Fire and explosion prevention structure for subsea tunnel pipe joint

Abstract

The application discloses a fire and explosion prevention structure for a pipe joint of a submarine tunnel, and solves the technical problem of unsatisfactory fire and explosion prevention performance of the prior art.The application comprises a first fire and explosion prevention mechanism, a second fire and explosion prevention mechanism, a first rubber waterstop and a second rubber waterstop.The first fire and explosion prevention mechanism comprises a first annular fire and explosion prevention plate A and a first annular fire and explosion prevention plate B, and the first annular fire and explosion prevention plate A and the first annular fire and explosion prevention plate B are distributed at intervals.The second fire and explosion prevention mechanism comprises a second annular fire and explosion prevention plate, and a gap is left between the second annular fire and explosion prevention plate and an inner wall of the pipe joint.The application has a simple structure and a scientific and reasonable design, and the first fire and explosion prevention mechanism and the second fire and explosion prevention mechanism are arranged on the inner wall of the pipe joint connection of the submarine tunnel, so that the submarine tunnel explosion and fire danger can be effectively prevented, and thus the pipe joint sealing structure can be effectively ensured from being affected by the submarine tunnel explosion and / or fire danger, and the safety of the tunnel interior is ensured.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of submarine tunnels, and particularly relates to a fireproof and explosion-proof structure of a submarine tunnel pipe joint. BACKGROUND

[0002] A submarine tunnel is a traffic pipeline built under the seabed of a strait, a gulf or a river mouth to communicate between lands. Compared with a cross-sea bridge, the biggest advantage of a submarine tunnel is that it is built at the bottom of the sea and will not affect navigation and will not be affected by adverse weather at sea.

[0003] There are four main methods for excavating a submarine tunnel, namely, a drill and blast method, a pipe sinking method, a tunneling machine method and a shield method. The pipe sinking method is to sink the prepared pipe joints to the seabed and then connect them to each other. The connection between the two pipe joints needs to be sealed by using a waterproof structure to avoid the infiltration of external seawater into the inside to ensure the safety of the tunnel. Since accidents such as traffic accidents or other human accidents may occur in the submarine tunnel, the fire or explosion caused thereby can be harmful to the tunnel. At present, a fireproof and explosion-proof structure is provided in the tunnel pipe joint, but the fireproof and explosion-proof of the pipe joint connection is relatively weak and cannot resist high temperature or high pressure. Not only will this cause the adjacent pipe joints to displace horizontally or vertically, resulting in the deviation of the tunnel, but also will seriously damage the waterproof structure and cause seawater to flow backward.

[0004] Therefore, the present application provides a fireproof and explosion-proof structure of a submarine tunnel pipe joint to at least solve some of the above problems. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a fireproof and explosion-proof structure of a submarine tunnel pipe joint to at least solve some of the above problems.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] A fireproof and explosion-proof structure of a submarine tunnel pipe joint comprises a first fireproof and explosion-proof mechanism and a second fireproof and explosion-proof mechanism arranged inside the connection between a pipe joint one and a pipe joint two, a first rubber waterstop is arranged on the connection end face of the pipe joint one and the pipe joint two, and a second rubber waterstop is arranged in the connection cavity of the pipe joint one and the pipe joint two.

[0008] The first fireproof and explosion-proof mechanism comprises a first annular fireproof and explosion-proof plate A arranged on the end face of the pipe joint one and a first annular fireproof and explosion-proof plate B arranged on the end face of the pipe joint two, and the first annular fireproof and explosion-proof plate A and the first annular fireproof and explosion-proof plate B are spaced apart.

[0009] The second fireproof and explosion-proof mechanism comprises a second annular fireproof and explosion-proof plate fixed at one end to the inner wall of the pipe joint two, and a gap is left between the second annular fireproof and explosion-proof plate and the inner wall of the pipe joint one.

[0010] Further, the second annular fireproof and explosion-proof plate, the first annular fireproof and explosion-proof plate A, and the first annular fireproof and explosion-proof plate B are filled with aluminum silicate fiber cotton.

[0011] Further, one end surface of the pipe section is provided with a first annular mounting seat, the first annular fireproof and explosion-proof plate A is fixedly connected with the first annular mounting seat; the other end surface of the pipe section is provided with a second annular mounting seat, the first annular fireproof and explosion-proof plate B is fixedly connected with the second annular mounting seat.

[0012] Further, the first annular fireproof and explosion-proof plate A and the first annular fireproof and explosion-proof plate B are both greater than four-thirds of the length of the connecting cavity of the pipe section one and the pipe section two.

[0013] Further, the first annular fireproof and explosion-proof plate A and the first annular fireproof and explosion-proof plate B are both greater than four-thirds of the length of the connecting cavity of the pipe section one and the pipe section two.

[0014] Further, the first annular fireproof and explosion-proof plate A and the first annular fireproof and explosion-proof plate B are both greater than four-thirds of the length of the connecting cavity of the pipe section one and the pipe section two.

[0015] The annular vermiculite fireproof plate is covered with a layer of geomembrane for waterproofing, and the thickness of the geomembrane is 0.5-0.8mm.

[0016] Further, the first annular steel plate is provided with an annular groove on the top surface, the annular vermiculite fireproof plate is embedded in the annular groove, the second annular steel plate is arranged on the annular vermiculite fireproof plate and fastened to the annular vermiculite fireproof plate and the first annular steel plate through bolts, and a sealing ring is arranged at the connection between the second annular steel plate and the annular groove.

[0017] Further, the annular vermiculite fireproof plate includes a plurality of arc-shaped vermiculite fireproof plates spliced together, and the second annular steel plate includes a plurality of arc-shaped steel plates spliced together, and the gaps between adjacent arc-shaped vermiculite fireproof plates and adjacent arc-shaped steel plates are filled with tile glue.

[0018] Further, the other end surface of the pipe section is provided with a third annular mounting seat, the second annular fireproof and explosion-proof plate is fixedly connected with the third annular mounting seat, and the second annular wave plate is arranged between the other end surface of the pipe section and the second annular fireproof and explosion-proof plate, the outer ring of the second annular wave plate is sealingly connected with the other end surface of the pipe section, and the inner ring of the second annular wave plate is sealingly connected with the outer wall of the second annular fireproof and explosion-proof plate.

[0019] Further, the second annular fireproof and explosion-proof plate comprises a third annular steel plate and an annular iron sheet plate sealed and covered on the inner wall of the third annular steel plate, a cavity is arranged between the third annular steel plate and the annular iron sheet plate, a plurality of supporting steel columns are uniformly arranged in the cavity, the two ends of the supporting steel columns are fixed with the third annular steel plate and the annular iron sheet plate respectively, the cavity is filled with inert gas, and the third annular steel plate, the annular iron sheet plate and the supporting steel columns are all made of 304 stainless steel.

[0020] Compared with the prior art, the present application has the following beneficial effects:

[0021] The present application has the advantages of simple structure, scientific and reasonable design, the first fireproof and explosion-proof mechanism and the second fireproof and explosion-proof mechanism arranged on the inner wall of the pipe joint connecting portion of the submarine tunnel can effectively prevent the explosion and fire danger in the submarine tunnel, so that the explosion and / or fire danger in the submarine tunnel can not affect the sealing structure between the pipe joints, and the safety of the tunnel is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a structural section view of the present application.

[0023] Figure 2 It is a section view of the first annular fireproof and explosion-proof plate A or the first annular fireproof and explosion-proof plate B.

[0024] Figure 3 It is a section view of the first annular steel plate.

[0025] Figure 4 It is a section view of the annular vermiculite fireproof plate.

[0026] Figure 5 It is a section view of the second annular steel plate.

[0027] Figure 6 It is a connection diagram of the arc-shaped vermiculite fireproof plate.

[0028] Figure 7 It is a connection diagram of the arc-shaped steel plate.

[0029] Figure 8 It is a section view of the second annular fireproof and explosion-proof plate.

[0030] Among them, the name corresponding to the reference sign is:

[0031] 1 - first pipe joint, 2 - second pipe joint, 4 - first fire and explosion prevention mechanism, 5 - second fire and explosion prevention mechanism, 6 - first rubber waterstop, 7 - second rubber waterstop, 11 - first annular mounting seat, 12 - second annular corrugated plate, 21 - second annular mounting seat, 22 - third annular mounting seat, 41 - first annular fire and explosion prevention plate A, 42 - first annular fire and explosion prevention plate B, 43 - first annular corrugated plate, 44 - first annular steel plate, 45 - annular vermiculite fireproof plate, 46 - second annular steel plate, 47 - geomembrane, 48 - sealing ring, 49 - tile glue, 51 - second annular fire and explosion prevention plate, 52 - third annular steel plate, 53 - annular iron sheet, 54 - cavity, 55 - supporting steel column, 56 - gap, 441 - annular groove, 451 - arc-shaped vermiculite fireproof plate, 461 - arc-shaped steel plate. DETAILED DESCRIPTION

[0032] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0033] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0034] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood in a broad sense, for example, it can be fixed connection, or detachable connection, or integrally connected; of course, it can also be mechanical connection, or electrical connection; in addition, it can also be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. For those of ordinary skill in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0035] As Figures 1-8As shown, the application provides a fire and explosion prevention structure for a pipe joint of a submarine tunnel, which comprises a first fire and explosion prevention mechanism 4 and a second fire and explosion prevention mechanism 5 arranged in the inner part of the joint between a first pipe joint 1 and a second pipe joint 2, a first rubber waterstop 6 arranged on the joint end surface of the first pipe joint 1 and the second pipe joint 2, and a second rubber waterstop 7 arranged in the joint cavity of the first pipe joint 1 and the second pipe joint 2.

[0036] The application has simple structure and scientific and reasonable design, and the first fire and explosion prevention mechanism and the second fire and explosion prevention mechanism arranged on the inner wall of the joint between the pipe joints can effectively prevent the explosion and fire hazards in the submarine tunnel, so that the sealing performance of the first rubber waterstop 6 and the second rubber waterstop 7 between the pipe joints can be effectively ensured, and the external silt or seawater of the submarine tunnel cannot penetrate into the tunnel, thereby ensuring the safety in the tunnel.

[0037] The first rubber waterstop 6 and the second rubber waterstop 7 are both sealed and fixed on the pipe joint end through the mounting seat and the bolt, and the mounting structure of the first rubber waterstop 6 and the second rubber waterstop 7 can refer to the mounting of the conventional sealing band between the pipe joints of the submarine tunnel.

[0038] The first fire and explosion prevention mechanism 4 comprises a first annular fire and explosion prevention plate A41 arranged on the end surface of the first pipe joint 1 and a first annular fire and explosion prevention plate B42 arranged on the end surface of the second pipe joint 2, and the first annular fire and explosion prevention plate A41 and the first annular fire and explosion prevention plate B42 are spaced apart. The length of the first annular fire and explosion prevention plate A41 and the first annular fire and explosion prevention plate B42 is greater than three fourths of the length of the joint cavity of the first pipe joint 1 and the second pipe joint 2. The end surface of the first pipe joint 1 is provided with a first annular mounting seat 11, and the first annular fire and explosion prevention plate A41 is fixedly connected with the first annular mounting seat 11. The end surface of the second pipe joint 2 is provided with a second annular mounting seat 21, and the first annular fire and explosion prevention plate B42 is fixedly connected with the second annular mounting seat 21.

[0039] The first annular fire and explosion prevention plate A41 and the first annular fire and explosion prevention plate B42 are spaced apart in the joint cavity of the pipe joint, and when the fire or explosion occurs in the submarine tunnel, the first rubber waterstop 6 and the second rubber waterstop 7 between the pipe joints can be double-protected, so that the first rubber waterstop 6 and the second rubber waterstop 7 are prevented from being affected by the internal hazards of the submarine tunnel, and the secondary hazard of seawater backflow caused by the internal hazards of the submarine tunnel is prevented. The first annular fire and explosion prevention plate A41 and the first annular fire and explosion prevention plate B42 are spaced apart, and when the pipe joints are impacted to produce relative displacement, the rigid contact between the first annular fire and explosion prevention plate A41 and the first annular fire and explosion prevention plate B42 can be effectively avoided, and the mutual collision and damage of the two when the pipe joints produce relative displacement can be avoided.

[0040] A plurality of first annular corrugated plates 43 are arranged between the first annular fireproof and explosion-proof plate A41 and the first annular fireproof and explosion-proof plate B42, the outer ring of the first annular corrugated plate 43 is sealingly connected with the inner wall of the first annular fireproof and explosion-proof plate A41, and the inner ring of the first annular corrugated plate 43 is sealingly connected with the outer wall of the first annular fireproof and explosion-proof plate B42. The number of the first annular corrugated plate 43 is preferably two, and one is arranged at the end of the first annular fireproof and explosion-proof plate A41 and the first annular fireproof and explosion-proof plate B42, which can effectively improve the sealing performance.

[0041] The first annular fireproof and explosion-proof plate A41 and the first annular fireproof and explosion-proof plate B42 are the same in structure, and each include a first annular steel plate 44, an annular vermiculite fireproof plate 45 arranged on the first annular steel plate 44, and a second annular steel plate 46 arranged on the annular vermiculite fireproof plate 45. The first annular steel plate 44 and the second annular steel plate 46 are each made of 304 stainless steel. The annular vermiculite fireproof plate 45 is wrapped with a layer of geomembrane 47 for waterproofing, and the thickness of the geomembrane 47 is 0.5-0.8mm.

[0042] The first annular steel plate 44 is provided with an annular groove 441 on the top surface, which is matched with the annular vermiculite fireproof plate 45. The annular vermiculite fireproof plate 45 is embedded in the annular groove 441. The second annular steel plate 46 is arranged on the annular vermiculite fireproof plate 45 and is fastened and connected with the second annular steel plate 46, the annular vermiculite fireproof plate 45 and the first annular steel plate 44 through bolts. A sealing ring 48 is arranged at the connection between the second annular steel plate 46 and the annular groove 441.

[0043] The annular vermiculite fireproof plate 45 includes a plurality of arc-shaped vermiculite fireproof plates 451 which are spliced together at the head and tail. The second annular steel plate 46 includes a plurality of arc-shaped steel plates 461 which are spliced together at the head and tail. Tile adhesive 49 is filled in the gaps between adjacent arc-shaped vermiculite fireproof plates 451 and adjacent arc-shaped steel plates 461. The thickness of the arc-shaped vermiculite fireproof plate 451 is 25mm.

[0044] The first annular fireproof and explosion-proof plate A41 and the first annular fireproof and explosion-proof plate B42 are the same in structure, and each include a first annular steel plate 44, an annular vermiculite fireproof plate 45 and a second annular steel plate 46. The first annular steel plate 44 is annular as a whole and is installed at the end of the pipe section through an annular mounting seat. An annular groove 441 is arranged on the outer side of the first annular steel plate 44. The arc-shaped vermiculite fireproof plates 451 are embedded in the annular groove 441 one by one, and are sealed and connected through the arc-shaped steel plates 461 and then fastened through bolts. In this way, the second annular steel plate 46 and the first annular steel plate 44 seal and package the annular vermiculite fireproof plate 45 in the sealed chamber formed by them, and the annular vermiculite fireproof plate 45 is in a sealed environment, which can effectively prevent it from being affected by moisture and affecting the fireproof performance. This design not only has strong fireproof and explosion-proof performance, but also facilitates the later maintenance and replacement of the arc-shaped vermiculite fireproof plates 451.

[0045] The second fireproof and explosion-proof mechanism 5 comprises a second annular fireproof and explosion-proof plate 51 fixed at one end to the inner wall of the pipe section two 2, and a gap 56 is left between the second annular fireproof and explosion-proof plate 51 and the inner wall of the pipe section one 1.

[0046] The pipe section two 2 is provided with a third annular mounting seat 22 at the end face, the second annular fireproof and explosion-proof plate 51 is fixedly connected with the third annular mounting seat 22, and the second annular corrugated plate 12 is arranged between the end face of the pipe section one 1 and the second annular fireproof and explosion-proof plate 51, the outer ring of the second annular corrugated plate 12 is sealingly connected with the end face of the pipe section one 1, and the inner ring of the second annular corrugated plate 12 is sealingly connected with the outer wall of the second annular fireproof and explosion-proof plate 51.

[0047] The gap 56 left between the second annular fireproof and explosion-proof plate 51 and the inner wall of the pipe section one 1 can effectively avoid rigid contact between the second annular fireproof and explosion-proof plate 51 and the inner wall of the pipe section one 1 when the pipe sections are subjected to impact and relative displacement, and avoid mutual collision and damage of the two when relative displacement occurs between the pipe sections.

[0048] The second annular fireproof and explosion-proof plate 51 comprises a third annular steel plate 52 and an annular iron sheet plate 53 sealingly connected to the inner wall of the third annular steel plate 52, a cavity 54 is arranged between the third annular steel plate 52 and the annular iron sheet plate 53, a plurality of support steel columns 55 are uniformly distributed in the cavity 54, the two ends of the support steel columns 55 are fixedly connected with the third annular steel plate 52 and the annular iron sheet plate 53 respectively, the cavity 54 is filled with inert gas, and the third annular steel plate 52, the annular iron sheet plate 53 and the support steel columns 55 are all made of 304 stainless steel.

[0049] The annular iron sheet plate 53 is arranged on the inner wall of the third annular steel plate 52 facing the tunnel, a sealed cavity 54 is formed between the annular iron sheet plate 53 and the inner wall of the third annular steel plate 52, the cavity 54 is filled with inert gas, and when a strong shock wave is generated in the tunnel due to explosion, the sealing structure of the cavity 54 can be damaged, so that the inert gas in the cavity 54 is released, and a secondary fire hazard caused by explosion is prevented.

[0050] The second annular fireproof and explosion-proof plate 51, the first annular fireproof and explosion-proof plate A41 and the first annular fireproof and explosion-proof plate B42 are filled with aluminum silicate fiber cotton. That is, the first annular fireproof and explosion-proof plate A41 and the first annular fireproof and explosion-proof plate B42, the first annular fireproof and explosion-proof plate A41 and the second annular fireproof and explosion-proof plate 51, and the first annular fireproof and explosion-proof plate B42 and the second annular fireproof and explosion-proof plate 51 are uniformly filled with aluminum silicate fiber cotton. By filling the aluminum silicate fiber cotton in the gap between the second annular fireproof and explosion-proof plate 51, the first annular fireproof and explosion-proof plate A41 and the first annular fireproof and explosion-proof plate B42, the aluminum silicate fiber cotton has low thermal conductivity, low heat capacity, excellent chemical stability, excellent thermal stability, and shock resistance, excellent tensile strength, excellent sound absorption, which can effectively improve the fireproof and explosion-proof performance of the subsea tunnel pipe joint fireproof and explosion-proof structure.

[0051] Finally, it should be noted that: the above embodiments are only the preferred embodiments of the present application to illustrate the technical solutions of the present application, but not limit it, of course, nor limit the patent scope of the present application; although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application; that is, any modification or polishing without substantial significance in the main design idea and spirit of the present application, and the technical problems solved are still consistent with the present application, which should be included in the protection scope of the present application; in addition, the technical solutions of the present application are directly or indirectly applied to other related technical fields, which are also included in the patent protection scope of the present application.

Claims

1. A fireproof and explosion-proof structure for a submarine tunnel joint, characterized in that, The first fireproof and explosion-proof mechanism (4) and the second fireproof and explosion-proof mechanism (5) are arranged inside the connection between the pipe section one (1) and the pipe section two (2), the connecting end face of the pipe section one (1) and the pipe section two (2) is provided with the first rubber waterstop (6), and the connecting cavity of the pipe section one (1) and the pipe section two (2) is provided with the second rubber waterstop (7); The first fireproof and explosion-proof mechanism (4) comprises the first annular fireproof and explosion-proof plate A (41) arranged on the end face of the pipe section one (1) and the first annular fireproof and explosion-proof plate B (42) arranged on the end face of the pipe section two (2), and the first annular fireproof and explosion-proof plate A (41) and the first annular fireproof and explosion-proof plate B (42) are distributed at intervals; The second fireproof and explosion-proof mechanism (5) comprises the second annular fireproof and explosion-proof plate (51) fixed to the inner wall of the pipe section two (2) at one end, and a gap (56) is left between the second annular fireproof and explosion-proof plate (51) and the inner wall of the pipe section one (1); The second annular fireproof and explosion-proof plate (51), the first annular fireproof and explosion-proof plate A (41) and the first annular fireproof and explosion-proof plate B (42) are filled with aluminum silicate fiber cotton; The first annular fireproof and explosion-proof plate A (41) and the first annular fireproof and explosion-proof plate B (42) are provided with a plurality of first annular corrugated plates (43), the outer ring of the first annular corrugated plate (43) is sealingly connected to the inner wall of the first annular fireproof and explosion-proof plate A (41), and the inner ring of the first annular corrugated plate (43) is sealingly connected to the outer wall of the first annular fireproof and explosion-proof plate B (42); The first annular fireproof and explosion-proof plate A (41) and the first annular fireproof and explosion-proof plate B (42) are the same in structure and each comprises a first annular steel plate (44), an annular vermiculite fireproof plate (45) arranged on the first annular steel plate (44) and a second annular steel plate (46) arranged on the annular vermiculite fireproof plate (45), and the first annular steel plate (44) and the second annular steel plate (46) are each made of 304 stainless steel; The annular vermiculite fireproof plate (45) is covered with a layer of geomembrane (47) for waterproofing, and the thickness of the geomembrane (47) is 0.5-0.8mm; The end face of the pipe section two (2) is provided with a third annular mounting seat (22), the second annular fireproof and explosion-proof plate (51) is fixedly connected to the third annular mounting seat (22), and the second annular corrugated plate (12) is arranged between the end face of the pipe section one (1) and the second annular fireproof and explosion-proof plate (51), the outer ring of the second annular corrugated plate (12) is sealingly connected to the end face of the pipe section one (1), and the inner ring of the second annular corrugated plate (12) is sealingly connected to the outer wall of the second annular fireproof and explosion-proof plate (51).

2. The fire and explosion proof structure of a pipe joint of a subsea tunnel according to claim 1, characterized in that: The end face of the pipe section one (1) is provided with the first annular mounting seat (11), the first annular fireproof and explosion-proof plate A (41) is fixedly connected to the first annular mounting seat (11), the end face of the pipe section two (2) is provided with the second annular mounting seat (21), and the first annular fireproof and explosion-proof plate B (42) is fixedly connected to the second annular mounting seat (21).

3. The fire and explosion proof structure of a pipe joint of a subsea tunnel according to claim 1, characterized in that: The length of the first annular fireproof and explosion-proof plate A (41) and the first annular fireproof and explosion-proof plate B (42) is greater than four-thirds of the length of the connecting cavity of the pipe section one (1) and the pipe section two (2).

4. The fire and explosion proof structure of a pipe joint of a subsea tunnel according to claim 1, wherein: The first annular steel plate (44) is provided with an annular groove (441) on the top surface, which is matched with the annular vermiculite fireproof plate (45). The annular vermiculite fireproof plate (45) is embedded in the annular groove (441). The second annular steel plate (46) is arranged on the annular vermiculite fireproof plate (45) and is fastened and connected with the second annular steel plate (46) and the annular vermiculite fireproof plate (45) through bolts. The second annular steel plate (46) is provided with a sealing ring (48) at the connection with the annular groove (441).

5. The fire and explosion proof structure of a pipe joint of a subsea tunnel according to claim 4, characterized in that: The annular vermiculite fireproof plate (45) comprises a plurality of arc-shaped vermiculite fireproof plates (451) which are spliced together. The second annular steel plate (46) comprises a plurality of arc-shaped steel plates (461) which are spliced together. The gaps between the adjacent arc-shaped vermiculite fireproof plates (451) and the adjacent arc-shaped steel plates (461) are filled with tile glue (49).

6. The fire and explosion proof structure of a pipe joint of a subsea tunnel according to claim 1, wherein: The second annular fireproof and explosion-proof plate (51) comprises a third annular steel plate (52) and an annular iron sheet plate (53) which is sealed and connected to the inner wall of the third annular steel plate (52). A cavity (54) is arranged between the third annular steel plate (52) and the annular iron sheet plate (53). A plurality of supporting steel columns (55) are uniformly arranged in the cavity (54). The two ends of the supporting steel columns (55) are fixed with the third annular steel plate (52) and the annular iron sheet plate (53) respectively. The cavity (54) is filled with inert gas. The third annular steel plate (52), the annular iron sheet plate (53) and the supporting steel columns (55) are all made of 304 stainless steel.

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