Construction method of ring beam concrete foundation of large oil storage tank

Abstract

This invention provides a construction method for a concrete foundation ring beam for a large oil storage tank, belonging to the technical field of tank ring beam construction. The method includes the following steps: A. Construction preparation; B. Tank foundation excavation and backfilling; C. Ring beam construction; D. Backfilling within the ring beam: First, lay a layer of HDPE membrane on the road base layer inside the ring beam. Then, layer by layer, lay a second asphalt sand cushion layer → geotextile layer → graded crushed stone cushion layer → HDPE membrane → medium-coarse sand cushion layer → multi-layered bonded foam board layer → waterproof asphalt layer → graded crushed stone cushion layer → waterstop layer → cement fiberboard layer → third asphalt sand cushion layer → polytetrafluoroethylene layer; E. Backfilling outside the ring beam: Lay a layer of HDPE membrane on the road base layer inside and outside the ring beam. Then, layer by layer, lay a second asphalt sand cushion layer → medium-coarse sand cushion layer → concrete pavement layer outside the ring beam; F. Complete the overall construction of the ring beam and hand it over. This invention can effectively solve the problem of oil leakage into the soil from the foundation of large storage tanks.

Description

Technical Field

[0001] This invention relates to the field of tank ring beam construction technology, and more specifically, to a method for constructing a concrete foundation for a large oil storage tank ring beam. Background Technology

[0002] Petroleum, one of the main targets of geological exploration, is a viscous, dark brown liquid known as the "blood of industry." Petroleum is stored in some areas of the upper crust. Its main components are a mixture of various alkanes, cycloalkanes, and aromatic hydrocarbons. Large oil storage tanks are essential for the storage of petroleum products. These tanks play a strategic role in national economic development, transportation, and military fields.

[0003] However, due to factors such as the engineering environment and working conditions of oil tanks, oil leakage often occurs at the bottom plate of the tank. The leaked oil-water mixture is highly corrosive, and once it seeps into the soil of the tank area, it will cause serious environmental pollution, leading to serious engineering accidents and economic losses. Therefore, under the requirements of safety and environmental protection, it is of great significance to do a good job in the anti-seepage design of the tank area. Effectively solving the leakage problem of oil-water mixture in the tank area can effectively avoid pollution accidents and economic losses. Summary of the Invention

[0004] The purpose of this invention is to provide a construction method for a large oil storage tank ring beam concrete foundation, which can effectively solve the problem of oil leakage into the soil from the foundation of large storage tanks.

[0005] The embodiments of the present invention are achieved through the following technical solution: a construction method for a concrete foundation ring beam of a large oil storage tank, comprising the following steps:

[0006] A. Construction preparation: Survey and clean the construction site, level the site, use instruments such as total station and precision level to conduct construction surveying and positioning according to the drawings and data, and use paint to draw lines in the fixed points and positioning areas, and draw the projection area of ​​the ring beam on the road base layer as specified in the construction drawings.

[0007] B. Excavation and backfilling of tank foundation: First, excavate an annular groove on the road base and directly below the ring beam. The cross-section of the annular groove is trapezoidal. Lay a layer of HDPE film on the side wall of the annular groove. Then, fill a layer of coarse sand cushion into the annular groove. Lay a first asphalt sand cushion on top of the coarse sand cushion. At the same time, pour a plain concrete cushion in the first asphalt sand cushion. The top wall of the annular plain concrete cushion is flush with the road base.

[0008] C. Ring beam construction: The ring beam is poured by pouring concrete layer by layer on top of the plain concrete pad. The pouring height of each ring beam is 30-50mm. Reinforcing bars are tied, formwork is erected and reinforced layer by layer. Each ring beam layer must be poured and formed as a whole. Concrete is poured and vibrated to compact it layer by layer until the required construction height in the drawings is reached.

[0009] D. Backfilling construction inside the ring beam: First, lay a layer of HDPE membrane on the road base inside the ring beam, and then lay the second asphalt sand cushion layer → geotextile layer → graded crushed stone cushion layer → HDPE membrane → medium and coarse sand cushion layer → multi-layered foam board layer → waterproof asphalt layer → graded crushed stone cushion layer → waterstop layer → cement fiber board layer → third asphalt sand cushion layer → polytetrafluoroethylene layer in sequence.

[0010] E. Backfilling construction outside the ring beam: Lay a layer of HDPE film on the inner and outer road base of the ring beam, and lay the second asphalt sand cushion layer → medium and coarse sand cushion layer → concrete pavement layer layer by layer outside the ring beam.

[0011] F. Complete the overall construction of the ring beam and hand it over.

[0012] Furthermore, the ring beam construction described in step C also includes: pouring concrete for each layer from the same point in opposite directions until the concrete layer is completed.

[0013] Furthermore, the backfilling construction inside the ring beam described in step D also includes: the waterstop layer, cement fiberboard layer, third asphalt sand cushion layer, and polytetrafluoroethylene layer inside the ring beam are all inclined downwards at 9-12 degrees from the center of the ring beam to the surrounding area.

[0014] Furthermore, an impermeable membrane is laid between the concrete pavement layer outside the ring beam and the second asphalt sand cushion layer, and within the medium-coarse sand cushion layer. The impermeable membrane is attached to the ring beam and has an 'L' shaped cross section.

[0015] Furthermore, the ring beam is circumferentially connected with multiple leak detection tubes. One end of each leak detection tube extends into the graded crushed stone cushion layer above the waterproof asphalt layer inside the ring beam, and the other end extends out of the ring beam. The leak detection tubes are also inclined.

[0016] The technical solutions of the embodiments of the present invention have at least the following advantages and beneficial effects:

[0017] 1. This invention, by laying an HDPE membrane above the annular groove and the road base layer, can prevent oil from seeping into the road base layer. The first asphalt sand cushion layer inside the annular groove not only blocks leakage but also ensures the strength of the ring beam. The HDPE membrane, second asphalt sand cushion layer, geotextile layer, graded crushed stone cushion layer, HDPE membrane, medium-coarse sand cushion layer, multi-layered bonded foam board layer, waterproof asphalt layer, graded crushed stone cushion layer, waterstop layer, cement fiberboard layer, third asphalt sand cushion layer, and polytetrafluoroethylene layer within the ring beam all effectively prevent oil seepage. To prevent oil leakage, this paving method has undergone numerous tests and has demonstrated excellent barrier effects and low construction costs. Meanwhile, the medium-coarse sand cushion layer, graded crushed stone cushion layer, and cement fiberboard layer provide good support, ensuring the stability of the oil storage tank. Furthermore, the second asphalt sand cushion layer, concrete pavement layer, and impermeable membrane outside the ring beam further prevent oil leakage. Moreover, the layer-by-layer construction of the ring beam ensures its strength and effectively prevents cracks. Thus, it effectively prevents oil from leaking into the soil, avoiding environmental pollution and economic losses.

[0018] 2. This invention, by setting the cement fiberboard layer, waterstop layer, third asphalt sand pad layer, and polytetrafluoroethylene layer inside the ring beam at a 9-12 degree downward angle from the center of the ring beam, can guide oil into the annular groove when oil leakage occurs, facilitating subsequent cleaning and saving costs. Furthermore, by checking whether the leak detection pipe is leaking oil, it is very convenient to check whether the oil storage tank is leaking. The operation is very simple and convenient. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A partial sectional view of the construction structure of the large oil storage tank ring beam concrete foundation provided by the present invention.

[0021] Figure 2 A schematic diagram of the casting direction of the ring beam provided by the present invention;

[0022] Figure 3 A schematic diagram of the structure of the oil storage tank after it is installed on the ring beam, as provided by the present invention;

[0023] Figure 4 This is a schematic diagram of the ring beam and reinforcing bars provided by the present invention.

[0024] Icons: 1-Road base course, 11-Annular groove, 111-HDPE membrane, 112-Coarse sand cushion layer, 113-First asphalt sand cushion layer, 2-Plain concrete cushion layer, 3-Ring beam, 31-Reinforcing steel, 32-Second asphalt sand cushion layer, 33-Geotextile layer, 34-Graded crushed stone cushion layer, 35-Medium-coarse sand cushion layer, 36-Foam board layer, 37-Waterproof asphalt layer, 38-Waterstop layer, 39-Cement fiberboard layer, 40-Third asphalt sand cushion layer, 41-PTFE layer, 5-Concrete pavement layer, 51-Imperile membrane, 6-Leak detection pipe, 71-Pouring direction, 8-Site floor, 9-Oil storage tank, 91-Sump, 92-Highest oil level. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0027] Example

[0028] The following description, in conjunction with specific embodiments, provides further details. Figures 1-4 As shown, this invention provides a method for constructing a concrete foundation for a ring beam of a large oil storage tank, comprising the following steps:

[0029] Firstly, in this implementation, the oil storage tank D=96000mm, the water collection pit D=660mm, the inner diameter of the ring beam 3 D=95500mm, the geotextile is 300g / m2 non-woven, the HDPE membrane 111 is 2mm thick, and the plain concrete is C20. The inner bottom wall of the oil storage tank 9 is equipped with a water collection pit 91, which allows oil residue to be collected in the water collection pit 91.

[0030] A. Construction Preparation: Survey and clear the construction site, use excavators, bulldozers and other machinery to level the site, and use total stations, precision levels and other instruments to conduct construction surveying and positioning according to the drawings. Use paint to draw lines in the designated areas, marking the projection area of ​​the ring beam 3 on the road base 1 as specified in the construction drawings. In construction surveying, coordinate measurement control is the preferred method, using a total station to transfer coordinate control points provided by the client. The measuring instruments must undergo rigorous testing and calibration. Measurements should be conducted as early as possible in the morning, evening, on cloudy days, or under windless conditions to minimize the influence of side refraction. A cross-shaped coordinate control network should be established. A central control stake is set at the center of the tank, and four coordinate positioning stakes are set on the longitudinal and transverse center lines of the tank foundation to facilitate layout and verification during construction. The coordinate positioning stakes are set on a solid foundation at a distance of more than 15m from the edge of the foundation trench, in a location unaffected by vibration, pedestrian or vehicle traffic, or construction. The axis is then extended to the roads and walls around the tank area, and markers are set on the roads and walls to facilitate the verification of the positioning stakes. The control stakes are made of 1.5m long wooden stakes driven into the soil, with about 10cm exposed. Small nails are nailed on the stakes as control points for the axis. Loose soil is removed, and concrete is poured for protection to prevent deviation. Human damage is strictly prohibited. If any loosening is found, the stakes must be re-measured.

[0031] During the construction of the tank foundation ring beam 3, the edge line of the foundation trench excavation is determined by measuring with a steel ruler based on the control stake at the center of the tank. After backfilling with crushed stone, the ring beam 3 cushion layer is constructed, and the control stake at the center of the tank is re-measured using the control stakes around the perimeter. After the ring beam 3 cushion layer is constructed, the edge line of the ring beam 3 is determined by measuring with a steel ruler and plumb line based on the control stake at the center of the tank. A point is marked on the cushion layer every 2m. Using an arc-shaped plate that has been laid out on the flat ground according to the curvature of the ring beam 3, the inner and outer edge lines of the tank foundation ring beam 3 are drawn according to the principle of "two points determine one line" to facilitate the support of the inner and outer formwork of the ring beam 3.

[0032] B. Excavation and backfilling of tank foundation: First, excavate an annular groove 11 on the road base 1 and directly below the ring beam 3. The cross-section of the annular groove 11 is an equilateral trapezoid. The length of the top wall of the annular groove 11 is greater than the length of the bottom wall of the annular groove 11 to facilitate oil drainage and excavation. Lay a layer of HDPE membrane 111 on the side wall of the annular groove 11. Then, fill a layer of coarse sand cushion 112 into the annular groove 11 and lay a first asphalt sand cushion 113 on top of the coarse sand cushion 112. At the same time, pour a plain concrete cushion 2 into the first asphalt sand cushion 113. The top wall of the annular plain concrete cushion 2 is flush with the road base 1. The HDPE membrane 111 laid on top of the annular groove 11 and the road base 1 can prevent oil from seeping into the road base 1. The first asphalt sand cushion 113 in the annular groove 11 can not only block leakage, but also ensure the strength of the ring beam 3. The construction cost is also low.

[0033] C. Ring Beam Construction: The ring beam 3 is constructed by pouring concrete layer by layer above the plain concrete foundation 2. Each layer of ring beam 3 is poured to a height of 30-50mm. In this implementation, each layer is selected to be 50mm high. Reinforcing bars 31 are tied layer by layer, formwork is erected and reinforced, and each ring beam layer is cast integrally. Concrete is then poured and compacted layer by layer until the required construction height is achieved as shown in the drawings. The quality of the ring beam is crucial to the overall construction quality of the tank. Because the ring beam 3 is a thin-walled, ultra-long structure, it is highly susceptible to temperature and shrinkage stress. Therefore, the layer-by-layer pouring method, the thickness of the reinforcing bar 31 protective layer, and the water-cement ratio of the concrete can all lead to cracking. To prevent cracks that are detrimental to the structure, the following measures are taken:

[0034] ① Select cement with low heat of hydration for concrete preparation; ② Select coarse and fine aggregates with larger particle size and good gradation, and strictly control the mud content of sand and gravel; ③ Design a reasonable mix proportion and control the amount of cement per cubic meter; according to experiments, for every 10 kg increase or decrease in cement, the heat of hydration will cause the concrete temperature to rise or fall by 1℃; ④ Add fly ash and high-efficiency water-reducing agent to improve workability and reduce the water-cement ratio; ⑤ Add an appropriate amount of concrete expansion agent to compensate for concrete shrinkage; ⑥ Use tie bolts to reinforce the formwork to prevent grout leakage; ⑦ Strictly control the quality of concrete pouring and ensure that the concrete is vibrated and compacted; ⑧. Strictly monitor the temperature of the concrete during and after pouring of the ring beam 3 concrete. If the temperature difference between the inside and outside of the concrete is too large, cover the surface with straw bags for insulation; the temperature difference between the inside and the surface of the concrete should not exceed 25℃; strengthen the curing of the ring beam 3 concrete. After pouring, strengthen the curing of the concrete and prevent it from being exposed to direct sunlight. Cover the exposed surface with film and cotton felt in time for curing. A dedicated person shall be responsible for curing, and the curing time shall not be less than 14 days, keeping the concrete surface moist.The vertical reinforcement 31 of the ring beam 3 uses Φ12 threaded steel bars, and the circumferential reinforcement 31 uses Φ28@100 threaded steel bars, totaling four layers. The reinforcement 31 of the ring beam 3 is tied after the inner formwork is installed. When tying the outer layer of reinforcement 31, the thickness of the protective layer should be controlled, and its position should be controlled according to the position of the inner formwork to prevent the reinforcement 31 from being out of round and causing difficulties in the outer formwork erection. For the formwork selection: both the inner and outer formwork use plywood with dimensions of 1220×1700 mm and a thickness of 18 mm. To ensure that the formwork conforms as closely as possible to the curvature of the ring beam 3, [further details needed]. Plywood is placed vertically (each plywood panel is 1.22m wide). Because the inner diameter of ring beam 3 is 95.5m, which is relatively large, the error between the radius of ring beam 3 and the radius of the polygon formed by the plywood mold is 1.9mm, which can be ignored. Furthermore, the plywood is flexible and can be adjusted appropriately during reinforcement. The formwork installation sequence is as follows: first, erect the inner formwork and provide support; then, tie the reinforcing bars 31; after tying the reinforcing bars 31, erect and reinforce the outer formwork. During formwork prefabrication, nail the three vertical ribs and plywood together, leaving proper splicing edges, and secure them. Through-wall bolt holes are provided for easy assembly; Fixing the bottom of the formwork: Mark the edge lines of ring beam 3 on the foundation layer, and install the formwork according to the marked edge lines; Since the foundation trench is backfilled with crushed stone and has a gentle slope, the lower part of the formwork is difficult to support. Therefore, when pouring the foundation layer, embed a 10cm wide formwork every 1m in the foundation layer. When installing the formwork, fix the bottom with wooden clamps, which are nailed to the embedded formwork; Fixing the top of the formwork: After the formwork is corrected for verticality, it is supported firmly with diagonal braces; Φ48 steel pipes are used as diagonal braces; To ensure the stability of the support, in the crushed stone... A base plate is laid on the stone surface, and steel pipes are supported on the base plate. Wooden wedges are used to tighten the base plate and steel pipes. To ensure the stability of the diagonal bracing, vertical tie rods are installed, which are connected to the outer steel pipes at the bottom of the formwork to prevent the diagonal bracing from becoming unstable. Horizontal tie rods are also installed. When setting up the inner formwork, each formwork piece is installed according to the chalk line position, and after the verticality is corrected, it is firmly supported with diagonal bracing. After the outer formwork is reinforced with diagonal bracing, four through-wall bolts are installed at equal intervals in the vertical direction of the outer formwork. After the inner and outer formwork are installed, a total station is used to measure to check whether the shape and dimensions of the formwork meet the design requirements.

[0035] D. Backfilling construction within the ring beam: First, lay a layer of HDPE membrane 111 on the road base 1 within the ring beam 3. Then, within the ring beam 3, lay the following layers in sequence: second asphalt sand cushion layer 32 → geotextile layer 33 → graded crushed stone cushion layer 34 → HDPE membrane 111 → medium-coarse sand cushion layer 35 → multi-layered bonded foam board layer 36 → waterproof asphalt layer 37 → graded crushed stone cushion layer 34 → waterstop layer 38 → cement fiberboard layer 39 → third asphalt sand cushion layer 40 → polytetrafluoroethylene layer 41. Thus, within the ring beam 3, the layers are: HDPE membrane 111, second asphalt sand cushion layer 32, geotextile layer 33, graded crushed stone cushion layer 34, HDPE membrane 111, medium-coarse sand cushion layer 35, multi-layered bonded foam board layer 36 → waterproof asphalt layer 37 → graded crushed stone cushion layer 34 → waterstop layer 38 → cement fiberboard layer 39 → third asphalt sand cushion layer 40 → polytetrafluoroethylene layer 41. The coarse sand cushion layer 35, the multi-layered foam board layer 36, the waterproof asphalt layer 37, the graded crushed stone cushion layer 34, the waterstop layer 38, the cement fiberboard layer 39, the third asphalt sand cushion layer 40, and the polytetrafluoroethylene layer 41 can all effectively prevent oil leakage. This laying method has been tested many times and has excellent barrier effect and low construction cost. At the same time, the medium-coarse sand cushion layer 35, the graded crushed stone cushion layer 34, and the cement fiberboard layer 39 can also play a good supporting role to ensure the stability of the oil storage tank 9. The inner wall of the ring beam 3 and above the leak detection pipe 6 is also coated with a waterproof asphalt layer 37 to further prevent oil leakage.

[0036] Technical requirements for medium-coarse sand backfilling construction (1):

[0037] 1) Medium and coarse sand should be hard and contain organic impurities, with a mud content not exceeding 5%, and silt should not be used; 2) The compaction coefficient of the medium and coarse sand cushion layer 35 should not be less than 0.96; 3) Medium sand: sand with a particle size greater than 0.25mm and less than 0.5mm containing more than 50% of the total weight; 4) Coarse sand: sand with a particle size greater than 0.5mm and less than 2mm containing more than 50% of the total weight.

[0038] The sand cushion layer is laid in layers and backfilled according to the designed thickness. It is compacted with a plate vibrator for 8-10 passes. During construction, water is sprinkled to keep the sand moisture content at about 15%-20%. The number of passes is tested by sampling with a ring cutter, and the compaction coefficient λ≥0.96. When moving the vibrator, each row overlaps by one-third to prevent missed vibration. During construction, auxiliary steel bars are driven in every 2m as elevation control points to control the elevation of the sand cushion layer. After construction, the surface elevation is re-measured, and the flatness is checked by string line. Any areas that are too high are leveled, and any areas that are too low are filled. The surface is then compacted with a plate vibrator to prepare for the construction of the asphalt sand insulation layer. When laying the sand cushion layer, the virtual height is calculated, and attention is paid to reserving the compaction thickness.

[0039] The geotextile layer 33 is laid manually by rolling; the surface of the geotextile should be flat and leave appropriate deformation allowance. The geotextile is installed by heat bonding or sewing. The HDPE membrane 111 is bonded together with waterproof adhesive at the joints to prevent oil leakage. The cement fiberboard layers 39 are also bonded together with waterproof adhesive to prevent oil leakage.

[0040] E. Backfilling construction outside the ring beam: Lay a layer of HDPE film 111 on the inner and outer road base layer 1 of the ring beam 3, and lay the second asphalt sand cushion layer 32 → medium and coarse sand cushion layer 35 → concrete pavement layer 5 layer by layer outside the ring beam 3.

[0041] F. Complete the overall construction of the ring beam and hand it over.

[0042] Reference Figures 1-2 As shown, the construction of the ring beam 3 in step C also includes: pouring concrete in the same direction from the same point and simultaneously pouring in the opposite direction until the concrete of that layer is poured. The backfilling construction in the ring beam 3 in step D also includes: the waterstop layer 38, cement fiberboard layer 39, third asphalt sand cushion layer 40 and polytetrafluoroethylene layer 41 in the ring beam 3 are all inclined downwards at 9-12 degrees from the center of the ring beam 3 to the surrounding areas. In this embodiment, the inclination angle from the center of the ring beam 3 to the surrounding areas is 11 degrees. This allows oil to be introduced into the annular groove 11 when oil leakage occurs, which is convenient for later cleaning and saves costs.

[0043] Reference Figure 1 As shown, a geomembrane 51 is laid between the concrete pavement layer 5 outside the ring beam 3 and the second asphalt sand cushion layer 32, and within the medium-coarse sand cushion layer 35. The geomembrane 51 is attached to the ring beam 3 and has an L-shaped cross-section. The geomembrane 51 can effectively prevent oil leakage. Multiple leak detection pipes 6 are connected circumferentially around the ring beam 3. One end of the leak detection pipe 6 extends into the graded crushed stone cushion layer 34 above the waterproof asphalt layer 37 inside the ring beam 3, and the other end extends outside the ring beam 3. The leak detection pipe 6 is inclined. By checking whether the leak detection pipe 6 is leaking oil, it is easy to check whether the oil storage tank 9 is leaking oil. The operation is very simple and convenient. In summary, the construction method can effectively prevent oil from leaking into the soil, avoid environmental pollution and economic losses, and improve the service life of the overall ring beam 3 and oil storage tank 9.

[0044] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for constructing a concrete foundation ring beam for a large oil storage tank, characterized in that: Includes the following steps: A. Construction preparation: Survey and clean the construction site, level the site, use instruments such as total station and precision level to conduct construction measurement and positioning according to the drawing data, and use paint to draw lines in the fixed points and positioning areas, and draw the projection area of ​​the ring beam (3) on the road base (1) specified on the construction drawings. B. Excavation and backfilling of tank foundation: First, excavate an annular groove (11) on the road base (1) and directly below the ring beam (3). The cross section of the annular groove (11) is trapezoidal. Lay a layer of HDPE film (111) on the side wall of the annular groove (11). Then, fill a layer of coarse sand cushion (112) into the annular groove (11). Lay a first asphalt sand cushion (113) on top of the coarse sand cushion (112). At the same time, pour a plain concrete cushion (2) into the first asphalt sand cushion (113). The top wall of the annular plain concrete cushion (2) is flush with the road base (1). C. Ring beam construction: The ring beam (3) is poured on the plain concrete cushion layer (2) by pouring concrete layer by layer. The pouring height of each ring beam (3) is 30-50mm. The reinforcing bars (31) are tied layer by layer, the formwork is erected and reinforced, and each ring beam (3) is poured into shape as a whole. The concrete is poured layer by layer and vibrated to compact until the required construction height in the drawings is reached. D. Backfilling construction inside the ring beam: First, lay a layer of HDPE membrane (111) on the road base (1) inside the ring beam (3), and then lay the second asphalt sand cushion layer (32) → geotextile layer (33) → graded crushed stone cushion layer (34) → HDPE membrane (111) → medium and coarse sand cushion layer (35) → multi-layer inter-bonded foam board layer (36) → waterproof asphalt layer (37) → graded crushed stone cushion layer (34) → waterstop layer (38) → cement fiber board layer (39) → third asphalt sand cushion layer (40) → polytetrafluoroethylene layer (41) in the ring beam (3). E. Backfilling construction outside the ring beam: Lay a layer of HDPE film (111) on the road base (1) outside the ring beam (3), and lay the second asphalt sand cushion layer (32) → medium and coarse sand cushion layer (35) → concrete pavement layer (5) layer by layer outside the ring beam (3); F. Complete the overall construction of the ring beam (3) and hand it over.

2. The construction method for the concrete foundation of the ring beam of a large oil storage tank according to claim 1, characterized in that: The backfilling construction outside the ring beam described in step E also includes: laying a geomembrane (51) between the concrete pavement layer (5) outside the ring beam (3) and the second asphalt sand cushion layer (32) and inside the medium-coarse sand cushion layer (35). The geomembrane (51) is attached to the ring beam (3) and the cross section of the geomembrane (51) is 'L' shaped.

3. The construction method for the concrete foundation of the ring beam of a large oil storage tank according to claim 1, characterized in that: The ring beam (3) is circumferentially connected with multiple leak detection tubes (6). One end of the leak detection tube (6) extends into the graded crushed stone cushion layer (34) above the waterproof asphalt layer (37) inside the ring beam (3), and the other end extends out of the ring beam (3). The leak detection tube (6) is inclined.

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