Compressed air energy storage artificial cavern structure under local soft rock stratum condition and construction method

Abstract

The invention relates to the technical field of compressed air energy storage, in particular to a compressed air energy storage artificial cavern structure under the local soft rock stratum condition and a construction method. A plurality of pipelines are arranged in the soft rock cavern, and the two ends of the pipelines are connected with the steel linings in the hard rock cavern in a sealed mode through the end sealing plates, so that the sealing performance and the gas circulation performance of the gas storage cavern are guaranteed; the high internal pressure is mainly borne by the steel pipe, and the small-proportion internal pressure transmits the internal pressure of the pipeline to surrounding rock through concrete between the pipelines. Compared with a steel lining in a hard rock cavern, a plurality of steel pipes with smaller diameters are arranged in the soft rock cavern, so that the internal pressure load sharing rate of soft surrounding rock is favorably reduced, the deformation of the surrounding rock is reduced, and the structural safety is ensured. According to the scheme, a new design concept is provided for application of the compressed air underground gas storage cavern structure under the condition of the local soft rock stratum, and the flexibility of site selection is improved.

Description

Technical Field

[0001] The invention relates to the technical field of compressed air energy storage, and in particular to a compressed air energy storage artificial cavern structure and a construction method under local soft rock conditions. Background Art

[0002] Compressed air energy storage, as a large-scale physical energy storage technology, is regarded as a large-scale energy storage technology with great potential due to its outstanding advantages such as large energy storage capacity, long life, high efficiency, fast response speed, safety and reliability. It will occupy an important position in the future energy storage industry. The underground gas storage cavern is an important part of the compressed air energy storage system and is the technical key to ensure its operating performance and reliability. The gas storage cavern is a tunnel-type underground cavern structure with the advantages of large storage scale, flexible site selection, low construction cost and little impact on the surrounding environment. Figure 1 , Figure 2 As shown, the gas storage cavern usually adopts a thin steel lining 3 (a steel plate with a thickness of 6 mm to 20 mm) as a sealing layer. The steel lining 3 is cylindrical, and an integrally cast reinforced concrete lining 2 is arranged between the steel lining 3 and the surrounding rock 1 as a force transmission structure layer of the sealing layer to transfer the high internal pressure load to the surrounding rock 1.

[0003] When the surrounding rock of the underground gas storage cavern is hard rock, the deformation modulus of the rock mass is large (E≥5GPa). As the main internal pressure bearer, the deformation of the gas storage cavern is small under the action of high internal pressure gas, the cracks of the reinforced concrete lining are controllable, and the stress-strain level of the sealing steel lining is low, which can adapt to the alternating loads during the compressed air storage process. However, when the surrounding rock of the underground gas storage cavern is partially a weak rock layer (the deformation modulus of the rock mass is small, E<5GPa, or the weak rock layer is Class IV surrounding rock), the surrounding rock of the gas storage cavern will produce a large deformation after being compressed under the action of high internal pressure, causing uncontrollable cracks in the reinforced concrete lining, and the deformation of the sealing steel lining is too large, so that it exceeds the yield stress strain of the steel lining, resulting in fatigue failure of the steel lining when the fatigue life is less than the number of cycles of compressed air in the gas storage cavern. In severe cases, the stress of the lining steel and the steel lining will exceed the ultimate strength of the steel and break, resulting in gas leakage accidents in the gas storage cavern.

[0004] Therefore, when there are local weak rock formations in the surrounding rock of the underground gas storage cavern, the thin steel lining solution in the hard rock cavern (i.e., the part of the cavern where the gas storage cavern is located in the hard rock area) will not be able to simultaneously meet the force requirements of the weak rock cavern (the part of the cavern where the gas storage cavern is located in the weak rock area) under high-pressure gas storage conditions; the weak rock section has higher requirements for the sealing steel lining, and it is obviously inappropriate to abandon the construction of the gas storage cavern because of the corresponding section. Therefore, it is necessary to optimize and improve the sealing structure of the underground gas storage cavern under the condition of local weak rock formations to make the structure safe. Summary of the invention

[0005] The purpose of the present invention is to provide an artificial cavern structure for compressed gas energy storage under local soft rock conditions in order to solve the problem that when there are local soft rock layers in the surrounding rock of an underground gas storage cavern, the thin steel lining solution in the hard rock cavern cannot simultaneously meet the stress requirements of the soft rock layers.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A compressed gas energy storage artificial cavern structure under local soft rock conditions, comprising a gas storage cavern, wherein the gas storage cavern comprises a hard rock cavern and a soft rock cavern, and the cross-sectional excavation dimensions of the hard rock cavern and the soft rock cavern are consistent;

[0008] The hard rock cavern is provided with a first reinforced concrete lining and a steel lining in sequence from the surrounding rock side;

[0009] A second reinforced concrete lining and at least one pipe are provided in the soft rock cavern. The cross section of the pipe is smaller than that of the steel lining. Both ends of the pipe are connected to the steel lining in the hard rock cavern on the corresponding side through head plates. The pipe is communicated with the hard rock cavern. Concrete is filled in the gap between the head plate, the pipe and the second reinforced concrete lining.

[0010] The present invention solves the problem that the uniform thin steel lining does not meet the stress and sealing requirements in the soft rock area by making local special treatment to the gas storage cavern where it passes through the soft rock area. Specifically, on the basis of connecting the excavated hard rock cavern and the soft rock cavern, the present invention sets at least one pipe with a smaller cross section in the soft rock cavern to connect the hard rock caverns on both sides, which can reduce the thickness of the pipe, ensure the gas flowability of the gas storage cavern, and ensure the safety and convenience of pipeline construction; concrete is filled between the pipe and the second reinforced concrete lining for force transmission; the pipe is connected to the steel liner in the hard rock cavern through the head plate, so as to achieve the sealing of the cavern, and the pressure on the head plates at both ends of the soft rock cavern can be transmitted through concrete to maintain balance.

[0011] The above structure is helpful to reduce the internal pressure load sharing rate of soft surrounding rock and reduce the deformation of surrounding rock, thereby ensuring the safety of the structure. In the above cavern structure, the pipeline can directly adopt the finished pipeline with high pressure bearing capacity in the existing technology to achieve self-pressure bearing, or it can select the appropriate wall thickness and material strength grade according to the self-determined pipe diameter size, so that the pipeline bears part of the internal pressure, and part of the internal pressure is transmitted to the surrounding rock through concrete. The number, inner diameter, wall thickness and material strength grade of the pipeline can be reasonably selected according to the actual working conditions, and the size and model of several pipelines can be consistent or inconsistent.

[0012] This scheme provides a new design concept for the application of compressed air underground gas storage cavern construction in local soft rock conditions, avoiding the situation where the gas storage cavern cannot be set up due to poor surrounding rock in some sections, and increasing the flexibility of the site selection of the gas storage cavern.

[0013] As a preferred solution of the present invention, the edge of the head plate extends out of the end of the steel liner, and the head plate and the steel liner are connected in a T-shape, which is beneficial to ensure the sealing performance of the cavern and has better force bearing capacity.

[0014] As a further preferred embodiment of the present invention, the head plate is in a flat plate structure and is arranged perpendicular to the wall of the gas storage cavern, which is convenient for construction.

[0015] As another possible implementation method, the head plate may also be a curved plate, and the edge of the head plate is arranged to be inclined to the cave wall, which is not limited to the above example.

[0016] As a preferred solution of the present invention, the first reinforced concrete lining and the second reinforced concrete lining are an integrally connected structure, which is convenient for construction.

[0017] The thickness of the first reinforced concrete lining and the second reinforced concrete lining may be consistent or inconsistent. For example, the thickness of the second reinforced concrete lining is greater than the thickness of the first reinforced concrete lining, and the inner diameter of the second reinforced concrete lining may be smaller than the inner diameter of the first reinforced concrete lining.

[0018] As a preferred solution of the present invention, the axial direction of the plurality of pipelines is consistent with the axial direction of the steel liner. As another possible implementation, the pipelines may also be arranged at a certain inclination angle.

[0019] As a preferred solution of the present invention, the wall thickness of the pipeline is greater than the wall thickness of the steel lining. By increasing the wall thickness of the pipeline to improve the pressure bearing capacity of the pipeline, it is also possible to reduce the internal pressure load sharing rate of the soft surrounding rock, reduce the deformation of the surrounding rock, and ensure the safety of the structure. When the wall thickness of the pipeline is increased, the inner diameter of the pipeline can be appropriately increased to increase the gas storage capacity of the cavern.

[0020] As another possible implementation method, the wall thickness of the pipeline may be smaller than the wall thickness of the steel liner, or may be consistent with the wall thickness of the steel liner. Accordingly, the deformation of the soft rock cavern may be controlled by adjusting the inner diameter of the pipeline and the material strength grade.

[0021] As a preferred solution of the present invention, the pipeline includes at least one first pipeline and at least one second pipeline, the diameter of the first pipeline is larger than that of the second pipeline, and at least one of the first pipelines is located below the soft rock cavern so as to be used as a manhole maintenance passage. The number of first pipelines can be more than the second pipelines, less than the second pipelines, or equal, and the number of first pipelines and second pipelines can be reasonably allocated according to actual working conditions.

[0022] As a preferred solution of the present invention, the diameter of the first pipeline is greater than or equal to 3m, which is convenient for construction personnel to pass through during maintenance. The size of the first pipeline can be determined based on the principle of convenient maintenance and in combination with maintenance machinery.

[0023] As a preferred solution of the present invention, the number of the pipes is at least two, and the net gap between the pipes is recommended to be greater than or equal to 300 mm, which facilitates welding construction and facilitates the backfilling and compaction of concrete.

[0024] The present invention also provides a construction method of an artificial cavern structure of compressed air energy storage under the above-mentioned local weak rock formation conditions, comprising the following steps:

[0025] Excavating a gas storage cavern, wherein the gas storage cavern passes through a soft rock layer area, the gas storage cavern includes a hard rock cavern and a soft rock layer cavern, and the excavation section of the hard rock cavern is consistent with the excavation section of the soft rock layer cavern;

[0026] Constructing reinforced concrete lining, end plates and pipelines, wherein the end plates are pre-buried in the reinforced concrete lining, the reinforced concrete lining includes a first reinforced concrete lining and a second reinforced concrete lining, the end plates are pre-reserved with grouting holes and holes for pipeline docking, and both ends of the pipeline are sealed and connected with the end plates on the corresponding sides;

[0027] pouring concrete from the grouting holes, and sealing the grouting holes after the concrete pouring is completed;

[0028] A steel lining is constructed in the hard rock cavern, and the steel lining is sealed and connected to the head plate.

[0029] Among them, the head plate can be constructed as a whole or in blocks; the construction sequence can be to first fix the head plates at both ends of the soft rock cavern as a whole, then construct the reinforced concrete lining, and then insert the pipe between the two head plates; or first construct a part of the reinforced concrete lining to play a part of the support role, then construct the head plate on either side, and then place the pipe, double-sided weld one end of the pipe to the head plate, temporarily fix the pipes, and then continue to construct the head plate on the other side; or first place some pipes, and the pipes can be fixed in layers by backfilling gravel and other measures, and then the head plates on both sides are made at the same time, and the head plates on both sides are welded in blocks from bottom to top in turn, and the pipes and head plates of the corresponding layers are welded and installed in place until all the sections are finally blocked, and then high-pressure grouting is performed into the inside of the two head plates, and backfilled densely, not limited to the above examples.

[0030] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0031] This scheme sets a smaller diameter pipe in a large diameter cavern under soft rock conditions to bear the internal pressure, thereby reducing the internal pressure load sharing rate of the soft surrounding rock, reducing surrounding rock deformation, and ensuring structural safety. The structure is safe, reliable, and easy to implement. It is suitable for compressed air energy storage underground gas storage cavern sites where the surrounding rock is mainly hard rock and there are local soft rock formations, which increases the flexibility of site selection. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a cross-sectional view of a gas storage cavern in the prior art;

[0033] Figure 2 yes Figure 1 The cross-sectional view at AA in FIG.

[0034] Figure 3 It is a cross-sectional view of a compressed air energy storage artificial cavern structure under local weak rock conditions in Example 1;

[0035] Figure 4 yes Figure 3 The cross-sectional view at BB in FIG.

[0036] Figure 5 It is a cross-sectional view of another artificial cavern structure of compressed air energy storage under local weak rock conditions in Example 1;

[0037] Figure 6 It is a cross-sectional view of a compressed air energy storage artificial cavern structure under local weak rock conditions in Example 2;

[0038] Figure 7 It is a longitudinal section of an artificial cavern structure for compressed air energy storage under local weak rock conditions in Example 2.

[0039] Icon: 1-surrounding rock; 2-reinforced concrete lining; 3-steel lining; 4-first pipeline; 5-second pipeline; 6-concrete; 7-head plate. DETAILED DESCRIPTION

[0040] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0041] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0042] Example 1

[0043] A compressed gas energy storage artificial cavern structure under local weak rock conditions, such as Figure 3 , Figure 4 As shown, it includes a gas storage cavern, in which a steel lining 3, a reinforced concrete lining 2, a head plate 7 and a plurality of pipes are arranged. Among them, the gas storage cavern is divided into a soft rock cavern and a hard rock cavern according to the geological conditions of the surrounding rock 1. The cross-sectional excavation range of the soft rock cavern and the thickness of the reinforced concrete lining 2 are the same as those of the hard rock cavern. The reinforced concrete lining 2 includes a first reinforced concrete lining and a second reinforced concrete lining. In this embodiment, the first reinforced concrete lining and the second reinforced concrete lining are an integrated structure. The reinforced concrete lining arranged in the hard rock cavern is the first reinforced concrete lining, and the reinforced concrete lining arranged in the soft rock cavern is the second reinforced concrete lining. The soft rock cavern is not provided with a sealed steel liner 3, and the steel liner 3 is arranged in the hard rock cavern; a pipeline is arranged in the soft rock cavern along the axial direction, the cross section of the pipeline is smaller than the cross section of the steel liner 3, and both ends of the pipeline are respectively connected with the hard rock cavern on the corresponding side; a circular head plate 7 is arranged at the junction of the hard rock and soft rock sections, and the head plate 7 is provided with a perforation at the position where the pipeline passes through, and the hole size is adapted to the pipeline diameter, and the two ends of the pipeline are sealed and connected with the steel liner 3 at the corresponding end through the head plate 7; in the soft rock cavern section, dense concrete 6 is backfilled in the gap outside the pipeline to transmit pressure.

[0044] Specifically, in this embodiment, Figure 3As shown, there are several pipelines, including a first pipeline 4 and several second pipelines 5. The diameter of the first pipeline 4 is larger than that of the second pipeline 5. The first pipeline 4 is located at the lower side of the section of the soft rock cavern so as to be used for the passage of people and equipment during maintenance. The remaining several second pipelines 5 with small diameters are evenly arranged at the rest of the section, and the number can be determined according to the requirements of the gas storage volume. In this embodiment, the first pipeline 4 and the second pipeline 5 are both arranged inside the soft rock cavern and wrapped by plain concrete 6. As another possible implementation method, a first pipeline 4 can also be arranged on the lower side of the second reinforced concrete lining, and the rest of the lining is covered with second pipelines 5. A certain distance is reserved between the pipelines and filled with concrete, such as Figure 5 shown.

[0045] In this embodiment, the wall thickness of the large-diameter first pipeline 4 can be determined according to the calculation method of underground buried pipes in the "Specifications for the Design of Hydropower Station Penstock" (NB / T35056-2015), so that the wall thickness of the first pipeline 4 meets the condition of soft rock formation, and the stress of the first pipeline 4 under the maximum operating gas pressure of the cavern does not exceed the allowable stress of the material itself, thereby reducing the surrounding rock internal pressure sharing rate, reducing the deformation of the soft surrounding rock, and making the cracks of the reinforced concrete lining controllable. In order to facilitate maintenance and access, the diameter of the first pipeline 4 is generally not less than 3m; in order to facilitate transportation, installation, and construction, the pipeline wall thickness is generally not more than 50mm; in order to increase the gas storage volume, the diameter of the large-diameter pipeline should be as large as possible under the condition that the wall thickness is acceptable, and high-strength grade steel can be used when necessary.

[0046] Taking an underground gas storage cavern as an example, the inner diameter of the large-diameter first pipeline 4 is 3m. According to the mechanical parameters of the soft rock formation, the wall thickness is calculated with reference to the calculation method of underground buried pipes in the "Design Specifications for Pressure Steel Pipes of Hydropower Stations" (NB / T35056-2015). When the steel strength grade of the first pipeline 4 is the same as that of the hard rock cavern steel lining 3, the minimum wall thickness of the first pipeline 4 is not less than 46mm, and 50mm is taken in this embodiment.

[0047] The small-diameter second pipeline 5 can use a self-pressurized finished pipeline of the oil and gas industry with a diameter of about 1m. In this embodiment, the second pipeline 5 can use a steel pipe with an outer diameter of 1219mm and an inner diameter of 1175mm, and the maximum gas pressure it can withstand is 15MPa, which meets the self-pressure requirement. In the prior art, a thin steel lining 3 (thickness 6mm to 20mm) with a cross-sectional size equal to the diameter of the gas storage cavern usually yields when subjected to the maximum gas pressure of the cavern under soft rock conditions, and then causes the steel lining seal to fail or the steel lining to break under cyclic loads; if a thickened steel lining solution is used in the sealing structure of the soft rock cavern, then due to the large inner diameter of the cavern, combined with corresponding calculations, the thickness of the steel lining will reach nearly 300mm, and there are great difficulties in welding and installing the steel plate. Therefore, in this embodiment, the gas storage cavern is constructed in the soft rock formation cavern for local special treatment. In the soft rock formation cavern, a number of small-section pipes are used for self-pressure or partial pressure bearing, thereby reducing the inner diameter of the cavern and reducing the wall thickness of the pipe. This not only facilitates the installation and welding between the steel lining and the pipe, but also helps to meet the stress and sealing requirements of the cavern in the soft rock formation area.

[0048] Furthermore, in this embodiment, the thickness of the end plate 7 is the same or close to the wall thickness of the first pipe 4 with a large diameter, and the strength grade of the steel plate is also the same as that of the first pipe 4. The end of the end plate 7 is arranged beyond the end of the steel lining 3 and anchored in the reinforced concrete lining 2. The end of the thin steel lining 3 in the hard rock cavern is welded to the end plate 7 by T-shaped full penetration welding; the end of each pipe in the soft rock cavern is welded to the end plate 7 by full penetration welding, so as to realize the connection between the soft and hard rock caverns and the continuous sealing.

[0049] It should be noted that weak rock formations refer to bedrock with particularly low strength and elastic modulus. Some rock formations are still hard, but become weak rock formations due to weathering or dense cracks and joints, such as Class IV surrounding rock. Some are formed because the rock formation itself is weak. In this article, rock deformation modulus E < 5GPa or Class IV surrounding rock is considered a weak rock formation. Usually, when choosing a cavern construction site, we should try to choose a place with hard rock. However, when the section of the weak rock formation is not long (less than 20m), giving up the construction of the gas storage cavern will greatly limit the site selection.

[0050] In this embodiment, a small-section pipe is arranged in the local soft rock cavern to bear pressure, and the two ends are sealed and connected to the steel lining 3 in the hard rock cavern through the head plate 7 to ensure the sealing and gas flow of the gas storage cavern; a part of the internal pressure of the pipe is transmitted to the surrounding rock 1 through the concrete 6 between the pipes. With the compressed gas energy storage artificial cavern structure under the local soft rock conditions provided by this embodiment, under the high internal pressure of the inflation condition, the small-diameter second pipe 5 can bear pressure by itself; the large-diameter first pipe 4 and the surrounding rock 1 can bear the pressure load together, but the proportion of the internal pressure borne by the first pipe 4 is greater than that borne by the steel lining 3 in the hard rock cavern. Compared with the hard rock cavern, the internal pressure load sharing rate and deformation of the soft surrounding rock 1 are reduced, so that the cracks of the reinforced concrete lining 2 under the soft rock conditions are controllable; further, in this embodiment, the head plate 7 is backfilled with dense concrete 6, and the concrete between the pipes can simultaneously transmit the pressure on the head plates 7 at both ends, so that the two ends are balanced with each other; the steel lining 3, the head plate 7 and the pipe together form a continuous sealing structure, which can meet the sealing requirements.

[0051] Compared with the prior art, this embodiment provides a design scheme for an underground gas storage cavern for compressed air energy storage under weak rock conditions: in the weak rock area, a smaller diameter pipe can be set in a large diameter cavern to bear the internal pressure, thereby reducing the internal pressure load sharing rate of the soft surrounding rock 1, reducing the deformation of the surrounding rock 1, and ensuring the safety of the structure. This scheme is structurally safe, reliable, and easy to implement. It is suitable for the situation where the surrounding rock 1 of the compressed air energy storage underground gas storage plant site is mainly hard rock and there are weak rock formations in some parts, especially when the section of the local weak rock formation section is less than 20m, which increases the flexibility of site selection.

[0052] Example 2

[0053] Based on Example 1, this example also provides a compressed air energy storage artificial cavern structure under local weak rock conditions. Compared with Example 1, the difference of this example is mainly as follows: Figure 6 , Figure 7 As shown, this solution mainly adopts large-diameter first pipes 4 to be evenly distributed in the soft rock layer caverns, and small-diameter second pipes 5 are inserted between the first straight pipes 4.

[0054] Example 3

[0055] Based on Example 1, this embodiment provides a construction method for a compressed air energy storage artificial cavern structure under the above-mentioned local weak rock formation conditions, comprising the following steps:

[0056] Excavate a gas storage cavern, which passes through a soft rock layer area. The gas storage cavern includes a hard rock cavern and a soft rock layer cavern. The excavation section of the hard rock cavern is consistent with the excavation section of the soft rock layer cavern.

[0057] Construct the reinforced concrete lining 2 and the end plate 7, and embed the end plate 7 in the reinforced concrete lining 2. The end plate 7 should be embedded before pouring the reinforced concrete lining 2; wherein the reinforced concrete lining 2 includes a first reinforced concrete lining and a second reinforced concrete lining, and the end plate 7 is reserved with grouting holes and holes for pipe docking;

[0058] Place pipes layer by layer between the end plates 7 on both sides. The net distance between the pipes should not be less than 300mm, and backfill with plain concrete layer by layer. The order of concrete backfilling is from the middle of the pipe to both ends. After the construction reaches both ends, the two ends of the pipe are sealed and connected with the end plates 7 on the corresponding sides; high-pressure grouting concrete is poured from the grouting holes to ensure that the concrete backfill at the end plate 7 is dense and in close contact with the end plate 7; after the grouting is completed, the grouting holes are blocked with a newly installed small steel plate to ensure that the small steel plate and the end plate 7 are tightly fitted and reliably welded;

[0059] A steel lining 3 is constructed in the hard rock cavern, and the steel lining 3 is sealed and connected with the head plate 7.

[0060] When the length of the soft rock cavern is long, multiple sections of pipes can be assembled and connected in the soft rock cavern, pipes can be placed layer by layer in the middle of the head plates 7 on both sides, and plain concrete can be backfilled layer by layer, and high-pressure grouting can be used at the ends to make the backfill dense.

[0061] When the weak rock layer section is short, all the pipes can be placed at one time and welded to the head plate 7, and then high-pressure concrete can be poured through the grouting holes on the head plate 7 to make the concrete backfill dense.

[0062] As other possible implementation methods, the pipelines can also be fixed in layers before the head plate; or, the head plate adopts a block-type assembly structure, and the head plate and pipelines are placed cross-constructed. For example, the head plate is welded in blocks from bottom to top, and gravel is backfilled between the pipelines for preliminary backfilling to temporarily fix the pipelines. The construction is carried out layer by layer until the head plate seals all sections. Finally, after the head plate is welded and the head plate and the steel lining are sealed and connected, high-pressure grouting is performed into the inside of the two head plates to make the backfill dense.

[0063] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An artificial cavern structure for compressed air energy storage under local weak rock conditions, characterized in that: It includes a gas storage cavern, wherein the gas storage cavern includes a hard rock cavern and a soft rock cavern, and the cross-sectional excavation size of the hard rock cavern is greater than or equal to the cross-sectional excavation size of the soft rock cavern; The hard rock cavern is provided with a first reinforced concrete lining and a steel lining (3) in sequence from the surrounding rock side; The soft rock cavern is provided with a second reinforced concrete lining and at least one pipe, the cross section of the pipe being smaller than the cross section of the steel lining (3), the two ends of the pipe being connected to the steel lining (3) in the hard rock cavern on the corresponding side through a head plate (7), the pipe being in communication with the hard rock cavern, and the gap between the head plate (7), the pipe and the second reinforced concrete lining being filled with concrete (6).

2. The compressed air energy storage artificial cavern structure under local weak rock conditions according to claim 1 is characterized in that: The edge of the head plate (7) is arranged to extend beyond the end of the steel liner (3), and the head plate (7) and the steel liner (3) are connected in a T-shape.

3. The compressed air energy storage artificial cavern structure under local weak rock conditions according to claim 2 is characterized in that: The head plate (7) is of a flat plate structure, and the head plate (7) is arranged perpendicular to the wall of the gas storage cavern.

4. The compressed air energy storage artificial cavern structure under local weak rock conditions according to claim 2 is characterized in that: The first reinforced concrete lining and the second reinforced concrete lining are an integrally connected structure.

5. The compressed air energy storage artificial cavern structure under local weak rock conditions according to claim 1 is characterized in that: The axial direction of the plurality of pipelines is consistent with the axial direction of the steel lining (3).

6. The compressed air energy storage artificial cavern structure under local weak rock conditions according to claim 1 is characterized in that: The wall thickness of the pipeline is greater than or equal to the wall thickness of the steel lining (3).

7. The artificial cavern structure for compressed air energy storage under local weak rock conditions according to any one of claims 1 to 6, characterized in that: At least one of the pipelines comprises at least one first pipeline (4) and at least one second pipeline (5), wherein the diameter of the first pipeline (4) is larger than that of the second pipeline (5), and at least one of the first pipelines (4) is located below the soft rock formation cavern for manhole maintenance.

8. The artificial cavern structure for compressed air energy storage under local weak rock conditions according to claim 7 is characterized in that: The diameter of the first pipe (4) is greater than or equal to 3 m.

9. The compressed air energy storage artificial cavern structure under local weak rock conditions according to any one of claims 1 to 6, characterized in that: The number of the pipelines is at least two, and the net distance between the pipelines is greater than or equal to 300 mm.

10. The construction method of compressed air energy storage artificial cavern structure under local weak rock conditions according to any one of claims 1 to 9 is characterized in that: The following steps are involved: Excavating a gas storage cavern, wherein the gas storage cavern passes through a soft rock layer area, the gas storage cavern includes a hard rock cavern and a soft rock layer cavern, and the excavation section of the hard rock cavern is consistent with the excavation section of the soft rock layer cavern; Constructing a reinforced concrete lining (2), a head plate (7) and a pipeline, wherein the head plate (7) is pre-buried in the reinforced concrete lining (2), the reinforced concrete lining (2) comprises a first reinforced concrete lining and a second reinforced concrete lining, the head plate (7) is pre-reserved with grouting holes and holes for connecting the pipeline, and both ends of the pipeline are sealed and connected to the head plate (7) on the corresponding side; pouring concrete from the grouting hole (6), and sealing the grouting hole after the concrete pouring is completed; A steel lining (3) is constructed in the hard rock cave chamber, and the steel lining (3) is sealed and connected to the head plate (7).

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