Controlled crack self-healing gas storage lining sealing structure and its construction method

Abstract

This invention discloses a controllable crack self-healing gas storage lining sealing structure and its construction method, comprising a sealing layer, a sliding layer, a segmented lining layer, and surrounding rock arranged sequentially from the inside out. The segmented lining layer is a concrete casting structure arranged in circumferential segments around the axial direction of the gas storage, with pre-reserved joints between adjacent segments. The pre-reserved joints are filled with a flexible sealant, and multiple polyurea microcapsules are dispersed within the segmented lining layer. When microcracks appear in the segmented lining structure, the polyurea microcapsules rupture due to their thermosensitive and pressure-sensitive characteristics, allowing the internal core material to wet the microcracks. A curing reaction occurs within the microcracks, repairing them, thereby effectively reducing the degree of cracking in the lining, preventing further expansion of microcracks, effectively extending the service life of the lining, and also reducing the risk of sink marks in the sealing layer caused by lining cracking, ensuring the sealing performance of the gas storage.

Description

Technical Field

[0001] This invention relates to the field of compressed air energy storage technology, and in particular to a controllable crack self-healing gas storage lining sealing structure and a construction method for a controllable crack self-healing gas storage lining sealing structure. Background Technology

[0002] Underground gas storage facilities are large-scale energy storage facilities in compressed air energy storage technology. Their main structures include a lining, a sealing layer, and surrounding rock. The lining needs to withstand periodic high internal air pressure and transmit force to the surrounding rock. The sealing layer prevents compressed air leakage to ensure the gas storage facility's sealing performance, while the surrounding rock needs to withstand the pressure within the chamber. In the operating environment of a gas storage facility, the air temperature inside can reach 80–100°C; due to heat conduction, the temperature inside the concrete lining can reach 60°C. Under the cyclic action of high temperature and high pressure, cracks inevitably form in the lining, reducing its structural integrity and ultimately causing damage to the lining and sealing layer. This leads to internal gas leakage, seriously affecting the safety of the gas storage facility and causing significant economic losses.

[0003] Currently, the main solutions to the problem of lining cracking in gas storage facilities include segmented lining and reinforced concrete lining. Segmented lining reduces the circumferential tensile stress on the lining by dividing it into several segments and setting pre-reserved joints; reinforced concrete structures increase the tensile strength of the lining by adding steel bars, thereby enhancing the load-bearing capacity of the lining.

[0004] For example, Chinese utility model patent document CN222363027U discloses a combined lining structure for underground gas storage. Its technical solution includes multiple lining sections and multiple buffer devices equal in number to the lining sections. The multiple lining sections are sequentially arranged along the circumference of the underground gas storage chamber on the inner wall of the chamber, with buffer joints between adjacent lining sections. Each buffer device is located at one buffer joint and includes a curved buffer element and two fixing elements. The two ends of the buffer element are sealed to two adjacent lining sections through the fixing elements. This utility model patent uses segmented lining and buffer joints between adjacent lining sections, combined with buffer devices. While this can transfer the gas pressure borne by the segmented lining to the surrounding rock during gas storage to prevent tensile cracking, it cannot completely prevent the formation of micro-cracks inside the lining. These micro-cracks gradually expand under the circulation of high internal gas pressure and eventually penetrate the lining to form macroscopic cracks. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a controllable crack self-healing gas storage lining sealing structure that can repair microcracks inside the lining to prevent microcracks from expanding into macrocracks.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a controllable crack self-healing gas storage lining sealing structure, comprising a sealing layer, a sliding layer, a segmented lining layer and surrounding rock arranged sequentially from the inside to the outside; the segmented lining layer is a concrete casting structure arranged in circumferential segments around the axial direction of the gas storage, and a reserved joint is provided between adjacent segments of the segmented lining layer; the reserved joint is filled with a flexible joint filler material, and multiple polyurea microcapsules are dispersed in the segmented lining layer.

[0007] As a further improvement to the above solution: the polyurea microcapsule consists of a shell and a core material filled inside the shell; the shell is made of a combination of polystyrene and paraffin, and the core material is a mixture of polyurea and a curing agent.

[0008] As a further improvement to the above solution: the sealant is butyl rubber.

[0009] As a further improvement to the above scheme, a reinforcement structure is also included, which is set within the segmented lining layer.

[0010] As a further improvement to the above scheme: the reinforcement structure includes circumferential reinforcement bars and radial reinforcement bars; each segment of the segmented lining layer is provided with at least one circumferential reinforcement bar, which extends circumferentially along the segmented lining layer and is fixed in the corresponding segment; each segment of the segmented lining layer is provided with multiple radial reinforcement bars, which extend radially along the gas storage tank and are evenly distributed circumferentially along the segmented lining layer.

[0011] As a further improvement to the above scheme: each segment of the segmented lining layer is provided with two circumferential reinforcing bars, which are arranged at radial intervals along the gas storage tank.

[0012] As a further improvement to the above scheme: the number of reserved seams is four, and the four reserved seams are distributed in a circumferential manner at a 90° interval; the width of the reserved seams is 20mm.

[0013] As a further improvement to the above scheme: the four reserved gaps are located at angles of 45°, 135°, 225° and 315° respectively, with the longitudinal centerline of the gas storage tank as the 0° reference line.

[0014] This invention also discloses a construction method for the above-mentioned controllable crack self-healing gas storage lining sealing structure, the construction method being carried out according to the following steps: S1-1. Erect molds and reinforce structures inside the cave, and set the positions for the reserved joints; S1-2. Prepare polyurea microcapsules, mix the raw materials of concrete and stir evenly, and add the prepared polyurea microcapsules into the pumped concrete. S1-3. Segmented pouring of the lining layer, followed by the application of joint filling material after the lining layer is demolded. S1-4. Concrete curing: After curing, the surface of the segmented lining layer is ground, and the sliding layer and sealing layer are constructed in sequence.

[0015] As a further improvement to the above scheme: In step S1-2, the preparation of polyurea microcapsules is carried out according to the following steps: S2-1. Prepare polyurea and curing agent, mix them in a ratio of 1:0.5, and stir evenly to form the core material. The core material accounts for 50% of the polyurea microcapsules. S2-2. Dissolve polystyrene in toluene or xylene to form a homogeneous solution. Heat paraffin to a molten state and add it to the solution, stirring until homogeneous. S2-3. Add the core material to the shell and add the emulsifier, then stir at high speed until an emulsion is formed; S2-4. Introduce the emulsion into deionized water and stir until the core material is encapsulated by the shell to form microcapsules; S2-5. After separating the microcapsules by centrifugation or filtration, wash the microcapsules with deionized water to remove unreacted substances, and then dry them to obtain the finished polyurea microcapsules. S2-6. Perform thermal responsiveness and pressure sensitivity tests on polyurea microcapsules.

[0016] The beneficial effects of this invention are as follows: By improving the sealing structure of the gas storage tank, this invention adopts a segmented lining structure and adds polyurea microcapsules. The polyurea microcapsules are dispersed inside the segmented lining structure. When microcracks appear in the segmented lining structure, the polyurea microcapsules break due to their own thermal and pressure-sensitive characteristics, allowing the internal core material to wet the microcracks. The microcracks are repaired by a curing reaction that occurs within the microcracks. This effectively reduces the degree of cracking in the lining, prevents further expansion of microcracks, and effectively extends the service life of the lining. At the same time, it also reduces the risk of sink marks caused by lining cracking in the sealing layer, ensuring the sealing performance of the gas storage tank. Attached Figure Description

[0017] Figure 1 A schematic diagram of the lining and sealing structure of a gas storage facility with controllable crack self-healing; Figure 2 This is a schematic diagram of the structure of polyurea microcapsules; Figure 3 This is a schematic diagram of the self-healing process of polyurea microcapsules under pressure. Figure 4 This is a schematic diagram of the heat-induced self-healing process of polyurea microcapsules.

[0018] The markings in the diagram are: 100-sealing layer, 200-sliding layer, 300-segmented lining layer, 310-reserved joint, 320-joint filler material, 330-polyurea microcapsule, 331-shell, 332-core material, 340-circumferential reinforcement, 350-radial reinforcement. Detailed Implementation

[0019] To facilitate understanding of the present invention, the invention will be further described below with reference to the accompanying drawings.

[0020] In the description of this invention, it should be noted that the terms "front", "rear", "left", "right", "up", "down", "inner", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0021] like Figure 1 As shown, the controllable crack self-healing gas storage lining sealing structure disclosed in this invention includes a sealing layer 100, a sliding layer 200, a segmented lining layer 300, and surrounding rock. In the radial direction of the gas storage, the sealing layer 100, the sliding layer 200, the segmented lining layer 300, and the surrounding rock are arranged sequentially from the inside to the outside, with the sealing layer 100 located in the innermost layer and the surrounding rock located in the outermost layer, forming the overall sealing structure of the gas storage.

[0022] Specifically, the sealing layer 100 in this invention primarily seals the high-pressure gas inside the gas storage tank; the sealing layer 100 can be made of flexible sealing materials such as butyl rubber or fiberglass. The sliding layer 200 is mainly used to coordinate the deformation between the sealing layer 100 and the segmented lining layer 300; the sliding layer 200 can be made of butyl rubber sealant or other flexible materials with strong adaptability to deformation, and its thickness is 1-2 mm. The surrounding rock should be Class III or above.

[0023] Specifically, this invention uses a segmented lining layer 300 to bear part of the internal pressure of the gas storage tank and serves as the base material for the sealing layer 100. For example... Figure 1As shown, the segmented lining layer 300 consists of multiple segmented structures, each segment being an arc-shaped concrete block arranged sequentially around the axial direction of the gas storage tank. Spacing is left between adjacent segments to form pre-reserved joints 310, which are filled with joint filler material 320. The joint filler material 320 is made of butyl rubber or other flexible materials and serves to coordinate deformation. By employing the segmented lining layer 300 with pre-reserved joints 310 and joint filler material 320 within them, the circumferential tensile stress borne by the lining can be reduced, thereby decreasing the probability of microcracks forming within the lining. Considering the stress conditions, the segmented lining layer 300 in this invention is composed of four segmented structures, and correspondingly, four reserved joints 310 are provided. The four reserved joints 310 are distributed in a circumferential manner with the longitudinal center line of the gas storage tank as the 0° reference line and at a 90° interval. That is, the distribution positions of the four reserved joints 310 correspond to angles of 45°, 135°, 225° and 315°, respectively; the joint width of the reserved joints 310 is set to 20mm.

[0024] To prevent microcracks generated within the lining from further expanding into macroscopic cracks, this invention incorporates multiple polyurea microcapsules 330 within the segmented lining layer 300. These polyurea microcapsules 330 are dispersed throughout the segmented lining layer 300. Specifically, as shown... Figure 2 As shown, the polyurea microcapsule 330 consists of a shell 331 and a core material 332 filled inside the shell 331. The shell 331 is made of a combination of polystyrene and paraffin wax, and the core material 332 is a mixture of polyurea and a curing agent. Because polystyrene has pressure-sensitive properties and paraffin wax has heat-sensitive properties, the shell 331 of the polyurea microcapsule 330 is simultaneously heat-sensitive and pressure-sensitive. This means that the shell 331 of the polyurea microcapsule 330 will rupture under certain temperature or pressure conditions, causing the polyurea and curing agent filling the shell 331 to leak out. Figure 3 As shown, when microcracks form within the segmented lining layer 300, under the cyclic action of high internal pressure, the microcracks will further expand. The internal structure of the segmented lining layer 300 contracts, exerting compressive force on the polyurea microcapsules 330. Due to their pressure-sensitive characteristics, the shell 331 of the polyurea microcapsules 330 ruptures. After the shell 331 ruptures, the polyurea and curing agent encapsulated inside overflows from the shell 331, wetting the concrete and flowing into the generated microcracks. A curing reaction occurs in the concrete pores and microcracks, thereby filling the concrete pores and microcracks and repairing the microcracks. Figure 4As shown, when the internal temperature of the segmented lining layer 300 rises, microcracks are generated inside the segmented lining layer 300 under the cyclic action of high internal pressure. When the internal temperature of the segmented lining layer 300 reaches the melting temperature of the shell 331, the shell 331 melts and breaks due to its heat-sensitive characteristics. The polyurea and curing agent wrapped inside the shell 331 overflow from the shell 331, wetting the concrete and flowing into the generated microcracks. A curing reaction occurs in the concrete pores and microcracks, thereby filling the concrete pores and microcracks and repairing the microcracks.

[0025] This invention, by adding polyurea microcapsules 330 with heat- and pressure-sensitive properties to the segmented lining layer 300, can repair microcracks by causing the shell 331 to break open when penetrated by microcracks. It can also repair microcracks elsewhere by causing the shell 331 to break open due to temperature increases, with the polyurea wetting the microcracks. Compared to epoxy microcapsules, polyurea microcapsules 330 have better flexibility, effectively preventing the repaired microcracks from cracking again under high temperature and pressure. This invention, by repairing microcracks generated within the segmented lining layer 300 using polyurea microcapsules 330, effectively prevents the microcracks from further expanding into macroscopic cracks, thereby significantly extending the service life of the segmented lining layer 300. Furthermore, by repairing microcracks, it reduces the risk of crevice formation in the sealing layer 100 due to lining cracking, effectively ensuring the long-term sealing performance of the gas storage facility.

[0026] Furthermore, such as Figure 1 As shown, to improve the strength of the segmented lining layer 300, the present invention also provides a reinforcing structure within the segmented lining layer 300. Specifically, the reinforcing structure consists of circumferential reinforcing bars 340 and radial reinforcing bars 350; both the circumferential reinforcing bars 340 and the radial reinforcing bars 350 are made of HRB400 grade steel. Each segment of the segmented lining layer 300 is provided with at least one circumferential reinforcing bar 340, which extends circumferentially along the segmented lining layer 300 and is fixed within the corresponding segment; each segment of the segmented lining layer 300 is provided with multiple radial reinforcing bars 350, which extend radially along the gas storage tank and are evenly distributed circumferentially along the segmented lining layer 300. The present invention enhances the tensile bearing capacity of the segmented lining layer 300 through circumferential reinforcing ribs 340, while enhancing the thermal conductivity of the segmented lining layer 300 through radial reinforcing ribs 350. The radial reinforcing ribs 350 also serve to connect and reinforce the circumferential reinforcing ribs 340. As a preferred embodiment, two circumferential reinforcing ribs 340 can be provided in each segment of the segmented lining layer 300, with the two circumferential reinforcing ribs 340 arranged radially at intervals along the gas storage tank.

[0027] This invention also discloses a construction method for the above-mentioned controllable crack self-healing gas storage lining sealing structure, which is carried out according to the following steps: S1-1. Erect the molds and reinforcement structures required for pouring the segmented lining layer 300 inside the tunnel, and set the position of the reserved joint 310.

[0028] S1-2. Prepare polyurea microcapsules 330. Prepare the raw materials of concrete according to the mass ratio and use machinery to mix the concrete evenly. At the same time, add the prepared polyurea microcapsules 330 to the pumped concrete. In step S1-2, the preparation of polyurea microcapsules 330 is carried out according to the following steps: S2-1. Prepare polyurea and curing agent, mix them in a ratio of 1:0.5, and stir evenly to form core material 332. Core material 332 accounts for 50% of polyurea microcapsules 330. S2-2. Dissolve 35% polystyrene in toluene or xylene to form a homogeneous solution. Heat 15% paraffin wax to a molten state and add it to the solution, stirring until homogeneous. S2-3. Add the core material 332 into the shell 331 and add 2% S emulsifier. Stir at high speed of 1000-3000 rpm until an emulsion is formed. S2-4. The emulsion is introduced into deionized water and stirred until the core material 332 is encapsulated by the shell 331 to form microcapsules. S2-5. After separating the microcapsules by centrifugation or filtration, wash the microcapsules with deionized water to remove unreacted substances, and then dry them to obtain the finished product of polyurea microcapsules 330. S2-6. Perform thermal responsiveness and pressure sensitivity tests on the polyurea microcapsules 330. During the thermal responsiveness test, heat the polyurea microcapsules 330 to 60°C and observe whether the shell 331 of the polyurea microcapsules 330 breaks to test whether its thermal responsiveness meets the standard. During the pressure sensitivity test, apply pressure to the polyurea microcapsules 330 and observe whether the shell 331 breaks to test whether its pressure sensitivity meets the standard. At the same time, microscopic observation of the polyurea microcapsules 330 is also required to detect whether the core material 332 is released when heated or compressed.

[0029] S1-3. Segmented pouring of the segmented lining layer 300. After the segmented lining layer 300 is demolded, the joint filling material 320 is applied.

[0030] S1-4. Curing the concrete for the specified time to ensure the strength and durability of the concrete lining; after curing, grinding the surface of the segmented lining layer 300, and then constructing the sliding layer 200 and the sealing layer 100 in sequence.

Claims

1. A construction method for a self-healing, crack-controllable gas storage lining sealing structure, characterized in that: The controllable crack self-healing gas storage lining sealing structure includes, from the inside out, a sealing layer (100), a sliding layer (200), a segmented lining layer (300), and surrounding rock; the segmented lining layer (300) is a concrete casting structure arranged in circumferential segments around the axial direction of the gas storage, and a reserved joint (310) is provided between adjacent segments of the segmented lining layer (300); the reserved joint (310) is filled with a flexible joint filler material (320), and multiple polyurea microcapsules (330) are dispersed in the segmented lining layer (300); the polyurea microcapsules (330) are composed of a shell (331) and a core material (332) filled inside the shell (331); the shell (331) is made of a combination of polystyrene and paraffin, and the core material (332) is a mixture of polyurea and a curing agent; the joint filler material (320) is butyl rubber. The construction method is carried out according to the following steps: S1-1. Erect molds and reinforce structures inside the cave, and set the position of the reserved joint (310); S1-2. Prepare polyurea microcapsules (330), mix the raw materials of concrete and stir evenly, and add the prepared polyurea microcapsules (330) into the pumped concrete. S1-3, pour the segmented lining layer (300) in sections, and apply the joint filling material (320) after the segmented lining layer (300) is demolded; S1-4. Concrete curing: After curing, the surface of the segmented lining layer (300) is ground, and the sliding layer (200) and sealing layer (100) are constructed in sequence. In steps S1-2, the preparation of polyurea microcapsules (330) is carried out according to the following steps: S2-1. Prepare polyurea and curing agent, mix them in a ratio of 1:0.5, and stir evenly to form the core material (332). The core material (332) accounts for 50% of the polyurea microcapsules (330). S2-2. Dissolve polystyrene in toluene or xylene to form a homogeneous solution. Heat paraffin to a molten state and add it to the solution, stirring until homogeneous. S2-3. Add the core material (332) into the shell (331) and add the emulsifier, and stir at high speed until an emulsion is formed; S2-4. The emulsion is introduced into deionized water and stirred until the core material (332) is encapsulated by the shell (331) to form microcapsules; S2-5. After separating the microcapsules by centrifugation or filtration, wash the microcapsules with deionized water to remove unreacted substances, and then dry them to obtain the finished polyurea microcapsules (330). S2-6. Thermal responsiveness and pressure sensitivity of polyurea microcapsules (330) were tested.

2. The construction method of the controllable crack self-healing gas storage lining sealing structure as described in claim 1, characterized in that: The controllable crack self-healing gas storage lining sealing structure also includes a reinforcement structure set within the segmented lining layer (300).

3. The construction method of the controllable crack self-healing gas storage lining sealing structure as described in claim 2, characterized in that: The reinforcement structure includes circumferential reinforcing bars (340) and radial reinforcing bars (350); each segment of the segmented lining layer (300) is provided with at least one circumferential reinforcing bar (340), the circumferential reinforcing bar (340) extends along the circumference of the segmented lining layer (300) and is fixed in the corresponding segment; each segment of the segmented lining layer (300) is provided with multiple radial reinforcing bars (350), the radial reinforcing bars (350) extend along the radial direction of the gas storage tank and are evenly distributed along the circumference of the segmented lining layer (300).

4. The construction method of the controllable crack self-healing gas storage lining sealing structure as described in claim 3, characterized in that: Each segment of the segmented lining layer (300) is provided with two circumferential reinforcing bars (340), which are arranged at radial intervals along the gas storage tank.

5. The construction method of the controllable crack self-healing gas storage lining sealing structure as described in claim 2, characterized in that: The number of reserved seams (310) is four, and the four reserved seams (310) are distributed in a circumferential manner at a 90° interval; the seam width of the reserved seams (310) is 20mm.

6. The construction method of the controllable crack self-healing gas storage lining sealing structure as described in claim 5, characterized in that: The four reserved gaps (310) are located at angles of 45°, 135°, 225° and 315° respectively, with the longitudinal centerline of the gas storage tank as the 0° reference line.

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