Underground water-sealed cave depot vertical shaft sealing plug and parameter determination method thereof

Abstract

The invention provides an underground water-sealed cave depot vertical shaft sealing plug and a parameter determination method thereof.The sealing plug comprises an integrally-formed main column body and at least two annular protrusions, and the protrusions are externally connected to the outer circumference of the main column body and extend outwards in the radial direction of the main column body; the section of the bulge in the length direction of the main column body is triangular; the sealing plug adopts the mode that the main column body is combined with the annular protrusions, the combination face of the sealing plug and the vertical shaft is increased, the bearing capacity of the sealing plug is remarkably improved, meanwhile, during construction in the vertical shaft, only secondary excavation needs to be conducted on the protrusions, the work amount is small, construction is convenient, the forming effect of the sealing plug is good, and the amount of added concrete is small. By adopting the parameter determination method provided by the invention, the parameters of the sealing plug can be determined for a specific vertical shaft so as to provide proper bearing capacity.

Description

Technical Field

[0001] The invention belongs to the field of underground water-sealed caverns, and in particular relates to a vertical shaft sealing plug for an underground water-sealed cavern and a method for determining its parameters. Background Art

[0002] An underground water-sealed petroleum cavern is a large-scale cavern complex artificially excavated into rock at a depth below the stable groundwater level. It is used to store petroleum resources such as crude oil, liquefied petroleum gas, and refined products. It primarily consists of a main cavern complex, connecting tunnels, construction tunnels, ventilation shafts, and process shafts.

[0003] The process shaft connects the surface to the underground oil storage caverns and serves as a passage for oil products to enter and exit. After construction is complete, the shaft must be sealed with a sealing plug to isolate the oil products from the external environment, creating an independent, enclosed storage space. The sealing plug is typically located at the bottom of the shaft, near the top arch of the oil storage cavern. Suspended in the shaft, the sealing plug must support the load of approximately 100 meters of process piping, backfill bentonite, and backfill water above it. Due to its long burial depth and heavy overhead loads, the sealing plug can withstand loads of 3,000-5,000 tons. Therefore, a stable sealing plug structure is crucial for the safe operation of the project. The process shaft and sealing plug are generally designed to be located in areas with good geological conditions and surrounding rock properties. However, due to the overall project layout, the shaft sealing plug section inevitably develops unfavorable structures such as alteration and fracture zones, making conventional sealing plugs unable to meet the load-bearing requirements. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide an underground water-sealed cavern shaft sealing plug and a parameter determination method thereof, so that it has the advantage of greater bearing capacity and can adapt to various geological conditions, especially soft surrounding rock conditions.

[0005] The present invention discloses an underground water-sealed cavern shaft sealing plug, comprising an integrally formed main column and at least two annular protrusions, wherein the protrusions are circumscribed to the outer circumference of the main column and extend radially outwardly along the main column; the cross-section of the protrusions along the length direction of the main column is triangular; The sealing plug satisfies the following formula: ; Where: γ0 is the structural importance coefficient; is the design condition coefficient; G1 is the deadweight of the sealing plug; G2 is the deadweight of the backfill bentonite; G3 is the deadweight of the filling water; F is the process pipeline load; θ i is the angle between the lower side wall of the i-th protrusion from top to bottom and the vertical, i is 1, 2, ... n, n ≥ 2; θ n is the angle between the lower side wall of the nth protrusion and the vertical; γ d is the basic combination structure coefficient; fR is the shear friction coefficient of the concrete and bedrock contact surface; G i is the weight of the partial sealing plug from the top of the i-th protrusion to the bottom of the wall, C R is the shear cohesion of the concrete and bedrock contact surface; λ is the effective area coefficient of the contact surface; A is the lateral surface area of the sealing plug in contact with the shaft bedrock surface; From top to bottom, the upper edge of the first protrusion is flush with the upper edge of the column, and the lower edge of the last protrusion is flush with the lower edge of the column.

[0006] The sealing plug adopts the form of a main column combined with a plurality of annular protrusions, which increases the combined surface of the sealing plug and the shaft, significantly improves the carrying capacity of the sealing plug, and at the same time, only needs to excavate the protrusions again during construction in the shaft, the engineering quantity is small, the construction is convenient, the forming effect of the sealing plug is good, and the increased concrete quantity is small.

[0007] Further, the ring width of the protrusion is 1.0m-2.0m to ensure the carrying strength of the protrusion.

[0008] Further, from top to bottom, the ring width of the protrusion increases in turn to further improve the carrying capacity of the sealing plug.

[0009] Further, from top to bottom, the height of the protrusion increases in turn to further improve the carrying capacity of the sealing plug.

[0010] Further, it further comprises a first column, and the lower end of the first column is connected to the upper end of the main column as a whole. Increasing the first column at the upper end of the main column of the sealing plug can improve the anchoring force of the process pipeline and the concrete structure of the sealing plug, and reduce the stress concentration phenomenon at the junction of the first protrusion at the uppermost edge and the main column.

[0011] Further, the height of the first column is 0.5m-1.0m to ensure smooth stress transition.

[0012] Further, it further comprises a second column, and the upper end of the second column is connected to the lower end of the main column as a whole. Similarly, increasing the second column at the lower end of the main column of the sealing plug can improve the anchoring force of the process pipeline and the concrete structure of the sealing plug, and reduce the stress concentration phenomenon at the junction of the last protrusion at the lowermost edge and the main column.

[0013] Further, the height of the second column is 0.5m-1.0m to ensure smooth stress transition.

[0014] Another aspect of the present application also provides a method for determining the parameters of a sealing plug for a shaft of a groundwater-sealed cavern, which is used to determine the size parameters of the sealing plug for the shaft of the groundwater-sealed cavern, and comprises the following steps: S1, calculate the self-weight of backfill bentonite G2, the self-weight of filling water G3 and the load of process pipeline F; S2, determine the position of the sealing plug in the shaft and the shear friction coefficient f of the concrete and bedrock contact surface R And the shear cohesion C of the concrete and bedrock contact surface R ; S3, determine the size parameters H, d0, di, h i-1 , h i-2 , θ i , Hi of the sealing plug body; H is the total height of the sealing plug, d0 is the diameter of the main column, di is the ring width of the i-th protrusion from top to bottom, h i-1 is the height of the upper side wall of the i-th protrusion, h i-2 is the height of the lower side wall of the i-th protrusion, θ i is the vertical angle of the lower side wall of the i-th protrusion from top to bottom, i is 1, 2, … n, n≥2; Hi is the height of the part of the sealing plug to the lower side wall of the i-th protrusion; and calculate the self-weight G1 of the sealing plug; S4, calculate the action effect function S(.) and the anti-sliding stability resistance function R(.), of the sealing plug, , ; θ n is the vertical angle of the lower side wall of the n-th protrusion; G i is the self-weight of the part of the sealing plug to the lower side wall of the i-th protrusion; θ i is the vertical angle of the lower side wall of the i-th protrusion from top to bottom, i is 1, 2, … n, n≥2; λ is the effective area coefficient of the contact surface; A is the side surface area of the sealing plug in contact with the bedrock surface of the shaft; S5, if , γ0 is the structure importance coefficient; is the design condition coefficient; γ d is the basic combination structure coefficient; That is: , the design is completed, otherwise go to S3.

[0015] Further, the S3 further comprises determining the height h1 of the first column, and / or determining the height h2 of the second column.

[0016] The present application has the following beneficial effects: 1) The sealing plug designed in the present application comprises a plurality of annular protrusions, thereby having multiple bedrock contact surfaces, which can provide higher bearing capacity, and can be applied to sealing the underground oil storage cavern in the process shaft when the overall layout is limited by the adverse geological bodies such as alteration zone and fracture zone, thereby avoiding the problems of high engineering cost, great difficulty and long demonstration period caused by adjusting the position of the process shaft; 2) The sealing plug designed in the application has the advantages of small secondary excavation amount, small increase in concrete amount, convenient construction, and small increase in construction period, and is beneficial to engineering investment control and construction period guarantee. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a sectional view of the sealing plug of the underground water-sealed cavern vertical shaft provided by some embodiments of the application, Figure 2 is a sectional view of the sealing plug of the underground water-sealed cavern vertical shaft provided by some embodiments of the application, Figure 3 is a sectional view of the sealing plug of the underground water-sealed cavern vertical shaft provided by some embodiments of the application, Figure 4 is a radial sectional view of the sealing plug of the underground water-sealed cavern vertical shaft provided by some embodiments of the application, a is a cross section of the main column, b is a cross section of the wide part of the first protrusion, and c is a cross section of the wide part of the second protrusion, Figure 5 is a flow chart of the parameter determination method of the sealing plug of the underground water-sealed cavern vertical shaft provided by some embodiments of the application, Figure 6 is a sectional view of the sealing plug of the underground water-sealed cavern vertical shaft provided by some embodiments of the application, and the length unit in the figure is mm; Explanation of reference signs: 00 main column, 01 first protrusion, 02 second protrusion, 11 first column, and 22 second column; d0 diameter of the main column, d1 ring width of the first protrusion, D1 outer diameter of the first protrusion, d2 ring width of the second protrusion, D2 outer diameter of the second protrusion, h1 height of the first column, h1-1 height of the upper side wall of the first protrusion, h1-2 height of the lower side wall of the first protrusion, h2-1 height of the upper side wall of the second protrusion, h2-2 height of the lower side wall of the second protrusion, h1 height of the second column, H1 height of the part of the sealing plug from the top to the lower side wall of the first protrusion, H2 height of the part of the sealing plug from the top to the lower side wall of the second protrusion, and H total height of the sealing plug. DETAILED DESCRIPTION

[0018] In order to more clearly and completely describe the technical solutions of the application, the application is further described in detail through specific embodiments below. It should be understood that the specific embodiments described herein are only used to explain the application and do not limit the application, and various changes can be made within the scope of the application.

[0019] It should be noted that the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance. The terms "vertical", "horizontal", "left", "right" and similar expressions are only for illustrative purposes and do not represent the only embodiment. The term "and / or" includes any and all combinations of one or more related listed items. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as understood by those skilled in the art to which the present application belongs. The terms used in the specification of the present application herein are only for the purpose of describing the specific embodiments and are not intended to limit the present application.

[0020] As shown in Figure 1 , in one embodiment provided by the present application, the underground water-sealed cave vertical shaft sealing plug comprises a main column 00 and no less than two annular protrusions, the protrusions circumscribe the outer circumference of the main column 00 and extend radially outward along the main column 00; the cross section of the protrusions along the length direction of the main column is triangular; the ring width of the protrusions is 1.0m-2.0m; from top to bottom, the upper edge of the first protrusion is flush with the upper edge of the column, and the lower edge of the last protrusion is flush with the lower edge of the column; the multiple protrusions are named from top to bottom as protrusion one, protrusion two and the last protrusion; for example, there are n protrusions, n is 4, the first protrusion from top to bottom is protrusion one, the second protrusion is protrusion two, the third protrusion is protrusion three, and the n-th protrusion, i.e. the fourth protrusion, is protrusion four. Optionally, from top to bottom, the ring width of the protrusions increases successively; from top to bottom, the height of the protrusions increases successively.

[0021] As shown in Figure 4 , the outer diameters of the main column, the protrusion one and the protrusion two increase successively.

[0022] As shown in Figure 2 , in another embodiment provided by the present application, the underground water-sealed cave vertical shaft sealing plug further comprises a first column 11, the lower end of the first column 11 and the upper end of the main column 00 are connected as one body. The height of the first column 11 is 0.5m-1.0m.

[0023] As shown in Figure 3 , in another embodiment provided by the present application, in addition to the first column 11, the underground water-sealed cave vertical shaft sealing plug further comprises a second column 22, the upper end of the second column 22 and the lower end of the main column 00 are connected as one body. The height of the second column 22 is 0.5m-1.0m.

[0024] As shown in Figure 5 , the method for determining the shape size parameters of the above underground water-sealed cave vertical shaft sealing plug provided by the present application comprises the following steps: S1, calculating the self-weight of backfill bentonite G2, the self-weight of filling water G3 and the load of process pipeline F; S2. Determine the position of the sealing plug in the shaft and the shear friction coefficient f of the contact surface between concrete and bedrock R ' and the shear cohesion C of the contact surface between concrete and bedrock R '; S3. Determine the size parameters of the sealing plug H, d0, di, h i-1 、h i-2 ,θ i , Hi; H is the total height of the sealing plug, d0 is the diameter of the main column 00, di is the ring width of the i-th protrusion from top to bottom, h i-1 is the height of the upper side wall of the i-th protrusion, h i-2 is the height of the lower side wall of the i-th protrusion, θ i is the angle between the lower side wall of the i-th protrusion and the vertical, where i is 1, 2, ..., n, and n ≥ 2; Hi is the height of the sealing plug up to the lower side wall of the i-th protrusion; and the deadweight G1 of the sealing plug is calculated; S4. Calculate the sealing plug's effect function S(.) and anti-sliding stability resistance function R(.), , θ n G is the angle between the lower side wall of the nth protrusion and the vertical; i is the weight of the sealing plug up to the lower side wall of the i-th protrusion; θ i is the angle between the lower side wall of the i-th protrusion from top to bottom and the vertical, i is 1, 2, ... n, n ≥ 2; λ is the effective area coefficient of the contact surface; A is the side surface area of ​​the sealing plug in contact with the bedrock surface of the shaft; S5. If satisfied , γ0 is the structural importance coefficient; is the design condition coefficient; γ d is the basic combination structure coefficient; Right now: , then the design is completed, otherwise go to S3.

[0025] In one embodiment, S3 further includes determining the height h1 of the first column 11 ; in another embodiment, S3 further includes determining the height h1 of the first column 11 and determining the height h2 of the second column 11 .

[0026] Example

[0027] With a groundwater sealed cavern project in a certain place in China as an example, the project is arranged with eight process shafts, the process shafts have a depth of about 140.0 m, are divided into oil inlet shafts and oil outlet shafts, the oil inlet shafts have a net diameter of 5.0 m and are arranged with oil inlet pipelines, the oil outlet shafts have a net diameter of 6.0 m and are arranged with oil outlet pipelines and other process pipelines, instruments, cables and their casings and the like. In order to ensure the safety and water sealing of the oil storage space, one sealing plug is arranged at a depth of about 125.0 m at the bottom of each process shaft. In the excavation process, the sealing plug sections of five process shafts are exposed with different degrees of alteration zone, for example, the oil inlet shaft has a diameter of 5.3 m, the original design adopts a single key groove sealing plug of grade III surrounding rock, and the bearing capacity cannot meet the requirements.

[0028] The sealing plug provided by the present application is used, the sealing plug has a size as shown in Figure 6 , the shear fracture friction coefficient f R of the concrete and the bedrock contact surface is 0.7, the shear fracture cohesion C R of the concrete and the bedrock contact surface is 0.3 MPa, the self weight G1 of the concrete sealing plug is 6195 kN, the self weight G2 of the backfill bentonite is 3240 kN, the self weight G3 of the filling water is 21206 kN, the process pipeline load F is 1000 kN, the effective area coefficient λ of the contact surface is 0.5 for the straight wall section, 0 for the upper side wall of the protrusion and 1.0 for the lower side wall of the protrusion, the structure safety grade is divided into grade I, grade II and grade III, and the structure importance coefficient γ0 is respectively taken as 1.1, 1.05 and 1.0, and in the embodiment, 1.1 is taken. According to the permanent design condition, the transient design condition and the accidental design condition, the design condition coefficient is respectively taken as 1.0, 0.95 and 0.85, and in the embodiment, 1.0 is taken. The sealing plug structure is calculated by using the anti-sliding stability limit state design, and the basic combination structure coefficient γ d of the specification is taken as 1.5. Through calculation, the anti-sliding stability resistance function of the sealing plug provided by the present application is 36807 kN, which is increased by 76.5% compared with the anti-sliding stability resistance function 20850 kN of the original design of the single key groove sealing plug of grade III surrounding rock.

[0029] At the same time, the calculation results are as follows: , , which satisfy the formula: .

[0030] In the formula, γ0 is the structure importance coefficient; is the design condition coefficient; G1 is the self weight of the sealing plug; G2 is the self weight of the backfill bentonite; G3 is the self weight of the filling water; F is the process pipeline load; θ iis the angle between the ith protrusion lower side wall and the vertical direction, i is 1, 2, …n, n≥2; θ n is the angle between the nth protrusion lower side wall and the vertical direction; γ d is the basic combination structure coefficient; f R is the shear friction coefficient of the concrete and bedrock contact surface; G i is the self weight of the partial sealing plug to the ith protrusion lower side wall, C R is the shear cohesion of the concrete and bedrock contact surface; λ is the effective area coefficient of the contact surface; A is the side surface area of the sealing plug in contact with the shaft bedrock surface.

[0031] The sealing plug designed in the present application can be applied to process shafts in poor geological conditions such as alteration zones and fracture zones, and provides sealing function for underground water-sealed cavern projects.

[0032] The technical features of the above-described embodiments can be combined in any manner, and for the sake of brevity, not all possible combinations of the technical features in the above-described embodiments are described, however, as long as the combination of the technical features does not exist contradictions, it should be considered as the scope of the present application.

Claims

1. A sealing plug for an underground water-sealed cavern shaft, characterized in that: It comprises an integrally formed main column (00) and no less than two annular protrusions, wherein the protrusions are circumscribed to the outer circumference of the main column (00) and extend radially outward along the main column (00); the cross section of the protrusions along the length direction of the main column is triangular; The sealing plug satisfies the following formula: ； Where: γ0 is the structural importance coefficient; is the design condition coefficient; G1 is the deadweight of the sealing plug; G2 is the deadweight of the backfill bentonite; G3 is the deadweight of the filling water; F is the process pipeline load; θ i is the angle between the lower side wall of the i-th protrusion from top to bottom and the vertical, i is 1, 2, ... n, n ≥ 2; θ n is the angle between the lower side wall of the nth protrusion and the vertical; γ d is the basic combination structure coefficient; f R ' is the shear friction coefficient of the contact surface between concrete and bedrock; G i is the weight of the sealing plug up to the lower side wall of the ith protrusion, C R '—the shearing cohesion of the contact surface between concrete and bedrock; λ is the effective area coefficient of the contact surface; A is the side surface area of ​​the sealing plug in contact with the bedrock surface of the shaft; From top to bottom, the upper edge of the first protrusion is flush with the upper edge of the column, and the lower edge of the last protrusion is flush with the lower edge of the column.

2. The underground water seal cave shaft sealing plug according to claim 1, characterized in that: The ring width of the protrusion is 1.0m-2.0m.

3. The underground water seal cave shaft sealing plug according to claim 1, characterized in that: From top to bottom, the ring width of the protrusion increases successively.

4. The underground water seal cave shaft sealing plug according to claim 1, characterized in that: From top to bottom, the heights of the protrusions increase successively.

5. The underground water seal cave shaft sealing plug according to claim 1, characterized in that: It also includes a first column (11), the lower end of the first column (11) and the upper end of the main column (00) are connected as a whole.

6. The underground water-sealed cavern shaft sealing plug according to claim 5, characterized in that: The height of the first column (11) is 0.5m-1.0m.

7. The underground water-sealed cavern shaft sealing plug according to claim 1, characterized in that: It also includes a second column (22), the upper end of the second column (22) and the lower end of the main column (00) being connected as one body.

8. The underground water-sealed cavern shaft sealing plug according to claim 7, characterized in that: The height of the second column (22) is 0.5m-1.0m.

9. A method for determining parameters of a vertical shaft sealing plug for an underground water-sealed cavern, characterized in that: The method for determining the shape and size parameters of the underground water-sealed cavern shaft sealing plug according to any one of claims 1 to 8 comprises the following steps: S1. Calculate the backfill bentonite deadweight G2, backfill water deadweight G3 and process pipeline load F; S2. Determine the position of the sealing plug in the shaft and the shear friction coefficient f of the contact surface between concrete and bedrock R ' and the shear cohesion C of the contact surface between concrete and bedrock R '; S3. Determine the size parameters of the sealing plug H, d0, di, h i-1 、h i-2 ,θ i 、Hi;H is the total height of the sealing plug, d0 is the diameter of the main column (00), di is the ring width of the i-th protrusion from top to bottom, h i-1 is the height of the upper side wall of the i-th protrusion, h i-2 is the height of the lower side wall of the i-th protrusion, θ i is the angle between the lower side wall of the i-th protrusion and the vertical, where i is 1, 2, ..., n, and n ≥ 2; Hi is the height of the sealing plug up to the lower side wall of the i-th protrusion; and the deadweight G1 of the sealing plug is calculated; S4. Calculate the sealing plug's effect function S(.) and anti-sliding stability resistance function R(.), , θ n G is the angle between the lower side wall of the nth protrusion and the vertical; i is the weight of the sealing plug up to the lower side wall of the i-th protrusion; θ i is the angle between the lower side wall of the i-th protrusion from top to bottom and the vertical, i is 1, 2, ... n, n ≥ 2; λ is the effective area coefficient of the contact surface; A is the side surface area of ​​the sealing plug in contact with the bedrock surface of the shaft; S5. If satisfied , γ0 is the structural importance coefficient; is the design condition coefficient; γ d is the basic combination structure coefficient; Right now: , then the design is completed, otherwise go to S3.

10. The method for determining parameters of underground water-sealed cavern shaft sealing plugs according to claim 9, characterized in that: Said S3 further comprises determining the height h1 of the first column (11), and / or determining the height h2 of the second column (22).

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