A method for launching and receiving a shield or pipe jacking construction

Abstract

This invention provides a method for launching and receiving tunnel boring machines (TBMs) or pipe jacking tunnels, comprising: constructing underground retaining structures and underground main structures; installing steel sleeves at the underground retaining structures within the underground main structures, connecting the steel sleeves to the underground main structures, and backfilling soil within the steel sleeves; tunneling the TBM or pipe jacking tunnel and excavating a structural hole in the underground retaining structure, and receiving the TBM into the steel sleeve; freezing the soil around the tunnel segments on the tunnel side to form an annular frozen body, the inner side of the annular frozen body contacting the tunnel segments on the tunnel side, and the side of the annular frozen body closest to the underground retaining structure contacting the underground retaining structure; removing the steel sleeve while maintaining the freeze; completing the portal structure construction at the structural hole while maintaining the freeze; and stopping the freezing. This invention can improve the safety of existing TBM or pipe jacking launching and receiving methods, and eliminates the need for ground reinforcement and dewatering.

Description

Technical Field

[0001] This invention relates to the field of shield tunneling or pipe jacking construction technology, and in particular to a shield tunneling or pipe jacking initiation construction method and a receiving construction method. Background Technology

[0002] With the rapid development of domestic rail transit and river-crossing tunnels, the shield tunneling method is gaining an increasingly important place in tunnel engineering due to its advantages such as high speed, high safety, and minimal impact. During the construction of shield tunnels, the shield launching and arrival phases are high-risk operations. This is especially true in water-rich soft soil and sandy soil strata, which are characterized by high confined water head and high permeability; the successful entry and exit of the shield directly affects the success or failure of the project.

[0003] Currently, the main auxiliary construction methods for shield tunneling in water-rich soft soil strata are soil and water retention, that is, preventing external water and soil from entering the underground structure during the shield machine's entry and exit. The specific methods are mainly divided into the following types: high-pressure jet grouting piles or mixing piles for reinforcement, dewatering (if necessary, U-shaped or mouth-shaped underground continuous walls are set up for assistance), vertical or horizontal freezing, and setting up box-shaped structures or steel sleeves in the station.

[0004] The longitudinal length of high-pressure jet grouting piles or mixing piles in the general tunnel reinforcement area is 6~9m. When the tunnel is buried at a greater depth, the longitudinal length is generally 9~12m (shield machine + 2~3 ring segments). If necessary, U-shaped or U-shaped underground continuous walls can be set. To improve the water sealing effect of the tunnel portal, vertical freezing or horizontal freezing can be set around the tunnel excavation area. To improve the safety of the shield machine before and after arriving at the station, box-type structures or steel sleeves can be set in the station.

[0005] For example, Chinese patent (CN106194218A) describes a soil reinforcement system for the tunnel boring machine (TBM) end in areas with high water head and deep sand layers. This system uses a water-stop curtain made of mixing piles, with the mixing piles used for reinforcement within the curtain. Another Chinese patent (CN111411970A) proposes a method for TBM launch construction under water-rich sandy geological conditions, using a combination of mixing piles and RJP (Rapidly Reinforced Pipe) to reinforce the strata. However, both patents require the installation of surface dewatering wells around the reinforced area and lowering the groundwater level to 1 meter below the tunnel depth before the soil can be effectively absorbed.

[0006] To avoid precipitation, Chinese patent (CN103527214A) describes a method for reinforcing the tunnel entrance and exit ends of a subway shield tunnel using a combination of horizontal freezing and pipe roof reinforcement. This method ensures the safety of the shield tunnel during its entry and exit. The pipe roof primarily protects sensitive structures above the reinforced body. During the tunnel entrance and exit, the shield mainly relies on circumferential horizontal freezing holes for reinforcement and water stoppage. The freezing volume is large and the time is long, and it is not suitable for the entry and exit of slurry balance shield tunnels (the slurry circulation at the tunnel face of a slurry balance shield tunnel affects the temperature of the horizontally frozen body).

[0007] To reduce the volume of frozen material, Chinese patent (CN217129531U) proposes a shield tunneling entry and exit structure that uses a steel sleeve combined with circumferential freezing and water-stopping technology. However, the circumferential freezing pipe has problems such as pipe blockage during diaphragm wall construction and easy damage during shield cutting. This can easily lead to unstable freezing effect, risks of water inrush and mud bursts, and thus low construction safety.

[0008] The current reinforcement schemes and problems at the starting and receiving ends of pipe jacking are similar to those of shield tunneling, and will not be elaborated further.

[0009] Therefore, it is necessary to develop a new method for launching and receiving tunnel boring machines (TBMs) or pipe jacking to improve construction safety. Summary of the Invention

[0010] The purpose of this invention is to provide a method for launching and receiving tunnel boring machines (TBMs) or pipe jacking, so as to improve the safety and applicability of existing methods for launching and receiving TBMs or pipe jacking.

[0011] To solve the above-mentioned technical problems, the present invention provides a shield tunneling or pipe jacking receiving construction method, comprising: constructing an underground retaining structure and an underground main structure; installing a steel sleeve at the underground retaining structure within the underground main structure to connect the steel sleeve to the underground main structure, and backfilling soil inside the steel sleeve; tunneling with a shield tunneling or pipe jacking and excavating a structural hole in the underground retaining structure, and receiving the tunnel segment or pipe section into the steel sleeve; freezing the soil around the tunnel segment or pipe section on the tunnel side to form an annular frozen body, the inner side of the annular frozen body contacting the tunnel segment or pipe section on the tunnel side, and the side of the annular frozen body closest to the underground retaining structure contacting the underground retaining structure; removing the steel sleeve while maintaining the freezing; completing the portal structure construction at the structural hole while maintaining the freezing; and stopping the freezing.

[0012] Optionally, multiple radial freezing pipes can be installed around the tunnel segments or sections, and the radial freezing pipes can be frozen to freeze the soil around the tunnel segments or sections, forming a ring-shaped frozen body.

[0013] Optionally, radial freezing pipes are evenly distributed around the segments or sections of the tunnel and arranged in multiple rows along the tunnel longitudinal direction.

[0014] Optionally, when installing the steel sleeve at the underground retaining structure within the underground main structure, an annular embedded part connecting the underground retaining structure and the steel sleeve is also installed. The annular embedded part is installed on the inner side of the connection between the underground main structure and the steel sleeve.

[0015] Optionally, after the tunnel boring machine or pipe jacking is received into the steel sleeve, the segments or pipe sections inside the steel sleeve include a structural body and an annular cover plate disposed on the outer ring of the segment or pipe section body.

[0016] Optionally, during the removal of the steel sleeve, the gap between the end of the annular embedded part away from the underground retaining structure and the annular cover plate can be sealed with a sealing component.

[0017] Optionally, the sealing element is welded to the annular embedded element and the annular cover plate.

[0018] Optionally, secondary grouting may be performed on the segments or sections before a ring of frozen material is formed around them on the tunnel side.

[0019] Optionally, when constructing underground retaining structures, fiberglass reinforcement may be used to create underground retaining structures where structural openings are required.

[0020] This invention also provides a method for initiating shield tunneling or pipe jacking construction, comprising: constructing underground retaining structures and underground main structures; installing and debugging a shield tunneling machine or pipe jacking machine; installing a steel sleeve at the portal of the underground retaining structure to be excavated within the underground main structure; backfilling soil between the steel sleeve and the shield tunneling machine or between the steel sleeve and the pipe jacking machine; sealing the end of the steel sleeve away from the underground retaining structure; the shield tunneling machine or pipe jacking machine initiating construction from the steel sleeve; the shield tunneling machine or pipe jacking machine excavating and excavating a structural hole in the underground retaining structure, and excavating out the steel sleeve; freezing the soil around the tunnel segments or pipe sections on the tunnel side to form an annular frozen body, the inner side of the annular frozen body contacting the tunnel segments or pipe sections on the tunnel side, and the side of the annular frozen body closer to the underground retaining structure contacting the underground retaining structure; removing the steel sleeve while maintaining the freeze; completing the portal structure construction at the structural hole while maintaining the freeze; and stopping the freezing.

[0021] The present invention provides a method for initiating and receiving tunnel boring machines (TBMs) or pipe jacking, which has the following advantages: The ring-shaped freezing system provides water-stopping protection during the shield tunneling or pipe jacking process. The freezing pipe is less prone to blockage during underground retaining structure construction and damage during shield or pipe jacking reception, resulting in high soil freezing stability and improved construction safety. The ring-shaped freezing system only needs to form a ring around the tunnel segment or section, which, compared to existing technologies requiring large-area horizontal freezing, results in a smaller freezing volume, shorter freezing time, and higher construction efficiency. The steel sleeve is removed and the portal structure is completed while maintaining the freeze, ensuring a reliable water-stopping barrier throughout the entire reception process and avoiding the risks of water inrush and mudslides. No surface dewatering wells are required, avoiding the impact of dewatering construction on the surrounding environment and eliminating the need for large-area cement-based reinforcement, resulting in low construction costs and minimal environmental impact. It has a wide range of applications, suitable for both earth pressure balance shield tunnels and slurry balance shield tunnels, overcoming the limitation of existing horizontal freezing technologies that are unsuitable for slurry balance shield tunnels. Attached Figure Description

[0022] Figure 1 This is a partially enlarged structural diagram of the tunnel portal structure after the shield tunneling or pipe jacking launching and receiving construction method in this embodiment of the invention has completed the construction of the portal structure; Figure 2 This is a partially enlarged structural diagram of the shield tunneling or pipe jacking launching and receiving construction method after the steel sleeve is removed in an embodiment of the present invention; Figure 3 This is a schematic diagram of the arrangement of radial freezing pipes during the construction process of the shield tunneling or pipe jacking initiation and reception method in this embodiment of the invention; Figure 4 This is a schematic diagram of the structure body and the annular cover plate during the construction process of the shield tunneling or pipe jacking initiation and reception construction method in this embodiment of the invention; Figure 5 This is a cross-sectional schematic diagram of a segment or section of a tunnel located within the underground main structure during the construction process of the shield tunneling or pipe jacking launching and receiving method in this embodiment of the invention. Figure 6 This is a schematic diagram showing the connection relationship between the sealing component, the annular embedded component, and the annular cover plate during the construction process of the shield tunneling or pipe jacking initiation and reception method in this embodiment of the invention. Figure 7 This is a schematic diagram of the underground retaining structure and the underground main structure after construction in the shield tunneling or pipe jacking receiving construction method of this invention. Figure 8 This is a schematic diagram of the structure after installing a steel sleeve at the underground retaining structure within the underground main structure in the shield tunneling or pipe jacking receiving construction method of the present invention, connecting the steel sleeve to the underground main structure, and backfilling soil inside the steel sleeve. Figure 9 This is a schematic diagram of the structure after secondary grouting of the tunnel segments or sections in the shield tunneling or pipe jacking receiving construction method of this invention; Figure 10 This is a schematic diagram of the structure after freezing the soil around the tunnel segment or section on the tunnel side to form a ring-shaped frozen body in the shield tunneling or pipe jacking receiving construction method of this invention. Figure 11 This is a schematic diagram of the structure after the steel sleeve is removed in the shield tunneling or pipe jacking receiving construction method of this invention; Figure 12 This is a schematic diagram of the structure of the tunnel portal structure at the structural opening in the shield tunneling or pipe jacking receiving construction method of the present invention. Figure 13 This is a schematic diagram of the structure after freezing the soil around the tunnel segments or sections on the tunnel side to form a ring-shaped frozen body in the shield tunneling or pipe jacking starting construction method of this invention.

[0023] Explanation of reference numerals in the attached figures: 110 - Underground retaining structure; 111 - Fiberglass reinforcement; 120 - Underground main structure; 130 - Annular frozen body; 140 - Segment or section; 141 - Structural body; 142 - Annular cover plate; 150 - Steel sleeve; 160 - Portal structure; 170 - Radial frozen pipe; 180 - Annular embedded part; 190 - Sealing part; 200 - Secondary grouting layer; 210 - Tunnel; 220 - Tunnel boring machine or pipe jacking machine; 230 - Backfill soil. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but these embodiments should not be construed as limiting the present invention.

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but these embodiments should not be construed as limiting the present invention.

[0026] refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 and Figure 12 , Figure 1 This is a partially enlarged structural diagram of the tunnel portal structure after the shield tunneling or pipe jacking receiving construction method in this embodiment of the invention has completed the construction of the portal structure. Figure 2 This is a partially enlarged structural diagram of the shield tunneling or pipe jacking receiving and transmitting method after the steel sleeve has been removed, according to an embodiment of the present invention. Figure 3 This is a schematic diagram of the arrangement of radial freezing pipes during the construction process of the shield tunneling or pipe jacking receiving method in this embodiment of the invention. Figure 4 This is a schematic diagram of the structure body and the annular cover plate during the construction process of the shield tunneling or pipe jacking receiving construction method in this embodiment of the invention. Figure 5 This is a schematic cross-sectional view of a segment or section of the tunnel boring machine (TBM) or pipe jacking receiving method located within the underground main structure during the construction process, as described in this embodiment of the invention. Figure 6 This is a schematic diagram illustrating the connection relationship between the sealing component, the annular embedded component, and the annular cover plate during the construction process of the shield tunneling or pipe jacking receiving method in this embodiment of the invention. Figure 7 This is a schematic diagram of the underground retaining structure and underground main structure after construction in the shield tunneling or pipe jacking receiving and launching construction method of this invention. Figure 8 This is a schematic diagram of the structure after installing a steel sleeve at the underground retaining structure within the underground main structure in the shield tunneling or pipe jacking receiving construction method of this invention, connecting the steel sleeve to the underground main structure, and backfilling soil inside the steel sleeve. Figure 9 This is a schematic diagram of the structure after secondary grouting of tunnel segments or sections in the shield tunneling or pipe jacking receiving construction method of this invention. Figure 10 This is a schematic diagram of the structure after freezing the soil around the tunnel segments or sections on the tunnel side to form a ring-shaped frozen body in the shield tunneling or pipe jacking receiving construction method of this invention. Figure 11 This is a schematic diagram of the structure after the steel sleeve is removed in the shield tunneling or pipe jacking receiving construction method of this invention. Figure 12 This is a structural diagram illustrating the construction of the portal structure at the structural opening in the shield tunneling or pipe jacking receiving construction method of this invention. This embodiment provides a shield tunneling or pipe jacking receiving construction method, including: Step S100: Construction of underground retaining structure 110 and underground main structure 120. Step S200: Install a steel sleeve 150 at the underground retaining structure 110 within the underground main structure 120 to connect the steel sleeve 150 with the underground main structure 120, and backfill the steel sleeve 150 with soil 230. In step S300, the shield tunnel or pipe jacking 220 tunnels and excavates a structural hole on the underground retaining structure 110, and receives the tunnel into the steel sleeve 150. Step S400: Freeze the soil around the tunnel segment or section 140 on the side of tunnel 210 to form an annular frozen body 130. The inner side of the annular frozen body 130 is in contact with the tunnel segment or section 140 on the side of tunnel 210, and the side of the annular frozen body 130 closest to the underground retaining structure 110 is in contact with the underground retaining structure 110. Step S500: While maintaining the freeze, remove the steel sleeve 150; Step S600: While maintaining the frozen condition, complete the construction of the portal structure 160 at the structural opening; Step S700: Stop freezing.

[0027] The installation of the steel sleeve 150 and the backfill soil 230 provide a safe and sealed transition space for the receiving of the tunnel boring machine (TBM) or pipe jacking machine 220. The formation of the annular frozen body 130, a crucial water-stopping measure completed before the removal of the steel sleeve 150, is in contact with both the tunnel segments or sections 140 and the underground retaining structure 110, forming a complete annular water-stopping barrier. Removing the steel sleeve 150 while maintaining the frozen condition and completing the portal structure 160 ensures reliable water-stopping protection throughout the final stage of the entire receiving process. This entire method, through the dual protection of the steel sleeve 150 and the annular frozen body 130, achieves the safe receiving of the TBM or pipe jacking machine 220 in water-rich soft soil strata.

[0028] In this embodiment, the annular freezing body 130 achieves water-stopping protection during the shield or jacking pipe 220 receiving process. The freezing pipe is less prone to blockage during the construction of the underground retaining structure 110 and less likely to be damaged during the shield or jacking pipe 220 receiving process. Therefore, the soil freezing stability is high, thereby improving construction safety. The annular freezing body 130 only needs to form an annular freeze around the segment or section 140. Compared to the existing technology that requires large-area horizontal freezing, the freezing volume is small, the freezing time is short, and the construction efficiency is high. While maintaining the freeze, the steel sleeve 150 is removed and the portal structure 160 is constructed, ensuring a reliable water-stopping barrier throughout the receiving process and avoiding the risks of water inrush and mudslides. No ground dewatering wells are required, avoiding the impact of dewatering construction on the surrounding environment. Large-area cement-based reinforcement is also unnecessary, resulting in low construction costs and minimal environmental impact. It has a wide range of applications, suitable for both earth pressure balance shields and slurry balance shields, overcoming the limitation of existing horizontal freezing technologies that are not suitable for slurry balance shields.

[0029] When constructing the underground retaining structure 110, the underground retaining structure 110 is made of glass fiber reinforced concrete 111 where structural openings are required.

[0030] Fiberglass reinforced concrete (FRP) 111 is a type of reinforcing bar made from glass fiber reinforced composite materials. When constructing the reinforcing cage for underground retaining structures (such as diaphragm walls), FRP 111 replaces traditional steel bars at locations where structural openings are required. FRP 111 is machinable; the cutterhead of a tunnel boring machine (TBM) or pipe jacking machine (TBM 220) can directly cut into the underground retaining structure 110 made of FRP 111 during excavation without pre-excavating the opening. FRP 111 has good bonding properties with concrete, meeting the load-bearing requirements of the underground retaining structure 110.

[0031] Fiberglass reinforcement 111 is machinable, allowing shield tunneling or pipe jacking 220 to directly cut and excavate without pre-removing the tunnel portal. This eliminates the portal removal process, shortens the construction cycle, and improves construction efficiency. It also avoids potential safety and environmental problems (such as noise and dust) that may arise during portal removal. Fiberglass reinforcement 111 has excellent corrosion resistance and a long service life. The application of fiberglass reinforcement 111 simplifies the construction of the underground retaining structure 110 and saves on steel reinforcement materials.

[0032] In this embodiment, the underground retaining structure 110 is preferably a diaphragm wall. The construction requirements for the diaphragm wall are as follows: 1. In water-rich soft soil strata, diaphragm walls are often used as retaining and water-blocking structures in underground engineering projects due to their high rigidity and good water-stopping effect.

[0033] 2. To facilitate direct cutting of the diaphragm wall by the tunnel boring machine (TBM), the reinforcing steel bars of the diaphragm wall in the area surrounding the TBM's entry and exit points must be replaced with fiberglass reinforced plastic (FRP) bars. The reinforcing steel bars and FRP bars are connected and fixed using U-shaped locking mechanisms. When the TBM cuts the FRP diaphragm wall, it can advance slowly by increasing the TBM torque and reducing the cutterhead speed.

[0034] By setting multiple radial freezing pipes 170 around the segments or sections 140 on the side of tunnel 210 and freezing the radial freezing pipes 170, the soil around the segments or sections 140 on the side of tunnel 210 is frozen in step S400 to form an annular frozen body 130.

[0035] The installation of radial freezing pipes 170 is simple and flexible, and the number and arrangement of radial freezing pipes 170 can be adjusted according to actual geological conditions and construction needs. Arranged radially, the radial freezing pipes 170 eliminate the problem of pipe blockage during diaphragm wall construction compared to circumferential horizontal freezing pipes, resulting in a stable and reliable freezing effect. The radial freezing pipes 170 are installed around the pipe segments or sections 140, without passing through the underground retaining structure 110, thus avoiding the risk of damage to the freezing pipes during shield tunneling or pipe jacking 220 cutting.

[0036] Furthermore, the radial freezing pipes 170 are evenly distributed around the pipe segments or sections 140, and are arranged in multiple rows longitudinally in the tunnel 210.

[0037] Radial freezing pipes 170 are evenly distributed circumferentially around the pipe segments or sections 140, ensuring the uniformity and continuity of the frozen body in the circumferential direction. Multiple rows of radial freezing pipes 170 are arranged longitudinally along the tunnel 210, ensuring sufficient thickness of the frozen body in the longitudinal direction. This multi-row arrangement allows the freezing areas formed by each row of radial freezing pipes 170 to overlap longitudinally, forming an annular frozen body 130 with sufficient longitudinal thickness, thus ensuring the reliability of the water-stopping effect.

[0038] The even distribution of radial freezing pipes 170 ensures the integrity and uniformity of the annular freezing body 130 in the circumferential direction, avoiding weak areas in the water-stopping mechanism caused by uneven freezing. The multi-row arrangement gives the annular freezing body 130 sufficient longitudinal thickness, improving the overall strength and water-stopping effect. The multi-row arrangement allows for flexible adjustment of the number and spacing of rows according to actual needs, adapting to different geological conditions and water head pressures. The multiple rows of radial freezing pipes 170 allow for batch and area-by-area freezing operations, enabling flexible construction organization.

[0039] In this embodiment, the freezing technology requirements are as follows: 1. For various models of tunnel boring machines (TBMs) both domestically and internationally, the dimensions are generally: cutterhead excavation diameter > TBM main unit > 140mm tunnel segment. Taking a certain model of TBM as an example, for a 140mm tunnel segment with an outer diameter of 6000mm, the cutterhead excavation diameter is 6320mm, and the main unit diameter is 6250mm. After excavation, there is a 70mm gap between the excavation face and the main unit, and a 320mm gap between the excavation face and the 140mm tunnel segment. This gap easily becomes a channel for external water and soil to flow into the underground structure, and the larger the excavation diameter, the larger this gap becomes.

[0040] 2. To seal this passage, secondary grouting using the shield tunnel is commonly employed. However, when the shield tunneling depth or diameter is large, this method may not guarantee that the gaps will be filled. To ensure the gaps are filled, multiple secondary grouting operations are required after the shield segment 140 is assembled, ensuring that the gaps between the segment or section 140 and the excavation face are densely filled. In actual engineering projects, to prevent water and sand inflow into the passage, surface dewatering, surface mixing piles, or high-pressure jet grouting are often used to ensure construction safety.

[0041] 3. Methods for freezing soil include brine freezing and liquid nitrogen freezing.

[0042] Brine freezing is an artificial forced circulation brine freezing technology that removes heat from the soil by establishing a brine circulation system. Brine freezing requires a large site area (because a freezing circulation system needs to be established), and the freezing process takes a long time (generally 45-60 days). However, the engineering cost is lower than that of liquid nitrogen freezing, making it widely used.

[0043] Liquid nitrogen freezing is an artificial soil freezing technology that relies on the rapid vaporization of liquid nitrogen within a freezing pipe to directly absorb heat, thereby reducing the heat in the surrounding soil and achieving rapid freezing. Liquid nitrogen freezing systems are simple in structure and require little site space (cryogenic liquid nitrogen can be supplied directly from the ground by liquid nitrogen tankers), and the freezing time is short (generally 1 / 3 to 1 / 2 of that of brine freezing). However, the engineering cost is relatively high, and it is frequently used in emergency rescue and other similar projects.

[0044] The gap between the tunnel boring machine (TBM) excavation face and the TBM segments or sections 140 is small near the tunnel entrance and needs to be quickly sealed when the TBM is received, so liquid nitrogen freezing is required; at the start of the TBM launch, due to the long tunneling time, brine freezing can be used.

[0045] 4. Radial freezing pipes 170 are arranged in the completed shield tunnel 210. The ring shield segment or section 140 adopts a special design. There are 6 segments or sections 140 in the ring. The segment or section 140 has 16 freezing holes in the radial direction and 2 rows of freezing holes in the longitudinal direction.

[0046] The length of the radial freezing holes can be adjusted according to the geological and hydrological conditions of each project. For example, if the strata around the lower half of the tunnel section 210 have high impermeability, the length of the radial freezing holes can be shortened or the radial freezing holes in the lower half of the section can be eliminated.

[0047] The freezing process uses either brine freezing or liquid nitrogen freezing, and the specific technical parameters are as follows: Brine freezing tubing: φ89mm 4mm stainless steel seamless pipes are used to connect the various freezing pipes to the inlet and outlet pipelines. The freezing station is located inside the working shaft. During freezing, the temperature difference between the outgoing and return brine is less than 2℃, and the average temperature at the interface between the solidified material and the tunnel segment or section 140 is less than -5℃. All exposed freezing pipes and the inner arc surface of the shield tunnel segment are insulated with thermal insulation foam boards.

[0048] Liquid nitrogen freezing tube: φ89mm 4mm seamless stainless steel pipes are used for connection, with each freezing pipe connected to a distributor for distribution to each pipe. During freezing, a single-hole, single-circulation method is used to ensure uniform outward temperature diffusion from the radial freezing pipes at 170°. All exposed freezing pipes and the inner arc surface of the tunnel segments are insulated with thermal foam boards.

[0049] After completion, the radial freezing holes form an annular frozen body 130 around the soil between the pipe segment or section 140 and the retaining structure, so as to seal the longitudinal leakage channels of the pipe segment or section 140.

[0050] To ensure the sealing effect, the frozen and reinforced soil must have good sealing properties and necessary strength. The freezing ratio functional category should meet the requirements of Class I frozen wall (only used for water stoppage and without load bearing). In soft soil strata, the design thickness of the horizontal frozen wall should not be less than 2.0m, and the specific thickness can be adjusted according to the geological and hydrological conditions around Tunnel 210.

[0051] In step S200, when the steel sleeve 150 is installed at the underground retaining structure 110 within the underground main structure 120, an annular embedded part 180 connecting the underground retaining structure 110 and the steel sleeve 150 is also installed. The annular embedded part 180 is installed on the inner side of the connection between the underground main structure 120 and the steel sleeve 150.

[0052] The annular embedded part 180 is a ring-shaped steel component pre-embedded during the construction of the underground main structure 120. One side of the annular embedded part 180 is fixedly connected to the underground main structure 120 (connected to the main reinforcing bars of the main structure via connecting bars and cast integrally), and the other side is used to connect to the steel sleeve 150. The annular embedded part 180 is installed on the inner side of the connection between the underground main structure 120 and the steel sleeve 150, so that the steel sleeve 150 can be reliably connected to the underground main structure 120 through the annular embedded part 180. The annular embedded part 180 also serves as a sealing interface between the steel sleeve 150 and the underground main structure 120, preventing external water and soil from seeping in from the connection.

[0053] The annular embedded part 180 provides a reliable connection foundation for the steel sleeve 150, ensuring the stability and sealing of the steel sleeve 150 installation. The annular embedded part 180 is integrally cast with the underground main structure 120, resulting in high connection strength, minimal deformation, and good flatness. As a sealing interface, the annular embedded part 180 effectively prevents external water and soil from seeping in at the connection between the steel sleeve 150 and the underground main structure 120. The annular embedded part 180 also facilitates the installation and removal of the steel sleeve 150, improving construction efficiency.

[0054] In step S300, after the shield is received into the steel sleeve 150, the segment or section 140 inside the steel sleeve 150 includes the segment or section body 141 and the annular cover plate 142 disposed on the outer ring of the structure body 141.

[0055] The segment or section 140 is the tunnel lining structure 210 assembled during the tunnel boring machine (TBM) or pipe jacking machine (TBM) 220 excavation. After receiving, in addition to the conventional structural body 141, the segment or section 140 inside the steel sleeve 150 also has an annular cover plate 142 installed on the outer ring of the structural body 141. The annular cover plate 142 is a ring-shaped steel plate fixed to the outer arc surface of the structural body 141. The installation of the annular cover plate 142 makes the outer ring of the segment or section 140 form a continuous steel surface, providing a flat and reliable welding connection surface for subsequent sealing operations.

[0056] The annular cover plate 142 provides an additional steel protective layer for the tunnel segment or section 140, enhancing its structural strength. The annular cover plate 142 forms a continuous steel surface, providing a reliable welded connection surface for sealing the gap between the annular embedded part 180 and the tunnel segment or section 140. The annular cover plate 142 is tightly integrated with the structural body 141, improving the flatness and sealing performance of the outer surface of the tunnel segment or section 140. The installation of the annular cover plate 142 makes the sealing operation simpler and more reliable, improving the quality and efficiency of portal sealing.

[0057] Preferably, the annular cover plate 142 is a steel plate.

[0058] The annular cladding plate 142 is made of steel plate, utilizing the high strength, good weldability, and machinability of steel. The steel plate can be processed according to the outer arc shape of the pipe segment or section 140, and tightly fitted onto the outer ring of the structural body 141. As an annular cladding plate 142, the steel plate provides sufficient structural strength and a good welding interface for subsequent welding and sealing operations.

[0059] The steel plate boasts high strength and rigidity, effectively protecting the structural body 141 and enhancing the overall structural performance of the segments or sections 140. Its excellent weldability facilitates welding connections with the sealing component 190, ensuring reliable sealing. Furthermore, the steel plate exhibits good machinability, allowing for precise processing according to the actual shape of the segments or sections 140 to ensure a tight fit. Finally, the steel plate is widely available and moderately priced, offering excellent economic benefits.

[0060] In step S500, during the removal of the steel sleeve 150, the gap between the end of the annular embedded part 180 away from the underground retaining structure 110 and the annular cover plate 142 is sealed by the sealing part 190.

[0061] After the steel sleeve 150 is removed, an annular gap exists between the annular embedded part 180 and the segment or section 140 (annular cover plate 142). This gap is a potential channel for external water and soil to seep into the underground main structure 120. A sealing member 190 is used to seal the gap between the end of the annular embedded part 180 away from the underground retaining structure 110 and the annular cover plate 142. One side of the sealing member 190 is connected to the annular embedded part 180, and the other side is connected to the annular cover plate 142, completely sealing the gap between them. The sealing member 190 is installed gradually during the removal of the steel sleeve 150 to ensure a reliable seal at any stage of the steel sleeve 150 removal process.

[0062] The sealing element 190 seals the gap between the annular embedded part 180 and the annular cover plate 142, effectively blocking the seepage channel of external water and soil. The sealing operation is carried out while maintaining a frozen state; even if a temporary seal failure occurs during the sealing process, the frozen body provides water-stopping protection, offering double protection for construction safety. The installation of the sealing element 190 makes the seal at the tunnel portal more complete and reliable, creating favorable conditions for the subsequent construction of the tunnel portal structure 160. The sealing element 190 can be welded to the annular embedded part 180 and the annular cover plate 142 to form a permanent sealing structure.

[0063] Preferably, the sealing element 190 is a steel plate.

[0064] The sealing component 190 is made of steel plate, utilizing the high strength, good weldability, and machinability of steel. The steel plate can be machined according to the actual shape and size of the gap between the annular embedded part 180 and the annular cover plate 142. As the sealing component 190, the steel plate provides sufficient structural strength and can be reliably welded to the annular embedded part 180 and the annular cover plate 142 to form a complete sealing structure.

[0065] The steel plate, used as the sealing component 190, possesses high strength and rigidity, enabling it to withstand external water and soil pressure and ensuring reliable sealing. The steel plate exhibits good weldability, allowing for reliable welding with the annular embedded component 180 and the annular cover plate 142 to form a permanent sealing structure. The steel plate is flexible in processing and can be customized according to the actual gap shape, offering strong adaptability. Furthermore, the steel plate is widely available and moderately priced, resulting in good economic efficiency.

[0066] Preferably, the sealing component 190 is welded to the annular pre-embedded component 180 and the annular cover plate 142.

[0067] The sealing component 190 (steel plate) is connected to the annular embedded component 180 and the annular cover plate 142 by welding. Welding creates a complete steel integral structure with the sealing component 190, the annular embedded component 180, and the annular cover plate 142, resulting in high connection strength and good sealing performance. Welding methods include fillet welds and butt welds, with the appropriate method selected based on the actual structural form and stress requirements. After welding, a continuous metal connection is formed between the sealing component 190, the annular embedded component 180, and the annular cover plate 142, completely sealing the gap.

[0068] The welded connection boasts high strength, reliably withstanding external water and soil pressure, ensuring long-term reliability of the seal. The welded connection is a continuous metal joint with excellent sealing performance, effectively preventing water and soil leakage. Welding operations are simple and efficient, enabling rapid completion of the sealing work. The welded connection is permanent and compatible with subsequent portal structure construction, requiring no additional dismantling.

[0069] In step S500, during the process of removing the steel sleeve 150, the steel sleeve 150 is removed piece by piece from top to bottom, and after each piece of steel sleeve 150 is removed, the gap between the annular embedded part 180 and the annular cover plate 142 at the corresponding position is sealed with the sealing part 190.

[0070] The steel sleeve 150 is typically assembled from multiple steel plates. When dismantling the steel sleeve 150, it is removed piece by piece from top to bottom. Each time a steel sleeve 150 is removed, the gap between the annular embedded part 180 and the annular cover plate 142 covered by that steel sleeve 150 is exposed. At this point, the gap is immediately sealed with a sealing component 190. This piece-by-piece removal and sealing method ensures that throughout the entire dismantling process, the sealing component 190 or any remaining steel sleeves 150 provide a continuous seal, preventing large areas of gaps from being exposed simultaneously.

[0071] The top-down, piece-by-piece dismantling method utilizes gravity, making the dismantling operation safer and more efficient. Each dismantled piece is immediately sealed, ensuring a sealed state throughout the entire dismantling process and avoiding the risks of water inrush or mud surge. This piece-by-piece dismantling and sealing approach ensures orderly construction and controllable sealing quality. Even if a sealing problem occurs in one piece, the overall seal will not fail because the steel sleeves in other locations have not yet been removed or are already sealed, resulting in high construction safety.

[0072] In step S600, the construction of the portal structure 160 at the structural opening includes setting an external portal at the contact point between the underground main structure 120 and the segment or section 140 and the sealing member 190.

[0073] The construction of the portal structure 160 is a permanent structural construction carried out after the removal and sealing of the steel sleeve 150. An external portal is installed between the underground main structure 120 and the tunnel segment or section 140, at the contact point with the sealing element 190. The external portal is an additional reinforced concrete structure poured outside the sealing element 190, enclosing the sealing element 190 within it. As a reinforcing layer of the portal structure 160, the external portal, together with the sealing element 190, constitutes the complete portal structure 160, permanently connecting the station structure (underground main structure 120) and the tunnel 210 structure (tunnel segment or section 140).

[0074] The outer portal, acting as a reinforcing layer of the portal structure 160, enhances the structural strength and integrity of the portal area. It encloses the sealing element 190, protecting it and improving the long-term reliability of the seal. The outer portal forms a reliable connection with the underground main structure 120 and the tunnel segments or sections 140, integrating the station structure with the tunnel 210 structure into a complete whole. The outer portal possesses excellent waterproofing performance, meeting the waterproofing and structural load-bearing requirements of the tunnel 210.

[0075] Between steps S300 and S400, before forming an annular frozen body 130 around the segment or section 140 on the tunnel 210 side, secondary grouting is performed on the segment or section 140 to form a secondary grouting layer 200.

[0076] Secondary grouting is a grouting operation performed after the tunnel boring machine (TBM) or pipe jacking 220 has been excavated and before the formation of the annular frozen body 130. Cement grout or other grout is injected into the back of the segment or section 140 through grouting holes on the segment or section 140 to fill the voids between the segment or section 140 and the ground, improving the density and waterproofing performance behind the segment or section 140. Secondary grouting also improves the physical and mechanical properties of the ground surrounding the segment or section 140, creating favorable conditions for subsequent freezing construction.

[0077] Secondary grouting fills the voids between the tunnel segment or section 140 and the ground, increasing the density behind the segment or section 140. Secondary grouting improves the physical and mechanical properties of the ground surrounding the segment or section 140, increasing its thermal conductivity and improving the efficiency of the freezing construction. Secondary grouting enhances the waterproofing behind the segment or section 140, reducing groundwater flow behind it and facilitating the formation and maintenance of the annular frozen body 130. Secondary grouting provides better construction conditions for the annular frozen body 130, ensuring its quality and effectiveness.

[0078] Secondary grouting has the following characteristics: Grouting inside the tunnel is carried out after the shield tunneling machine and its supporting equipment have completely passed through the clearing tunnel 210. The secondary grouting holes utilize the 16 grouting holes on the existing segments or sections 140. Before opening the hole, an anti-gushing device is installed at the opening point to ensure safety during the opening process.

[0079] Secondary grouting parameters: 1. The grouting pressure is determined based on the field test results, and is generally controlled at around 0.5 MPa; the grouting material is single-component grout or double-component grout, and the grouting range should cover the entire frozen area.

[0080] 2. Following the principle of "multiple points, small amounts, multiple times, and uniformity", the actual grouting volume for each injection can be appropriately adjusted based on feedback from ground settlement monitoring and temperature field monitoring.

[0081] 3. When the stratum settlement is greater than 0.5 mm / d or the cumulative settlement is greater than 3 mm, grouting for settlement compensation should be carried out. Grouting should be suspended when the stratum uplift reaches 3 mm.

[0082] 4. Grouting can only be stopped when the frozen wall has completely thawed, and the measured stratum deformation has remained below 0.5 mm / 15d for a month and twice is less than 0.5 mm / 15d, indicating that the deformation is basically stable.

[0083] The segment or section 140 in this embodiment has the following characteristics: During shield tunneling reception, the planar position of the tunnel segment or section 140 near the tunnel portal can be calculated or predicted in advance. To facilitate rapid welding and sealing during the later removal of the steel sleeve 150, the back of the tunnel segment or section 140 near the tunnel portal is constructed with an annular cover plate 142. The annular cover plate 142 is pre-embedded and installed during the fabrication of the tunnel segment or section 140, with the anchor bars welded to the back cover plate on one side, and the weld height is 8mm. After the shield tunneling in the section is completed, during the launching or receiving phase, under the protection of frozen water stop, the steel sleeve 150 is cut and removed piece by piece from top to bottom. The tunnel portal ring is then firmly welded to the back cover plate of the tunnel segment or section 140 using a 10mm sealing piece 190, thereby further effectively preventing water and soil from entering the working shaft from the tunnel segment or section 140. The weld must be continuous and leak-free.

[0084] Steel sleeve 150 has the following characteristics: The dimensions of the 150mm steel sleeve need to be determined based on construction requirements and the dimensions of the tunnel boring machine (TBM). Taking a certain model of TBM as an example, with a 140mm TBM segment and an outer diameter of 6000mm, the TBM itself is 9500mm long. Therefore, the 150mm steel sleeve's cylindrical section is 10500mm long and has an inner diameter of 6800mm. It is divided into four sections, each further divided into upper and lower parts. The cylindrical section is made of 16mm thick Q235A steel plate. Each section has longitudinal and circumferential stiffening ribs welded to its outer perimeter to form a mesh to ensure the rigidity of the cylindrical section. The stiffening ribs are 20mm thick, 150mm high, and spaced approximately 550mm apart. 600mm; flanges are welded to the ends of each section of the cylinder and the arc joint surfaces of the upper and lower sections. The flanges are made of 24mm thick Q235A steel. The connection between the upper and lower sections and between the two cylinder sections are made of 8.8 grade M30 steel. 90mm bolts are used for connection, with a 3mm thick rubber gasket in the middle to ensure a good seal. The bottom frame of the cylinder is fabricated in four sections. The bottom frame load-bearing plate is made of 20mm thick Q235A steel plate, the stiffening plates are made of 20mm thick Q235A steel, and the bottom plate is made of 20mm thick Q235A steel plate. The bottom frame is welded to the lower cylinder as a whole. During welding, the bottom frame plate is welded to the cylinder first, followed by the horizontal stiffening plates, the bottom plate, and the I-beams. After the bottom frame is assembled, the bottom edge of the I-beams is welded to the embedded parts of the station floor slab. The brackets must be secured to the station side walls with structural steel, and the upper part of the 150mm steel sleeve is secured to the middle plate beam with channel steel.

[0085] The working principle of the shield or pipe jacking 220 receiving construction method provided in this embodiment is as follows: First, the construction of the underground retaining structure 110 and the underground main structure 120 is completed to provide the basic structural conditions for the shield tunneling or pipe jacking 220 to receive the tunnel. The underground retaining structure 110 (such as a diaphragm wall) isolates the external soil and water from the interior of the underground main structure 120.

[0086] Secondly, a steel sleeve 150 is installed at the underground retaining structure 110 within the underground main structure 120, connecting the steel sleeve 150 to the underground main structure 120, and backfilling the steel sleeve 150 with soil 230. The steel sleeve 150 is connected to the underground main structure 120 via a ring-shaped embedded part 180, forming a sealed transition space. The backfilled soil 230 helps to balance the internal pressure of the steel sleeve 150 with the external water and soil pressure, preventing sudden inrush of external water and soil when the shield or pipe jacking 220 receives the casing.

[0087] Then, the tunnel boring machine (TBM) or pipe jacking machine 220 excavates and creates a structural hole in the underground retaining structure 110, which is then received into the steel sleeve 150. The cutterhead of the TBM or pipe jacking machine 220 cuts the underground retaining structure 110 (preferably made of fiberglass reinforcement 111) to form a structural hole, and the TBM or pipe jacking machine 220 enters the steel sleeve 150 to complete the receiving process.

[0088] Next, an annular frozen body 130 is formed around the tunnel segment or section 140 on the side of tunnel 210. By installing radial freezing pipes 170 around the tunnel segment or section 140 and freezing them, water in the strata surrounding the tunnel segment or section 140 freezes to form the annular frozen body 130. The inner side of the annular frozen body 130 contacts the tunnel segment or section 140, and the side closer to the underground retaining structure 110 contacts the underground retaining structure 110. The annular frozen body 130 forms a complete annular water-stopping barrier between the tunnel segment or section 140 and the underground retaining structure 110, effectively blocking the seepage of groundwater along the gap between the tunnel segment or section 140 and the underground retaining structure 110.

[0089] While maintaining the frozen state, the steel sleeve 150 is removed. The frozen body continues to provide a water-stopping function, so no water or soil will enter during the removal of the steel sleeve 150. After removing the steel sleeve 150, the gap between the annular embedded part 180 and the annular cover plate 142 is sealed by the sealing part 190 to maintain the seal at the opening.

[0090] While maintaining the frozen condition, the portal structure 160 at the structural opening is constructed. Under the protection of the frozen body, the portal structure 160 (including the outer portal) is poured between the underground main structure 120 and the segment or section 140, permanently connecting the station structure and the tunnel 210 structure.

[0091] Finally, the freezing was stopped, completing the entire receiving construction process. The annular frozen body 130 thawed after fulfilling its temporary waterproofing mission, without adversely affecting the permanent structure.

[0092] refer to Figure 13 , Figure 13This is a schematic diagram of the structure after freezing the soil around the tunnel segments or sections 140 on the side of the tunnel 210 to form a ring-shaped frozen body 130 in the shield tunneling or pipe jacking 220 launching construction method of this embodiment. This embodiment also provides a shield tunneling or pipe jacking 220 launching construction method, including: Construction of underground retaining structure 110 and underground main structure 120 is underway. Install and debug the tunnel boring machine or pipe jacking, install the steel sleeve 150 at the entrance of the underground retaining structure 110 to be excavated within the underground main structure 120, and backfill the soil 230 between the steel sleeve 150 and the tunnel boring machine or between the steel sleeve and the pipe jacking. The end of the steel sleeve 150 that is far from the underground retaining structure 110 is sealed off, and the shield or jacking pipe 220 starts from the steel sleeve 150; The shield tunnel or pipe jacking 220 is excavated and a structural hole is excavated on the underground retaining structure 110, and the steel sleeve 150 is excavated. The soil around the tunnel segment or section 140 on the side of tunnel 210 is frozen to form an annular frozen body 130. The inner side of the annular frozen body 130 is in contact with the tunnel segment or section 140 on the side of tunnel 210, and the side of the annular frozen body 130 closest to the underground retaining structure 110 is in contact with the underground retaining structure 110. Remove the steel sleeve 150 while maintaining the freeze. While maintaining the freeze, complete the construction of the portal structure 160 at the structural opening; Stop freezing.

[0093] The difference between the receiving method and the launching method lies in that the shield or jacking pipe 220 excavates from inside the steel sleeve 150 to the outside. The steel sleeve 150 is installed at the portal of the underground retaining structure 110 within the underground main structure 120, and the end of the steel sleeve 150 away from the underground retaining structure 110 is sealed. After the shield or jacking pipe 220 is assembled inside the steel sleeve 150, it launches, cutting through the underground retaining structure 110 (preferably made of fiberglass reinforcement 111) to form a structural tunnel, and excavates out of the steel sleeve 150 to enter the external strata. After the shield or jacking pipe 220 excavates out of the steel sleeve 150, an annular frozen body 130 is formed around the tunnel segment or section 140 on the side of the tunnel 210. While maintaining the frozen condition, the steel sleeve 150 is removed and the portal structure 160 is constructed.

[0094] The annular freezing body 130 provides water-stopping protection during the shield or pipe jacking 220 receiving process. The freezing pipe is less prone to blockage during the construction of the underground retaining structure 110 and less likely to be damaged during the shield or pipe jacking 220 receiving process. Therefore, the soil freezing stability is high, thus improving construction safety. The annular freezing body 130 only needs to form an annular freeze around the segment or pipe section 140. Compared to existing technologies that require large-area horizontal freezing, this method has a smaller freezing volume, shorter freezing time, and higher construction efficiency. While maintaining the freeze, the steel sleeve 150 is removed and the portal structure 160 is constructed, ensuring a reliable water-stopping barrier throughout the entire launching process and avoiding the risks of water inrush and mudslides. No surface dewatering wells are required, avoiding the impact of dewatering construction on the surrounding environment. Large-area cement-based reinforcement is also unnecessary, resulting in low construction costs and minimal environmental impact. It has a wide range of applications, suitable for both earth pressure balance shield tunnels and slurry balance shield tunnels. The launching and receiving methods have a high degree of consistency in the process flow, simplifying construction organization and personnel training.

[0095] The construction method described in this embodiment is applicable to both the launching and receiving of pipe jacking and the launching and receiving of tunnel boring machines.

[0096] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A method of shield or pipe jacking reception construction, characterized in that, include: Construction of underground retaining structures and underground main structures; Install steel sleeves at the underground retaining structure within the underground main structure to connect the steel sleeves to the underground main structure, and backfill the steel sleeves with soil. The tunnel boring machine or pipe jacking excavates a structural hole in the underground retaining structure and receives the tunnel into the steel sleeve. The soil around the tunnel segments or sections is frozen to form a ring-shaped frozen body. The inside of the ring-shaped frozen body is in contact with the tunnel segments or sections, and the side of the ring-shaped frozen body closest to the underground retaining structure is in contact with the underground retaining structure. Remove the steel sleeve while maintaining the freeze. Complete the construction of the portal structure at the structural opening while maintaining the freeze. Stop freezing.

2. The shield or pipe jacking receiving construction method according to claim 1, characterized in that, By setting multiple radial freezing pipes around the tunnel segments or sections and freezing the radial freezing pipes, the soil around the tunnel segments or sections is frozen to form a ring-shaped frozen body.

3. The shield or pipe jacking receiving construction method according to claim 2, wherein Radial freezing pipes are evenly distributed around the pipe segments or sections, and are arranged in multiple rows along the longitudinal direction of the tunnel.

4. The shield or pipe jacking receiving construction method according to claim 1, wherein When installing the steel sleeve at the underground retaining structure within the underground main structure, a ring-shaped embedded part connecting the underground retaining structure and the steel sleeve is also installed. The ring-shaped embedded part is installed on the inner side of the connection between the underground main structure and the steel sleeve.

5. The method according to claim 4, wherein After the tunnel boring machine (TBM) is received into the steel sleeve, the segments or sections inside the steel sleeve include the structural body and an annular cover plate installed on the outer ring of the structural body.

6. The shield or pipe jacking receiving construction method according to claim 5, wherein During the removal of the steel sleeve, the gap between the end of the annular embedded part away from the underground retaining structure and the annular cover plate is sealed with a sealing component.

7. The shield or pipe jacking receiving construction method according to claim 6, wherein The sealing component is welded to the annular embedded component and the annular cover plate.

8. The shield or pipe jacking receiving construction method according to claim 1, wherein Before forming a ring-shaped frozen body around the tunnel segments or sections, secondary grouting is performed on the segments or sections.

9. The shield or pipe jacking receiving construction method according to claim 1, wherein When constructing underground retaining structures, fiberglass reinforcement is used to create underground retaining structures where structural openings are required.

10. A method for initiating shield tunneling or pipe jacking construction, characterized in that, include: Construction of underground retaining structures and underground main structures; Install and debug the tunnel boring machine or pipe jacking, install steel sleeves at the entrance of the underground retaining structure to be excavated in the underground main structure, and backfill soil between the steel sleeve and the tunnel boring machine or between the steel sleeve and the pipe jacking. The end of the steel sleeve that is far from the underground retaining structure is sealed off, and the tunnel boring machine or pipe jacking machine starts from the steel sleeve; The tunnel boring machine (TBM) or pipe jacking machine excavates a structural hole in the underground retaining structure and then excavates a steel sleeve. The soil around the tunnel segments or sections is frozen to form a ring-shaped frozen body. The inside of the ring-shaped frozen body is in contact with the tunnel segments or sections, and the side of the ring-shaped frozen body closest to the underground retaining structure is in contact with the underground retaining structure. Remove the steel sleeve while maintaining the freeze. Complete the construction of the portal structure at the structural opening while maintaining the freeze. Stop freezing.

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