioning of the distributed optical fiber temperature measurement system for cracks in the steel lining of the present invention;

[0058] Among them, 1 - surrounding rock, 2 - stress layer, 3 - slip resistance and impermeability layer, 4 - steel lining, 5 - distributed optical fiber temperature measurement system, 6 - filling layer, 7 - geotextile, 8 - anchor rod, 9 - cable anchor, 10 - gas transmission pipe, 11 - ventilation valve, 12 - flange connection, 13 - optical fiber, 14 - sealing connection, 15 - optical fiber demodulator, 16 - hydrogen storage material, 17 - epoxy resin, 18 - plug, 19 - metal rod, 20 - polypropylene flexible material, 21 - bentonite, 22 - metal ring, 23 - expansion bolt, 24 - fixing piece, 25 - crack, 26 - drag reduction film. Specific embodiments

[0059] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0060] Here, the special term "embodiment", any embodiment described as "exemplary" does not have to be interpreted as superior to or better than other embodiments. For the performance index tests in the embodiments of this application, unless otherwise specified, the conventional test methods in the art are adopted. It should be understood that the terms described in this application are only used to describe specific embodiments and are not used to limit the content disclosed in this application.

[0061] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as those generally understood by those of ordinary skill in the technical field to which this application belongs; the test methods and technical means not otherwise specifically noted in this application refer to the experimental methods and technical means commonly adopted by those of ordinary skill in the art.

[0062] To better illustrate the content of this application, numerous specific details are given in the following specific embodiments. Those skilled in the art should understand that this application can be implemented without certain specific details. In the embodiments, some methods, means, instruments, devices, etc. that are well-known to those skilled in the art are not described in detail in order to highlight the gist of this application.

[0063] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "inner", "outer", "head", "tail", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation on the present invention.

[0064] On the premise of no conflict, the technical features disclosed in the embodiments of this application can be combined arbitrarily, and the obtained technical solutions belong to the content disclosed in the embodiments of this application.

[0065] The present invention discloses a leakage monitoring lead wire, a mitigation structure and a preparation method for a high-pressure hydrogen storage chamber, belonging to the technical field of underground gas storage. The leakage monitoring lead wire and mitigation structure for the high-pressure hydrogen storage chamber disclosed by the present invention sequentially include surrounding rock, a stress layer, a slip and impermeable layer, and a steel lining wrapped and sealed from the outside to the inside. A distributed optical fiber temperature measurement system and a sealing connector are installed inside the steel lining. The distributed optical fiber temperature measurement system can capture temperature anomalies and accurately locate the positions of cracks in the steel lining, facilitating timely repair; the sealing connector ensures that there is no hydrogen leakage at the optical fiber lead wire in the chamber, realizing leakage monitoring while ensuring the sealing performance; the surrounding rock restricts the damage and cracking of the surrounding rock and reduces the leakage channels through prestressed anchor bolts, anchor cables and the internal prestressed lining therein; the prestressed lining stress layer is arranged inside the surrounding rock, and a hydrogen storage material that can adsorb hydrogen is uniformly added during the injection molding process. The bentonite slip and impermeable layer is arranged between the stress layer and the steel lining. The prestressed lining and the slip layer restrict the damage and cracking of the lining and reduce the leakage channels; the hydrogen storage adsorption material and the bentonite slip layer in the lining can form multiple barriers to slow down gas leakage.

[0066] To better understand the present invention, the following embodiments are used to further specifically elaborate on the present invention, but it should not be construed as a limitation on the present invention. For some non-essential improvements and adjustments made by those skilled in the art based on the above-mentioned invention content, they are also considered to fall within the protection scope of the present invention.

[0067] Embodiment 1

[0068] Reference Figure 1 、 Figure 2 、 Figure 4 、 Figure 5 、 Figure 7, the monitoring part of the distributed optical fiber temperature measurement system 5 is located inside the steel lining 4, the optical fiber demodulator 15 is located outside the chamber, the optical fiber 13 is arranged at the reserved groove on the inner wall of the steel lining 4, the groove is sealed with epoxy resin 17, and the optical fiber 13 is led out of the chamber through the sealing connector 14 and connected to the optical fiber demodulator 15.

[0069] When cracks appear in the steel lining 4, resulting in high-pressure hydrogen leakage, the distributed optical fiber temperature measurement system 5 embedded in the inner wall of the steel lining 4 can quickly capture the abnormal temperature and transmit this change in the form of an optical signal to the optical fiber demodulator 15. Through computer software analysis, the crack position of the steel lining 4 can be accurately located, providing precise guidance for timely repair and ensuring the rapid and effective solution of the leakage problem; the optical fiber 13 is connected to the optical fiber demodulator 15 outside the chamber through the sealing connector 14. This connector not only protects the optical fiber 13 from bending damage and ensures the stable transmission of the optical signal, but also has excellent sealing performance. Drilling holes from the steel lining 4 to the outside of the chamber, the tight design of the sealing connector 14 effectively prevents hydrogen from leaking from the lead wire, ensuring the transmission of the optical signal while eliminating the risk of hydrogen leakage.

[0070] In a further optimized solution, the distributed optical fiber temperature measurement technology is based on its unique Raman scattering principle to achieve precise positioning of the leakage point. The Raman scattering signal is extremely sensitive to temperature changes around the optical fiber and is not easily interfered by other signals, which enables it to maintain high-precision temperature monitoring capabilities in complex environments. When cracks appear in the steel lining 4 and hydrogen leaks from the high-pressure area to the low-pressure area, due to the adiabatic expansion effect, hydrogen does work externally, resulting in a decrease in its internal energy and thus a temperature drop. This subtle temperature change is the key signal captured by the distributed optical fiber temperature measurement technology. As the theoretical foundation of the distributed optical fiber temperature measurement system, the optical time domain reflectometry technology accurately measures the distance by recording the time from the transmitted signal to the received signal, that is, calculating the time difference of the pulsed light from the laser to the acquisition end. The system efficiently collects the Raman backscattered light and calculates the distance of any point on the optical fiber from the receiving end according to the propagation time of the optical pulse in the optical fiber, thus achieving precise positioning in space. Combining with the optical time domain reflectometry technology, the system can efficiently collect and accurately position the temperature signal, ensuring real-time monitoring and accurate analysis of temperature changes in various complex environments.

[0071] In a further optimized solution, a continuous long-span optical fiber 13 is evenly arranged along the horizontal and vertical directions at a certain distance on the inner wall of the steel lining 4 by the distributed optical fiber temperature measurement system 5. This arrangement forms a high-density temperature monitoring network. As Figure 7As shown, a small curved square area on the inner wall of the steel lining 4 is selected. Since the selected area is relatively small, the curved surface can be approximately simplified as a plane for analysis. This simplification makes the capture of temperature changes more intuitive and accurate. When a crack occurs in this area and hydrogen leaks, the temperature at the leakage point will change suddenly, and this temperature change will propagate along the path of the optical fiber 13. Since the distances from the crack to the optical fibers 13 on the four sides are different, the amplitude of temperature change and time delay that each side of the optical fiber 13 can sense will also be different, and this difference provides unique signal characteristics for crack positioning. Through the precise analysis of the optical fiber demodulator 15, the specific position of the crack in the steel lining 4 can be accurately located, and this positioning accuracy provides reliable technical support for subsequent repair work.

[0072] In a further preferred solution, the temperature-sensitive optical fiber 13 is orderly arranged in the groove of the steel lining 4 and sealed with epoxy resin 17. This design can not only firmly fix the optical fiber 13, prevent it from being damaged during use, and effectively protect the integrity of the optical fiber 13, but also solve the problem of reduced compressive and shear strength caused by the reduced thickness at the groove of the steel lining 4. After the epoxy resin 17 cures, it forms a solid composite structure with the steel lining 4. Its high strength and rigidity characteristics enable effective dispersion and transmission of stress, thereby enhancing the compressive capacity of the steel lining 4. In addition, the sealing effect of the epoxy resin can also prevent the direct leakage of hydrogen when cracks occur in the groove part, ensuring the safety and reliability of the system.

[0073] In a further optimized solution, the optical fiber 13 is efficiently connected to the external optical fiber demodulator 15 through a precisely designed sealing connector 14. The core component of the sealing connector 14 is a metal rod 19, which penetrates the steel lining 4 and the external structure and is firmly connected through precisely machined holes. A hole with a diameter slightly larger than the optical fiber 13 is reserved in the metal rod 19 to ensure the smooth passage of the optical fiber 13.

[0074] The first section of the metal rod 19 adopts an expanded diameter design. Since the steel liner 4 is filled with high-pressure hydrogen, the expanded diameter design at the first end increases the area that bears the pressure, thereby reducing the stress concentration per unit area, effectively dispersing the impact force of high-pressure hydrogen on the sealing connector 14, and preventing the sealing connector 14 from fatigue or damage due to excessive stress. A row of serrated structures are set in the middle section. These serrated structures not only enhance the compressive performance of the metal rod 19, but also absorb external pressure through slight elastic deformation when under pressure, thereby improving the stability and reliability of the overall structure. In addition, the part of the metal rod 19 that extends out of the plug 18 is also covered with a special fixing 24, which is firmly fixed to the plug 18 by an expansion screw 23. The use of the expansion screw 23 ensures the close connection between the fixing 24 and the plug 18, further improving the stability of the overall structure. The expanded diameter design, the synergistic effect of the serrated structure and the tail end fixing enable the sealing connector 14 to effectively disperse and absorb pressure when subjected to high pressure, ensuring the long-term stable operation of the sealing connector 14.

[0075] A circle of trapezoidal polypropylene flexible material 20 is nested between the first section and the middle section of the metal rod 19, and a circle of triangular polypropylene flexible material 20 is also configured at the tail end. Polypropylene flexible material has excellent pressure resistance, chemical corrosion resistance and good flexibility, and can maintain stable sealing performance under high pressure environment. When the metal rod 19 is slightly deformed under high pressure, the polypropylene flexible material 20 in the middle and tail ends can be further compacted, thereby achieving a more excellent sealing effect.

[0076] At the head and tail ends of the optical fiber 13 entering the metal rod 19, a layer of bentonite 21 is first evenly covered. Bentonite is a clay material with high expansion properties. It can expand greatly in volume after absorbing water, thereby effectively filling tiny gaps. A layer of polypropylene flexible material 20 is then laid on it. By injecting an appropriate amount of water into the bentonite 21, the bentonite 21 quickly absorbs water and expands to form a dense sealing layer, which further improves the compacting effect of the sealing connector. To further enhance the sealing effect, high-strength epoxy resin 17 is injected into the remaining space in the metal rod 19. Epoxy resin has excellent bonding properties, mechanical properties and chemical stability, and can work stably for a long time in high temperature, high pressure and corrosive environments. The injection of epoxy resin 17 forms multiple sealing barriers to ensure the absolute sealing of the connector. Metal rings 22 are configured at the inlet and outlet ends of the optical fiber 13. These metal rings are precisely processed to ensure a close fit with the optical fiber, thereby achieving a dense fixation of the optical fiber. The structural design of the metal ring 22 ensures stability in a high-pressure environment and prevents the optical fiber from being loosened or damaged due to vibration or other external forces.

[0077] A high-pressure hydrogen storage chamber leakage monitoring lead and mitigation structure and preparation method, the construction steps include:

[0078] S1. Before excavating the surrounding rock 1, drill advanced holes at the pre-excavation site, and inject pressure grout into the holes through the grouting equipment to improve the overall strength of the surrounding rock 1;

[0079] S2. After the grout solidifies, excavate the rock chamber on the surrounding rock 1 according to the construction plan;

[0080] S3. Drill precise holes in the excavated surrounding rock 1, slowly push the anchor bolts 8 and cable bolts 9 into the holes to ensure accurate positioning, inject the grouting material with precise proportion through the grouting pump to ensure that the holes are completely filled, use a high-precision tension jack to provide tension to the anchor bolts 8 and cable bolts 9, lock the anchor bolts 8 and cable bolts 9 after reaching the design prestress, and use high-strength cement mortar for strict hole sealing treatment to ensure stability and long-term protection;

[0081] S4. Lay the stress-bearing layer 2 with a thickness of 600 - 900 mm on the inner side of the surrounding rock 1. According to the specific design mold required by the construction plan, arrange the steel mesh, pre-tension the steel bars by the pre-tensioning method, and then pour high-strength concrete. Activated carbon is evenly added during the pouring of the mold;

[0082] S5. The steel lining 4 is welded according to the construction plan, one end is completely sealed, and the other end is hermetically welded to the gas transmission pipe 10;

[0083] S6. The slip resistance and seepage prevention layer 3 consists of the middle filling layer 6, the drag reduction film 26 outside the filling layer 6 and the geotextiles 7 on both sides. Activated carbon is evenly added to the bentonite. First, lay a layer of geotextile 7, then evenly lay about 10 - 15 mm of bentonite, and finally lay another layer of drag reduction film 26 and a layer of geotextile 7, and compact them tightly;

[0084] S7. Lay the slip resistance and seepage prevention layer 3 outside the steel lining 4, evenly sprinkle water on the inner wall of the prestressed concrete stress-bearing layer 2 and the outer wall of the steel lining 4, and then quickly push the slip resistance and seepage prevention layer 3 and the steel lining 4 together into the prestressed concrete stress-bearing layer 2;

[0085] S8. Drill a hole through the plug from the steel lining 4 to the outside corridor, and install the pre-designed sealing connector 14 at the hole opening;

[0086] S9. Arrange the distributed optical fiber temperature measurement system 5 in the inner wall groove of the steel lining 4, continuously arrange the optical fiber 13 along the groove, and completely seal the groove with the sealing material;

[0087] S10. Lead out the optical fiber 13 through the reserved hole of the sealing connector 14, connect it to the external optical fiber demodulator 15, and completely seal the connector with the sealing material.

[0088] S11. Inject high-pressure hydrogen into the steel lining 4 through the gas transmission pipe 10 for storage.

[0089] Example 2

[0090] Reference Figure 1 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 ,The present invention discloses a leakage monitoring lead wire and a mitigation structure for a high-pressure hydrogen storage chamber, which successively include a surrounding rock 1, a stress-bearing layer 2, a sliding resistance and impermeability layer 3, and a steel liner 4 sealed and wrapped from outside to inside; anchor bolts 8 and cable bolts 9 are driven into the surrounding rock 1; the stress-bearing layer 2 is a prestressed concrete stress-bearing layer; one end of the steel liner 4 is sealed, and the other end is connected to a gas transmission pipe 10. An air vent valve 11 is installed near the tail end of the gas transmission pipe 10, and the tail end is blocked by a flange connector 12.

[0091] The sliding resistance and impermeability layer 3 provided between the stress-bearing layer 2 and the steel liner 4 adopts an innovative design of sandwiching a filling layer 6 with two layers of geotextiles 7, and a layer of drag reduction film 26 is laid outside the filling layer 6. The hydrogen storage material 16 is evenly distributed in the stress-bearing layer 2 and the filling layer 6. When the steel liner 4 leaks high-pressure hydrogen due to cracks, the activated carbon modified bentonite in the filling layer 6 can not only effectively hinder the migration of hydrogen through bentonite but also capture and adsorb hydrogen through activated carbon, thereby significantly slowing down or even completely preventing further leakage of hydrogen. In addition, the tight wrapping of the two layers of geotextiles 7 can prevent the filling layer 6 from squeezing into the stress-bearing layer 2, thereby avoiding excessive deformation of the steel liner 4 caused by the thinning of the filling layer and the cracking of the weld, further ensuring the comprehensive control of hydrogen leakage. Moreover, the low friction resistance characteristic of bentonite in the filling layer 6 can effectively reduce the shear force transmitted from the steel liner 4 to the stress-bearing layer 2 to inhibit the shear failure of the stress-bearing layer 2 and the formation of more leakage channels in the stress-bearing layer 2.

[0092] In a further optimized solution, the filling layer 6 uses activated carbon modified bentonite as the filling material. Bentonite is a hydrous aluminum silicate mineral with a very low permeability. When cracks occur on the steel liner 4 and hydrogen leaks, bentonite will inhibit hydrogen leakage, and the activated carbon in bentonite can further utilize its own large specific surface area advantage to adsorb the leaked hydrogen, thereby significantly slowing down or even completely preventing further leakage of hydrogen.

[0093] For a further optimized solution, the slip resistance and seepage prevention layer 3 consists of a filling layer 6 in the middle and geotextiles 7 on both sides. One layer of geotextile 7 is arranged inside the prestressed concrete stress-bearing layer 2, and the other layer of geotextile 7 is arranged outside the steel lining 4. The tight wrapping of the two layers of geotextiles 7 can not only make the filling layer 6 dense and closely adhere to the steel lining 4, facilitating the pushing into the prestressed concrete stress-bearing layer 2. In addition, the geotextile 7 has water permeability and can transmit moisture into the filling layer 6. Before pushing the slip resistance and seepage prevention layer 3 and the steel lining 4 into the prestressed concrete stress-bearing layer 2 together, water is evenly sprinkled on the inner wall of the stress-bearing layer 2 and the outer wall of the steel lining 4. After pushing, the water enters the filling layer 6 through the geotextile 7. Bentonite is a hydrous aluminum silicate mineral with strong water absorption and expansibility. When bentonite absorbs water and expands, it completely fills the construction gap existing between the slip resistance and seepage prevention layer 3 and the stress-bearing layer 2, directly solving the problem of construction joints.

[0094] For a further optimized solution, activated carbon is evenly added to the filling layer 6 and the prestressed concrete stress-bearing layer 2. Activated carbon is a highly porous material with a very large specific surface area. Its surface consists of micropores, mesopores, and macropores, and these pores provide a large number of adsorption sites. The adsorption of hydrogen by activated carbon is mainly based on physical adsorption. There is a van der Waals force between the hydrogen molecule and the carbon atoms on the surface of the activated carbon, and this force enables the hydrogen molecule to adhere inside the pores of the activated carbon. If hydrogen overflows from the crack, it is first adsorbed by the activated carbon in the filling layer 6. If there is still some hydrogen breaking through the slip resistance and seepage prevention layer 3, it will still be further adsorbed by the activated carbon in the prestressed concrete stress-bearing layer 2 when passing through it, blocking the leakage of hydrogen through a double defense line.

[0095] For a further optimized solution, the filling layer 6 uses bentonite with low friction resistance characteristics, which can reduce the shear friction resistance transmitted from the steel lining 4 to the stress-bearing layer 2. In addition, the stress-bearing layer 2 adopts a prestressed concrete stress-bearing layer 2, which can resist the tensile stress load transmitted by high-pressure hydrogen to the concrete part through prestress. Eventually, the tensile stress and shear stress of the stress-bearing layer 2 are reduced, preventing the stress-bearing layer 2 from being damaged by tensile cracks and forming more leakage channels. The above structures of the filling layer 6 and the prestressed stress-bearing layer 2 form key measures to limit the damage and cracking of the stress-bearing layer 2 and enhance the overall sealing performance of the chamber.

[0096] For a further optimized solution, the surrounding rock 1 is pre-grouted in advance. By injecting grout, the fissures and pores in the surrounding rock 1 are filled, increasing the overall strength and stiffness of the surrounding rock 1, improving its ability to resist the load transmitted by high-pressure hydrogen to the surrounding rock 1, reducing the deformation and damage of the surrounding rock 1, and preventing cave-ins. The grout fills the fissures in the surrounding rock 1, forming a sealing barrier and improving the anti-seepage performance of the surrounding rock 1 to ensure construction safety.

[0097] For a further optimized solution, a number of bolts 8 and cable bolts 9 are driven into the surrounding rock 1. The bolts 8 and cable bolts 9 enhance the stability of the surrounding rock 1 by applying prestress. The bolt 8 is anchored in the surrounding rock 1 by its rod body, and a tensile force is applied to the bolt 8 by a jack, causing the bolt 8 to generate prestress, thereby applying pressure to the surrounding rock 1, making the bolt 8 and the rock mass form an integral body, enhancing the integrity and stability of the surrounding rock 1. The bolt 8 can increase the tensile strength and shear strength of the surrounding rock 1, effectively control the deformation of the surrounding rock 1, and prevent the surrounding rock 1 from cracking and slipping. The cable bolt 9 is usually composed of multiple strands of steel strands. By fixing the cable bolt 9 in the surrounding rock 1 and applying a tensile force with a jack, the cable bolt 9 generates prestress and applies pressure to the surrounding rock 1. The cable bolt 9 is suitable for the reinforcement of rock masses with large spans and large areas, can provide greater anchoring force and reinforcement effect, improve the overall stability of the surrounding rock 1, and prevent large-scale deformation and damage of the surrounding rock 1. In addition, the cable bolt 9 can be flexibly arranged according to the specific conditions of the surrounding rock 1. In summary, advanced pre-grouting of the surrounding rock 1 can enhance the strength of the surrounding rock 1; driving bolts 8 and cable bolts 9 into the surrounding rock 1 can resist the tensile stress transmitted by the high-pressure gas to the surrounding rock 1; using the prestressed concrete stress-bearing layer 2 can resist part of the tensile stress transmitted by the high-pressure gas to the stress-bearing layer 2, thereby reducing the tensile stress of the stress-bearing layer 2 and the surrounding rock 1; the above three measures can reduce the damage and cracking of the surrounding rock 1 and enhance the overall sealing performance of the chamber.

[0098] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A leakage monitoring lead and mitigation structure for a high-pressure hydrogen storage chamber, characterized in that, It includes a surrounding rock (1), a stress-bearing layer (2), a slip resistance and impermeability layer (3), and a steel liner (4) that is hermetically wrapped from outside to inside. Among them, anchors (8) and cable bolts (9) are driven into the surrounding rock (1); the stress-bearing layer (2) is a prestressed concrete stress-bearing layer; the slip resistance and impermeability layer (3) is composed of a middle filling layer (6) and geotextiles (7) on both the inner and outer sides; among them, the outer geotextile (7) is arranged on the inner side of the stress-bearing layer (2), and a drag reduction film (26) is arranged between the outer geotextile (7) and the filling layer (6); the inner geotextile (7) is arranged on the outer side of the steel liner (4); the steel liner (4) is connected to an external gas transmission pipe (10), a ventilation valve (11) is installed near the outer end of the gas transmission pipe (10), and the outermost end is sealed with a flange connection (12); It also includes: a distributed optical fiber temperature measurement system (5) with a monitoring part located inside the steel liner (4), an optical fiber demodulator (15) located outside the chamber, and an optical fiber (13) arranged at a reserved groove on the inner wall of the steel liner (4) and led out of the chamber through a sealing connection (14) to be connected to the optical fiber demodulator (15); hydrogen storage materials (16) are evenly distributed in the stress-bearing layer (2) and the filling layer (6); the optical fiber (13) is a single-mode temperature-sensing optical fiber, and the part where the optical fiber enters and exits of the sealing connection (14) and the reserved groove on the inner wall of the steel liner (4) are sealed with a sealing material; the sealing material includes one or a combination of polypropylene flexible materials (20), bentonite (21), and epoxy resin (17); the sealing connection (14) includes a metal rod (19), and a hole for wrapping the optical fiber (13) is arranged inside the metal rod (19); the first section of the hole is enlarged in diameter, the middle section is serrated, a trapezoidal polypropylene flexible material (20) is nested between the first section and the middle section, and a triangular polypropylene flexible material (20) is arranged at the tail end; after the optical fiber (13) is arranged, bentonite (21) and polypropylene flexible materials (20) are covered at the head and tail ends of the metal rod (19), and epoxy resin (17) is injected into the internal empty part.

2. The leakage monitoring lead and mitigation structure of the high-pressure hydrogen storage chamber according to claim 1, characterized in that, The anchor (8) is a prestressed anchor, and the cable bolt (9) is a prestressed cable bolt.

3. The leakage monitoring lead and mitigation structure for a high-pressure hydrogen storage chamber according to claim 1, characterized in that Metal rings (22) are configured at the head and tail ends of the optical fiber (13) for dense fixation, a fixing part (24) is welded to the part of the metal rod (19) protruding from the plug (18), and it is fixed to the plug (18) through an expansion screw (23).

4. The preparation method of the leakage monitoring lead and mitigation structure for the high-pressure hydrogen storage chamber according to claim 1, characterized in that, The construction steps include: S1. Drill an advanced hole in the pre-excavated surrounding rock (1) for pre-grouting; S2. Excavate a rock chamber in the surrounding rock (1) as needed: S3. Drive several anchors (8) and cable bolts (9) into the surrounding rock (1), apply tensile stress to the anchors (8) and cable bolts (9) with a jack, and lock the anchors (8) and cable bolts (9) when the prestress design value is reached; S4. Lay a 600 - 900 mm prestressed concrete stress-bearing layer (2) on the inner side of the surrounding rock (1), and evenly add activated carbon during mold injection; S5. Weld the steel liner (4) into shape; S6. The slip resistance and impermeability layer (3) consists of a middle filling layer (6), a drag reduction film (26) outside the filling layer (6), and geotextiles (7) on both sides. The filling layer (6) is bentonite added with activated carbon. First, lay a layer of geotextile (7), then evenly lay 10 - 15 mm of bentonite containing activated carbon, and finally lay another layer of drag reduction film (26) and a layer of geotextile (7), and press tightly and compactly. S7. Lay the slip resistance and impermeability layer (3) outside the steel lining (4). Evenly sprinkle water on the inner wall of the prestressed concrete stress layer (2) and the outer wall of the steel lining (4), and then quickly push the slip resistance and impermeability layer (3) and the steel lining (4) together into the prestressed concrete stress layer (2). S8. Open a hole from the steel lining (4) to the outside of the chamber, and install a sealing connector (14) at the opening. S9. Enter the chamber through the gas transmission pipe (10). Arrange a distributed optical fiber temperature measurement system (5) at the inner wall groove of the steel lining (4), and seal the groove with a sealing material. S10. Lead out the optical fiber (13) through the reserved hole of the sealing connector (14), connect it to the external optical fiber demodulator (15), and completely seal the connector with a sealing material. S11. Inject high-pressure hydrogen into the steel lining (4) through the gas transmission pipe (10) for storage.

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