Formwork-free continuously-formed compressed air energy storage artificial underground gas storage sealing structure and construction method thereof

Abstract

The invention discloses a template-free continuously-formed compressed air energy storage artificial underground gas storage sealing structure and a construction method thereof, and relates to the field of underground gas storage. The sealing structure comprises a leveling layer, a sliding layer, a lining layer and a flexible sealing layer which are sequentially arranged from outside to inside. The leveling layer provides a flat and stable foundation for the internal structure, and the slip layer is configured to disperse stress concentration induced by surrounding rock cracking through self shear deformation; when the gas storage operates, surrounding rock is prone to cracking due to high pressure, the stress concentration state can be effectively relieved through the sliding layer, the lining layer and the sealing layer are protected, and the crack resistance and durability of the structure are improved; the lining layer provides structural support, the flexible sealing layer is used for ensuring high airtightness, and the overall stability and reliability of the sealing structure of the gas storage are enhanced. According to the construction method, a continuous propelling mode is adopted, a traditional formwork and parting technology is omitted, the construction process is simplified, sealing hidden dangers caused by construction joints are reduced, and the construction efficiency and the structural integrity are improved.

Description

Technical Field

[0001] This invention relates to the field of underground gas storage facilities, specifically to a template-free, continuously formed sealing structure for an artificial underground gas storage facility for compressed air energy storage and its construction method. Background Technology

[0002] Compressed air energy storage (CAES) is an important long-term energy storage technology supporting new power systems. Artificial underground gas storage facilities have become key gas storage facilities due to their flexible site selection and controllable volume. These gas storage facilities need to withstand high pressure of 10-16MPa for a long time, and their lining structure faces severe challenges such as surrounding rock cracking, temperature and pressure cycling and interface stress concentration.

[0003] Related technologies mainly employ a combination of rigid concrete lining and internal sealing layer, or a combination of segmented lining and flexible expansion joints for artificial underground gas storage. Such combined structures often rely on formwork for joint construction, which can easily lead to structural weaknesses. Under long-term operation at high internal pressure, the structure of artificial underground gas storage will develop circumferential cracks. The structure is unable to effectively buffer the local stress concentration caused by the cracks, resulting in cracking of the concrete lining, puncture or voiding of the sealing layer, and ultimately causing the gas storage to leak and fail. Summary of the Invention

[0004] In view of this, the present invention provides a template-free, continuously formed sealing structure for an artificial underground gas storage facility for compressed air energy storage and its construction method, in order to solve the problems mentioned in the background art.

[0005] In a first aspect, the present invention provides a template-free, continuously formed sealing structure for an artificial underground gas storage facility for compressed air energy storage, comprising a leveling layer, a sliding layer, a lining layer, and a flexible sealing layer arranged sequentially from the outside to the inside.

[0006] The leveling layer is suitable for covering the excavation surface of the surrounding rock;

[0007] The slip layer is disposed on the inner wall surface of the leveling layer;

[0008] The lining layer is disposed on the inner wall surface of the sliding layer;

[0009] The flexible sealing layer is sealed on the inner wall surface of the lining layer;

[0010] The slip layer is configured to absorb displacement disturbances induced by cracks in the surrounding rock through its own shear deformation, thereby dispersing stress transmission to the lining layer.

[0011] Beneficial effects: The sealing structure consists of a leveling layer, a sliding layer, a lining layer, and a flexible sealing layer, arranged from the outside in, to establish a multi-layered collaborative system. The leveling layer provides a flat and stable foundation for the internal structure. The sliding layer is configured to disperse stress concentration on the lining caused by surrounding rock cracking through its own shear deformation. During the operation of the gas storage facility, the surrounding rock is prone to cracking under high pressure. If the displacement and stress concentration caused by the cracks are directly transmitted to the lining layer, it will lead to cracking of the lining layer and sealing failure. The sliding layer can effectively alleviate the stress concentration by dispersing the concentrated stress through its own flexible deformation, protecting the lining layer and the sealing layer, and improving the crack resistance and durability of the structure. The lining layer provides structural support, and the flexible sealing layer ensures high airtightness. The cooperation of each layer significantly enhances the overall stability and reliability of the gas storage facility's sealing structure, effectively improving its ability to resist complex working conditions such as surrounding rock deformation, high pressure, and temperature changes.

[0012] In some embodiments, the slip layer is a sprayed material, and the slip layer is configured as one of a modified bitumen-based elastomer, an EPDM rubber composite membrane, or a self-adhesive polymer waterproofing pad.

[0013] Beneficial effects: These materials all possess the characteristics of low modulus, high elongation, and reliable shear resistance. The low modulus allows the slip layer to deform more easily under stress, effectively buffering stress. The high elongation ensures that it will not easily break during the deformation of the surrounding rock, continuously playing a role in dispersing stress transfer. The shear resistance ensures the integrity of the slip layer's structure under complex stress conditions, thereby comprehensively improving the performance of the slip layer in the sealing structure of gas storage facilities. In addition, these materials can be applied using different construction techniques such as hot-melt spraying or wet-laying of roll materials, allowing for the selection of the most suitable method for slip layer construction under different construction environments and cross-sectional conditions. This greatly improves the flexibility and adaptability of construction, contributing to improved project quality and efficiency.

[0014] In some embodiments, the thickness of the slip layer is 5mm-20mm.

[0015] Beneficial effects: Setting the thickness of the slip layer to 5mm-20mm ensures that the slip layer can effectively absorb the displacement disturbance induced by the surrounding rock cracks and disperse stress transmission. It also achieves a good balance between material usage and engineering costs, avoiding the situation where the thickness is too thin, which would prevent it from fully exerting its role in dispersing stress and buffering deformation. It also avoids the situation where the slip layer is too thick, which would increase material costs and affect the overall mechanical properties of the structure.

[0016] In some embodiments, the shear stress of the slip layer satisfies the following model:

[0017]

[0018] Where τ(x) is the shear stress within the slip layer; G is the shear modulus of the slip layer material; du(x) / dx is the displacement gradient of the slip layer along the x-direction; and t is the thickness of the slip layer.

[0019] Beneficial effects: This scheme can provide a theoretical basis for the design and material selection of slip layers; designers can select materials with low shear modulus G, reasonably set the thickness t, and combine the displacement gradient du(x) / dx under actual working conditions to accurately control the magnitude of shear stress in the slip layer, ensuring that it works effectively within the design range, better play the role of dispersing stress transfer and protecting the inner structure, and also facilitate mechanical analysis and optimization of the structure.

[0020] In some embodiments, the leveling layer is a cement mortar or fine aggregate concrete layer with a thickness of 20mm-100mm; the leveling layer is spray-formed onto the excavated surface of the surrounding rock to smooth the base surface and seal the pores of the surrounding rock.

[0021] Beneficial effects: The main function of the leveling layer is to smooth the uneven excavated surface of the surrounding rock, allowing the subsequent slip layer to be laid on a uniform and flat base surface, which helps to improve the bonding performance and overall stability of the slip layer. At the same time, cement mortar or fine aggregate concrete can seal the pores of the surrounding rock, reduce initial seepage, and prevent groundwater or other impurities from adversely affecting subsequent structural layers, providing a good foundation for the entire gas storage sealing structure.

[0022] In some embodiments, the lining layer is a concrete layer incorporating synthetic fibers, and the tensile strain of the lining layer is ≥3%.

[0023] Beneficial effects: The lining layer is made of concrete mixed with synthetic fibers, making it a high-ductility concrete. Under stress, it can form numerous fine cracks, unlike ordinary concrete which is prone to single large cracks. It can effectively disperse stress and avoid structural integrity failure caused by a single large crack. When the internal pressure of the gas storage facility changes or is affected by the deformation of the surrounding rock, the high-ductility concrete lining layer can maintain the load-bearing capacity of the structure through its own multi-crack characteristics, providing a stable support interface for the flexible sealing layer, while improving the crack resistance and durability of the entire lining structure.

[0024] In some embodiments, the synthetic fiber is polyvinyl alcohol or polyethylene fiber.

[0025] Beneficial effects: The synthetic fibers selected are polyvinyl alcohol (PVA) or polyethylene (PE) fibers. These fibers have high strength and high elastic modulus, and their incorporation into concrete can significantly improve the mechanical properties of concrete. During the stress process of concrete, the fibers bear part of the tensile stress through bridging, limit the excessive opening of individual cracks, and promote stress transfer to adjacent areas, forming a controlled, dense, multi-crack distribution to enhance the ductility of concrete.

[0026] In some embodiments, the thickness of the lining layer is 100-250 mm.

[0027] Beneficial effects: This thickness range design ensures that the lining layer has sufficient load-bearing capacity without causing material waste or affecting other structural properties due to excessive thickness. It ensures that the lining layer can stably perform its functions of bearing pressure and dispersing stress under different working conditions.

[0028] In some embodiments, the flexible sealing layer is a polyurea, polyurethane, or butyl rubber coating with a thickness of 1-5 mm, and the temperature resistance range of the flexible sealing layer is -40℃ to 100℃.

[0029] Beneficial effects: This type of material has excellent adhesion, anti-aging properties, and airtightness; high adhesion ensures a tight bond between the sealing layer and the lining layer, making it less prone to falling off; anti-aging properties ensure that the sealing layer maintains stable performance during long-term use; the temperature resistance range is set to -40℃ to 100℃, and the wide temperature resistance range can adapt to temperature changes during the operation of the gas storage facility to meet the gas storage requirements; excellent airtightness is the key to ensuring the sealing effect of the gas storage facility, which can effectively prevent compressed air leakage and ensure the efficient and stable operation of the gas storage facility.

[0030] In some embodiments, the leveling layer, sliding layer, lining layer and flexible sealing layer are sealed and abutted against each other, and are nested together to form a continuous closed annular structure.

[0031] Beneficial effects: The leveling layer, sliding layer, lining layer, and flexible sealing layer are sealed and interlocked to form a continuous closed ring structure. This design effectively avoids gas leakage paths and greatly improves the airtightness of the gas storage facility. Simultaneously, the continuous closed ring structure enhances the collaborative working ability between the layers, enabling the entire sealing structure to withstand external forces such as pressure, temperature changes, and surrounding rock deformation as a whole, improving the structural integrity and stability, and ensuring the long-term safe operation of the gas storage facility.

[0032] Secondly, the present invention also provides a construction method for a template-free, continuously formed sealing structure of an artificial underground gas storage facility for compressed air energy storage, comprising the following steps:

[0033] S1. Spray cement mortar or fine aggregate concrete onto the excavated surface of the surrounding rock to form a leveling layer with a thickness of 20mm-100mm, and then smooth the surface.

[0034] S2. Lay a sliding layer with a thickness of 5mm-20mm on the inner surface of the leveling layer by hot melt spraying or wet roll bonding process.

[0035] S3. Continuously spray concrete on the inner surface of the slip layer to form a lining layer with a thickness of 100mm-250mm;

[0036] S4. After the lining layer has been cured to the required standard, a flexible sealing material is sprayed onto its inner surface to form a flexible sealing layer with a thickness of 1-5mm.

[0037] Beneficial effects: This construction method involves spraying cement mortar or fine aggregate concrete onto the excavated rock face to form a leveling layer, then laying a slip layer on the inner surface of the leveling layer, followed by spraying concrete onto the inner surface of the slip layer to form a lining layer, and finally spraying a flexible sealing layer after the lining layer has cured to the required standard. The entire construction process adopts a continuous advancement method, with each step closely connected, eliminating the traditional formwork and jointing process, greatly simplifying the construction process, shortening the construction cycle, reducing sealing risks caused by construction joints, and improving construction efficiency and structural integrity. This construction method can ensure the performance of the entire gas storage sealing structure, giving it excellent performance in terms of sealing, stability, and durability. Attached Figure Description

[0038] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0039] Figure 1 This is a circumferential cross-sectional view of the sealing structure of the template-free continuously formed artificial underground gas storage tank for compressed air energy storage according to an embodiment of the present invention;

[0040] Figure 2 This is a construction schematic diagram of the template-free, continuously formed sealed artificial underground gas storage structure for compressed air energy storage, according to an embodiment of the present invention.

[0041] Figure 3 This is a construction flowchart of the template-free continuously formed sealed structure of the artificial underground gas storage for compressed air energy storage according to an embodiment of the present invention.

[0042] Figure 4 This is a schematic diagram of the crack diffusion mechanism provided in an embodiment of the present invention.

[0043] Explanation of reference numerals in the attached figures:

[0044] 101. Leveling layer; 102. Sliding layer; 103. Lining layer; 104. Flexible sealing layer. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Currently, the sealing structures for artificial gas storage facilities mostly employ rigid concrete lining with internal sealing layers or segmented lining with flexible expansion joints. These structures have problems in mitigating issues such as cracking of the surrounding rock and lining, and voids in the sealing layer.

[0047] In related technologies, some design schemes use rigid fiberglass or multi-layer plate structures as sealing layers. However, rigid seals cannot deform in tandem with the concrete lining, and stress concentration easily occurs at circumferential tensile crack locations, leading to gas storage system failure. Some design schemes use high-strength steel for sealing. Although steel linings have relatively good load-bearing capacity, they are difficult to process, weld, and install, have long construction cycles, are unsuitable for continuous lining in large-section underground spaces, and also suffer from problems such as inability to deform in tandem with the concrete lining. Some design schemes propose sliding or movable joint structures to release tensile stress in the concrete, but these require the combination of multiple components, increasing construction complexity and resulting in numerous splicing joints, which are detrimental to overall sealing and durability. Attempts have been made to introduce flexible deformable layers, but most structures still rely on cast-in-place formwork, making axial joints unavoidable. Additionally, circumferential joints are set to release circumferential stress, but this structure is complex to construct and difficult to guarantee long-term reliability.

[0048] Therefore, traditional structural systems are difficult to adapt to the working requirements of structural joints. Under high internal pressure, the surrounding rock and lining structure are at risk of cracking. Traditional structural systems are prone to stress concentration at the crack locations and circumferential tensile crack locations, leading to the failure of the gas storage system. In addition, the existing gas storage construction schemes are complex: most schemes still rely on formwork casting, which has weaknesses such as structural joints, construction joints, and expansion joints, resulting in many operational hazards and low construction efficiency.

[0049] To address the aforementioned problems, this invention proposes a template-free, continuously formed sealing structure for an artificial underground gas storage facility and its construction method. This sealing structure comprises a leveling layer, a sliding layer, a lining layer, and a flexible sealing layer. The sliding layer is a key component; by introducing a low-modulus, finite-thickness flexible medium, it generates controlled sliding when mechanically transmitting disturbance displacement, actively releasing the shear stress concentrated by circumferential cracks. The lining layer possesses multi-crack dispersion and ductile energy absorption capabilities, further homogenizing the stress field and preventing large crack penetration. The flexible sealing layer, on the stable attachment support interface, undertakes the final airtight sealing function.

[0050] This invention constructs a synergistic design of stress buffering, ductile pressure bearing and flexible sealing. The whole process adopts a spraying technology to achieve seamless, fast and continuous construction, which significantly improves the crack resistance, sealing reliability and construction efficiency of the structure, and has broad engineering adaptability and promotion and application value.

[0051] The following is combined Figures 1 to 3 The following describes embodiments of the present invention.

[0052] According to embodiments of the present invention, in one aspect, a template-free, continuously formed sealing structure for an artificial underground gas storage facility for compressed air energy storage is provided, see [link to documentation]. Figure 1 , Figure 1 This is a circumferential cross-sectional view of the sealing structure of a template-free continuously formed artificial underground gas storage tank for compressed air energy storage according to an embodiment of the present invention. The sealing structure includes a leveling layer 101, a sliding layer 102, a lining layer 103, and a flexible sealing layer 104 arranged sequentially from the outside to the inside. The leveling layer 101 is suitable for covering the excavation surface of the surrounding rock. The sliding layer 102 is disposed on the inner wall surface of the leveling layer 101. The lining layer 103 is disposed on the inner wall surface of the sliding layer 102. The flexible sealing layer 104 is sealed on the inner wall surface of the lining layer 103.

[0053] In this embodiment, the slip layer 102 is configured to absorb the displacement disturbance induced by the surrounding rock cracks through its own shear deformation, so as to disperse the stress transmission to the lining layer 103.

[0054] The sealing structure provided in this embodiment comprises a leveling layer 101, a sliding layer 102, a lining layer 103, and a flexible sealing layer 104, arranged from the outside in, to establish a multi-layered collaborative system. The leveling layer 101 provides a flat and stable foundation for the internal structure. The sliding layer 102 is configured to disperse stress concentration on the lining caused by surrounding rock cracking through its own shear deformation. During the operation of the gas storage facility, the surrounding rock is prone to cracking under high pressure. If the displacement and stress concentration caused by the cracks are directly transmitted to the lining layer 103, it will lead to cracking of the lining layer 103 and sealing failure. The sliding layer 102 can effectively alleviate the stress concentration by dispersing the concentrated stress through its own flexible deformation, protecting the lining layer 103 and the sealing layer, and improving the crack resistance and durability of the structure. The lining layer 103 provides structural support, and the flexible sealing layer 104 ensures high airtightness. The cooperation of each layer significantly enhances the overall stability and reliability of the gas storage facility's sealing structure, effectively improving its ability to resist complex working conditions such as surrounding rock deformation, high pressure, and temperature changes.

[0055] In a specific embodiment, the leveling layer 101 is set as a cement mortar or fine aggregate concrete layer with a thickness of 20mm-100mm. The leveling layer 101 is spray-formed onto the excavated surface of the surrounding rock to smooth the base surface and seal the pores of the surrounding rock. The main function of the leveling layer 101 is to smooth the uneven excavated surface of the surrounding rock, so that the subsequent sliding layer 102 can be laid on a uniform and flat base surface, which helps to improve the bonding performance and overall stability of the sliding layer 102. At the same time, the cement mortar or fine aggregate concrete can seal the pores of the surrounding rock, reduce initial seepage, and prevent groundwater or other impurities from having an adverse effect on the subsequent structural layers, providing a good foundation for the entire gas storage sealing structure.

[0056] In the specific implementation process, the leveling layer 101 is selected with different thicknesses and materials depending on the quality of the surrounding rock and the excavation deviation. Mortar or micro-expansion concrete can be used.

[0057] In this embodiment, the slip layer 102 serves to weaken the stress transmission of the surrounding rock and buffer stress concentration; as an intermediate mechanical transition layer between the rigid lining layer 103 and the flexible sealing layer 104, it is a necessary structure to prevent interface failure and local damage.

[0058] In the specific implementation process, the slip layer 102 can be applied in various ways, such as hot melt spraying or self-adhesive roll material, depending on the construction environment, so as to adapt to different cross sections or structures.

[0059] In a specific embodiment, the slip layer 102 is made of a sprayed material, and is configured as one of a modified bitumen-based elastomer, EPDM rubber composite roll, or self-adhesive polymer waterproofing pad. These materials all possess characteristics of low modulus, high elongation, and reliable shear resistance. The low modulus allows the slip layer 102 to deform more easily under stress, effectively buffering stress; the high elongation ensures that it will not easily break during surrounding rock deformation, continuously playing a role in dispersing stress transmission; the shear resistance ensures the structural integrity of the slip layer 102 under complex stress conditions, thereby comprehensively improving the performance of the slip layer 102 in the gas storage sealing structure. Furthermore, these materials can be applied using different construction techniques such as hot-melt spraying or wet-applied rolls, allowing for the selection of the most suitable method for slip layer 102 construction under different construction environments and cross-sectional conditions, greatly improving construction flexibility and adaptability, and contributing to improved project quality and efficiency.

[0060] In some embodiments, the thickness of the slip layer 102 is 5mm-20mm. Setting the thickness of the slip layer 102 to 5mm-20mm ensures that the slip layer 102 can effectively absorb the displacement disturbance induced by the surrounding rock cracks and disperse stress transmission, while also achieving a good balance between material usage and engineering costs. This avoids the slip layer 102 being too thin, which would prevent it from fully exerting its functions of dispersing stress and buffering deformation; it also avoids the slip layer 102 being too thick, which would increase material costs and affect the overall mechanical properties of the structure.

[0061] In a specific embodiment, the lining layer 103 is a concrete layer incorporating synthetic fibers, and the tensile strain of the lining layer 103 is ≥3%. By using a concrete layer incorporating synthetic fibers, the lining layer 103 becomes a high-ductility concrete. Under stress, it can form numerous fine cracks, unlike ordinary concrete which is prone to single large cracks. It effectively disperses stress, preventing structural integrity failure caused by a single large crack. When the internal pressure of the gas storage tank changes or is affected by surrounding rock deformation, the high-ductility concrete lining layer 103 can maintain the structural load-bearing capacity through its multi-crack characteristics, providing a stable support interface for the flexible sealing layer 104, while simultaneously improving the crack resistance and durability of the entire lining structure.

[0062] In specific embodiments, the synthetic fiber is polyvinyl alcohol (PVA) or polyethylene fiber. The selected synthetic fiber is PVA or PE fiber, which possesses high strength and high elastic modulus, and its incorporation into concrete can significantly improve the mechanical properties of the concrete. During concrete stress, the fiber bears part of the tensile stress through bridging, limiting the excessive opening of individual cracks and promoting stress transfer to adjacent areas, forming a controlled, dense, multi-crack distribution to enhance the ductility of the concrete.

[0063] In some embodiments, the thickness of the lining layer 103 is 100-250 mm. This thickness range design ensures that the lining layer 103 has sufficient load-bearing capacity without causing material waste or affecting other structural properties due to excessive thickness. This ensures that the lining layer 103 can stably perform its function of bearing pressure and dispersing stress under different working conditions.

[0064] In this embodiment, the lining layer 103 serves as the main bearing structure and is made of high-ductility concrete (ECC). After being subjected to stress, it forms numerous fine cracks, effectively avoiding structural integrity issues caused by a single large crack. This is the core component that ensures the overall bearing capacity and the stability of the flexible sealing support.

[0065] In the specific implementation process, the lining layer 103 should be constructed by continuous spraying, and efficiency can be improved by using multiple spray nozzles or automated robotic arms to ensure the integrity of the structure and the quality of the molding.

[0066] In a specific embodiment, the flexible sealing layer 104 is a polyurea, polyurethane, or butyl rubber coating with a thickness of 1-5 mm. The temperature resistance range of the flexible sealing layer 104 is -40℃ to 100℃. This type of material possesses excellent adhesion, anti-aging properties, and airtightness. High adhesion ensures a tight bond between the sealing layer and the lining layer 103, preventing detachment. Anti-aging properties ensure stable performance of the sealing layer during long-term use. The wide temperature resistance range of -40℃ to 100℃ adapts to temperature changes during gas storage operation, meeting gas storage requirements. Excellent airtightness is crucial for ensuring the sealing effect of the gas storage facility, effectively preventing compressed air leakage and ensuring efficient and stable operation.

[0067] In this embodiment, the flexible sealing layer 104 is sprayed on the inner wall surface of the lining layer 103 to construct an airtight closed interface. The material must have excellent adhesion and ductility and can deform in coordination with the lining layer 103 to maintain sealing performance for a long time.

[0068] In some embodiments, the leveling layer 101, sliding layer 102, lining layer 103, and flexible sealing layer 104 are sealed and abutted against each other, and are nested together to form a continuous closed annular structure. This design effectively avoids the generation of gas leakage paths and greatly improves the airtightness of the gas storage facility. At the same time, the continuous closed annular structure enhances the cooperative working ability between the layers, enabling the entire sealing structure to withstand external forces such as pressure, temperature changes, and surrounding rock deformation as a whole, improving the integrity and stability of the structure and ensuring the long-term safe operation of the gas storage facility.

[0069] In the specific implementation process, the outer side of the sealing structure is equipped with circumferential drainage blind pipes and longitudinal drainage blind pipes to collect and drain water during the construction and energy storage operation stages, so as to avoid external water pressure affecting the stability of the flexible sealing layer 104.

[0070] This invention proposes incorporating a slip layer 102 into the lining structure of an artificial underground gas storage facility to alleviate localized stress concentration caused by high-pressure cracking of the surrounding rock. See also... Figure 4 The mechanism of action can be explained using the flexible shear layer model in contact mechanics. Under high internal pressure operating conditions, cracking of the surrounding rock is inevitable, mainly manifested as opening along the circumferential direction of the gas storage tank. If the surrounding rock and the lining layer 103 are rigidly connected, this type of deformation will be directly transmitted to the concrete lining structure in the form of steep gradient shear stress, causing stress concentration, resulting in cracking of the lining layer 103, and subsequently structural damage such as puncture of the sealing layer. The slip layer 102 introduced in this invention can be equivalent to a flexible shear buffer layer, and its shear stress transmission mode can be described by the following model:

[0071]

[0072] Where τ(x) is the shear stress in slip layer 102; G is the shear modulus of slip layer 102; du(x) / dx is the displacement gradient of slip layer 102 along the x direction; and t is the thickness of slip layer 102.

[0073] According to the model, the magnitude of the shear stress in the slip layer 102 is proportional to the material stiffness G, thickness t, and displacement gradient. When a low-modulus material (such as rubber, modified asphalt, etc.) is selected and the thickness is reasonably set, the peak shear stress can be significantly reduced, achieving stress diffusion transmission. That is, the stress disturbance originally concentrated at a certain point is transformed into a stress distribution over a wider area along the x-direction, thereby weakening the destructive effect of local stress concentration on the lining layer 103 and the flexible sealing layer 104.

[0074] The presence of the slip layer 102 allows the surrounding rock to undergo a certain degree of circumferential relative movement without directly affecting the inner structure, effectively establishing a multi-layered structural system of rigid surrounding rock, flexible buffer, ductile pressure bearing and flexible sealing; this structural system improves the deformation coordination and operational stability of the structure, and is the key technical basis for the present invention to resist the failure of the sealing system induced by the cracking of the surrounding rock.

[0075] This scheme can provide a theoretical basis for the design and material selection of the slip layer 102. Designers can select materials with low shear modulus G, reasonably set the thickness t, and combine the displacement gradient du(x) / dx under actual working conditions to accurately control the magnitude of shear stress in the slip layer 102, ensuring that it works effectively within the design range, better play the role of dispersing stress transfer and protecting the inner structure, and also facilitate mechanical analysis and optimization of the structure.

[0076] According to an embodiment of the present invention, another aspect provides a construction method for a template-free, continuously formed sealing structure of an artificial underground gas storage facility for compressed air energy storage, see [link to relevant documentation]. Figure 2and Figure 3 , Figure 2 This is a construction schematic diagram of a template-free, continuously formed sealed artificial underground gas storage structure for compressed air energy storage. Figure 3 This is a construction flowchart for a template-free, continuously formed sealed artificial underground gas storage facility for compressed air energy storage; the construction method includes the following steps:

[0077] S1. Spray cement mortar or fine aggregate concrete onto the excavation surface of the surrounding rock to form a leveling layer 101 with a thickness of 20mm-100mm, and smooth the surface.

[0078] S2. A sliding layer 102 with a thickness of 5mm-20mm is laid on the inner surface of the leveling layer 101 by hot melt spraying or wet roll bonding process.

[0079] S3. Continuously spray concrete on the inner surface of the slip layer 102 to form a lining layer 103 with a thickness of 100mm-250mm;

[0080] S4. After the lining layer 103 has been cured to the required standard, a flexible sealing material is sprayed onto its inner surface to form a flexible sealing layer 104 with a thickness of 1-5mm.

[0081] This construction method first sprays cement mortar or fine aggregate concrete onto the excavated rock face to form a leveling layer 101. Then, a sliding layer 102 is laid on the inner surface of the leveling layer 101. Next, concrete is sprayed onto the inner surface of the sliding layer 102 to form a lining layer 103. Finally, after the lining layer 103 has cured to the required standard, a flexible sealing layer 104 is sprayed on. The entire construction process adopts a continuous advancement method, with each step closely connected. This eliminates the traditional formwork and jointing techniques, greatly simplifying the construction process, shortening the construction cycle, reducing sealing risks caused by construction joints, and improving construction efficiency and structural integrity. This construction method ensures the performance of the entire gas storage facility's sealing structure, giving it excellent performance in terms of sealing, stability, and durability.

[0082] The specific implementation steps of this construction method are as follows:

[0083] (1) Construction of Leveling Layer 101: After blasting or mechanical excavation, the surrounding rock of the gas storage facility exhibits significant geometric deviations on its surface, making it unsuitable as the construction base for the sliding layer 102 or lining layer 103. To form a uniform and dense stress interface, a leveling layer 101 with a thickness of less than 100mm (depending on the excavation flatness) is first laid using a spraying method. A 1:2 cement mortar or concrete can be used. After completion, the leveling layer 101 is smoothed. The leveling layer 101 not only corrects excavation errors but also seals the surrounding rock pores and controls initial seepage, contributing to the bonding stability of the subsequent sliding layer 102.

[0084] (2) Construction of Slip Layer 102: After the leveling layer 101 is cured, the slip layer 102 is sprayed on its inner side, with a thickness of approximately 20mm or less. This layer is the core component of this invention and must possess low modulus, high elongation, and shear strength. Commonly used materials include modified bitumen-based elastomers, EPDM rubber composite membranes, and self-adhesive polymer waterproofing mats. The construction method can be hot-melt spraying or wet-laying of membranes, depending on the material form. If spraying is used, smoothing is required after spraying. The slip layer 102 allows for limited sliding under shear stress during the service life of the structure, which can significantly alleviate the local stress peaks transmitted inward from the cracking of the surrounding rock.

[0085] (3) Construction of High-Ductility Concrete Lining Layer 103: After the slip layer 102 is constructed, a high-ductility concrete (ECC) layer with a thickness of 100-250mm is sprayed onto its inner surface and smoothed. Lining layer 103 is fine aggregate concrete mixed with PVA or PE fibers, with a tensile strain ≥3%, and it has the characteristic of multi-crack micro-propagation. Lining layer 103 is constructed by continuously spraying a robotic arm along the longitudinal direction of the tunnel without setting up formwork, forming a closed pressure-bearing structure ring by ring. Its high ductility can disperse and release micro-cracks, maintain the overall integrity of the lining, and provide a stable support interface.

[0086] (4) Construction of Flexible Sealing Layer 104: After the lining layer 103 has been cured for 28 days or treated with an early-strength agent to reach its design strength, a flexible sealing material with a thickness of less than 5 mm is sprayed onto its inner surface. Materials with high adhesion, anti-aging properties, wide temperature range (-40℃~+100℃), and excellent airtightness can be selected, such as polyurea, polyurethane, or butyl rubber modified coatings. The sealing layer construction adopts multi-head synchronous spraying operation to ensure uniform and defect-free film formation.

[0087] (5) Structural acceptance and sealing test: After the entire cross-section composite lining is completed, a sealing test (such as 10MPa pressure increase and pressure holding for 72h), interface cavity ultrasonic testing, and lining layer 103 crack monitoring should be carried out to ensure that the slip layer 102 is not damaged and the sealing layer does not show early signs of damage such as bulging or voiding. Only then can the gas storage operation stage be entered.

[0088] This construction method employs a continuous advancement approach, sequentially completing four layers from the excavation face: leveling, sliding, lining, and sealing. Each layer is constructed closely following the previous one, achieving a seamless, formwork-free, and joint-free integral structure, significantly improving construction efficiency and sealing reliability. The sliding layer 102 is a key structure of this invention; its flexible, low-modulus characteristics effectively weaken the stress transmission from surrounding rock deformation and cracks to the inner layer, reducing local stress concentration in the sealing layer. The lining layer 103 possesses good ductility and multi-crack control capabilities, and can work with the sliding layer 102 to disperse circumferential stress, preventing brittle failure of the lining. The sealing layer is easy to construct and can be tightly bonded to the lining layer 103 through a spraying process, forming a highly reliable airtight sealing surface that adapts to pressure fluctuations and long-term operating conditions.

[0089] The core of this invention lies in constructing a multi-layered synergistic system of sliding buffer, ductile pressure bearing, and flexible sealing in an artificial underground compressed air storage structure, forming an effective stress buffer path. By setting a sliding layer 102 with low modulus characteristics, stress concentration caused by surrounding rock deformation is weakened through shear release. Combined with a high-ductility concrete lining layer 103, the structure achieves flexible pressure bearing and crack dispersion, providing a uniform support surface. A highly adhesive sprayed sealing layer is arranged on the innermost side to ensure airtightness. The flexible sealing layer 104 deforms in coordination with the lining on the basis of good adhesion. The whole structure adopts a template-free continuous spraying construction method to form a seamless lining system, which comprehensively solves the problems of easy cracking, sealing failure, and many construction joints in traditional structures, significantly improving the reliability, adaptability, and construction efficiency of the structure.

[0090] This invention employs a continuous spraying process to replace traditional formwork casting, achieving seamless, integrated structural molding. This process simplifies the construction process, shortens the cycle, avoids sealing risks associated with structural joints, and possesses excellent adaptability, allowing for flexible selection of different equipment and material combinations based on cross-sectional dimensions and construction conditions, significantly improving construction efficiency and molding quality.

[0091] The structural design provided by this invention focuses on durability and maintainability. The sealing layer can be repaired locally by spraying without damaging the lining, reducing maintenance costs and downtime risks. The overall structure has good theoretical support and stress analysis basis, which facilitates subsequent health monitoring and design optimization, and improves the reliability and controllability of the system in long-term operation.

[0092] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A template-free, continuously formed sealing structure for an artificial underground gas storage facility for compressed air energy storage, characterized in that, It includes a leveling layer (101), a sliding layer (102), a lining layer (103), and a flexible sealing layer (104) arranged sequentially from the outside to the inside; The leveling layer (101) is suitable for covering the excavation face of the surrounding rock; The sliding layer (102) is disposed on the inner wall surface of the leveling layer (101); The lining layer (103) is disposed on the inner wall surface of the sliding layer (102); The flexible sealing layer (104) is sealed on the inner wall surface of the lining layer (103); The slip layer (102) is configured to absorb displacement disturbances induced by surrounding rock cracks through its own shear deformation, thereby dispersing stress transmission to the lining layer (103).

2. The template-free, continuously formed sealed structure for compressed air energy storage in an artificial underground gas storage facility according to claim 1, characterized in that, The slip layer (102) is made of sprayed material and is configured as one of modified bitumen-based elastomer, EPDM rubber composite roll or self-adhesive polymer waterproof pad.

3. The template-free, continuously formed sealed structure for compressed air energy storage in an artificial underground gas storage facility according to claim 2, characterized in that, The thickness of the slip layer (102) is 5mm-20mm.

4. The template-free, continuously formed sealed structure for compressed air energy storage in an artificial underground gas storage facility according to claim 1, characterized in that, The shear stress of the slip layer (102) satisfies the following model: Where τ(x) is the shear stress in the slip layer (102); G is the shear modulus of the slip layer (102) material; du(x) / dx is the displacement gradient of the slip layer (102) along the x direction; and t is the thickness of the slip layer (102).

5. The template-free, continuously formed sealed structure for compressed air energy storage in an artificial underground gas storage facility according to claim 1, characterized in that, The leveling layer (101) is set as a cement mortar or fine aggregate concrete layer with a thickness of 20mm-100mm; the leveling layer (101) is sprayed and formed to cover the excavated surface of the surrounding rock to repair the base surface and seal the pores of the surrounding rock.

6. The template-free, continuously formed sealed structure for compressed air energy storage in an artificial underground gas storage facility according to claim 1, characterized in that, The lining layer (103) is a concrete layer mixed with synthetic fibers, and the tensile strain of the lining layer (103) is ≥3%.

7. The template-free, continuously formed sealed structure for compressed air energy storage in an artificial underground gas storage facility according to claim 6, characterized in that, The synthetic fiber is polyvinyl alcohol or polyethylene fiber; and / or; The thickness of the lining layer (103) is 100-250 mm.

8. The template-free, continuously formed sealed structure for compressed air energy storage in an artificial underground gas storage facility according to claim 1, characterized in that, The flexible sealing layer (104) is a polyurea, polyurethane or butyl rubber coating with a thickness of 1-5 mm, and the temperature resistance range of the flexible sealing layer (104) is -40℃ to 100℃.

9. The template-free, continuously formed sealed structure for compressed air energy storage artificial underground gas storage according to any one of claims 1-8, characterized in that, The leveling layer (101), sliding layer (102), lining layer (103) and flexible sealing layer (104) are sealed and abutted against each other, and are nested together to form a continuous closed ring structure.

10. A construction method for a template-free, continuously formed sealed structure of an artificial underground gas storage facility for compressed air energy storage, characterized in that, Includes the following steps: S1. Spray cement mortar or fine aggregate concrete onto the excavation surface of the surrounding rock to form a leveling layer (101) with a thickness of 20mm-100mm, and smooth the surface. S2. A sliding layer (102) with a thickness of 5mm-20mm is laid on the inner surface of the leveling layer (101) by hot melt spraying or wet roll application. S3. Continuously spray concrete on the inner surface of the slip layer (102) to form a lining layer (103) with a thickness of 100mm-250mm; S4. After the lining layer (103) has been cured to the required standard, a flexible sealing material is sprayed on its inner surface to form a flexible sealing layer (104) with a thickness of 1-5mm.

Images