Prestress block type compressed air energy storage underground cavern

Abstract

The prestressed block type compressed air energy storage underground cavern comprises a primary lining, a sliding layer, a reinforced concrete lining and a flexible sealing layer, the reinforced concrete lining comprises a plurality of reinforced concrete linings in the circumferential direction, and a preset seam is formed between every two adjacent reinforced concrete linings; annular steel bars of every two adjacent reinforced concrete linings are broken at the preset seams and are arranged in a staggered mode, and steel bar heads with certain lengths at the two ends of each annular steel bar are smeared with anti-friction agents or wrapped with isolation films respectively and penetrate through the corresponding preset seams to stretch into the adjacent reinforced concrete linings respectively. A plurality of grouting pipes and a plurality of exhaust pipes are embedded in the reinforced concrete lining, and each preset seam is connected with the multiple grouting pipes and the multiple exhaust pipes. According to the cavern, circumferential prestress can be applied to the reinforced concrete lining, the bearing capacity of surrounding rock is fully utilized, the surrounding rock bears more loads, the effect of coordinated deformation is achieved, the cracking problem of the underground cavern in the use period is solved, the reinforcement ratio is reduced, and the manufacturing cost is saved.

Description

Technical Field

[0001] The present invention belongs to the technical field of compressed air energy storage underground caverns, and particularly relates to a prestressed segmented compressed air energy storage underground cavern. Background Art

[0002] The compressed air energy storage technology in underground caverns is a new type of environmentally friendly, safe and efficient long-term energy storage technology. Its technical feature is to compress air into an underground cavern for energy storage. Especially, the gas storage pressure in the underground cavern is relatively high, reaching dozens of megapascals. Therefore, it is necessary to rely on the strength of the surrounding rock to maintain the stability of the cavern structure. However, the existing underground gas storage caverns generally adopt an integral reinforced concrete storage tank structure. Most of the gas storage pressure is borne by the lining structure of the reinforced concrete storage tank. The deformation coordination of the cavern is poor, the load borne by the rock mass is limited, and there is a great risk of cracking in the concrete lining structure. This makes the concrete strength and reinforcement ratio of the lining structure generally high, and the cost is high. Moreover, the existing underground gas storage caverns generally have high requirements for the strength of the surrounding rock, which greatly limits the site selection range of compressed air energy storage power stations and restricts the development of the industry. Summary of the Invention

[0003] In order to make full use of the bearing capacity of underground rock mass, improve the deformation coordination of underground gas storage caverns, enhance the geological adaptability of underground gas storage caverns, reduce the application difficulty of compressed air energy storage technology, and at the same time alleviate the cracking problem of the reinforced concrete lining structure and reduce the cost, the present invention proposes a prestressed segmented compressed air energy storage underground cavern.

[0004] The technical solution adopted by the present invention to solve the above technical problems is as follows: a prestressed segmented compressed air energy storage underground chamber, which includes a primary lining, a sliding layer, a reinforced concrete inner lining, and a flexible sealing layer arranged in sequence from the outside to the inside along the chamber wall of the underground chamber. The circumferential direction of the reinforced concrete inner lining includes multiple reinforced concrete linings. A preset joint is provided between two adjacent reinforced concrete linings. Each of the preset joints is arranged longitudinally and continuously along the longitudinal direction of the reinforced concrete inner lining. The circumferential steel bars of two adjacent reinforced concrete linings are disconnected and staggered at the preset joint. The two ends of the circumferential steel bars of each reinforced concrete lining with a certain length of steel bar heads are respectively coated with an anti-friction agent or covered with an isolation film. The two ends of the circumferential steel bars of each reinforced concrete lining with a certain length of steel bar heads respectively pass through the corresponding preset joint and extend into the adjacent reinforced concrete lining. Multiple grouting pipes and multiple exhaust pipes are buried in the reinforced concrete inner lining. Each of the preset joints is respectively connected to several grouting pipes and several exhaust pipes. After the construction of the underground chamber and its supporting facilities is completed, the underground chamber is filled with gas for the first time, and each preset joint gradually opens. When the internal air pressure of the underground chamber reaches 105-110% of the maximum value of the designed gas storage pressure and the opening amount of each preset joint is stable, grouting materials are injected into the corresponding preset joints by using several grouting pipes. During the grouting process, the gas in the corresponding preset joint is discharged to the outside of the underground chamber through several exhaust pipes.

[0005] The compressed air energy storage underground chamber of the present invention adopts a reinforced concrete inner lining with preset joints. The circumferential steel bars of two adjacent reinforced concrete linings are disconnected and staggered at the preset joint, and the two ends of the circumferential steel bars of each reinforced concrete lining with a certain length of steel bar heads are respectively coated with an anti-friction agent or covered with an isolation film. When the internal air pressure of the underground chamber increases during the air filling stage of the first gas storage, the steel bar heads with a certain length coated with an anti-friction agent or covered with an isolation film on both sides of the preset joint can respectively separate from the opposite reinforced concrete lining, thereby allowing the circumferential opening of the reinforced concrete inner lining and the circumferential steel bars at the preset joint. The circumferential deformation of the reinforced concrete inner lining increases, further squeezing the surrounding rock outside the reinforced concrete inner lining, enabling the surrounding rock to bear more loads and achieving the effect of coordinated deformation. The reinforcement ratio of the reinforced concrete inner lining can be reduced under the same gas storage pressure, saving costs.

[0006] The number of preset joints will affect the deformation coordination ability of the reinforced concrete inner lining. Theoretically, the more preset joints, the better the deformability and coordination of the reinforced concrete inner lining. However, the number of preset joints in actual construction design should be comprehensively considered according to factors such as surrounding rock conditions, construction conditions, gas storage pressure, and technical conditions.

[0007] In the reinforced concrete lining of the underground chamber for compressed air energy storage of the present invention, grouting pipes and exhaust pipes are embedded. For the first air storage in the underground chamber, during the air filling stage, the internal pressure of the underground chamber gradually increases, and each preset joint gradually opens. After the internal air pressure of the underground chamber reaches 105-110% of the maximum value of the designed air storage pressure and the opening amount of each preset joint is stable, grouting materials can be injected into the corresponding preset joints through the grouting pipes. After the grouting materials solidify, the reinforced concrete lining maintains the structural form under the action of the maximum internal and external pressures. Subsequently, when the internal pressure decreases, the reinforced concrete lining generates circumferential prestress, and the surrounding rock and the reinforced concrete lining always maintain a high-pressure stress state, so that the deformation amount of the reinforced concrete lining under both high-pressure and low-pressure states is greatly reduced. Thus, the deformation and cracks generated under the action of the internal pressure cyclic load during the normal use state of the underground chamber for compressed air energy storage are reduced, and further, the flexible sealing layer is protected to avoid the trap joint failure of the flexible sealing layer, and the entire underground chamber structure is safer and more reliable.

[0008] As the outermost layer of the underground chamber for compressed air energy storage, the primary lining plays a supporting role in the initial stage of excavating the underground surrounding rock to form the chamber, preventing the surrounding rock from collapsing and making the shape of the chamber more regular; the sliding layer plays an isolating and lubricating role, enabling the reinforced concrete lining to be free from the restraint of the friction of the outer primary lining, which is beneficial to the opening of the preset joints; the flexible sealing layer mainly plays a sealing role and generally uses materials such as rubber with good sealing performance, ductility, and durability.

[0009] Preferably, the flexible sealing layer is covered on the inner surface of the reinforced concrete lining, and a metal baffle is covered on the inner side of each preset joint. The metal baffle is arranged longitudinally and continuously along each preset joint, and the metal baffle is fixed to one piece of the reinforced concrete lining and is arranged outside the flexible sealing layer. The metal baffle is used to block the preset joints that open in the air-filled state and prevent the flexible sealing layer from falling into the preset joints.

[0010] Preferably, the plurality of grouting pipes are arranged at intervals longitudinally along the reinforced concrete lining, and the plurality of grouting pipes are respectively connected to a grouting main pipe. The grouting main pipe is arranged longitudinally and continuously along the reinforced concrete lining, and the inlet section of the grouting main pipe passes through the chamber plugging body and is connected to the grouting material supply mechanism outside the underground chamber.

[0011] Preferably, the inlet section of the grouting main pipe is arranged in the middle of the longitudinal direction of the reinforced concrete lining. An exhaust pipe is connected to each end of each preset joint. During the grouting process, when the grouting material flows out of the exhaust pipe at the farthest end of all preset joints, it is determined that all preset joints are filled with the grouting material, and the grouting is stopped and all exhaust pipes and the grouting main pipe are blocked. During the grouting process, the grouting material flows into each preset joint from the middle and flows to both sides, and finally reaches both ends of each preset joint. Therefore, we use whether the grouting material flows out of the exhaust pipe at the farthest end of all preset joints as the signal for stopping grouting, which is simple and reliable in operation.

[0012] Preferably, a roadway is provided on one side of the underground chamber, and the chamber seal is arranged at the roadway.

[0013] Compared with the prior art, the present invention has the following advantages: The compressed air energy storage underground chamber of the present invention can apply circumferential prestress to the reinforced concrete lining, make full use of the bearing capacity of the surrounding rock, enable the surrounding rock to bear more loads, achieve the effect of coordinated deformation, reduce the cracking problem of the underground chamber during use, reduce the reinforcement ratio of the reinforced concrete lining under the same gas storage pressure, save costs, enhance the geological adaptability of the underground gas storage, and reduce the application difficulty of the compressed air energy storage technology. Description of the Drawings

[0014] Figure 1 It is a cross-sectional schematic diagram (including the surrounding rock) of the prestressed segmented compressed air energy storage underground chamber in Embodiment 1;

[0015] Figure 2 It is Figure 1 The enlarged view at A in

[0016] Figure 3 It is a longitudinal-sectional schematic diagram (excluding the surrounding rock) of the prestressed segmented compressed air energy storage underground chamber in Embodiment 1;

[0017] Figure 4 It is a cross-sectional schematic diagram (including the surrounding rock) of the prestressed segmented compressed air energy storage underground chamber in Embodiment 2;

[0018] Figure 5 It is a longitudinal-sectional schematic diagram (excluding the surrounding rock) of the prestressed segmented compressed air energy storage underground chamber in Embodiment 2;

[0019] The specific reference numerals in the drawings are as follows:

[0020] 1 - primary lining, 2 - sliding layer, 3 - reinforced concrete lining, 31 - reinforced concrete lining, 32 - preset joint, 33 - chamber seal, 34 - roadway, 4 - flexible sealing layer, 5 - circumferential steel bars, 6 - grouting pipe, 61 - grouting main pipe, 62 - inlet section, 7 - exhaust pipe, 8 - metal baffle, 9 - surrounding rock. Detailed implementation mode

[0021] The present invention will be further described in detail below in conjunction with the embodiments in the accompanying drawings. Components or structures not defined in the present invention all adopt the prior art.

[0022] Embodiment 1: A prestressed segmented compressed air energy storage underground chamber, as Figures 1 to 3 shown, the underground chamber includes a primary lining 1, a sliding layer 2, a reinforced concrete inner lining 3, and a flexible sealing layer 4 arranged in sequence from the outside to the inside along the chamber wall of the underground chamber. The circumferential direction of the reinforced concrete inner lining 3 includes two semi-cylindrical reinforced concrete linings 31, an upper one and a lower one. A preset seam 32 is provided between two adjacent reinforced concrete linings 31. Each preset seam 32 is arranged longitudinally throughout the length of the reinforced concrete inner lining 3. The circumferential steel bars 5 of two adjacent reinforced concrete linings 31 are disconnected and staggeredly arranged at the preset seam 32. Anti-friction agents are respectively applied to the steel bar heads at both ends of a certain length of the circumferential steel bar 5 of each reinforced concrete lining 31, or isolation films are coated thereon. The steel bar heads at both ends of a certain length of the circumferential steel bar 5 of each reinforced concrete lining 31 respectively pass through the corresponding preset seam 32 and extend into the adjacent reinforced concrete lining 31. A plurality of grouting pipes 6 and a plurality of exhaust pipes 7 are embedded in the reinforced concrete inner lining 3. Each preset seam 32 is respectively connected to a plurality of grouting pipes 6 and a plurality of exhaust pipes 7.

[0023] In Embodiment 1, the flexible sealing layer 4 is laid on the inner surface of the reinforced concrete inner lining 3. A metal baffle 8 is covered on the inner side of each preset seam 32. The metal baffle 8 is arranged longitudinally throughout the length of each preset seam 32. The metal baffle 8 is fixed to one of the reinforced concrete linings 31 and is arranged outside the flexible sealing layer 4.

[0024] In Embodiment 1, a plurality of grouting pipes 6 are arranged at intervals longitudinally along the reinforced concrete inner lining 3. A plurality of grouting pipes 6 are respectively connected to a grouting main pipe 61. The grouting main pipe 61 is arranged longitudinally throughout the length of the reinforced concrete inner lining 3. The inlet section 62 of the grouting main pipe 61 passes through the chamber plug 33 and is connected to a grouting material supply mechanism outside the underground chamber. A roadway 34 is provided on one side of the underground chamber. The chamber plug 33 is arranged at the roadway 34; the inlet section 62 of the grouting main pipe 61 is arranged in the middle longitudinally of the reinforced concrete inner lining 3. Both ends of each preset seam 32 are respectively connected to an exhaust pipe 7.

[0025] After the construction of the underground chamber and its supporting facilities in the above Embodiment 1 is completed, the underground chamber is filled with gas for the first time. Each preset seam 32 gradually opens. After the internal air pressure of the underground chamber reaches 105 - 110% of the maximum value of the designed gas storage pressure and the opening amount of each preset seam 32 is stable, grouting materials are injected into the corresponding preset seam 32 by using a plurality of grouting pipes 6. During the grouting process, the gas in the corresponding preset seam 32 is discharged to the outside of the underground chamber through a plurality of exhaust pipes 7.

[0026] In a specific application case, the construction and grouting method of the underground chamber in the above-mentioned Embodiment 1 is as follows:

[0027] In the first step, construct the primary lining 1. During the process of gradually excavating the rock and soil mass using the roadway 34, construct the primary lining 1 while excavating until the design requirements of the gas storage cavern are met;

[0028] In the second step, construct the sliding layer 2. Grind the inner wall of the primary lining 1 to make it as flat and smooth as possible, and then construct the sliding layer 2 on the surface of the primary lining 1 until the sliding layer 2 covers the entire inner wall of the primary lining 1 and the thickness reaches the design requirements;

[0029] In the third step, construct the reinforced concrete lining 3 with a preset joint 32. During the stage of tying the steel bars, embed the grouting pipe 6 and the exhaust pipe 7 in the reinforced concrete lining 3. The circumferential steel bars 5 of two adjacent reinforced concrete linings 31 are disconnected and staggered at the preset joint 32, and at both ends of the circumferential steel bars 5 of each reinforced concrete lining 31, the steel bar heads with a certain length are respectively smeared with an anti-friction agent or coated with an isolation film. Pour the reinforced concrete lining 31 by using the single-side formwork method. First, construct the lower half of the reinforced concrete lining 31, and then construct the upper half of the reinforced concrete lining 31, and set an isolation layer at the preset joint 32, which not only protects the pipe orifices of the grouting pipe 6 and the exhaust pipe 7 to prevent concrete blockage, but also ensures the mutual isolation of the two semi-cylindrical reinforced concrete linings 31 up and down, preventing the opening surface of the preset joint 32 from being uneven or difficult to open;

[0030] In the fourth step, construct the flexible sealing layer 4. When the two upper and lower reinforced concrete linings 31 reach the strength requirements, construct the metal baffle 8 at the preset joint 32. The metal baffle 8 is only connected to the upper half or the lower half of the reinforced concrete lining 31, and its strength should be sufficient to resist the design air pressure in the cavern. At the same time, its thickness should be as thin as possible, and the edge is rounded to prevent piercing the flexible sealing layer 4. Lubricating oil can be set between the flexible sealing layer 4 and the metal baffle 8 to prevent adhesion;

[0031] Step 5: After the construction of the underground chamber and its supporting facilities (such as compressed air energy storage power station) is completed, the underground chamber is subjected to the first gas storage. Each preset seam 32 gradually opens, and the steel bar heads of a certain length coated with anti-friction agent or covered with isolation film on both sides of each preset seam 32 are separated from the reinforced concrete lining 31 on the opposite side respectively. The circumferential deformation of the reinforced concrete inner lining 3 increases, further squeezing the surrounding rock 9 outside the reinforced concrete inner lining 3, so that the surrounding rock 9 bears more loads, achieving the effect of coordinated deformation. After the internal air pressure of the underground chamber reaches 105-110% of the maximum value of the designed gas storage pressure and the opening amount of each preset seam 32 is stable (it can be observed for 24 hours first), grouting material is injected into the grouting main pipe 61, so that the grouting material flows in from the middle of each preset seam 32 and flows to both sides, and finally reaches both ends of each preset seam 32. When the grouting material flows out of the exhaust pipe 7 at the farthest end of all preset seams 32, it is judged that all preset seams 32 are filled with grouting material, and the grouting is stopped and all exhaust pipes 7 and grouting main pipes 61 are blocked.

[0032] After the grouting material solidifies, the reinforced concrete inner lining 3 is in the structural form under the action of the maximum internal and external pressures, and the compressed air energy storage underground chamber can be put into normal use. Subsequently, when the internal pressure decreases, the reinforced concrete inner lining 3 generates circumferential prestress, and the surrounding rock 9 and the reinforced concrete inner lining 3 always maintain a high-pressure stress state, so that the deformation amount of the reinforced concrete inner lining 3 under both high-pressure and low-pressure states is greatly reduced, thereby reducing the deformation and cracks generated under the action of the internal pressure cyclic load during the normal use of the compressed air energy storage underground chamber, further protecting the flexible sealing layer 4, avoiding the trap seam failure of the flexible sealing layer 4, making the entire underground chamber structure safer and more reliable, and reducing the reinforcement ratio of the reinforced concrete inner lining 3 under the same gas storage pressure, saving the cost.

[0033] The grouting material can adopt existing commercially available products, including organic, inorganic or mixed grouting materials. In Example 1, the grouting material is ultra-fine concrete with a strength greater than C40.

[0034] Example 2: The prestressed segmented compressed air energy storage underground chamber is different from that in Example 1 in that, as Figures 4 to 5 shown, in Example 2, the reinforced concrete inner lining 3 includes three pieces of reinforced concrete linings 31, namely, the upper, middle and lower ones. From the cross-section of the chamber, the reinforced concrete inner lining 3 is divided into four parts, increasing the deformation coordination of the reinforced concrete inner lining 3. The increase of the preset seams 32 makes the deformation amount of each preset seam 32 smaller, thus reducing the grouting duration, and the layout of the grouting pipes 6 is more concise, which further reduces the grouting difficulty.

[0035] The construction method of the prestressed segmented compressed air energy storage underground chamber in Example 2 is the same as that in Example 1.

Claims

1. A prestressed segmented compressed air energy storage underground chamber, which comprises a primary lining, a sliding layer, a reinforced concrete inner lining and a flexible sealing layer arranged in sequence from outside to inside along the wall of the underground chamber, and is characterized in that, The circumferential direction of the reinforced concrete lining includes multiple reinforced concrete linings. A preset joint is provided between two adjacent reinforced concrete linings. Each of the preset joints is arranged longitudinally throughout the length of the reinforced concrete lining. The circumferential steel bars of two adjacent reinforced concrete linings are disconnected and stagger-arranged at the preset joint. The ends of the circumferential steel bars of each reinforced concrete lining with a certain length are respectively coated with an anti-friction agent or covered with an isolation film. The ends of the circumferential steel bars of each reinforced concrete lining with a certain length respectively pass through the corresponding preset joint and extend into the adjacent reinforced concrete lining. A plurality of grouting pipes and a plurality of exhaust pipes are buried in the reinforced concrete lining. Each of the preset joints is respectively connected to a plurality of grouting pipes and a plurality of exhaust pipes. After the construction of the underground chamber and its supporting facilities is completed, the underground chamber is filled with gas for the first time. Each preset joint gradually opens. When the internal air pressure of the underground chamber reaches 105-110% of the maximum value of the designed gas storage pressure and the opening amount of each preset joint is stable, grouting material is injected into the corresponding preset joint by using a plurality of grouting pipes. During the grouting process, the gas in the corresponding preset joint is discharged to the outside of the underground chamber through a plurality of exhaust pipes.

2. The prestressed block-type compressed air energy storage underground chamber according to claim 1, characterized in that, The flexible sealing layer is laid on the inner surface of the reinforced concrete lining. A metal baffle is covered on the inner side of each preset joint. The metal baffle is arranged longitudinally throughout the length of each preset joint. The metal baffle is fixed to one of the reinforced concrete linings. The metal baffle is arranged on the outer side of the flexible sealing layer.

3. The prestressed block-type compressed air energy storage underground chamber according to claim 1, wherein, The plurality of grouting pipes are arranged at intervals longitudinally along the reinforced concrete lining. The plurality of grouting pipes are respectively connected to a grouting main pipe. The grouting main pipe is arranged longitudinally throughout the length of the reinforced concrete lining. The inlet section of the grouting main pipe passes through the chamber sealing body and is connected to the grouting material supply mechanism outside the underground chamber.

4. The prestressed block-type compressed air energy storage underground chamber according to claim 3, wherein The inlet section of the grouting main pipe is arranged in the middle longitudinally of the reinforced concrete lining. An exhaust pipe is connected to each end of each preset joint. During the grouting process, when grouting material flows out from the exhaust pipes at the farthest ends of all preset joints, it is determined that all preset joints are filled with grouting material, and the grouting is stopped and all exhaust pipes and the grouting main pipe are blocked.

5. The prestressed segmented compressed air energy storage underground chamber according to claim 3, wherein A roadway is provided on one side of the underground chamber. The chamber sealing body is arranged at the roadway.

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