Steel pipe segment device for freezing soil around tail of shield machine and construction method thereof

Abstract

The present invention discloses a steel pipe segment device for freezing the soil around the tail of a shield machine, comprising: a plurality of arc-shaped steel pipe segments, which are connected in sequence to form an annular steel pipe segment; a freezing pipeline, wherein a plurality of rows of freezing pipelines are arranged along an arc on the inner surface of each arc-shaped steel pipe segment, and the freezing pipelines in the same row on adjacent arc-shaped steel pipe segments are connected through a first pipe to form a plurality of annular freezing pipelines, wherein the refrigerant in the annular freezing pipeline reduces the temperature of the annular steel pipe segment, thereby freezing the soil around it; a rib plate, which is arranged on the inner surface of the arc-shaped steel pipe segment and forms a rib plate cavity, wherein the rib plate cavity is filled with grease with a low freezing point, and an annular thin plate is arranged at the end of the rib plate to block the rib plate cavity to prevent the grease from falling. The device can efficiently freeze the soil around the tail of the shield machine, so that a circle of uniform freezing curtain is formed at the tail of the shield machine, thereby blocking the water and soil outside the gap of the shield tail. The invention also discloses a construction method for replacing the tail brush of the shield machine.

Description

Technical Field

[0001] The present invention relates to the replacement of tail brushes in shield tunnel construction, and more specifically, to a steel pipe segment device for freezing soil around the tail of a shield machine and a construction method thereof. Background Art

[0002] With the acceleration of urbanization, subway tunnel sections are getting longer and longer, and shield tunneling under complex geology is becoming more frequent. Shield tunneling construction in long distances and complex strata has also become an inevitable trend. During the long-distance tunneling of the shield, the shield tail sealing wire brush (hereinafter referred to as "shield tail brush"), one of the main sealing components of the shield machine, is very easy to damage and difficult to repair. There is a certain gap between the outer wall of the shield segment and the inner side of the shield tail. The biggest difficulty in replacement lies in the sealing and water stopping of the shield tail after the segment is removed. Although grouting and water sealing technology has been widely used in the replacement of the shield tail brush, there are objectively unfavorable factors such as the inadaptability of the grouting method stratum, the poor continuity and uniformity of the grouting curtain, and the lack of flexibility and toughness of the bonding between the grouting soil and the shield and the segment, which may lead to the risk of poor water sealing. Especially when it is necessary to replace two tail brushes and the shutdown position is a water-rich unfavorable stratum, the requirements for shield tail water sealing are more stringent.

[0003] Compared with grouting waterstop, the frozen soil curtain formed by the freezing method has the advantages of good continuity, good uniformity, good water sealing and flexibility, and high strength of the frozen body. In the freezing scheme for replacing the tail brush, the conventional freezing method is difficult to implement. It is necessary to design freezing pipes of special form and structure within the low temperature adaptability range of the shield steel and the segment concrete. The conventional practice of drilling holes in the concrete segments at the corresponding positions in the tunnel for freezing has the disadvantages of penetrating damage to the segments, which can lead to permanent leakage risks and poor circumferential uniformity of the frozen soil curtain. In addition, a few domestic projects have adopted built-in freezing pipes in the concrete segments. Due to the sealing of the freezing pipes, once leakage occurs, it cannot be compensated. Summary of the invention

[0004] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.

[0005] Another object of the present invention is to provide a steel pipe segment device for freezing the soil around the tail of a shield machine, which can efficiently freeze the soil around the tail of the shield machine, so that a circle of uniform freezing curtain is formed at the tail of the shield machine, thereby blocking the water and soil outside the gap of the shield tail.

[0006] Another object of the present invention is to improve the efficiency of replacing the tail brush of the shield machine and the reliability and safety of replacing the tail brush, while also simplifying the construction steps.

[0007] In order to achieve these purposes and other advantages of the present invention, a steel segment device for freezing soil around the tail of a shield machine is provided, comprising:

[0008] A plurality of arc-shaped steel pipe segments are connected in sequence to form an annular steel pipe segment;

[0009] A freezing pipeline, wherein multiple rows of freezing pipelines are arranged along an arc line on the inner surface of each arc-shaped steel pipe segment, and the freezing pipelines in the same row on adjacent arc-shaped steel pipe segments are connected by a first pipe to form multiple annular freezing pipelines, and the refrigerant in the annular freezing pipelines reduces the temperature of the annular steel pipe segment, thereby reducing the temperature of the soil around the annular steel pipe segment, so as to freeze the soil around the annular steel pipe segment and form a freezing curtain;

[0010] The rib plate is arranged on the inner surface of the arc-shaped steel pipe segment in a manner perpendicular to the inner surface of the arc-shaped steel pipe segment to form a rib plate cavity. When a plurality of arc-shaped steel pipe segments are connected into an annular steel pipe segment, the rib plate cavity is filled with grease with a low freezing point, and an annular thin plate is arranged at the end of the rib plate to seal the rib plate cavity to prevent the grease from falling.

[0011] Preferably, in the steel pipe segment device for freezing the soil around the tail of the shield machine, each freezing pipeline on each arc-shaped steel pipe segment is respectively provided with a water inlet conduit and a water outlet conduit perpendicular to the end of the freezing pipeline, and the water outlet conduit is connected with the water inlet conduit of the freezing pipeline on the adjacent arc-shaped steel pipe segment through the first tube, and one of the water inlet conduits is used as a coolant circuit, and one of the water outlet conduits is used as a coolant outlet, and is connected to the refrigeration unit.

[0012] Preferably, the steel pipe segment device for freezing the soil around the tail of the shield machine also includes a blind pipe, which is a part of each freezing pipeline on each arc-shaped steel pipe segment after water inlet conduits or water outlet conduits are set at the two ends of each freezing pipeline, and then continue to extend forward to the end of the arc-shaped steel pipe segment to increase the circumferential length of each freezing pipeline.

[0013] Preferably, the steel pipe segment device for freezing the soil around the tail of the shield machine also includes an external freezing pipeline. A groove compatible with the external freezing pipeline is arranged inwardly on the outer surface of the arc-shaped steel pipe segment, and the external freezing pipeline is arranged in the groove. The external freezing pipeline is in direct contact with the surrounding soil to increase the freezing speed of the surrounding soil.

[0014] Preferably, in the steel pipe segment device for freezing the soil around the tail of a shield machine, the freezing pipeline is a U-shaped steel or a circular steel pipe. When the freezing pipeline is a U-shaped steel, the U-shaped steel and the inner surface of the arc-shaped steel pipe segment together form a closed cavity; the outer surface of the arc-shaped steel pipe segment is coated with corrosion-resistant paint.

[0015] Preferably, the steel pipe segment device for freezing the soil around the tail of the shield machine is provided with a temperature measuring hole on each arc-shaped steel pipe segment, and a steel pipe with one end open and the other end closed is radially inserted into the soil through the temperature measuring hole, and a temperature sensor is also provided in the steel pipe to measure the temperature of the soil at different depths.

[0016] Preferably, the steel pipe segment device for freezing the soil around the tail of the shield machine has a temperature measuring cable circumferentially arranged on the front and rear inner surfaces of the annular steel pipe segment along the tunneling direction to determine the freezing range in the axial direction of the tunnel.

[0017] Preferably, the steel pipe segment device for freezing the soil around the tail of the shield machine is provided with a coring hole on each arc-shaped steel pipe segment, a ball valve is installed on the coring hole, and cores are taken through the coring hole during freezing acceptance.

[0018] Preferably, the steel pipe segment device for freezing the soil around the tail of the shield machine is also provided with a shield tail grease pressure relief hole on each arc-shaped steel pipe segment to prevent the grease in the shield tail grease cavity from expanding.

[0019] The object of the present invention can be further achieved by a construction method for replacing a tail brush of a shield machine, the method comprising:

[0020] Step 1: Connect multiple arc-shaped steel pipe segments in sequence to form an annular steel pipe segment;

[0021] Step 2: The outlet pipes and the inlet pipes of the freezing pipelines on the two adjacent arc-shaped steel pipe segments are connected through the first pipe, and one of the outlet pipes is used as a refrigerant outlet and one of the inlet pipes is used as a refrigerant loop to be connected to the refrigeration unit; along the tunnel excavation direction, a temperature measuring cable is annularly arranged on the front and rear inner surfaces of the annular steel pipe segment to determine the freezing range in the tunnel axis direction;

[0022] Step 3: insert a steel pipe with one end open and the other end closed into the soil through the temperature measuring hole in the radial direction, and also set a temperature sensor in the steel pipe to measure the temperature of the soil at different depths;

[0023] Step 4: Fill the rib cavity with grease with a low solidification point, and set an annular thin plate at the end of the rib to seal the rib cavity to prevent the grease from falling;

[0024] Step 5: During freezing acceptance, core the material through the core hole to determine the freezing effect;

[0025] Step 6: When the soil around the tail of the shield reaches the freezing requirement, replace the tail brush of the shield machine. After the construction is completed, backfill cement in the rib cavity as the permanent structure of the tunnel.

[0026] The present invention includes at least the following beneficial effects: since multiple rows of freezing pipelines are arranged along the arc on the inner surface of each arc-shaped steel pipe segment, the freezing pipelines in the same row on adjacent arc-shaped steel pipe segments are connected by a first pipe to form multiple annular freezing pipelines, and the refrigerant in the annular freezing pipelines reduces the temperature of the annular steel pipe segment, thereby reducing the temperature of the soil around the annular steel pipe segment, so as to freeze the soil around the annular steel pipe segment and form an overall annular freezing curtain. The frozen body formed by the annular steel pipe segment ensures the safety of the shield machine when replacing the tail brush of the shield, and also increases the safety of replacing multiple tail brushes or replacing the tail brush in unfavorable strata. In addition, the freezing concept of the annular steel pipe segment does not require freezing of a large range of soil, and its effect on the frost heave and thaw settlement of the soil can be ignored. Ribs are arranged on the inner surface of the curved steel pipe segments to form rib cavities. When multiple curved steel pipe segments are connected into annular steel pipe segments, the rib cavities are filled with grease with a low freezing point. The filling of grease increases the contact area between the refrigeration pipeline and the annular steel pipe segments, thereby improving the refrigeration efficiency. In order to prevent the grease in the rib cavity from falling, an annular thin plate is arranged at the end of the rib for temporary blocking. Due to the high temperature in the tunnel, the setting of the annular thin plate can also reduce the heat convection between the annular steel pipe segments and the air.

[0027] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic structural diagram of a steel pipe segment device for freezing soil around the tail of a shield machine in one embodiment of the present invention;

[0029] Figure 2 It is an AA cross-sectional view of a steel pipe segment device for freezing soil around the tail of a shield machine in another embodiment of the present invention;

[0030] Figure 3 It is an AA cross-sectional view of a steel pipe segment device for freezing soil around the tail of a shield machine in another embodiment of the present invention;

[0031] Figure 4 It is a schematic diagram of the expansion of the arc-shaped steel pipe segment along the tunnel excavation direction in another embodiment of the present invention. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0033] It should be understood that terms such as “having”, “including” and “comprising” used herein do not specify the existence or addition of one or more other elements or combinations thereof.

[0034] like Figures 1 to 4 As shown, the steel pipe segment device for freezing the soil around the tail of a shield machine provided by an embodiment of the present invention comprises: a plurality of arc-shaped steel pipe segments 4, which are sequentially connected to form an annular steel pipe segment 1; a freezing pipeline 2, wherein a plurality of rows of freezing pipelines 2 are arranged along an arc line on the inner surface of each arc-shaped steel pipe segment 4, and the freezing pipelines 2 in the same row on adjacent arc-shaped steel pipe segments 4 are connected by a first pipe 8 to form a plurality of annular freezing pipelines, and the coolant in the annular freezing pipelines reduces the temperature of the annular steel pipe segment 1, thereby The temperature of the soil around the annular steel pipe segment 1 is also reduced to freeze the soil around the annular steel pipe segment 1 to form a freezing curtain 14; the rib 11 is arranged on the inner surface of the arc-shaped steel pipe segment 4 in a manner perpendicular to the inner surface of the arc-shaped steel pipe segment 4, and forms a rib cavity 12. When multiple arc-shaped steel pipe segments 4 are connected to form an annular steel pipe segment 1, the rib cavity 12 is filled with grease with a low freezing point, and an annular thin plate 17 is arranged at the end of the rib 11 to seal the rib cavity to prevent grease from falling.

[0035] In this embodiment, the refrigerant in the multiple annular refrigeration pipelines formed can reduce the temperature of the annular steel pipe segment 1, thereby reducing the temperature of the surrounding soil of the annular steel pipe segment 1, so as to freeze the surrounding soil of the annular steel pipe segment 1, forming an overall annular freezing curtain 14. The impermeable and high-strength freezing curtain 14 can create a good shield tail brush maintenance environment. Therefore, the frozen body formed by the annular steel pipe segment 1 ensures the safety of the shield machine when replacing the shield tail brush 28, and also increases the safety of replacing multiple tail brushes or replacing tail brushes in unfavorable formations. In addition, the freezing concept of the annular steel pipe segment 1 does not require freezing of a large range of soil, and its effect on the frost heave and thaw settlement of the soil can be ignored. Ribs 11 are arranged on the inner surface of the arc-shaped steel pipe segment 4, and a rib cavity 12 is formed. When multiple arc-shaped steel pipe segments 4 are connected to form an annular steel pipe segment 1, the rib cavity 12 is filled with grease with a low freezing point. The filling of grease increases the contact area between the refrigeration pipeline 2 and the annular steel pipe segment 1, thereby improving the refrigeration efficiency. In order to prevent the grease in the rib cavity 12 from falling, an annular thin plate 17 is provided at the end of the rib 11 for temporary blocking. Since the temperature in the tunnel is relatively high, the provision of the annular thin plate can also reduce the heat convection between the annular steel pipe segment 1 and the air.

[0036] It should be noted that the steel pipe segment device must first meet the functions of ordinary concrete pipe segments and be able to resist underground water and soil pressure. The size of the steel pipe segment is designed according to the concrete pipe segment form adopted in the specific project. Through strength verification, a steel pipe segment device formed by arc steel pipe segments 4, freezing pipelines 2, ribs 11, etc. is designed. In addition, the steel pipe segment device has high heat transfer efficiency and can reduce the freezing time. After the final freezing construction is completed, double-fast cement is backfilled in the rib cavity as a permanent structure of the tunnel.

[0037] It should also be noted that the more freezing pipelines 2 are laid along the annular direction, the better the freezing effect of the annular steel pipe segment 1. In the front half of the annular steel pipe segment 1 (the direction of tunnel excavation), it is necessary to set the first three annular freezing pipelines 15. When replacing the tail brush, the heat exchange on the front side of the annular steel pipe segment 1 is relatively intense. These three annular freezing pipelines 15 can effectively isolate and maintain the heat transfer during the freezing period and effectively protect the freezing effect behind. Since each pipeline is independently arranged, the flow rate of the refrigerant in the three annular freezing pipelines can be appropriately increased as needed in actual operation to ensure its insulation effect. In addition, due to the complex construction environment, in order to avoid leakage and damage of the freezing pipeline during freezing, and because the freezing quality at the shield tail position will determine whether the frozen soil curtain can form a rubber ring with the shield tail, the safety significance is of great importance. Therefore, in the specific implementation, this embodiment adds a one-way annular spare freezing pipeline 18 at the exposed shield tail position to improve the reliability of the entire steel pipe segment device to replace the tail brush by the freezing method.

[0038] In another embodiment, if Figure 1 As shown, the steel pipe segment device for freezing the soil around the tail of the shield machine, each end of each freezing pipeline 2 on each arc-shaped steel pipe segment 4 is respectively provided with a water inlet conduit 7 and a water outlet conduit 6 perpendicular to the end of the freezing pipeline, and the water outlet conduit 6 is connected to the water inlet conduit 7 of the freezing pipeline 2 on the adjacent arc-shaped steel pipe segment 4 through the first tube 8, and one of the water inlet conduits is used as a coolant loop 10, and one of the water outlet conduits is used as a coolant outlet 9, and is connected to the refrigeration unit. The provision of the water inlet conduit 7 and the water outlet conduit 6 facilitates the connection of the freezing pipelines 2 on two adjacent arc-shaped steel pipe segments 4. The first tube 8 is preferably a hose.

[0039] In another embodiment, as shown in Figure 1, the steel pipe segment device for freezing the soil around the tail of the shield machine also includes a blind pipe 16, which is a portion of each arc-shaped steel pipe segment 4 that is provided with a water inlet conduit 7 or a water outlet conduit 6 at both ends of each freezing pipeline 2, and then continues to extend forward to the end of the arc-shaped steel pipe segment 4, so as to increase the circumferential length of each freezing pipeline 2. The setting of the blind pipe can ensure that each annular freezing pipeline is continuous on the annular steel pipe segment, eliminate the weak points of the frozen soil curtain 14 caused by the annular discontinuity of the freezing pipeline 2, and further ensure that the freezing curtain formed around the entire annular steel pipe segment is continuous in the annular direction of the annular steel pipe segment.

[0040] In another embodiment, if Figure 2~3As shown, the steel pipe segment device for freezing the soil around the tail of the shield machine also includes an external freezing pipeline 19. A groove 20 adapted to the external freezing pipeline 19 is arranged inwardly on the outer surface of the arc-shaped steel pipe segment 4, and the external freezing pipeline 19 is arranged in the groove 20. The external freezing pipeline 19 is in direct contact with the surrounding soil to increase the freezing speed of the surrounding soil. The external freezing pipeline 19 is set as close as possible to the position where the shield tail is exposed. The specific setting position can be set according to the relative position of the annular steel pipe segment and the shield tail when the tail brush is actually replaced in each engineering project. The external freezing pipeline 19 is in direct contact with the soil, which will greatly improve the freezing effect.

[0041] In another embodiment, if Figure 2~3 As shown, the steel pipe segment device for freezing the soil around the tail of the shield machine, the freezing pipeline is U-shaped steel 3 (reference Figure 3 ) or round steel tube 5 (reference Figure 2 ), when the refrigeration pipeline is U-shaped steel 3, as Figure 3 As shown, the U-shaped steel 3 and the inner surface of the arc-shaped steel pipe segment 4 together form a closed cavity; the outer surface of the arc-shaped steel pipe segment 4 is coated with corrosion-resistant paint 13 to prevent the outer surface from being corroded due to long-term direct contact with the soil. When the refrigeration pipeline 2 uses the U-shaped steel 3, the U-shaped steel 3 is directly welded to the inner surface of the arc-shaped steel pipe segment 4, and the coolant can be in direct contact with the arc-shaped steel pipe segment 4, which can improve the cooling efficiency. The refrigeration pipeline 2 can also use a circular seamless steel pipe 5. Since the contact points with the inner surface of the arc-shaped steel pipe segment 4 are less than that of the U-shaped steel, the cooling efficiency will be slightly reduced.

[0042] In another embodiment, if Figures 2~4 As shown, the steel pipe segment device for freezing the soil around the tail of the shield machine is provided with a temperature measuring hole 21 on each arc-shaped steel pipe segment 4, and a steel pipe 22 with one end open and the other end closed is inserted radially into the soil through the temperature measuring hole 21, and a temperature sensor 23 is also arranged in the steel pipe 22 to measure the temperature of the soil at different depths. Since the entire construction period of replacing the tail brush, from active freezing to maintenance freezing, has a direct guiding significance for the formation and maintenance of the frozen soil curtain and the adjustment of the on-site construction. Therefore, the seamless thin steel pipe 22 with one end open and the other end closed can determine the depth of insertion into the soil according to the thickness of the freezing curtain 14, and the set temperature sensor 23 can monitor the temperature of the soil at different depths along the radial direction, so as to guide the on-site construction.

[0043] In another embodiment, Figure 2~3As shown, the steel pipe segment device for freezing the soil around the tail of the shield machine is provided with a temperature measuring cable 24 on the inner surface of the front and rear ends of the annular steel pipe segment 1 along the tunnel excavation direction to judge the freezing range of the frozen soil curtain 14 in the tunnel axis direction. The provision of the temperature measuring cable 24 can facilitate construction personnel to observe the thickness of the frozen soil curtain and the connection between the frozen wall and the shield tail.

[0044] In another embodiment, if Figure 4 As shown, the steel pipe segment device for freezing the soil around the tail of the shield machine is provided with a core hole 25 on each arc-shaped steel pipe segment 4, and a ball valve is installed on the core hole 25. During the freezing acceptance, the core is taken through the core hole 25 to have a more intuitive evaluation of the freezing effect and ensure the reliability of the construction.

[0045] In another embodiment, if Figure 2 As shown, the steel pipe segment device for freezing the soil around the tail of the shield machine is also provided with a shield tail grease pressure relief hole 26 on each arc-shaped steel pipe segment 4 to prevent the grease in the shield tail grease chamber 27 from expanding. Since the frost heave and thaw sink effect will occur during the freezing period, the grease in the shield tail grease chamber will expand, and the tail brush at the corresponding position may also be damaged in the confined space. Therefore, the shield tail grease pressure relief hole is provided to avoid this situation.

[0046] The embodiment of the present invention is implemented by a construction method for replacing a tail brush of a shield machine, and the method comprises:

[0047] Step 1: Connect multiple arc-shaped steel pipe segments in sequence to form an annular steel pipe segment;

[0048] Step 2: The outlet pipes and the inlet pipes of the freezing pipelines on the two adjacent arc-shaped steel pipe segments are connected through the first pipe, and one of the outlet pipes is used as a refrigerant outlet and one of the inlet pipes is used as a refrigerant loop to be connected to the refrigeration unit; along the tunnel excavation direction, a temperature measuring cable is annularly arranged on the front and rear inner surfaces of the annular steel pipe segment to determine the freezing range in the tunnel axis direction;

[0049] Step 3: insert a steel pipe with one end open and the other end closed into the soil through the temperature measuring hole in the radial direction, and also set a temperature sensor in the steel pipe to measure the temperature of the soil at different depths;

[0050] Step 4: Fill the rib cavity with grease with a low solidification point, and set an annular thin plate at the end of the rib to seal the rib cavity to prevent the grease from falling;

[0051] Step 5: During freezing acceptance, core the material through the core hole to determine the freezing effect;

[0052] Step 6: When the soil around the tail of the shield reaches the freezing requirement, replace the tail brush of the shield machine. After the construction is completed, backfill cement in the rib cavity as the permanent structure of the tunnel.

[0053] As described above, according to the present invention, the steel pipe segment device for freezing the soil around the tail of the shield machine can efficiently freeze the soil around the tail of the shield machine, so that a circle of uniform freezing curtain is formed at the tail of the shield machine, thereby blocking the water and soil outside the gap of the shield tail. The construction method of replacing the tail brush of the shield machine not only improves the efficiency of replacing the tail brush of the shield machine, but also improves the reliability and safety of replacing the tail brush, and also simplifies the construction steps.

[0054] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and the embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily realized. Therefore, without departing from the general concept defined by the claims and equivalent scope, the present invention is not limited to the specific details and the illustrations shown and described here.

Claims

1. A steel pipe segment device for freezing the soil around the tail of a shield machine, characterized in that: include: A plurality of arc-shaped steel pipe segments are connected in sequence to form an annular steel pipe segment; A freezing pipeline, wherein multiple rows of freezing pipelines are arranged along an arc line on the inner surface of each arc-shaped steel pipe segment, and the freezing pipelines in the same row on adjacent arc-shaped steel pipe segments are connected by a first pipe to form multiple annular freezing pipelines, and the refrigerant in the annular freezing pipelines reduces the temperature of the annular steel pipe segment, thereby reducing the temperature of the soil around the annular steel pipe segment, so as to freeze the soil around the annular steel pipe segment and form a freezing curtain; The rib plate is arranged on the inner surface of the curved steel pipe segment in a manner perpendicular to the inner surface of the curved steel pipe segment to form a rib plate cavity. A shield tail grease pressure relief hole is also arranged on each curved steel pipe segment to prevent the grease in the shield tail grease cavity from expanding. When multiple curved steel pipe segments are connected into an annular steel pipe segment, the rib plate cavity is filled with grease with a low freezing point, and an annular thin plate is arranged at the end of the rib plate to seal the rib plate cavity to prevent the grease from falling. When the surrounding soil at the tail of the shield reaches the freezing requirement, the tail brush of the shield machine is replaced. After the construction is completed, cement is backfilled in the rib plate cavity as a permanent structure of the tunnel.

2. The steel pipe segment device for freezing the soil around the tail of a shield machine according to claim 1, characterized in that: Both ends of each refrigeration pipeline on each arc-shaped steel pipe segment are respectively provided with a water inlet pipe and a water outlet pipe perpendicular to the end of the refrigeration pipeline. The water outlet pipe is connected with the water inlet pipe of the refrigeration pipeline on the adjacent arc-shaped steel pipe segment through the first pipe, and one of the water inlet pipes is used as a refrigerant loop, and one of the water outlet pipes is used as a refrigerant outlet, and is connected to the refrigeration unit.

3. The steel pipe segment device for freezing the soil around the tail of a shield machine according to claim 2, characterized in that: It also includes a blind pipe, which is a part of each freezing pipeline on each arc-shaped steel pipe segment that is provided with a water inlet pipe or a water outlet pipe at both ends and continues to extend forward to the end of the arc-shaped steel pipe segment to increase the circumferential length of each freezing pipeline.

4. The steel pipe segment device for freezing soil around the tail of a shield machine according to claim 1, characterized in that: It also includes an external freezing pipeline. A groove matched with the external freezing pipeline is arranged inwardly on the outer surface of the arc-shaped steel pipe segment. The external freezing pipeline is arranged in the groove. The external freezing pipeline is in direct contact with the surrounding soil to increase the freezing speed of the surrounding soil.

5. The steel pipe segment device for freezing the soil around the tail of a shield machine according to claim 1, characterized in that: The refrigeration pipeline is a U-shaped steel or a round steel pipe. When the refrigeration pipeline is a U-shaped steel, the U-shaped steel and the inner surface of the arc-shaped steel pipe segment together form a closed cavity; the outer surface of the arc-shaped steel pipe segment is coated with corrosion-resistant paint.

6. The steel pipe segment device for freezing the soil around the tail of a shield machine according to claim 1, characterized in that: A temperature measuring hole is arranged on each arc-shaped steel pipe segment, and a steel pipe with one end open and the other end closed is inserted radially into the soil through the temperature measuring hole. A temperature sensor is also arranged in the steel pipe to measure the temperature of the soil at different depths.

7. The steel pipe segment device for freezing soil around the tail of a shield machine according to claim 1, characterized in that: Along the tunnel excavation direction, a temperature measuring cable is circumferentially arranged on the inner surface of the front and rear ends of the annular steel pipe segment to determine the freezing range in the tunnel axis direction.

8. The steel pipe segment device for freezing soil around the tail of a shield machine according to claim 1, characterized in that: A core hole is provided on each arc-shaped steel pipe segment, a ball valve is installed on the core hole, and cores are taken through the core hole during freezing acceptance.

9. A construction method for replacing a tail brush of a shield machine, using the steel pipe segment device for freezing the soil around the tail of a shield machine as claimed in any one of claims 1 to 8, characterized in that: The method comprises: Step 1: Connect multiple arc-shaped steel pipe segments in sequence to form an annular steel pipe segment; Step 2: The outlet pipes and the inlet pipes of the freezing pipelines on the two adjacent arc-shaped steel pipe segments are connected through the first pipe, and one of the outlet pipes is used as a refrigerant outlet and one of the inlet pipes is used as a refrigerant loop to be connected to the refrigeration unit; along the tunnel excavation direction, a temperature measuring cable is annularly arranged on the front and rear inner surfaces of the annular steel pipe segment to determine the freezing range in the tunnel axis direction; Step 3: insert a steel pipe with one end open and the other end closed into the soil through the temperature measuring hole in the radial direction, and also set a temperature sensor in the steel pipe to measure the temperature of the soil at different depths; Step 4: Fill the rib cavity with grease with a low solidification point, and set an annular thin plate at the end of the rib to seal the rib cavity to prevent the grease from falling; Step 5: During freezing acceptance, core the material through the core hole to determine the freezing effect; Step 6: When the soil around the tail of the shield reaches the freezing requirement, replace the tail brush of the shield machine. After the construction is completed, backfill cement in the rib cavity as the permanent structure of the tunnel.

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