CN117662195A - Pre-buried steel ring, tunnel portal receiving structure and shield tunnel portal reinforcing method - Google Patents

Abstract

The invention belongs to the technical field of shield construction, and discloses a pre-buried steel ring, a tunnel portal receiving structure and a shield tunnel portal reinforcing method, wherein the pre-buried steel ring comprises a steel ring body, wherein the steel ring body is provided with a freezing sleeve layer distributed around the circumference of the steel ring body, and the freezing sleeve layer is positioned on the inner side, the outer side or the inner side of the steel ring body; the freezing sleeve layer is provided with at least one freezing part along the axial direction or the circumferential direction, a group of freezing pipelines are arranged in the freezing part, the freezing pipelines are suitable for keeping conveying freezing media, the freezing pipelines are provided with a liquid inlet end and a liquid outlet end, the freezing pipelines are connected with the output end of the freezing unit capable of outputting the freezing media through the liquid inlet end, and the freezing pipelines are connected with the input end of the freezing unit through the liquid outlet end. The invention has high adaptability in water-rich stratum, can freeze the muddy water around the pre-buried steel ring to form stable frozen bodies, and the frozen bodies can block the muddy water in the stratum from leaking into the station, thereby ensuring the safety of the station structure and the ground and having strong adaptability.

Description

Pre-buried steel ring, tunnel portal receiving structure and shield tunnel portal reinforcing method

Technical Field

The invention belongs to the technical field of shield construction, and particularly relates to a pre-buried steel ring, a tunnel portal receiving structure and a shield tunnel portal reinforcing method.

Background

Cities using shields in China are steadily increased, the excavation depth of the central urban area of the extra-large city is deeper, the construction difficulty is higher, and the risk is higher.

In the conventional shield construction at present, two methods are generally adopted to finish the shield receiving when the shield completes the tunnel penetration:

the method comprises the following steps of carrying out reinforcement treatment on the end soil body during the receiving period, wherein the basic requirement of stratum reinforcement is to achieve no water, and the stratum is required to achieve a certain strength requirement, and the stratum treatment method comprises measures such as static pressure grouting, rotary spraying, plain concrete pile, precipitation construction and the like, and is called a stratum reinforcement method receiving shield;

the other method is that the whole tunnel portal is sleeved by a steel sleeve and filled with filler with enough strength, so that the whole shield penetrates through the tunnel portal to reach the steel sleeve during receiving, the tail of the shield leaves the tunnel area, grouting is carried out on gaps between the segments of the tunnel portal area and the pre-buried steel rings of the tunnel portal until the water and soil loss channels in the stratum are completely blocked, the steel sleeve is opened, the shield is removed, and the receiving of the shield is completed.

The two methods ensure that water and soil in the stratum cannot enter a station or the shield during the period that the shield passes through the tunnel portal steel ring, and ensure that the stratum has no water and soil loss. Thereby ensuring the ground safety during shield reception.

At present, aiming at how to seal a gap between a tunnel segment and a portal in the receiving period of a steel sleeve, water and soil outside a station can not enter the station from the gap, and as the burying depth of a tunnel is deeper, the difficulty of sealing the gap in the receiving period of a shield is larger and larger, and the risk is higher and higher.

After the shield tunnel is penetrated, the segment of the shield tunnel and the station structure are connected by reinforced concrete, so that the station and the tunnel structure form a complete whole to solve the problems of tunnel waterproofing and structural stress, the part of the station structure connected with the segment of the tunnel is generally called a flexible structure, and the part is also called a post-pouring ring beam, which is an important connector for connecting the station structure with the tunnel structure.

When the flexible structure is constructed in the past, a large amount of cement paste is injected behind the tunnel segment, part of the tunnel segment can be removed after the cement paste is solidified to reach a certain strength, the cast-in-place structure is formed between the reserved steel ring of the station portal and the tunnel segment, and if the solidification effect of the slurry at the back is poor or uneven, the accident of water and sand burst will occur after the ground water breaks down the part of the slurry.

After the shield starts and the shield tail passes through the pre-buried steel ring of the station structure, the shield cutterhead passes through the starting end reinforcing area of the shield, and the rubber curtain cloth is sealed by the rubber curtain cloth outside the tunnel portal steel ring in the past, so that the bearing pressure is low, the operation is complicated, the grouting pressure is slightly high, the rubber curtain cloth can be damaged, slow grouting is needed, gaps between the pipe pieces and the stratum are filled little by little, and the period of sealing the tunnel portal can be prolonged.

Disclosure of Invention

The invention aims to provide an embedded steel ring with a freezing function, which can freeze water and soil around the embedded steel ring through low-temperature freezing, so that the water and soil can be prevented from entering a station, and further provides a tunnel portal receiving structure, which can freeze the surrounding water and soil when a shield is received through the embedded steel ring, so that the problem that the water and soil flows into the station in the shield receiving process is avoided, and meanwhile, a shield tunnel portal reinforcing method is provided, and the sealing performance of the post-cast beam on the water and soil is improved.

In order to achieve the above purpose, the present invention adopts the following technical scheme:

in a first aspect, an embedded steel ring with a freezing function is provided, and the embedded steel ring comprises a steel ring body, wherein the steel ring body is provided with freezing sleeve layers distributed around the circumference of the steel ring body, and the freezing sleeve layers are positioned at the inner side, the outer side or the inner side of the steel ring body;

the freezing sleeve layer is provided with at least one freezing part along the axial direction or the circumferential direction, a group of freezing pipelines are arranged in the freezing part, the freezing pipelines are suitable for keeping conveying freezing media, the freezing pipelines are provided with a liquid inlet end and a liquid outlet end, the freezing pipelines are connected with the output end of the freezing unit capable of outputting the freezing media through the liquid inlet end, and the freezing pipelines are connected with the input end of the freezing unit through the liquid outlet end.

In a possible implementation, the freezing jacket layer has two freezing sections along its axial direction, the two freezing sections dividing the steel ring body in the axial direction into a first freezing section and a second freezing section, the second freezing section being adjacent to the fixing section of the steel ring body.

In a possible implementation: the freezing medium is calcium chloride brine.

In a possible implementation, the freezing line is provided in the form of an S-shaped disk in the freezing section of the freezing jacket.

In a possible implementation, the freezing sheath is located outside the steel ring body;

the freezing cover layer comprises an annular sealing cover, the annular sealing cover is connected with the outer side face of the steel ring body in a sealing mode, an annular freezing cavity is formed between the annular sealing cover and the outer side face of the steel ring body and is divided into two annular cavity portions along the axial direction, a group of freezing pipelines are arranged in each annular cavity portion, and one annular cavity portion forms a freezing portion.

In a possible implementation, the freezing pipe is welded to the outer side wall of the steel ring body in the annular cavity where it is located.

In a second aspect, a tunnel portal receiving structure is provided, which comprises an embedded steel ring with a freezing function, a steel sleeve matched with the embedded steel ring for receiving, and a counterforce support frame supported on the steel sleeve, wherein the embedded steel ring is arranged on a tunnel portal and has a freezing function according to any one of the technical schemes.

The third aspect provides a shield tunnel portal reinforcing method, based on the pre-buried steel ring with a freezing function, wherein the pre-buried steel ring is provided with a first freezing section and a second freezing section in the axial direction, and the second freezing section is adjacent to a fixed part of a steel ring body, and the method comprises a portal post-pouring beam construction reinforcing method;

the construction and reinforcement method for the post-cast beam of the tunnel portal comprises the following steps:

when the shield completes tunnel construction and passes through the embedded steel ring of the tunnel portal, the shield breaks away from a curtain cloth rubber plate arranged at the outer end of the embedded steel ring, a refrigerating unit is started at the moment, and cement-containing soil among the embedded steel ring, the tunnel segment and the curtain cloth rubber plate is frozen through a first refrigerating section and a second refrigerating section of the embedded steel ring;

removing the tunnel duct piece at the position where the post-pouring beam needs to be poured in the pre-buried steel ring;

stopping the refrigerating medium conveying of the refrigerating unit to the second refrigerating section, and at the moment, freezing the cement-containing soil at the front end of the embedded steel ring, between the tunnel pipe piece and the embedded steel ring through the first refrigerating section in the process of freezing so as to form a blocking object capable of preventing the cement-containing soil from entering the station structure;

and (3) constructing a tunnel portal post-pouring beam, and stopping conveying the freezing medium of the first freezing section by the freezing unit after the post-pouring beam has the designed strength.

In a possible implementation manner, the shield tunnel portal reinforcing method further comprises a shield shell discarding construction portal reinforcing method;

the shield shell discarding construction portal reinforcing method comprises the following steps:

after the shield cutterhead leaves the tunnel portal, starting a refrigerating unit, and enabling the shield shell to form a stable refrigerating body with cement soil between the embedded steel ring and the curtain cloth rubber plate through a first refrigerating section and a second refrigerating section of the pre-embedded steel ring of the tunnel portal so as to block water and soil in the ground from flowing into the station;

injecting grout into the rear of the tunnel segment after the frozen body reaches the required freezing strength, and dismantling the curtain cloth rubber plate of the tunnel portal after the grout strength reaches the requirement;

removing a cutter head of the shield;

welding the front part of the shell of the shield with the inner wall of the embedded steel ring of the tunnel portal to ensure that the shell of the shield and the embedded steel ring of the tunnel portal are connected into a whole;

removing the rest parts except the shell in the shield;

after the disassembly is finished, binding steel bars in the shell of the shield, and pouring concrete to form a reinforced concrete structure, so that the construction is finished.

Compared with the prior art, the invention has the following beneficial effects:

the embedded steel ring with the freezing function has high adaptability in water-rich stratum, can freeze muddy water around the embedded steel ring to form stable frozen bodies, can block muddy water in the stratum from leaking into a station, ensures the safety of the station structure and the ground, and can ensure the safety of operation or construction through freezing in the starting and receiving processes of a shield tunnel and the subsequent tunnel construction, and has strong adaptability.

In addition, in the specific implementation process, the length of the embedded steel ring can be prolonged according to the needs, so that the embedded steel ring can be suitable for freezing water stop in a larger range.

According to the tunnel portal receiving structure, the steel sleeve and the embedded steel ring with the freezing function are matched, so that water and soil outside a station are prevented from entering the station structure through freezing in the shield receiving process, and the safety of shield receiving is improved.

According to the shield tunnel portal reinforcing method, during post-pouring beam construction, due to the fact that part of tunnel segments in the tunnel portal embedded steel ring are removed or cut off, sealing capacity between the embedded steel ring and the tunnel segments is weakened, the risk of water leakage and sand leakage is increased, sealing capacity between the tunnel segments and the embedded steel ring can be guaranteed after freezing through the embedded steel ring with a freezing effect, water and soil outside a station can be effectively prevented from entering a station before the post-pouring beam is not finished, and safety is greatly improved.

Moreover, in the construction process of shell discarding of the shield, when the shell of the shield reaches the inside of the embedded steel ring, the water stopping work can be completed through freezing, and then the shell discarding construction can be carried out more safely, so that the effectiveness and the reliability of water stopping are greatly improved compared with the traditional grouting operation.

Drawings

Fig. 1 is a schematic diagram of an implementation structure of an embedded steel ring with a freezing function according to an embodiment of the present application, where the schematic diagram shows an implementation structure in which a freezing jacket layer is disposed on an inner side of a steel ring body;

FIG. 2 is a schematic diagram of another implementation structure of an embedded steel ring with a freezing function according to an embodiment of the present application, where the schematic diagram shows an implementation structure in which a freezing jacket layer is disposed on the outer side of a steel ring body;

fig. 3 is a schematic structural diagram of a refrigeration pipeline disc of a first refrigeration section and a second refrigeration section in a refrigeration jacket layer of an embedded steel ring with a refrigeration function in an embodiment of the present application;

FIG. 4 is a schematic view of a structure of a portal receiving structure according to an embodiment of the present application;

FIG. 5 is a schematic view of a receiving principle of a portal receiving structure according to an embodiment of the present application;

fig. 6 is a schematic structural diagram of a shield tunnel portal reinforcing method according to an embodiment of the present application when a shield passes through an embedded steel ring during post-cast beam construction and reinforcement;

FIG. 7 is a schematic diagram of a positional relationship between a post-cast beam and an embedded steel ring in the post-cast beam construction reinforcement of a shield tunnel portal reinforcement method according to an embodiment of the present application;

fig. 8 is a schematic diagram of freezing reinforcement of a shield tunnel portal reinforcement method in shield shell discarding construction according to an embodiment of the present application;

fig. 9 is a schematic structural view of an extended pre-buried steel ring with a freezing function according to an embodiment of the present application.

In the figure: 1-embedding a steel ring; 2-a fixing part; 3-freezing the jacket layer; 31-an annular sealing cover; 32-freezing pipeline; 33-freezing chamber; 34-a first freezing section; 35-a second freezing section; 4-steel sleeve; 5-a counterforce support frame; 6-a cord fabric rubber plate; 7-cement-containing soil; 8-tunnel segment; 9-shield; 91-cutterhead; 10-post-pouring the beam; 11-extension.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

The invention is further described with reference to the drawings and specific examples.

Referring to fig. 1-3, an embodiment of the present application provides an embedded steel ring with a freezing function, which includes a steel ring body, wherein the steel ring body is provided with a freezing sleeve layer 3 circumferentially distributed around the steel ring body, and the freezing sleeve layer 3 is located inside, outside or inside the steel ring body. The freezing sleeve layer 3 is a structure which is matched with the steel ring body and is fixed or detachable and used for generating a low-temperature environment capable of freezing surrounding water and soil, and can be understood as a freezing sleeve arranged on the inner side or the outer side of the steel ring body or an interlayer clamped in the steel ring body.

The freezing sleeve layer 3 is provided with at least one freezing part along the axial direction or the circumferential direction, a group of freezing pipelines 32 are arranged in the freezing part, the freezing pipelines 32 are suitable for keeping conveying freezing media, the freezing pipelines 32 are provided with a liquid inlet end and a liquid outlet end, the freezing pipelines 32 are connected with the output end of a freezing unit (not shown in the figure) capable of outputting the freezing media through the liquid inlet end, and the freezing pipelines 32 are connected with the input end of the freezing unit through the liquid outlet end. At least one freezing part of the freezing sleeve layer 3 in the axial direction or the circumferential direction is arranged, and when a plurality of freezing parts are arranged, the sectional freezing or the sectional freezing can be realized, and the configuration can be specifically selected according to the actual requirements. A group of freezing pipelines 32 are arranged in each freezing part, freezing media are arranged in the freezing pipelines 32, a low-temperature environment capable of freezing surrounding water and soil can be conveniently formed through the freezing media, the freezing pipelines 32 are connected with a freezing unit, and the freezing media meeting the freezing temperature requirement can be continuously output through the freezing unit and are circularly conveyed, so that the surrounding water and soil can be continuously and effectively frozen.

The embedded steel ring 1 is an important structural component in the tunnel construction of the shield 9 and the receiving and starting processes of the shield 9, and when the embedded steel ring has the function of freezing surrounding water and soil, better sealing effect can be realized in different construction stages by freezing, so that the operation safety is improved.

Through the technical scheme, the embedded steel ring with the freezing function has high adaptability in the water-rich stratum, muddy water around the embedded steel ring 1 can be frozen to form stable frozen bodies, the frozen bodies can block muddy water in the stratum from leaking into the station, the safety of the station structure and the ground is ensured, and in the starting and receiving processes of the shield 9 tunnel and the follow-up tunnel construction, the safety of operation or construction can be ensured through freezing, so that the adaptability is high.

In one embodiment, the freezing sleeve 3 has two freezing parts along its axial direction, the two freezing parts divide the steel ring body into a first freezing section 34 and a second freezing section 35 in the axial direction, and the second freezing section 35 is adjacent to the fixing part 2 of the steel ring body.

The two freezing parts are axially arranged, so that the steel ring body can be divided into the first freezing section 34 and the second freezing section 35, and the two freezing sections can realize sectional freezing, namely, the two freezing sections can be independently frozen, and then the freezing operation is carried out according to the actual demands, so that the steel ring is more practical.

Further, the freezing medium is calcium chloride brine. The calcium chloride brine can be used as a freezing medium, the freezing point of the calcium chloride brine is lower, and the freezing point of the calcium chloride water can be regulated by controlling the content of calcium chloride, so that the calcium chloride brine can be conveniently regulated according to different freezing demands, is more applicable, and has better freezing effect.

In a specific implementation, as shown in fig. 3, the freezing pipeline 32 is provided in an S-shaped disc in the freezing part of the freezing sleeve layer 3. Such a coiled structure can enable the freezing pipeline 32 to have a longer freezing length in the freezing sleeve layer 3, so that a better freezing effect is achieved.

In order to exemplify the arrangement structure of the freezing jacket 3, the following exemplifies the arrangement structure of the freezing jacket 3 outside the steel ring body:

referring to fig. 2, the freezing jacket layer 3 is located outside the steel ring body; the freezing sleeve layer 3 comprises an annular sealing cover 31, the annular sealing cover 31 is connected with the outer side face of the steel ring body in a sealing mode, an annular freezing cavity 33 is formed between the annular sealing cover 31 and the outer side face of the steel ring body, the freezing cavity 33 is divided into two annular cavity parts along the axial direction, a group of freezing pipelines 32 are arranged in each annular cavity part, and one annular cavity part forms a freezing part.

The annular sealing cover 31 can be matched with the outer side surface of the steel ring body to form an annular sealing space, namely an annular freezing cavity 33, and freezing pipelines 32 are arranged in two annular cavity parts of the annular freezing cavity 33, namely two freezing parts, namely two freezing sections. The structure design is simple, and the normal use of the embedded steel ring 1 is not influenced.

Specifically, the freezing pipeline 32 is welded with the outer side wall of the steel ring body in the annular cavity where the freezing pipeline is located. The freezing pipeline 32 can be more convenient for energy conduction through being welded with the steel ring body, and then can better freeze the surrounding water and soil.

In another embodiment, as shown in fig. 1, the refrigerating jacket layer 3 is located on the inner side of the steel ring body, and its composition structure is substantially the same as that of the case where the outer side is provided.

In a specific implementation process, as shown in fig. 9, when necessary, the freezing steel ring can be extended into the station until the required length is reached, an extension part 11 is formed, and the freezing pipeline of the extended steel ring and the freezing arrangement pipeline of the embedded steel ring are similarly distributed, so that the freezing body length with any required length can be provided on the tunnel axis, the requirement of water stopping capacity can be met, the extended portal steel ring and the embedded steel ring are welded for use, and the outer part of the extended steel ring is exposed in the station, so that the periphery needs to be subjected to heat preservation and isolation treatment.

The extension part of the steel ring can be used as a part of the receiving or starting steel sleeve, can be a part of the embedded steel ring or a part of the starting or receiving steel sleeve, and can be removed after construction is finished.

Referring to fig. 4 and 5, an embodiment of the present application also provides a portal receiving structure, including an embedded steel ring with a freezing function, a steel sleeve 4 matched with the embedded steel ring 1 and received, and a reaction force supporting frame 5 supported on the steel sleeve 4, which are provided in any one of the above technical schemes of the tunnel portal.

Through the cooperation of steel sleeve 4 and pre-buried steel ring that has freezing function, can prevent through freezing that the outside water and soil of station from getting into station structure in shield 9 receiving process, improve shield 9 security of receiving.

In the concrete implementation process, the tunnel portal receiving structure further comprises a curtain cloth rubber plate 6 arranged at the outer end of the embedded steel ring 1, and water and soil can be better prevented from entering the station through the curtain cloth rubber plate 6.

Referring to fig. 6 and 7, an embodiment of the present application further provides a method for reinforcing a tunnel portal of a shield tunnel, based on the pre-buried steel ring with a freezing function in any one of the above embodiments, the pre-buried steel ring 1 has a first freezing section 34 and a second freezing section 35 in an axial direction, and the second freezing section 35 is adjacent to the fixing portion 2 of the steel ring body, including a method for reinforcing a post-cast beam 10 of the tunnel portal.

The construction and reinforcement method for the post-pouring beam 10 of the tunnel portal comprises the following steps:

step S1: when the shield 9 completes tunnel construction and passes through the embedded steel ring 1 of the tunnel portal, the shield 9 is separated from the curtain cloth rubber plate 6 arranged at the outer end of the embedded steel ring 1, a refrigerating unit is started at the moment, and cement-containing soil 7 among the embedded steel ring 1, the tunnel segment 8 and the curtain cloth rubber plate 6 is frozen through a first refrigerating section 34 and a second refrigerating section 35 of the embedded steel ring 1;

step S2: removing the tunnel duct piece 8 at the position where the post-pouring beam 10 needs to be poured in the pre-buried steel ring 1;

step S3: stopping the refrigerating medium conveying of the refrigerating unit to the second refrigerating section 35, and at the moment, freezing the cement-containing soil 7 at the front end of the pre-buried steel ring 1, between the tunnel segment 8 and the pre-buried steel ring 1 through the first refrigerating section 34 in freezing so as to form a plugging material capable of preventing the cement-containing soil 7 from entering the station structure;

step S4: and (3) constructing the tunnel gate post-cast beam 10, and stopping the refrigerating medium conveying of the refrigerating unit to the first refrigerating section 34 after the post-cast beam 10 has the designed strength.

By the construction reinforcing method of the tunnel portal post-cast beam 10, during the construction of the post-cast beam 10, the sealing capability between the pre-cast steel ring 1 and the tunnel pipe piece 8 is weakened due to the fact that part of the tunnel pipe piece 8 in the tunnel portal pre-cast steel ring 1 is removed or cut off, the risk of water leakage and sand leakage is increased, the sealing capability between the tunnel pipe piece 8 and the pre-cast steel ring 1 can be guaranteed after freezing through the pre-cast steel ring 1 with a freezing effect, water and soil outside a station can be effectively prevented from entering the station before the post-cast beam 10 is not finished, and safety is greatly improved.

Further, referring to fig. 8, the method for reinforcing the shield tunnel portal may further include a method for reinforcing the shield 9 shell-discarding construction portal; the shield 9 shell discarding construction portal reinforcing method comprises the following steps:

step S1: after the cutter head 91 of the shield 9 leaves the tunnel portal, a refrigerating unit is started, and the first refrigerating section 34 and the second refrigerating section 35 of the pre-buried steel ring 1 of the tunnel portal enable the housing of the shield 9 to form stable refrigerating bodies with the cement-containing soil 7 between the pre-buried steel ring 1 and the cord fabric rubber plate 6 respectively so as to block the inflow of water and soil in the ground into the station, thus ensuring the safety of the ground.

Before step S1, the steel sleeve 4 and the counter-force frame 5 need to be installed before the shield 9 reaches the receiving area, and the length of the steel sleeve needs to be relatively short, so that the position space for dismantling the cutterhead can be satisfied. Then, the steel sleeve is filled with filler, and step S1 is performed.

Step S2: after the freezing body reaches the required freezing strength, grout is injected into the rear of the tunnel segment 8, and after the grout strength reaches the requirement, the curtain cloth rubber plate 6 of the tunnel portal is removed. When the curtain rubber sheet 6 is removed, the steel sleeve system is also removed.

Step S3: the cutterhead 91 of the shield 9 is removed.

Step S4: and welding the front part of the shell of the shield 9 and the inner wall of the tunnel portal embedded steel ring 1, so that the shell of the shield 9 and the tunnel portal embedded steel ring 1 are connected into a whole.

Step S5: and removing the rest parts except the shell in the shield 9.

Step S6: after the demolition is finished, binding steel bars in the shell of the shield 9, and pouring concrete to form a reinforced concrete structure, so that the construction is finished.

According to the method for reinforcing the shell discarding construction portal of the shield 9, in the shell discarding construction process of the shield 9, when the shell of the shield 9 reaches the inside of the embedded steel ring 1, water stopping work can be completed through freezing, and further shell discarding construction can be carried out more safely, so that the effectiveness and reliability of water stopping are greatly improved compared with the traditional grouting operation.

In other modes, other shield 9 construction operations can be performed by the embedded steel ring with the freezing function, and the method is not limited.

Finally, it should be noted that: the foregoing description is only of the preferred embodiments of the invention and is not intended to limit the scope of the invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (9)

1. The utility model provides an pre-buried steel loop with freezing function, includes the steel loop body, its characterized in that: the steel ring body is provided with freezing sleeve layers (3) distributed around the circumference of the steel ring body, and the freezing sleeve layers (3) are positioned at the inner side, the outer side or the inner side of the steel ring body;

the freezing sleeve layer (3) is provided with at least one freezing part along the axial direction or the circumferential direction, a group of freezing pipelines (32) are arranged in the freezing part, the freezing pipelines (32) are suitable for keeping conveying of a freezing medium, the freezing pipelines (32) are provided with a liquid inlet end and a liquid outlet end, the freezing pipelines (32) are connected with the output end of a freezing unit capable of outputting the freezing medium through the liquid inlet end, and the freezing pipelines (32) are connected with the input end of the freezing unit through the liquid outlet end.

2. The embedded steel ring with a freezing function according to claim 1, wherein: the freezing sleeve layer (3) is provided with two freezing parts along the axial direction of the freezing sleeve layer, the two freezing parts enable the steel ring body to be divided into a first freezing section (34) and a second freezing section (35) in the axial direction, and the second freezing section (35) is adjacent to the fixing part (2) of the steel ring body.

3. The embedded steel ring with a freezing function according to claim 1, wherein: the freezing medium is calcium chloride brine.

4. The embedded steel ring with a freezing function according to claim 1, wherein: the freezing pipeline (32) is arranged in the freezing part of the freezing sleeve layer (3) in an S-shaped disc shape.

5. A pre-buried steel ring with a freezing function according to any one of claims 1 to 4, characterized in that: the freezing sleeve layer (3) is positioned at the outer side of the steel ring body;

the freezing cover layer (3) comprises an annular sealing cover (31), the annular sealing cover (31) is connected with the outer side face of the steel ring body in a sealing mode, an annular freezing cavity (33) is formed between the annular sealing cover (31) and the outer side face of the steel ring body, the freezing cavity (33) is divided into two annular cavity parts along the axial direction, a group of freezing pipelines (32) are arranged in each annular cavity part, and one annular cavity part forms one freezing part.

6. The embedded steel ring with a freezing function according to claim 5, wherein: the freezing pipeline (32) is welded with the outer side wall of the steel ring body in the annular cavity part where the freezing pipeline is positioned.

7. A portal receiving structure, characterized in that: comprising the embedded steel ring with the freezing function, which is arranged on a tunnel portal, as set forth in any one of claims 1-6, a steel sleeve (4) which is matched with the embedded steel ring (1) for receiving, and a counterforce support frame (5) which is supported on the steel sleeve (4).

8. A shield tunnel portal reinforcement method, based on the pre-buried steel ring with freezing function of any one of claims 1-6, the pre-buried steel ring (1) has a first freezing section (34) and a second freezing section (35) in the axial direction, the second freezing section (35) is adjacent to the fixing part (2) of the steel ring body, characterized in that: comprises a construction and reinforcement method of a tunnel portal post-pouring beam (10);

the construction and reinforcement method for the post-cast beam (10) of the tunnel portal comprises the following steps:

when the shield (9) completes tunnel construction and passes through the embedded steel ring (1) of the tunnel portal, the shield (9) is separated from the curtain cloth rubber plate (6) arranged at the outer end of the embedded steel ring (1), a refrigerating unit is started at the moment, and cement-containing soil (7) among the embedded steel ring (1), the tunnel segment (8) and the curtain cloth rubber plate (6) is frozen through a first refrigerating section (34) and a second refrigerating section (35) of the embedded steel ring (1);

removing the tunnel duct piece (8) at the position where the post-pouring beam (10) needs to be poured in the pre-buried steel ring (1);

stopping the refrigerating medium conveying of the refrigerating unit to the second refrigerating section (35), and at the moment, freezing the cement-containing soil (7) between the front end of the embedded steel ring (1), the tunnel segment (8) and the embedded steel ring (1) through the first refrigerating section (34) in freezing so as to form a plugging material capable of preventing the cement-containing soil (7) from entering the station structure;

and (3) constructing the tunnel gate post-pouring beam (10), and stopping conveying the freezing medium of the first freezing section (34) by the freezing unit after the post-pouring beam (10) obtains the design strength.

9. The shield tunnel portal reinforcement method of claim 8, wherein: the shield tunnel portal reinforcing method further comprises a shield (9) shell discarding construction portal reinforcing method;

the shield (9) shell discarding construction portal reinforcing method comprises the following steps:

after a cutter head (91) of the shield (9) leaves a tunnel portal, starting a refrigerating unit, and enabling a housing of the shield (9) to form a stable refrigerating body with cement soil (7) between the pre-buried steel ring (1) and a curtain rubber plate (6) through a first refrigerating section (34) and a second refrigerating section (35) of the pre-buried steel ring (1) of the tunnel portal so as to prevent water and soil in the ground from flowing into a station;

injecting grout into the rear of the tunnel segment (8) after the frozen body reaches the required freezing strength, and dismantling the curtain cloth rubber plate (6) of the tunnel portal after the grout strength reaches the requirement;

removing a cutterhead (91) of the shield (9);

welding the front part of a shell of the shield (9) and the inner wall of the tunnel portal embedded steel ring (1) to ensure that the shell of the shield (9) and the tunnel portal embedded steel ring (1) are connected into a whole;

removing the rest parts except the shell in the shield (9);

after the disassembly is finished, binding steel bars in the shell of the shield (9) and pouring concrete to form a reinforced concrete structure, and finishing the construction.