Gas storage cavern burial depth design method considering influence of group caverns, equipment and medium

Abstract

The invention relates to the technical field of compressed air energy storage underground cavern construction, in particular to a gas storage cavern burial depth design method and device considering the influence of group caverns and a medium. According to the method, optimization is carried out based on a rigid body cone model, a group cavity frustum model is obtained, the mutual influence between adjacent cavities is evaluated by introducing the center distance of the adjacent cavities, and whether the center distance of the cavities is in a group cavity influence area or not is judged; a burial depth calculation method in the prior art can be adopted to carry out stress analysis and calculate the burial depth based on the rigid body cone model; and when the center distance of adjacent caverns is in a group cavern influence area, carrying out stress analysis by adopting the group cavern frustum model provided by the invention, considering a fracture surface rock mass strength parameter, introducing cohesive force and internal friction angle action on the fracture surface, and re-establishing a stress balance equation to obtain a group cavern frustum model burial depth control equation, so that the burial depth is calculated.

Description

Technical Field

[0001] The present invention relates to the technical field of the construction of underground caverns for compressed air energy storage, in particular to a method, equipment and medium for designing the burial depth of gas storage caverns considering the influence of group caverns. Background Technique

[0002] Compressed air energy storage can effectively solve the problems of orderly consumption and storage of renewable energy electricity in the power grid system, realize peak shaving, valley filling, peak regulation and frequency modulation of the power grid, improve power supply efficiency, and ensure the safety and economy of the power grid. Compressed air energy storage technology mainly stores gas through underground artificial caverns. Artificial gas storage caverns have the advantages of convenient construction, safety and reliability, and flexible layout methods, and have become an important part of compressed air energy storage power stations. Artificial gas storage caverns are mostly arranged in moderately and slightly weathered rock formations, and at the same time, certain overburden requirements need to be met. The high-pressure gas inside the gas storage cavern transfers the pressure to the rock mass through the sealing structure and the lining structure. Since both sides and the lower part of the cavern are semi-infinite bodies and the thickness of the overlying rock mass is limited, under the action of the uplifting force of the high internal gas pressure, the overlying rock mass of the underground gas storage cavern may undergo uplift failure, which will also affect the stability, safety and tightness of the gas storage cavern. If the burial depth of the gas storage cavern is too large, there will be problems such as inconvenient cavern construction, increased length of construction auxiliary channels, and affecting the overall investment evaluation of the compressed air energy storage project. Therefore, in order to ensure the stability and economy of the gas storage cavern, a suitable cavern burial depth needs to be considered.

[0003] Since the current compressed air energy storage technology mostly stays in the theoretical research stage, there are few commercial operation cases. Regarding the design of cavern burial depth, in the prior art, in 2001, Brandshaug et al. proposed a rigid body cone model in the research topic of the anti-uplift safety evaluation of artificial caverns for compressed air energy storage. It is assumed that the rupture surface of the surrounding rock above the cavern is a cone with an angle of 30° to 45°. According to the anti-uplift principle that the weight of the conical rock mass is greater than the uplift pressure within the cavern body, an equilibrium relationship is established to solve the safe burial depth. This method does not consider the favorable influence of the cohesion and internal friction angle between rock masses when calculating the burial depth, nor does it consider the mutual influence between adjacent caverns when the caverns are arranged in parallel, making it difficult to directly apply the calculation results of this model to engineering. Later, some scholars such as Sun Guanhua optimized the rigid body cone failure model by considering the action of cohesion and internal friction angle on the failure surface, and established a burial depth control equation (referred to as the limit equilibrium method or the limit equilibrium theory model) based on the overlying rock mass pressure and the uplift force of the cavern using the limit equilibrium method, and thus deduced the safe burial depth of the cavern based on a certain iterative calculation method. Although this method considers a certain rock mass strength when calculating the burial depth, it still does not consider the mutual influence between adjacent caverns when the caverns are arranged in parallel, and the reliability is low.

[0004] Most of the existing buried depth calculation theories are optimized based on the (single - hole) rigid cone model, taking the single - hole model as the research object and not considering the influence of surrounding chambers. However, the layout of tunnel - type artificial gas storage chambers mostly adopts a loop - shaped annular chamber in the shape of a safety pin, with a large gas storage capacity. Limited by the land occupation requirements of the plane layout, the distance between different rings and between the two branches of the same ring is limited. Therefore, when calculating the buried depth of the chamber, the soil above the chamber needs to consider the mutual influence between adjacent chambers to make the calculation result of the buried depth more reasonable and reliable. Summary of the Invention

[0005] The purpose of the present invention is to provide a buried depth design method, device and medium for gas storage chambers considering the influence of group chambers, which can be applied to the safety buried depth design of group - chamber models, aiming at the problem that the mutual influence between adjacent chambers is not considered in the existing technology when calculating the buried depth of chambers.

[0006] In the first aspect, the present invention provides a buried depth design method for gas storage chambers considering the influence of group chambers, including the following steps:

[0007] Based on the rigid - body cone model, under the condition of group chambers, assume that the failure surface undergoes vertical punching failure in the stress intersection area of adjacent chambers, forming a group - chamber frustum model. The failure surface includes an inclined failure surface and a vertical failure surface.

[0008] Compare the center - to - center distance L between adjacent chambers and the limit boundary L 1 of the single - hole model to judge whether the distance between adjacent chambers exceeds the group - chamber influence area. If so, conduct a force analysis based on the single - hole rigid - body cone model and calculate the buried depth.

[0009] If not, then based on the group - chamber frustum model, by considering the action of cohesion and internal friction angle on the failure surface, establish a force - balance equation between the resistance force and the uplift force, obtain the buried - depth control equation of the group - chamber frustum model, and thus calculate the buried depth.

[0010] Among them, the limit boundary L 1 of the single - hole model is the horizontal distance between the center of the chamber and the ground failure boundary under the condition of the rigid - body cone model.

[0011] The present invention is optimized based on the rigid body cone model to obtain the group cavity frustum model, and by introducing the center distance between adjacent cavities and the limit boundary of the single cavity model, the mutual influence between adjacent cavities is evaluated to determine whether the center distance between cavities is within the influence area of the group cavities. During the calculation of the buried depth, the influence between adjacent cavities under the group cavity condition is considered: when the center distance between adjacent cavities exceeds the influence area of the group cavities, the buried depth calculation method in the prior art can be used to perform force analysis and calculate the buried depth based on the (single cavity) rigid body cone model; when the center distance between adjacent cavities is still within the influence area of the group cavities, the group cavity frustum model proposed by the present invention can be used for force analysis. By introducing the action of cohesion and internal friction angle on the rupture surface, the force balance equation between the resistance force and the uplift force is established, and the buried depth control equation of the group cavity frustum model is obtained, thereby calculating the buried depth. The buried depth design method provided by the present invention considers the influence between adjacent cavities under the group cavity condition and also considers the favorable influence of certain rock mass strength parameters on the rupture surface, such as cohesion and internal friction angle. The obtained buried depth calculation result is more reasonable and reliable.

[0012] As a preferred embodiment of the present invention, when judging whether the distance between adjacent cavities exceeds the influence area of the group cavities, it is judged whether L / 2 - L 1 ≥0 holds. If it holds, it indicates that the distance between adjacent cavities has exceeded the influence area of the group cavities. If it is not satisfied, it indicates that the distance between adjacent cavities is small and still within the influence area of the group cavities.

[0013] As a preferred embodiment of the present invention, when calculating the buried depth based on the rigid body cone model, the limit equilibrium method is used to establish the buried depth control equation f 1 , and taking the rupture angle β, the buried depth H, and the safety factor F s as the adjustment control variables (other related influence parameters are taken as fixed values according to the actual working conditions), the buried depth control equation under the single cavity condition is obtained as:

[0014] f 1 (β, H, F s ) = E a边侧 (β, H, F s ) - E a单中间 (H) = 0,

[0015] wherein, E a边侧 represents the vertical active force under the force balance condition of the side triangle, E a边侧 (β, H, F s ) represents that E a边侧 is related to the rupture angle β, the buried depth H, and the safety factor F s , E a单中间 represents the vertical active force under the force balance condition of the middle block under the single cavity condition, and E a单中间 (H) represents that E a单中间 is related to the buried depth H;

[0016] The steps for calculating the burial depth include:

[0017] S1: Obtain the initial cyclic set burial depth H when E a单中间 (H) = 0. 0 ;

[0018] S2: Initially set the safety factor F s to 1, and substitute the initial cyclic set burial depth H 0 into E a边侧 (β, H, F s ) to solve for the minimum value of E a边侧 . Set the rupture angle corresponding to the minimum value of E a边侧 as the initial cyclic rupture angle β 0 ;

[0019] S3: Substitute the initial cyclic rupture angle β s into the burial depth control equation f 0 (β, H, F 1 ) when F s = 1, and solve for the burial depth H 1 again;

[0020] S4: Compare whether the difference between H 0 and H 1 meets the accuracy requirement; if not, substitute H 1 back into E a边侧 (β, H, F s ) in step S2 to solve for the minimum value of E a边侧 . Reset the rupture angle corresponding to the minimum value of E a边侧 as the initial cyclic rupture angle β 0 , and repeatedly solve for the initial cyclic rupture angle β 0 and the burial depth H 1 until the difference between H 0 and H 1 meets the accuracy requirement; when the difference between H 0 and H 1 meets the accuracy requirement, determine the burial depth H 1 and the initial cyclic rupture angle β 0 ;

[0021] S5: Substitute the initial cyclic rupture angle β 1 corresponding to the burial depth H 0 that meets the accuracy requirement into the burial depth control equation f 1 (β, H, F s ) = 0, and reset the safety factor F s according to the design requirements, and solve for the final safety burial depth H.

[0022] In the case of establishing the single - hole buried - depth control equation by using the limit equilibrium method, by setting E a中间 (H)=0, the initial - cycle set buried - depth H 0 is obtained, and when the safety factor F s is 1, the rupture angle corresponding to the minimum value of Ea 边侧 is used as the initial - cycle rupture angle, and the model criterion is modified to the buried - depth precision control which is easier to intuitively grasp. In this way, through iterative calculation of the buried - depth control equation until the buried - depth meeting the precision requirements is obtained, then the safety buried - depth is recalculated in the buried - depth control equation according to the safety factor of the actual working condition and the rupture angle corresponding to the buried - depth meeting the precision requirements, as the final safety buried - depth under the corresponding working condition to adapt to the actual project. Among them, when the safety factor F s is 1, the obtained initial - cycle rupture angle meeting the requirements through iterative calculation is close to the rupture angle in the real situation and can be used to determine the position of the rupture surface.

[0023] In the process of solving the buried - depth of the traditional limit - equilibrium theory model, the rupture angle (i.e., the angle between the rupture surface and the horizontal plane) is used as the control target, that is, iterative calculation is carried out based on the initial buried - depth provided by the relevant specifications to obtain the rupture angle meeting the precision, and then the safe buried - depth of the cavern is deduced based on the rupture angle meeting the precision. The precision of the safe buried - depth obtained in this way is poor and is not conducive to buried - depth control. Therefore, compared with the buried - depth solving method of the traditional limit - equilibrium theory model, the buried - depth design method proposed by the present invention can further improve the buried - depth calculation precision, reduce the difference in the buried - depth calculation results, make the buried - depth design more intuitive, and is more conducive to buried - depth precision control.

[0024] As a preferred solution of the present invention, the steps of obtaining the buried - depth control equation of the group - hole frustum model include:

[0025] Dividing the group - hole frustum model into an intermediate block and side - trapezoidal blocks according to the position of the initiation point and the axis of the adjacent cavern; establishing force - balance equations with the intermediate block and the side - trapezoidal blocks as the research objects respectively, obtaining the active force E a群中间 on the vertical plane when taking the intermediate block as the research object and the active force E a边侧梯形 on the vertical plane when taking the side - trapezoidal block as the research object, so as to obtain the buried - depth control equation of the group - hole frustum model: f 2 =E a边侧梯形 -E a群中间 =0;

[0026] Among them, the initiation point is the intersection point of the rupture surface on the cross - section contour of the cavern.

[0027] When establishing the buried depth control equation of the group - hole frustum model in this solution, according to the position of the crack - initiation point and the mid - axis positions of two adjacent chambers, the group - hole frustum model is divided into regions by vertical punching in the cross - section, forming an intermediate block and side trapezoidal blocks. Considering the cohesive force and internal friction angle of the rupture surface, the force - balance equations between the resistance force and the uplifting force are established for the intermediate block and the side trapezoidal blocks respectively. Based on the corresponding force - balance equations, the equation relationship of the vertical active force \(E\) a中间 is derived with the intermediate block as the research object, and the equation relationship of the vertical active force \(E\) a边侧梯形 is derived with the side trapezoidal block as the research object; then, the active forces \(E\) a derived from the same vertical force - bearing surface are made equal and the difference is set to zero, thus obtaining the buried depth control equation \(f\) 2 of the group - hole frustum model.

[0028] As a preferred solution of the present invention, the \(E\) a边侧梯形 is derived under the condition that the side trapezoidal block is simplified to a side triangle. The simplification method is as follows: The equivalent slip surface is made by connecting the intersection point of the vertical rupture surface and the ground to the crack - initiation point. The rupture surface is equivalent to the equivalent slip surface, and the force of the side trapezoidal block is simplified to the force of the side triangular block according to the vector polygon criterion, so that the force - balance equation is established based on the side triangular block to obtain the \(E\) a边侧梯形 . By using the equivalent slip surface to equivalent the original rupture surface (oblique + vertical rupture surface), the force - analysis process is simplified and the calculation is convenient.

[0029] As a preferred solution of the present invention, when calculating the buried depth based on the buried depth control equation of the group - hole frustum model, first, the rupture angle \(\beta\) is obtained according to the buried depth control equation under single - hole conditions, and then the equivalent slip - surface inclination angle \(\omega\) is calculated according to the buried depth control equation of the group - hole frustum model; finally, the buried depth \(H\) is calculated according to the equivalent slip - surface inclination angle \(\omega\).

[0030] In a second aspect, the present invention also provides an electronic device. The electronic device includes a memory and at least one processor. The memory stores a computer program, and the processor is used to execute the computer program to implement the above - mentioned buried - depth design method.

[0031] In a third aspect, the present invention also provides a computer - readable storage medium. A computer program is stored on the computer - readable storage medium, and when the computer program is executed, the above - mentioned buried - depth design method is implemented.

[0032] In summary, due to the adoption of the above - mentioned technical solutions, the beneficial effects of the present invention are:

[0033] The buried depth design method provided by the present invention evaluates the mutual influence between adjacent caverns by introducing the center distance between adjacent caverns and the ultimate boundary of the single cavern model. During the calculation of the buried depth, the influence between adjacent caverns under the condition of a group of caverns is considered, and the favorable influence of the cohesion and internal friction angle on the rupture surface is also considered. The calculated result of the buried depth is more reasonable and reliable, providing an effective basis for the rationality evaluation of the plane layout scheme of tunnel-type artificial gas storage caverns. Description of the Drawings

[0034] Figure 1 It is a schematic diagram of the force on the cone failure model under the single cavern condition adopted in Embodiment 1;

[0035] Figure 2 It is a schematic diagram of the force analysis of the triangular block on the side of the single cavern model;

[0036] Figure 3 It is a schematic diagram of the force analysis of the middle block of the single cavern / group cavern model;

[0037] Figure 4 It is a schematic diagram of the division of the influence transmission area of the surrounding rock above the caverns under the group cavern condition;

[0038] Figure 5 It is a schematic diagram of the group cavern layout;

[0039] Figure 6 It is a schematic diagram of the force analysis of the modified group cavern frustum model in Embodiment 1;

[0040] Figure 7 It is a schematic diagram of the force analysis of the right trapezoidal block in the group cavern frustum model;

[0041] Figure 8 It is Figure 7 a schematic diagram of the force analysis with the introduction of an equivalent slip surface in

[0042] Figure 9 It is a calculation flow chart of the buried depth control equation of the group cavern frustum model in Embodiment 1;

[0043] Figure 10 It is a simulation effect diagram of the relationship between the active force and the rupture angle. Detailed Embodiments

[0044] The present invention will be described in detail below with reference to the drawings.

[0045] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0046] Embodiment 1

[0047] This embodiment proposes a design method for the burial depth of gas storage caverns considering the influence of group caverns. By introducing the parameter of the center distance between adjacent caverns to evaluate the mutual influence between adjacent caverns, a group cavern frustum model is further proposed based on the research results of scholars such as Sun Guanhua. And based on this group cavern frustum model, considering the action of cohesion and internal friction angle on the rupture surface, the force balance equation between the resistance force and the uplift force is re-established to obtain the burial depth control equation of the group cavern frustum model. The starting crack angle, rupture angle and the limit boundary parameters of the single cavern model are determined through the single cavern model, and then the safe burial depth under the group cavern model is calculated according to the burial depth control equation of the group cavern frustum model. When it is judged that the center distance between adjacent caverns exceeds the influence area of the group caverns, the existing single cavern model is used to calculate the burial depth; when it is judged that the center distance between adjacent caverns is within the influence area of the group caverns, it indicates that the center distance between adjacent caverns is small and the group cavern effect is relatively significant, and the group cavern frustum model is used for burial depth calculation. The specific technical solution includes three parts: the establishment of the single cavern burial depth control equation, the establishment of the group cavern burial depth control equation, and the model solution process.

[0048] I. Establish the single cavern burial depth control equation based on the limit equilibrium method.

[0049] By assuming that the rock mass undergoes anti-uplift failure along a fixed rupture angle and introducing the action of cohesion and internal friction angle on the rupture surface, the balance equation between the resistance force and the uplift force is established to obtain the burial depth control equation. The schematic diagram of the single cavern cone failure model is as Figure 1 shown. In the figure, G 1 is the gravity of the side triangular block (△CDE or △ABF), G 0 is the gravity of the middle block (ADEF), C s is the cohesion of the rupture surface, R s is the friction force of the rupture surface, β is the rupture angle, α is the starting crack angle, p u is the internal pressure in the cavern, R is the radius of the cavern, L 1 is the limit boundary width of the single cavern model. The establishment process of the single cavern burial depth control equation is as follows:

[0050] The first step is to establish the force balance equation of the side triangular block according to the schematic diagram of the force analysis of the side triangular block as Figure 2 shown, and deduce the active force E a on the vertical plane. In the figure, G 1 is the gravity of the side triangular block, C is the cohesion of the contact surface between the middle block and the side triangular block, E a is the acting force of the middle block, C s is the cohesion of the rupture surface between the side triangular block and the rock mass, R s is the friction force of the rupture surface between the side triangular block and the rock mass, β is the rupture angle, α is the starting crack angle, is the reduced internal friction angle of the rock mass, H is the burial depth of the cavern, h is the height from the starting crack point to the top of the cavern, L 0is the depth of the crack initiation point, L 0 =H+R-Rsinα.

[0051] Taking the side triangles as the research objects, the horizontal equilibrium equations are established respectively:

[0052]

[0053] The vertical equilibrium equation is:

[0054]

[0055] Where: C = c e L 0 ; (3)

[0056]

[0057]

[0058] By combining formulas (1) and (2) and eliminating Rs, we can obtain the vertical active force E derived based on the side triangle: a :

[0059]

[0060] Among them, c e is the rock mass cohesion, in kPa; L 0 is the burial depth at the crack initiation point, in m; β is the rupture angle, in degrees; F s is the safety factor; c s is the reduced rock mass cohesion, in kPa; γ is the rock mass density, in kN / m 3 ; is the friction angle in the rock mass; R is the radius of the cave, in m; λ is the friction reduction coefficient of the non-fracture surface.

[0061] The second step is to Figure 3 The schematic diagram of the force analysis of the middle block is shown in the figure. The force balance equation of the middle block is established and the main vertical force E is derived. a In the figure, G 0 is the weight of the middle block, C is the cohesion of the fracture surface between the middle block and the side triangle, E a is the force acting on the middle block, α is the crack initiation angle, is the friction angle in the rock mass, p u The pressure inside the cave.

[0062] Taking the middle block as the research object, the vertical equilibrium equation is established:

[0063] 2E a sinφ+G 0+2C = P; (9)

[0064] The value of E can be solved a :

[0065]

[0066] In the formula:

[0067]

[0068] α is the crack initiation angle, and the calculation formula is:

[0069]

[0070] Step 3: Establish the overburden control equation: The active force E derived from the same vertical stress-bearing surface a is equal, and the difference is zero. Thus, the overburden control equation of the single-hole model can be obtained.

[0071] To distinguish the vertical active force derived from the middle block and the vertical active force derived from the side triangle under the single-hole condition, in this paper, the vertical active force derived from the middle block under the single-hole condition is denoted as E a单中间 , and the vertical active force derived from the side triangle is denoted as E a边侧 . Then, the single-hole overburden control equation is:

[0072]

[0073] II. Establish the overburden control equation of the group holes:

[0074] Assume that the soil above each single chamber is damaged upward along a fixed oblique straight line. In the case where the compressed air energy storage chambers are arranged in parallel, as Figure 4 shown, when the horizontal net distance between adjacent chambers is small, after the upward lifting force of the chamber is transmitted to a certain area above the chamber, a stress superposition area will be formed at the position near the center of the adjacent chamber and close to the ground surface. Thus, the area around the chamber can be divided into a single-hole transmission area and a double-hole influence superposition area (or group-hole influence area). Further, as Figure 5 shown, the double-hole influence superposition area is simplified by punching at the mid-axis of the adjacent chamber, and the rupture surface of the adjacent chamber is corrected to a vertical punching rupture surface, such as the rupture surfaces GT and JU. Thus, a truncated cone rupture surface of the single-hole transmission area obliquely + the double-hole superposition area vertically is formed, such as the rupture surface OT-TG, and the group-hole truncated cone model is obtained. Figure 5 In it, H is the chamber overburden, h is the height from the crack initiation point to the chamber top, L 0 is the overburden of the crack initiation point, and L is the center distance between adjacent chambers. Among them, the crack initiation point is the intersection point of the rupture surface on the cross-sectional contour of the chamber.

[0075] Based on the grouped cavity frustum model, the above-mentioned grouped cavity frustum model can be further divided into an intermediate block and side trapezoidal blocks according to the position of the crack initiation point and the axis of the adjacent cavity. Cohesion and internal friction angle are introduced on the fracture surface of the grouped cavity frustum model to comprehensively consider the rock mass strength, and the limit equilibrium method is used to re-establish the balance equation between the resistance force and the uplift force, obtaining the buried depth control equation of the grouped cavity frustum model. For a single cavity, the schematic diagram of the overall force analysis of the grouped cavity frustum model is as shown in Figure 6 as follows. Figure 6 In the figure, G 1 is the gravity of the side trapezoidal block, G 0 is the gravity of the intermediate block, C s1 , C s2 are the cohesion on the vertical fracture surface and the inclined fracture surface respectively, R s1 , R s2 are the frictional forces on the vertical fracture surface and the inclined fracture surface respectively, β is the fracture angle, α is the crack initiation angle, and p u is the internal pressure in the cavity.

[0076] The specific establishment process of the buried depth control equation of the grouped cavity frustum model is as follows:

[0077] First step, establish the force balance equation of the side trapezoidal block and derive the active force E a on the vertical plane.

[0078] As shown in Figure 7 is the schematic diagram of the force analysis of the right trapezoidal block. In Figure 7 , G 1 is the gravity of the side trapezoidal block, C is the cohesion on the contact surface between the side trapezoidal block and the intermediate block, E a is the acting force of the intermediate block on the side trapezoidal block, C s1 , C s2 are the cohesion on the vertical fracture surface and the inclined fracture surface respectively, R s1 , R s2 are the frictional forces on the vertical fracture surface and the inclined fracture surface respectively, β is the fracture angle, α is the crack initiation angle, is the reduced internal friction angle of the rock mass, φ is the angle between the active force E a on the non-fracture surface and the horizontal plane, H is the buried depth of the cavity, h is the height from the crack initiation point to the top of the cavity, and L 0 is the buried depth of the crack initiation point.

[0079] In this embodiment, in order to simplify the number of unknowns, as shown in Figure 8 , based on the vector polygon rule of force, an equivalent slip surface is introduced to equivalent the force on the original failure surface, and the horizontal direction balance equation and the vertical direction balance equation are established respectively with the simplified side triangular block as the research object, so as to derive the active force E a on the vertical plane under the force balance condition of the side trapezoidal block.. In Figure 8 , G 1 is the gravity of the trapezoidal block on the primary side, C is the cohesion of the contact surface between the trapezoidal block on the side and the middle block, E a is the acting force of the middle block on the trapezoidal block on the side, C s is the cohesion on the equivalent slip surface, R s is the friction force on the equivalent slip surface, β is the rupture angle (i.e., the dip angle of the rupture surface), α is the initiation angle (i.e., the angle between the line connecting the initiation point to the center of the cavern and the horizontal plane), ω is the dip angle of the equivalent slip surface, is the reduced internal friction angle of the rock mass, H is the buried depth of the cavern, h is the height from the initiation point to the roof of the cavern, L 0 is the buried depth of the initiation point, h 1 is the height of the inclined cone failure surface, h 2 is the height of the vertical failure surface, φ is the angle between the active force Ea on the non-rupture surface and the horizontal plane, L j is the horizontal distance from the initiation point to the ground rupture boundary.

[0080] Among them, the horizontal direction equilibrium equation:

[0081]

[0082] The vertical direction equilibrium equation:

[0083]

[0084] In the formula:

[0085] C = c e L 0 ; (17)

[0086]

[0087] L j = L / 2 - Rcosα; (22)

[0088] L 0 = tanωL j ; (23)

[0089] By simultaneously solving formulas (15) and (16) to eliminate Rs, the vertical active force E a derived based on the trapezoidal block on the side can be obtained:

[0090]

[0091] Among them, c e is the cohesion of the rock mass, with the unit of kPa; L 0 is the buried depth at the initiation point, with the unit of m; c s is the reduced cohesion of the rock mass, with the unit of kPa; Lj is the horizontal distance from the crack initiation point to the ground rupture boundary, with the unit of m; L is the center-to-center distance of adjacent chambers, with the unit of m; β is the rupture angle, with the unit of °; Fs is the safety factor; c s is the reduced cohesive force of the rock mass, with the unit of kPa; γ is the unit weight of the rock mass, with the unit of kN / m 3 ; is the internal friction angle of the rock mass; R is the radius of the chamber, with the unit of m; λ is the reduction coefficient of the frictional resistance of the non-rupture surface.

[0092] In the second step, according to the force analysis schematic diagram of the middle block shown as Figure 3 , establish the force equilibrium equation of the middle block in the group of cavities model, and derive the active force E a .

[0093] Establish the vertical equilibrium equation with the middle block as the research object:

[0094] 2E a sinφ + G 0 + 2C = P; (25)

[0095] E can be solved as a :

[0096]

[0097] In the formula:

[0098]

[0099] In the third step, establish the buried depth control equation under the group of cavities frustum model: The active forces E a derived from the same vertical force-bearing surface are equal, and the difference is zero. Thus, the buried depth control equation under the group of cavities frustum model can be obtained.

[0100] To distinguish the active force on the vertical plane derived from the middle block and the active force on the vertical plane derived from the side trapezoidal block under the group of cavities frustum model, in this paper, the active force on the vertical plane derived from the middle block under the group of cavities frustum model is denoted as E a群中间 , and the active force on the vertical plane derived from the side trapezoidal block is denoted as E a边侧梯形 . Then, the buried depth control equation under the group of cavities frustum model can be expressed as:

[0101]

[0102] In the fourth step, according to the Figure 8 geometric relationship in, derive the safe buried depth of the group of cavities correction model:

[0103] H = tanωL j-R + Rsinα. (30)

[0104] III. Use the model solution process shown as Figure 9 to calculate the safe burial depth of the cavern under the condition of group caverns. Specifically, it includes the following steps:

[0105] The first step is to determine the design parameters: the cavern diameter R (unit: m), the rock unit weight γ (unit: kN / m 3 ), the design internal pressure p u (unit: kPa), the coefficient of lateral earth pressure k, the surrounding rock category, the cohesion c e (unit: kPa; note: the cohesion input here is the cohesion parameter provided by geological exploration), the internal friction angle (unit: °), the center distance L between adjacent caverns (unit: m), and the initial safety factor is set as Fs = 1.

[0106] The second step is to determine the initial burial depth H 0 : Let the formula (10) be equal to 0 and solve for the initial cyclic setting burial depth H 0 .

[0107] The third step is to determine the initial rupture angle β 0 : Substitute the H 0 calculated in the second step into the formula (8), and by solving the minimum value of E a边侧 , set the rupture angle corresponding to the minimum value of E a边侧 as the initial cyclic rupture angle β 0 .

[0108] The fourth step is to recalculate the burial depth: Substitute the rupture angle β 0 obtained in the third step into the burial depth control equation (14) and solve for the burial depth H 1 again.

[0109] The fifth step is to judge the rationality of the solved burial depth and further correct the result: Compare the difference between H 0 and H 1 to see if it meets the accuracy requirements. If not, substitute the H 1 obtained in the fourth step back into the third step and cycle to solve for the rupture angle β 0 and the burial depth H 1 until the burial depth H 1 that meets the accuracy requirements is obtained.

[0110] The sixth step is to solve for the burial depth H and rupture angle β of the single - cavern model: Substitute the rupture angle β 0 corresponding to the burial depth that finally meets the accuracy requirements in the fifth step into the formula (14), and reset the safety factor F s value according to the project requirements to obtain the safe burial depth H and rupture angle β of the single - cavern model.

[0111] Step 7: Solve for the limit boundary L of the single-hole model 1 :

[0112] Among them, the limit boundary L of the single-hole model 1 is the horizontal distance from the center of the cavity to the ground rupture boundary under the condition of the rigid body cone model, and is obtained by solving the single-hole model.

[0113] Step 8: Criterion for the multi-hole model: According to the center distance L between adjacent cavities, judge whether L / 2 - L 1 ≥0 holds. If it holds, it indicates that the distance between adjacent cavities has exceeded the influence area of the multi-hole, and the burial depth should be calculated using the single-hole cone failure model, that is, the burial depth result obtained in Step 6; if it is not satisfied, it indicates that the distance between adjacent cavities is small and still within the influence area of the multi-hole, and the next step should be entered to correct the burial depth using the multi-hole frustum cone model.

[0114] Step 9: Determine the design parameters of the multi-hole model: cavity diameter R, rock unit weight γ, design internal pressure p u , initiation angle α, rupture angle β, cohesion c e , internal friction angle center distance L between adjacent cavities, limit boundary L of the single-hole model 1 , safety factor Fs.

[0115] Step 10: Determine the equivalent slip surface inclination angle ω of the multi-hole model: In the multi-hole frustum cone model burial depth control equation (29), the initiation angle α and rupture angle β can be determined by the single-hole model. Therefore, the variable in equation (29) is unique (equivalent slip surface inclination angle ω) and can be solved. Let equation (29) be equal to 0, and the equivalent slip surface inclination angle ω of the multi-hole model can be solved.

[0116] Step 11: Determine the calculated burial depth of the multi-hole model: Substitute the equivalent slip surface inclination angle ω of the multi-hole model calculated in Step 10 into equation (30) to obtain the burial depth H, and this burial depth can be regarded as the safety burial depth under the condition of the multi-hole correction model.

[0117] Step 12: Output the final safety burial depth H.

[0118] IV. Example of the limit equilibrium multi-hole calculation model

[0119] Taking a compressed air energy storage peak shaving power station project as an example, this project adopts an advanced compressed air energy storage technology route. The gas storage cavern uses newly excavated underground artificial cavities, with a designed volume of 875,000 m 3 , a designed cavity diameter of 12 m, and a maximum gas storage pressure of 10.1 MPa. The calculation steps for the safe burial depth of the cavities under the multi-hole condition are as follows:

[0120] S1. Determine the design parameters: cavity diameter R = 6 m, rock unit weight γ = 25 kN / m 3 , design internal pressure p u= 10100 kPa, the coefficient of lateral earth pressure k = 1.3, the surrounding rock category is Class III, the cohesion c e = 1700 kPa, the internal friction angle The center distance L between adjacent caverns is 24 m, and the initial safety factor Fs is set to 1.

[0121] S2. Determine the initial design burial depth H 0 : Substituting k into formula (13), the crack initiation angle α = 38.28°. For Class III surrounding rock, the value of λ is 0.9. Then:

[0122] C = c e L 0 = 1700×(H 0 + 6 - 6sin38.28) = 1700H 0 + 3881.05,

[0123]

[0124] P = 2Rp u cosα = 2×6×10100×cos38.28 = 95141.1,

[0125]

[0126] Substitute the above results into formula (10) and set formula (10) equal to 0, that is:

[0127]

[0128] The initial cyclic design burial depth H can be solved 0 = 24 m.

[0129] S3. Determine the initial design fracture angle β 0 : According to the H obtained from the previous step's calculation 0 Get:

[0130] L 0 = 24 + 6 - 6sin38.28 = 26.29,

[0131] C = c e L 0 = 1700×26.29 = 44681.05,

[0132]

[0133] Substitute the above formula into formula (8) to obtain the vertical plane active force E under the condition of the force balance of the side triangle a边侧 :

[0134]

[0135] It can be seen from the above formula that E a边侧 is an equation about the only variable β. Plot the β-E a relationship curve, as Figure 10 shown.

[0136] By further solving the minimum value of Ea through the matlab mathematical toolbox, the initial cyclic rupture angle β 0 = 70.6° can be obtained.

[0137] S4. Recalculate the burial depth: Substitute the obtained initial cyclic rupture angle β 0 into each parameter to get:[[]]

[0138] L 0 = H 0 + 6 - 6sin38.28 = H 1 - 2.28,

[0139] C = c e L 0 = 1700(H 1 - 2.28),

[0140]

[0141] P = 2Rp u cosα = 95141.1,

[0142]

[0143] The burial depth control equation can be expressed as:

[0144]

[0145] The burial depth H can be solved through the burial depth control equation 1 = 23.96m.

[0146] S5. Judge the rationality of the solved burial depth and further correct the result: Compare the difference between H 0 and H 1 to get |H 0 - H 1 | = 24 - 23.96 = 0.04m. Assume that this difference meets the accuracy requirements of this project and proceed to the next step.

[0147] S6. Solve the final burial depth H: Substitute the above-mentioned rupture angle β 0 that finally meets the accuracy requirements into formula (14). According to the actual working conditions of the project, set the safety factor F s = 1.5 to get:

[0148]

[0149] By re-solving the single-hole buried depth control equation, the final buried depth of the single hole is obtained as H = 32.39 m, and the fracture angle is 70.6°.

[0150] S7. Solve the limit boundary L of the single-hole model 1 :

[0151]

[0152] S8. Criterion for the multi-hole model: Since L / 2 - L 1 = 12 - 15.93 < 0, it indicates that the distance between adjacent chambers is small and still within the influence area of the multi-hole. Therefore, the multi-hole frustum model should be used for buried depth correction.

[0153] S9. Determine the design parameters of the multi-hole model: The hole diameter R = 6 m, the rock unit weight γ = 25 kN / m 3 , the designed internal pressure p u = 10100 kPa, the initiation angle α = 38.28°, the fracture angle β = 70.6°, the cohesion c e = 1700 kPa, the internal friction angle The center distance L between adjacent chambers = 24 m, the limit boundary L of the single-hole model 1 = 15.93 m, and the safety factor is set as Fs = 1.5.

[0154] S10. Determine the equivalent slip surface inclination angle ω of the multi-hole model: Substitute the initiation angle and fracture angle obtained under the condition of the single-hole model into the buried depth control equation (29) of the multi-hole frustum model to get:

[0155]

[0156] L j = L / 2 - Rcosα = 24 / 2 - 6cos38.28 = 7.29,

[0157] L 0 = tanωL j = 7.29tanω,

[0158]

[0159] The equivalent slip surface inclination angle ω of the multi-hole model can be solved from the above formula as ω = 80.94°.

[0160] S11. Determine the calculated buried depth of the multi-hole model: Substitute the equivalent slip surface inclination angle ω of the multi-hole model calculated in the previous step into formula (30) to obtain the safe buried depth of the multi-hole correction model:

[0161] H = tanωL j-R + Rsinα = 7.29×tan80.97 - 6 + 6sin38.28 = 43.59。

[0162] S12. Output the final safe burial depth H = 43.59 m of the compressed air energy storage chamber under the condition of group tunnels.

[0163] This method can be used to determine the influence area of group tunnels, correct the calculated burial depth of a single tunnel, and evaluate the rationality of the plane layout scheme, which has important engineering significance for the burial depth design and stability evaluation of a tunnel-type gas storage reservoir; this method can solve the problems such as insufficient burial depth safety caused by ignoring the group tunnel effect in the existing burial depth calculation model, making the calculated burial depth result safer and more reasonable.

[0164] Embodiment 2

[0165] Based on Embodiment 1, this embodiment provides an electronic device, which includes a memory and at least one processor. The memory stores a computer program, and the processor is configured to execute the computer program to implement the above design method.

[0166] Specifically, the above-mentioned processor may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured as one or more integrated circuits for implementing the embodiments of the present application. Among them, the memory may include a mass storage for data or instructions. By way of example and not limitation, the memory may include a hard disk drive (HDD), a floppy disk drive, a solid state drive (SSD), a flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive, or a combination of two or more of these. In a suitable case, the memory may include a removable or non-removable (or fixed) medium. In a suitable case, the memory may be internal or external to the data processing device. In a specific embodiment, the memory is a non-volatile memory. In a specific embodiment, the memory includes a read-only memory (ROM) and a random access memory (RAM). In a suitable case, the ROM may be a mask-programmed ROM, a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), an electrically alterable ROM (EAROM), or a flash memory, or a combination of two or more of these.Where appropriate, the RAM may be a Static Random-Access Memory (SRAM) or a Dynamic Random Access Memory (DRAM). Among them, the DRAM may be a Fast Page Mode Dynamic Random Access Memory (FPMDRAM), an Extended Date Out Dynamic Random Access Memory (EDODRAM), a Synchronous Dynamic Random-Access Memory (SDRAM), etc.

[0167] The memory can be used to store or cache various data files required for processing and / or communication, as well as possible computer program instructions executed by the processor.

[0168] The processor reads and executes the computer program instructions stored in the memory to implement any of the methods in the above embodiments. In some of these embodiments, the electronic device may further include a communication interface and a bus. Among them, the processor, the memory, and the communication interface are connected through the bus and complete communication with each other.

[0169] A bus includes hardware, software, or both, and couples components of a computer device to each other. The bus includes at least one of the following, without limitation: a data bus, an address bus, a control bus, an expansion bus, a local bus. By way of example and not limitation, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Extended Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hyper Transport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an InfiniBand interconnect, a Low Pin Count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local Bus (VLB) bus, or other suitable bus or a combination of two or more of these. In suitable cases, the bus may include one or more buses. Although embodiments of the present application describe and illustrate specific buses, the present application contemplates any suitable bus or interconnect.

[0170] Embodiment 3

[0171] Based on Embodiment 1, this embodiment provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed, the above design method is implemented.

[0172] Those skilled in the art can understand that all or part of the steps of implementing the above method embodiments can be completed by hardware related to program instructions. The foregoing program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps including those of the above method embodiments. When the above integrated unit of the present invention is implemented in the form of a software functional unit and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the embodiments of the present invention, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the method described in Embodiment 1 of the present invention. The foregoing storage medium includes: various media that can store program codes, such as removable storage devices, ROMs, magnetic disks, or optical discs.

[0173] The foregoing is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for designing the buried depth of a gas storage cavern considering the influence of cavern groups, characterized in that: The following steps are involved: Based on the rigid cone model, under the condition of a group of caves, it is assumed that the fracture surface in the stress intersection area of ​​adjacent caverns is destroyed along the vertical shearing, forming a group of cave frustum model, wherein the fracture surface includes an oblique fracture surface and a vertical fracture surface; Compare the relationship between the center distance L between adjacent caverns and the limit boundary L1 of the single cave model to determine whether the distance between adjacent caverns exceeds the influence area of ​​the cave group. If so, perform force analysis based on the rigid cone model and calculate the burial depth; If not, based on the group hole cone model, by considering the cohesion and internal friction angle on the fracture surface, a force balance equation between the resistance and the lifting force is established to obtain the buried depth control equation of the group hole cone model, thereby calculating the buried depth; The single-hole model limit boundary L1 is the horizontal distance between the center of the cavern and the ground rupture boundary under the rigid cone model condition.

2. The method for designing the buried depth of a gas storage cavern according to claim 1 is characterized in that: When judging whether the distance between adjacent caverns exceeds the influence area of ​​cavern clusters, it is judged whether L / 2-L1≥0 is satisfied. If so, it indicates that the distance between adjacent caverns has exceeded the influence area of ​​cavern clusters. If not, it indicates that the distance between adjacent caverns is small and is still in the influence area of ​​cavern clusters.

3. The method for designing the buried depth of a gas storage cavern according to claim 1 is characterized in that: In the case of calculating the burial depth based on the rigid cone model, the limit equilibrium method is used to establish the burial depth control equation f1, and the rupture angle β, burial depth H, safety factor F s As the adjustment control quantity, the expression of the burial depth control equation under the single hole condition is obtained as follows: f1(β,H,F s )=E a边侧 (β,H,F s )-E a单中间 (H)=0, Among them, E a边侧 It represents the vertical main force under the condition of force balance of the side triangle, E a边侧 (β, H, F s ) means E a边侧 and rupture angle β, burial depth H, safety factor F s All related, E a单中间 It represents the vertical main force under the condition of force balance of the middle block under the condition of single hole, E a单中间 (H) stands for E a单中间 Related to the burial depth H; The steps to calculate the burial depth include: S1: In E a单中间 When (H) = 0, the initial cycle setting burial depth H0 is obtained; S2: Safety factor F s The initial setting is 1, and the initial cycle setting depth H0 is substituted into E a边侧 (β, H, F s ) to solve E a边侧 The minimum value of E a边侧 The rupture angle corresponding to the minimum value of is set as the initial cycle rupture angle β0; S3: In F s = 1, the initial cycle rupture angle β0 is substituted into the burial depth control equation f1(β, H, F s )=0, solve again to get the burial depth H1; S4: Compare the difference between H0 and H1 to see if it meets the accuracy requirement; if not, replace H1 with E in step S2. a边侧 (β, H, F s ) Solve for E a边侧 The minimum value of E a边侧 The rupture angle corresponding to the minimum value of is reset as the initial cycle rupture angle β0, and the initial cycle rupture angle β0 and the burial depth H1 are solved cyclically until the difference between H0 and H1 meets the accuracy requirement; When the difference between H0 and H1 meets the accuracy requirement, determine the burial depth H1 and the initial cycle rupture angle β0; S5: Substitute the initial cycle rupture angle β0 corresponding to the burial depth H1 that meets the accuracy requirements into the burial depth control equation f1 (β, H, F s )=0, and reset the safety factor F according to the design requirements s , solve the final safe burial depth H.

4. The method for designing the buried depth of a gas storage cavern according to claim 1, characterized in that: The steps to obtain the depth control equation of the cave group cone model include: According to the position of the crack initiation point and the position of the adjacent cavern center axis, the cave group cone model is divided into a middle block and a side trapezoidal block; the force balance equation is established with the middle block and the side trapezoidal block as the research object, and the main force E on the vertical plane is obtained when the middle block is the research object. a群中间 and the active force E on the vertical plane when the side trapezoidal block is taken as the research object a边侧梯形 , thus obtaining the control equation of the buried depth of the cave cone model: f2 = E a边侧梯形 -E a群中间 =0; The crack initiation point is the intersection of the fracture surface on the cross-sectional contour of the cave.

5. The method for designing the buried depth of a gas storage cavern according to claim 4 is characterized in that: The E a边侧梯形 It is derived from the case where the side trapezoidal block is simplified to a side triangle. The simplification method is: the line from the intersection of the vertical fracture surface and the ground to the crack initiation point is used as the equivalent slip surface, the equivalent slip surface is used to be equivalent to the fracture surface, and the force of the side trapezoidal block is simplified to the force of the side triangular block according to the vector polygon criterion, so as to establish the force balance equation based on the side triangular block to obtain the E a边侧梯形 .

6. The method for designing the buried depth of a gas storage cavern according to claim 5 is characterized in that: When calculating the burial depth based on the burial depth control equation of the group-hole frustum model, the rupture angle β is first obtained according to the burial depth control equation under the single-hole condition, and then the rupture angle β is substituted into the burial depth control equation of the group-hole frustum model to calculate the equivalent slip surface inclination angle ω; finally, the burial depth H is calculated according to the equivalent slip surface inclination angle ω.

7. The method for designing the buried depth of a gas storage cavern according to claim 6 is characterized in that: The buried depth control equation f2 of the cave group cone model is expressed as: Where G1 is the weight of the side trapezoidal block, C is the contact surface cohesion between the side trapezoidal block and the middle block, is the friction angle of the rock mass after reduction, ω is the inclination angle of the equivalent slip surface, C s is the cohesion on the equivalent slip surface, φ is the main force E on the non-fracture surface a The angle with the horizontal plane, P is the uplift force of the cavern, G0 is the weight of the middle block, and R is the radius of the cavern.

8. The method for designing the buried depth of a gas storage cavern according to claim 6 is characterized in that: The burial depth is calculated by the following expression: H = tanωL j -R+Rsinα; where ω is the equivalent slip surface inclination angle, L j is the horizontal distance from the crack initiation point to the ground rupture boundary, R is the hole diameter, and α is the crack initiation angle.

9. An electronic device, characterized in that: The electronic device comprises a memory and at least one processor, the memory stores a computer program, and the processor is used to execute the computer program to implement the burial depth design method according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed, the burial depth design method according to any one of claims 1 to 8 is implemented.

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