Underground high-pressure gas storage cavern lining concrete and preparation method thereof

Abstract

The present invention discloses an underground high-pressure gas storage cavern lining concrete and a preparation method thereof, wherein the lining concrete comprises the following raw materials in parts by weight: aggregate: 230-280 parts by weight; cement: 65-80 parts by weight; fly ash: 10-20 parts by weight; mineral powder: 10-15 parts by weight; compounding agent: 0.5-0.8 parts by weight; anti-cracking agent: 0.6-1.6 parts by weight; expansion agent: 6-8 parts by weight; fiber: 0.16-0.92 parts by weight. The underground high-pressure gas storage cavern lining concrete prepared by using the above raw materials in parts by weight has good compressive strength, fatigue resistance and load performance, and excellent crack resistance. During the operation of the underground gas storage, the lining concrete meets the requirements of high temperature (100°C-200°C) and air pressure circulation, and no through cracks are generated in the concrete. At the same time, the lining concrete has high air tightness, low cost, and convenient construction.

Description

Technical Field

[0001] The invention discloses an underground high-pressure gas storage cavern lining concrete and a preparation method thereof, and belongs to the technical field of building materials. Background Art

[0002] Compressed air energy storage technology is a large-scale energy storage technology with great potential. It can effectively support the peak-shaving needs of local power grids, promote the safe and stable operation of power systems, and alleviate the tight power supply situation caused by peak-to-valley differences. It has broad application value in the fields of power production, transportation and consumption.

[0003] Large-scale compressed gas energy storage power stations generally use underground gas storage as their gas storage equipment due to the large space required for energy storage. Hard rock formations have the advantages of good rock mass quality, high strength, and large deformation modulus, and are therefore considered candidate formations for underground gas storage construction research. Since joints and fissures are inevitable in natural rocks, they will greatly affect the air tightness of the gas storage and reduce its operating efficiency. Therefore, engineering measures are usually required to ensure the air tightness of the gas storage caverns, such as using composite linings or hydraulic conditions to ensure air tightness.

[0004] At present, composite linings mainly adopt steel, ordinary concrete, flexible polymer concrete and other solutions, but they are expensive, poor in economy, complicated in construction process, and cyclically changing pressure and temperature loads can easily cause cracks in the hard and brittle lining layer, thus leading to sealing failure. Summary of the invention

[0005] The purpose of this application is to provide an underground high-pressure gas storage cavern lining concrete and a preparation method thereof, so as to solve the technical problems of the composite lining composed of steel and ordinary concrete in the prior art, such as easy cracking, high cost and complicated construction process.

[0006] The first aspect of the present invention provides an underground high-pressure gas storage cavern lining concrete, comprising the following raw materials in parts by weight:

[0007] Aggregate: 230-280 parts by weight;

[0008] Cement: 65-80 parts by weight;

[0009] Fly ash: 10-20 parts by weight;

[0010] Mineral powder: 10-15 parts by weight;

[0011] Compounding agent: 0.5-0.8 parts by weight;

[0012] Anti-cracking agent: 0.6-1.6 parts by weight;

[0013] Expanding agent: 6-8 parts by weight;

[0014] Fiber: 0.16-0.92 parts by weight.

[0015] Preferably, the aggregate comprises:

[0016] Coarse aggregate: 120-150 parts by weight, the particle size of the coarse aggregate is 5-10 mm;

[0017] Fine aggregate: 110-130 parts by weight, the fineness modulus of the fine aggregate is greater than or equal to 2.7.

[0018] Preferably, the composite agent includes a polycarboxylate water reducer, a rheological agent and a collapse preventer;

[0019] The usage ratio of the polycarboxylic acid water-reducing agent, the rheological agent and the collapse-preventing agent is (18-24):(0.2-0.6):(1.9-4.5).

[0020] Preferably, the water-cement ratio of the lining concrete is 0.19-0.23.

[0021] Preferably, the expansion agent is a sulphoaluminate expansion agent.

[0022] Preferably, the fibers include cylindrical fibers and flat fibers;

[0023] The length of the cylindrical fiber is 6 to 12 mm;

[0024] The length of the flat fiber is 18 to 24 mm.

[0025] Preferably, the usage ratio of the cylindrical fibers to the flat fibers is (1-2):1.

[0026] A second aspect of the present invention provides a method for preparing underground high-pressure gas storage cavern lining concrete, comprising:

[0027] Step 1, weighing a composite agent and water by weight, adding the composite agent into the water and stirring evenly to obtain a first mixture;

[0028] Step 2, weighing aggregate, cement, fly ash, mineral powder, anti-cracking agent, expansion agent and fiber according to weight, and putting them into a stirring device, stirring them evenly to obtain a second mixture;

[0029] Step 3: Add 70% by weight of the first mixture into the second mixture for a first stirring, and then add the remaining 30% by weight of the first mixture into the mixture after the first stirring, and stir it for a second time to obtain underground high-pressure gas storage cavern lining concrete.

[0030] Preferably, the stirring time in step 2 is 30s to 1min.

[0031] Preferably, the stirring time of the first stirring in step 3 is 1 to 2 minutes, and the stirring time of the second stirring is 2 to 4 minutes.

[0032] Compared with the prior art, the underground high-pressure gas storage cavern lining concrete and the preparation method thereof of the present invention have the following beneficial effects:

[0033] (1) By adding fine aggregate and coarse aggregate of a certain grade, on the one hand, the mechanical properties of concrete can be improved, the amount of cement used can be reduced, and its hydration exothermic cracking can be reduced; on the other hand, the cost can be reduced, making it possible to use it on a large scale.

[0034] (2) The anti-cracking performance of the lining concrete of the present invention is improved by using the composite agent, anti-cracking agent, expansion agent and fiber in combination according to the set weight parts. Specifically, the composite agent ensures the workability and expansion of the gas storage lining concrete, ensures the density and uniformity of the concrete, adjusts the setting time of the concrete, and can appropriately reduce the water consumption to improve the mechanical properties of the concrete; the anti-cracking agent can further reduce the hydration heat of cement, delay the hydration reaction time, and avoid the internal and surface cracking of the concrete caused by the concentrated heat release of the hydration reaction; the expansion agent is a high-performance concrete expansion agent of a calcium sulfoaluminate-calcium oxide dual expansion source composite, which participates in the hydration reaction process in the concrete, produces a certain limited expansion, offsets the tensile stress caused by the shrinkage of the concrete, prevents the concrete structure from cracking due to excessive shrinkage, and effectively improves the crack resistance and waterproof performance of the concrete; by adding dispersed flat fibers and dispersed cylindrical fibers of different lengths, the generation and development of cracks in the concrete are inhibited, and the mechanical properties of the concrete are improved to a certain extent; the above components work synergistically, complement each other, and are indispensable to ensure that the lining concrete prepared by the present application will not have through cracks under cyclic pressure and temperature loads.

[0035] (3) The fibers used in the present invention are two fibers of different specifications, shapes or types, which improve the mechanical properties, fatigue resistance and crack resistance of the gas storage reservoir lining concrete, so that it can work and maintain a good working condition under the repeated effects of cyclic heat and force during the operation of compressed air energy storage, that is, it has excellent air tightness and crack resistance.

[0036] (4) The present invention uses mineral powder, fly ash and cement to fully exert their filling effect, refine the internal pore structure of concrete, improve the density, strength and durability of concrete, and reduce the air permeability coefficient of concrete. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of the present application.

[0038] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0039] In addition, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0040] A first aspect of an embodiment of the present invention provides an underground high-pressure gas storage cavern lining concrete, comprising the following raw materials in parts by weight:

[0041] Aggregate: 230-280 parts by weight; cement: 65-80 parts by weight; fly ash: 10-20 parts by weight; mineral powder: 10-15 parts by weight; compounding agent: 0.5-0.8 parts by weight; anti-cracking agent: 0.6-1.6 parts by weight; expansion agent: 6-8 parts by weight; fiber: 0.16-0.92 parts by weight.

[0042] In the embodiment of the present invention, the water-binder ratio of the lining concrete is 0.19-0.23, and therefore, the water used in the above raw materials in parts by weight is 19-23 parts.

[0043] The underground high-pressure gas storage cavern lining concrete prepared by using the above raw materials in parts by weight has good compressive strength and fatigue load resistance, and excellent crack resistance. During the operation of the underground gas storage, the lining concrete meets the requirements of high temperature (100°C to 200°C) and air pressure circulation, and no through cracks are generated in the concrete. At the same time, since the lining concrete of the present invention uses fly ash, mineral powder, composite agent, anti-cracking agent, expansion agent and fiber in combination, the internal structure of the concrete is reasonable and dense, thereby improving the air tightness of the lining concrete and making its air permeability coefficient K <1.4×10 -12 cm / s, during the operation of the compressed air energy storage power station, the daily air leakage of the gas storage cavern is guaranteed to be less than 0.5%. Compared with the steel lining, the lining concrete of the present application has a relatively low cost and is easy to construct, which reduces costs and improves construction efficiency.

[0044] Furthermore, the aggregate in the embodiment of the present invention includes 120-150 parts by weight of coarse aggregate and 110-130 parts by weight of fine aggregate. The coarse aggregate is rice stone, and rocks with low porosity such as granite or diorite are selected, and the overall particle size range of the coarse aggregate is 5-10 mm; the fine aggregate has a fineness modulus of not less than 2.7, the lithology is the same as that of the coarse aggregate, and the mud content of the natural sand is not more than 1%.

[0045] The reason why the embodiment of the present invention uses fine aggregate with a fineness modulus of not less than 2.7 is that if there is too much fine powder, the shrinkage of concrete will increase, which may easily cause concrete cracking; at the same time, the mud content of natural sand is not more than 1% mainly because the mud content of natural sand is large, the concrete requires a large amount of water, has poor plasticity, increases shrinkage, reduces concrete strength, and the structure is prone to cracking.

[0046] The embodiment of the present invention improves the mechanical properties of concrete by adding fine aggregate and coarse aggregate of a certain grade, reduces the amount of cement used and reduces its hydration exothermic cracking; and reduces the cost, so that it can be used on a large scale.

[0047] Because PO 52.5 cement has the advantages of fast setting and hardening, high early strength and late strength, good frost resistance, good carbonation resistance, and small shrinkage due to drying, the cement used in the embodiment of the present invention is PO52.5 cement.

[0048] Furthermore, the fly ash in the embodiment of the present invention is primary fly ash, which requires less water than secondary and tertiary fly ash, thereby ensuring that the amount of material is saved while the water-binder ratio remains unchanged.

[0049] The mineral powder of the embodiment of the present invention can be used as an admixture for concrete to improve or enhance the comprehensive performance of concrete. Its mechanism of action is that the mineral powder has a micro-aggregate effect, a micro-nucleus effect and a volcanic ash effect in concrete, and can also improve the impermeability of concrete, reduce hydration heat, and prevent temperature cracks.

[0050] The present invention uses mineral powder, fly ash and cement to compound, give full play to their filling effect, refine the internal pore structure of concrete, improve the density, strength and durability of concrete, and reduce the air permeability coefficient of concrete.

[0051] In order to ensure the workability of concrete, control the expansion of concrete, and improve the density of concrete, the composite agent used in the embodiment of the present invention includes admixtures such as polycarboxylic acid water reducer, rheological agent and collapse preventer; wherein the dosage ratio of polycarboxylic acid water reducer, rheological agent and collapse preventer is: (18-24): (0.2-0.6): (1.9-4.5).

[0052] The function of the polycarboxylate water-reducing agent in the embodiment of the present invention is to disperse cement particles, thereby releasing the encapsulated water molecules to allow them to participate in the flow, while effectively reducing the resistance between cement particles, changing the rheological process of concrete, and ensuring the uniformity of mixing of various raw materials.

[0053] The rheological agent in the embodiment of the present invention serves to increase the bridging effect between the adhesive and the aggregate, so that the cement mortar has suitable thixotropic properties, thereby driving the aggregate to flow together when the mortar flows, thereby avoiding concrete segregation.

[0054] The function of the slump-preventing agent in the embodiment of the present invention is to delay the hydration and coagulation of cement, so as to maintain the slump of concrete.

[0055] It can be seen that the collapse preventing agent used in the present invention can delay the hydration and coagulation of cement, thereby providing sufficient time for various raw materials to be mixed and bridged under the action of polycarboxylic acid water reducer and rheological agent, thereby improving the comprehensive properties of the prepared lining concrete, such as workability and density.

[0056] The main components of the anti-cracking agent in the embodiment of the present invention are hydroxy hydroxy acid ester, fine mineral powder, etc., which can delay the hydration reaction time of concrete, reduce the heat released by hydration, reduce the shrinkage cracking inside and on the surface of concrete, and to a certain extent promote the hydration of cement in the middle and late stages and improve the mechanical properties of concrete in the middle and late stages.

[0057] The expansion agent used in the embodiment of the present invention is a sulphoaluminate expansion agent, which can make the concrete have a certain expansion performance during the coagulation and hardening process, avoiding shrinkage cracking and surface cracking caused by water evaporation. Specifically, in the embodiment of the present invention, the expansion agent is a high-performance concrete expansion agent of a calcium sulphoaluminate-calcium oxide dual expansion source composite, which participates in the hydration reaction process in the concrete, produces a certain limited expansion, offsets the tensile stress generated by the shrinkage of the concrete, prevents the concrete structure from cracking due to excessive shrinkage, and effectively improves the crack resistance and waterproof performance of the concrete.

[0058] The fibers in the above raw materials include cylindrical fibers and flat fibers; wherein the length of the cylindrical fibers is 6 to 12 mm; the length of the flat fibers is 18 to 24 mm, and the ratio of the amount of cylindrical fibers to the flat fibers is (1 to 2): 1. The fibers used in the embodiment of the present invention are one or two of polyoxymethylene fibers (POM), polyvinyl alcohol fibers (PVA), and polypropylene fibers (PP), all of which are cylindrical or flat dispersed fibers. Dispersed fibers are distinct and can be quickly and evenly dispersed in concrete, giving full play to the bridging effect of the fibers, and will not agglomerate. On the one hand, shrinkage cracking inside and on the surface of the concrete can be avoided, and on the other hand, it is beneficial to improve the fatigue resistance of the concrete and avoid brittle failure. The length of the cylindrical fibers is 6 to 12 mm, and the length of the flat fibers is 18 to 24 mm. The main function of the short fibers is to improve the tensile strength, compressive strength and fatigue strength of the concrete, and the function of the long fibers is to prevent shrinkage cracking inside and on the surface of the concrete.

[0059] The present invention improves the crack resistance of lining concrete by combining composite agent, anti-cracking agent, expansion agent and fiber according to the set weight parts. Specifically, the composite agent ensures the workability and expansion degree of the gas storage lining concrete, adjusts the hydration reaction time, and avoids the phenomenon of concrete cracking caused by the concentrated heat release of cement hydration reaction; the anti-cracking agent can further reduce the heat of cement hydration to avoid concrete cracking caused by heat release; the expansion agent can make the concrete have a certain expansion performance during the coagulation and hardening process, avoiding shrinkage cracking and surface cracking caused by water evaporation; the fiber inhibits the generation and expansion of cracks. The above components work synergistically, complement each other, and are indispensable.

[0060] A second aspect of the present invention provides a method for preparing underground high-pressure gas storage cavern lining concrete, comprising:

[0061] Step 1, weighing the composite agent and water by weight, adding the composite agent into the water and stirring evenly to obtain a first mixture; in the embodiment of the present invention, the water and the composite agent are first stirred evenly, which is conducive to giving full play to the effect of the composite agent and shortening the stirring time of the concrete mixture.

[0062] Step 2, weighing aggregate, cement, fly ash, mineral powder, anti-cracking agent, expansion agent and fiber by weight, and putting them into a stirring device, stirring for 30 seconds to 1 minute until they are evenly mixed to obtain a second mixture;

[0063] Step 3, add 70% by weight of the first mixture into the second mixture for the first stirring, the stirring time of the first stirring is 1 to 2 minutes, until the stirring is uniform; then add the remaining 30% by weight of the first mixture into the mixture after the first stirring, stir for the second time, the stirring time of the second stirring is 2 to 4 minutes, and obtain the underground high-pressure gas storage cavern lining concrete. The embodiment of the present invention adopts a step-by-step feeding and stirring method. The purpose of the first stirring is to fully mix the raw materials and various admixtures to obtain sufficient time to play a role, so as to obtain an initial concrete mixture with uniform performance. The purpose of the second stirring is to change the state of the initial concrete mixture in a short time, which is conducive to controlling the workability of the concrete, improving the density of the concrete, and shortening the stirring time.

[0064] The present invention will be described in detail below with more specific embodiments.

[0065] Table 1 shows the raw material proportions and dosages (parts by weight) of four specific embodiments of the present invention. The fibers used in the four embodiments are cylindrical fibers with a length of 8 mm and flat fibers with a length of 20 mm.

[0066] Table 1 Ratio of raw materials

[0067]

[0068] The examples were subjected to a compressive strength test, an axial tensile test, a permeability test, and an air permeability coefficient test.

[0069] According to the "Testing Procedures for Hydraulic Concrete" DL / T 5150-2017, compressive strength tests, axial tensile tests and impermeability tests were carried out, and the impermeability grade was set to W12. The airtightness of concrete materials is characterized by the air permeability coefficient, which is tested by the bottom air intake method in the "Technical Specifications for Railway Gas Tunnels" TB 10120-2019, with the air pressure controlled at 0.6 MPa. The results are shown in Table 2.

[0070] Table 2 Test results

[0071]

[0072] It can be seen from Examples 1 to 4 that the 28d compressive strength of the high-pressure gas storage cavern concrete within the range of raw material dosage reaches 58 to 63 MPa, and the air permeability coefficient reaches 1.35×10 -12 cm / s or less, the 28d tensile strength is 5.4-6.9MPa, and both have reached the W12 anti-seepage grade.

[0073] The above four embodiments all meet the technical indicators of high-pressure gas storage cavern lining concrete: water-cement ratio 0.19-0.23, mixture expansion > 550mm, 28d compressive strength 40-65MPa, 28d tensile strength 5-7MPa, impermeability grade not less than W12, 28d air permeability coefficient K < 1.4×10 -12 cm / s.

[0074] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. An underground high-pressure gas storage cavern lining concrete, characterized in that: The invention comprises the following raw materials in parts by weight: Aggregate: 230~280 parts by weight; Cement: 65-80 parts by weight; Fly ash: 10-20 parts by weight; Mineral powder: 10-15 parts by weight; Compounding agent: 0.5~0.8 parts by weight; Anti-cracking agent: 0.6~1.6 parts by weight; Expanding agent: 6-8 parts by weight; Fiber: 0.16~0.92 parts by weight; The composite agent includes a polycarboxylic acid water reducer, a rheological agent and a collapse-preventing agent; The usage ratio of the polycarboxylic acid water-reducing agent, the rheological agent and the collapse-preventing agent is (18-24): (0.2-0.6): (1.9-4.5); The air permeability coefficient of the underground high-pressure gas storage cavern lining concrete is K<1.4×10 -12 cm / s; The fibers include cylindrical fibers and flat fibers; The length of the cylindrical fiber is 6 to 12 mm; The length of the flat fiber is 18-24 mm; The usage ratio of the cylindrical fibers to the flat fibers is (1~2):

1.

2. The underground high-pressure gas storage cavern lining concrete according to claim 1 is characterized in that: The aggregate comprises: Coarse aggregate: 120-150 parts by weight, the particle size of the coarse aggregate is 5-10 mm; Fine aggregate: 110-130 parts by weight, the fineness modulus of the fine aggregate is greater than or equal to 2.

7.

3. The underground high-pressure gas storage cavern lining concrete according to claim 1, characterized in that: The expansion agent is a sulphoaluminate expansion agent; The water-cement ratio of the lining concrete is 0.19-0.

23.

4. The underground high-pressure gas storage cavern lining concrete according to claim 1, characterized in that: The fiber is one or two of polyoxymethylene fiber, polyvinyl alcohol fiber and polypropylene fiber.

5. A method for preparing underground high-pressure gas storage cavern lining concrete based on any one of claims 1 to 4, characterized in that: include: Step 1, weighing a composite agent and water by weight, adding the composite agent into the water and stirring evenly to obtain a first mixture; Step 2, weighing aggregate, cement, fly ash, mineral powder, anti-cracking agent, expansion agent and fiber according to weight, and putting them into a stirring device, stirring them evenly to obtain a second mixture; Step 3: Add 70% by weight of the first mixture into the second mixture for a first stirring, and then add the remaining 30% by weight of the first mixture into the mixture after the first stirring, and stir it for a second time to obtain underground high-pressure gas storage cavern lining concrete.

6. The method for preparing underground high-pressure gas storage cavern lining concrete according to claim 5, characterized in that: The stirring time in step 2 is 30s to 1min.

7. The method for preparing underground high-pressure gas storage cavern lining concrete according to claim 5, characterized in that: The stirring time of the first stirring in step 3 is 1 to 2 minutes, and the stirring time of the second stirring is 2 to 4 minutes.

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