Gas storage adaptive to high-pressure load and construction method thereof

Abstract

The invention belongs to the technical field of underground space development and energy and gas storage, and particularly relates to a gas storage adaptive to high-pressure load and a construction method thereof. The gas storage comprises a chamber built in a rock stratum, an anchor rod and an inner pulling rope, wherein the anchor rod is constructed to extend into the chamber from a surrounding rock on the outer side of the chamber to form anchor rod support. And the inner pulling rope extends inwards from the free end of the inner side of the anchor rod and is connected to one point in an intersecting manner, so that radial pulling force is provided for the chamber when the pressure in the chamber is larger than the pressure of surrounding rock. Through the arrangement of the inner pulling rope, upheaval and deformation of the upper terrain cannot occur when the pressure in the chamber is larger than the pressure of the surrounding rock, so that the energy storage upper limit of the chamber is improved, the requirement for geological conditions of building of the gas storage is lowered, and good application prospects are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of underground space development and energy storage and gas storage, and particularly relates to a gas storage cavern adapted to high-pressure loads and a construction method thereof. Background Art

[0002] Compressed air energy storage technology has the advantages of long operation cycle, large energy storage capacity, low construction cost, low site selection requirements, etc., and is a promising energy storage technology. Compressed air energy storage technology can cut peaks and fill valleys for the power grid, improve the unevenness problems in time and space at the power generation end, and effectively solve the disadvantages of unstable supply of new energy sources such as wind power, photovoltaic power, and biomass energy. It is an important energy storage technology for distributed integrated energy systems and can effectively promote the development of energy cleaning and low-carbonization.

[0003] The gas storage caverns of existing compressed air energy storage systems mainly adopt natural salt mines or the transformation of abandoned mine tunnels and steel storage tanks. Natural salt mines have good sealing performance and relatively low construction costs, but there are problems such as fewer site selections, unstable cavity formation, and the need for brine discharge treatment. Although abandoned mine tunnels can directly utilize existing underground resources, the sealing technology is difficult. Steel storage tanks have mature technology and flexible site selection, but the construction cost is high and the capacity is limited. Therefore, effectively utilizing underground space to overcome complex geological conditions is of great significance for the popularization and application of compressed air energy storage systems. Compared with natural salt mines and abandoned mine tunnels, hard rock formations are widely distributed, and it is of positive significance to construct artificial underground gas storage caverns in hard rock formations. However, during the operation of a compressed air energy storage power station, the internal air pressure is a high-frequency and high-pressure cyclic load. Therefore, the structural design of artificial gas storage caverns becomes an important prerequisite for the stable operation of compressed air energy storage systems and is of great significance for the large-scale application of compressed air energy storage technology.

[0004] Existing artificial gas storage caverns generally adopt the design concept of tunnels or chambers. Generally, the surrounding rock pressure of chambers is greater than the internal air pressure. Therefore, the tunnel structure design mainly focuses on bearing the surrounding rock pressure. There is a lack of design solutions for artificial gas storage caverns where the internal pressure is greater than the surrounding rock pressure. In current high-pressure gas storage caverns, due to the constraints of existing technologies and considerations of structural stability, the air pressure cannot exceed the surrounding rock pressure, which restricts the development of high-pressure gas storage caverns. Moreover, the existing designs of artificial gas storage caverns are all based on the elastic static strength theory, lacking reasonable consideration of dynamic loads and corresponding reinforcement schemes. Summary of the Invention

[0005] In view of some or all of the problems existing in the prior art, the present invention provides a gas storage cavern adapted to high-pressure loads and a construction method thereof.

[0006] According to a first aspect of the present invention, there is provided a gas storage cavern adapted to high-pressure loads.

[0007] The gas storage cavern adapted to high-pressure loads includes:

[0008] A chamber, constructed inside a rock formation;

[0009] A rock bolt, configured to extend from the outside of the chamber to the inside of the chamber to form a rock bolt support; and

[0010] An internal tension rope,

[0011] wherein, the internal tension rope is configured to extend inward from the inner free end of the rock bolt and intersect and connect at a point, so as to provide a radial tension force to the chamber when the pressure inside the chamber is greater than the surrounding rock pressure.

[0012] As an extension of the above technical solution, the present invention also provides the following embodiments:

[0013] A support structure configured to bear the surrounding rock pressure is provided inside the chamber, and the support structure is set up before the surrounding rock completes stress redistribution.

[0014] The support structure is a rock pillar formed by a part of the retained rock formation when the chamber is excavated.

[0015] The support structure is configured to be a cross shape including a longitudinally distributed structure.

[0016] The support structure is configured to be a linear shape with longitudinal distribution.

[0017] Shotcrete with mesh is provided on the surface of the support structure to play a role in reinforcement.

[0018] An anti-seepage layer formed by grouting operation in the loosening zone of the surrounding rock is provided outside the chamber.

[0019] The material used for the grouting operation is self-healing cement or polymer organic grouting material.

[0020] According to the second aspect of the present invention, a construction method for constructing a gas storage cavern adapted to high-pressure loads as described above is provided.

[0021] The construction method includes the following steps:

[0022] 1) Excavate the chamber at an appropriate depth in the rock formation;

[0023] 2) Perform rock bolt support operation on the chamber;

[0024] 3) Install the internal tension rope inside the chamber.

[0025] As an extension of the above technical solution, the present invention also provides the following embodiments:

[0026] Step 1) includes setting the support structure inside the chamber while or after excavating the chamber.

[0027] The advantages of the present invention compared with the prior art are as follows:

[0028] Firstly, by setting the inner tension ropes inside the chamber, a radially inward tension is provided for the chamber, thus solving the problem of the uplift or deformation of the upper stratum caused by the air pressure inside the chamber being greater than the surrounding rock pressure, enabling a higher gas storage pressure inside the chamber, reducing the requirements for geological conditions for building the gas storage reservoir, and having higher economy and safety;

[0029] Secondly, by pre-setting a support structure inside the chamber that can bear the surrounding rock pressure, the characteristics of short cycle load and incomplete stress redistribution are fully utilized, avoiding the deformation and failure problems faced by rigid linings such as reinforced concrete;

[0030] Thirdly, on the outside of the chamber, an anti-seepage layer with good plastic deformation characteristics is set by grouting the loosened area, thereby reducing the probability of problems such as gas leakage, water seepage, and deformation and failure of the gas storage reservoir. Description of the Drawings

[0031] Figure 1 It is a schematic structural diagram of the first embodiment of the gas storage reservoir adapted to high-pressure loads according to the present invention;

[0032] Figure 2 It is a schematic structural diagram of the second embodiment of the gas storage reservoir adapted to high-pressure loads according to the present invention;

[0033] Figure 3 It is a schematic structural diagram of the third embodiment of the gas storage reservoir adapted to high-pressure loads according to the present invention;

[0034] Figure 4 It is a schematic diagram of the internal structure of the chamber.

[0035] All the drawings in the present invention are schematic diagrams for explaining the structure and principle, and are not necessarily drawn according to the actual size and proportion.

[0036] The specific meanings of the reference numerals in the drawings are as follows:

[0037] 1. Chamber; 11. First area; 12. Second area; 13. Third area; 14. Fourth area; 2. Rock stratum; 21. Surrounding rock; 211. Loosened area; 212. Plastic strengthening area; 213. Elastic deformation area; 3. Anchor bolt; 4. Inner tension rope; 5. Support structure; 51. Rock pillar; 6. Anti-seepage layer; 100. Gas storage reservoir adapted to high-pressure loads. Detailed Embodiments

[0038] The embodiments of the present invention will be described in more detail below with reference to the accompanying drawings.

[0039] According to a first aspect of the present invention, a gas storage reservoir 100 adapted to high - pressure loads (hereinafter referred to as "gas storage reservoir 100") is provided.

[0040] Figures 1 to 3 FIG. is a schematic structural diagram of the gas storage reservoir 100 according to the present invention. As shown in the figure, the gas storage reservoir 100 includes a chamber 1 built inside a rock formation 2, rock bolts 3 configured to extend from the outside of the chamber 1 to the inside of the chamber 1, and internal tension ropes 4. A number of rock bolts 3 are distributed in the circumferential direction of a specific longitudinal section of the chamber 1, and the rock bolts 3 are provided to form rock - bolt support for the chamber 1. The number of internal tension ropes 4 is also several, and each internal tension rope 4 is configured to be connected to the inner free end of a certain rock bolt 3, and extends inward from the inner free end of the rock bolt 3 and intersects at a point, so as to provide a radial tension force to the chamber 1 when the pressure inside the chamber 1 is greater than the surrounding - rock pressure, thereby maintaining the pressure balance inside and outside the chamber 1, and further achieving the purpose of controlling the deformation of the upper strata. In addition, it should be noted that the surrounding rock 21 is the surrounding rock mass in the rock formation 2 whose stress state changes due to the excavation of the chamber 1, and belongs to a part of the rock formation 2, and the rock formation 2 belongs to a part of the strata.

[0041] During specific operations, after the gas storage reservoir 100 is constructed, the staff can introduce compressed air into the inside of the gas storage reservoir 100 to achieve the function of energy storage. And when the pressure of the compressed air inside the gas storage reservoir 100 is greater than the surrounding - rock pressure, due to the arrangement of the internal tension ropes 4, a radially inward tension force is provided to the chamber 1, thereby achieving the purpose of controlling the deformation of the upper strata.

[0042] Through this design, the problem of the uplift or deformation of the upper strata caused by the air pressure inside the chamber 1 being greater than the surrounding - rock pressure is solved, so that a higher gas storage pressure can be achieved inside the chamber 1, and the requirements for geological conditions for constructing the gas storage reservoir 100 are reduced, with higher economy and safety.

[0043] In an embodiment of the present invention, the internal tension rope 4 is made of a steel cable or a high - molecular - material rope.

[0044] In an embodiment of the present invention, the internal tension rope 4 is made of a steel cable, and all the steel cables are connected together by welding.

[0045] In an embodiment of the present invention, the internal tension rope 4 is made of a high - molecular - material rope, and all the high - molecular - material ropes are connected together by the method of anchoring with buckles and anchors.

[0046] Such as Figure 1 and Figure 2As shown, in an embodiment of the present invention, a support structure 5 configured to bear the surrounding rock pressure is provided inside the chamber 1, and the support structure 5 needs to be set up before the stress redistribution of the surrounding rock 21 is completed. When the gas storage reservoir 100 operates, the period of change in its internal air pressure load is daily, but it takes 30 to 100 days for the surrounding rock stress to reach stress equilibrium after redistribution, that is, it takes 30 to 100 days for the surrounding rock 21 to complete stress redistribution. Therefore, after the excavation of the chamber 1 is completed, there is no need to wait until the stress redistribution of the surrounding rock 21 is completed before imposing deformation constraints on it, because during the later operation of the gas storage reservoir 100, the internal air pressure in the chamber 1 is generally greater than the internal air pressure in the chamber 1 after the stress redistribution of the surrounding rock 21, that is, the surrounding rock 21 still needs to deform from the equilibrium state to redistribute stress again. Building the support structure 5 in the chamber 1 before the stress redistribution of the surrounding rock 21, compared with imposing deformation constraints on the surrounding rock 21 after the stress redistribution of the surrounding rock 21, enables the gas storage reservoir 100 to make full use of the characteristics of the short period of change in the internal air pressure load and the incomplete stress redistribution (incomplete deformation) of the surrounding rock 21, reduces the degree of deformation of the surrounding rock 21, and alleviates or avoids the deformation failure problems faced by rigid lining of the surrounding rock 21 with materials such as reinforced concrete. On this basis, since there is no need to overly consider the deformation failure problem of the chamber 1, the gas storage reservoir 100 can also reach a higher gas storage pressure, thereby increasing its energy storage capacity and improving the economy of the gas storage reservoir 100. In addition, it can also be seen that through this design, within a certain limit, the more frequent the change in the internal air pressure load of the gas storage reservoir 100, the higher the safety and stability of the gas storage reservoir 100, enabling the gas storage reservoir 100 to adapt to working conditions with a short load change period, so that the gas storage reservoir 100 can achieve flexible operation of energy storage and extraction, which helps to further improve economic benefits.

[0047] In an embodiment of the present invention, the support structure 5 is a rock pillar 51 formed by a part of the rock formation 2 that is retained when the chamber 1 is excavated. Through this design, the natural structure of the rock formation 2 is utilized to realize the support of the chamber 1, enabling the support structure 5 to achieve a closer connection with the surrounding rock 21, not being prone to damage and loosening, and not using other materials, having better economy.

[0048] In an embodiment of the present invention, the support structure 5 is made of materials such as steel pipes and reinforced concrete. Through this design, the dependence of building the support structure 5 on the quality of the rock formation 2 is reduced, making the applicable geological conditions of the gas storage reservoir 100 more extensive.

[0049] Such as Figure 1As shown, in an embodiment of the present invention, the support structure 5 is configured as a cross shape including a longitudinally distributed structure. Through this design, the chamber 1 can be supported by the support structure 5 in both the transverse and longitudinal directions, thereby enhancing the stability of the internal structure of the chamber 1.

[0050] As Figure 2 shown, in an embodiment of the present invention, according to the actual geological conditions of the gas storage reservoir 100, the support structure 5 is configured as a straight shape arranged longitudinally. Through this design, the chamber 1 is supported at the position where the compressive stress is the largest inside the chamber 1, while the supports in other directions are omitted. Thus, while effectively supporting the chamber 1, the internal volume of the chamber 1 is enlarged, and the energy storage capacity of the chamber 1 is increased.

[0051] In an embodiment of the present invention, shotcrete with wire mesh capable of playing a strengthening role is provided on the surface of the support structure 5. Through this design, the support structure 5 can be further strengthened, thereby enhancing the supporting effect of the support structure 5 on the chamber 1 and making the structure of the gas storage reservoir 100 more stable.

[0052] Preferably, for the purpose of enhancing the supporting effect of the support structure 5, the wire mesh in the shotcrete with wire mesh is welded into a ring and surrounds the support structure 5.

[0053] In an embodiment of the present invention, a plurality of support structures 5 are arranged along the axial direction of the chamber 1 inside the chamber 1.

[0054] In an embodiment of the present invention, an internal tension rope 4 is arranged between two adjacent support structures 5.

[0055] In an embodiment of the present invention, an anti-seepage layer 6 formed by grouting the loosened zone 211 in the surrounding rock 21 is provided outside the chamber 1. After the excavation of the chamber 1, due to the change of boundary conditions, stress redistribution will occur in the surrounding rock 21. The surrounding rock 21 is divided into a loosened zone 211, a plastic strengthening zone 212, and an elastic deformation zone 213 from the inside to the outside. Among them, the loosened zone 211 and the plastic strengthening zone 212 are collectively called the plastic deformation zone. The rock mass in the loosened zone 211 is cut by fissures, the rock mass strength is significantly weakened, and the anti-seepage performance is significantly reduced. By grouting the loosened zone 211 to form the anti-seepage layer 6, the rock mass in the loosened zone 211 and the grout together constitute an anti-seepage layer 6 with good plastic deformation ability. On the one hand, it enhances the gas leakage resistance and waterproofness of the chamber 1, and on the other hand, it can make the chamber 1 not be damaged while undergoing a certain degree of deformation, thereby improving the gas storage capacity of the chamber 1.

[0056] In one embodiment of the present invention, the grouting material used for forming the impermeable layer 6 is self-healing cement or polymer organic grouting material. Through this design, the good bonding ability of the above materials is utilized, so that the good plastic deformation ability and impermeability of the impermeable layer 6 can be better realized, ensuring the stability of the structure of the gas storage reservoir 100 and a high energy storage level.

[0057] In one embodiment of the present invention, the chamber 1 has an annular or vertically and horizontally connected transverse section.

[0058] In one embodiment of the present invention, the rock formation 2 is selected as a hard rock formation.

[0059] In a preferred embodiment of the present invention, in order to improve the construction safety and service life of the gas storage reservoir 100, the gas storage reservoir 100 is constructed in rock mass zones of Class I, Class II, and Class III.

[0060] In one embodiment of the present invention, the surrounding rock 2 is reinforced with plain shotcrete.

[0061] According to the gas storage reservoir 100 of the present invention, by arranging the internal tension ropes 4 inside the chamber 1, a radially inward tensile force is provided for the chamber 1, thus solving the problem of the uplift or deformation of the upper stratum caused by the air pressure inside the chamber 1 being greater than the surrounding rock pressure, enabling a higher gas storage pressure to be achieved inside the chamber 1, reducing the requirements for geological conditions in the construction of the gas storage reservoir, and having higher economy and safety. Secondly, by arranging a support structure 5 that can bear the surrounding rock pressure in advance inside the chamber 1, the characteristics of a short cyclic load period and incomplete stress redistribution are fully utilized, reducing or avoiding the deformation and failure problems faced by rigid linings such as reinforced concrete. Thirdly, an impermeable layer with good plastic deformation characteristics is arranged by grouting the loosened area on the outside of the chamber 1, thereby reducing the probability of problems such as gas leakage, water seepage, and deformation and failure of the gas storage reservoir 100.

[0062] According to the second aspect of the present invention, a method for constructing the gas storage reservoir 100 as described above is provided.

[0063] The method includes the following steps:

[0064] 1) Excavate the chamber 1 at an appropriate depth in the rock formation 2;

[0065] 2) Carry out bolt support operation on the chamber 1;

[0066] 3) Install the internal tension ropes 4 inside the chamber 1.

[0067] In one embodiment of the present invention, step 1) includes arranging the support structure 5 inside the chamber 1 simultaneously with or after the excavation of the chamber 1.

[0068] Preferably, in an embodiment of the present invention, in step 1), the support structure 5 is arranged in the chamber 1 by retaining the rock pillar 51 formed by a part of the rock formation 2 when excavating the chamber 1.

[0069] Preferably, as Figure 4 shown, in an embodiment of the present invention, step 1) is carried out in the following order: First, the first area 11 and the second area 12 located above the chamber 1 are excavated, and then the third area 13 and the fourth area 14 located below the chamber 1 are excavated to retain the rock pillar 51 at the middle position. This method can reduce the construction difficulty of the chamber 1 and can maintain the stability of the structures of the chamber 1 and the rock pillar 51 as much as possible.

[0070] In an embodiment of the present invention, the excavation depth of the chamber 1 is 100 - 800 m.

[0071] The method for constructing the gas storage reservoir 100 as described above according to the present invention can also achieve the technical effects achievable by the gas storage reservoir 100 as described above, which will not be elaborated here.

[0072] In the present invention, the specific meanings of "upper", "lower", "left", "right", "inner", "outer", "middle", "edge", etc. when expressing orientation terms are based on Figure 1 the drawing state of the gas storage reservoir 100 in

[0073] Finally, it should be noted that although the present invention has been described in detail with reference to the preferred embodiments, various improvements can be made to it and components therein can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present invention is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A gas storage reservoir adapted to high-pressure loads, comprising: A chamber (1) built inside a rock formation (2); Anchor bolts (3) configured to extend from the outside of the chamber (1) to the inside of the chamber (1) to form an anchor bolt support; And Inner tension ropes (4), wherein the inner tension ropes (4) are configured to extend inward from the free ends inside the anchor bolts (3) and intersect and connect at a point to provide a radial tensile force to the chamber (1) when the pressure inside the chamber (1) is greater than the surrounding rock pressure.

2. The gas storage reservoir adapted to high-pressure loads according to claim 1, characterized in that: A support structure (5) configured to bear the surrounding rock pressure is provided inside the chamber (1), and the support structure (5) is set up before the surrounding rock (21) completes stress redistribution.

3. The gas storage reservoir adapted to high-pressure loads according to claim 2, wherein: The support structure (5) is a rock pillar (51) formed by a part of the retained rock formation (2) when excavating the chamber (1).

4. The gas storage reservoir adapted to high-pressure loads according to claim 2 or 3, characterized in that: The support structure (5) is configured to be a cross shape including a longitudinally distributed structure.

5. The gas storage reservoir adapted to high-pressure loads according to claim 2 or 3, characterized in that: The support structure (5) is configured to be a longitudinally distributed linear shape.

6. The gas storage reservoir adapted to high-pressure loads according to claim 2 or 3, characterized in that: Shotcrete with mesh is provided on the surface of the support structure (5) to play a role in reinforcement.

7. The gas storage reservoir adapted to high-pressure loads according to claim 2, wherein: An anti-seepage layer (6) formed by grouting the loosened area (211) in the surrounding rock (21) is provided outside the chamber (1).

8. The gas storage reservoir adapted to high-pressure loads according to claim 7, wherein: The material used for the grouting operation is self-healing cement or polymer organic grouting material.

9. A method for constructing a gas storage reservoir adapted to high-pressure loads as claimed in any one of claims 2 to 8, comprising the following steps: 1) Excavate the chamber (1) at an appropriate depth in the rock formation (2); 2) Carry out an anchor bolt support operation on the chamber (1); 3) Install the inner tension ropes (4) inside the chamber (1).

10. The method for constructing a gas storage reservoir adapted to high-pressure loads according to claim 9, characterized in that: The step 1) includes setting the support structure (5) inside the chamber (1) simultaneously with or after excavating the chamber (1).

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