A composite structure for compensating axial deformation of artificially lined caverns

Abstract

The present application relates to a composite structure for compensating for axial deformation of an artificially lined cavern, comprising a surrounding rock mass, a concrete lining, and a steel lining sealing layer, which are sequentially arranged within the artificially lined cavern. The steel lining sealing layer comprises an annular steel liner and at least one corrugated steel liner, wherein the corrugated steel liner comprises a corrugated section and a straight connecting section. The corrugated section comprises a plurality of semicircular corrugations, which are connected end to end and arranged in a wavy structure along the axial direction of the corrugated section. The straight connecting sections are located on both sides of the corrugated section along the axial direction, connecting the corrugated section and the annular steel liner. This composite structure can compensate for axial deformation caused by reciprocating temperature changes during the operation of compressed gas energy storage, reduce the risk of axial buckling or tension damage to the steel liner, and thus ensure the long-term airtightness and safety of the gas storage reservoir.

Description

Technical Field

[0001] The present application relates to the technical field of compressed air energy storage, and in particular to a composite structure for compensating for axial deformation of an artificially lined cavern. Background Art

[0002] Artificial lined caverns are one of the main types of compressed air storage, with wide-ranging locations, large scale, and environmental friendliness. In order to ensure the stability and airtightness of the cavern under high internal pressure, a composite structure needs to be constructed. The composite structure is generally composed of a sealing layer, a lining, and surrounding rock. At present, the sealing layer mostly uses a thin steel lining. During the operation of compressed air energy storage, the temperature changes cyclically, and the composite structure (especially the steel lining) will have thermal expansion and contraction effects due to temperature changes. The circumferential stress of the steel lining is mainly caused by the high internal pressure, and the thermal stress generated during thermal expansion is beneficial to the circumferential force. However, in the axial direction of the steel lining, the stress generated by the air pressure can be ignored. The limited thermal expansion and contraction of the steel lining may cause warping and tensile damage of the steel lining. Therefore, certain temperature deformation compensation measures need to be taken for the axial direction of the steel lining. However, the composite structure at this stage has not taken effective measures to this end. Summary of the Invention

[0003] An embodiment of the present application provides a composite structure for compensating for axial deformation of an artificially lined cavern. The composite structure can compensate for the axial deformation caused by reciprocating temperature changes during the operation of compressed gas energy storage, reduce the risk of axial buckling or tension damage of the steel lining, and thus ensure the long-term airtightness and safety of the gas storage facility.

[0004] The composite structure for axial deformation compensation of an artificial lined cavern provided in an embodiment of the present application includes a surrounding rock mass, a concrete lining and a steel lining sealing layer, wherein the surrounding rock mass, the concrete lining and the steel lining sealing layer are sequentially arranged in the artificial lined cavern; the steel lining sealing layer includes an annular steel lining and at least one corrugated steel lining, the corrugated steel lining has a corrugated section and a straight connecting section, the corrugated section includes a plurality of semicircular corrugations, the plurality of semicircular corrugations are connected end to end and are arranged in a wavy structure along the axial direction of the corrugated section, the straight connecting section is located on both sides of the corrugated section along the axial direction, and the straight connecting section connects the corrugated section and the annular steel lining.

[0005] In addition, the composite structure provided in the embodiments of the present application may also have the following additional technical features:

[0006] In an optional solution, if the thermal expansion and contraction deformation of the steel lining sealing layer caused by temperature is defined as ΔL, then ΔL=αΔTL1, where α is the thermal expansion coefficient, ΔT is the temperature change value, and L1 is the total length of the artificial lining cavern;

[0007] The compression deformation of the corrugated steel lining is L c The elongation deformation of the corrugated steel lining is Lt , then L c =dN / 2, Where d is the diameter of the semicircular corrugation, and N is the number of semicircular corrugations;

[0008] Then L c and L t Satisfies the inequality:

[0009]

[0010] In an optional solution, the straight connecting section is flush with the wall surface of the annular steel liner, and the semicircular corrugations of the corrugated section on the side close to the straight connecting section are flush with the wall surface of the annular steel liner; the corrugated section also includes a transition section, which is a quarter circle and connects the corrugated section and the straight connecting section.

[0011] In an optional solution, the radius of the annular steel lining is 4 to 6 m, the thickness is 10 to 20 mm, and the material is high-strength steel; the number of the semicircular corrugations is 5 to 10.

[0012] In an optional scheme, the composite structure also includes a cushion layer and a support structure, wherein the support structure is arranged between the surrounding rock mass and the concrete lining, the cushion layer can be deformed, and the cushion layer is tightly arranged between the steel lining sealing layer and the concrete lining, and the thickness of the cushion layer gradually becomes thinner from the corrugated steel lining to the annular steel lining, and the gradually thinning transition distance is not less than 1m.

[0013] In an optional solution, the thickness of the cushion layer is at least 0.01 m greater than the height of the corrugated section, and the material of the cushion layer is clay or rubber.

[0014] The beneficial effects of the embodiments of the present application are:

[0015] The composite structure in this embodiment of the application, through its corrugated steel lining, can partially absorb lateral deformation, effectively reducing thermal stress in the axial direction of the gas storage reservoir caused by temperature fluctuations. This mitigates axial tension or warping damage caused by thermal barriers and contraction, thereby ensuring the long-term airtightness and safety of the gas storage reservoir. Furthermore, the corrugated steel lining can be deployed in areas with locally weak surrounding rock, where it can provide axial temperature compensation while also resisting some lateral deformation.

[0016] It should be understood that the foregoing general description and the following detailed description are merely illustrative and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the arrangement of the composite structure provided in this application in an artificial lined cavern;

[0018] Figure 2 for Figure 1 Schematic diagram of the cross-sectional structure of the artificial lined cavern at the corrugated steel lining;

[0019] Figure 3 This is a schematic structural diagram of a specific embodiment of the corrugated steel lining provided in this application.

[0020] Figure numerals: surrounding rock mass 1, concrete lining 2, annular steel lining 3, corrugated steel lining 4, corrugated section 41, straight connecting section 42, semicircular corrugation 43, transition section 44, cushion layer 5, supporting structure 6, artificial lined cavern 7.

[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application. DETAILED DESCRIPTION

[0022] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0023] It should be clear that the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0024] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0025] It should be understood that the term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0026] It should be noted that the directional words such as "upper", "lower", "left", and "right" described in the embodiments of the present application are described based on the angles shown in the accompanying drawings and should not be understood as limiting the embodiments of the present application. In addition, in the context, it should be understood that when it is mentioned that an element is connected to another element "on" or "under", it can not only be directly connected to the other element "on" or "under", but also be indirectly connected to the other element "on" or "under" through an intermediate element.

[0027] like Figure 1-3 As shown, an embodiment of the present application provides a composite structure for compensating for axial deformation in an artificially lined cavern. The composite structure comprises a surrounding rock mass 1, a concrete lining 2, and a steel lining sealing layer, which are sequentially arranged within an artificially lined cavern 7. The steel lining sealing layer comprises an annular steel liner 3 and at least one corrugated steel liner 4. The structural section where the corrugated steel liner 4 is located is also called a compensation section. Generally, the annular steel liner 3 has a radius of 4 to 6 meters and a thickness of 10 to 20 mm, and is made of high-strength steel. The corrugated steel lining 4 is annular in shape and wavy in the axial direction. Specifically, the corrugated steel lining 4 has a corrugated section 41 and a straight connecting section 42. The corrugated section 41 includes multiple semicircular corrugations 43. The multiple semicircular corrugations 43 are connected end to end and arranged in a wavy structure along the axial direction of the corrugated section 41. The straight connecting section 42 is located on both sides of the corrugated section 41 along the axial direction. The straight connecting section 42 connects the corrugated section 41 and the annular steel lining 3, that is, the top and bottom of the corrugated section 41 are semicircular, each semicircle is a corrugation, and the horizontal sections at both ends of the corrugated steel lining 4 are straight connecting sections 42.

[0028] In this embodiment, the composite structure's corrugated steel lining (4) absorbs some lateral deformation, effectively reducing thermal stress in the gas storage reservoir's axial direction caused by temperature fluctuations. This mitigates axial tension or warping damage caused by thermal barriers and contraction, thereby ensuring the long-term airtightness and safety of the gas storage reservoir. Furthermore, the corrugated steel lining (4) can be deployed in areas with locally weak surrounding rock, providing axial temperature compensation while also resisting some lateral deformation.

[0029] In a specific embodiment, the size and number of the semicircular corrugations 43 in the corrugated steel lining 4 are related to the amplitude of the temperature change in the cavern and the thermal expansion coefficient of the steel lining. The compression of the corrugated steel lining 4 needs to be greater than or equal to the thermal expansion deformation caused by the high temperature of the total steel lining of the cavern. Similarly, the elongation of the corrugated steel lining 4 needs to be greater than or equal to the cold contraction deformation caused by the low temperature of the total steel lining of the cavern.

[0030] Specifically, if the thermal expansion and contraction deformation of the steel lining sealing layer due to temperature is defined as ΔL, then ΔL=αΔTL1, where α is the thermal expansion coefficient, ΔT is the temperature change value, and L1 is the total length of the artificial lining cavern 7;

[0031] The compression deformation of the corrugated steel lining 4 is L c The elongation deformation of the corrugated steel lining 4 is L t , then L c =dN / 2, Wherein, d is the diameter of the semicircular corrugation 43, and N is the number of the semicircular corrugations 43;

[0032] Then L c and L t Satisfies the inequality:

[0033]

[0034] The larger diameter value obtained from the above inequality is the minimum corrugation circle diameter required to meet deformation compensation requirements. This inequality forms the design basis for corrugated segment 41. Furthermore, to avoid excessive axial deformation of a single compensating segment, the number of corrugations in a compensating segment is odd, generally limited to approximately 5 and not exceeding 10. The corrugation size is also constrained by the manufacturing process and other structural dimensions; an appropriate size is sufficient, and this will not be discussed in detail in this article. Furthermore, to achieve uniform compensation, multiple compensating segments can be evenly spaced along the cavity axis.

[0035] like Figure 2 As shown, in a specific embodiment, the straight connecting section 42 is flush with the wall surface of the annular steel liner 3 and can be welded to the annular steel liner 3 to form a steel liner sealing layer. The semicircular corrugations 43 of the corrugated section 41 on the side close to the straight connecting section 42 are flush with the wall surface of the annular steel liner 3. The corrugated section 41 also includes a transition section 44, which is a quarter circle and connects the corrugated section 41 and the straight connecting section 42.

[0036] like Figure 2 As shown, in a specific embodiment, the composite structure also includes a cushion layer 5 and a support structure 6. The support structure 6 is arranged between the surrounding rock mass 1 and the concrete lining 2. The cushion layer 5 can be deformed. The cushion layer 5 is tightly arranged between the steel lining sealing layer and the concrete lining 2, and the thickness of the cushion layer 5 gradually becomes thinner from the corrugated steel lining 4 to the annular steel lining 3.

[0037] Specifically, a cushion layer 5 is backfilled behind the compensation joint. The cushion layer 5 can be made of clay or rubber, which fits tightly with the steel lining and lining and can undergo large deformation. The thickness of the cushion layer 5 is at least 0.01m greater than the corrugation height (equal to the diameter d). The thickness gradually becomes thinner in the connection area with the conventional steel lining, and the transition distance is at least 1m. The back cushion layer 5 allows the compensation joint to deform and is not constrained by concrete. The back of the remaining annular steel lining 3 sections is used to backfill the concrete lining 2. The support system is constructed during the excavation of the cavern. During the later backfilling of the concrete lining 2, the steel lining sealing layer, cushion layer 5, concrete lining 2, support structure 6 and surrounding rock mass 1 form a cavern composite structure.

[0038] Example 1:

[0039] A tunnel-like structure houses an artificially lined cavern for compressed air energy storage. The design has a cross-sectional diameter of 10 meters, a net volume of 200,000 cubic meters, and a total length of approximately 2,600 meters. Each cavern is a 520-meter-long strip, with one horizontal and four vertically aligned, spaced to ensure stability. A composite cavern structure was designed, using a 0.7 mm / s (600 MPa) steel lining with a thickness of 20 mm, based on surrounding rock parameters, burial depth, cavern diameter, and operating pressure.

[0040] The corresponding thermal expansion coefficient α of this steel lining is 0.012mm / m·℃. It is known that the temperature change is most significant during the first inflation and discharge. The highest temperature during inflation can be 80℃ higher than the normal temperature. Based on this calculation, the thermal expansion length of each cavern can reach 0.4992m; when deflated, the temperature can drop to below zero, which is about 30℃ lower than the normal temperature, and each cavern shrinks by 0.1872m.

[0041] Each longitudinal cavern has one compensating section, with five corrugations in the center and a semicircular and straight plate transition on each side. The straight plate sections are welded to the conventional circular steel lining. Two compensating sections are evenly spaced in the transverse caverns, each with three corrugations. Taking the larger value of the inequality, the designed corrugation circle diameter is 0.2m.

[0042]

[0043] A rubber cushion layer is placed behind the corrugations, with a maximum thickness of 0.22m, tapering from 0.22m to 0m at 1m between the compensation joint and the conventional steel lining. The excavated section of the cavern is 5.8m, with an initial sprayed concrete depth of 0.02m. 3m-long anchor bolts are designed for support. Plain concrete is backfilled between the cavern wall and the steel lining to form the lining. The concrete lining measures 0.76m at its thickest point and 0.54m at its thinnest. This ultimately creates a sealed composite structure for the gas storage cavern. To facilitate construction, the compensation joint is typically placed in the center of the cavern, away from plugs, forks, or blind ends.

[0044] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. 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 structure for compensating axial deformation of an artificially lined cavern, characterized in that: The invention comprises a surrounding rock mass, a concrete lining and a steel lining sealing layer, wherein the surrounding rock mass, the concrete lining and the steel lining sealing layer are sequentially arranged in an artificial lined cavern; the steel lining sealing layer comprises an annular steel lining and at least one corrugated steel lining, the corrugated steel lining having a corrugated section and a straight connecting section, the corrugated section comprising a plurality of semicircular corrugations, the plurality of semicircular corrugations being connected end to end and arranged in a wavy structure along the axial direction of the corrugated section, the straight connecting section being located on both sides of the corrugated section along the axial direction, and the straight connecting section connecting the corrugated section and the annular steel lining; The thermal expansion and contraction deformation of the steel lining sealing layer caused by temperature is defined as ,but , where is the coefficient of thermal expansion, is the temperature change value, is the total length of the artificial lined cavern; The compression deformation of the corrugated steel lining is The elongation deformation of the corrugated steel lining is ,but , , where is the diameter of the semicircular corrugation, is the number of semicircular ripples; but and Satisfies the inequality: ； The straight connecting section is flush with the wall surface of the annular steel liner, and the semicircular corrugations of the corrugated section on the side close to the straight connecting section are flush with the wall surface of the annular steel liner; the corrugated section also includes a transition section, which is a quarter circle and connects the corrugated section and the straight connecting section; It also includes a cushion layer and a support structure, the support structure is arranged between the surrounding rock mass and the concrete lining, the cushion layer can be deformed, the cushion layer is tightly arranged between the steel lining sealing layer and the concrete lining, and the thickness of the cushion layer gradually becomes thinner from the corrugated steel lining to the annular steel lining, and the gradually thinning transition distance is not less than 1m.

2. The composite structure for compensating axial deformation of an artificial lining cavern according to claim 1, characterized in that: The radius of the annular steel lining is 4-6m, the thickness is 10-20mm, and the material is high-strength steel; the number of the semicircular corrugations is 5-10.

3. The composite structure for compensating axial deformation of an artificial lining cavern according to claim 1, characterized in that: The thickness of the cushion layer is at least 0.01 m greater than the height of the corrugated section, and the material of the cushion layer is clay or rubber.

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