Multi-layer flexible sealing structure of underground artificial gas storage and implementation method

Abstract

The invention provides a multi-layer flexible sealing structure of an underground artificial gas storage and an implementation method. The multi-layer sealing structure comprises a rock surrounding layer, a concrete lining layer, a steel plate layer and a flexible sealing layer which are sequentially arranged from outside to inside. Through step-by-step cooperative protection of surrounding rock pressure bearing, concrete lining pressure transmission, steel plate lining crack crossing and flexible sealing layer sealing, the sealing performance of the gas storage under the operation conditions of high air pressure, large temperature difference, frequent inflation and deflation and the like is met, the construction efficiency and economical efficiency are guaranteed, sealing and reliable operation of the gas storage are achieved, and the sealing performance of the gas storage is improved. Installation and construction processes are efficient and fast.

Description

Technical Field

[0001] This invention relates to the field of compressed air energy storage technology, specifically to a multi-layer flexible sealing structure and implementation method for an underground artificial gas storage facility. Background Technology

[0002] The basic principle of compressed air energy storage is to store energy and generate electricity by using compressed air as a conversion medium. During off-peak electricity demand periods, electrical energy is converted into the internal energy of compressed air and stored in underground caverns. During peak electricity demand periods, the internal energy of compressed air is converted into mechanical energy to drive generator sets to output electrical energy, thereby achieving power generation.

[0003] Compressed air energy storage power stations mainly employ two types of gas storage facilities: above-ground and underground. Considering both safety and economy, underground gas storage is the preferred choice. Artificially excavated underground gas storage caverns, as a type of underground gas storage facility, offer advantages such as flexible site selection, controllable construction costs, and outstanding safety performance, making them an important technical route for underground gas storage facilities with promising prospects for widespread application.

[0004] To date, there are no successful examples of underground artificial caverns for compressed air energy storage worldwide. With the continuous increase in installed capacity of compressed air energy storage power plants and the ever-increasing demands for operational efficiency, artificial cavern gas storage facilities face a series of extreme technical challenges during design and construction. These challenges include high-pressure bearing capacity, with internal pressures reaching up to 18 MPa, and excellent sealing performance to prevent gas leakage. Furthermore, the gas storage facilities must possess long-term cyclic pressure bearing capacity, typically withstanding over 10,000 high-pressure cycles, and maintaining structural stability in high-temperature environments, such as long-term tolerance to temperatures up to 150°C. These stringent requirements aim to ensure the gas storage facilities maintain structural stability and high operational reliability throughout their entire service life.

[0005] Currently, the sealing technology for underground gas storage facilities largely references the pressure-bearing sealing technology of steel-lined tunnels widely used in hydraulic engineering. The core design principle of this approach is to allow the steel lining and the surrounding rock to share the internal pressure, with each bearing a certain load, the steel lining primarily functioning as a load-bearing component. Given the extremely high internal pressure of the gas storage facility, such as under a working pressure of 20 MPa, the required steel lining thickness typically needs to be 20 mm or more. To meet this high strength requirement, high-strength steel with a tensile strength of 800 MPa is necessary. Furthermore, the welding of the steel lining is extremely complex and labor-intensive, demanding very high standards in construction techniques and quality control, resulting in significant technical challenges and high overall costs.

[0006] Therefore, scientifically designing the sealing structure of underground gas storage facilities to achieve stable and reliable sealing while taking into account construction convenience and economic rationality is of great significance for ensuring the safe and stable operation of gas storage facilities. Summary of the Invention

[0007] To overcome the shortcomings of the above-mentioned technologies, the purpose of this invention is to provide a multi-layered flexible sealing structure and implementation method for underground artificial gas storage, which solves the problems that existing underground gas storage sealing structures cannot cope with complex operating conditions such as high pressure, large temperature difference, and frequent gas filling and releasing, and the high technical difficulty. It has the advantages of good stability and sealing reliability, and efficient and quick installation and construction process.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A multi-layer flexible sealing structure for an underground artificial gas storage facility is characterized by comprising, from the outside to the inside, a surrounding rock layer, a concrete lining layer, a steel plate layer, and a flexible sealing layer.

[0009] Furthermore, the concrete lining layer is tightly bonded to the inner surface of the surrounding rock layer, which is used to uniformly transfer the gas pressure inside the gas storage tank to the surrounding rock, and at the same time provide a flat base surface for the laying of the steel plate layer; the thickness of the concrete lining layer is 250~600mm, and it uses self-compacting concrete material with a strength grade of C30~C60.

[0010] Furthermore, the steel plate layer is tightly bonded to the inner surface of the concrete lining layer to bridge cracks generated under high pressure in the concrete lining layer, thereby preventing large local deformations and ensuring the integrity and airtightness of the sealing layer; the thickness of the steel plate layer is 1~8mm, and it is made of carbon steel; the steel plate layer is formed by splicing multiple steel plates and covers the inner surface of the concrete lining layer.

[0011] Furthermore, the steel plate layer and the concrete lining layer are fixedly connected by epoxy adhesive and bolts, thereby improving structural stability.

[0012] Furthermore, a steel strip is fixedly installed at the joint between adjacent steel plates, and the steel strip covers the joint to reinforce the joint.

[0013] Furthermore, the steel strips are fixedly connected to the steel plate by bolts.

[0014] Furthermore, the flexible sealing layer is uniformly sprayed onto the inner surface of the steel plate layer and is tightly adhered to the steel plate layer; the thickness of the flexible sealing layer is 5~15mm, and it is made of special polyurea material; the flexible sealing layer is tightly adhered to the steel plate layer, has good sealing performance, strong deformation adaptability, and excellent physical and chemical properties, and mainly plays a sealing role.

[0015] This invention also provides a method for implementing the multi-layer flexible sealing structure of the above-mentioned underground artificial gas storage facility, applicable to the flexible sealing cave wall structure of underground artificial gas storage facilities, comprising the following steps: 1) Geological survey and site selection, and preliminary excavation of the underground artificial gas storage space within the surrounding rock, and application of support measures to the excavated surrounding rock to obtain the surrounding rock layer; 2) After excavation, a concrete lining layer is constructed on the surface of the surrounding rock; 3) Grind and clean the surface dust of the concrete lining layer, and then install the steel plate layer using the pasting and splicing process, and use bolts to fix the steel plate to the concrete lining layer tightly. 4) A flexible sealing layer is applied to the surface of the steel plate layer to form the entire multi-layer flexible sealing structure.

[0016] As a preferred embodiment, step 3) includes the following steps in the installation process of the steel plate layer: The steel plates are cut, rolled, and cleaned, and holes are pre-drilled in the steel plates for subsequent splicing. The position of each steel plate is determined by positioning it on the surface of the concrete lining layer using a laser level. Then, the steel plates are bonded and fixed to the concrete lining layer using epoxy adhesive. After bonding, each steel plate is further fixed to the concrete lining layer using bolts. After all the steel plates are laid, the steel strips are fixed at the joints of the steel plates and the joints are reinforced to ensure that the steel plate layer completely covers the surface of the concrete lining layer.

[0017] Furthermore, the steel strip is fixedly connected to the steel plate by bolts; the steel strip is pre-drilled, and then the pre-drilled steel strip is fixed to the joint of the steel plate by bolts.

[0018] As a preferred embodiment, in step 4), the flexible sealing layer is a polyurea layer, which is sprayed using automated equipment and sprayed multiple times evenly until the thickness is 5-15mm to form a flexible sealing layer.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention proposes a multi-layered flexible sealing structure and implementation method for underground artificial gas storage facilities. It utilizes a concrete lining layer to transfer pressure to the surrounding rock, a steel plate layer to bridge lining cracks, and a flexible polyurea layer to seal the gas storage facility under high-pressure conditions. By leveraging the superior properties of each layer's materials, coordinating their effects, providing layer-by-layer protection, and achieving multi-layered sealing, this invention ensures the stability and airtightness of the gas storage facility, enabling safe operation and efficient, rapid installation and construction. Attached Figure Description

[0020] Figure 1This is a schematic diagram of a multi-layer flexible sealing structure for an underground artificial gas storage facility according to the present invention; Figure 2 This is a schematic diagram of the steel plate layer installation of the multi-layer flexible sealing structure of the present invention; Figure 3 This is a flowchart illustrating the implementation method of a multi-layer flexible sealing structure for an underground artificial gas storage facility according to the present invention. The components are: 1. Surrounding rock layer; 2. Concrete lining layer; 3. Steel plate layer; 4. Epoxy adhesive; 5. Flexible sealing layer; 6. Bolts; 7. Gaskets; 8. Steel strips. Detailed Implementation

[0021] 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 a part of the embodiments of the present invention, and not all of them. 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.

[0022] Example 1 like Figure 1 As shown, a multi-layered flexible sealed cavern wall structure for an underground artificial gas storage facility includes, from the outside in, a surrounding rock layer 1, a concrete lining layer 2, a steel plate layer 3, and a flexible sealing layer 5. The cross-sectional structure of this multi-layered flexible sealing structure is circular, with smooth transitions at the joints of each side to avoid sharp corners. This composite flexible sealing structure allows for cracking of the concrete lining layer 2 to a certain extent. The high strength of the steel plate layer 3 enables it to bridge concrete cracks, and the flexible sealing layer 5, with its adaptability to deformation and strong sealing properties, ensures the sealing and stability of the gas storage facility during operation.

[0023] The surrounding rock layer 1 is used to bear the high internal pressure load during the operation of the gas storage facility. It is obtained by excavating underground caverns by utilizing the high bearing capacity of the surrounding rock.

[0024] The inner surface of the concrete lining layer 2 is smooth; the concrete lining layer 2 is tightly bonded to the inner surface of the surrounding rock layer 1, serving to smooth the wall surface after the gas storage tank is excavated, ensuring that the internal gas pressure of the gas storage tank can be evenly transmitted to the surrounding rock, and providing a smooth base surface for the laying of the steel plate layer 3; the thickness of the concrete lining layer 2 is 250~600mm, and it uses self-compacting concrete material with a strength grade of C30~C60. The concrete lining layer 2 can evenly transmit the internal gas pressure of the gas storage tank to the surrounding rock layer 1 and provide a smooth base surface for the laying of the steel plate layer 3.

[0025] like Figure 1 and Figure 2As shown, the steel plate layer 3 covers the inner surface of the concrete lining layer 2. Its main function is to bridge cracks generated under high pressure in the lining, prevent large local deformations, and ensure the integrity and airtightness of the sealing layer. The steel plate layer 3 is tightly bonded to the concrete lining layer 2 using epoxy adhesive 4, and the steel plate layer 3 is also fixedly connected to the concrete lining layer 2 by bolts 6. The epoxy adhesive 4 and bolts 6 together fix the steel plate layer 3 to the concrete lining layer 2. The thickness of the steel plate layer 3 is 1~8mm, and it is made of carbon steel, which has high strength and good ductility. Figure 2 As shown, steel plate layer 3 is formed by splicing multiple steel plates, avoiding welding operations and improving efficiency. Steel strips 8 are fixed to the joints between adjacent steel plates using bolts 6. These steel strips 8 cover the joints of adjacent steel plates on the inner side of steel plate layer 3, providing coverage and sealing. Bolts 6 are fitted with washers 7, which have an inner diameter of 6mm and a thickness of 2mm.

[0026] The flexible sealing layer 5 is formed by multiple uniform sprayings onto the inner surface of the steel plate layer 3, primarily serving a sealing function and adhering tightly to the steel plate layer 3. The flexible sealing layer 5 has a thickness of 5-15mm and is made of a special polyurea material. The high strength and deformation adaptability of polyurea allow it to withstand radial displacement and circumferential strain in the tunnel chamber under high pressure conditions. The air permeability resistance and seamless spraying characteristics of polyurea enable it to form a complete barrier, preventing air molecules from leaking to the outside of the gas storage facility. Furthermore, the polyurea construction process is highly adaptable to the environment, maintaining good construction quality under a wide range of temperature and humidity conditions, thus ensuring stable sealing performance in various complex environments.

[0027] Example 2 like Figure 3 As shown, a method for implementing a multi-layer flexible sealing structure for an underground artificial gas storage facility, applicable to the multi-layer flexible sealing structure of the underground artificial gas storage facility in Example 1, includes the following steps: 1) First, conduct geological surveys and select underground rock strata with good surrounding rock conditions, no large number of faults, high strength, and generally Class III or above as the excavation site for the underground gas storage. In the surrounding rock, the gas storage space of the underground gas storage is initially excavated. After excavation, grouting reinforcement, plain shotcrete and other support measures are applied to the surrounding rock to improve the overall stability of the gas storage and obtain the surrounding rock strata.

[0028] 2) After excavation, a concrete lining layer with a thickness of 250-600mm and a concrete strength grade range of C30-C60 is constructed on the surface of the surrounding rock. During the construction of the concrete lining layer, backfilling and grouting processes are required to ensure a tight bond between the concrete lining layer and the surrounding rock, avoiding cavities, and providing a flat foundation surface for the construction of the steel plate layer.

[0029] 3) During the construction of the steel plate layer, the surface of the concrete lining layer needs to be ground and cleaned of surface dust to ensure a smooth surface. The steel plate thickness is 1-8mm. Then, the steel plate layer is installed using a splicing and bonding process, fixing the steel plate with bolts and epoxy adhesive to ensure a tight bond between the steel plate and the concrete lining layer. The installation of the steel plate layer using a splicing and bonding process includes the following steps: The steel plates are cut, rolled, and cleaned, and holes are pre-drilled in the steel plates to facilitate subsequent splicing. The position of each steel plate is determined by positioning it on the surface of the concrete lining layer using a laser level. Then, the steel plates are bonded and fixed to the concrete lining layer using epoxy adhesive. After bonding, each steel plate is further fixed to the concrete lining layer using bolts. After all the steel plates are laid, the pre-drilled steel strips are fixed to the joints of the steel plates with bolts to reinforce the joints.

[0030] 4) An automated spraying process is used to apply a flexible sealing layer to the surface of the steel plate. The flexible sealing layer is a special polyurea layer. After the steel plate is ground, rusted, cleaned, and primed, the polyurea layer is applied to the steel plate. Automated equipment is used for spraying. Multiple even sprayings are required to achieve a thickness of 5-15mm to achieve a complete sealing layer.

[0031] This invention proposes a multi-layer flexible sealing structure and implementation method for underground gas storage. The structure provides step-by-step coordinated protection through surrounding rock bearing, concrete lining pressure transmission, steel plates crossing lining cracks, and flexible sealing layer sealing. This ensures the sealing performance of the gas storage under operating conditions such as high pressure, large temperature difference, and frequent gas filling and releasing, guarantees construction efficiency and economy, and achieves the sealing and reliable operation of the gas storage.

[0032] This invention utilizes steel plates to bridge cracks in concrete lining under high pressure, improving the reliability of the sealing structure. The joints between the steel plates are covered with steel strips, enhancing the overall stability of the structure. Furthermore, the steel plates are installed using adhesive and bolt fixing techniques, eliminating the need for welding, thus simplifying construction and ensuring both progress and cost-effectiveness.

[0033] This invention utilizes the sealing and deformation adaptability of a special polyurea to achieve sealing and stability under high internal pressure. The steel plate provides protection for the polyurea layer across lining cracks, preventing tearing and jointly ensuring the sealing performance and reliability of the structure. An automated spraying process achieves seamless application, offering strong adaptability and ensuring the integrity of the sealing structure.

[0034] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the inventive concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A multi-layer flexible sealing structure for an underground artificial gas storage facility, characterized in that, It includes, from the outside to the inside, a surrounding rock layer, a concrete lining layer, a steel plate layer, and a flexible sealing layer.

2. The multi-layer flexible sealing structure according to claim 1, characterized in that, The concrete lining layer is tightly bonded to the inner surface of the surrounding rock layer; the concrete lining layer is made of self-compacting concrete material with a strength grade of C30~C60.

3. The multi-layer flexible sealing structure according to claim 1, characterized in that, The steel plate layer is tightly bonded to the inner side of the concrete lining layer; the steel plate layer has a thickness of 1~8mm and is made of carbon steel. The steel plate layer is formed by splicing together multiple steel plates and covers the inner surface of the concrete lining layer.

4. The multi-layer flexible sealing structure according to claim 3, characterized in that, The steel plate layer and the concrete lining layer are fixedly connected by epoxy adhesive and bolts.

5. The multi-layer flexible sealing structure according to claim 3, characterized in that, A steel strip is fixedly installed at the joint between adjacent steel plates, and the steel strip covers the joint.

6. The multi-layer flexible sealing structure according to claim 5, characterized in that, The steel strips are fixedly connected to the steel plate by bolts.

7. The multi-layer flexible sealing structure according to claim 1, characterized in that, The flexible sealing layer is uniformly sprayed onto the inner side of the steel plate layer and is tightly adhered to the steel plate layer; the flexible sealing layer is made of special polyurea material.

8. A method for implementing the multi-layer flexible sealing structure of the underground artificial gas storage facility according to any one of claims 1 to 7, characterized in that, Includes the following steps: 1) Geological survey and site selection, and excavation of underground artificial gas storage space within the surrounding rock to obtain the surrounding rock layer; 2) After excavation, a concrete lining layer is constructed on the surface of the surrounding rock; 3) Grind the surface of the concrete lining layer, and then install the steel plate layer on the surface of the concrete lining layer using the bonding and splicing process. Use bolts to fix the steel plate and tightly bond it to the concrete lining layer. 4) A flexible sealing layer is applied to the surface of the steel plate layer to form the entire multi-layer flexible sealing structure.

9. The implementation method according to claim 8, characterized in that, In step 3), the installation process of the steel plate layer includes the following steps: First, the steel plate is cut, rolled, and cleaned. At the same time, holes are pre-drilled in the steel plate to facilitate subsequent splicing. The position of each steel plate is determined on the surface of the concrete lining layer, and then the steel plates are bonded and fixed to the concrete lining layer with epoxy adhesive. After the bonding is completed, each steel plate is further fixed to the concrete lining layer with bolts. After all the steel plates are laid, the steel strips are fixed at the joints of the steel plates and the joints are reinforced to ensure that the steel plate layer completely covers the surface of the concrete lining layer.

10. The implementation method according to claim 9, characterized in that, The steel strips are fixedly connected to the steel plate by bolts; the steel strips are pre-drilled, and then the pre-drilled steel strips are fixed to the joint of the steel plate by bolts.

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