Reusable Temporary Portal Structure and Construction Method for Parallel Jacked Pipe Tunnels

Abstract

The present invention provides a reusable temporary portal structure for parallel pipe-jacking tunnels. It is assembled in a prefabricated manner, with the inner steel section and the outer steel section fixed on the end wall structure. An airbag is arranged in the space enclosed by the inner steel section, the outer steel section and the end wall structure. An inner airbag is arranged between the inner steel section and the retaining structure, and a mounting position is provided for the curtain rubber plate assembly. It can ensure the timely establishment of chamber pressure during pipe-jacking construction, ensure the pressure of the drag reduction slurry injected behind the pipe wall and the pressure of the later replacement cement slurry, and ensure the safety of the entire pipe-jacking construction process. The construction method of the temporary portal structure installs one or two sets of temporary portal structures according to the situation of the pipe-jacking tunnel to be constructed. The temporary portal structure is reused for multiple parallel pipe-jacking tunnels, does not occupy a large area, and the prefabricated construction plan is relatively fast. It can be closely attached to the irregular retaining structure to achieve a sealed effect, ensuring no water leakage and ensuring the safety of the ground and pipelines.

Description

Technical Field

[0001] The present invention belongs to the technical field of pipe jacking tunnel construction, and particularly relates to a reusable temporary portal structure for parallel pipe jacking tunnels and a construction method thereof. Background Art

[0002] With the development of urban construction, trenchless construction methods such as shield tunneling and pipe jacking have received increasing attention. This construction method can not only reduce the impact on surface traffic but also avoid relocating underground pipelines, thus reducing the impact on the lives of citizens. Currently, the net width of a single pipe jacking tunnel no longer meets the usage function requirements. Large-diameter pipe jacking can solve this problem, but the project investment is relatively large. To reduce project costs and meet the requirement of the usable net width, parallel pipe jacking has been successfully implemented in China. The net distance between parallel pipe jackings in Shenzhen is 2.15 m, in Foshan is 0.5 m, and in Nanning is 0.3 m. Since the net distance between pipe jackings is too small, the size of the portal structure in the middle of the pipe jacking is relatively small, making it difficult to meet the structural stress requirements and difficult to construct. After construction, there are many vertical cold joints at the cast-in-place portal ring, and these cold joints are often the leakage channels of the structure, making subsequent leak stoppage difficult to construct, which to a certain extent affects the structural safety and the normal passage of passengers.

[0003] On the other hand, since the portal structure is constructed synchronously with the side wall, there are uneven gaps between the portal structure and the retaining structure. When the pipe jacking starts, the chamber pressure cannot be established in time, resulting in groundwater flowing out from the face, causing accidents such as ground settlement and pipeline rupture. When the pipe jacking is received, due to the gaps at the receiving portal, cotton quilts and other materials are generally used on-site to block the gaps between the cast-in-place portal and the retaining structure. This method is difficult to achieve a blocking effect, resulting in the loss of the resistance-reducing slurry behind the pipe jacking. The replacement cement slurry after the pipe jacking tunnel is also discharged from this gap, and the pipe joints cannot be stabilized in time. Groundwater continuously flows out from this gap, causing problems such as ground settlement and even collapse.

[0004] In the prior art, when jacking the second tunnel, the assembled portal structure needs to be demolished and rotated before reinstalling devices such as the curtain cloth. Moreover, this technology is limited by the structural size and needs to be customized according to different pipe jackings, with little reusability. To solve the gap problem between the portal and the retaining structure, there is a certain risk in pipe jacking construction. In addition, the prior art cannot minimize the tunnel spacing as much as possible, resulting in too large a tunnel spacing and inconvenience in utilization. Summary of the Invention

[0005] In view of the technical problems existing in the prior art, the present invention provides a reusable temporary portal structure and construction method for parallel pipe-jacking tunnels. The temporary portal structure is assembled in a modular manner, and each component can be directly transported to the site for installation, with less requirements for traffic conditions and site, light weight, and no need for large-scale hoisting equipment. It is more convenient and easy to use compared with the current cast-in-place concrete method. Moreover, the entire temporary portal structure has a simple form, is easy to manufacture, and can be recycled. This construction method does not occupy a large area, and the modular construction plan is relatively fast. It can be closely attached to the irregular retaining structure to achieve a sealed effect, ensuring no water leakage and the safety of the ground and pipelines.

[0006] The technical solution adopted by the present invention is: a reusable temporary portal structure for parallel pipe-jacking tunnels, including: inner steel profiles, fixed steel plates, steel profile joint plates, rubber waterproof sheets, water-swelling waterstop rubber, inner airbags, waterstop rubber, outer steel profiles, web bolts, external steel plates, steel wires, airbags, fixing parts and movable parts. One ends of two inner steel profiles are connected through a steel profile joint plate, and the other ends are both fixed with fixed steel plates. The fixed steel plates are fixed to the end wall structure through chemical anchor bolts. A rubber waterproof sheet is arranged between the fixed steel plates and the end wall structure. An inner airbag is arranged between the inner steel profile and the retaining structure. Water-swelling waterstop rubber is arranged between the inner airbag and the inner steel profile. Waterstop rubber is arranged between the inner airbag and the retaining structure. One ends of two outer steel profiles are connected through a steel profile joint plate, and the other ends are both fixed with fixed steel plates. The fixed steel plates are fixed to the end wall structure through chemical anchor bolts. A rubber waterproof sheet is arranged between the fixed steel plates and the end wall structure. Holes are formed on two flanges on the opposite sides of the inner steel profile and the outer steel profile, and they are connected through steel wires. Multiple airbags are arranged in the space surrounded by the inner steel profile, the outer steel profile, the steel wire and the end wall structure. Water-swelling waterstop rubber is arranged between the airbags. Water-swelling waterstop rubber is arranged between the airbag and the inner steel profile and between the airbag and the outer steel profile. A rubber waterproof sheet is arranged between the airbag and the end wall structure. An arc-shaped structure is arranged beside the connection part of the end wall structure and the outer steel profile. The arc-shaped structure includes multiple movable parts and two L-shaped fixing parts. One sides of the two fixing parts are respectively connected to the end wall structure and the outer steel profile, and the other sides are connected through a plurality of sequentially connected movable parts. Web bolts are fixed on the web of the outer steel profile. The external steel plate is fixed to the web bolts and the outer steel profile. The web bolts are connected to the curtain rubber plate assembly.

[0007] Further, round holes and strip holes are formed on the steel profile joint plate. The round holes are connected to the inner steel profile or the outer steel profile through bolts, and the strip holes are welded to the bolts through plug welding and connected to the inner steel profile or the outer steel profile.

[0008] Further, the web of the inner steel profile is provided with holes.

[0009] Furthermore, web bolts are provided on the end wall structure.

[0010] The technical solution adopted by the present invention is also: a construction method for a reusable temporary portal structure of a parallel pipe jacking tunnel, including the following steps:

[0011] S1: According to the situation of the first pipe jacking tunnel to be constructed, install one or two sets of temporary portal structures;

[0012] S2: Install web bolts on the end wall structure, and install a curtain rubber plate assembly at the first pipe jacking tunnel;

[0013] S3: The first pipe jacking tunnel completes tunneling start or reception; remove the curtain rubber plate assembly;

[0014] S4: According to the situation of the second pipe jacking tunnel to be constructed, remove the temporary portal structure or its arc structure of the first pipe jacking tunnel, and install it on the second pipe jacking tunnel;

[0015] S5: Install web bolts on the end wall structure, and install a curtain rubber plate assembly at the second pipe jacking tunnel;

[0016] S6: The second pipe jacking tunnel completes tunneling start or reception; remove the curtain rubber plate assembly;

[0017] S7: When the number of pipe jacking tunnels is two, perform step S8; when the number of pipe jacking tunnels is more than two, repeat steps S4 - S6 until the tunneling start or reception of all pipe jacking tunnels is completed;

[0018] S8: Remove all components of the temporary portal structure;

[0019] S9: Construct a post - cast concrete portal ring.

[0020] Furthermore, the construction steps of the temporary portal structure include:

[0021] S1 - 1: After the construction of the end wall structure at the pipe jacking start and reception ends, lay out according to the drawings, drill holes, and construct chemical anchor bolts;

[0022] S1 - 2: Apply two coats of water - swelling water - stop glue at the intersection of the retaining structure and the inner airbag;

[0023] S1 - 3: Place a rubber waterproof board, install the inner section steel at the lower part, and connect it to the end wall structure through a fixing steel plate using chemical anchor bolts;

[0024] S1 - 4: Install the inner section steel at the upper part, and connect it to the end wall structure through a fixing steel plate using chemical anchor bolts;

[0025] S1 - 5: Apply water - swelling water - stop glue on the two inner section steels;

[0026] S1-6: Install the inner airbag;

[0027] S1-7: Use steel joint plates to fix the two inner steel sections;

[0028] S1-8: repeat step S1-1;

[0029] S1-9: Install the outer steel section at the bottom and connect it to the end wall structure through the fixed steel plate with chemical anchor bolts; the outer steel section is pre-installed with web bolts and external steel plates;

[0030] S1-10: Install the outer steel section located at the upper part and connect it to the end wall structure through the fixed steel plate with chemical anchor bolts;

[0031] S1-11: Apply water-swellable waterproofing glue to the outer steel section;

[0032] S1-12: Use steel wire ropes to cross-connect the inner and outer steel sections;

[0033] S1-13: Place airbags between the inner steel section, outer steel section and steel wire rope, and apply water-expandable waterproof glue to the airbags;

[0034] S1-14: Use steel joint plates to fix the two outer steel sections;

[0035] S1-15: Connect the fixings to the end wall structure by drilling holes and using chemical anchor bolts;

[0036] S1-16: Use bolts to connect another fixing to the outer steel section;

[0037] S1-17: The two fixed parts are connected to the movable part by bolts.

[0038] The tunnel door structure of the present invention can be applied to jacking structures of different sizes, meeting the requirements of jacking tunnel and receiving airtightness. When the second, third and fourth jacking tunnels are jacked, there is no need to dismantle the tunnel door structure, and only the curtain cloth needs to be removed and installed on the second tunnel door. After the first and second jacking tunnels are connected, the bottom three or four jacking tunnels can be dismantled and used as the starting receiving tunnel door, which is not affected by the jacking direction of the jacking tunnel.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] 1. The assembled temporary tunnel door structure proposed by the present invention is quick to install and easy to use, and can be applied to pipe jacking tunnels of different sizes.

[0041] 2. The present invention improves the problem of airtightness at the time of the initial reception of the traditional parallel tunnel jacking pipe, and can ensure that the warehouse pressure is established in time during the jacking pipe construction, ensure the pressure of the drag reduction mud injected behind the jacking pipe wall and the pressure of the cement slurry replaced later, and ensure the safety of the entire jacking pipe construction process.

[0042] 3. The entire temporary portal structure adopted in the present invention is assembled in a prefabricated manner, with a simple structural form, easy to manufacture, convenient for maintenance, and recyclable, belonging to a green construction method.

[0043] 4. The present invention is a reusable temporary portal structure, which can be completely disassembled after construction and used for other similar projects. The present invention can reduce the number of vertical joints of the post-cast portal ring of the pipe jacking tunnel, reduce the leakage problem during the operation stage, reduce diseases, and further ensure the operation safety, which conforms to the concept of resource conservation. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a cross-sectional schematic view of an embodiment of the present invention;

[0045] Figure 2 It is a front view of the internal steel section of an embodiment of the present invention;

[0046] Figure 3 It is a side view of the internal steel section of an embodiment of the present invention;

[0047] Figure 4 It is a structural schematic view of the steel section joint plate of an embodiment of the present invention;

[0048] Figure 5 It is a front view of the external steel section of an embodiment of the present invention;

[0049] Figure 6 It is a longitudinal sectional schematic view of an embodiment of the present invention;

[0050] Figure 7 It is a schematic diagram of the wire rope installation of an embodiment of the present invention;

[0051] Figure 8 It is a schematic view of the arc structure of an embodiment of the present invention;

[0052] Figure 9 It is a front view of the fixing member of an embodiment of the present invention;

[0053] Figure 10 It is a side view of the fixing member of an embodiment of the present invention;

[0054] Figure 11 It is a top view of the fixing member of an embodiment of the present invention;

[0055] Figure 12 It is a structural schematic view of the movable member of an embodiment of the present invention;

[0056] Figure 13 It is an installation schematic diagram of two parallel pipe jacking tunnels of an embodiment of the present invention Figure 1 ;

[0057] Figure 14 Installation schematic of two parallel pipe - jacking tunnels according to an embodiment of the present invention Figure 2 ;

[0058] Figure 15 Installation schematic of two parallel pipe - jacking tunnels according to an embodiment of the present invention Figure 3 ;

[0059] Figure 16 Installation schematic of three parallel pipe - jacking tunnels according to an embodiment of the present invention Figure 1 ;

[0060] Figure 17 Installation schematic of three parallel pipe - jacking tunnels according to an embodiment of the present invention Figure 2 ;

[0061] Figure 18 Installation schematic of three parallel pipe - jacking tunnels according to an embodiment of the present invention Figure 3 ;

[0062] Figure 19 Installation schematic of three parallel pipe - jacking tunnels according to an embodiment of the present invention Figure 4 。

[0063] In the figure: 1 - inner - side steel section; 2 - fixing steel plate; 3 - steel - section joint plate; 4 - end - wall structure; 5 - chemical anchor bolt; 6 - rubber waterproof sheet; 7 - water - swelling water - stop rubber; 8 - inner - side airbag; 9 - water - stop rubber; 10 - outer - side steel section; 11 - web bolt; 12 - external steel plate; 13 - steel wire rope; 14 - airbag; 15 - fixing part; 16 - movable part; 17 - curtain rubber sheet assembly; 18 - retaining structure. Detailed implementation manners

[0064] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0065] Embodiment 1

[0066] The embodiment of the present invention provides a reusable temporary portal structure for parallel pipe - jacking tunnels, as Figures 1-12 shown, which includes an inner - side steel section 1, a fixing steel plate 2, a steel - section joint plate 3, a rubber waterproof sheet 6, a water - swelling water - stop rubber 7, an inner - side airbag 8, a water - stop rubber 9, an outer - side steel section 10, a web bolt 11, an external steel plate 12, a steel wire rope 13, an airbag 14, a fixing part 15 and a movable part 16.

[0067] One end of two inner steel profiles 1 is connected by a steel profile joint plate 3, and fixed steel plates 2 are welded and fixed to the other ends. Round holes are formed in the fixed steel plates 2 and fixed to the end wall structure 4 through chemical anchor bolts 5. A rubber waterproof plate 6 is arranged between the fixed steel plate 2 located below and the end wall structure 4. Round holes and strip holes are formed in the steel profile joint plate 3. The round hole is connected to one of the inner steel profiles 1 through a bolt, and the strip hole is connected to the other inner steel profile 1 through a plug hole welding bolt. The combination mode of the inner steel profile 1 and the steel profile joint plate 3 enables its vertical height to be adjusted according to the actual height, suitable for portal structures of different heights. The inner steel profile 1 is subjected to lightweight treatment and has holes in the web. An inner airbag 8 is arranged between the inner steel profile 1 and the enclosure structure 18. A water-swellable sealing rubber 7 is arranged between the inner airbag 8 and the web and flange of the inner steel profile 1 respectively. Two sealing rubbers 9 are arranged between the inner airbag 8 and the enclosure structure 18.

[0068] One end of two outer steel profiles 10 is connected by a steel profile joint plate 3, and fixed steel plates 2 are welded and fixed to the other ends. Round holes are formed in the fixed steel plates 2 and fixed to the end wall structure 4 through chemical anchor bolts 5. A rubber waterproof plate 6 is arranged between the fixed steel plate 2 and the end wall structure 4. Round holes and strip holes are formed in the steel profile joint plate 3. The round hole is connected to one of the outer steel profiles 10 through a bolt, and the strip hole is connected to the other outer steel profile 10 through a plug hole welding bolt. Round holes are equidistantly formed in the two flanges on the opposite sides of the inner steel profile 1 and the outer steel profile 10, and steel wires 13 are cross-penetrated into the round holes on the flanges of the inner steel profile 1 and the outer steel profile 10. A plurality of airbags 14 are sequentially placed from bottom to top in the space enclosed by the inner steel profile 1, the outer steel profile 10, the steel wires 13 and the end wall structure 4, which can be suitable for pipe jacking tunnels of different heights. Two water-swellable sealing rubbers 7 are arranged between adjacent airbags 14. A water-swellable sealing rubber 7 is arranged between the airbag 14 and the web and flange of the inner steel profile 1 and the outer steel profile 10 respectively. A rubber waterproof plate 6 is arranged between the airbag 14 and the end wall structure 4.

[0069] An arc structure is arranged beside the connection part of the end wall structure 4 and the outer steel profile 10. The arc structure includes a plurality of movable parts 16 and two L-shaped fixing parts 15. One sides of the two fixing parts 15 are respectively connected to the end wall structure 4 and the outer steel profile 10. The other sides of the two fixing parts 15 are connected through a plurality of movable parts 16 connected in sequence. The fixing part 15 and the movable part 16, and the movable part 16 and the movable part 16 are connected through bolts.

[0070] On one side of the web of the outer steel section 10 facing away from the enclosure structure 18, web bolts 11 are fixed. The external steel plate 12 is fixed to the web bolts 11 and the outer steel section 10. Ordinary bolts are provided on the end wall structure 4. The curtain rubber plate assembly 17 is connected to the web bolts 11 and the ordinary bolts. After the curtain rubber plate assembly 17 is installed, the pipe jacking starts and receives normally; the temporary portal at the middle small clear distance pipe jacking is removed, and the post-cast portal ring is constructed, thereby reducing two vertical construction joints, reducing the leakage at this place, and reducing the impact on the operation.

[0071] Embodiment 2

[0072] An embodiment of the present invention provides a construction method for a reusable temporary portal structure of parallel pipe jacking tunnels. The working condition is two parallel pipe jacking tunnels, including the following steps:

[0073] S1: After the construction of the end wall structure 4 at the pipe jacking starting and receiving ends is completed, install a set of temporary portal structures at the first pipe jacking tunnel.

[0074] S1-1: Loft according to the drawings, drill holes, and construct chemical anchor bolts 5;

[0075] S1-2: Apply two coats of water-swelling waterstop glue 7 at the intersection of the enclosure structure 18 and the inner airbag 8;

[0076] S1-3: Place the rubber waterproof board 6, install the inner steel section 1 at the lower part, and connect it to the end wall structure 4 through the fixing steel plate 2 with chemical anchor bolts 5;

[0077] S1-4: Install the inner steel section 1 at the upper part, and connect it to the end wall structure 4 through the fixing steel plate 2 with chemical anchor bolts 5;

[0078] S1-5: Apply water-swelling waterstop glue 7 on the two inner steel sections 1;

[0079] S1-6: Install the inner airbag 8;

[0080] S1-7: Fix the two inner steel sections 1 with a steel section joint plate 3;

[0081] S1-8: Repeat step S1-1;

[0082] S1-9: Install the outer steel section 10 at the lower part, and connect it to the end wall structure 4 through the fixing steel plate 2 with chemical anchor bolts 5; web bolts 11 and an external steel plate 12 are pre-installed on the outer steel section 10;

[0083] S1-10: Install the outer steel section 10 at the upper part, and connect it to the end wall structure 4 through the fixing steel plate 2 with chemical anchor bolts 5;

[0084] S1-11: Apply water-swelling waterstop glue 7 on the outer steel section 10;

[0085] S1-12: The inner steel section 1 and the outer steel section 10 are cross-connected by a wire rope 13;

[0086] S1-13: An airbag 14 is placed between the inner steel section 1, the outer steel section 10 and the wire rope 13, and a water-swellable water-stop rubber 7 is applied to the airbag 14;

[0087] S1-14: Two outer steel sections 10 are fixed by a steel section joint plate 3;

[0088] S1-15: Through positioning drilling, a chemical anchor bolt 5 is used to connect the fixing member 15 to the end wall structure 4;

[0089] S1-16: And a bolt is used to connect another fixing member 15 to the outer steel section 10;

[0090] S1-17: The two fixing members 15 are connected by bolts to the movable member 16. The connection angle of the movable member is determined according to the clearance between the outer edge of the pipe jacking, and the movable member 16 and the fixing member 15 are connected by bolts 6.

[0091] S2: Ordinary bolts are installed on the end wall structure 4, and a curtain rubber plate assembly 17 is installed at the first pipe jacking tunnel; as Figure 13 shown.

[0092] S3: The first pipe jacking tunnel completes tunneling start or reception; after the tunnel is connected, the connected curtain rubber plate assembly 17 is disassembled.

[0093] S4: The fixing member 15 and the movable member 16 at the arc of the first pipe jacking tunnel are removed, and steps S1-15 to S1-17 are repeated and installed at the corresponding arc position of the second pipe jacking tunnel.

[0094] S5: Web bolts 11 are installed on the end wall structure 4, and a curtain rubber plate assembly 17 is installed at the second pipe jacking tunnel; as Figure 14 shown.

[0095] S6: The second pipe jacking tunnel completes tunneling start or reception; the curtain rubber plate assembly 17 is removed.

[0096] S7: All components of the prefabricated temporary portal structure are removed;

[0097] S8: A cast-in-place concrete portal ring is constructed, as Figure 15 shown.

[0098] Embodiment 3

[0099] An embodiment of the present invention provides a construction method for a reusable temporary portal structure of parallel pipe jacking tunnels. The working condition is three parallel pipe jacking tunnels, including the following steps:

[0100] Step 1: Install the first set of temporary portal structures on the left side of the first pipe-jacking tunnel according to steps S1-1 to S1-17 of Embodiment 2.

[0101] Step 2: Install the second set of temporary portal structures on the right side of the first pipe-jacking tunnel according to steps S1-1 to S1-17 of Embodiment 2.

[0102] Step 3: Install bolts on the end wall structure 4 and install the curtain rubber plate assembly 17 at the first pipe-jacking tunnel; as Figure 16 shown.

[0103] Step 4: The first pipe-jacking tunnel normally starts tunneling or receiving; after the tunnel is connected, disassemble the connected curtain rubber plate assembly 17.

[0104] Step 5: Demolish the first set of temporary portal structures and install them on the right side of the second pipe-jacking tunnel; install the fixing parts 15 and movable parts 16 of the first set of temporary portal structures at the corresponding arc positions on the right side of the second pipe-jacking tunnel. Install the fixing parts 15 and movable parts 16 at the circular arc of the pipe-jacking tunnel, and disassemble and install them during the construction of different pipe-jacking tunnels for repeated use.

[0105] Step 6: Demolish the fixing parts 15 and movable parts 16 of the second set of temporary portal structures and install them at the corresponding arc positions on the left side of the second pipe-jacking tunnel.

[0106] Step 7: Install bolts on the end wall structure 4 and install the curtain rubber plate assembly 17 of the second pipe-jacking tunnel; as Figure 17 shown. The second pipe-jacking tunnel normally starts tunneling or receiving; after the tunnel is connected, disassemble the connected curtain rubber plate assembly 17.

[0107] Step 8: Demolish the second set of temporary portal structures and install them on the right side of the third pipe-jacking tunnel; install the fixing parts 15 and movable parts 16 of the second set of temporary portal structures at the corresponding arc positions on the right side of the third pipe-jacking tunnel.

[0108] Step 9: Demolish the fixing parts 15 and movable parts 16 of the first set of temporary portal structures and install them at the corresponding arc positions on the left side of the third pipe-jacking tunnel.

[0109] Step 10: Install bolts on the end wall structure 4 and install the curtain rubber plate assembly 17 of the third pipe-jacking tunnel; as Figure 18 shown. The third pipe-jacking tunnel normally starts tunneling or receiving.

[0110] Step 11: Demolish all components of the assembled temporary portal structure.

[0111] Step 12: Construct the cast-in-place concrete post-cast portal ring. As Figure 19 shown.

[0112] The present invention has been described in detail through the embodiments above. However, the content described above is only an exemplary embodiment of the present invention and cannot be considered as defining the scope of implementation of the present invention. The protection scope of the present invention is defined by the claims. All those who utilize the technical solutions of the present invention, or those skilled in the art who, inspired by the technical solutions of the present invention, design similar technical solutions within the essence and protection scope of the present invention to achieve the above technical effects, or make equivalent changes and improvements to the scope of the application, etc., should still fall within the scope of patent coverage protection of the present invention.

Claims

1. Reusable temporary portal structure for parallel pipe-jacking tunnels, characterized in that: Including: Inner steel shapes, fixed steel plates, steel shape joint plates, rubber waterproof plates, water-swelling waterstop rubber, inner airbags, waterstop rubber, outer steel shapes, web bolts, external steel plates, steel wires, airbags, fixtures and moving parts. One ends of two inner steel shapes are connected by a steel shape joint plate, and the other ends are both fixed with fixed steel plates. The fixed steel plates are fixed to the end wall structure by chemical anchor bolts. A rubber waterproof plate is arranged between the fixed steel plates and the end wall structure. An inner airbag is arranged between the inner steel shape and the retaining structure. A water-swelling waterstop rubber is arranged between the inner airbag and the inner steel shape. A waterstop rubber is arranged between the inner airbag and the retaining structure. One ends of two outer steel shapes are connected by a steel shape joint plate, and the other ends are both fixed with fixed steel plates. The fixed steel plates are fixed to the end wall structure by chemical anchor bolts. A rubber waterproof plate is arranged between the fixed steel plates and the end wall structure. Holes are formed in two flange edges on the opposite sides of the inner steel shape and the outer steel shape, and they are connected by steel wires. A plurality of airbags are arranged in the space surrounded by the inner steel shape, the outer steel shape, the steel wires and the end wall structure. A water-swelling waterstop rubber is arranged between the airbags. A water-swelling waterstop rubber is arranged between the airbag and the inner steel shape and between the airbag and the outer steel shape. A rubber waterproof plate is arranged between the airbag and the end wall structure. An arc-shaped structure is arranged beside the connection part of the end wall structure and the outer steel shape. The arc-shaped structure includes a plurality of moving parts and two L-shaped fixtures. One sides of the two fixtures are respectively connected to the end wall structure and the outer steel shape, and the other sides are connected by a plurality of sequentially connected moving parts. Web bolts are fixed on the web of the outer steel shape. The external steel plate is fixed to the web bolts and the outer steel shape. The web bolts are connected to the curtain rubber plate assembly; Round holes and strip holes are formed in the steel shape joint plate. The round holes are connected to the inner steel shape or the outer steel shape by bolts. The strip holes are connected to the inner steel shape or the outer steel shape by plug weld bolts; The web of the inner steel shape is provided with holes.

2. The reusable temporary portal structure for parallel pipe-jacking tunnels according to claim 1, wherein: The web bolts are arranged on the end wall structure.

3. A construction method of a reusable temporary portal structure for parallel pipe jacking tunnels according to any one of claims 1-2, comprising the following steps: S1: Install one set or two sets of temporary portal structures according to the situation of the first pipe jacking tunnel to be constructed; S2: Install web bolts on the end wall structure, and install the curtain rubber plate assembly at the first pipe jacking tunnel; S3: The first pipe jacking tunnel completes tunneling start or reception; Remove the curtain rubber plate assembly; S4: According to the situation of the second pipe jacking tunnel to be constructed, remove the temporary portal structure or its arc-shaped structure of the first pipe jacking tunnel and install it on the second pipe jacking tunnel; S5: Install web bolts on the end wall structure, and install the curtain rubber plate assembly at the second pipe jacking tunnel; S6: The second pipe jacking tunnel completes tunneling start or reception; Remove the curtain rubber plate assembly; S7: When the number of pipe jacking tunnels is two, perform step S8; When the number of pipe jacking tunnels is more than two, repeat steps S4-S6 until the tunneling start or reception of all pipe jacking tunnels is completed; S8: Demolish all components of the temporary portal structure; S9: Construct the post-cast concrete portal ring.

4. The construction method of the reusable temporary portal structure for parallel pipe-jacking tunnels according to claim 3, characterized in that: The construction steps of the temporary portal structure include: S1-1: After the construction of the pipe jacking launching and receiving end wall structures, loft the lines according to the drawings, drill holes, and construct chemical anchor bolts; S1-2: Apply two coats of water-swelling waterstop glue at the intersection of the retaining structure and the inner airbag; S1-3: Place the rubber waterproof board, install the inner steel section at the lower part, and connect it to the end wall structure through a fixed steel plate using chemical anchor bolts; S1-4: Install the inner steel section at the upper part, and connect it to the end wall structure through a fixed steel plate using chemical anchor bolts; S1-5: Apply water-swelling waterstop glue on the two inner steel sections; S1-6: Install the inner airbag; S1-7: Fix the two inner steel sections using a steel section joint plate; S1-8: Repeat step S1-1; S1-9: Install the outer steel section at the lower part, and connect it to the end wall structure through a fixed steel plate using chemical anchor bolts; web bolts and external steel plates are pre-installed on the outer steel section; S1-10: Install the outer steel section at the upper part, and connect it to the end wall structure through a fixed steel plate using chemical anchor bolts; S1-11: Apply water-swelling waterstop glue on the outer steel section; S1-12: Cross-connect the inner steel section and the outer steel section using steel wire ropes; S1-13: Place an airbag between the inner steel section, the outer steel section and the steel wire rope, and apply water-swelling waterstop glue on the airbag; S1-14: Fix the two outer steel sections using a steel section joint plate; S1-15: Connect the fixture to the end wall structure through positioning drilling using chemical anchor bolts; S1-16: And connect another fixture to the outer steel section using bolts; S1-17: Connect the two fixtures through bolts to the movable part.

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