Flexible preset joint reinforced concrete lining structure of compressed air energy storage underground cavern

Abstract

The invention discloses a compressed air energy storage underground cavity flexible preset joint reinforced concrete lining structure which is characterized in that the cross section of a compressed air energy storage underground cavity is circular, two or more preset joints are preset in the longitudinal direction of the lining structure, and the lining structure comprises reinforced concrete linings poured in blocks; steel bars are embedded in each reinforced concrete lining, the steel bars of every two adjacent reinforced concrete linings are connected through a plurality of flexible steel bar connectors arranged at the corresponding preset joints, each preset joint is filled with a porous rubber pad, and the inner side of each preset joint is covered with a metal baffle. The surface of the metal baffle fixed to the lining structure is covered with a flexible sealing strip, the flexible sealing strip is fixed to the inner wall of the lining structure, and the inner wall of the lining structure is coated with a sealing material layer. The lining structure is high in deformability, the rated gas storage pressure of the cavern can be greatly increased, the stress of the lining is reduced, the load bearing ratio of surrounding rock is increased, the application range is wider, and the risk and cost are lower.

Description

Technical Field

[0001] The present invention relates to the technical field of underground energy storage, and particularly relates to a flexible pre-set joint reinforced concrete lining structure for an underground chamber of compressed air energy storage. Background Art

[0002] Large-scale energy storage technologies, including pumped-storage energy storage and compressed air energy storage, can solve the problems of intermittency and volatility of wind power and photovoltaic power. The pumped-storage energy storage technology is mature, but it is strictly restricted by geographical conditions and ecological environment protection. Compressed air energy storage is more flexible in site selection, has strong geological adaptability, and causes little ecological disturbance. Especially in regions rich in renewable energy such as the "Three-North Regions" of China, there is a large demand and broad prospects for its application. Compressed air energy storage is a commonly used large-scale energy storage technology. The compressed air energy storage technology uses high-pressure air as a medium to achieve the storage and release of energy in the power grid. By reasonably regulating the storage and release of energy, intermittent energy sources such as wind power and photovoltaic power can be converted into stable and controllable high-quality energy. Among them, the underground chamber, as a storage container for high-pressure air, plays an important role in the operation process of a compressed air energy storage power station. The key issues in its construction are the sealing problem of the underground chamber and the anti-cracking problem of the lining structure of the chamber under a high internal pressure environment.

[0003] The invention with the application number 201410174203.2 and the name "A construction method for a compressed air energy storage chamber", disclosed on September 3, 2014, discloses a construction method for a compressed air energy storage chamber using steel fiber reinforced concrete as the lining and applying a polymer material inside as a sealing layer. Although the lining is applied in this method, the polymer material forms a sealing structure through splicing, and the air leakage rate is relatively large. The invention with the application number 202110665113.3 and the name "An underground chamber for compressed air energy storage with an integral rubber bladder seal", disclosed on June 16, 2021, discloses an underground chamber for compressed air energy storage with an integral rubber bladder seal. The chamber support structure is a reinforced concrete lining, and a whole rubber bladder is used as the sealing layer, and the volume of the sealing layer is slightly larger than the volume of the chamber. This method avoids the risk of the sealing layer being torn during the gas storage process, but the reinforced concrete lining still has a risk of tensile failure under a high internal pressure environment, and the lining will damage the flexible sealing material after being pulled and cracked. Therefore, the above-mentioned lining structure can bear a very low internal pressure, has poor anti-cracking performance of the lining structure, is not suitable for environments with poor surrounding rock conditions, and the rated gas storage pressure of the chamber is relatively low, and the applicable range is relatively limited. Summary of the Invention

[0004] To solve the anti-cracking design problem of the lining structure of compressed air energy storage caverns and overcome the situation where the concrete lining is damaged due to tension when the existing compressed air energy storage caverns store gas at high internal pressure, the present invention proposes a flexible pre-set joint reinforced concrete lining structure for underground compressed air energy storage caverns that is applicable to higher gas storage pressures, has better feasibility, and lower risks and costs.

[0005] The technical solution adopted by the present invention to solve the above technical problems is as follows: A flexible pre-set joint reinforced concrete lining structure for an underground compressed air energy storage cavern. The cross-section of the underground compressed air energy storage cavern is circular, and there are two or more pre-set joints longitudinally provided in its lining structure. The lining structure includes reinforced concrete linings cast in sections. Reinforcing bars are embedded in each reinforced concrete lining. The reinforcing bars of adjacent two reinforced concrete linings are connected by a number of flexible reinforcing bar joints. The number of flexible reinforcing bar joints is provided at the corresponding pre-set joints. Each pre-set joint is filled with a porous rubber pad. A metal baffle is covered on the inner side of each pre-set joint. The metal baffle is fixed to the lining structure. A flexible sealing strip is covered on the surface of the metal baffle. The flexible sealing strip is fixed to the inner wall of the lining structure. A sealing material layer is painted on the inner wall of the lining structure.

[0006] Before the underground cavern stores gas, under the action of the gravity of the lining structure, the porous rubber pads and a number of flexible reinforcing bar joints are in a compressed state, the pre-set joints are closed, and the flexible sealing strips are in a relaxed state where they are not fully attached to the inner wall of the lining structure.

[0007] During the gas storage process of the underground cavern, the internal pressure in the underground cavern gradually increases, the pre-set joints gradually open, the porous rubber pads gradually expand, a number of flexible reinforcing bar joints gradually elongate, and the flexible sealing strips are gradually stretched to closely adhere to the inner wall of the lining structure. In the high internal pressure state after gas storage is completed, the lining structure is deformed under tension, and the lining structure is not subjected to tension or is subjected to very small tension in the circumferential direction.

[0008] During the gas discharge process of the underground cavern, as the internal pressure in the underground cavern decreases, the pre-set joints gradually shrink, the porous rubber pads and a number of flexible reinforcing bar joints are gradually compressed, the flexible sealing strips gradually contract and separate from the inner wall of the lining structure, and the lining structure gradually bears the external surrounding rock load.

[0009] In the lining structure of the present invention, the flexible reinforcing bar joints are used to connect the reinforcing bars at the pre-set joints to realize the connection between the reinforced concrete lining blocks. The pre-set joints are filled with porous rubber pads, which not only increase the sealing performance at the pre-set joints but also play a buffering role. The function of the flexible sealing strip is to seal the pre-set joints, and the function of the metal baffle is to prevent the flexible sealing strip from being squeezed into the pre-set joints under high internal pressure and thus causing sealing failure.

[0010] Due to the existence of the preset joint and the flexible steel bar joint, the lining structure of the present invention is basically not in tension under the high internal pressure environment. Therefore, there is no need to consider that the sealing material layer coated on the inner wall of the lining structure will be torn due to tension. During the maintenance condition, the lining structure can bear the external surrounding rock load.

[0011] Preferably, each of the flexible steel bar joints includes a first sleeve, a second sleeve, a third sleeve and a high-strength bolt. The two ends of the first sleeve are respectively threadedly connected to a section of the steel bar and the small head end of the high-strength bolt. The two ends of the second sleeve are respectively threadedly connected to another section of the steel bar and the third sleeve. The small head end of the high-strength bolt penetrates through the third sleeve. The large head end of the high-strength bolt is installed in the second sleeve with a clearance fit, and the large head end of the high-strength bolt can slide in the second sleeve. Each of the flexible steel bar joints penetrates through a corresponding porous rubber pad. During the gas storage process, as the internal pressure in the underground cavity increases, the preset joint gradually opens, the large head end of the high-strength bolt slides in the second sleeve, and the flexible steel bar joint is gradually stretched until the opening amount of the preset joint reaches the maximum value. During the deflation process, as the internal pressure in the underground cavity decreases, the preset joint is gradually compressed and reduced, the large head end of the high-strength bolt slides in the second sleeve, and the flexible steel bar joint is gradually shortened until the preset joint closes.

[0012] Preferably, a flexible washer is arranged on the surface of the large head end of the high-strength bolt facing the third sleeve. When the internal pressure in the cavity increases, the flexible washer can reduce the impact force when the flexible steel bar joint is suddenly in tension, playing a buffering effect.

[0013] Preferably, the inner wall of the first sleeve is provided with internal threads. The two ends of the inner wall of the second sleeve are provided with internal threads and the middle part is smooth. The outer wall of the third sleeve is provided with external threads. The second sleeve, the third sleeve and another section of the steel bar enclose a closed cavity. The large head end of the high-strength bolt is installed in the cavity with a clearance fit, and the large head end of the high-strength bolt can slide in the cavity. The outer end surface of the third sleeve is flush with one end surface of the second sleeve. The small head end of the high-strength bolt penetrates through the corresponding porous rubber pad, and the first sleeve, the second sleeve and the third sleeve clamp the corresponding porous rubber pad.

[0014] Preferably, the upper end of the metal baffle is fixed to the inner wall of the lining structure by screws, and the lower side of the metal baffle abuts against the inner wall of the lining structure. The upper end of the metal baffle is fixed to the inner wall of the lining structure and the lower end is free.

[0015] Preferably, the groove between the outer side of the screw head of the screw and the metal baffle is filled with latex to prevent the groove on the metal baffle and the screw head from damaging the flexible sealing strip under the action of high internal pressure.

[0016] Preferably, a thin angle steel is provided between the inner wall of the lining structure and the lower side of the metal baffle, and the thin angle steel is fixed at the corner of the inner wall of the lining structure and the corresponding preset joint. The function of the thin angle steel is to reduce the friction between the lower side of the metal baffle and the inner wall of the lining structure.

[0017] Preferably, the lower side of the thin angle steel is located below the bottom end of the metal baffle, the flexible sealing strip covers the surfaces of the lower sides of the metal baffle and the thin angle steel, and both ends of the flexible sealing strip are fixed to the inner walls of two adjacent reinforced concrete linings through pressing plates respectively.

[0018] Preferably, the steel bars embedded in each reinforced concrete lining include inner steel bars and outer steel bars, and the inner steel bars and outer steel bars between two adjacent reinforced concrete linings are connected by a plurality of flexible steel bar joints respectively.

[0019] Preferably, a plurality of flexible steel bar joints located at the same preset joint are at the same horizontal height to ensure uniform force on the preset joint and the flexible steel bar joints.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1) The present invention enables the deformation of the lining structure to be fully released through the preset joint, and at the same time, flexible steel bar joints are provided at the preset joint for connecting the steel bars at the preset joint, which can control the maximum opening amount at the preset joint and ensure the overall stability of the lining structure. When the internal pressure increases during gas storage in the compressed air energy storage underground chamber of the present invention, the lining structure is not subjected to tensile force or is subjected to very small tensile force in the circumferential direction, and the tensile deformation is mainly contributed by the preset joint and the flexible steel bar joints, largely avoiding the tensile failure of the lining structure and greatly improving the safety and durability of the compressed air energy storage underground chamber.

[0022] 2) The present invention seals at the preset joint by using a flexible sealing strip, and protects the flexible sealing strip through a metal baffle to prevent the flexible sealing strip from being extruded into the preset joint under the action of high internal pressure and then causing the sealing to fail. When the internal pressure in the chamber changes, the flexible steel bar joints undergo tensile and compressive displacements, and at this time, the state of the porous rubber pad also changes accordingly, which can play a good sealing role. Except for the preset joint, only a layer of sealing material layer needs to be painted on the inner wall of the lining structure to ensure the overall sealing effect of the chamber. Due to the existence of the preset joint, the lining structure is basically not subjected to tensile force in a high internal pressure environment, so there is no need to consider the sealing material being torn due to tension.

[0023] 3) The lining structure of the present invention is simple, the flexible steel bar joints are prefabricated parts, only installation is required on site, the manufacturing cost is low, the construction is convenient, it is easy to implement and promote, and the economic benefit is high.

[0024] 4) Compared with the existing underground chambers for compressed air energy storage, the lining structure of the underground chamber for compressed air energy storage of the present invention has strong deformation ability, can greatly increase the rated gas storage pressure of the chamber, reduce the stress on the lining at the same time, and improve the load-bearing ratio of the surrounding rock. Compared with the traditional steel lining and integral ring concrete lining, the lining structure of the present invention has a wider application range, better feasibility in geological environments with poor surrounding rock conditions, and lower risks and costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic cross-sectional view of the lining structure in the embodiment;

[0026] Figure 2 It is a schematic diagram of the effect after the flexible steel bar joint is installed at the preset joint in the embodiment;

[0027] Figure 3 It is a schematic longitudinal sectional view of a single flexible steel bar joint in the embodiment;

[0028] Figure 4 It is a schematic diagram of the open state of the preset joint in the embodiment under the gas storage condition;

[0029] Figure 5 It is a schematic diagram of the closed state of the preset joint in the embodiment under the gas release condition;

[0030] The specific reference numerals in the figure are as follows:

[0031] 1 - Reinforced concrete lining, 2 - Inner steel bars, 3 - Outer steel bars, 4 - Porous rubber pad, 5 - Flexible steel bar joint, 6 - Flexible sealing strip, 7 - Pressure plate, 8 - Metal baffle, 9 - Screw, 10 - First sleeve, 11 - Second sleeve, 12 - Third sleeve, 13 - Flexible washer, 14 - High-strength bolt, 15 - Thin angle steel, 16 - Latex, 17 - Cavity, 18 - Preset joint. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0033] Embodiment: A flexible preset joint reinforced concrete lining structure for an underground chamber for compressed air energy storage. The underground chamber for compressed air energy storage is excavated in underground surrounding rock with poor integrity. The cross-section of the underground chamber for compressed air energy storage is circular, as Figures 1 to 3As shown in the figure, there are two preset joints 18 longitudinally preset in the lining structure. The lining structure includes a reinforced concrete lining 1 cast in blocks at the construction site. Reinforcing bars are embedded in each block of the reinforced concrete lining 1. The reinforcing bars of two adjacent blocks of the reinforced concrete lining 1 are connected by a number of flexible reinforcing bar joints 5. The number of flexible reinforcing bar joints 5 is arranged at the corresponding preset joints 18. A porous rubber pad 4 is filled at each preset joint 18. A metal baffle 8 is covered on the inner side of each preset joint 18. The upper end of the metal baffle 8 is fixed to the inner wall of the lining structure by a screw 9. A flexible sealing strip 6 is covered on the surface of the metal baffle 8. The flexible sealing strip 6 is fixed to the inner wall of the lining structure. A sealing material layer (not shown in the figure) is painted on the inner wall of the lining structure.

[0034] In this embodiment, each flexible reinforcing bar joint 5 includes a first sleeve 10, a second sleeve 11, a third sleeve 12 and a high-strength bolt 14. The two ends of the first sleeve 10 are respectively threadedly connected to a section of reinforcing bar and the small head end of the high-strength bolt 14. The two ends of the second sleeve 11 are respectively threadedly connected to another section of reinforcing bar and the third sleeve 12. The small head end of the high-strength bolt 14 passes through the third sleeve 12. The large head end of the high-strength bolt 14 is installed in the second sleeve 11 with a clearance fit. The large head end of the high-strength bolt 14 can slide in the second sleeve 11. A flexible washer 13 is arranged on the surface of the large head end of the high-strength bolt 14 facing the third sleeve 12. Specifically, the inner wall of the first sleeve 10 is provided with internal threads. The two ends of the inner wall of the second sleeve 11 are provided with internal threads and the middle part is smooth. The outer wall of the third sleeve 12 is provided with external threads. The second sleeve 11, the third sleeve 12 and another section of reinforcing bar enclose a closed cavity 17. The large head end of the high-strength bolt 14 is installed in the cavity 17 with a clearance fit. The large head end of the high-strength bolt 14 can slide in the cavity 17. The outer end surface of the third sleeve 12 is flush with one end surface of the second sleeve 11. The small head end of the high-strength bolt 14 passes through the corresponding porous rubber pad 4. The first sleeve 10 and the second sleeve 11 and the third sleeve 12 clamp the corresponding porous rubber pad 4.

[0035] In this embodiment, the groove between the outer side of the screw cap of the screw 9 and the metal baffle 8 is filled with latex 16. A thin angle steel 15 is arranged between the inner wall of the lining structure and the lower side of the metal baffle 8. The thin angle steel 15 is fixed at the corner of the inner wall of the lining structure and the corresponding preset joint 18. The lower side of the thin angle steel 15 is located below the bottom end of the metal baffle 8. The flexible sealing strip 6 covers the surfaces of the lower sides of the metal baffle 8 and the thin angle steel 15. The two ends of the flexible sealing strip 6 are respectively fixed to the inner walls of two adjacent blocks of the reinforced concrete lining 1 by pressing plates 7.

[0036] In this embodiment, the steel bars embedded in each reinforced concrete lining 1 include inner steel bars 2 and outer steel bars 3. The inner steel bars 2 and the outer steel bars 3 between two adjacent reinforced concrete linings 1 are respectively connected by a number of flexible steel bar joints 5. A number of flexible steel bar joints 5 located at the same preset joint 18 are at the same horizontal height.

[0037] Before the underground chamber stores gas, under the action of the gravity of the lining structure, the porous rubber pads 4 and a number of flexible steel bar joints 5 are in a compressed state, the preset joint 18 is closed, and the flexible sealing strip 6 is in a relaxed state where it is not fully attached to the inner wall of the lining structure.

[0038] As Figure 4 shown, during the gas storage process of the underground chamber, the internal pressure in the underground chamber gradually increases, the preset joint 18 gradually opens, the porous rubber pads 4 gradually expand, the flexible sealing strip 6 is gradually stretched, the large head end of the high-strength bolt 14 slides in the second sleeve 11, and a number of flexible steel bar joints 5 are gradually stretched until the opening amount of the preset joint 18 reaches the maximum value. At this time, the flexible sealing strip 6 closely adheres to the inner wall of the lining structure. In the high internal pressure state after gas storage is completed, the lining structure is deformed under tension. At this time, the tensile deformation of the lining structure is mainly contributed by the preset joint 18 and the flexible steel bar joints 5, largely avoiding the tensile failure of the lining structure.

[0039] As Figure 5 shown, during the gas release process of the underground chamber, as the internal pressure in the underground chamber decreases, the preset joint 18 gradually shrinks, the flexible sealing strip 6 gradually contracts, the porous rubber pads 4 and a number of flexible steel bar joints 5 are gradually compressed, the large head end of the high-strength bolt 14 slides in the second sleeve 11, and a number of flexible steel bar joints 5 are gradually shortened until the preset joint 18 is closed. At this time, the flexible sealing strip 6 is separated from the inner wall of the lining structure, and the lining structure gradually bears the external surrounding rock load.

Claims

1. A flexible pre - set joint reinforced concrete lining structure for an air - compressed energy storage underground chamber, characterized in that, The cross-section of the underground chamber for compressed air energy storage is circular, and there are two or more preset joints longitudinally provided in the lining structure. The lining structure includes reinforced concrete linings cast in blocks. Reinforcing bars are embedded in each block of the reinforced concrete lining, and the reinforcing bars of adjacent two blocks of reinforced concrete linings are connected by a number of flexible reinforcing bar joints. The number of flexible reinforcing bar joints is arranged at the corresponding preset joints. Each preset joint is filled with a porous rubber pad, and a metal baffle is covered on the inner side of each preset joint. The metal baffle is fixed to the lining structure, and a flexible sealing strip is covered on the surface of the metal baffle. The flexible sealing strip is fixed to the inner wall of the lining structure, and a sealing material layer is painted on the inner wall of the lining structure; Before the underground chamber stores gas, under the action of the gravity of the lining structure, the porous rubber pad and a number of flexible reinforcing bar joints are in a compressed state, the preset joints are closed, and the flexible sealing strip is in a relaxed state where it is not completely attached to the inner wall of the lining structure; During the gas storage process of the underground chamber, the internal pressure in the underground chamber gradually increases, the preset joints gradually open, the porous rubber pad gradually expands, a number of flexible reinforcing bar joints gradually elongate, and the flexible sealing strip is gradually stretched to closely adhere to the inner wall of the lining structure. In the high internal pressure state after gas storage is completed, the lining structure is in tensile deformation, and the lining structure is not subjected to tensile force or is subjected to very small tensile force in the circumferential direction; During the gas release process of the underground chamber, as the internal pressure in the underground chamber decreases, the preset joints gradually shrink, the porous rubber pad and a number of flexible reinforcing bar joints are gradually compressed, the flexible sealing strip gradually contracts and separates from the inner wall of the lining structure, and the lining structure gradually bears the external surrounding rock load.

2. The flexible pre-set joint reinforced concrete lining structure of an air-compressed energy storage underground chamber according to claim 1, characterized in that, Each flexible reinforcing bar joint includes a first sleeve, a second sleeve, a third sleeve and a high-strength bolt. The two ends of the first sleeve are respectively threadedly connected to a section of the reinforcing bar and the small head end of the high-strength bolt. The two ends of the second sleeve are respectively threadedly connected to another section of the reinforcing bar and the third sleeve. The small head end of the high-strength bolt penetrates through the third sleeve. The large head end of the high-strength bolt is installed in the second sleeve with a clearance fit. The large head end of the high-strength bolt can slide in the second sleeve. Each flexible reinforcing bar joint penetrates through the corresponding porous rubber pad.

3. The flexible pre-set joint reinforced concrete lining structure for an underground chamber of compressed air energy storage according to claim 2, wherein A flexible washer is arranged on the surface of the large head end of the high-strength bolt facing the third sleeve.

4. The flexible pre-set joint reinforced concrete lining structure of an underground chamber for compressed air energy storage according to claim 2, characterized in that The inner wall of the first sleeve is provided with internal threads. The two ends of the inner wall of the second sleeve are provided with internal threads and the middle part is smooth. The outer wall of the third sleeve is provided with external threads. The second sleeve, the third sleeve and another section of the reinforcing bar enclose a closed cavity. The large head end of the high-strength bolt is installed in the cavity with a clearance fit. The large head end of the high-strength bolt can slide in the cavity. The outer end face of the third sleeve is flush with one end face of the second sleeve. The small head end of the high-strength bolt penetrates through the corresponding porous rubber pad. The first sleeve and the second sleeve and the third sleeve clamp the corresponding porous rubber pad.

5. The flexible pre - set joint reinforced concrete lining structure of an air - compressed energy storage underground chamber according to claim 1, wherein, The upper end of the metal baffle is fixed to the inner wall of the lining structure by screws, and the lower side of the metal baffle abuts against the inner wall of the lining structure.

6. The flexible pre - set joint reinforced concrete lining structure of an air - compressed energy storage underground chamber according to claim 5, characterized in that, The groove between the outer side of the screw cap of the screw and the metal baffle is filled with latex.

7. The flexible pre - set joint reinforced concrete lining structure of an air - compressed energy storage underground chamber according to claim 5 or 6, characterized in that, A thin angle steel is provided between the inner wall of the lining structure and the lower side of the metal baffle, and the thin angle steel is fixed at the corner of the inner wall of the lining structure and the corresponding preset joint.

8. The flexible pre-set joint reinforced concrete lining structure of an air-compressed energy storage underground chamber according to claim 7, characterized in that, The lower side of the thin angle steel is located below the bottom end of the metal baffle, the flexible sealing strip covers the surfaces of the lower sides of the metal baffle and the thin angle steel, and both ends of the flexible sealing strip are respectively fixed to the inner walls of two adjacent reinforced concrete linings through pressing plates.

9. The flexible pre-set joint reinforced concrete lining structure for an air-compressed energy storage underground chamber according to claim 1, characterized in that, The steel bars embedded in each reinforced concrete lining include inner steel bars and outer steel bars, and the inner steel bars and outer steel bars between two adjacent reinforced concrete linings are respectively connected by a plurality of flexible steel bar joints.

10. A flexible pre-set joint reinforced concrete lining structure for an air-compressed energy storage underground chamber according to claim 9, characterized in that, A plurality of flexible steel bar joints located at the same preset joint are at the same horizontal height.

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