Large-diameter hollow sandwich steel pipe based on load balancing method

Abstract

The application discloses a large-diameter hollow sandwich steel pipe based on a load balancing method. The hollow sandwich steel pipe is assembled in sections along the axial direction, and adjacent sections are welded to form the pipe. The hollow sandwich steel pipe comprises an outer steel pipe, an inner steel pipe and a tension bolt arranged between the outer steel pipe and the inner steel pipe. The inner wall of the outer steel pipe and the outer wall of the inner steel pipe form a channel one, and the inner wall of the inner steel pipe forms a channel two. The water flow in the channel one and the water flow in the channel two are combined before a turbine. The tension bolt is used to connect the inner and outer steel pipes, so that the inner and outer steel pipes bear the load together. The water pressure in the channel one is used to eliminate part of the water pressure in the channel two, so that the load effect of part or all of the pipe is offset. The application can effectively reduce the wall thickness of the steel pipe, reduce the strength of the steel, save the material consumption, reduce the engineering cost and has good economic benefits.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of pressure conduit of pumped storage power station, and particularly relates to a large-diameter hollow sandwich steel pipe conduit based on load balancing method. BACKGROUND

[0002] As an important part of pumped storage power station, the pressure conduit is also the core channel of energy conversion, and its stability in safe operation is crucial.

[0003] The traditional pressure conduit is mainly steel pipe, which has high strength and good impermeability. However, with the application of large-megawatt pumped storage power station, the steel pipe bears greater internal water pressure during operation, greatly increasing the steel pipe wall thickness and steel strength, improving the construction cost, and increasing the construction difficulty due to the excessive weight of the steel pipe, which greatly restricts the promotion and application of the steel pipe pressure conduit. SUMMARY

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a large-diameter hollow sandwich steel pipe conduit based on load balancing method, so as to offset part or all of the pipe load effect, reduce the steel pipe wall thickness and steel strength, and save the material consumption.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0006] A large-diameter hollow sandwich steel pipe conduit based on load balancing method is composed of a plurality of hollow sandwich steel pipe segments assembled along the axial direction, each of which comprises an outer steel pipe, an inner steel pipe and a tension bolt, and the tension bolt is arranged between the outer steel pipe and the inner steel pipe. Wherein, a channel one is formed between the inner wall of the outer steel pipe and the outer wall of the inner steel pipe; a channel two is formed in the inner steel pipe, and the external water pressure in the channel one can eliminate part or all of the internal water pressure in the channel two, so as to offset part or all of the pipe load effect.

[0007] In one embodiment, the conduit serves as the pressure conduit of megawatt pumped storage power station, and the external water flow in the channel one and the internal water flow in the channel two are combined before the turbine.

[0008] In one embodiment, the tension bolt is a high-strength bolt, and is arranged at equal intervals along the circumferential direction and the axial direction of the conduit.

[0009] In one embodiment, one end of the tension bolt is welded to the outer wall of the inner steel pipe, and the other end is welded to the inner wall of the outer steel pipe, and the length direction is radial.

[0010] In one embodiment, one end of the tension bolt is welded to the outer wall of the inner steel pipe, and the other end passes through the outer steel pipe and is provided with a mounting nut on the outer wall of the outer steel pipe; or,

[0011] One end of the pair of pull bolts is welded to the inner wall of the outer steel pipe, and the other end passes through the inner steel pipe and sets a mounting nut on the inner wall of the inner steel pipe; or,

[0012] One end of the pair of pull bolts passes through the outer steel pipe and sets a mounting nut on the outer wall of the outer steel pipe, and the other end passes through the inner steel pipe and sets a mounting nut on the inner wall of the inner steel pipe.

[0013] In one embodiment, a concrete lining is arranged between the hollow sandwich steel pipe section and the rock mass.

[0014] In one embodiment, the pouring mode of the concrete lining is cast-in-place, and the concrete lining is ordinary concrete, high-strength concrete, recycled concrete or self-compacting concrete.

[0015] In one embodiment, the length of each hollow sandwich steel pipe section is 2-4m, the outer diameter of the outer steel pipe is not less than 8m, the inner diameter of the inner steel pipe is not less than 6m and not more than 10m, and the ratio of the axial spacing of the pair of pull bolts to the wall thickness of the outer steel pipe is not less than 50.

[0016] In one embodiment, the wall thickness of the outer steel pipe and the inner steel pipe is not less than 20mm and not more than 40mm.

[0017] Compared with the prior art, the beneficial effects of the present application are:

[0018] 1) Convenient construction

[0019] The large-diameter hollow sandwich steel pipe pipeline based on the load balance method has a simple structure, is assembled along the axial direction, and is welded to form a pipeline. The pipeline components are standardized in the factory, which ensures the construction quality, reduces the construction difficulty, and greatly improves the construction performance.

[0020] 2) Performance improvement

[0021] The large-diameter hollow sandwich steel pipe pipeline based on the load balance method uses a pair of pull bolts to connect the inner and outer steel pipes, increases the pipeline stiffness, prevents local buckling of the steel pipe, improves the stability of the steel pipe, and realizes common stress of the inner and outer steel pipes.

[0022] 3) Design flexibility

[0023] The large-diameter hollow sandwich steel pipe pipeline based on the load balance method utilizes the outer water pressure in the passage one to eliminate the inner water pressure in the passage two, which can effectively reduce the steel pipe wall thickness and the steel strength, save the material consumption, reduce the engineering cost, and has good economic benefits.

[0024] Overall, the large diameter hollow sandwich steel pipe pipeline based on load balancing method adopts the pull bolt to connect the inner and outer steel pipes, realizes the common stress of the inner and outer steel pipes, eliminates part of the water pressure in the passage two by using the water pressure in the passage one, and realizes the purpose of offsetting part or all of the pipeline use load effect. The application can effectively reduce the steel pipe wall thickness and reduce the steel strength, save the material consumption, reduce the engineering cost, and has good economic benefits. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a whole schematic view of a large diameter hollow sandwich steel pipe pipeline based on load balancing method of the application.

[0026] Figure 2 is a sectional schematic view of a large diameter hollow sandwich steel pipe pipeline based on load balancing method of the application.

[0027] Figure 3 is a sectional schematic view of a second large diameter hollow sandwich steel pipe pipeline based on load balancing method of the application.

[0028] Figure 4 is a sectional schematic view of a third large diameter hollow sandwich steel pipe pipeline based on load balancing method of the application.

[0029] Figure legend: 1-large diameter hollow sandwich steel pipe pipeline; 2-outer steel pipe; 3-inner steel pipe; 4-pull bolt; 5-passage one 5; 6-passage two 6; 7-mounting nut; 8-rock mass; 9-concrete lining. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme of the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0031] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present application.

[0032] It should be noted that: similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0033] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product is usually placed, only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0034] As shown in Figures 1-4 The present application is a large-diameter hollow sandwich steel pipe pipeline based on load balancing method. The pipeline is composed of several hollow sandwich steel pipe segments 1 assembled in the axial direction. Each hollow sandwich steel pipe segment 1 mainly includes an outer steel pipe 2, an inner steel pipe 3 and a tension bolt 4, wherein the tension bolt 4 is arranged between the outer steel pipe 2 and the inner steel pipe 3. At this time, a passage one 5 is formed between the inner wall of the outer steel pipe 2 and the outer wall of the inner steel pipe 3; and a passage two 6 is formed in the inner steel pipe 3. In the present application, the outer water pressure in the passage one 5 should be able to eliminate part or all of the inner water pressure in the passage two 6, thereby offsetting part or all of the pipeline use load effect.

[0035] In the present application, in the first aspect, the pipeline is formed by assembling a plurality of hollow sandwich steel pipe segments 1 in the axial direction through connection methods such as welding, which has a simple structure, each hollow sandwich steel pipe segment 1 can be prefabricated in the factory, and the construction difficulty is low and the efficiency is high. In the second aspect, the outer steel pipe 2 and the inner steel pipe 3 are connected by the tension bolt 4, which can greatly improve the pipeline stiffness and prevent local buckling, and the outer steel pipe 2 and the inner steel pipe 3 bear forces together, thereby improving the overall stability of the pipeline. In the third aspect, the outer water pressure in the passage one 5 is used to eliminate part or all of the inner water pressure in the passage two 6, which can greatly reduce the steel pipe wall thickness, save material consumption, reduce the requirement for steel strength, and reduce the engineering cost.

[0036] In the present application, the length of each hollow sandwich steel pipe segment 1 is about 2-4m, the outer diameter of the outer steel pipe 2 is not less than 8m, the inner diameter of the inner steel pipe 3 is not less than 6m and not more than 10m, and the ratio of the axial spacing of the tension bolt 4 to the wall thickness of the outer steel pipe 2 is not less than 50.

[0037] According to Table 4.4.1 of GB 50017-2017 "Steel Structure Design Standard", the more the steel thickness increases, the more the steel strength design value is reduced. In the present application, the wall thickness of the outer steel pipe 2 and the inner steel pipe 3 is not less than 20mm and not more than 40mm, so the reduction of the steel strength design value can be effectively reduced, the steel strength can be fully utilized, and the pipeline wall thickness can be reduced.

[0038] In one embodiment of the present application, the large-diameter hollow sandwich steel pipe pipeline of the present application is mainly used for the pressure pipeline of a megawatt pumped storage power station, and the outer water flow in the passage one 5 and the inner water flow in the passage two 6 are combined before the turbine.

[0039] In the embodiment, when the large-diameter hollow sandwich steel pipe is used as a pressure pipe of a megawatt pumped storage power station, based on the principle of load balance method, the outer water pressure in the passage one 5 is used to eliminate part or all of the inner water pressure in the passage two 6, so as to offset part or all of the pipe use load effect, reduce the steel pipe wall thickness and reduce the steel strength, and save the material amount. Compared with the traditional pressure steel pipe, the hollow sandwich steel pipe can effectively avoid the steel strength reduction, fully play the steel strength, and improve the steel utilization rate.

[0040] In one embodiment of the present application, the pull bolt 4 is a high-strength bolt, and is arranged at equal intervals along the circumferential direction and the axial direction of the pipe, and the length direction is the radial direction.

[0041] In the embodiment, the pull bolt 4 is arranged in this way, which aims to prevent local buckling of the inner and outer steel pipes, and at the same time connect the inner and outer steel pipes to form a hollow sandwich steel pipe structure, improve the overall structure, and realize common stress.

[0042] In one embodiment of the present application, as shown in Figure 2 , one end of the pull bolt 4 is welded to the outer wall of the inner steel pipe 3, and the other end is welded to the inner wall of the outer steel pipe 2.

[0043] In one embodiment of the present application, as shown in Figure 3 , one end of the pull bolt 4 is welded to the outer wall of the inner steel pipe 3, and the other end is welded to the inner wall of the outer steel pipe 2.

[0044] In one embodiment of the present application, as shown in Figure 4 , one end of the pull bolt 4 is welded to the outer wall of the inner steel pipe 3, and the other end is welded to the inner wall of the outer steel pipe 2.

[0045] In one embodiment of the present application, the hollow sandwich steel pipe section 1 and the rock mass 8 are provided with a concrete lining 9, and the pouring mode of the concrete lining 9 is cast-in-place, which can be ordinary concrete, high-strength concrete, recycled concrete or self-compacting concrete, etc., to meet different requirements of actual engineering for concrete performance.

[0046] In the embodiment, as an important component of the water conveying structure of the pumped storage power station, the buried pressure pipe is mostly installed in the excavated tunnel in the form of steel lining, and the steel lining and the surrounding rock are jointly stressed by filling concrete between the steel lining and the surrounding rock, so as to reduce the thickness of the steel lining and reduce the cost.

[0047] The above merely provides preferred embodiments of the present application, and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the principles and technical scope of the present application shall fall into the scope of the present application.

Claims

1. A large-diameter hollow sandwich steel pipe based on the load balance method, characterized in that, The system is constructed by assembling several hollow sandwich steel pipe sections (1) along the axial direction. Each hollow sandwich steel pipe section (1) includes an outer steel pipe (2), an inner steel pipe (3), and tie bolts (4). The tie bolts (4) are located between the outer steel pipe (2) and the inner steel pipe (3). A channel one (5) is formed between the inner wall of the outer steel pipe (2) and the outer wall of the inner steel pipe (3). A channel two (6) is formed inside the inner steel pipe (3). The external water pressure in the channel one (5) can eliminate part or all of the internal water pressure in the channel two (6), thereby offsetting part or all of the pipeline's load effect. The pipeline serves as a pressure pipeline for a megawatt-level pumped storage power station. The external water flow in the channel one (5) and the internal water flow in the channel two (6) converge in front of the turbine. The tie bolts (4) are high-strength bolts and are arranged at equal intervals along the circumferential and axial directions of the pipe; One end of the tie bolt (4) is welded to the outer wall of the inner steel pipe (3), and the other end is welded to the inner wall of the outer steel pipe (2), with its length direction being radial; or, One end of the tie bolt (4) is welded to the outer wall of the inner steel pipe (3), and the other end passes through the outer steel pipe (2) and is fitted with a mounting nut (7) on the outer wall of the outer steel pipe (2); or, One end of the tie bolt (4) is welded to the inner wall of the outer steel pipe (2), and the other end passes through the inner steel pipe (3) and a mounting nut (7) is provided on the inner wall of the inner steel pipe (3); or, One end of the tie bolt (4) passes through the outer steel pipe (2) and a mounting nut (7) is provided on the outer wall of the outer steel pipe (2), and the other end passes through the inner steel pipe (3) and a mounting nut (7) is provided on the inner wall of the inner steel pipe (3). A concrete lining (9) is provided between the hollow interlayer steel pipe section (1) and the rock mass (8). The concrete lining (9) is cast in place, and the concrete lining (9) is ordinary concrete, high-strength concrete, recycled concrete or self-compacting concrete. The length of each hollow sandwich steel pipe section (1) is 2-4m, wherein the outer diameter of the outer steel pipe (2) is not less than 8m, and the inner diameter of the inner steel pipe (3) is not less than 6m and not more than 10m; the ratio of the axial spacing of the tie bolts (4) to the wall thickness of the outer steel pipe (2) is not less than 50. The wall thickness of the outer steel pipe (2) and the inner steel pipe (3) is not less than 20 mm and not more than 40 mm.

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