A hole structure and a breaking method

Abstract

The present application relates to the technical field of liaison passage construction, in particular to a hole door structure and breaking method, which solves the problems of high construction risk and big safety hidden danger in the prior art. The hole door structure comprises a hole door assembly, and a detachable hole door main reinforcement is arranged in the hole door assembly, and the end of the hole door main reinforcement extends out of the side edge of the hole door assembly. The breaking method of the hole door structure comprises the following steps: connecting the heating device and the power supply device when breaking the hole door, heating and warming the thermoplastic concrete structure by the heating device, softening the thermoplastic concrete structure, and then pulling out the hole door main reinforcement from the pouring hole, and then breaking the hole door assembly by the cutter head of the shield machine. Advantageous effects: the hole door main reinforcement in the hole door assembly can be pulled out when breaking the hole door, the structural strength of the hole door assembly is reduced, the hole door assembly with the hole door main reinforcement pulled out will not cause blockage to the conveying screw of the shield machine after being broken by the shield machine, the normal use of the shield machine is ensured, and the hole door breaking efficiency is ensured.

Description

Technical Field

[0001] This invention relates to the field of construction technology for connecting passages, and in particular to a portal structure and its demolition method. Background Technology

[0002] Mechanical tunneling is a relatively new technology in the construction of connecting tunnels. This method involves using a conical cutterhead to cut tunnel segments within a closed environment, such as a sleeve, and then expelling debris such as fiberglass reinforcement and concrete materials through a screw conveyor to complete the tunnel segment removal. However, the mechanical tunneling process for connecting tunnels often faces the following problems: extremely low efficiency when removing main tunnel segments, with a tunneling speed of less than 1 mm / min, severely impacting construction efficiency; the use of similarly high-performance, cuttable fiberglass reinforcement is difficult to completely cut during the cutterhead advance, leading to slow tunnel segment removal and screw conveyor blockage; even when tunneling in soft rock formations, due to the high strength of the tunnel portal structure, the tunnel boring machine still needs to use a "roller cutter + scraper" cutterhead design, significantly increasing project costs.

[0003] Patent CN 109339819 A discloses a composite segment and its removal method for rapid demolition during the construction of a tunnel connecting passage. The method involves using sulfur concrete and cuttable glass fiber reinforced plastic (GFRP) reinforcement to construct the sulfur concrete lining inside the tunnel portal within the main tunnel. This lining is then integrated with the external steel grating outside the tunnel portal, forming a single composite segment. An electrically conductive heating wire is embedded within the sulfur concrete lining inside the portal. When energized, the heating wire softens the sulfur concrete, making the concrete at the portal location more porous and facilitating its removal. However, the presence of GFRP reinforcement and steel grating at the portal location presents significant challenges during demolition. Furthermore, the GFRP reinforcement can clog the tunnel boring machine's conveyor, affecting its normal operation and reducing the efficiency of portal demolition. Summary of the Invention

[0004] This invention proposes a tunnel portal structure and a method for breaking it, which solves the problem in the prior art that breaking the tunnel portal section can easily block the shield machine's conveyor screw conveyor and affect the normal operation of the shield machine.

[0005] The technical solution of this invention is implemented as follows:

[0006] A portal structure includes a portal assembly with detachable main reinforcement bars. The ends of the main reinforcement bars extend beyond the sides of the portal assembly. The main reinforcement bars are made of steel bars or other structural elements such as steel strands. During portal breaching, the main reinforcement bars can be removed from the portal assembly, reducing the structural strength of the assembly. After the portal assembly with the main reinforcement bars removed is breached by the tunnel boring machine (TBM), it will not clog the TBM's feed screw conveyor, ensuring the normal operation of the TBM and maximizing portal breaching efficiency.

[0007] The portal assembly includes a portal concrete structure with a thermoplastic structure mounted on it. The main reinforcement bars of the portal are fitted into the thermoplastic structure. The portal concrete structure uses the same concrete material as conventional shield tunneling portals. Before the portal is demolished, the thermoplastic structure can be heated to a soft or fluid state, and then the main reinforcement bars can be pulled out, effectively solving the problem of difficult cutting and demolition of the portal structure. After the main reinforcement bars are pulled out, the portal concrete structure can still provide some support for ground stress, ensuring construction safety.

[0008] The thermoplastic structure includes an isolation device installed on the portal concrete structure. The main reinforcement bars of the portal pass through the isolation device, which contains a thermoplastic concrete structure. A heating device is installed within the thermoplastic concrete structure. When the heating device is powered on, it heats the thermoplastic concrete structure, softening it and facilitating the extraction of the main reinforcement bars from the portal structure.

[0009] The portal assembly is also equipped with fixed main reinforcement bars, which are embedded within the concrete structure. This combination of fixed and detachable portal main reinforcement bars forms the steel structural framework of the portal concrete structure. Even when the tunnel boring machine support system fails to provide adequate support, the reinforcement bars can be pulled out to temporarily maintain the stability of the portal structure before tunneling. During the early tunneling and support stages, the portal main reinforcement bars can fulfill their load-bearing function, ensuring the safety and stability of the load-bearing structure within the tunnel even without portal breaching.

[0010] The portal assembly is connected to a matching lining assembly on its side. The lining assembly has injection holes, and the main reinforcement bars of the portal extend out of the lining assembly from these injection holes. The ends of the main reinforcement bars are fitted with fixing structures that cooperate with the lining assembly. The portal assembly and lining assembly are fabricated as a single piece using a casting method. During segment prefabrication, thermoplastic concrete is injected through the injection holes, completely encasing the main reinforcement bars and heating devices within the thermoplastic concrete. The main reinforcement bars are then fixed to the inner wall of the lining assembly using fixing devices.

[0011] The fixing structure includes a threaded structure at the end of the main reinforcement of the tunnel portal, with a nut connected to the threaded structure. After the thermoplastic concrete is poured and cooled to solidify, tightening the nut ensures the anchoring effect between the main reinforcement of the tunnel portal and the concrete structure of the tunnel portal, preventing the tunnel portal assembly from detaching from the lining assembly under its own weight and ground load, and ensuring the relative position stability of the tunnel portal assembly and the lining assembly during the installation and use of the tunnel segments.

[0012] A portal plate is provided between the portal assembly and the lining assembly. The portal plate has reserved holes through which the main reinforcement bars of the portal pass. After the portal assembly is removed, the portal plate can ensure the structural stability of the lining assembly, thereby ensuring the safety of construction; the reserved holes facilitate the installation of the main reinforcement bars of the portal.

[0013] The portal panel is either an arc-shaped panel or a flat panel, and multiple portal panels are spliced ​​together to form a ring structure. The ring structure is circular or rectangular, and provides support for the portal structure, ensuring the stability of the portal structure after the portal components are destroyed.

[0014] The lining assembly includes a lining concrete structure and lining main reinforcement bars embedded within the lining concrete structure. The ends of the lining main reinforcement bars extend out of the lining concrete structure and are fixedly connected to the portal plate. The lining main reinforcement bars serve as the steel skeleton structure of the lining assembly. The ends of the lining main reinforcement bars are welded to the portal plate to form an integral steel skeleton, thus firmly connecting the portal plate to the lining assembly. Simultaneously, the lining main reinforcement bars do not extend into the portal assembly, thus not affecting the demolition and cutting operations of the portal assembly.

[0015] The portal or lining assembly is provided with bolt holes and lifting holes. The bolt holes are mainly used for the connection between adjacent segments; the lifting holes penetrate the concrete structure of the segments and can be used for lifting and assembling the segments. After the segments are lifted and installed, the lifting holes can be used as grouting holes to reinforce the connection between the segments and the ground, thereby enhancing the safety and waterproofing of the construction.

[0016] A method for demolishing a tunnel portal structure involves connecting a heating device to an energy source. The heating device absorbs energy and heats the thermoplastic concrete structure, softening it. Then, the main reinforcing bars are extracted from the grouting hole, and the tunnel boring machine (TBM) cutterhead is used to demolish the portal assembly. The heating device softens the thermoplastic concrete structure, facilitating the rapid extraction of the main reinforcing bars, significantly reducing the structural strength of the portal, minimizing the amount of steel reinforcement to be cut, and making the cutting, demolition, and jacking operations of the tunnel boring machine more efficient. This also reduces cutterhead wear and significantly shortens the construction period.

[0017] The beneficial effects of this invention are: when breaking through the tunnel portal, the main reinforcement bars inside the portal assembly can be extracted first, reducing the structural strength of the portal assembly. Furthermore, the portal assembly with the main reinforcement bars extracted will not cause blockage to the conveyor screw conveyor of the tunnel boring machine after being broken through by the tunnel boring machine, thus ensuring the normal use of the tunnel boring machine and ensuring the efficiency of the tunnel portal breaking.

[0018] Simultaneously, a combination of fixed main reinforcement and detachable portal main reinforcement can be used as the steel structural framework of the portal concrete structure. Removing the portal main reinforcement does not alter the overall structure of the portal component; it retains a certain strength and can temporarily support ground pressure, reducing construction risks and safety hazards during portal demolition. During the early excavation and support stages, the portal main reinforcement can fulfill its load-bearing function, ensuring the safety and stability of the load-bearing structure within the tunnel even before portal demolition.

[0019] The portal components are easier to break after the main reinforcement bars are removed, which can reduce the wear of the roller cutters in the cutterhead. It is even possible to complete the excavation of connecting passages in soft soil strata using only scrapers, which can significantly reduce construction costs. The main reinforcement bars of the lining components are welded to the portal plate and do not intrude into the portal components, which can save steel consumption, enhance the structural strength of the portal, and make it easier to break and cut the portal components.

[0020] Compared with existing technologies, this portal structure allows for the rapid extraction of the main reinforcing bars of the portal via a hot-swappable device, significantly reducing the structural strength of the portal and the amount of steel reinforcement to be cut. This makes it more advantageous for the tunneling machine to cut, demolish, and jack up the portal structure, reducing cutterhead wear and drastically shortening the construction period. It also solves the problems of high cutterhead wear, low tunneling efficiency, and frequent screw conveyor blockages caused by directly cutting the strong reinforced concrete structure of the portal in existing connecting tunnel tunneling machines. Therefore, this solution ensures the safety of the main tunnel interior before connecting tunnel construction, resulting in more efficient, economical, and safer portal demolition.

[0021] In addition, the portal structure can be a portal structure in a connecting passage, a shield launching shaft, or a shield receiving shaft, etc., that is, the portal demolition method is applicable to the demolition of portal structures in the above-mentioned locations. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0024] Figure 2 This is a diagram showing the distribution of the retractable main reinforcement structure inside the tunnel segment;

[0025] Figure 3 This is a schematic diagram showing the distribution of some of the retractable main reinforcement structures within the main tunnel.

[0026] Figure 4 This is a schematic diagram showing the distribution of the main reinforcing bars in the tunnel portal.

[0027] Figure 5 for Figure 4 Detailed schematic diagram of the main reinforcement fixing structure of the central portal;

[0028] Figure 6 This is a schematic diagram of the connection between the thermoplastic structure and the power supply device.

[0029] Figure 7 This is a schematic cross-sectional view of a thermoplastic structure.

[0030] Figure 8 Detailed drawings of the thermoplastic structure and power supply unit;

[0031] Figure 9 Detailed view of the end of the thermoplastic structure;

[0032] Figure 10 Diagram of tunnel segments Figure 1 ;

[0033] Figure 11 Diagram of tunnel segments Figure 2 ;

[0034] Figure 12 This is a schematic diagram of the steel reinforcement distribution in the lining components;

[0035] Figure 13 This is a schematic diagram for alternative embodiment 6;

[0036] Figure 14 This is a schematic diagram for alternative embodiment 7;

[0037] Figure 15 This is a schematic diagram for alternative embodiment 8;

[0038] Figure 16 This is a schematic diagram for alternative embodiment 9;

[0039] Figure 17 This is a schematic diagram of Example 12.

[0040] In the figure: 1. Portal assembly, 11. Portal concrete structure, 13. Portal main reinforcement, 131. Threaded structure, 132. Nut, 14. Thermoplastic structure, 141. Isolation device, 142. Heating device, 143. Thermoplastic concrete structure.

[0041] 2. Lining components; 21. Lining concrete structure; 23. Lifting hole; 24. Grouting hole; 25. Bolt hole; 26. Welding point; 27. Fiberglass reinforcement; 28. Cement mortar.

[0042] 3. Energy device; 31. Power source; 32. Wire;

[0043] 4. Door panel, 41. Reserved hole. Detailed Implementation

[0044] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] Example 1, such as Figures 1-5 As shown, a portal structure includes a portal assembly 1 with a detachable main portal reinforcement 13. The end of the main portal reinforcement 13 extends out of the side of the portal assembly 1. The main portal reinforcement 13 is a steel bar or steel strand, and its specifications are consistent with those of the main reinforcement in conventional shield tunneling portal structures. During tunnel excavation and support, the main portal reinforcement 13 can play its load-bearing role when the tunnel segments are in normal use, ensuring the safety and stability of the load-bearing structure of the tunnel segments in the tunnel when the portal is not breached. When the portal is breached, the main portal reinforcement 13 is pulled out, detaching it from the portal assembly 1, reducing the structural strength of the portal assembly 1. Furthermore, the portal assembly 1 with the main portal reinforcement 13 removed will not cause blockage of the shield machine's conveyor screw conveyor after being breached by the shield machine, ensuring the normal use of the shield machine and guaranteeing the efficiency of the portal breaching.

[0046] Furthermore, the portal assembly 1 includes a portal concrete structure 11, on which a thermoplastic structure 14 is provided. The portal main reinforcement 13 is configured to cooperate with the thermoplastic structure 14 and is disposed within the thermoplastic structure 14. The portal concrete structure 11 uses the same concrete material as conventional shield tunneling portal structures, and the thermoplastic structure 14 is embedded within the portal concrete structure 11.

[0047] Furthermore, such as Figures 6-8As shown, the thermoplastic structure 14 includes an isolation device 141 installed on the portal concrete structure 11. The portal main reinforcement 13 passes through the isolation device 141. The isolation device 141 contains a thermoplastic concrete structure 143, and the thermoplastic concrete structure 143 contains a heating device 142, which is connected to a power supply device. The isolation device 141 can separate the thermoplastic concrete structure 143 from the portal concrete structure 11 during the precast casting of the tunnel segments. In this embodiment, the isolation device 141 is a corrugated pipe with multiple transverse corrugations, allowing the isolation device 141 to fully contact the external portal concrete structure 11. Furthermore, the corrugated pipe is elastic and can displace under pressure, axial force, transverse force, or bending moment. It can deform in tandem with the portal concrete structure 11 under stress, ensuring that the portal main reinforcement 13 encased in the corrugated pipe participates in the stress of the tunnel segments, thus ensuring the safety and stability of the tunnel segments within the tunnel structure. The thermoplastic concrete structure 143, the heating device 142, and the main reinforcement 13 of the tunnel entrance are all located inside the corrugated pipe. The heating device 142 is wrapped around the outside of the main reinforcement 13 of the tunnel entrance and is wrapped together with the main reinforcement 13 of the tunnel entrance by the thermoplastic concrete structure 143.

[0048] Furthermore, the heating device 142 is centrally located within the thermoplastic concrete structure 143 so that when heated by electricity, it can quickly and evenly reach the softening point of the thermoplastic concrete, which is more conducive to the rapid extraction of the main reinforcement 13 of the portal.

[0049] Furthermore, the thermoplastic concrete structure 143 is made of sulfur concrete, which is formed by heating and pouring it into the corrugated pipe. It has good corrosion resistance and density. After being poured into the isolation device 141, it can achieve strong load-bearing performance in a very short time. At the same time, after the main reinforcement 13 of the tunnel portal is pulled out, it can also heat and fill the connection channel left by the pull-out of the main reinforcement 13 of the tunnel portal, and at the same time, it can promptly strengthen the performance of the connection between the tunnel portal and the segment guard plate.

[0050] Furthermore, the thermoplastic concrete structure 143 can be replaced by other thermoplastic materials. The thermoplastic material softens after being heated by the heating device 142, which enables the main reinforcement 13 of the opening to be pulled out. Specifically, the thermoplastic material is polyvinyl chloride (PVC), polypropylene (PP), polychloroprene (PVC-b), or polyaryletherketone (PAEK) material.

[0051] Furthermore, such as Figure 7 As shown, the heating device 142 is a resistance wire structure, which is embedded in the sulfur concrete material in the isolation device 141. It is powered by a power supply device, and the current passes through the resistive body to generate a heating effect. Under the action of heat radiation, heat conduction and heat convection, the sulfur concrete material becomes plastic / fluid, and at this time the main reinforcement 13 of the tunnel can be pulled out smoothly.

[0052] Furthermore, the power supply device includes a power source 31 and a wire 32. The power source 31 is connected to the resistance wire through the wire 32. The power source 31 supplies power to the resistance wire. The power source 31 is a mobile power source or a power source carried on the tunnel boring machine equipment.

[0053] In Example 2, based on Example 1, the portal assembly 1 is further provided with fixed main reinforcement bars, which are embedded within the portal concrete structure 11. The fixed main reinforcement bars and the detachable portal main reinforcement bars 13 are arranged alternately, i.e., the fixed main reinforcement bars and the portal main reinforcement bars 13 are combined to form the steel frame structure of the portal concrete structure 11. Even when the tunneling machine support device fails to provide sufficient support, the portal structure can still maintain its stability before tunneling by temporarily pulling out the portal main reinforcement bars 13. This ensures that the overall structure of the portal assembly 1 after the portal main reinforcement bars 13 are pulled out does not change, and it still possesses a certain strength, capable of temporarily supporting ground pressure, reducing construction risks during portal breaching, and minimizing construction safety hazards.

[0054] Example 3, based on Example 1 or Example 2, such as Figure 10 , Figure 11 As shown, a lining component 2, matching the portal component 1, is connected to the side of the portal component 1. The lining component 2 has a grouting hole 24, and the main reinforcement 13 of the portal extends out of the lining component 2 from the grouting hole 24. The end of the main reinforcement 13 has a fixing structure that cooperates with the lining component 2. The portal component 1 and the lining component 2 are integrally cast. The grouting hole 24 is the channel formed by the isolation device embedded in the portal concrete structure 11, serving as the channel for grouting thermoplastic concrete during segment fabrication. Specifically, during segment prefabrication, sulfur concrete material is injected into the isolation device 141 through the grouting hole 24, completely encasing the main reinforcement 13 of the portal and the heating device 142 inside the isolation device 141 in the sulfur concrete material. The main reinforcement 13 is fixed to the inner wall of the segment by the fixing structure.

[0055] Furthermore, such as Figure 5 , Figure 9 As shown, the fixing structure includes a threaded structure 131 at the end of the main reinforcement 13 of the tunnel portal, with a nut 132 connected to the threaded structure 131 to mate with the lining component 2. The end of the main reinforcement 13 of the tunnel portal is fixed to the inner side of the lining component 2. When the heating device 142 melts the thermoplastic concrete structure 143, the fixing device can be pulled out together with the main reinforcement 13 of the tunnel portal. The connection between the nut 132 and the threaded structure 131 strengthens the anchoring effect of the main reinforcement 13 of the tunnel portal to the concrete structure 11 of the tunnel portal, ensuring that the concrete structure 11 of the tunnel portal does not detach from the lining component 2 under its own weight and ground load, thus guaranteeing the structural stability of the tunnel portal component 1.

[0056] Example 4 differs from Example 3 in that the fixing structure includes an anchoring joint at the end of the main reinforcement bar 13 of the tunnel portal. The anchoring joint is equipped with an anchor plate and a clamp. The main reinforcement bar 13 of the tunnel portal is a steel strand. When the thermoplastic concrete structure 143 is poured, after the thermoplastic concrete structure 143 has solidified and stabilized, the steel strand is clamped by the clamp and placed on the anchor plate to fix the end of the main reinforcement bar 13 of the tunnel portal.

[0057] In Example 5, based on Example 4, a portal plate 4 is provided between the portal assembly 1 and the lining assembly 2. The portal plate 4 has pre-drilled holes 41 through which the main portal reinforcement 13 passes. After passing through the pre-drilled holes 41, the main portal reinforcement 13 connects to the lining assembly 2, forming the skeleton structure of the portal assembly 1. The portal plate 4 is either an arc-shaped plate or a flat plate, and multiple portal plates 4 are spliced ​​together to form a ring structure. In this example, the portal plate 4 is an arc-shaped plate. After the tunnel segments are assembled, six tunnel segments are installed in a staggered arrangement, and the arc-shaped plates on the six tunnel segments are spliced ​​together to form a ring structure. The portal assembly 1 is in the middle of the ring structure, and the lining assembly 2 is on the outer side of the ring structure.

[0058] Furthermore, such as Figure 12 As shown, the lining component 2 includes a lining concrete structure 21 and lining main reinforcement embedded in the lining concrete structure 21. The ends of the lining main reinforcement extend out of the lining concrete structure 21 and are fixedly connected to the portal plate 4. The lining main reinforcement, portal plate 4, and portal main reinforcement 13 together constitute the skeleton structure of the tunnel segment. The lining main reinforcement is only set in the lining concrete structure 21 and is cut off and welded at the portal plate 4. The lining main reinforcement is not inserted into the portal concrete structure 11 and will not affect the demolition and cutting operations of the portal. The ends of the lining main reinforcement are welded to the portal plate 4 at welding point 26. The skeleton structure fully ensures the stress performance of the tunnel segment structure in all aspects, so that the tunnel segment meets the usage requirements and ensures the safety of tunnel segment construction inside the tunnel.

[0059] Furthermore, the portal assembly 1 or lining assembly 2 is provided with bolt holes 25 and lifting holes 23. Bolt holes 25 are mainly used for the connection between adjacent segments; lifting holes 23 penetrate the segments, facilitating the lifting and assembly of segments. After the segments are lifted and installed, lifting holes 23 can be used as grouting holes to reinforce the connection between the segments and the stratum, enhancing construction safety and waterproofing.

[0060] Example 6 differs from Example 3 in that, as Figure 13As shown, the tunnel segment is equipped with portal main reinforcement 13, lining main reinforcement and glass fiber reinforcement 27. The portal main reinforcement 13, lining main reinforcement and glass fiber reinforcement 27 together form the steel skeleton structure of the tunnel segment. When the connecting passage is excavated, the portal main reinforcement 13 can be removed. The lining main reinforcement and glass fiber reinforcement 27 left in the tunnel segment can still provide good support, so that the tunnel segment can remain stable before excavation, thereby providing safety for the portal breaking construction.

[0061] Example 7 differs from Example 1 in that, as Figure 14 As shown, the portal assembly 1 is constructed by multi-layer casting of the portal concrete structure 11 and the thermoplastic concrete structure 143, forming a layered structure. The main reinforcement 13 and the heating device 142 are cast within the thermoplastic concrete structure 143. When the heating device 142 is energized, it heats and softens the thermoplastic concrete structure 143, allowing the main reinforcement 13 to be extracted from it. This reduces the structural strength of the portal assembly 1, making it easier to break and cut.

[0062] Example 8 differs from Example 1 in that, as Figure 15 As shown, the portal component 1 includes a portal concrete structure 11. The portal concrete structure 11 has multiple elongated holes arranged side by side. The elongated holes are filled with thermoplastic concrete structures 143. An isolation device is provided between the portal concrete structure 11 and the thermoplastic concrete structure 143. The thermoplastic concrete structure 143 is embedded with a portal main reinforcement 13 and a heating device 142. When the heating device 142 is powered on, it heats the thermoplastic concrete 143 to soften it, and the portal main reinforcement 13 can be extracted from the thermoplastic concrete structure 143. This can reduce the structural strength of the portal component 1 and make it easier to break and cut the portal component 1.

[0063] Example 9 differs from Example 1 in that, as Figure 16 As shown, the portal assembly 1 includes a portal concrete structure 11, with a thermoplastic concrete outer shell on the outside of the portal concrete structure 11. The main reinforcement 13 and the heating device 142 are located on the outside of the portal concrete structure 11 and embedded in the thermoplastic concrete structure 143. When the heating device 142 is powered on, it heats and softens the thermoplastic concrete 143, allowing the main reinforcement 13 to be extracted from the thermoplastic concrete structure 143. This reduces the structural strength of the portal assembly 1, making it easier to break and cut the portal assembly 1.

[0064] Example 10 differs from Example 1 in that, as Figure 2 , Figure 4As shown, the main reinforcement bars 13 inside the portal assembly 1 are arranged in two layers, inner and outer. The upper end of the main reinforcement bars 13 extends out of the portal concrete structure 11 and then bends. The end of the outer main reinforcement bar 13 is welded to the inner main reinforcement bar 13. The end of the inner main reinforcement bar 13 extends out from the inner wall of the lining assembly 2. When the main reinforcement bars are pulled out, the end of the inner main reinforcement bar 13 is pulled out, and the main reinforcement bars 13 of both the inner and outer layers can be pulled out at the same time, which improves the extraction efficiency of the main reinforcement bars 13 and improves the construction efficiency.

[0065] Example 11, based on Example 1, provides a method for breaking a tunnel portal structure. When breaking the tunnel portal, the heating device 142 is first connected to the energy device. After absorbing energy, the heating device 142 heats the thermoplastic concrete structure 143, softening it and allowing the main reinforcement 13 of the tunnel portal to be extracted. Then, the tunnel portal assembly 1 is broken by pushing in the cutterhead of the tunnel boring machine. Specifically, the energy device is a power supply device. The power supply 31 of the power supply device 3 is connected to the heating device 142 through the wire 32. After the resistance wire of the heating device 142 is energized, it will generate a heat effect, thereby heating the thermoplastic concrete structure 143. Under the action of heat radiation and heat conduction, the thermoplastic concrete structure 143 becomes a plastic or fluid state. Then, by pulling the end of the main reinforcement 13 of the tunnel portal, the main reinforcement 13 of the tunnel portal is pulled out from the grouting hole 24 on the lining component 2, so that the main reinforcement 13 of the tunnel portal is separated from the tunnel portal concrete structure 11. The removal of the main reinforcement 13 of the tunnel portal weakens the structural strength of the tunnel portal component 1, which is more conducive to the tunnel portal cutting operation of the tunnel boring machine. After the main reinforcement 13 of the tunnel portal is removed, the strength of the tunnel portal component 1 is reduced, reducing the amount of steel bars that need to be cut during the tunnel portal demolition. This is more conducive to the tunnel boring machine to cut, demolish, and jack the tunnel portal component 1 of the tunnel segments, reducing cutterhead wear and significantly shortening the construction period.

[0066] Furthermore, when pulling out the main reinforcement 13 of the tunnel portal, the support trolley or tunnel support device can be supported on the main tunnel segment to reduce or eliminate the tension state of the main reinforcement 13 of the tunnel portal assembly 1. At this time, it is safer and more reasonable to carry out the subsequent heating of the thermoplastic concrete structure 143 and the pulling out of the main reinforcement 13 of the tunnel portal.

[0067] In Example 12, based on Example 11, when removing the main reinforcement bar 13 of the tunnel portal, it is pulled out to a position that does not affect the demolition of the tunnel portal, i.e., the main reinforcement bar 13 is detached from the tunnel portal assembly 1. At this time, part of the main reinforcement bar 13 is located inside the lining assembly 2, and the other part extends out of the inner side of the lining assembly 2. Then, the part of the main reinforcement bar 13 extending out of the inner side of the lining assembly 2 is cut off, so that the main reinforcement bar 13 is still retained inside the lining assembly 2. Cement mortar 28 is then filled into the grouting hole 24 on the lining assembly 2, sealing the grouting hole 24. The main reinforcement bar 13 retained inside the lining assembly 2 ensures the structural integrity and stability of the lining assembly, while the cement mortar 28 seals the thermoplastic concrete structure 143, ensuring its fire resistance stability during later operation.

[0068] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A portal structure, characterized in that, Includes a portal assembly (1), on which a detachable portal main reinforcement (13) is provided, the end of which extends out of the side of the portal assembly (1); The portal assembly (1) includes a portal concrete structure (11), on which a thermoplastic structure (14) is provided, and the portal main reinforcement (13) is provided in conjunction with the thermoplastic structure (14); The thermoplastic structure (14) includes an isolation device (141) installed on the portal concrete structure (11), the portal main reinforcement (13) passes through the isolation device (141), the isolation device (141) is provided with a thermoplastic concrete structure (143), and the thermoplastic concrete structure (143) is provided with a heating device (142).

2. The portal structure according to claim 1, characterized in that, The portal assembly (1) is also equipped with a fixed main reinforcement bar, which is embedded in the portal concrete structure (11).

3. The portal structure according to claim 1 or 2, characterized in that, The portal assembly (1) is connected to a lining assembly (2) that matches the portal assembly (1). The lining assembly (2) is provided with a grouting hole (24). The main reinforcement (13) of the portal extends out of the lining assembly (2) from the grouting hole (24). The end of the main reinforcement (13) of the portal is provided with a fixing structure that cooperates with the lining assembly (2).

4. The portal structure according to claim 3, characterized in that, The fixing structure includes a threaded structure (131) set at the end of the main reinforcement (13) of the tunnel entrance, and a nut (132) is connected to the threaded structure (131).

5. The portal structure according to any one of claims 1, 2, and 4, characterized in that, A portal plate (4) is provided between the portal assembly (1) and the lining assembly (2). A reserved hole (41) is provided on the portal plate (4), and the main reinforcement (13) of the portal passes through the reserved hole (41).

6. The portal structure according to claim 5, characterized in that, The door panel (4) is an arc-shaped panel or a flat panel, and multiple door panels (4) are spliced ​​together to form a ring structure.

7. The portal structure according to claim 6, characterized in that, The lining component (2) includes a lining concrete structure (21) and lining main reinforcement embedded in the lining concrete structure (21). The ends of the lining main reinforcement extend out of the lining concrete structure (21) and are fixedly connected to the portal plate (4).

8. A method for breaking through a portal structure as described in any one of claims 1 to 7, characterized in that, Before the tunnel portal is broken, the heating device (142) is connected to the energy device (3). After the heating device (142) absorbs energy, it heats the thermoplastic concrete structure (143) to make it soft. Then the main reinforcement (13) of the tunnel portal is pulled out, and then the shield machine cutterhead is pushed in to break the tunnel portal component (1).

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