A composite toughness sealing lining structure and method for compressed air energy storage

Abstract

The present invention discloses a composite toughness sealing lining structure and method for a compressed air energy storage reservoir, relating to the technical field of compressed air energy storage, wherein the sealing lining structure comprises a reinforced concrete layer, a flexible cushion layer and a fiberglass reinforced plastic layer arranged in sequence from the outside to the inside, the reinforced concrete layer being arranged according to the surrounding rock pressure and the water pressure, the fiberglass reinforced plastic layer being used to seal the high-pressure air and bear the internal pressure of the reservoir, and the flexible cushion layer being used to reserve deformation space for the fiberglass reinforced plastic layer, so that the formed composite toughness sealing lining structure can cooperate with the surrounding rock to bear force, thereby ensuring good sealing of the reservoir and being able to give full play to the surrounding rock's own bearing capacity.

Description

Technical Field

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

[0002] Compressed air energy storage facilities seal and store high-pressure gas through the coordinated forces of a sealed lining structure and surrounding rock, ensuring good stability. Current gas storage sealing structures primarily rely on steel plate sealing, consisting of a steel lining and concrete lining, which effectively reduces permeability. However, this structure has drawbacks. When the surrounding rock of the gas storage facility is soft, the modulus of the steel is much greater than that of the surrounding rock. The sealing structure bears the majority of the compressed air pressure, failing to fully utilize the bearing capacity of the surrounding rock. Stress concentration easily occurs at the contact point between the steel lining and the surrounding rock, making the sealing layer more susceptible to damage and ultimately seal failure, impacting the long-term stability of the gas storage facility. Furthermore, the direct contact between the concrete lining and the steel lining creates significant friction and tangential forces. This can lead to degradation of the concrete lining's performance during long-term high and low temperature cycles, storage and release, and loading and unloading, resulting in cracks and spalling, impacting its structural safety and airtightness. Summary of the Invention

[0003] In view of the shortcomings 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 cooperate with the surrounding rock to bear force, ensure good sealing of the reservoir, and fully utilize the bearing capacity of the surrounding rock itself.

[0004] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0005] In the first aspect, an embodiment of the present invention provides a composite toughness sealed lining structure for a compressed air energy storage reservoir, comprising a reinforced concrete layer, a flexible cushion layer and a fiberglass layer arranged in sequence from the outside to the inside, wherein the reinforced concrete layer is arranged according to the surrounding rock pressure and the water pressure, the fiberglass layer is used to seal the high-pressure air and bear the internal pressure of the reservoir, and the flexible cushion layer is used to reserve deformation space for the fiberglass layer.

[0006] As a further implementation, the cross-sections of the reinforced concrete layer, the flexible cushion layer and the fiberglass reinforced plastic layer are circular.

[0007] As a further implementation, 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 smaller than the elastic modulus of the surrounding rock.

[0008] In a second aspect, an embodiment of the present invention further provides a method for designing a composite toughness sealing lining structure of a compressed air energy storage reservoir, comprising:

[0009] During the empty reservoir stage, the surrounding rock pressure and water pressure are calculated based on the assumption that they are all borne by the reinforced concrete layer, and the reinforced concrete layer is set accordingly.

[0010] At the initial inflation stage, the initial inflation pressure and the internal pressure of the FRP layer are calculated based on the assumption that the initial inflation pressure is entirely borne by the FRP layer and the thickness of the flexible cushion layer is taken as the radial deformation of the FRP layer;

[0011] In the late stage of inflation and full-storage operation, the increment of the full-storage working pressure relative to the initial inflation pressure is used as the calculation load to calculate the stress on the FRP layer, reinforced concrete layer and surrounding rock, and whether damage occurs is determined based on the stress. When the FRP layer and reinforced concrete layer are not damaged and meet the set safety factor, a sealed lining structure that meets the design requirements is obtained.

[0012] As a further implementation method, the surrounding rock pressure is calculated as follows:

[0013] First, determine the surrounding rock mechanical parameters, judge the surrounding rock grade, set the cavern burial depth, gas storage capacity, full storage working pressure, excavation radius, and calculate the vertical and horizontal surrounding rock pressures;

[0014] The water pressure is calculated as follows:

[0015] Obtain the acting water head from the groundwater level to the center of the cavern, and calculate the water pressure by taking the water pressure as the surface force acting on the outer boundary of the reinforced concrete layer.

[0016] As a further implementation method, the outer boundary deformation of the FRP layer when subjected to full warehouse working pressure is calculated;

[0017] Based on the fact that the thickness of the flexible cushion layer is equal to the deformation of the outer boundary of the FRP layer, the internal pressure borne by the FRP layer is calculated.

[0018] As a further implementation method, the calculation method of the outer boundary deformation of the fiberglass reinforced plastic layer is:

[0019] Based on the thick-walled cylinder theory, the displacement expression of the FRP layer under full storage working pressure is obtained; according to the outer boundary radius of the FRP layer and the displacement expression, the outer boundary deformation of the FRP layer under full storage working pressure is obtained.

[0020] As a further implementation method, for the FRP layer and reinforced concrete layer, the initial state is taken as the initial state; according to the theory of elastic mechanics, the stress and displacement of the FRP layer and reinforced concrete layer are calculated respectively, and the radial elastic displacement of the surrounding rock layer is calculated;

[0021] According to the continuity of radial stress and the equality of boundary displacement between the inner and outer boundaries of the FRP layer, the inner and outer boundaries of the reinforced concrete layer and the inner side of the surrounding rock layer, the contact stress between the surrounding rock and reinforced concrete layer is obtained.

[0022] As a further implementation method, the maximum hoop stress of the FRP layer and the reinforced concrete layer is calculated by the stress equation, and the safety factor method is used to determine whether the FRP layer and the reinforced concrete layer are damaged.

[0023] 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 late inflation stage and the full reservoir operation stage is repeated.

[0024] The beneficial effects of the present invention are as follows:

[0025] (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, ensuring 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 deal 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.

[0026] (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 carried out; the second stage, the initial stage of the inflation stage, it is defined that the flexible cushion layer does not bear the load, the FRP layer and the reinforced concrete layer are empty, 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, reinforced concrete layer and surrounding rock is calculated, and the cross-section design is carried out 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, saving the cost of underground gas storage caverns. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings, 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.

[0028] Figure 1 is a schematic diagram of a composite toughness sealing lining structure according to one or more embodiments of the present invention;

[0029] Figure 2 The load and internal pressure calculation diagram of reinforced concrete layer in empty warehouse stage according to one or more embodiments of the present invention is shown in FIG.

[0030] Figure 3 is a calculation diagram of the load and internal pressure of the FRP layer during the initial inflation phase according to one or more embodiments of the present invention;

[0031] Figure 4 is a calculation diagram of the synergistic effect between the sealing lining structure and the surrounding rock in the late stage of the inflation phase and the full reservoir phase according to one or more embodiments of the present invention;

[0032] Figure 5 is a flow chart of a design method according to one or more embodiments of the present invention.

[0033] Among them, 1. surrounding rock, 2. reinforced concrete layer, 3. flexible cushion layer, 4. fiberglass layer. DETAILED DESCRIPTION

[0034] 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 skilled in the art to which the present invention belongs.

[0035] Example 1:

[0036] This embodiment provides a composite toughness sealing lining structure for a compressed air energy storage tank. Figure 1 As shown, it includes a reinforced concrete layer 2, a flexible cushion layer 3 and a glass fiber reinforced plastic layer 4. The reinforced concrete layer 2 is arranged on the inner side of the surrounding rock 1. It is a composite lining composed of initial support and secondary lining. Its main function is to level the cave wall and bear the surrounding rock pressure and water pressure. The flexible cushion layer 3 is arranged closely on the inner side of the reinforced concrete layer 2, mainly to reserve deformation space for the glass fiber reinforced plastic layer 4. The glass fiber reinforced plastic layer 4 is an integrated structure, which is arranged closely on the inner side of the flexible cushion layer 3. Its main function is to seal the high-pressure air and bear the internal pressure of the reservoir.

[0037] In this embodiment, the reinforced concrete layer 2, flexible cushion layer 3, and fiberglass reinforced plastic layer 4 have circular cross-sections; the flexible cushion layer 3 can be made of rubber. The elastic modulus of the reinforced concrete layer 2 is close to that 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 lower than that of the surrounding rock 1.

[0038] This embodiment comprises a composite toughness sealing lining structure consisting 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 frictional contact between the glass fiber reinforced plastic layer 4 and the reinforced concrete layer 2, and address 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.

[0039] Example 2:

[0040] 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:

[0041] 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.

[0042] Furthermore, S1.1, calculate the surrounding rock pressure acting on the reinforced concrete layer, where the surrounding rock pressure includes vertical surrounding rock pressure and horizontal surrounding rock pressure.

[0043] 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., judge the surrounding rock grade; in 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" and horizontal surrounding rock pressure .

[0044] S1.2. Calculate the water pressure acting on the reinforced concrete layer:

[0045] Combine 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 with reference to the "SL279-2016 Hydraulic Tunnel Design Code" .

[0046] S1.3 Design of reinforced concrete layer:

[0047] With reference to GB50010-2010 Code for Design of Concrete Structures and SL279-2016 Code for Design of Hydraulic Tunnels, the elastic modulus, Poisson's ratio, and thickness of concrete, as well as the elastic modulus, Poisson's ratio, and area of ​​reinforcement, were determined to complete the cross-sectional design of the reinforced concrete layer.

[0048] S2. For the initial stage of inflation, the type and thickness of FRP are preliminarily set. Assuming that the flexible cushion layer does not bear any load, the FRP layer and the reinforced concrete layer are separated, and the inflation pressure is entirely borne by the FRP layer, the thickness of the flexible cushion layer is used as the radial deformation of the FRP layer, and the initial inflation pressure and the internal pressure of the FRP layer are calculated.

[0049] Furthermore, S2.1, calculate the deformation of the outer boundary of the FRP layer when it is subjected to full warehouse working pressure:

[0050] Combined with the characteristics of FRP materials, the elastic modulus of the FRP layer is preliminarily determined , Poisson's ratio and strength parameters, preliminarily set the type of FRP, the inner boundary radius of the FRP layer With outer border radius .

[0051] Based on the thick-walled cylinder theory, the working pressure in the full tank is obtained Displacement of the FRP layer under action:

[0052] (1)

[0053] In formula (1), is the displacement of each point in the FRP layer, is the inner boundary radius of the FRP layer, is the outer boundary radius of the FRP layer, It is the distance from any point in the FRP layer to the center of the cavern.

[0054] Substituting the outer boundary radius of the FRP layer into formula (1), the outer boundary deformation of the FRP layer under full warehouse working pressure can be obtained as:

[0055] (2)

[0056] In formula (2), is the outer boundary deformation of the FRP layer.

[0057] S2.2. Preliminary setting of thickness of flexible cushion layer:

[0058] Since the elastic modulus of the flexible cushion layer is much smaller than that of the FRP layer, the force on the flexible cushion layer can be ignored. Taking the thickness of the flexible cushion layer as a reference for the deformation of the outer boundary of the FRP layer, the thickness of the flexible cushion layer is initially set to b. In subsequent calculations, it is assumed that the flexible cushion layer is in direct contact with the reinforced concrete layer.

[0059] S2.3. Calculate the internal pressure of the FRP layer:

[0060] Combine Figure 3 As shown in the figure, based on the fact that the thickness of the flexible cushion layer is equal to the deformation of the outer boundary of the FRP layer, the internal pressure borne by the FRP layer under this setting is calculated:

[0061] (3)

[0062] In formula (3), is the internal pressure that the FRP layer is subjected to under the current settings.

[0063] S3. For the late inflation stage and full storage operation stage, based on the fact that the FRP layer fits tightly with the reinforced concrete layer and shares the internal gas pressure of the reservoir with the surrounding rock, the full storage working pressure is used as the calculation load to calculate the forces on the FRP layer, reinforced concrete layer and surrounding rock, and determine whether the FRP layer and reinforced concrete layer are damaged. If no damage occurs, it indicates that the corresponding structural design is reasonable; if damage occurs, the material and thickness of the corresponding structure need to be changed, and steps S1 to S3 are repeated until the requirements are met.

[0064] S3.1. Calculate the inner and outer boundary radii of the FRP layer at the initial state of the late inflation period:

[0065] The internal pressure of the FRP layer calculated in step S2 is used as the initial state of the later inflation period. The calculation formula for the deformation of the inner boundary of the FRP layer is:

[0066] (4)

[0067] In formula (4), is the deformation of the inner boundary of the FRP layer.

[0068] The inner boundary radius of the FRP layer at the initial state of the late inflation period is:

[0069] (5)

[0070] The outer boundary radius of the FRP layer at the initial state of the late inflation period is:

[0071] (6)

[0072] S3.2. Calculate the stress and displacement distribution of each structure in the late stage of inflation and full storage operation:

[0073] For the glass fiber reinforced plastic layer and reinforced concrete layer, the initial state is the initial state, and there is The increase in air internal pressure is shared by the FRP layer, flexible cushion layer, reinforced concrete layer and surrounding rock. According to the theory of elastic mechanics, the stress and displacement of the FRP layer and reinforced concrete layer are:

[0074] (7)

[0075] (8)

[0076] (9)

[0077] (10)

[0078] (11)

[0079] (12)

[0080] In the above formula, j=0 represents the fiberglass layer, and j=1 represents the reinforced concrete layer; Working under full warehouse pressure The radial stress of the FRP layer caused by Working under full warehouse pressure The radial stress of reinforced concrete layer caused by Working under full warehouse pressure The hoop stress of the FRP layer caused by Working under full warehouse pressure The hoop stress in the reinforced concrete layer is caused by Working under full warehouse pressure The radial displacement of the FRP layer caused by Working under full warehouse pressure Radial displacement of reinforced concrete layer caused by and is an undetermined constant, and is the undetermined constant of the FRP layer, and is the undetermined constant of the reinforced concrete layer; is the Poisson's ratio of the FRP layer, is the Poisson's ratio of the reinforced concrete layer; is the elastic modulus of the FRP layer, is the elastic modulus of the reinforced concrete layer; is the distance between any point in the FRP layer and the center of the cavern; It is the distance from any point in the reinforced concrete layer to the center of the cavern.

[0081] The radial elastic displacement of the surrounding rock layer is:

[0082] (13)

[0083] 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.

[0084] Combine Figure 4 As shown in the figure, according to the continuity of radial stress and equal boundary displacement 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, the calculation formula can be obtained:

[0085] (14)

[0086] (15)

[0087] (16)

[0088] (17) (18)

[0089] By substituting the known parameters, we can get the unknown constants 、 and the contact stress between the surrounding rock layer and the reinforced concrete layer .

[0090] S3.3 Calculate whether the fiberglass layer and reinforced concrete layer are damaged:

[0091] The stress of each structure can be calculated through the stress equations corresponding to the FRP layer and the reinforced concrete layer. The safety factor method is used to determine whether the FRP layer and the reinforced concrete layer are damaged. The FRP layer and the reinforced concrete layer should meet the following conditions:

[0092] (19)

[0093] (20)

[0094] Where, is the ultimate tensile strength of the FRP layer, is the maximum hoop stress of the FRP layer; is the hoop tension of the reinforced concrete layer, is the design value of tensile strength of reinforcement; is the cross-sectional area of ​​the reinforcement; n is the safety factor, which is selected according to the specific project.

[0095] The design method of this embodiment is based on the stress conditions of the compressed air energy storage reservoir and the operating characteristics of the composite toughness sealing lining structure. In the first stage, during the empty reservoir phase, the surrounding rock pressure and water pressure are defined as being entirely borne by the reinforced concrete layer. The surrounding rock pressure, water pressure, and internal pressure of the reinforced concrete layer are calculated, and cross-section design is performed. In the second stage, during the initial inflation phase, the flexible cushion layer is defined as bearing no load, and the FRP layer and reinforced concrete layer are decoupled. During this process, the inflation pressure is entirely borne by the FRP layer. The thickness of the flexible cushion layer is used as the radial deformation of the FRP layer, and the inflation pressure and internal pressure of the FRP layer are calculated. In the later stages of the inflation phase and during the full reservoir operation phase, the FRP layer and reinforced concrete layer are defined as being tightly bonded and sharing the internal reservoir gas pressure with the surrounding rock. The full reservoir operating pressure is used as the calculated load, and the stresses on the FRP layer (using the result of step S1 as the initial state of the FRP layer in this phase), reinforced concrete layer, and surrounding rock are calculated. The cross-section design is then performed with an appropriate safety factor. This method can reflect the stress distribution of each structure in the compressed air energy storage reservoir, thereby quickly determining the material and thickness selection for each structure and saving the cost of the underground gas storage cavern.

[0096] Example 3:

[0097] According to the design method described in Example 2, for a compressed air energy storage facility under construction, the specific process includes:

[0098] Step S1: For a certain anhydrite mining area, determine the elastic modulus of the surrounding rock through on-site investigation =32.61GPa, Poisson's ratio =0.15, according to the engineering requirements, the cavern depth is given =89m, the reservoir section is circular, 100m long, gas storage scale Not less than 5000m 3 , full warehouse working pressure =10MPa, excavation radius =5m.

[0099] According to geological data, the BQ of the site is 658.71 and the rock density is 29.40KN / m 3 , referring to the "TB10003-2016 Railway Tunnel Design Code", it is determined to be a deep buried project. According to the tunnel surrounding rock level, the surrounding rock level is classified as Level I. The vertical surrounding rock pressure at a given burial depth is obtained. =2.78MPa.

[0100] Horizontal surrounding rock pressure Depends on vertical rock pressure and surrounding rock grade, which can be obtained by referring to Table 1 according to experience.

[0101] Table 1 Reference table of horizontal surrounding rock pressure of deep buried caverns

[0102]

[0103] According to Table 1, =0.

[0104] After investigation, the effective water head from the groundwater level to the center of the cavern was obtained. It is 13m.

[0105] According to the surrounding rock information and groundwater activity, the reduction factor β is obtained by referring to the "SL279-2016 Hydraulic Tunnel Design Code" e =0.2, and the water pressure P is obtained by using the reduction coefficient method. w =26kPa.

[0106] Table 2 Water pressure reduction coefficient β e surface

[0107]

[0108] Based on the surrounding rock pressure and water pressure, and considering the full reservoir working pressure, a double-layer reinforced concrete lining was installed, referencing the "GB50010-2010 Code for Design of Concrete Structures" and the "SL279-2016 Code for Design of Hydraulic Tunnels." HRB400 steel was selected, with a Poisson's ratio of 0.3 and an elastic modulus of 200 GPa. C40 concrete was selected, 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 concrete thickness was set at 0.4 m, and the inner diameter was 4.6 m. Reinforcement was calculated using the boundary value method.

[0109] Step S2: Query relevant cases and preliminarily determine to use epoxy resin fiberglass as the fiberglass layer material, with an elastic modulus of 10 GPa, a Poisson's ratio of 0.25, and a tensile strength of 320 MPa. The fiberglass layer thickness is preliminarily set to 0.15 m and the inner diameter is 4.4 m.

[0110] Calculating the deformation of the FRP layer when it bears the full storage pressure, formula (2) shows that the outer boundary deformation at this time is 0.14m. Due to the good condition of the surrounding rock, the internal pressure borne by the FRP layer is assumed to be 30% of the full storage pressure. The initial thickness of the rubber cushion layer is set at b = 0.05m, and the gap between the rubber cushion layer and the reinforced concrete layer is filled with concrete. Substituting b = 0.05m into formula (2) calculates the internal pressure borne by the FRP layer at this time, q0 = 2.274 MPa.

[0111] Step S3: The internal pressure of the FRP layer calculated in step S2 is taken as the initial state of the later inflation period. The deformation of the inner boundary of the FRP layer at this time is calculated by formula (3): =0.05m. The initial state of the FRP layer in the late inflation stage and the full storage operation stage is calculated by formulas (4)-(5), and the known parameters are substituted into formulas (14)-(18) to obtain the corresponding undetermined constants and contact stresses. The stress and displacement of each structure in the late inflation stage and the operation stage can be obtained by formulas (7)-(13). Superimposed on the force of the FRP layer in the early inflation stage, the load borne 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%.

[0112] 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 approximately 4496.86 kN. According to formulas (19) and (20), the structure is within the safety range and meets the design requirements.

[0113] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A composite toughness 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 reinforced plastic layer arranged in sequence from the outside to the inside. The reinforced concrete layer is arranged according to the surrounding rock pressure and water pressure. The fiberglass reinforced plastic layer is used to seal the high-pressure air and bear the internal pressure of the reservoir. The flexible cushion layer is used to reserve deformation space for the fiberglass reinforced plastic layer so that the formed composite toughness sealing lining structure can cooperate with the surrounding rock to bear the force; The design method of the composite toughness sealing lining structure of the compressed air energy storage reservoir includes: During the empty reservoir stage, the surrounding rock pressure and water pressure are calculated based on the assumption that they are all borne by the reinforced concrete layer, and the reinforced concrete layer is set accordingly; At the initial inflation stage, the initial inflation pressure and the internal pressure of the FRP layer are calculated based on the assumption that the initial inflation pressure is entirely borne by the FRP layer and the thickness of the flexible cushion layer is taken as the radial deformation of the FRP layer; In the late inflation stage and full storage operation stage, the increment of the full storage working pressure relative to the initial inflation pressure is used as the calculation load to calculate the stress on the FRP layer, reinforced concrete layer and surrounding rock. Based on the stress on the FRP layer and reinforced concrete layer, it is determined whether damage has occurred. When the FRP layer and reinforced concrete layer have not been damaged and meet the set safety factor, a sealed lining structure that meets the design requirements is obtained.

2. A composite toughness sealing lining structure for 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 glass fiber reinforced plastic layer are circular.

3. A composite toughness 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 the elastic modulus of the surrounding rock, and the elastic modulus of the flexible cushion layer is smaller than the elastic modulus of the surrounding rock.

4. The composite toughness sealing lining structure of a compressed air energy storage reservoir according to claim 1 is characterized in that: The calculation method of the surrounding rock pressure is: First, determine the surrounding rock mechanical parameters, judge the surrounding rock grade, set the cavern burial depth, gas storage capacity, full storage working pressure, excavation radius, and calculate the vertical and horizontal surrounding rock pressures; The water pressure is calculated as follows: Obtain the acting water head from the groundwater level to the center of the cavern, and calculate the water pressure by taking the water pressure as the surface force acting on the outer boundary of the reinforced concrete layer.

5. The composite toughness sealing lining structure of a compressed air energy storage reservoir according to claim 1 is characterized in that: Calculate the outer boundary deformation of the FRP layer when it is subjected to full warehouse working pressure; Based on the fact that the thickness of the flexible cushion layer is equal to the deformation of the outer boundary of the FRP layer, the internal pressure borne by the FRP layer is calculated.

6. A composite toughness sealing lining structure for a compressed air energy storage reservoir according to claim 5, characterized in that: The calculation method of the outer boundary deformation of the glass fiber reinforced plastic layer is: Based on the thick-walled cylinder theory, the displacement expression of the FRP layer under full storage working pressure is obtained; according to the outer boundary radius of the FRP layer and the displacement expression, the outer boundary deformation of the FRP layer under full storage working pressure is obtained.

7. The composite toughness sealing lining structure of a compressed air energy storage reservoir according to claim 1 is characterized in that: For the FRP layer and reinforced concrete layer, the initial state is taken as the initial state; according to the theory of elastic mechanics, the stress and displacement of the FRP layer and reinforced concrete layer are calculated respectively, and the radial elastic displacement of the surrounding rock layer is calculated; According to the continuity of radial stress and the equality of boundary displacement between the inner and outer boundaries of the FRP layer, the inner and outer boundaries of the reinforced concrete layer and the inner side of the surrounding rock layer, the contact stress between the surrounding rock and the reinforced concrete layer is obtained.

8. The composite toughness sealing lining structure of a compressed air energy storage reservoir according to claim 1 is characterized in that: The maximum hoop stress of the FRP layer and reinforced concrete layer is calculated by the stress equation, and the safety factor method is used to determine whether the FRP layer and reinforced concrete layer are damaged.

9. The composite toughness sealing lining structure of a compressed air energy storage reservoir according to claim 1 is characterized in that: 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 storage stage, the initial inflation stage, the late inflation stage and the full storage operation stage is repeated.

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