Compressed air energy storage chamber critical burial depth determination method considering group cave effect

Abstract

The invention discloses a method for determining the critical burial depth of a compressed air energy storage chamber considering the group cave effect, and relates to the technical field of energy storage, and the method comprises the following steps: S1, collecting the geological information of a current region according to the region where the chamber is located; s2, gas storage chamber construction parameters are determined; s3, the number of chambers is determined, and a fracture mode is determined according to the number of the chambers; and S4, according to the fracture mode, the geological information and the gas storage chamber construction parameters, the limit burial depth of the pressure storage underground chamber under the chamber group effect is calculated. According to the method, the chamber burial depth under the double-hole and multi-hole condition can be accurately solved, the calculation method is simple and easy to understand, the accuracy is high, the condition is comprehensively considered, and the method has very high engineering practical application value and good economic applicability.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and specifically to a method for determining the critical burial depth of a compressed air energy storage chamber considering the cavern effect. Background Technology

[0002] Compressed air energy storage (CAES) is a large-scale, long-term energy storage technology with advantages such as regulating peak and off-peak loads on the power grid and enhancing the absorption capacity of renewable energy. In various CAES systems, the use of underground artificial chambers as high-pressure air storage facilities has become a key area of ​​research and engineering application in recent years due to its excellent sealing performance, high pressure resistance, and relatively low construction cost.

[0003] Underground artificial chambers are typically constructed in stable rock masses using drill-and-blast methods or mechanical excavation. Their structural safety, airtightness, and economy are highly dependent on a well-designed burial depth. However, excessively shallow burial depth may lead to insufficient stress in the surrounding rock, making it difficult to maintain chamber stability and increasing the risk of deformation or even collapse. Furthermore, the complex geological conditions and well-developed fissures near the surface may make it difficult to meet the requirements for long-term high-pressure gas sealing. While excessive burial depth can improve the self-supporting capacity and sealing performance of the surrounding rock, it significantly increases construction difficulty and project costs, and may introduce adverse factors such as high ground stress and high ground temperature, affecting operational safety and maintenance convenience.

[0004] Therefore, scientifically and rationally determining the optimal burial depth of underground artificial chambers for compressed air energy storage is a crucial prerequisite for ensuring the safe, efficient, and economical operation of the system. This calculation requires comprehensive consideration of various factors, including regional geological conditions, rock mechanics parameters, internal pressure loads, geostress field characteristics, and engineering economics, to form a burial depth design criterion that balances structural stability, airtightness, and construction feasibility. This background provides an important foundation for subsequent theoretical analysis, numerical simulation, and engineering optimization of burial depth.

[0005] With the development of pressure-retained underground storage, the mainstream calculation methods for the burial depth of pressure-retained underground chambers currently include the oblique straight-line fracture surface method, the logarithmic spiral model method, and the straight-line fracture surface method. However, these methods all consider the limit burial depth of a single chamber under internal pressure and do not take into account the mutual influence between chamber groups. Therefore, these methods may result in inaccurate burial depth calculations when calculating the burial depth of chamber groups, leading to design deviations. Therefore, this invention provides a method for calculating the burial depth of large-diameter underground pressure-retained underground chambers that considers the effect of chamber groups. Summary of the Invention

[0006] To address the problem that existing methods for calculating the burial depth of compressed air storage chambers are not applicable to the calculation of the burial depth of underground chambers in compressed air storage under the influence of chamber groups, this invention proposes a method for determining the critical burial depth of compressed air storage chambers that considers the effect of multiple chamber groups.

[0007] The technical solution of this invention is: a method for determining the critical burial depth of a compressed air energy storage chamber considering the multi-cavity effect, comprising the following steps: S1. Collect geological information of the current area based on the location of the chamber; S2. Determine the construction parameters for the gas storage chamber; S3. Determine the number of chambers and determine the fracture mode based on the number of chambers; S4. Based on the fracture mode, geological information, and gas storage chamber construction parameters, calculate the ultimate burial depth of the underground chambers in the pressurized storage area under the chamber group effect.

[0008] Furthermore, in S1, the geological information for the current area includes the lateral pressure coefficient and rock mass cohesion.

[0009] Furthermore, in S2, the construction parameters of the gas storage chamber include the tunnel diameter, tunnel length, and the ratio of the chamber spacing to the tunnel diameter.

[0010] Furthermore, in S3, when the number of chambers is equal to 2, the first failure mode is selected; when the number of chambers is greater than 2, the second failure mode is selected.

[0011] Furthermore, the expression for the first breaking mode is: ; ; ; ; ; ; in, For the vertical burial depth safety factor, For the purpose of gas storage pressure, The weight of the overlying rock mass in the vertical direction of the chamber. This is the sum of the shear resistance forces under the first fracture mode. The rock mass is of high density. The chamber is vertically buried deep. The diameter of the tunnel. The length of the tunnel. This represents the first shear resistance under different fracture modes of the rock mass. This represents the secondary shear resistance under different rock mass failure modes. This represents the third shear resistance under different fracture modes of the rock mass. For rock mass cohesion, To create a cracked corner, The lateral pressure coefficient, For rock friction angle, This is the ratio of the distance between chambers to the diameter of the tunnel. The breaking angle.

[0012] Furthermore, the expression for the second breaking mode is: ; ; ; ; ; in, For the vertical burial depth safety factor, For the purpose of gas storage pressure, The weight of the overlying rock mass in the vertical direction of the chamber. It is the sum of the shear resistance forces under the second fracture mode. The rock mass is of high density. The chamber is vertically buried deep. The diameter of the tunnel. The length of the tunnel. This represents the secondary shear resistance under different rock mass failure modes. This represents the third shear resistance under different fracture modes of the rock mass. For rock mass cohesion, To create a cracked corner, The lateral pressure coefficient, For rock friction angle, This is the ratio of the distance between chambers to the diameter of the tunnel. The breaking angle.

[0013] Furthermore, cracking angle The expression is: ; in, The angle of friction between the rock and the rock. Rupture angle The expression is: .

[0014] Furthermore, the lateral pressure coefficient The expression is: ; in, The angle of friction between the rock and the rock.

[0015] Furthermore, the effect of gas storage pressure The expression is: ; in, The diameter of the tunnel. The length of the tunnel. This refers to the gas storage pressure.

[0016] The beneficial effects of this invention are: this invention can accurately solve the burial depth of the tunnel in the case of double-hole and multi-hole conditions. The calculation method is simple and easy to understand, highly accurate, and takes into account all situations. It has high practical engineering application value and good economic applicability. Attached Figure Description

[0017] Figure 1 A flowchart of a method for determining the critical burial depth of a compressed air energy storage chamber considering the multi-cavity effect; Figure 2 This is a schematic diagram of the structure of a single chamber as described in this invention; Figure 3 This is a schematic diagram of the first fracture mode in the case of a dual-chamber configuration described in this invention; Figure 4 This is a schematic diagram of the second fracture mode in the case of a dual-chamber configuration described in this invention. Detailed Implementation

[0018] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0019] like Figure 1 As shown, this invention provides a method for determining the critical burial depth of a compressed air energy storage chamber considering the multi-cavity effect, comprising the following steps: S1. Collect geological information of the current area based on the location of the chamber; S2. Determine the construction parameters for the gas storage chamber; S3. Determine the number of chambers and determine the fracture mode based on the number of chambers; S4. Based on the fracture mode, geological information, and gas storage chamber construction parameters, calculate the ultimate burial depth of the underground chambers in the pressurized storage area under the chamber group effect.

[0020] Under the single-chamber cone fracture mode, considering the mutual influence of double-chamber and multi-chamber systems, an innovative first fracture mode for double-chamber systems and a second fracture mode for three-chamber and above systems were proposed. The shear resistance of the rock mass under different fracture modes was solved, and the ultimate burial depth under the chamber group effect was solved by combining the self-weight of the rock mass.

[0021] In this embodiment of the invention, S1 includes the geological information of the current area, including the lateral pressure coefficient and the rock mass cohesion.

[0022] In this embodiment of the invention, in S2, the construction parameters of the gas storage chamber include the tunnel diameter, the tunnel length, and the ratio of the chamber spacing to the tunnel diameter.

[0023] In this embodiment of the invention, in step S3, when the number of chambers is equal to 2, the first fracture mode is selected; when the number of chambers is greater than 2, the second fracture mode is selected.

[0024] If the weight of the rock mass plus the shear resistance under different fracture modes is greater than the gas storage pressure multiplied by the safety factor at the specified burial depth, then the burial depth meets the requirements; otherwise, the burial depth should be adjusted.

[0025] In this embodiment of the invention, the expression for the first breaking mode is: ; ; ; ; ; ; in, For the vertical burial depth safety factor, For the purpose of gas storage pressure, The weight of the overlying rock mass in the vertical direction of the chamber. This is the sum of the shear resistance forces under the first fracture mode. The rock mass is of high density. The chamber is vertically buried deep. The diameter of the tunnel. The length of the tunnel. This represents the first shear resistance under different fracture modes of the rock mass. This represents the secondary shear resistance under different rock mass failure modes. This represents the third shear resistance under different fracture modes of the rock mass. For rock mass cohesion, To create a cracked corner, The lateral pressure coefficient, For rock friction angle, This is the ratio of the distance between chambers to the diameter of the tunnel. The breaking angle.

[0026] In this embodiment of the invention, the expression for the second breaking mode is: ; ; ; ; ; in, For the vertical burial depth safety factor, For the purpose of gas storage pressure, The weight of the overlying rock mass in the vertical direction of the chamber. It is the sum of the shear resistance forces under the second fracture mode. The rock mass is of high density. The chamber is vertically buried deep. The diameter of the tunnel. The length of the tunnel. This represents the secondary shear resistance under different rock mass failure modes. This represents the third shear resistance under different fracture modes of the rock mass. For rock mass cohesion, To create a cracked corner, The lateral pressure coefficient, For rock friction angle, This is the ratio of the distance between chambers to the diameter of the tunnel. The breaking angle.

[0027] In this embodiment of the invention, the crack angle... The expression is: ; in, The angle of friction between the rock and the rock. Rupture angle The expression is: .

[0028] In this embodiment of the invention, the lateral pressure coefficient The expression is: ; in, The angle of friction between the rock and the rock.

[0029] In this embodiment of the invention, the gas storage pressure plays a role. The expression is: ; in, The diameter of the tunnel. The length of the tunnel. This refers to the gas storage pressure.

[0030] The following description is based on specific embodiments.

[0031] Example 1

[0032] The relevant parameters of a certain compressed air energy storage underground gas storage facility are as follows: rock weight 26KN / m 3 The cohesion is 0.5 MPa, the internal friction angle is 45°, the length of a single chamber is 1000 m, the number of chambers is 2, the distance between chambers is 20 m, the vertical burial depth of the chamber is 100 m, the maximum gas storage pressure is 10 MPa, and the safety factor is 2.5.

[0033] The method for determining the minimum burial depth of underground compressed air storage facilities under the effect of chamber groups includes the following steps: Step 1: Determine the basic parameters of the rock strata. γ =26KN / m 3, =0.5MPa, φ =45°, k =1−sin φ =0.29.

[0034] Step 2: According to Figure 2 Determine the basic parameters of the chamber. p =10MPa, D =10m, L =1000m, number of chambers is 2 n =20 / 10=2.

[0035] Step 3: Determine that the number of chambers is greater than or equal to 2, at which point there will be a chamber group effect.

[0036] Step 4: When the number of chambers is equal to 2, the first selected fracture mode is used. The rock mass fracture path of the first selected fracture mode is as follows: Figure 3 As shown, according to the data in the embodiment, wherein, α =45°− φ / 2=22.5°, β =45°+ φ / 2=67.5° Step 5: Calculate according to the formula corresponding to the first selected breaking mode: Ensure fP ≤ G + F A Meets the requirements. fP =2.5× pDl =250000MN, of which the gravity component of the chamber G = γhDl =26000MN, F 1 = 96286MN F 2 = 57275MN, F 3 = 73472MN, therefore F A = F 1+ F 2+ F 3 = 96286 + 57275 + 73472 = 227033MN. Therefore... G + F A =26000+227033=253033MN≥ fP Therefore, the burial depth of the chamber group is 100m, which meets the resistance to uplift under the effect of the chamber group.

[0037] Example 2 The relevant parameters of a certain compressed air energy storage underground gas storage facility are as follows: rock weight 26KN / m 3The cohesion is 0.5 MPa, the internal friction angle is 45°, the length of a single chamber is 1000 m, the number of chambers is 3, the distance between chambers is 20 m, the vertical burial depth of the chamber is 100 m, the maximum gas storage pressure is 10 MPa, and the safety factor is 2.5.

[0038] The method for determining the minimum burial depth of underground compressed air storage facilities under the effect of chamber groups includes the following steps: Step 1: Determine the basic parameters of the rock strata. γ =26KN / m 3 , =0.5MPa, φ =45°, k =1−sin φ =0.29.

[0039] Step 2: According to Figure 2 Determine the basic parameters of the chamber. p =10MPa, D =10m, L =1000m, number of chambers is 2 n =20 / 10=2.

[0040] Step 3: Determine that the number of chambers is greater than or equal to 2, at which point there will be a chamber group effect.

[0041] Step 4: When the number of chambers is equal to 3, select the second failure mode. The rock mass failure path of the second failure mode is as follows: Figure 4 As shown, according to the data in the embodiment, wherein, α =45°− φ / 2=22.5°, β =45°+ φ / 2=67.5° Step 5: Calculate according to the formula corresponding to the second fracture mode: Ensure fP ≤ G + F B Meets the requirements. fP =2.5× pDl =250000MN, of which the gravity component of the chamber G = γhDl =26000MN, F B =2( F 2+ F 3), F 2 = 57275MN, F 3 = 73472MN, therefore F B =2( F 2+ F3) = 2 × (57275 + 73472) = 261494MN. Therefore... G + F A =26000+261494=287494MN≥ fP And much larger fP The safety factor of this chamber can reach 2.8 times, therefore the burial depth of this chamber group is 100m, which meets the anti-uplift requirements under the effect of the chamber group. However, this burial depth is relatively large and can be further optimized. After optimization, the burial depth of the chambers will be further simplified, which will help save costs.

[0042] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A method for determining the critical burial depth of a compressed air energy storage chamber considering the multi-cavity effect, characterized in that, Includes the following steps: S1. Collect geological information of the current area based on the location of the chamber; S2. Determine the construction parameters for the gas storage chamber; S3. Determine the number of chambers and determine the fracture mode based on the number of chambers; S4. Based on the fracture mode, geological information, and gas storage chamber construction parameters, calculate the ultimate burial depth of the underground chambers in the pressurized storage area under the chamber group effect.

2. The method for determining the critical burial depth of a compressed air energy storage chamber considering the multi-cavity effect according to claim 1, characterized in that, In S1, the geological information of the current area includes the lateral pressure coefficient and the rock mass cohesion.

3. The method for determining the critical burial depth of a compressed air energy storage chamber considering the multi-cavity effect according to claim 1, characterized in that, In S2, the construction parameters of the gas storage chamber include the tunnel diameter, tunnel length, and the ratio of the chamber spacing to the tunnel diameter.

4. The method for determining the critical burial depth of a compressed air energy storage chamber considering the multi-cavity effect according to claim 1, characterized in that, In S3, when the number of chambers is equal to 2, the first fracture mode is selected; when the number of chambers is greater than 2, the second fracture mode is selected.

5. The method for determining the critical burial depth of a compressed air energy storage chamber considering the multi-cavity effect according to claim 4, characterized in that, The expression for the first break mode is: ； ； ； ； ； ； in, For the vertical burial depth safety factor, For the purpose of gas storage pressure, The weight of the overlying rock mass in the vertical direction of the chamber. This is the sum of the shear resistance forces under the first fracture mode. The rock mass is of high density. The chamber is vertically buried deep. The diameter of the tunnel. The length of the tunnel. This represents the first shear resistance under different fracture modes of the rock mass. This represents the secondary shear resistance under different rock mass failure modes. This represents the third shear resistance under different fracture modes of the rock mass. For rock mass cohesion, To create a cracked corner, The lateral pressure coefficient, For rock friction angle, This is the ratio of the distance between chambers to the diameter of the tunnel. The breaking angle.

6. The method for determining the critical burial depth of a compressed air energy storage chamber considering the multi-cavity effect according to claim 4, characterized in that, The expression for the second breaking mode is: ； ； ； ； ； in, For the vertical burial depth safety factor, For the purpose of gas storage pressure, The weight of the overlying rock mass in the vertical direction of the chamber. It is the sum of the shear resistance forces under the second fracture mode. The rock mass is of high density. The chamber is vertically buried deep. The diameter of the tunnel. The length of the tunnel. This represents the secondary shear resistance under different rock mass failure modes. This represents the third shear resistance under different fracture modes of the rock mass. For rock mass cohesion, To create a cracked corner, The lateral pressure coefficient, For rock friction angle, This is the ratio of the distance between chambers to the diameter of the tunnel. The breaking angle.

7. The method for determining the critical burial depth of a compressed air energy storage chamber considering the multi-cavity effect according to claim 5, characterized in that, The crack initiation angle The expression is: ; in, The angle of friction between the rock and the rock. The breaking angle The expression is: .

8. The method for determining the critical burial depth of a compressed air energy storage chamber considering the multi-cavity effect according to claim 5, characterized in that, The lateral pressure coefficient The expression is: ; in, The angle of friction between the rock and the rock.

9. The method for determining the critical burial depth of a compressed air energy storage chamber considering the multi-cavity effect according to claim 5, characterized in that, The gas storage pressure The expression is: ; in, The diameter of the tunnel. The length of the tunnel. This refers to the gas storage pressure.

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