Compressed air energy storage warehouse composite toughness sealing lining structure and method

Abstract

The invention discloses a composite tough sealing lining structure and method for a compressed air energy storage reservoir, and relates to the technical field of compressed air energy storage, the sealing lining structure comprises a reinforced concrete layer, a flexible cushion layer and a glass fiber reinforced plastic layer which are sequentially arranged from outside to inside, and the reinforced concrete layer is arranged according to surrounding rock pressure and water pressure; the glass fiber reinforced plastic layer is used for sealing high-pressure air and bearing the internal pressure of the storage cavern, and the flexible cushion layer is used for reserving the deformation space of the glass fiber reinforced plastic layer, so that the formed composite toughness sealing lining structure and surrounding rock can be cooperatively stressed, the good sealing performance of the storage cavern is guaranteed, and the bearing capacity of the surrounding rock can be fully exerted.

Description

Technical Field

[0001] The present invention relates to the technical field of compressed air energy storage, and in particular to a composite tough sealing lining structure and method for a compressed air energy storage reservoir. Background Art

[0002] The compressed air energy storage reservoir seals and stores high-pressure gas through the collaborative force of the sealing lining structure and the surrounding rock, ensuring good stability of the gas storage reservoir. The current gas storage reservoir sealing structure is mainly a sealing structure based on steel plate sealing, which consists of a steel lining and a concrete lining and can effectively reduce the permeability; however, this structure has deficiencies. When the surrounding rock of the gas storage reservoir is soft rock, the modulus of steel is much greater than that of the surrounding rock, and the sealing structure bears most of the compressed air pressure, unable to fully exert the bearing capacity of the surrounding rock. Stress concentration is likely to occur at the contact between the steel lining and the surrounding rock, resulting in easier damage to the sealing layer and then sealing failure, affecting the long-term stability of the gas storage reservoir. Moreover, the direct contact between the concrete lining and the steel lining has a large friction and tangential force. During the long-term alternating process of high and low temperatures and the charging / discharging process of storage and release, it is easy to cause a decline in the performance of the concrete lining, such as cracks and spalling, affecting its structural safety and airtight performance. Summary of the Invention

[0003] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a composite tough sealing lining structure and method for a compressed air energy storage reservoir. The composite tough sealing lining structure can collaborate with the surrounding rock to ensure good sealing of the storage reservoir and can fully exert the bearing capacity of the surrounding rock itself.

[0004] To achieve the above purpose, the present invention is realized through the following technical solutions: In the first aspect, an embodiment of the present invention provides a composite tough sealing lining structure for a compressed air energy storage reservoir, including a reinforced concrete layer, a flexible cushion layer, and a fiberglass layer arranged in sequence from outside to inside. The reinforced concrete layer is set according to the surrounding rock pressure and water pressure. The fiberglass layer is used to seal high-pressure air and bear the internal pressure of the storage reservoir. The flexible cushion layer is used to reserve a deformation space for the fiberglass layer.

[0005] As a further implementation method, the cross-sections of the reinforced concrete layer, the flexible cushion layer, and the fiberglass layer are circular.

[0006] As a further implementation method, the elastic modulus of the reinforced concrete layer does not exceed the elastic modulus of the surrounding rock, and the elastic modulus of the flexible cushion layer is less than the elastic modulus of the surrounding rock.

[0007] In the second aspect, an embodiment of the present invention also provides a design method for a composite tough sealing lining structure of a compressed air energy storage reservoir, including: In the empty reservoir stage, based on the fact that the surrounding rock pressure and water pressure are all borne by the reinforced concrete layer, calculate the surrounding rock pressure and water pressure, and set the reinforced concrete layer accordingly. In the initial inflation stage, based on the fact that the initial inflation pressure is all borne by the fiberglass layer, and taking the thickness of the flexible cushion as the radial deformation of the fiberglass layer, calculate the initial inflation pressure and the internal pressure of the fiberglass layer. In the later inflation stage and the full reservoir operation stage, taking the increment of the full reservoir working pressure relative to the initial inflation pressure as the calculated load, calculate the forces on the fiberglass layer, the reinforced concrete layer and the surrounding rock, and judge whether damage occurs based on the forces; when the fiberglass layer and the reinforced concrete layer do not suffer damage and meet the set safety factor, obtain a sealed lining structure that meets the design requirements.

[0008] As a further implementation method, the calculation method of the surrounding rock pressure is as follows: First, determine the mechanical parameters of the surrounding rock, judge the surrounding rock grade, set the buried depth of the cavern, the gas storage scale, the full reservoir working pressure, and the excavation radius, and calculate the vertical surrounding rock pressure and the horizontal surrounding rock pressure. The calculation method of the water pressure is as follows: Obtain the acting head from the groundwater level line to the center of the cavern, and take the water pressure as the surface force acting on the outer boundary of the reinforced concrete layer to calculate the water pressure.

[0009] As a further implementation method, calculate the outer boundary deformation of the fiberglass layer when it bears the full reservoir working pressure. According to the equality of the thickness of the flexible cushion and the outer boundary deformation of the fiberglass layer, calculate the internal pressure borne by the fiberglass layer.

[0010] As a further implementation method, the calculation method of the outer boundary deformation of the fiberglass layer is as follows: Based on the thick-walled cylinder theory, obtain the displacement expression of the fiberglass layer under the action of the full reservoir working pressure; according to the outer boundary radius of the fiberglass layer and the displacement expression, obtain the outer boundary deformation of the fiberglass layer under the action of the full reservoir working pressure.

[0011] As a further implementation method, for the fiberglass layer and the reinforced concrete layer, take the initial inflation stage as the initial state; according to the theory of elasticity, calculate the stress and displacement of the fiberglass layer and the reinforced concrete layer respectively, and calculate the radial elastic displacement of the surrounding rock layer. According to the continuity of the radial stress at the inner and outer boundaries of the fiberglass layer, the inner and outer boundaries of the reinforced concrete layer and the inner side of the surrounding rock layer and the equality of the boundary displacement, obtain the contact stress between the surrounding rock and the reinforced concrete layer.

[0012] As a further implementation method, calculate the maximum circumferential stress of the fiberglass layer and the reinforced concrete layer through the stress equation, and use the safety factor method to judge whether the fiberglass layer and the reinforced concrete layer are damaged.

[0013] As a further implementation method, when the FRP layer or reinforced concrete layer is damaged or does not meet the set safety factor, the material and thickness of the FRP layer or reinforced concrete layer are modified, and the calculation process of the empty reservoir stage, the initial inflation stage, the later inflation stage and the full reservoir operation stage is repeated.

[0014] The beneficial effects of the present invention are as follows: (1) The composite toughness sealing lining structure of the present invention is composed of a glass fiber reinforced plastic layer, a flexible cushion layer, and a reinforced concrete layer. The flexible cushion layer is closely attached to the inner side of the reinforced concrete layer, leaving deformation space for the glass fiber reinforced plastic layer; the glass fiber reinforced plastic layer is closely attached to the inner side of the flexible cushion layer, playing the role of sealing high-pressure air and bearing the internal pressure of the reservoir; when subjected to high internal pressure, the composite toughness sealing lining structure works in coordination with the surrounding rock, the glass fiber reinforced plastic layer bears part of the internal pressure to ensure good sealing of the reservoir, the flexible cushion layer can reduce the friction contact between the glass fiber reinforced plastic layer and the reinforced concrete layer, and cope with the problem of uncoordinated deformation of different materials, the reinforced concrete layer transfers the load to the surrounding rock, the structure deforms in a coordinated manner, and the surrounding rock bears the main internal pressure, which can give full play to the surrounding rock's own bearing capacity and is suitable for soft / hard surrounding rock.

[0015] (2) The present invention is divided into the following stages according to the stress conditions of the compressed air energy storage reservoir and the working characteristics of the composite toughness sealing lining structure: the first stage: the empty reservoir stage, it is defined that the surrounding rock pressure and water pressure are all borne by the reinforced concrete layer structure, the surrounding rock pressure and water pressure, the internal pressure of the reinforced concrete layer are calculated, and the cross-section design is performed; the second stage, the initial stage of the inflation stage, it is defined that the flexible cushion layer does not bear any load, the FRP layer and the reinforced concrete layer are emptied, and the inflation pressure in this process is all borne by the FRP layer, the thickness of the flexible cushion layer is taken as the radial deformation of the FRP layer, and the inflation pressure and the internal pressure of the FRP layer are calculated; in the late inflation stage and the full reservoir operation stage, it is defined that the FRP layer and the reinforced concrete layer are tightly fitted, and they share the internal gas pressure of the reservoir with the surrounding rock, the full reservoir working pressure is taken as the calculation load, the stress of the FRP layer, the reinforced concrete layer and the surrounding rock is calculated, and the cross-section design is performed considering the appropriate safety factor; it can reflect the stress distribution of each structure of the compressed air energy storage reservoir, thereby quickly determining the material and thickness selection of each structure, and saving the cost of the underground gas storage cavern. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0017] Figure 1 is a schematic diagram of a composite toughness sealing lining structure according to one or more embodiments of the present invention; Figure 2 The present invention is a calculation diagram of reinforced concrete layer load and internal pressure in the empty warehouse stage according to one or more embodiments. Figure 3 is the load and internal pressure calculation diagram of the fiberglass layer at the initial stage of the inflation phase according to one or more embodiments of the present invention; Figure 4 is the calculation diagram of the collaborative action between the sealed lining structure and the surrounding rock in the later stage of the inflation phase and the full reservoir phase according to one or more embodiments of the present invention; Figure 5 is the flowchart of the design method according to one or more embodiments of the present invention.

[0018] Among them, 1. surrounding rock, 2. reinforced concrete layer, 3. flexible cushion layer, 4. fiberglass layer. Specific embodiments It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0019] Example 1: This embodiment provides a composite tough sealed lining structure for a compressed air energy storage reservoir, combined with Figure 1 as shown, including a reinforced concrete layer 2, a flexible cushion layer 3, and a fiberglass layer 4. The reinforced concrete layer 2 is arranged inside the surrounding rock 1 and is a composite lining composed of primary support and secondary lining. Its main function is to level the tunnel wall and bear the pressure of the surrounding rock and water pressure; the flexible cushion layer 3 is arranged closely inside the reinforced concrete layer 2, mainly to reserve a deformation space for the fiberglass layer 4; the fiberglass layer 4 is an integral structure and is arranged closely inside the flexible cushion layer 3. Its main function is to seal high-pressure air and bear the internal pressure of the reservoir.

[0020] In this embodiment, the cross-sections of the reinforced concrete layer 2, the flexible cushion layer 3, and the fiberglass layer 4 are circular; the flexible cushion layer 3 can be made of rubber material. The elastic modulus of the reinforced concrete layer 2 is close to the elastic modulus of the surrounding rock 1, and its strength is higher than that of the surrounding rock 1; the elastic modulus of the flexible cushion layer 3 is much smaller than the elastic modulus of the surrounding rock 1.

[0021] The composite toughness sealing lining structure of this embodiment consists of a reinforced concrete layer 2, a flexible cushion layer 3 and a glass fiber reinforced plastic layer 4. The flexible cushion layer 3 is tightly attached to the inner side of the reinforced concrete layer 2, reserving deformation space for the glass fiber reinforced plastic layer 4; the glass fiber reinforced plastic layer 4 is tightly attached to the inner side of the flexible cushion layer 3, sealing the high-pressure air and bearing the internal pressure of the reservoir; when subjected to high internal pressure, the composite toughness sealing lining structure works in coordination with the surrounding rock 1, and the glass fiber reinforced plastic layer 4 bears part of the internal pressure to ensure good sealing of the reservoir. The flexible cushion layer 3 can reduce the friction contact between the glass fiber reinforced plastic layer 4 and the reinforced concrete layer 2, and cope with the problem of uncoordinated deformation of different materials. The reinforced concrete layer 2 transfers the load to the surrounding rock 1, and the structure deforms in a coordinated manner. The surrounding rock 1 bears the main internal pressure, which can give full play to the bearing capacity of the surrounding rock 1 itself, and is suitable for soft / hard surrounding rocks.

[0022] Embodiment 2: This embodiment provides a design method for a composite toughness sealing lining structure of a compressed air energy storage reservoir. Figure 5 As shown, the following steps are included: S1. In the empty reservoir stage, the surrounding rock pressure and water pressure are all borne by the reinforced concrete layer structure. Through field tests and indoor tests, the surrounding rock mechanical parameters are determined, the surrounding rock groundwater activity is obtained, the surrounding rock pressure and water pressure are calculated, and the reinforced concrete layer is preliminarily set.

[0023] Furthermore, S1.1, the surrounding rock pressure acting on the reinforced concrete layer is calculated, wherein the surrounding rock pressure includes vertical surrounding rock pressure and horizontal surrounding rock pressure.

[0024] Select the site of the underground gas storage cavern and determine the surrounding rock mechanical parameters, including the elastic modulus, based on the test. , Poisson's ratio etc., to determine the surrounding rock grade; at a given cavern burial depth , Gas storage scale , Full warehouse working pressure , Excavation radius Then, the vertical surrounding rock pressure was calculated by referring to the "TB10003-2016 Railway Tunnel Design Code" Horizontal surrounding rock pressure .

[0025] S1.2. Calculate the water pressure acting on the reinforced concrete layer: Combination Figure 2 As shown in the figure, based on geological data and field tests, the effective water head from the groundwater level to the center of the cavern is obtained. , taking water pressure as the surface force acting on the outer boundary of the reinforced concrete layer, the water pressure is calculated by referring to the "SL279-2016 Hydraulic Tunnel Design Code" .

[0026] S1.3. Design the reinforced concrete layer: Refer to the "Code for Design of Concrete Structures" (GB50010-2010) and the "Code for Design of Hydraulic Tunnels" (SL279-2016) to determine the elastic modulus, Poisson's ratio and thickness of the concrete, and determine the elastic modulus, Poisson's ratio and area of the reinforcement, and complete the cross-section design of the reinforced concrete layer.

[0027] S2. For the initial inflation stage, preliminarily set the type and thickness of the fiberglass reinforced plastic. Assuming that the flexible cushion does not bear the load, the fiberglass reinforced plastic layer is separated from the reinforced concrete layer, and the inflation pressure is entirely borne by the fiberglass reinforced plastic layer. Taking the thickness of the flexible cushion as the radial deformation of the fiberglass reinforced plastic layer, calculate the initial inflation pressure and the internal pressure of the fiberglass reinforced plastic layer.

[0028] Furthermore, S2.1. Calculate the deformation of the outer boundary of the fiberglass reinforced plastic layer when it bears the full reservoir working pressure: Combined with the material properties of the fiberglass reinforced plastic, preliminarily determine the elastic modulus , Poisson's ratio and strength parameters of the fiberglass reinforced plastic layer, and preliminarily set the type of fiberglass reinforced plastic, the inner boundary radius and outer boundary radius of the fiberglass reinforced plastic layer.

[0029] Based on the thick-walled cylinder theory, obtain the displacement of the fiberglass reinforced plastic layer under the action of the full reservoir working pressure : (1) In formula (1), is the displacement of each point of the fiberglass reinforced plastic layer, is the inner boundary radius of the fiberglass reinforced plastic layer, is the outer boundary radius of the fiberglass reinforced plastic layer, is the distance from any point inside the fiberglass reinforced plastic layer to the center of the tunnel.

[0030] Substitute the outer boundary radius of the fiberglass reinforced plastic layer into formula (1), and the deformation of the outer boundary of the fiberglass reinforced plastic layer under the action of the full reservoir working pressure can be obtained as: (2) In formula (2), is the deformation of the outer boundary of the fiberglass reinforced plastic layer.

[0031] S2.2. Preliminarily set the thickness of the flexible cushion: Since the elastic modulus of the flexible cushion is much smaller than that of the fiberglass reinforced plastic layer, the force on the flexible cushion can be ignored. Taking the thickness of the flexible cushion as the reference for the deformation of the outer boundary of the fiberglass reinforced plastic layer, preliminarily set the thickness of the flexible cushion as b, and it is considered that the flexible cushion is in direct contact with the reinforced concrete layer in the subsequent calculations.

[0032] S2.3. Calculate the internal pressure of the fiberglass reinforced plastic layer: Combined withFigure 3 As shown, based on the numerical equality of the flexible cushion thickness and the deformation amount of the outer boundary of the FRP layer, calculate the internal pressure borne by the FRP layer under this setting: (3) In Equation (3), is the internal pressure borne by the FRP layer under the current setting.

[0033] S3. For the late inflation stage and the full - reservoir operation stage, based on the close fit between the FRP layer and the reinforced concrete layer and their joint bearing of the internal gas pressure of the reservoir, taking the full - reservoir working pressure as the calculation load, calculate the forces on the FRP layer, the reinforced concrete layer, and the surrounding rock, and determine whether the FRP layer and the reinforced concrete layer are damaged. If no damage occurs, it indicates that the corresponding structural design is reasonable; if damage occurs, the materials and thickness of the corresponding structure need to be changed, and repeat steps S1 - S3 until the requirements are met.

[0034] S3.1. Calculate the inner - boundary radius and outer - boundary radius of the FRP layer at the initial state in the late inflation stage: Based on the internal pressure borne by the FRP layer calculated in step S2 as the initial state in the late inflation stage, the calculation formula for the deformation amount of the inner boundary of the FRP layer is: (4) In Equation (4), is the deformation amount of the inner boundary of the FRP layer.

[0035] The inner - boundary radius of the FRP layer at the initial state in the late inflation stage is: (5) The outer - boundary radius of the FRP layer at the initial state in the late inflation stage is: (6) S3.2. Calculate the stress and displacement distributions of each structure in the late inflation stage and the full - reservoir operation stage: For the FRP layer and the reinforced concrete layer, taking the initial inflation stage as the initial state, there is an air - internal - pressure increment of in the full - reservoir operation stage, which is shared by the FRP layer, the flexible cushion, the reinforced concrete layer, and the surrounding rock; according to the theory of elasticity, the stresses and displacements of the FRP layer and the reinforced concrete layer at this time are respectively: (7) (8) (9) (10) (11) (12) In the above formula, j = 0 represents the fiberglass layer, and j = 1 represents the reinforced concrete layer; is the radial stress of the fiberglass layer caused under the full reservoir working pressure ; is the radial stress of the reinforced concrete layer caused under the full reservoir working pressure ; is the circumferential stress of the fiberglass layer caused under the full reservoir working pressure ; is the circumferential stress of the reinforced concrete layer caused under the full reservoir working pressure ; is the radial displacement of the fiberglass layer caused under the full reservoir working pressure ; is the radial displacement of the reinforced concrete layer caused under the full reservoir working pressure ; and are undetermined constants, and are undetermined constants of the fiberglass layer, and are undetermined constants of the reinforced concrete layer; is the Poisson's ratio of the fiberglass layer, is the Poisson's ratio of the reinforced concrete layer; is the elastic modulus of the fiberglass layer, is the elastic modulus of the reinforced concrete layer; is the distance from any point inside the fiberglass layer to the center of the cavern; is the distance from any point inside the reinforced concrete layer to the center of the cavern.

[0036] The radial elastic displacement of the surrounding rock layer is: (13) In formula (13), is the radial displacement of the surrounding rock, is the contact stress between the surrounding rock layer and the reinforced concrete layer.

[0037] Combined with Figure 4 shown, according to the continuity of the radial stress and the equality of the boundary displacement amounts at the inner and outer boundaries of the fiberglass layer, the inner and outer boundaries of the reinforced concrete layer, and the inner side of the surrounding rock layer, the calculation formula can be obtained: (14) (15) (16) (17) (18) By substituting the known parameters, the undetermined constants can be obtained and the contact stress between the surrounding rock layer and the reinforced concrete layer .

[0038] S3.3 Calculate whether the fiberglass layer and the reinforced concrete layer are damaged: The stresses of each structure can be calculated through the stress equations corresponding to the fiberglass layer and the reinforced concrete layer. The safety factor method is used to judge whether the fiberglass layer and the reinforced concrete layer are damaged. Then, the fiberglass layer and the reinforced concrete layer should meet the following conditions: (19) (20) In the formula, is the ultimate tensile strength of the fiberglass layer, is the maximum circumferential stress of the fiberglass layer; is the circumferential tension of the reinforced concrete layer, is the design value of the tensile strength of the reinforcement; is the cross-sectional area of the reinforcement; n is the safety factor, which is selected according to the specific project.

[0039] According to the stress conditions of the compressed air energy storage reservoir and the working characteristics of the composite tough sealing lining structure, the design method of this embodiment is as follows: In the first stage, the empty reservoir stage, it is defined that the surrounding rock pressure and water pressure are all borne by the reinforced concrete layer structure, and the surrounding rock pressure, water pressure, and internal pressure of the reinforced concrete layer are calculated, and the cross-section design is carried out. In the second stage, at the initial stage of the inflation stage, it is defined that the flexible cushion does not bear the load, and the fiberglass layer and the reinforced concrete layer are separated. During this process, the inflation pressure is all borne by the fiberglass layer. Taking the thickness of the flexible cushion as the radial deformation of the fiberglass layer, the inflation pressure and the internal pressure of the fiberglass layer are calculated; in the later stage of the inflation stage and the full reservoir operation stage, it is defined that the fiberglass layer and the reinforced concrete layer are closely attached and jointly bear the internal gas pressure of the reservoir with the surrounding rock. Taking the full reservoir working pressure of the reservoir as the calculation load, the stresses of the fiberglass layer (using the result of step S1 as the initial state of the fiberglass layer in this stage), the reinforced concrete layer, and the surrounding rock are calculated, and the cross-section design is carried out considering an appropriate safety factor; it can reflect the stress distribution of each structure of the compressed air energy storage reservoir, so as to quickly determine the selection of materials and thickness of each structure and save the cost of underground gas storage caverns.

[0040] Example 3: According to the design method described in Example 2, for a certain under-construction compressed air energy storage reservoir, the specific process includes: Step S1: For a certain anhydrite mining area, the elastic modulus of the surrounding rock is determined through on-site investigation = 32.61 GPa, Poisson's ratio = 0.15. According to the engineering requirements, the buried depth of the cavern is given = 89 m, the cross-section of the storage is circular, with a length of 100 m, and the gas storage scale is not less than 5000 m 3 , and the working pressure when the storage is full = 10 MPa, the excavation radius = 5 m.

[0041] From the geological data, it can be known that the BQ here is 658.71, and the unit weight of the rock mass is 29.40 KN / m 3 , referring to the "Code for Design of Railway Tunnels TB10003 - 2016", it is determined as a deep-buried project. According to the classification of tunnel surrounding rock grades, the surrounding rock grade is Class Ⅰ, and the vertical surrounding rock pressure under the given burial depth is obtained = 2.78 MPa.

[0042] The horizontal surrounding rock pressure depends on the vertical surrounding rock pressure and the surrounding rock grade, and is obtained by referring to Table 1 according to experience.

[0043] Table 1 Reference Table of Horizontal Surrounding Rock Pressure for Deep-Buried Caverns

[0044] After referring to Table 1, it is obtained that = 0.

[0045] After investigation, the acting water head from the groundwater level line to the center of the cavern is obtained as 13 m.

[0046] According to the surrounding rock information and the groundwater activity situation, referring to the "Code for Design of Hydraulic Tunnel SL279 - 2016", the reduction coefficient β is obtained e = 0.2, and the water pressure P is obtained by using the reduction coefficient method w = 26 kPa.

[0047] Table 2 Reduction Coefficient β of Water Pressure e Table

[0048] According to the surrounding rock pressure and water pressure received, considering the action of the working pressure when the storage is full, referring to the "Code for Design of Concrete Structures GB50010 - 2010" and the "Code for Design of Hydraulic Tunnel SL279 - 2016", a double-layer reinforced concrete lining is set. The steel bars are selected as HRB400, with a Poisson's ratio of 0.3 and an elastic modulus of 200 GPa. The concrete is selected as C40, with an elastic modulus of 32.5 GPa, a compressive strength of 19.1 MPa, a tensile strength of 1.71 MPa, and a Poisson's ratio of 0.167. The thickness of the concrete is set as 0.4 m, and the inner diameter is 4.6 m. The reinforcement is set by calculating according to the boundary value method.

[0049] Step S2: Query relevant cases and preliminarily determine to use epoxy resin fiberglass as the fiberglass layer material, with an elastic modulus of 10GPa, a Poisson's ratio of 0.25, and a tensile strength of 320MPa. The fiberglass layer thickness is preliminarily set to 0.15m and the inner diameter is 4.4m.

[0050] The deformation of the FRP layer when it bears the full warehouse working pressure is calculated. According to formula (2), the deformation of the outer boundary is 0.14m. Since the surrounding rock is in good condition, the internal pressure borne by the FRP layer is taken as 30% of the full warehouse pressure. The thickness of the rubber cushion layer is initially set to b=0.05m, and the gap between the reinforced concrete layer and the reinforced concrete layer is filled with concrete. According to b=0.05m, substitute it into formula (2) to calculate the internal pressure borne by the FRP layer at this time, q0=2.274 MPa.

[0051] Step S3: The internal pressure of the FRP layer calculated in step S2 is taken as the initial state of the later stage of inflation. The deformation of the inner boundary of the FRP layer is calculated by formula (3) as follows: =0.05m. The initial state of the FRP layer in the late inflation stage and the full storage operation stage is calculated by formula (4)-(5), and the known parameters are substituted into formula (14)-(18) to obtain the corresponding unknown constants and contact stresses. The stress and displacement of each structure in the late inflation stage and the operation stage can be obtained by formula (7)-(13). Superimposed on the force of the FRP layer in the early inflation stage, the load proportion of each structure can be calculated based on the obtained radial stress. The FRP layer bears an internal pressure of 3.796MPa, accounting for about 38%, the reinforced concrete layer bears an internal pressure of 0.944MPa, accounting for about 9%, and the surrounding rock bears an internal pressure of 5.258MPa, accounting for about 53%.

[0052] In this embodiment, the safety factor n is 2, the maximum hoop stress of the FRP layer is 108 MPa, and the hoop tension of the reinforced concrete layer is about 4496.86 kN. It can be calculated by formulas (19)-(20) that the structure is within the safety range and meets the design requirements.

[0053] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A composite ductile sealing lining structure for a compressed air energy storage reservoir, characterized in that It includes a reinforced concrete layer, a flexible cushion layer, and a fiberglass layer arranged in sequence from outside to inside. The reinforced concrete layer is set according to the surrounding rock pressure and water pressure. The fiberglass layer is used to seal high-pressure air and bear the internal pressure of the storage. The flexible cushion layer is used to reserve the deformation space for the fiberglass layer, so that the formed composite tough sealing lining structure can cooperate with the surrounding rock to bear force.

2. The composite tough sealing lining structure of a compressed air energy storage reservoir according to claim 1, characterized in that, The cross-sections of the reinforced concrete layer, the flexible cushion layer, and the fiberglass layer are circular.

3. A composite ductile sealing lining structure for a compressed air energy storage reservoir according to claim 1 or 2, characterized in that, The elastic modulus of the reinforced concrete layer does not exceed that of the surrounding rock, and the elastic modulus of the flexible cushion layer is less than that of the surrounding rock.

4. The design method of a composite tough sealing lining structure for a compressed air energy storage reservoir, according to any one of claims 1-3, is characterized in that It includes: In the empty-storage stage of the storage, based on the fact that the surrounding rock pressure and water pressure are all borne by the reinforced concrete layer, calculate the surrounding rock pressure and water pressure, and set the reinforced concrete layer accordingly; In the initial inflation stage, based on the fact that the initial inflation pressure is all borne by the fiberglass layer, and taking the thickness of the flexible cushion layer as the radial deformation amount of the fiberglass layer, calculate the initial inflation pressure and the internal pressure of the fiberglass layer; In the later inflation stage and the full-storage operation stage, taking the increment of the full-storage working pressure of the storage relative to the initial inflation pressure as the calculated load, calculate the forces borne by the fiberglass layer, the reinforced concrete layer, and the surrounding rock, and judge whether damage occurs based on the forces borne by the fiberglass layer and the reinforced concrete layer; when the fiberglass layer and the reinforced concrete layer do not suffer damage and meet the set safety factor, obtain a sealing lining structure that meets the design requirements.

5. The design method of a composite ductile sealing lining structure for a compressed air energy storage reservoir according to claim 4, characterized in that The calculation method of the surrounding rock pressure is: First, determine the mechanical parameters of the surrounding rock, judge the surrounding rock grade, set the buried depth of the cavern, the gas storage scale, the full-storage working pressure, and the excavation radius, and calculate the vertical surrounding rock pressure and the horizontal surrounding rock pressure; The calculation method of the water pressure is: Obtain the acting water head from the groundwater level line to the center of the cavern, and take the water pressure as the surface force acting on the outer boundary of the reinforced concrete layer to calculate the water pressure.

6. The design method of a composite ductile sealing lining structure for a compressed air energy storage reservoir according to claim 4, characterized in that, Calculate the outer boundary deformation amount of the fiberglass layer when it bears the full-storage working pressure; According to the fact that the thickness of the flexible cushion layer is equal to the outer boundary deformation amount of the fiberglass layer, calculate the internal pressure borne by the fiberglass layer.

7. The design method of a composite tough sealing lining structure for a compressed air energy storage reservoir according to claim 6, characterized in that, The calculation method of the outer boundary deformation amount of the fiberglass layer is: Based on the thick-walled cylinder theory, obtain the displacement expression of the fiberglass layer under the action of the full-storage working pressure; according to the outer boundary radius of the fiberglass layer and the displacement expression, obtain the outer boundary deformation amount of the fiberglass layer under the action of the full-storage working pressure.

8. The design method of a composite tough sealing lining structure for a compressed air energy storage reservoir according to claim 4, characterized in that, For the fiberglass layer and the reinforced concrete layer, take the initial inflation stage as the initial state; according to the theory of elasticity, calculate the stress and displacement of the fiberglass layer and the reinforced concrete layer respectively, and calculate the radial elastic displacement of the surrounding rock layer; According to the radial stress continuity and the equal boundary displacement amount of the inner and outer boundaries of the fiberglass layer, the inner and outer boundaries of the reinforced concrete layer, and the inner side of the surrounding rock layer, obtain the contact stress between the surrounding rock and the reinforced concrete layer.

9. The design method of a composite ductile sealing lining structure for a compressed air energy storage reservoir according to claim 4, characterized in that, Calculate the maximum circumferential stress of the fiberglass layer and the reinforced concrete layer through the stress equation, and use the safety factor method to judge whether the fiberglass layer and the reinforced concrete layer are damaged.

10. The design method of a composite tough sealing lining structure for a compressed air energy storage reservoir according to claim 4, characterized in that, When the fiberglass layer or the reinforced concrete layer is damaged or does not meet the set safety factor, modify the materials and thickness of the fiberglass layer or the reinforced concrete layer, and repeat the calculation process of the empty-storage stage, the initial inflation stage, the later inflation stage, and the full-storage operation stage of the storage.

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