Stiffening ring for in-hole pressure steel pipe

Abstract

The utility model discloses a stiffening ring for a pressure steel pipe in a hole, which belongs to the technical field of large pressure steel pipes for water conservancy and hydropower and comprises an arc-shaped ring body, the arc-shaped ring body comprises an inner ring body, a middle ring body and an outer ring body, and the thickness of the inner ring body and the thickness of the outer ring body are both larger than that of the middle ring body. The middle ring body is integrally formed between the inner ring body and the outer ring body; the inner ring body is provided with a binding face matched with the outer wall of the pressure steel pipe, inclined welding grooves are symmetrically formed in the two sides of the binding face, and the inner ring body can form a welding groove in the pressure steel pipe through the welding grooves. The technical problems that in the prior art, a stiffening ring occupies much operation space in a tunnel and the welding workload of the stiffening ring is large are effectively solved, the construction efficiency and the operation convenience can be remarkably improved, and the civil engineering excavation cost of the tunnel is effectively reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of large-scale penstocks for water conservancy and hydropower projects, and particularly relates to a stiffening ring for penstocks in tunnels. Background Art

[0002] Among many large-scale water conservancy and hydropower projects built in high mountain valleys, penstocks are often arranged inside tunnels. Given the particularity of the tunnel construction environment, penstocks need to be fabricated in sections, transported into the tunnel, and then transferred to the designated positions for assembly one by one. During this process, sufficient passageways and working spaces are required for welding operations of the welds between pipe sections and for personnel to enter and exit. Considering the difficulties involved in long tunnel construction, the huge amount of work, and cost control, etc., during civil engineering excavation, the tunnel diameter is often kept within the minimum necessary range. Penstocks, with their excellent strength and sealing performance, can effectively bear the internal water pressure. Without additional thickening of the main pipe wall, by introducing a stiffening ring, a ring-shaped strengthening structure welded to the outside of the steel pipe, the stability of the steel pipe against external pressure is significantly enhanced. Therefore, when transporting the penstock and its external stiffening ring into the tunnel for welding operations of the welds between pipe sections, it is inevitably necessary to effectively coordinate the working space between the diameter of the tunnel civil engineering excavation and the outer diameter of the steel pipe.

[0003] In the prior art, as Figures 1-3 shown, a rectangular-section stiffening ring 3 is welded to the outside of the wall of the penstock 1. Among them, Figure 3 the C-C cross-section shows the rectangular cross-sectional shape of the rectangular-section stiffening ring 3. The rectangular-section stiffening ring 3 is firmly welded to the wall of the penstock 1 through the fillet weld points 4, and its manufacturing process is to directly cut the steel plate and bend it into shape. Taking Figure 1 and Figure 3 as examples, to ensure the structural strength of the penstock 1 when bearing the pressure of the internal flowing medium (such as water flow), the design of the rectangular-section stiffening ring 3 needs to consider matching the diameter of the penstock 1. Specifically, the rectangular cross-section of the rectangular-section stiffening ring 3 needs to reach a certain flexural modulus standard. For example, for a penstock 1 with a specific diameter, the flexural modulus standard of the rectangular cross-section in the rectangular-section stiffening ring 3 is 2.874667×10 -4 m 4 . To achieve this flexural modulus, the outer diameter L0 of its cross-section needs to reach at least 280 mm, and the cross-section thickness (the width from left to right along the Figure 3 shown direction) needs to reach at least 22 mm, and the corresponding cross-sectional area is 6.116×10 -3 m 2 . However, such a structure and size configuration still have the following technical problems:

[0004] 1. The size and structure of the above stiffening ring are still relatively large. In actual applications, due to the limited welding operation space in the tunnel, there is a problem that the welding operation is inconvenient.

[0005] 2. Since the stiffening ring and the penstock are arranged at a right angle, during the welding operation, the weld material can only be welded at the right-angle position and cannot penetrate between the stiffening ring and the penstock. If the welding is to be ensured to be firm, more weld material is required, which correspondingly leads to a large workload, long time, low efficiency, and high cost.

[0006] Therefore, there is an urgent need to design a stiffening ring with an optimized structure, which can reduce its occupation in the narrow operation space of the tunnel and reduce the welding workload between the stiffening ring and the penstock while maintaining the same material consumption and bending resistance as the existing technology, thereby significantly improving the construction efficiency and operation convenience. Utility Model Content

[0007] The purpose of the present utility model is to solve the above problems existing in the prior art, and provides a stiffening ring for the penstock in the tunnel. Through the combined structure of the inner ring body, the middle ring body, and the outer ring body forming an arc-shaped ring body, the design that the thicknesses of the inner ring body and the outer ring body are both greater than the thickness of the middle ring body, and the use of inclined welding grooves symmetrically arranged on both sides of the fitting surface of the inner ring body, the technical problems that the stiffening ring in the prior art occupies a large amount of operation space in the tunnel and has a large welding workload of the stiffening ring are effectively solved, the welding operation difficulty of the pipe joint weld by construction workers in the tunnel is reduced, and the convenience of operation and passage of construction workers in the tunnel is increased; at the same time, the welding workload of the stiffening ring is also reduced, thereby significantly improving the production efficiency.

[0008] To achieve the above purpose, the technical solution adopted by the present utility model is as follows:

[0009] The stiffening ring for the penstock in the tunnel of the present utility model includes an arc-shaped ring body, and the arc-shaped ring body includes an inner ring body, a middle ring body, and an outer ring body. The thicknesses of the inner ring body and the outer ring body are both greater than the thickness of the middle ring body, and the middle ring body is integrally formed between the inner ring body and the outer ring body; the inner ring body has a fitting surface adapted to the outer wall of the penstock, and inclined welding grooves are symmetrically arranged on both sides of the fitting surface. The inner ring body can form a welding groove on the penstock through the welding grooves.

[0010] The thickness of the outer ring body is greater than or equal to the thickness of the inner ring body.

[0011] The number of the middle ring bodies is at least one. When the number of the middle ring bodies is one, the middle ring body is connected to the middle part between the inner ring body and the outer ring body, and the stiffening ring has an I-shaped cross-section; when the number of the middle ring bodies is two, the middle ring bodies are connected between the inner ring body and the outer ring body, and the stiffening ring has a square-shaped cross-section; the middle ring body and the inner ring body are in arc transition, and the middle ring body and the outer ring body are in arc transition.

[0012] The cross-section of the middle ring body is rectangular. An inner convex part facing the inner ring body is arranged in the middle of the inner side of the outer ring body, and an outer convex part facing the outer ring body is arranged in the middle of the outer side of the inner ring body. The middle ring body is located between the inner ring body and the outer ring body.

[0013] The cross-section of the middle ring body is frustum-shaped, and the thickness of the middle ring body increases in sequence along the direction from the outer ring body to the inner ring body.

[0014] The extended surface of the welding groove and the joint surface of the inner ring body has an included angle of 45°-55°.

[0015] The outer diameter of the cross-section of the arc ring body is 200 mm.

[0016] The advantages of adopting the utility model are as follows:

[0017] 1. In the utility model, firstly, through the combined structure of the inner ring body, the middle ring body and the outer ring body to form an arc ring body, and the design that the thicknesses of the inner ring body and the outer ring body are both greater than the thickness of the middle ring body, not only the high bending resistance performance is maintained, but also the outer diameter of the cross-section of the arc ring body is significantly reduced. This design greatly reduces the occupation of the narrow operation space of the tunnel, reduces the operation difficulty of the construction personnel for welding the pipe joint welds in the limited space, and at the same time improves the comfort, convenience and safety of the personnel passing through in the tunnel.

[0018] Secondly, compared with Figures 1-3 the existing technology shown, the combined structure of the inner ring body, the middle ring body and the outer ring body to form an arc ring body adopted by the utility model, and the design that the thicknesses of the inner ring body and the outer ring body are both greater than the thickness of the middle ring body. In view of the relatively small contribution of the middle ring body to improving the overall moment of inertia, by increasing the cross-sectional areas of the inner ring body and the outer ring body, the overall structural performance of the arc ring body is effectively compensated. Therefore, on the premise of the same material consumption, this design not only ensures the high bending resistance performance of the stiffening ring structure, but also realizes the reduction of the outer diameter, and at the same time avoids the material consumption caused by simply reducing the outer diameter of the cross-section of the rectangular-section stiffening ring and increasing the cross-sectional thickness. Therefore, while fully ensuring the structural strength and bending resistance performance of the stiffening ring, the utility model also realizes the saving of the material cost, reflecting the high efficiency and economy in the design.

[0019] In addition, the design of integrally forming the middle ring body between the inner ring body and the outer ring body ensures the integrity of the arc-shaped ring body, improving the durability and reliability of the entire stiffening ring in complex engineering environments. At the same time, due to the structural integrity of the inner ring body, middle ring body, and outer ring body, the manufacturing process flow is optimized, enhancing the convenience during bending and splicing installation, and further ensuring production efficiency.

[0020] Finally, the design of welding grooves that are symmetrical and inclined on both sides of the fitting surface of the inner ring body forms a welding groove when the inner ring body is closely attached to the outer wall of the penstock. Compared with the fillet weld points in the prior art, the amount of weld material is significantly reduced, lowering the manufacturing cost. At the same time, this design greatly reduces the labor intensity of welders during the welding and fixing process of the stiffening ring and the penstock, significantly improving the overall production efficiency.

[0021] 2. In the present utility model, through the structural design where the thickness of the outer ring body is greater than or equal to the thickness of the inner ring body, when facing high-pressure media (such as water flow) inside the penstock, the pressure is sequentially transmitted through the inner ring body, middle ring body, and outer ring body, and finally evenly distributed to the surrounding concrete structure. The close cooperation between the stiffening ring and the concrete jointly constructs a high-strength and highly reliable pressure-bearing structure, promoting the coordination and strengthening of the overall structure, and significantly enhancing the reliability and durability of the structure.

[0022] 3. In the present utility model, through the arc transition connection design of the inner ring body, middle ring body, and outer ring body, it helps to enhance the stability and stiffness of the stiffening ring, enabling it to better resist external pressure and deformation. Further, through the flexible design of the number of middle ring bodies, while maintaining the same outer diameter as the rectangular cross-section in the prior art, the flexural modulus of the stiffening ring in the present utility model can be increased; or while maintaining the same flexural modulus as the rectangular cross-section in the prior art, the cross-sectional outer diameter and material usage of the stiffening ring in the present utility model can be reduced. This design increases the adaptability of the stiffening ring. While ensuring high flexural performance, it realizes cost savings through reasonable material layout and improves production efficiency.

[0023] 4. In the present utility model, through the design where the cross-section of the middle ring body is rectangular, there is an inner protrusion on the middle part of the inner side of the outer ring body facing the inner ring body, and an outer protrusion on the middle part of the outer side of the inner ring body facing the outer ring body, the I-shaped cross-section shape is optimized. On the premise of maintaining the same cross-sectional area and material usage as the rectangular cross-section in the prior art, the flexural performance is not lower than or even slightly better than that of the rectangular cross-section in the prior art. More importantly, the reduction of the overall cross-sectional outer diameter is more conducive to the pipe joint welding and installation operation of the penstock in the narrow space inside the tunnel. For the construction of long tunnels, it helps to reduce the civil engineering excavation cost.

[0024] In addition, if the I-shaped cross-section is designed to have the same outer diameter as the rectangular cross-section in the prior art, its bending resistance and stability will be significantly improved. This potential advantage not only enhances the resistance of the stiffening ring under extreme working conditions but also provides a more solid guarantee for the safety and durability of the tunnel project.

[0025] 5. In the present utility model, the cross-section of the middle ring body is frustum-shaped, and the thickness of the middle ring body increases successively from the outer ring body to the inner ring body. By deforming the I-shaped cross-section, while keeping the cross-sectional area and material consumption the same as those of the rectangular cross-section in the prior art, this design not only significantly reduces the outer diameter of the deformed I-shaped cross-section but also remarkably improves its flexural modulus. If the flexural modulus of the deformed I-shaped cross-section is designed to be the same as that of the rectangular cross-section in the prior art, the outer diameter of the deformed I-shaped cross-section can be further reduced, which not only further optimizes the occupation of the welding operation space in the tunnel, improves the construction efficiency, but also saves the material cost.

[0026] 6. In the present utility model, by controlling the angle formed by the extension surface of the welding groove and the mating surface of the inner ring body within the range of 45° - 55°, the welding quality and welding efficiency are further improved, and the stability of the stiffening ring on the penstock is enhanced.

[0027] 7. In the present utility model, compared with the Figure 3 rectangular cross-section, by precisely controlling the outer diameter of the cross-section of the arc-shaped ring body to be 200 mm, while maintaining high bending resistance performance and the same material consumption, the outer diameter of the stiffening ring cross-section is significantly reduced, the occupation of the narrow operation space in the tunnel is reduced, the operation difficulty of the construction personnel for welding the pipe joint welds in the limited space is reduced, and the construction efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic structural diagram of a penstock and a rectangular cross-section stiffening ring in the prior art;

[0029] Figure 2 is a schematic A-A cross-sectional structural diagram of a penstock and a rectangular cross-section stiffening ring in the prior art;

[0030] Figure 3 is a schematic C-C cross-sectional structural diagram of a penstock and a rectangular cross-section stiffening ring in the prior art;

[0031] Figure 4 is a schematic structural diagram of a penstock and a stiffening ring in the present utility model;

[0032] Figure 5 is a schematic A-A cross-sectional structural diagram of a penstock and a stiffening ring in the present utility model;

[0033] Figure 6 Schematic diagram of the C-C plane structure of the penstock and the stiffening ring with an I-shaped cross-section in the present utility model;

[0034] Figure 7 Schematic diagram of the deformed structure of the I-shaped cross-section in the present utility model;

[0035] Figure 8 Schematic diagram of the structure of the square cross-section in the present utility model.

[0036] The reference numerals in the figure are: 1, penstock; 2, stiffening ring; 21, inner ring body; 22, middle ring body; 23, outer ring body; 3, stiffening ring with a rectangular cross-section; 4, fillet weld points; 5, welding groove; 50, welding slot. Detailed implementation manners

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present utility model clearer, the technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. For the convenience of description, the relative positional relationships of the components are all described according to the layout of the drawings in the specification. For example, the positional relationships such as front, rear, upper, lower, left, and right are determined according to the layout direction of the drawings in the specification.

[0038] Embodiment 1

[0039] As Figures 4-8 shown, the stiffening ring 2 for the penstock in the tunnel of the present utility model includes an arc-shaped ring body. The arc-shaped ring body includes an inner ring body 21, a middle ring body 22, and an outer ring body 23. The thicknesses of the inner ring body 21 and the outer ring body 23 are both greater than the thickness of the middle ring body 22, and the middle ring body 22 is integrally formed between the inner ring body 21 and the outer ring body 23. It should be particularly noted here that the "thickness" mentioned in the "Detailed implementation manners" part of this specification is taken as an example in the direction shown in any one of the Figures 6-8 accompanying drawings, specifically referring to the width from left to right, and the subsequent descriptions will be based on this.

[0040] The design of integrally forming the middle ring body 22 between the inner ring body 21 and the outer ring body 23 not only significantly improves the integrity of the structure, but also deeply considers the characteristics of the rolling process, enabling the special-shaped cross-section stiffening ring to be directly rolled through a precision mold to achieve efficient manufacturing of integral forming. During the rolling process, the straight special-shaped cross-section profiles are precisely shaped, and then these profiles can be flexibly bent into a circular arc by using a section steel bending machine or pressed by a press to form the required arc-shaped ring body. In addition, considering the huge size of the penstock for hydropower stations and the adaptability requirements with the bending equipment, the number of arc-shaped ring bodies installed on the penstock is at least two. The specific construction and assembly procedures are usually as follows: Before the penstock enters the tunnel, at least two matching arc-shaped ring bodies are pre-welded on the outer wall of the penstock by an automatic submerged arc welding device. Subsequently, these arc-shaped ring bodies are accurately assembled and spliced along the circumferential direction, and manual welding is supplemented at the splicing joint to finally form a complete and stable circular ring structure, thus successfully completing the pre-installation work.

[0041] As Figures 6-8 shown, the inner ring body 21 has a fitting surface adapted to the outer wall of the penstock. Welding grooves 5 are symmetrically arranged on both sides of the fitting surface in an inclined shape. The inner ring body can form a welding groove 50 on the penstock through the welding groove 5. That is to say: both sides of the fitting surface of the inner ring body 21 are symmetric inclined surfaces, and the inclined surfaces form an angle with the extension surface of the fitting surface, and the welding groove 50 is formed between the angle and the outer wall of the penstock 1. In addition, in the initial manufacturing stage of the arc-shaped ring body structure of the present utility model when it is in the form of a straight section steel, special equipment such as a groove milling machine can be used to pre-process the welding groove 5. Preferably, the welding groove 5 has an angle of 45° - 55° with the extension surface of the fitting surface of the inner ring body 21. The design of using the welding groove 5 not only saves the amount of weld material filling, but also greatly reduces the workload of welding construction personnel and improves the operation efficiency.

[0042] In practical applications, when the penstock is facing high-pressure media (such as water flow) inside, the inner ring body 21, the middle ring body 22, the outer ring body 23 in the stiffening ring and the concrete cooperate with each other to jointly form a high-strength and highly reliable pressure-bearing structure. Therefore, the thickness of the outer ring body 23 is preferably greater than the thickness of the inner ring body 21, and at least should be equal to the thickness of the inner ring body 21. In addition, the structural material of the stiffening ring of the present utility model is preferably Q355B steel to withstand the high pressure inside the penstock 1, ensuring the durability and reliability of the stiffening ring.

[0043] Furthermore, the number of the middle annular bodies 22 is at least one. When the number of the middle annular bodies 22 is one, the middle annular body 22 is connected to the middle part between the inner annular body 21 and the outer annular body 23, and the stiffening ring has an I-shaped cross-section; when the number of the middle annular bodies 22 is two, the middle annular bodies 22 are connected between the inner annular body 21 and the outer annular body 23, and the stiffening ring has a mouth-shaped cross-section.

[0044] It should be noted that, on the premise of ensuring that the cross-sectional area of the stiffening ring 2 is equivalent to the rectangular cross-sectional area in the background art and maintaining the consistency of the material usage, the outer diameter L1 of the cross-section is preferably designed to be 200 mm. The 200 mm here is only a preferred value, and it can be flexibly adjusted according to specific requirements in actual applications to adapt to different engineering conditions and design requirements.

[0045] Embodiment 2

[0046] On the basis of Embodiment 1, this embodiment further optimizes the stiffening ring with an I-shaped cross-section structure.

[0047] As Figure 6 shown, the number of the middle annular bodies 22 is one. The middle annular body 22 is connected to the middle part between the inner annular body 21 and the outer annular body 23, and the stiffening ring has an I-shaped cross-section. An inner convex part facing the inner annular body 21 is provided in the middle of the inner side of the outer annular body 23, and an outer convex part facing the outer annular body 23 is provided in the middle of the outer side of the inner annular body 21. The middle annular body 22 is located between the inner annular body 21 and the outer annular body 23. Moreover, an arc transition is adopted between the middle annular body 22 and the inner annular body 21. Similarly, an arc transition is also adopted between the middle annular body 22 and the outer annular body 23.

[0048] In this embodiment, as Figure 6 shown, on the premise of keeping the cross-sectional area equivalent to the rectangular cross-sectional area in the background art and the material usage also being equivalent, by selecting the preferred values mentioned in Embodiment 1, that is: the outer diameter L1 of the cross-section of the arc-shaped annular body is 200 mm, the thickness of the inner annular body 21 is designed to be 66 mm, the thickness of the middle annular body 22 is designed to be 12 mm, and the thickness of the outer annular body 23 is designed to be 102 mm, it can be calculated that Figure 6 the cross-sectional area of the I-shaped cross-section is 6.116×10 -3 m 2 , the moment of inertia is 3.5179143×10 -5 m 4 , and the flexural modulus is 2.88124×10 -4 m 4。In this embodiment, the I-shaped cross-section adopted has an equivalent cross-sectional area and material usage compared with the rectangular cross-section in the background art, but the flexural modulus is not lower than that of the rectangular cross-section in the background art. This result indicates that through the optimization of the cross-sectional shape, the flexural performance not lower than or even slightly better than that of the rectangular cross-section in the background art is achieved. More importantly, the reduction of the overall outer diameter of the cross-section is more adaptable to the pipe joint welding and installation operations of the penstock in the narrow space of the tunnel. For the construction of long tunnels, it helps to reduce the civil engineering excavation cost and also avoids the material consumption caused by simply reducing the outer diameter of the rectangular cross-section in the background art and increasing its cross-sectional thickness.

[0049] Embodiment 3

[0050] On the basis of Embodiment 2, the stiffening ring of the I-shaped cross-section structure is deformed in this embodiment.

[0051] As Figure 7 shown, the number of the middle ring bodies 22 is still one, but the cross-section of the middle ring body 22 is frustum-shaped. Specifically, along the direction from the outer ring body 23 to the inner ring body 21, the thickness of the middle ring body 22 increases in sequence. Moreover, an arc transition is adopted between the middle ring body 22 and the inner ring body 21. Similarly, an arc transition is also adopted between the middle ring body 22 and the outer ring body 23.

[0052] In this embodiment, as Figure 7 shown, on the premise of keeping the cross-sectional area equivalent to that of the rectangular cross-section in the background art and the material usage also being equivalent, by selecting the preferred values mentioned in Embodiment 1, that is: the outer diameter L1 of the cross-section of the arc-shaped ring body is 200 mm, the thickness of the inner ring body 21 is designed to be 80 mm, the thickness of the outer ring body 23 is designed to be 95 mm, the thickness of the upper end of the middle ring body 22 is designed to be 10.33 mm, the thickness of the lower end of the middle ring body 22 is designed to be 18.89 mm, the height of the outer ring body 23 is designed to be 20 mm (the height refers to the height of the outer ring body 23 from top to bottom in the direction shown by Figure 7 ), the height of the inner ring body is designed to be 24 mm (the height refers to the height of the inner ring body 21 from top to bottom in the direction shown by Figure 7 ), the cross-sectional area of the deformed I-shaped cross-section in this embodiment can be calculated to be 6.119×10 -3 m 2 , the moment of inertia is 3.50731×10 -5 m 4 , and the flexural modulus is 3.55268×10 -4 m 4, compared with the rectangular cross-section in the background art, the deformed I-shaped cross-section adopted in this embodiment not only significantly reduces the outer diameter of the cross-section, but more notably, the flexural modulus increases significantly. Compared with the I-shaped cross-section in Embodiment 1, the deformed I-shaped cross-section adopted in this embodiment also significantly increases the flexural modulus on the premise of maintaining the same cross-sectional area, material usage, and outer diameter of the cross-section.

[0053] Obviously, if the flexural modulus of the deformed I-shaped cross-section in this embodiment is designed to be the same as that in the background art, the outer diameter of the cross-section in this embodiment can be further reduced. This design of the deformed I-shaped cross-section not only further optimizes the occupation of the welding operation space in the tunnel, improves the construction efficiency, but also saves the production material cost of the stiffening ring.

[0054] Embodiment 4

[0055] Based on Embodiment 1, this embodiment optimizes the cross-sectional structure including two intermediate ring bodies 22.

[0056] As Figure 8 shown, the number of the intermediate ring bodies 22 is two. The intermediate ring bodies 22 are connected between the inner ring body 21 and the outer ring body 23, making the stiffening ring have a cross-section in the shape of a square. Further, these two intermediate ring bodies 22 can also be appropriately close to the middle parts of the inner ring body 21 and the outer ring body 23, but overall, the stiffening ring still maintains a cross-sectional structure in the shape of a square. Moreover, an arc transition is adopted between the intermediate ring body 22 and the inner ring body 21. Similarly, an arc transition is also adopted between the intermediate ring body 22 and the outer ring body 23.

[0057] In this embodiment, as Figure 8 shown, on the premise of maintaining the same cross-sectional area as that in the background art and the same material usage as that of the rectangular cross-section in the background art, by selecting the preferred values mentioned in Embodiment 1, that is, the outer diameter L1 of the cross-section of the arc-shaped ring body is 200 mm, and the thicknesses of both the inner ring body 21 and the outer ring body 23 are designed to be 100 mm, the thicknesses of both the two intermediate ring bodies 22 are designed to be 8 mm, the height of the inner ring body 21 is designed to be 18 mm (the height refers to the height of the inner ring body 21 from top to bottom in the direction shown in Figure 8 ), the height of the outer ring body 23 is designed to be 18 mm (the height refers to the height of the outer ring body 23 from top to bottom in the direction shown in Figure 8 ), the cross-sectional area of the square cross-section in this embodiment can be calculated to be 6.16×10 -3 m 2 , the moment of inertia is 3.579006×10 -5 m 4 , and the flexural modulus is 3.579006×10 -4m 4 。

[0058] In this embodiment, the adopted I-shaped cross-section achieves the same technical effect as that in Embodiment 3 compared with the rectangular cross-section in the background art.

[0059] It should be noted that there is a direct relationship between the flexural modulus (or flexural section modulus) and the moment of inertia. Specifically, the flexural modulus can be calculated through the moment of inertia. In mechanics of materials, the flexural modulus is usually represented by the letter W, and the moment of inertia is represented by I. For a given cross-section, the relationship between the flexural modulus W and the moment of inertia I can be expressed by the formula W = I / Ymax, where Ymax is the maximum distance from each point of the cross-section to the central axis. This formula shows that the flexural modulus is a function of the moment of inertia divided by the maximum distance, reflecting the relationship between the ability of the cross-section to resist bending and the geometric shape and size of the cross-section. For those skilled in the art, based on the given shape of the stiffening ring and the cross-sectional dimensions, through the calculation and analysis tools built into the mechanical drawing software and in combination with the foregoing formula, the flexural modulus of the cross-section of the stiffening ring can be directly measured. Therefore, the calculation process will not be elaborated here.

[0060] The above is only the specific implementation manner of the present utility model. Any feature disclosed in this specification, unless specifically described, can be replaced by other equivalent or similar-purpose alternative features; all the features disclosed, or all the steps in any method or process, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A stiffening ring for a pressure steel pipe in a tunnel, characterized in that: The invention comprises an arc-shaped ring body, wherein the arc-shaped ring body comprises an inner ring body (21), an intermediate ring body (22) and an outer ring body (23); the thickness of the inner ring body (21) and the outer ring body (23) are both greater than the thickness of the intermediate ring body (22); the intermediate ring body (22) is integrally formed between the inner ring body (21) and the outer ring body (23); the inner ring body (21) has a fitting surface adapted to the outer wall of a pressure steel pipe; inclined welding grooves (5) are symmetrically arranged on both sides of the fitting surface; and the inner ring body can form a welding groove (50) on the pressure steel pipe through the welding grooves (5).

2. A stiffening ring for an in-hole pressure steel pipe according to claim 1, characterized in that: The thickness of the outer ring body (23) is greater than or equal to the thickness of the inner ring body (21).

3. A stiffening ring for an in-hole pressure steel pipe according to claim 2, characterized in that: The number of the intermediate ring body (22) is at least one. When the number of the intermediate ring body (22) is one, the intermediate ring body (22) is connected to the middle portion between the inner ring body (21) and the outer ring body (23) so that the stiffening ring has an I-shaped cross section. When the number of the intermediate ring bodies (22) is two, the intermediate ring body (22) is connected between the inner ring body (21) and the outer ring body (23) so that the stiffening ring has an I-shaped cross section. There is an arc transition between the intermediate ring body (22) and the inner ring body (21), and there is an arc transition between the intermediate ring body (22) and the outer ring body (23).

4. A stiffening ring for an in-hole pressure steel pipe according to claim 3, characterized in that: The cross section of the intermediate ring body (22) is rectangular; an inner protrusion facing the inner ring body (21) is provided at the middle of the inner side of the outer ring body (23); an outer protrusion facing the outer ring body (23) is provided at the middle of the outer side of the inner ring body (21); and the intermediate ring body (22) is located between the inner ring body (21) and the outer ring body (23).

5. A stiffening ring for an in-hole pressure steel pipe according to claim 3, characterized in that: The cross section of the intermediate ring body (22) is in the shape of a truncated cone, and the thickness of the intermediate ring body (22) increases gradually from the outer ring body (23) to the inner ring body (21).

6. A stiffening ring for an in-hole pressure steel pipe according to claim 5, characterized in that: The extended surface of the welding groove (5) and the fitting surface of the inner ring body (21) has an included angle of 45°-55°.

7. A stiffening ring for an in-hole pressure steel pipe according to any one of claims 1 to 6, characterized in that: The outer diameter of the cross section of the arc-shaped ring body is 200 mm.

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