Tunnel sprayed concrete steam curing device and method

Abstract

The invention discloses a tunnel shotcrete steam curing device and method, and relates to the technical field of tunnel construction, the tunnel shotcrete steam curing device comprises a portal frame system and a sealing system, the sealing system comprises supporting beams, a sealing telescopic film and a sealing air bag, and the supporting beams are arranged in the circumferential direction of the portal frame system and extend in the axial direction; the supporting beam is connected with the portal frame system through a radial telescopic mechanism, a sealing telescopic film is arranged on the supporting beam, and the sealing telescopic film is distributed in the circumferential direction wrapping the portal frame system and can be unfolded along with extension of the radial telescopic mechanism; a sealing air bag is arranged around the edge of the sealing telescopic film; after the closed system is unfolded, the two sides of the closed air bag abut against the supporting beam and the sprayed concrete layer on the inner wall of the tunnel correspondingly, and the closed air bag, the sealing telescopic film and the sprayed concrete layer define a sealed steam cavity. By the adoption of the radial telescopic mechanism, the tunnel maintenance device can be matched with the tunnel in size during maintenance operation, the operation requirement is met, the occupied space can be reduced during non-maintenance operation, and transportation and storage are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction, and particularly to a steam curing device and method for tunnel shotcrete. Background Art

[0002] Due to limitations in material quality, casting process and tooling, and maintenance level, quality problems of tunnel lining such as lining cracking, spalling of the arch part, and block falling often occur. The performance of lining concrete is mainly determined by factors such as the components of concrete raw materials, concrete mixing and casting process, and concrete maintenance. Given certain concrete raw materials, mix ratio, and construction process, the maintenance of concrete, especially the control of early maintenance methods, maintenance temperature, maintenance humidity, maintenance time, etc., has an important impact on the degree of concrete hydration and hardening, strength development, durability, etc. The maintenance temperature has a great influence on the development speed of the early performance of concrete. Research has shown that the higher the early maintenance temperature of concrete, the faster the strength development. When the temperature is lower than a certain limit value, the cement hydration reaction will no longer proceed, and the concrete strength will stop developing. In fact, when the temperature is lower than 0°C, the water in the concrete has already started to freeze, which will cause freeze damage to the concrete. At the same time, if the environment where the early concrete is located does not maintain sufficient humidity, a large amount of water in the concrete may evaporate. The consequences are as follows: on the one hand, the continued hydration of cement is affected due to drying and water loss; on the other hand, the drying shrinkage of the concrete increases, causing the concrete to bear the tensile stress caused by shrinkage in the low-strength state, resulting in early cracks in the concrete.

[0003] Currently, steam curing is widely used due to its advantages such as short curing time, high curing efficiency, strong adaptability, energy conservation and environmental protection. However, in some technical solutions, existing steam curing trolleys mostly use steel arch frames to support the sealed steam chamber. Due to their large volume, they not only have extremely strict requirements for the transportation process, but also have great limitations on construction sites, etc. Summary of the Invention

[0004] The purpose of the present invention is to provide a steam curing device and method for tunnel shotcrete to solve the problems existing in the above-mentioned prior art, which can match the tunnel size during curing operations to meet the operation requirements, and can reduce the occupied space during non-curing operations, facilitating transportation and storage.

[0005] To achieve the above purpose, the present invention provides the following solutions: A steam curing device for shotcrete in tunnels, comprising a gantry system and a closing system. The closing system includes a support beam, a sealing expansion membrane, and a closing airbag. The support beam is arranged circumferentially along the gantry system and extends axially along the gantry system. The support beam is connected to the gantry system through a radial expansion mechanism, and the radial expansion mechanism can expand and contract radially along the gantry system. The sealing expansion membrane is arranged on the support beam, and the sealing expansion membrane is distributed circumferentially around the gantry system and can be unfolded as the radial expansion mechanism elongates. The closing airbag is arranged along the edge of the sealing expansion membrane for one week. After the closing system is unfolded, both sides of the closing airbag are respectively abutted against the support beam and the shotcrete layer applied on the inner wall of the tunnel. The sealing expansion membrane, the closing airbag, and the shotcrete layer enclose and form a sealed steam chamber. The sealing expansion membrane is provided with a steam inlet hole for the steam generating device to communicate with the sealed steam chamber.

[0006] In an exemplary embodiment, the gantry system includes at least two plane frames. At least two plane frames are arranged along the extension direction of the tunnel and are sequentially connected by longitudinal beams. The plane frame includes at least two sets of unit structures arranged in sequence from bottom to top. The unit structure includes two vertical beams and one cross beam, and one cross beam is fixedly arranged on the tops of the two vertical beams.

[0007] In an exemplary embodiment, from bottom to top, the distance between the two vertical beams in at least two sets of the unit structures decreases sequentially.

[0008] In an exemplary embodiment, the longitudinal beam is fixedly connected to the vertical beam or the cross beam, and the support beam is installed on the longitudinal beam fixedly connected to the vertical beam through the radial expansion mechanism.

[0009] In an exemplary embodiment, it further includes a steam generating device arranged on the gantry system. The steam generating device is communicated with the steam inlet hole through a pipeline.

[0010] In an exemplary embodiment, a plurality of working platforms for operators to step on and work are arranged on the gantry system.

[0011] In an exemplary embodiment, a traveling mechanism is arranged at the bottom of the gantry system.

[0012] In an exemplary embodiment, the support beam is a telescopic structure that can expand and contract axially along the gantry system. As the support beam elongates, the sealing expansion membrane arranged on the support beam can be unfolded axially along the gantry system.

[0013] In an exemplary embodiment, the support beam includes an inner tube and an outer tube that are slidably sleeved with each other. One end of the outer tube is provided with an axial telescopic mechanism, and the telescopic direction of the axial telescopic mechanism is consistent with the extending direction of the support beam. The fixed end of the axial telescopic mechanism is fixedly connected to the outer tube, and the movable end is fixedly connected to the inner tube. Both the outer tube and the fixed end of the axial telescopic mechanism are connected to the gantry system through the radial telescopic mechanism.

[0014] The present invention also provides a method for steam curing of tunnel shotcrete, which uses the above-mentioned tunnel shotcrete steam curing device and includes the following steps: S1. Tunnel excavation is carried out, and shotcrete is applied to the inner wall of the tunnel to form an initial support layer. S2. The tunnel shotcrete steam curing device arrives at the position. The radial telescopic mechanism on the gantry system extends, driving the support beam and the sealing telescopic membrane to approach the shotcrete layer applied to the inner wall of the tunnel. S3. After the radial telescopic mechanism extends to the in-place position, the closed airbag is inflated until it abuts against the shotcrete layer, and the sealing telescopic membrane, the closed airbag, and the shotcrete layer surround and form a sealed steam chamber. S4. Steam is filled into the sealed steam chamber through the steam generating device to start the curing of the shotcrete. S5. After the curing is completed, the closed airbag is deflated, the radial telescopic mechanism contracts, and the sealing telescopic membrane contracts accordingly and returns to the outer periphery of the gantry system.

[0015] The present invention has achieved the following technical effects compared with the prior art: By providing a support beam arranged circumferentially along the gantry system and extending axially, a sealing telescopic membrane is provided on the support beam, and the sealing telescopic membrane is distributed circumferentially along the periphery of the gantry system. A closed airbag is arranged along the edge of the sealing telescopic membrane for one week: during the curing operation, the radial telescopic mechanism extends radially along the gantry system, and the sealing telescopic membrane unfolds as the radial telescopic mechanism extends. After the closed airbag is inflated, it abuts against the shotcrete layer applied on the inner wall of the tunnel, that is, the whole device extends to match the size of the tunnel, and then the sealing telescopic membrane, the closed airbag, and the shotcrete layer surround and form a sealed steam chamber; during non-curing operations, the radial telescopic mechanism is in a contracted state, and the support beam, the sealing telescopic membrane, and the closed airbag are all retracted from the state matching the size of the tunnel and are compactly arranged around the gantry system, reducing the occupied space during transportation and storage.

[0016] The other technical solutions disclosed by the present invention also have the following technical advantages: By setting the support beam as a telescopic structure that can be telescoped along the axial direction of the gantry system, the closed system can not only match the tunnel size in the radial direction, but also increase the extension length in the axial direction of the tunnel, increase the one-time maintenance area, further improve the maintenance efficiency, shorten the maintenance time, and will not additionally increase the transportation and storage burden. Brief Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 Structural schematic diagram of the tunnel shotcrete steam curing device disclosed in a specific embodiment of the present invention; Figure 2 For Figure 1 Structural schematic diagram after removing the sealing telescopic film and the closed airbag; Wherein, 1. Gantry system; 2. Closed system; 3. Sealing telescopic film; 4. Closed airbag; 5. Cross beam; 6. Vertical beam; 7. Working platform; 8. Radial telescopic mechanism; 9. Axial telescopic mechanism; 10. Support beam; 11. Longitudinal beam; 12. Traveling mechanism; 13. Diagonal support beam. Detailed Embodiments

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Those skilled in this technology can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0020] It should be noted that the structures, ratios, sizes, etc. depicted in the accompanying drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limiting conditions under which the present invention can be implemented. Therefore, they do not have substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention. In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation to the present invention. In addition, terms such as "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0021] It should also be noted that in the embodiments of the present application, the same reference numerals are used to represent the same component or the same part.

[0022] The object of the present invention is to provide a steam curing device and method for tunnel shotcrete, so as to solve the problems existing in the prior art. It can match the tunnel size during the curing operation to meet the operation requirements, and can also reduce the occupied space during non-curing operations, facilitating transportation and storage.

[0023] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Embodiment 1 Please refer to Figures 1 to 2, this embodiment provides a steam curing device for tunnel shotcrete, which includes a gantry system 1 and a sealing system 2. The sealing system 2 includes a support beam 10, a sealing expansion membrane 3, and a sealing airbag 4. The support beam 10 is arranged along the circumference of the gantry system 1 and extends along the axial direction of the gantry system 1. The support beam 10 is connected to the gantry system 1 through a radial expansion mechanism 8, and the radial expansion mechanism 8 can expand and contract along the radial direction of the gantry system 1. A sealing expansion membrane 3 is arranged on the support beam 10, and the sealing expansion membrane 3 is distributed along the circumference covering the gantry system 1 and can be unfolded as the radial expansion mechanism 8 elongates. A sealing airbag 4 is arranged around the edge of the sealing expansion membrane 3. After the sealing system 2 is unfolded, both sides of the sealing airbag 4 are respectively abutted against the support beam 10 and the shotcrete layer applied on the inner wall of the tunnel. The sealing expansion membrane 3, the sealing airbag 4, and the shotcrete layer enclose to form a sealed steam chamber, and a steam inlet hole for connecting the steam generating device to the sealed steam chamber is opened on the sealing expansion membrane 3.

[0025] The working principle of this embodiment is as follows: During the curing operation, the radial expansion mechanism 8 expands along the radial direction of the gantry system 1, and the sealing expansion membrane 3 is unfolded as the radial expansion mechanism 8 elongates. After the sealing airbag 4 arranged around the edge of the sealing expansion membrane 3 is inflated, both sides are respectively abutted against the support beam 10 and the shotcrete layer applied on the inner wall of the tunnel, that is, the whole device extends to match the size of the tunnel, and then the sealing expansion membrane 3, the sealing airbag 4, and the shotcrete layer enclose to form a sealed steam chamber. Then, the steam generating device injects steam into the sealed steam chamber through the steam inlet hole to start the curing operation.

[0026] As Figure 1 shown, the sealing airbags 4 located on both radial sides of the gantry system 1 extend along the axial direction of the gantry system 1. Along the length direction of this section of the sealing airbag 4, it can be kept in contact with the support beam 10 and the shotcrete layer throughout the whole process, which can effectively ensure the sealing effect. And the sealing airbags 4 located on both axial sides of the gantry system 1 extend along the circumferential direction of the gantry system 1. Along the length direction of this section of the sealing airbag 4, the outer side is kept in contact with the shotcrete layer throughout the whole process, and the inner side is in intermittent point contact with the support beam 10. Relying on the high pressure inside the sealing airbag 4, under the supporting action of the intermittent point contact, the effective sealing can also be ensured. Of course, in order to further enhance the sealing effect, the number of support beams 10 can be appropriately increased, so as to increase the support points of the sealing airbags 4.

[0027] During non-curing operations, the radial telescopic mechanism 8 is in a retracted state. The support beam 10, the sealed telescopic membrane 3, and the closed airbag 4 are all retracted from the state matching the tunnel size and are tightly arranged around the gantry system 1, thereby reducing the occupied space during transportation and storage. At this time, the overall radial dimension of the steam curing device is the radial dimension of the gantry system 1 plus the length of the radial telescopic mechanism 8 (the thickness dimensions of the sealed telescopic membrane 3 and the closed airbag 4 in the retracted state can be ignored). Therefore, the shorter the radial telescopic mechanism 8 can retract, the smaller the overall occupied space of the steam curing device, and the lower the requirements for transportation, storage, and the construction site.

[0028] As a preferred solution of this embodiment, the support beam 10 is a telescopic structure that can telescopically extend along the axial direction of the gantry system 1. As the support beam 10 extends, the sealed telescopic membrane 3 provided on the support beam 10 can also be unfolded along the axial direction of the gantry system 1.

[0029] By setting the support beam 10 as a telescopic structure that can telescopically extend along the axial direction of the gantry system 1, the closed system 2 can not only be matched with the tunnel size in the radial direction but also increase the extended length in the axial direction of the tunnel, increase the one-time curing area, further improve the curing efficiency, shorten the curing time, and will not additionally increase the transportation and storage burden.

[0030] Specifically, the support beam 10 includes an inner tube and an outer tube that are slidably sleeved with each other. One end of the outer tube is provided with an axial telescopic mechanism 9, and the telescopic direction of the axial telescopic mechanism 9 is consistent with the extending direction of the support beam 10. The fixed end of the axial telescopic mechanism 9 is fixedly connected to the outer tube, the movable end is fixedly connected to the inner tube, and both the outer tube and the fixed end of the axial telescopic mechanism 9 are connected to the gantry system 1 through the radial telescopic mechanism 8.

[0031] The gantry system 1 includes at least two plane frames, and the at least two plane frames are arranged along the extending direction of the tunnel and are sequentially connected by longitudinal beams 11. The plane frame includes at least two groups of unit structures arranged in sequence from bottom to top. The unit structure includes two vertical beams 6 and one cross beam 5, and one cross beam 5 is fixedly arranged on the tops of the two vertical beams 6. And, from bottom to top, the distance between the two vertical beams 6 in at least two groups of unit structures decreases sequentially.

[0032] The longitudinal beam 11 can be fixedly connected to the vertical beam 6 or can be fixedly connected to the cross beam 5. To ensure the overall stability of the gantry system 1, multiple longitudinal beams 11 may be horizontally laid or vertically laid between the cross beams 5 and the vertical beams 6 of adjacent two plane frames, and diagonal bracing beams 13 can be provided between the cross beams 5 and the vertical beams 6 of the same plane frame to increase the strength.

[0033] To ensure the stability of the extension and retraction of the support beam 10, the same support beam 10 can be connected to the gantry system 1 through multiple radial expansion and contraction mechanisms 8. To facilitate the installation of the multiple radial expansion and contraction mechanisms 8, the support beam 10 is preferably installed on the longitudinal beam 11 fixedly connected to the vertical beam 6 through the radial expansion and contraction mechanisms 8. Specifically, the fixed end of the radial expansion and contraction mechanism 8 can be fixedly connected to the longitudinal beam 11, and the support beam 10 is installed at the movable end of the radial expansion and contraction mechanism 8.

[0034] When the closed system 2 is deployed, the extension amount of the radial expansion and contraction mechanism 8 can be adjusted according to the actual tunnel size, so as to adapt to tunnel working conditions of various shapes and sizes. The distance between two vertical beams 6 in at least two sets of unit structures decreases successively. Moreover, the support beam 10 is installed on the longitudinal beam 11 fixedly connected to the vertical beam 6 through the radial expansion and contraction mechanism 8. In this way, the initial shape formed by surrounding of multiple support beams 10 fits the arched tunnel, and the difference in the extension amounts of the multiple radial expansion and contraction mechanisms 8 is minimized to reduce the adjustment error. Similarly, the combination mode of the gantry system 1, as well as the installation positions of the support beam 10 and the radial expansion and contraction mechanism 8, can be adjusted according to tunnels of different shapes.

[0035] As a preferred solution of this embodiment, a traveling mechanism 12 is arranged at the bottom of the gantry system 1, and a steam generating device is arranged on the gantry system 1. The steam generating device is communicated with the steam inlet hole through a pipeline. Meanwhile, a plurality of working platforms 7 are also arranged on the gantry system 1 for operators to step on for work. The working platforms 7 are preferably installed on the gantry system 1 in a detachable manner to ensure that they will not cause obstruction and interference to the sealing expansion membrane 3 when the radial expansion and contraction mechanism 8 contracts.

[0036] The sealing expansion membrane 3 is specifically a foldable and telescopic flexible membrane body, and the specific material can be rubber, such as a rubber expansion membrane. The closed airbag 4 can also be a sealed bag made of rubber material. Of course, the materials and structural forms of the sealing expansion membrane 3 and the closed airbag 4 are not limited to the above-listed cases, and any structure and material in the prior art that can achieve the same function can also be adopted.

[0037] Embodiment Two This embodiment provides a method for steam curing of shotcrete in a tunnel, using the tunnel shotcrete steam curing device described in Embodiment One, including the following steps: S1. The tunnel is excavated, and shotcrete is applied to the inner wall of the tunnel to form an initial support layer. S2. The tunnel shotcrete steam curing device arrives in place. The radial expansion and contraction mechanism 8 on the gantry system 1 extends, driving the support beam 10 and the sealing expansion membrane 3 to approach the shotcrete layer constructed on the inner wall of the tunnel in the radial direction; the axial expansion and contraction mechanism 9 extends, driving the support beam 10 to elongate, and further driving the sealing expansion membrane 3 to cover a larger area of the shotcrete layer in the axial direction. After the radial expansion mechanism 8 and the axial expansion mechanism 9 reach the end of elongation, the closed airbag 4 is inflated until the closed airbag 4 abuts against the shotcrete layer, and a sealed steam chamber is formed by enclosing the sealing expansion membrane 3, the closed airbag 4, and the shotcrete layer; S4. Fill the sealed steam chamber with steam through the steam generating device to start the curing of the shotcrete; S5. After the curing is completed, deflate the closed airbag 4, contract the radial expansion mechanism 8 and the axial expansion mechanism 9, and the sealing expansion membrane 3 contracts accordingly and returns to the outer periphery of the gantry system 1.

[0038] In the description of the present application, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0039] If the present invention discloses or involves components or structural parts that are fixedly connected to each other, then, unless otherwise stated, the fixed connection can be understood as: a detachable fixed connection (such as using bolts or screws for connection), or it can also be understood as: a non-detachable fixed connection (such as riveting or welding). Of course, the mutually fixed connection can also be replaced by an integral structure (such as being integrally formed by using a casting process) (except when it is obviously impossible to adopt the integral forming process).

[0040] In addition, for any technical solution disclosed in the present invention above, the terms used to represent the positional relationship or shape, unless otherwise stated, include states or shapes that are approximate, similar, or close to it.

[0041] Any component provided by the present invention can either be assembled from multiple separate components or be a single component manufactured by an integral forming process.

[0042] Adaptations made according to actual needs are all within the protection scope of the present invention.

[0043] It should be noted that for those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention. Any reference signs in the claims should not be construed as limiting the claims involved.

[0044] Specific examples are used in the present invention to illustrate the principles and implementation manners of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention. At the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A steam curing device for tunnel shotcrete, characterized in that: The invention comprises a gantry system and a closed system, wherein the closed system comprises a support beam, a sealing telescopic film and a closed airbag, wherein the support beam is arranged along the circumference of the gantry system and extends along the axial direction of the gantry system; the support beam is connected to the gantry system through a radial telescopic mechanism, and the radial telescopic mechanism can be telescoped in the radial direction of the gantry system; the support beam is provided with the sealing telescopic film, which is distributed along the circumference of the gantry system and can be unfolded as the radial telescopic mechanism is extended; the closed airbag is arranged around the edge of the sealing telescopic film; after the closed system is unfolded, the two sides of the closed airbag are respectively in contact with the support beam and the sprayed concrete layer applied on the inner wall of the tunnel, and the sealing telescopic film, the closed airbag and the sprayed concrete layer surround and form a sealed steam chamber; the sealing telescopic film is provided with a steam inlet hole for a steam generating device to communicate with the sealed steam chamber.

2. The tunnel shotcrete steam curing device according to claim 1 is characterized in that: The gantry system includes at least two planar frames, which are arranged along the extension direction of the tunnel and connected in sequence through longitudinal beams; the planar frames include at least two groups of unit structures arranged in sequence from bottom to top, and the unit structures include two vertical beams and one horizontal beam, and one horizontal beam is fixedly arranged on the top of the two vertical beams.

3. The tunnel shotcrete steam curing device according to claim 2 is characterized in that: From bottom to top, the distance between the two vertical beams in at least two groups of the unit structures decreases successively.

4. The tunnel shotcrete steam curing device according to claim 3 is characterized in that: The longitudinal beam is fixedly connected to the vertical beam or the horizontal beam, and the support beam is installed on the longitudinal beam fixedly connected to the vertical beam through the radial telescopic mechanism.

5. The tunnel shotcrete steam curing device according to claim 1, characterized in that: It also includes a steam generating device arranged on the gantry system, and the steam generating device is connected with the steam inlet hole through a pipeline.

6. The tunnel shotcrete steam curing device according to claim 1, characterized in that: The gantry system is provided with a plurality of working platforms for workers to step on and work.

7. The tunnel shotcrete steam curing device according to claim 1, characterized in that: A walking mechanism is arranged at the bottom of the portal system.

8. The steam curing device for tunnel shotcrete according to any one of claims 1 to 7, characterized in that: The support beam is a telescopic structure that can be telescoped along the axial direction of the portal system. As the support beam is extended, the sealing telescopic film arranged on the support beam can be expanded along the axial direction of the portal system.

9. The tunnel shotcrete steam curing device according to claim 8, characterized in that: The support beam includes an inner tube and an outer tube which are slidably mounted on each other. An axial telescopic mechanism is provided at one end of the outer tube, and the telescopic direction of the axial telescopic mechanism is consistent with the extension direction of the support beam; the fixed end of the axial telescopic mechanism is fixedly connected to the outer tube, and the movable end is fixedly connected to the inner tube; the fixed ends of the outer tube and the axial telescopic mechanism are both connected to the gantry system through the radial telescopic mechanism.

10. A method for steam curing of tunnel shotcrete, characterized in that: The tunnel shotcrete steam curing device according to any one of claims 1 to 9 comprises the following steps: S1. Tunnel excavation, spraying concrete on the inner wall of the tunnel to form the initial support layer; S2. The steam curing device for shotcrete in the tunnel is in place, and the radial telescopic mechanism on the gantry system extends out, driving the support beam and the sealing telescopic membrane to approach the shotcrete layer applied on the inner wall of the tunnel; S3, after the radial telescopic mechanism is extended to the right position, the closed airbag is inflated until the closed airbag abuts against the shotcrete layer, and the sealed telescopic film, the closed airbag and the shotcrete layer surround to form a sealed steam chamber; S4, filling the sealed steam chamber with steam through the steam generating device to start curing of the shotcrete; S5. After the curing is completed, the closed airbag is deflated, the radial telescopic mechanism is contracted, and the sealing telescopic film is contracted accordingly and returns to the periphery of the gantry system.

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