Prestressed tie-rod type compressed air reservoir structure

Abstract

The application discloses a prestressed pull rod type compressed air storage structure and belongs to the technical field of compressed air energy storage. The prestressed pull rod type compressed air storage structure comprises, from outside to inside, a shotcrete layer, a prestressed belt, a reinforced concrete lining layer, a buffer layer, a sealing layer, a ribbed beam and a plurality of hydraulic pull rods, and a pull ring structure. The ribbed beam is a steel structure ribbed beam and is arranged in sections in the axial direction of the chamber. The anchoring piece of the pull ring structure penetrates through the layers of structure to connect the prestressed belt, the reinforced concrete lining and the ribbed beam into a whole. The plurality of hydraulic pull rods are arranged along the circumferential direction and the axial direction of the storage structure and are connected with the pull ring. A pressure sensor is arranged in the air storage space. The pressure sensor and the hydraulic pull rods are connected to a controller. The controller is used for receiving the detection signal of the pressure sensor and adjusting the tension of each hydraulic pull rod, so that the lining layer is always in a compressed state. The bearing system of the prestressed pull rod type compressed air storage structure makes the lining layer always in a compressed state, effectively avoiding cracking and damage under the action of cyclic high pressure.

Description

Technical Field

[0001] This invention relates to the field of compressed air energy storage technology, specifically to a prestressed tie rod type compressed air storage structure. Background Technology

[0002] Compressed air energy storage (CAES), as a new type of large-scale energy storage, has broad application prospects in areas such as peak shaving and valley filling, renewable energy consumption, and grid frequency regulation due to its advantages such as large capacity, long lifespan, and fast response. Currently, underground compressed air storage facilities in artificial chambers mainly rely on abandoned coal mines or artificially excavated rock caves. The safety and airtightness of its core structure (the compressed air storage tank) directly determine the system's operating efficiency and lifespan.

[0003] Most existing underground gas storage facilities employ a combination of steel lining and concrete lining, with the lining bearing the high internal gas pressure and preventing gas leakage. However, during long-term operation, the repeated action of injection and production cycle pressures can easily lead to the expansion of micro-cracks between the lining and the surrounding rock, increasing the risk of leakage. Furthermore, traditional concrete lining structures, subjected to the combined effects of temperature gradients and gas pressure cycles, often experience cracking, spalling, or interface delamination, making it difficult to meet the requirements for long-term stable operation under high-pressure (>10MPa) and high-frequency cyclic conditions.

[0004] To strengthen storage tank structures, some studies have attempted to introduce measures such as steel mesh, steel lining plates, or high-performance concrete to improve overall pressure resistance. However, these methods often rely on improving the strength of the materials themselves, resulting in insufficient structural integrity and difficulty in effectively controlling the coupling effect between the lining and the surrounding rock. Under high stress environments, structural cracking and seepage channels are still difficult to avoid, and construction costs are high and maintenance is complex.

[0005] Therefore, how to further improve the integrity and stability of the storage structure, suppress the expansion of cracks under cyclic loads, and simplify the construction process while ensuring airtightness and pressure bearing capacity has become an urgent technical problem to be solved in current compressed air storage projects. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems in the prior art and provide a prestressed tie rod type compressed air storage structure.

[0007] This invention provides a prestressed tie-rod type compressed air storage structure, comprising, from the outside in: a shotcrete layer, a prestressed strip, a reinforced concrete lining layer, a buffer layer, a sealing layer, and ribs; and also includes multiple hydraulic tie rods and multiple pull ring structures. The shotcrete layer is formed by shotcreting concrete from the inner wall of the surrounding rock. The ribs are steel structure ribs, spaced at intervals along the axial direction of the chamber. The inner side of the sealing layer and the ribs forms an air storage space. The multiple pull ring structures are evenly distributed along the circumferential and axial directions of the chamber, and each pull ring structure includes an anchor and a pull ring at the end of the anchor. The anchor penetrates each layer, connecting the prestressed strip, the reinforced concrete lining, and the ribs into a whole. The pull rings are exposed in the air storage space. The multiple hydraulic tie rods are distributed along the circumferential and axial directions of the storage structure and connected to the prestressed strip via pull rings, used to apply prestress to the reinforced concrete lining layer. The air storage space is equipped with a pressure sensor for real-time monitoring of the air pressure inside the chamber. The pressure sensor and each hydraulic rod are connected to a controller. The controller receives the detection signal from the pressure sensor and adjusts the tension of each hydraulic rod according to the detection signal, so that the reinforced concrete lining layer is always under pressure.

[0008] Preferably, the reinforced concrete lining layer is assembled from multiple precast reinforced concrete segments, wherein the concrete in the precast reinforced concrete segments is ECC (engineering cement-based composite) concrete.

[0009] Preferably, the precast reinforced concrete segments have splicing joints at the joint locations, and grouting material is injected into the splicing joints.

[0010] Preferably, the buffer layer is a butyl rubber pad with a thickness of 5mm to 10mm.

[0011] Preferably, the sealing layer is a polymer coating with a thickness of 5mm to 10mm.

[0012] Preferably, the thickness of the reinforced concrete lining layer is 30cm to 40cm.

[0013] Preferably, the thickness of the sprayed concrete layer is 15cm to 25cm.

[0014] Preferably, polyurea-formaldehyde microcapsules are added to the polymer coating, and the polyurea-formaldehyde microcapsules encapsulate an epoxy resin repair agent.

[0015] Preferably, strain sensors are evenly distributed on the inner and outer sides of the reinforced concrete lining layer, and the strain sensors are signal-connected to the controller. The controller obtains the adjustment command of each hydraulic tie rod according to the air pressure in the air storage space, and calculates the bending strain based on the inner and outer strain sensors of each control section. Based on the comparison of the bending strain with a preset threshold, a local correction tension command for the hydraulic tie rod of that section is generated. The adjustment command and the local correction tension command are superimposed to generate the final tension command for each hydraulic tie rod. According to the final tension command, the tension of the corresponding hydraulic tie rod is adjusted so that the reinforced concrete lining layer is under a predominantly compressive stress state, both as a whole and locally.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: By introducing prestressed tie rods to constrain the shotcrete layer, reinforced concrete lining layer, buffer layer, sealing layer and rib beam, the present invention forms an integral pressure-bearing system of reinforced concrete lining layer, prestressed strip, rib beam and hydraulic tie rod, so that the reinforced concrete lining layer is always under pressure, effectively avoiding cracking and damage under cyclic high pressure, and significantly improving the safety and durability of the structure.

[0017] The buffer layer of this invention prevents the sealing layer from embedding into the gaps of the reinforced concrete lining layer and causing damage. Simultaneously, the sealing layer employs a self-healing polymer coating, significantly improving impermeability and sealing reliability. The reinforced concrete lining layer utilizes a precast segment structure made of high-ductility ECC material, combined with waterstops, rubber gaskets, and grouting to achieve multiple sealing barriers, further enhancing airtightness and overall integrity. The hydraulic tie rods and prestressed bands work synergistically to achieve real-time and flexible prestress adjustment, ensuring stable load-bearing capacity under different operating conditions. Compared to existing gas storage structures, this invention combines crack resistance, impermeability, ease of construction, and long-term service safety. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of an embodiment of the present invention.

[0019] Figure 2 This is a partially enlarged schematic diagram of the lining layer, buffer layer, and sealing layer in an embodiment of the present invention.

[0020] Explanation of reference numerals in the attached figures: 1. Surrounding rock; 2. Shotcrete layer; 3. Prestressed strip; 4. Reinforced concrete lining layer; 5. Buffer layer; 6. Sealing layer; 7. Rib beam; 8. Hydraulic tie rod; 2-1. Pore defects in reinforced concrete lining. Detailed Implementation

[0021] 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, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0022] Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, and do not exclude other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described objects changes, the relative positional relationship may also change accordingly.

[0023] The prestressed tie rod type compressed air storage structure of this embodiment includes, from the outside to the inside: a shotcrete layer 2, a prestressed band 3, a reinforced concrete lining layer 4, a buffer layer 5, a sealing layer 6, and a rib beam 7. It also includes multiple hydraulic tie rods 8 and multiple pull ring structures. The shotcrete layer 2 is formed by shotcreting concrete from the inner wall of the surrounding rock 1. The rib beam 7 is a steel structure rib beam 7, which is set at intervals along the axial direction of the chamber. The inner side of the sealing layer 6 and the rib beam 7 is an air storage space. The multiple pull ring structures are evenly distributed along the circumferential and axial directions of the chamber. Each pull ring structure includes an anchor and a pull ring located at the end of the anchor. The anchor penetrates through each layer of the structure to connect the prestressed band 3, the reinforced concrete lining, and the rib beam 7 into a whole. The pull ring is exposed in the air storage space. The multiple hydraulic tie rods 8 are distributed along the circumferential and axial directions of the storage structure and are connected to the prestressed band 3 through the pull rings to apply prestress to the reinforced concrete lining layer 4. In this embodiment, the anchors of the pull ring structure penetrate through each layer of the structure, connecting the prestressed strip 3, the reinforced concrete lining, and the rib beam 7 into a whole. More specifically, as an example, the edge of the prestressed strip 3 is fixed with the pull ring by welding or mechanical embedding. Fixing holes that mate with the anchors are provided on the steel rib beam 7, corresponding to the fixing pull rings of the prestressed strip 3. During construction, the anchors of the pull ring structure are inserted through the fixing holes and connected to the fixing pull rings on the prestressed strip 3 via steel strands. The anchors are fixed to the prestressed strip 3, the reinforced concrete lining, and the rib beam 7 by welding or limiting the position of the anchors, thus forming a unified structure.

[0024] The air storage space is equipped with a pressure sensor for real-time monitoring of the air pressure inside the chamber. The pressure sensor and each hydraulic rod 8 are connected to a controller. The controller is used to receive the detection signal from the pressure sensor and adjust the tension of each hydraulic rod 8 according to the detection signal, so that the reinforced concrete lining layer 4 is always under pressure.

[0025] In this embodiment, the hydraulic linkage 8 of the entire storage tank can be divided into several control zones, and the hydraulic linkage 8 in each zone can be adjusted by an independent controller. Each rotation of the hydraulic linkage 8 can be considered as a zone, and each hydraulic linkage 8 has a built-in PLC controller that communicates with the zone's central controller. The overall control scheme is controlled by the zone's central controller.

[0026] In this embodiment, through the above-mentioned multi-layered structural arrangement, the storage tank can form an overall force-bearing system consisting of prestressed strip 3, reinforced concrete lining layer 4, rib beam 7 and hydraulic tie rod 8 while ensuring basic support and sealing performance, thereby effectively improving impermeability, durability and safety.

[0027] The construction method of the prestressed tie rod type compressed air storage structure in this embodiment is as follows: After the tunnel excavation is completed, the first layer of shotcrete is constructed. This layer is generally 15cm to 25cm thick and is mainly used to seal the cracks in the surrounding rock 1, suppress rockfall, and serve as the base for the subsequent lining layer construction.

[0028] A prestressed band 3 is installed inside the shotcrete layer 2. The prestressed band 3 is made of high-strength steel strip or steel strand to ensure high tensile strength and durability. The prestressed band 3 is arranged circumferentially along the gas storage tank, forming a continuous tension membrane. Surface prestressing is applied to ensure that the tension from the gas pressure is evenly distributed throughout the structure, enabling it to effectively withstand the tensile stress brought by the gas pressure. The prestressed band 3 applies tension uniformly, thus avoiding the localized stress concentration caused by traditional steel cables.

[0029] The thickness of the reinforced concrete lining layer 4 is 30cm to 40cm, and high-ductility ECC concrete is preferred to improve the crack resistance and impermeability of the structure. The reinforced concrete lining layer 4 adopts the precast segment assembly method: the precast segments are transported to the site and mechanically assembled to form a ring lining structure.

[0030] After the precast reinforced concrete lining segments are spliced, waterstops, rubber sealing gaskets, and epoxy grouting grooves are installed at the joints. Grouting material is injected into the joints after assembly to form a secondary sealing barrier, effectively ensuring the airtightness and integrity of the joints.

[0031] More specifically, the waterstop is installed at the joint of the precast reinforced concrete lining segments, that is, at the joint where two segments are joined. Rubber gaskets are usually placed on the outside or inside of the waterstop as an additional sealing measure, mainly serving to fill and compress during the splicing process, supplementing any tiny gaps that the waterstop cannot completely seal. Epoxy grouting grooves are placed inside the joint of the precast lining segments, located inside the waterstop and gaskets. The grouting grooves need to be pre-drilled before segment splicing, ensuring their shape and size match the flowability of the grouting material. During the splicing of precast lining segments, the waterstop is first installed in the pre-drilled groove at the joint of the precast lining segments. Next, the rubber gaskets are installed. Finally, epoxy grouting material is injected into the spliced ​​joint.

[0032] Steel structural ribs 7 are spaced apart inside the sealing layer 6. During construction, these ribs 7 are anchored to the prestressed bands 3 via tie rings, forming an integral load-bearing frame. Unlike conventional steel linings, the steel structural ribs 7 in this embodiment do not serve a sealing function; instead, by being spaced apart along the axial direction, they primarily enhance rigidity and distribute loads. Multiple tie ring structures are arranged along the outline of the storage structure on the inner side of the ribs 7 for connection to hydraulic tie rods 8. Specifically, the ends of these tie ring structures connect to the prestressed bands 3 between the reinforced concrete lining layers 4, and the stress of the prestressed bands 3 is adjusted by the tension applied by the hydraulic tie rods 8.

[0033] A buffer layer 5 with a thickness of 5mm to 10mm is provided between the reinforced concrete lining layer 4 and the sealing layer 6. Figure 2As shown, the buffer layer 5 is made of butyl rubber. Butyl rubber has unique advantages over other materials in terms of airtightness, elasticity, chemical resistance, aging resistance, and resistance to high and low temperatures. It is especially suitable for compressed air energy storage systems with high airtightness requirements and long-term operation. It can provide a certain deformation space under gas pressure, preventing the sealing layer 6 from being directly embedded in the pore defects 2-1 of the reinforced concrete lining and thus damaged, while absorbing some of the pressure impact. In this embodiment, the thickness of the buffer layer 5, 5mm to 10mm, can provide sufficient elasticity and cushioning effect without occupying too much space and affecting the gas storage capacity.

[0034] Strain sensors are arranged in pairs on the inner and outer sides of the reinforced concrete lining layer 4 to monitor the axial and bending strain of the reinforced concrete lining layer 4 in real time. The controller determines the bending direction of the reinforced concrete lining layer 4 based on the strain difference between the inner and outer sides, and then determines whether the section is under-compressed or over-compressed, which serves as the basis for local tensile force correction.

[0035] More specifically, pressure sensors are installed on the inner wall of the air storage space within the chamber to monitor the air storage pressure in real time. Strain sensors are arranged in pairs on the inner and outer sides of the key sections of the reinforced concrete lining layer 4 to monitor the lining strain in real time. The controller calculates the reference tension of all hydraulic tie rods 8 based on the chamber air pressure. For example, a corresponding functional relationship between tension and air pressure can be pre-fitted, and the controller can calculate the reference tension based on the air pressure to ensure that the reinforced concrete lining layer 4 is under compression as a whole. In each control section, the controller calculates the bending strain based on the strain values ​​on the inner and outer sides, determines whether it is under compression or tension, and locally adjusts the tie rod tension of that section according to the deviation to ensure that the reinforced concrete lining layer 4 is always under compression.

[0036] In this embodiment, the sealing layer 6 is arranged inside the buffer layer 5, and its thickness is generally 5mm to 10mm. The sealing layer 6 adopts a polymer coating, such as epoxy resin material, with polyurea-formaldehyde microcapsule carriers added inside. The microcapsules encapsulate epoxy resin repair agent. When the sealing layer 6 suffers microcracks or local damage, the repair agent can be automatically released, undergo a curing reaction, and fill the defects, thereby achieving a self-healing function and further improving the durability and service life of the sealing layer 6. In this embodiment, the 5mm to 10mm thickness of the sealing layer 6 provides sufficient airtightness without increasing the brittleness of the sealing material or the construction difficulty due to excessive thickness.

[0037] In this embodiment, the thickness of the reinforced concrete lining layer 4 is 30cm to 40cm. This thickness provides sufficient compressive strength while ensuring structural stability. Under high pressure, a thicker lining layer can effectively prevent cracking. If the storage requirements are high, an even thicker layer can be used.

[0038] In this embodiment, the thickness of the shotcrete layer 2 is 15cm to 25cm. The function of the shotcrete layer 2 is to stabilize the surrounding rock 1 and prevent problems such as rockfall and water seepage. A thickness of 15cm to 25cm provides good support capacity, but will not be too thick, causing the structure to be too heavy or increasing the construction difficulty. If the properties of the surrounding rock 1 are poor, the thickness needs to be increased.

[0039] Within the air storage space inside the sealing layer 6, multiple hydraulic tie rods 8 are arranged circumferentially and axially. These hydraulic tie rods 8 are connected to a ring structure inside the rib beam 7 and are subjected to prestress not less than the storage tank's ultimate operating air pressure during construction. This ensures the reinforced concrete lining layer 4 remains under compression, preventing tensile cracking or damage due to circulating air pressure. To avoid localized secondary bending moments or excessive compression during tie rod adjustment, the system employs a staged loading method. After each stage of prestressing, strain monitoring and air pressure feedback verification are performed. If excessive compression occurs in a span, the system automatically adjusts the tension in that span to prevent uneven stress distribution. By dynamically adjusting the prestressing of the hydraulic tie rods 8 through real-time monitoring of the chamber air pressure, this arrangement significantly improves the structural stability and safety of the storage tank during long-term operation.

[0040] Pressure sensors are primarily used to monitor changes in air pressure within the storage facility. During operation, the pressure sensors provide global data on air pressure fluctuations. The controller adjusts the prestress of the hydraulic tie rod 8 based on these pressure changes, ensuring that the reinforced concrete lining layer 4 remains under pressure throughout the entire process, preventing cracking or damage caused by drastic pressure fluctuations. The system employs a staged loading method. After each small stage of loading, strain monitoring and air pressure feedback verification automatically adjust the tension of the hydraulic tie rod 8, ensuring uniform global stress and thus improving the stability and safety of the gas storage facility during long-term operation.

[0041] Through the above embodiments, the prestressed tie-rod type compressed air storage structure of the present invention can effectively overcome the problems of cracking, leakage, and structural damage that are prone to occur in traditional gas storage caverns under high-pressure circulating operation conditions. In particular, during the prestressing adjustment process, the hydraulic tie-rod 8 system ensures that the lining in each area is always in a compressed state through real-time feedback adjustment, avoiding uneven stress and cracking caused by local pressure relief, thereby significantly improving the overall stability and safety of the gas storage. Its lining, prestressed band 3, rib beam 7, and hydraulic tie-rod 8 integrated pressure-bearing system achieves reasonable load distribution and constraint; the introduction of buffer layer 5 and self-healing sealing layer 6 significantly improves sealing performance and durability; and precast segments and secondary sealing measures ensure the structural construction quality and airtight integrity, thereby extending the service life of the storage while ensuring safety, and has broad engineering application prospects.

[0042] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A prestressed tie-rod type compressed air storage structure, characterized in that, From the outside in, the structure comprises: a shotcrete layer, a prestressed strip, a reinforced concrete lining layer, a buffer layer, a sealing layer, and ribs. It also includes multiple hydraulic tie rods and multiple pull ring structures. The shotcrete layer is formed by shotcreting concrete onto the inner wall of the surrounding rock. The ribs are steel structure ribs, spaced at intervals along the axial direction of the chamber. The inner side of the sealing layer and the ribs forms an air storage space. The multiple pull ring structures are evenly distributed along the circumferential and axial directions of the chamber, and each pull ring structure includes an anchor and a pull ring at the end of the anchor. The anchor penetrates each layer, connecting the prestressed strip, reinforced concrete lining, and ribs into a single unit. The pull rings are exposed in the air storage space. The multiple hydraulic tie rods are distributed along the circumferential and axial directions of the storage structure and connected to the prestressed strip via pull rings, used to apply prestress to the reinforced concrete lining layer. The air storage space is equipped with a pressure sensor for real-time monitoring of the air pressure inside the chamber. The pressure sensor and each hydraulic rod are connected to a controller. The controller receives the detection signal from the pressure sensor and adjusts the tension of each hydraulic rod according to the detection signal, so that the reinforced concrete lining layer is always under pressure.

2. The prestressed tie rod type compressed air storage structure as described in claim 1, characterized in that, The reinforced concrete lining layer is assembled from multiple precast reinforced concrete segments, wherein the concrete in the precast reinforced concrete segments is ECC concrete.

3. The prestressed tie rod type compressed air storage structure as described in claim 2, characterized in that, The precast reinforced concrete segments have splicing joints at the joint locations, and grouting material is injected into the splicing joints.

4. The prestressed tie rod type compressed air storage structure as described in claim 1, characterized in that, The buffer layer is a butyl rubber pad with a thickness of 5mm to 10mm.

5. The prestressed tie rod type compressed air storage structure as described in claim 1, characterized in that, The sealing layer is a polymer coating with a thickness of 5mm to 10mm.

6. The prestressed tie rod type compressed air storage structure as described in claim 1, characterized in that, The thickness of the reinforced concrete lining layer is 30cm to 40cm.

7. The prestressed tie rod type compressed air storage structure as described in claim 1, characterized in that, The thickness of the shotcrete layer is 15cm to 25cm.

8. The prestressed tie rod type compressed air storage structure as described in claim 5, characterized in that, The polymer coating contains polyurea-formaldehyde microcapsules, which encapsulate an epoxy resin repair agent.

9. The prestressed tie rod type compressed air storage structure as described in claim 1, characterized in that, Strain sensors are evenly distributed on the inner and outer sides of the reinforced concrete lining layer, and the strain sensors are connected to the controller. The controller obtains the adjustment command of each hydraulic tie rod according to the air pressure in the air storage space, and calculates the bending strain based on the inner and outer strain sensors of each control section. Based on the comparison of the bending strain with a preset threshold, a local correction tension command for the hydraulic tie rod of that section is generated. The adjustment command and the local correction tension command are superimposed to generate the final tension command for each hydraulic tie rod. According to the final tension command, the tension of the corresponding hydraulic tie rod is adjusted so that the reinforced concrete lining layer is under a state of predominant compressive stress, both as a whole and locally.

Images