Long-distance shield tail sealing method for shield machine

Abstract

This invention discloses a method for sealing the tail of a tunnel boring machine (TBM) during long-distance tunneling operations. By analyzing the risk and location of tail leakage, the method utilizes a tail brush structure that allows for quick installation and removal, and a grease-filled auxiliary tail brush to achieve rapid sealing of long-distance tail leakage. This allows for flexible use of different tail brush rings and greases in different tunneling sections. When solving localized tail leakage problems, the grease-filled auxiliary tail brush enables rapid sealing of localized tail leakage. When solving multi-point or high-risk tail leakage problems, the quick-installation tail brush structure enables rapid sealing of multi-point tail leakage. This method ensures tail sealing safety while controlling grease consumption and reducing tail friction.

Description

Technical Field

[0001] This invention relates to the field of shield design and construction technology, and more specifically to a method for sealing the tail of a shield machine in long-distance shield tunneling operations. Background Technology

[0002] In recent years, the development of long, large, and deep river-crossing and sea-crossing tunnels has been rapid. Ultra-large diameter river-crossing tunnels almost universally encounter problems such as complex geological conditions, high water pressure, and long shield tunneling distances. Constructing shield tunnels under complex conditions presents enormous challenges to tunnel builders. Furthermore, influenced by factors such as the shield tail installation process (multiple joints), sudden changes in water and soil pressure, and uneven soil distribution, the risk of shield tail leakage under high water head pressure, especially in quicksand strata, is undoubtedly a focal point and a major concern for all projects.

[0003] Currently, common control methods to reduce the risk of shield tail leakage include adding multiple shield tail brushes, using redundant safety designs to create multiple shield tail brush cavities, and selecting high-quality, high-value shield tail sealing grease (with good grease indicators) to improve the sealing effect of the shield tail grease sealing cavities. Currently, the shield tail of common highway tunnel shields is generally configured with 3 wire brushes + 1 wire and steel plate bundle. However, with the development of large-diameter shields, to improve the shield tail sealing effect, the shield tail is generally configured with 4 wire brushes + 1 wire and steel plate bundle, forming 4 shield tail sealing grease sealing cavities, thereby improving the shield tail sealing effect when the shield passes through high water pressure and easily abrasive strata. With the development of large-diameter shield tunneling projects, the tunneling distance is becoming increasingly longer. However, extremely high water and soil pressure only exists in some deep trenches and V-shaped slope changes in the river center. The length of high water pressure or water-rich sand layers in areas crossing rivers and seas is generally small or only in a certain section. Setting up 4 wire brushes + 1 wire and steel plate bundle throughout the entire shield tunneling process is a redundant safety design, which will undoubtedly increase the burden on the shield tunneling. At the same time, the additional grease sealing cavity will result in a huge consumption of grease at the shield tail, which is detrimental to green shield tunneling and the control of construction costs. Moreover, long-distance tunneling weakens the effectiveness of the five brushes and four cavities. When the five brushes and four cavities are needed to play their role, they will not be able to achieve the effect of shield tail reinforcement.

[0004] Compared to the four-brush, three-cavity shield tail design, the five-brush, four-cavity shield tail design increases the shield tail length. During long-distance tunneling, the shield tail brushes 1-2 cavities away from the shield tail are prone to local wear or grout leakage. When replacing the shield tail brushes locally, it generally takes 5-10 days to complete the replacement. Considering the impact of shield tunneling schedule and daily economic cost, how to effectively reduce the wear of the shield tail brushes and achieve the purpose of rapid sealing and replacement of the tail brushes is a key issue for ensuring the safety of the shield tail in current shield tunneling.

[0005] To address the challenges of balancing economic selection of the tail brush and ensuring tail sealing safety when tunnel boring machines (TBMs) traverse complex and variable geological formations or pass under high-water-pressure lakes and seas, a tail brush design and method for rapid sealing and replacement of localized leaks at the TBM tail is urgently needed. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention proposes a method for sealing the tail of a tunnel boring machine (TBM) during long-distance tunneling operations. By analyzing the risk and location of tail leakage, this method utilizes a tail brush structure that allows for quick installation and removal, and a grease-filled auxiliary tail brush area to achieve rapid sealing of long-distance tail leakage. This allows for flexible use of different tail brush rings and grease in different tunneling sections. When addressing localized tail leakage, the grease-filled auxiliary tail brush area enables rapid sealing. When addressing multi-point or high-risk tail leakage, the quick-installation tail brush structure enables rapid sealing. This method ensures tail sealing safety while controlling grease consumption and reducing tail friction.

[0007] To achieve the above-mentioned technical objectives, the present invention employs the following technical means:

[0008] A method for sealing the tail of a tunnel boring machine (TBM) during long-distance tunneling operations involves pre-setting grease injection channels at the tail of the TBM and reserving circumferential tail brush installation holes. This allows the TBM to adjust the number of tail brushes and grease sealing chambers as needed based on different working environments during tunneling. These working environments include the following three conditions:

[0009] The first working environment scenario: When the shield tunneling machine passes through a stratum with a soil and water pressure of less than 0.3 MPa, N tail brush rings are installed on the tail shield section of the shield machine. The N tail brush rings form N-1 grease sealing cavities. Each tail brush ring is filled with hand-applied grease, and each grease sealing cavity is filled with tail grease. No tail brushes are installed on the reserved circumferential tail brush mounting holes.

[0010] The second working environment scenario: When there is localized leakage at the shield tail, additional shield tail brush blocks and grease bladders are installed at the leakage location to assist in sealing and achieve rapid plugging of long-distance shield tail leakage. The specific implementation measures are as follows:

[0011] A1. Stop tunneling operations, extend the shield machine cylinders to expose the fixing plate of the Nth shield tail brush ring, and monitor the shield tail leakage in real time.

[0012] A2. Clean the leaking area at the tail of the shield to expose the reserved circumferential tail brush installation holes;

[0013] A3. Install the locally added shield tail brush blocks. First, install the locally added shield tail brush blocks that are in contact with the grease sac. Then, install the locally added shield tail brush blocks that are not in contact with the grease sac. Evenly coat the inside of all locally added shield tail brush blocks with hand-applied grease. Next, install the locally added shield tail brush blocks located to the side of the grease sac. Install the grease sac between the Nth shield tail brush ring and the locally added shield tail brush blocks. Seal the localized leakage areas between the Nth shield tail brush ring and the locally added shield tail brush blocks by injecting shield tail grease into the grease sac, forming... Arc-shaped sealing area; small holes for the grease bladder are evenly opened on the top and sides of the grease bladder; after all the locally added shield tail brush blocks and grease bladders are installed, a rectangular sealing cavity is formed between the Nth shield tail brush ring, the locally added shield tail brush blocks, the tube segments and the shield shell. Shield tail grease is injected into the grease bladder through the preset grease injection channel. After each grease bladder is filled with shield tail grease, the locally added shield tail brush blocks away from the shield tail will be squeezed, so that the locally added shield tail brush blocks are in close contact with the tube segments, completely sealing the rectangular sealing cavity, thereby blocking the local leakage phenomenon of the shield tail in this area;

[0014] A4. Continue tunneling operations. During the tunneling process, the shield tail grease is injected into the grease bladder in real time to maintain close contact between the grease bladder, the segments, the Nth shield tail brush ring, and the locally added shield tail brush blocks. At the same time, the shield tail grease flowing out from the small holes of the grease bladder serves to both lubricate the segments and replenish the pressure of the sealed chamber.

[0015] The third working environment scenario: When the tunnel boring machine (TBM) is excavating into a high-water-pressure stratum with a soil-water pressure greater than 0.3 MPa, or when the TBM cross-section involves multiple strata, leading to increased risk of tail leakage due to poor TBM attitude control, the TBM should be stopped before crossing the strata to inspect and assess the possibility of tail brush leakage. If some tail brush plates have detached, or if there is excessive grout leakage or water seepage, a new tail brush should be added to the pre-reserved ring around the tail brush installation holes to form the N+1th tail brush ring. The inside of the added tail brush should be fully coated with hand-applied grease, and simultaneously, the Nth... Shield tail grease is injected into the grease sealing cavity four formed by the shield tail brush ring, the N+1th shield tail brush ring, and the tunnel segments. After the grease sealing cavity four is filled with shield tail grease, tunneling resumes, and the shield tail leakage is monitored at all times. When the shield tunneling machine completely passes through the high water pressure stratum with a water and soil pressure greater than 0.3 MPa or the shield tunneling section involves multiple strata, which increases the risk of shield tail leakage due to poor shield attitude control, the retention or removal of the N+1th shield tail brush ring is evaluated based on the remaining shield tunneling mileage and the remaining stratum environment.

[0016] In step A3, before installing the locally added shield tail brush block, first install the shield tail brush positioning block to mark the installation range of the shield tail brush base plate, so as to facilitate the accuracy of the installation of the locally added shield tail brush block.

[0017] In the second working environment, the shield shell of the shield tunneling machine is pre-set with a shield tail grease reserved hole. The shield tail grease reserved hole is connected to the oil inlet at the bottom of the grease bladder. After the grease bladder is installed, shield tail grease is injected into the grease bladder through the grease injection pipeline and the shield tail grease reserved hole. At the same time, the chamber formed by the grease bladder and the shield tail brush is injected with shield tail grease through the shield tail grease reserved hole.

[0018] In step A1 of the second working environment, the leakage point is located using an endoscope, and the leakage point is accurately marked using three-dimensional design software. Based on the marked location, the area for adding a shield tail brush block is determined on the reserved circumferential shield tail brush mounting hole.

[0019] In the third working environment, the possibility of leakage of the shield tail brush is checked and evaluated by using an endoscope and the shield tail slurry leakage. The sealing and wear of the N-1 shield tail brush and the Nth shield tail brush, which are far away from the shield tail segment, are also examined.

[0020] If some brush plates fall off in the N-1th and Nth shield tail brush rings, or if the grease pressure fluctuates by more than 30% or the grease pressure jumps frequently, it indicates that there has been grout leakage or water seepage in some or more locations. In this case, a shield tail brush is added to the entire ring around the reserved ring to form the N+1th shield tail brush ring.

[0021] In the third working environment scenario, the retention or removal of the N+1th shield tail brush ring is evaluated based on the remaining tunnel mileage and the remaining geological conditions. Specifically:

[0022] If the remaining tunnel length is no more than 300-500m and the remaining geological environment shield section passes through two or more types of geological strata at the same time, the N+1th shield tail brush ring shall be retained.

[0023] If the remaining tunnel length is greater than 500m and the remaining geological conditions are relatively uniform, then the N+1th shield tail brush ring should be removed.

[0024] The grease bladder is made of rubber and has a layered structure. After the grease bladder is filled with grease, it adheres closely to the tail brushes on both sides.

[0025] The side of the grease bladder that contacts the tube segment has a concave-convex drag-reducing surface.

[0026] The value of N is a positive integer greater than or equal to 4.

[0027] Beneficial effects:

[0028] Based on the design concept of refined management of shield tail seals, this invention proposes a tail brush design and application method for rapid sealing of local leakage at the shield tail of a tunnel boring machine (TBM). The beneficial effects are as follows:

[0029] 1) Based on the distribution of shield leakage points and the risk analysis of stratum leakage, a grease bladder auxiliary area tail brush is designed to enable rapid installation of local or concentrated shield tail leakage, and a whole ring structure that can be quickly installed and dismantled is added to solve the problem of multi-point leakage at the shield tail or crossing high-risk leakage areas.

[0030] 2) The design of the shield tail brush block with the assistance of the grease bladder to seal the shield tail leakage is that the grease bladder and the local tail brush form an arc-shaped sealed chamber, which not only achieves rapid sealing of local leakage at the shield tail, but also has a significant effect on solving local leakage at the shield tail.

[0031] 3) The design of the shield tail brush block with grease bladder to help seal the shield tail leakage avoids the work of replacing the tail brush due to wear of the tail brush at local points of the shield tail, greatly reduces the downtime of the shield machine, saves the cost of replacing the tail brush of the shield tail, and has significant economic benefits.

[0032] 4) The grease bladder structure is made of wear-resistant rubber material, with small leakage and pressure relief holes opened near the chamber and the tunnel segment side. This allows the bladder to change with the shield tail gap, while reducing friction with the tunnel segment structure and fully meeting the high efficiency requirements of shield tunneling.

[0033] 5) By pre-setting grease injection channels at the tail of the shield and reserving circumferential tail brush installation holes, the shield can change the number of tail brushes and grease sealing cavities at any time, thereby enhancing the tail sealing effect in areas with high water and soil pressure and special locations.

[0034] 6) When the shield tunnel passes through an environment with soil and water pressure <0.3MPa, the absence of the tail brush and grease sealing cavity will not increase the shield tunneling resistance, reduce the consumption of shield thrust, and help improve shield tunneling efficiency.

[0035] 7) Adding a tail brush means consuming an additional layer of grease to seal the shield tail. In long-distance shield tunneling, the economic burden of shield tail grease cannot be ignored.

[0036] 8) When the water and soil pressure of the shield tunneling is ≥0.3MPa or the shield attitude deteriorates and the risk of leakage at the shield tail increases sharply, a shield tail brush is installed at the reserved hole and filled with shield tail grease to add a safety barrier to the shield tail, greatly reducing the risk of leakage at the shield tail and truly achieving a win-win situation of shield tail sealing safety and economy. Attached Figure Description

[0037] Figure 1 This is a schematic diagram illustrating the rapid sealing and treatment of localized tail brush leakage.

[0038] Among them, 1 is the leakage sealing chamber; 2 is the shield tail brush positioning block; 3 is the locally added shield tail brush block located on one side of the grease bladder; 4 is the grease bladder; 5 is the shield tail brush ring near the shield tail; 6 is the locally added shield tail brush block; 7 is the reserved circumferential shield tail brush installation hole.

[0039] Figure 2 This is a cross-sectional view of the local tail brush leakage sealing device (1-1).

[0040] Among them, 8 is the small hole of the grease bladder; 9 is the thickened steel plate base of the tail brush; 10 is the preset grease injection channel; 11 is the connecting block between the grease bladder and the tail brush; and 12 is the quick positioning and installation plate.

[0041] Figure 3 This is section AA in the cross-sectional view of the local tail brush leakage sealing device 1-1.

[0042] Among them, 13 is a concave-convex drag-reducing surface;

[0043] Figure 4 This is a schematic diagram showing the arrangement of multiple shield tail brushes and sealing cavities.

[0044] Among them, 31 is the shield tail shell structure; 32 is the outer contour line of the grease pipeline laid inside the shield shell; 33 is the grease pipeline laid at the shield tail; 34 is the control connection port between the grease pipeline and the grease sealing cavity; 35 is the synchronous grout behind the shield tail; 36 is the connection line between adjacent segments at the shield tail; 37 is the first shield tail brush ring; 38 is the first grease sealing cavity; 39 is the second shield tail brush ring; 40 is the second grease sealing cavity; 41 is the third shield tail brush ring; 42 is the segment that has not detached from the shield tail; 43 is the third grease sealing cavity; 44 is the inner contour line of the grease pipeline laid inside the shield shell; 45 is the fourth shield tail brush ring; 46 is the fourth grease sealing cavity; 47 is the outer contour line of the segment that has not detached from the shield tail; 49 is the inner contour line of the segment that has not detached from the shield tail; 51 is the tail brush fixing bolt structure; 52 is the grease injection port control valve of the fifth and fourth shield tail grease cavities.

[0045] Figure 5 A schematic diagram showing the layout of multiple grease sealing cavity injection pipelines on the shield tail ring.

[0046] Among them, 31 is the shield tail shell structure of the shield tunnel; 32 is the outer contour line of the grease pipes laid inside the shield shell; 201 is the trajectory line of the grease pipes laid on the shield tail; 202 is the inner contour line of the shield tail.

[0047] Figure 6 This is a schematic diagram showing the grease sealing chambers corresponding to multiple grease lines.

[0048] Among them, 300 is the grease pipe; 301 is the grease outlet of the grease pipe connected to the fourth grease sealing cavity; 302 is the grease outlet of the grease pipe connected to the third grease sealing cavity; 303 is the grease outlet of the grease pipe connected to the second grease sealing cavity; and 304 is the grease outlet of the grease pipe connected to the first grease sealing cavity.

[0049] Figure 7 A top-down view showing the addition of a tail brush to address localized leakage at the shield tail of a tunnel boring machine.

[0050] Among them, 60 is the tail brush plate structure; 61 is the shield tail edge structure; 62 is the circular trajectory line away from the shield tail; and 63 is the local leakage area at the shield tail caused by severe wear of the shield tail brush or the tail brush falling off.

[0051] Detailed Description of Embodiments To better understand the present invention, the following detailed description is provided in conjunction with the accompanying drawings and embodiments:

[0052] All directional indicators used in this invention are based on the ground as a reference system. The longitudinal direction is the tunneling direction of the shield, and the lateral direction is perpendicular to the tunneling direction. "Left" indicates the direction in which the tail brush moves away from the tunnel segment, and "right" indicates the direction in which the tail brush moves closer to the tunnel segment.

[0053] The shield tail brushes, from right to left, are the first shield tail brush ring, the second shield tail brush ring, the third shield tail brush ring, and the fourth shield tail brush ring.

[0054] This invention relates to the design and application method of a tail brush for rapid sealing of local leakage at the tail of a tunnel boring machine.

[0055] (1) Four brushes and three chambers in formations without high water pressure or leakage risk

[0056] In geological formations or tunneling environments with a low risk of tail leakage, the tail shield section of the tunnel boring machine (TBM) only installs the first, second, third, and fourth tail brush rings near the tunnel lining segments. These four tail brushes form three grease-sealed cavities. Each tail brush is filled with hand-applied grease, and each grease-sealed cavity is filled with tail grease. However, during the TBM manufacturing process, grease injection pipelines that can access the four grease-sealed cavities must be pre-fabricated and installed. Under normal tunneling conditions, the grease injection control valve to the fourth grease-sealed cavity is closed. During tunneling, depending on the TBM's tunneling rate, the valves connecting to the first, second, and third grease-sealed cavities are opened. The third grease injection pipeline control valve fills each grease sealing cavity with grease at the tail of the shield, and replenishes and monitors it in real time as the shield advances. However, the reserved fifth tail brush installation hole is not installed initially, so a closed-loop grease sealing cavity cannot be formed. This reduces the number of tail grease sealing cavities and tail brushes. On the one hand, the absence of additional tail brushes and grease sealing cavities will not increase the shield tunneling resistance, reducing the consumption of shield thrust and helping to improve shield tunneling efficiency. On the other hand, adding a tail brush means consuming an additional grease sealing cavity at the tail of the shield. In long-distance shield tunneling, the economic burden of tail grease cannot be ignored.

[0057] (2) When there is localized shield tail leakage, additional shield tail brush blocks and grease bladders are added to assist in sealing to achieve rapid sealing of long-distance shield tail leakage.

[0058] When the tunnel boring machine (TBM) is operating in strata with a low risk of tail leakage or in tunneling environments, the tail brush is typically installed with four brushes and three chambers. However, the TBM design often includes a five-brush, four-chamber configuration for grease piping and tail brush installation holes. If localized tail leakage occurs during tunneling, partial tail brush replacement is generally required. However, each replacement takes approximately seven days, which is detrimental to the TBM's progress and economic efficiency. Therefore, a device and method for the rapid sealing and installation of locally added tail brush blocks are designed.

[0059] When localized shield tail leakage occurs, the leakage point is located using an endoscope, and the area to be added with additional shield tail brush blocks is determined using CAD software. Specific implementation measures are as follows:

[0060] 1. Stop tunneling operations immediately, extend the shield machine cylinders until the fourth shield tail brush fixing plate is exposed at the shield tail, and monitor the shield tail leakage in real time;

[0061] 2. After identifying the leakage area, clean the leakage area, especially the reserved circumferential shield tail brush installation holes;

[0062] 3. Install additional shield tail brush blocks in the leakage area. The additional shield tail brush blocks include multiple blocks, with 3 to 5 blocks arranged in the circumferential direction. The brush plate of each additional shield tail brush block is manually coated with hand-applied grease.

[0063] 4. The fourth shield tail brush ring and the locally added shield tail brush block are connected by a rubber grease bladder to form a "U"-shaped sealing area. The grease bladder is connected to the wire brush base by anchor bolts and is installed as a whole at the shield tail shell. The bottom of the grease bladder is connected to the pre-set grease injection channel of the shield tail. Small holes for the grease bladder are opened on the top and side surfaces of the grease bladder.

[0064] 5. After all the locally added shield tail brush blocks and grease bladders are installed, a rectangular sealing cavity is formed between the fourth shield tail brush ring, the locally added shield tail brush blocks, the tube segments and the shield shell. After installation, shield tail grease is injected into the grease bladder through the preset grease injection channel. At the same time, shield tail grease is injected into the rectangular sealing cavity through the preset grease injection channel of the shield tail. The entire rectangular sealing cavity can solve the problem of local shield tail leakage.

[0065] 6. During the tunnel boring machine (TBM) excavation, the grease in the grease bladder is injected into the grease bladder in real time to maintain a tight fit between the grease bladder and the segments and tail brush. At the same time, the grease flowing out of the grease bladder through the evenly spaced small holes can serve the dual purpose of lubricating the segments and pressurizing the sealed chamber.

[0066] (3) Rapid installation and dismantling of the entire shield tail in environments with high risk of leakage or high water pressure:

[0067] When the tunnel boring machine (TBM) is excavating into high-water-pressure strata (soil pressure > 0.3 MPa) or environments with high leakage risk at the shield tail (such as water-rich sand layers), the TBM should be stopped before crossing the strata. An endoscope and examination of the shield tail slurry leakage should be used to check and assess the possibility of leakage in the shield tail brush. Particular attention should be paid to checking the sealing and wear of the inner third and fourth shield tail brush rings, which are furthest from the shield tail segments. If some brush plates on the shield tail brush have detached or the grease chamber has poor pressure stabilization, indicating excessive slurry leakage or water seepage, additional shield tail brushes should be installed around the pre-reserved ring at the corresponding installation holes, forming the second ring. Install the fifth shield tail brush ring and fill the tail brush with hand-applied grease. At the same time, open the grease injection control valve to inject grease into the grease sealing chamber four and check the grease injection status of the shield tail to prevent grease pipeline blockage. If blockage occurs, clear the pipeline in time. Once the grease pipeline can smoothly inject shield tail grease into the grease sealing chamber four, the tunneling will resume after all preparations are complete. Monitor the shield tail leakage status at all times when the shield passes through high water pressure strata or shield tail leakage risk environments. After the shield has completely passed through, evaluate the retention or removal of the added fifth shield tail brush ring based on the remaining shield mileage and the remaining strata environment.

[0068] Figure 1 This diagram illustrates the use of grease bladders in locally added tail shield brush blocks to assist in sealing tail shield leaks. The grease bladders in these locally added tail shield brush blocks are primarily used to address localized tail shield leaks in the tunnel boring machine (TBM). When a localized leak occurs, the location of the leak is marked on the tail shield brush ring 5 near the tail shield. The leak area is then cleaned to expose the pre-drilled circumferential tail shield brush mounting holes 7. Tail shield brush positioning blocks 2 are then installed, and the installation range of the tail shield brush base plate is marked to ensure accurate installation. After the positioning blocks 2 are installed, the locally added tail shield brush blocks that contact the grease bladder are installed first, followed by the locally added tail shield brush blocks that do not contact the grease bladder. All locally added tail shield brush blocks are evenly coated with hand-applied grease. Finally, the locally added tail shield brush blocks located on the side of the grease bladder are installed in place. The locally added tail shield brush blocks located on the side of the grease bladder are as follows: Figure 2 As shown.

[0069] After all the locally added shield tail brush blocks and grease bladders are installed, a rectangular sealing cavity 1 is formed between the Nth shield tail brush ring, the locally added shield tail brush blocks, the tube segments, and the shield shell. Using a grease injection pipeline leading to the grease bladder, shield tail grease is injected into the grease bladder 4. After each grease bladder is filled with shield tail grease, it will squeeze the locally added shield tail brush blocks 6 that are far away from the shield tail, so that the shield tail brushes are in close contact with the tube segments, thereby sealing the local leakage phenomenon of the shield tail in this area.

[0070] Figure 2 The diagram shows a cross-sectional view of the local tail brush leakage sealing device AA, which mainly reflects the arrangement of the grease bladder between the tail brush ring 5 near the tail of the shield and the locally added tail brush block 6 far from the tail of the shield.

[0071] As a preferred embodiment of the present invention, the grease bladder 4 is made of rubber and has a multi-layered structure. Under the action of the grease injection channel 10, the grease bladder 4 is filled with grease and closely adheres to the shield tail brushes on both sides to achieve a sealing effect. The grease injection channel 10 is provided on the grease bladder 4. When the pressure inside the grease bladder 4 is too high, the grease injection channel 10 will leak excess grease into the sealing cavity. On the one hand, this fills the sealing cavity with grease, enhancing the sealing effect of the shield tail; on the other hand, it reduces the frictional resistance between the shield tail brush and the tunnel segments, reduces shield tail wear, and reduces the shield tunneling resistance.

[0072] Figure 3 The image shows the AA section and the BB section section of the local tail brush leakage sealing device.

[0073] Figure 4 This diagram illustrates the arrangement of multiple tail brushes and sealing cavities. In strata with low risk of tail leakage or in tunneling environments, the tail shield of the tunnel boring machine (TBM) is equipped with only four tail brush rings near segment 42. From right to left, these are the first tail brush ring 37, the second tail brush ring 39, the third tail brush ring 41, and the fourth tail brush ring 45. Three grease-sealed cavities are formed beneath these four tail brushes. Each tail brush is filled with hand-applied grease, and each grease-sealed cavity is filled with tail grease. However, during the TBM manufacturing process, a grease injection pipeline (3) that connects to the four grease-sealed cavities must be pre-fabricated and installed. Under normal tunneling conditions, the grease injection control valve 52, which injects into the fourth grease-sealed cavity, is closed. During tunneling, the valve 52, which connects to the first grease-sealed cavity 38, is opened according to the TBM tunneling rate. The grease injection pipeline control valves of sealing cavity two 40 and grease sealing cavity three 43 fill each grease sealing cavity with grease from the shield tail, and replenish and monitor it in real time as the shield advances. However, the grease sealing cavity four 46 cannot be formed because the reserved circumferential shield tail brush installation holes are not installed at the beginning. This reduces the number of shield tail grease sealing cavities and shield tail brushes. On the one hand, the absence of additional shield tail brush blocks and grease sealing cavities will not increase the shield tunneling resistance and reduce the consumption of shield thrust, which helps to improve shield tunneling efficiency. On the other hand, adding a shield tail brush ring means consuming an additional grease sealing cavity for the shield tail. In long-distance shield tunneling, the economic burden of shield tail grease cannot be ignored.

[0074] When the tunnel boring machine (TBM) reaches a high-water-pressure stratum or an environment with a high risk of leakage at the tail of the shield, it should be stopped before the TBM passes through the stratum. An endoscope and examination of the tail slurry leakage should be used to check and assess the possibility of leakage in the tail brush. Particular attention should be paid to checking the sealing and wear of the innermost third and fourth tail brushes (41 and 45) furthest from the tail segments. If the wear on the tail brushes is minimal, meaning there has been no slurry leakage or water seepage, a fifth tail brush ring should be added around the pre-installed tail brush mounting holes, forming a full ring. The inside of the tail brush should be fully coated with a hand-applied coating. Simultaneously, open the grease injection control valve 52, which injects grease into the grease sealing chamber 46, and check the grease injection status at the shield tail to prevent grease pipeline blockage. If blockage occurs, clear the pipeline promptly. Once the grease pipeline can smoothly inject shield tail grease into the grease sealing chamber 46, proceed. After all preparations are complete, resume tunneling, and continuously monitor the shield tail leakage situation when the shield passes through high water pressure strata or environments with high shield tail leakage risk. After the shield has completely passed through, assess the decision of whether to add a fifth shield tail brush based on the remaining shield mileage and the remaining geological conditions. Specifically:

[0075] If the remaining tunnel length is no more than 300-500m and the remaining geological environment shield section passes through two or more types of geological strata at the same time, the N+1th shield tail brush ring shall be retained.

[0076] If the remaining tunnel length is greater than 500m and the remaining geological conditions are relatively uniform, then the N+1th shield tail brush ring should be removed.

[0077] Figure 5 This diagram illustrates the layout of the grease injection pipelines for multiple grease sealing cavities on the shield tail ring. To visually demonstrate the grease injection into each shield tail grease sealing cavity, the grease pipelines are evenly distributed along the shield tail ring, with the pipelines installed in the inner edge area of ​​the shield tail ring.

[0078] Figure 6 This diagram illustrates the multiple grease lines corresponding to the grease sealing cavities. Since the grease lines at the shield tail need to inject grease into grease sealing cavities at different distances, the grease lines 300 laid out on the inner arc surface of the shield tail exhibit varying lengths. The farther the distance from the shield tail segment, the shorter the grease lines. Based on the shield tail brush layout distance, the grease outlet 301 of the grease line connected to grease sealing cavity four injects grease towards grease sealing cavity four; the grease outlet 302 of the grease line connected to grease sealing cavity three injects grease towards grease sealing cavity three; the grease line interface 303 injects grease towards grease sealing cavity two; and the grease outlet 304 of the grease line connected to grease sealing cavity one injects grease towards grease sealing cavity one.

[0079] Figure 7 for Figure 1 A top-down view of the addition of a tail brush when there is localized leakage at the tail of the shield tunnel.

Claims

1. A method for sealing the tail of a tunnel boring machine (TBM) during long-distance shield tunneling operations, characterized in that... By pre-setting grease injection channels at the tail of the shield and reserving circumferential tail brush installation holes, the shield can change the number of tail brushes and grease sealing chambers at any time according to different working environment conditions during tunneling. The working environment conditions include the following three: The first working environment scenario: When the shield tunneling machine passes through a stratum with a soil and water pressure of less than 0.3 MPa, N tail brush rings are installed on the tail shield section of the shield machine. The N tail brush rings form N-1 grease sealing cavities. Each tail brush ring is filled with hand-applied grease, and each grease sealing cavity is filled with tail grease. No tail brushes are installed on the reserved circumferential tail brush mounting holes. The second working environment scenario: When there is localized leakage at the shield tail, additional shield tail brush blocks and grease bladders are installed at the leakage location to assist in sealing and achieve rapid plugging of long-distance shield tail leakage. The specific implementation measures are as follows: A1. Stop tunneling operations, extend the shield machine cylinders to expose the fixing plate of the Nth shield tail brush ring, and monitor the shield tail leakage in real time. A2. Clean the leaking area at the tail of the shield to expose the reserved circumferential tail brush installation holes; A3. Install the locally added shield tail brush blocks. First, install the locally added shield tail brush blocks that are in contact with the grease sac. Then, install the locally added shield tail brush blocks that are not in contact with the grease sac. Evenly coat the inside of all locally added shield tail brush blocks with hand-applied grease. Next, install the locally added shield tail brush blocks located to the side of the grease sac. Install the grease sac between the Nth shield tail brush ring and the locally added shield tail brush blocks. Inject shield tail grease into the grease sac to seal the localized leakage area between the Nth shield tail brush ring and the locally added shield tail brush blocks, forming an arc-shaped sealing area. Small holes for the grease bladder are evenly opened on the top and sides of the grease bladder. After all the locally added shield tail brush blocks and grease bladders are installed, a rectangular sealing cavity (1) is formed between the Nth shield tail brush ring (5), the locally added shield tail brush blocks, the tube segments and the shield shell. Shield tail grease is injected into the grease bladder (4) using the preset grease injection channel. After each grease bladder is filled with shield tail grease, the locally added shield tail brush blocks that are far away from the shield tail will be squeezed to make the locally added shield tail brush blocks fit tightly with the tube segments, and the rectangular sealing cavity (1) will be completely sealed, thereby blocking the local leakage phenomenon of the shield tail in this area. A4. Continue tunneling operations. During the tunneling process, the shield tail grease is injected into the grease bladder in real time to maintain close contact between the grease bladder, the segments, the Nth shield tail brush ring, and the locally added shield tail brush blocks. At the same time, the shield tail grease flowing out from the small holes of the grease bladder serves to both lubricate the segments and replenish the pressure of the sealed chamber. The third working environment scenario: When the tunnel boring machine (TBM) is excavating into a high-water-pressure stratum with a soil-water pressure greater than 0.3 MPa, or when the TBM cross-section involves multiple strata, leading to increased risk of tail leakage due to poor TBM attitude control, the TBM should be stopped before crossing the strata to inspect and assess the possibility of tail brush leakage. If some tail brush plates have detached, or if there is excessive grout leakage or water seepage, a new tail brush should be added to the pre-reserved ring around the tail brush installation holes to form the N+1th tail brush ring. The inside of the added tail brush should be fully coated with hand-applied grease, and simultaneously, the Nth... Shield tail grease is injected into the grease sealing cavity four formed by the shield tail brush ring, the N+1th shield tail brush ring, and the tunnel segments. After the grease sealing cavity four is filled with shield tail grease, tunneling resumes, and the shield tail leakage is monitored at all times. When the shield tunneling machine completely passes through the high water pressure stratum with a water and soil pressure greater than 0.3 MPa or the shield tunneling section involves multiple strata, which increases the risk of shield tail leakage due to poor shield attitude control, the retention or removal of the N+1th shield tail brush ring is evaluated based on the remaining shield tunneling mileage and the remaining stratum environment.

2. The method for sealing the tail of a tunnel boring machine in long-distance shield tunneling operations according to claim 1, characterized in that, In step A3, before installing the locally added shield tail brush block, first install the shield tail brush positioning block (2) to mark the installation range of the shield tail brush base plate, so as to facilitate the accuracy of the installation of the locally added shield tail brush block.

3. The method for sealing the tail of a tunnel boring machine in long-distance shield tunneling operations according to claim 1, characterized in that, In the second working environment, the shield shell of the shield tunneling machine is pre-set with a shield tail grease reserved hole. The shield tail grease reserved hole is connected to the oil inlet at the bottom of the grease bladder. After the grease bladder is installed, shield tail grease is injected into the grease bladder through the pre-set grease injection channel and the shield tail grease reserved hole. At the same time, the chamber formed by the grease bladder and the shield tail brush is pressure stabilized by injecting shield tail grease through the shield tail grease reserved hole and the side hole of the grease bladder.

4. The method for sealing the tail of a tunnel boring machine in long-distance shield tunneling operations according to claim 1, characterized in that, In step A1 of the second working environment, the leakage point is located using an endoscope, and the leakage point is accurately marked using three-dimensional design software. Based on the marked location, the area for adding a shield tail brush block is determined on the reserved circumferential shield tail brush mounting hole.

5. The method for sealing the tail of a tunnel boring machine in long-distance shield tunneling operations according to claim 1, characterized in that, In the third working environment, the possibility of leakage of the shield tail brush is checked and evaluated by using an endoscope and the shield tail slurry leakage. The sealing and wear of the N-1 shield tail brush and the Nth shield tail brush, which are far away from the shield tail segment, are also examined. If some brush plates fall off in the N-1th and Nth shield tail brush rings, or if the grease pressure fluctuates by more than 30% or the grease pressure jumps frequently, it indicates that there has been grout leakage or water seepage in some or more locations. In this case, a shield tail brush is added to the entire ring around the reserved ring to form the N+1th shield tail brush ring.

6. The method for sealing the tail of a tunnel boring machine in long-distance shield tunneling operations according to claim 1, characterized in that, In the third working environment scenario, the retention or removal of the N+1th shield tail brush ring is evaluated based on the remaining tunnel mileage and the remaining geological conditions. Specifically: If the remaining tunnel length is no more than 300-500m and the remaining geological environment shield section passes through two or more types of geological strata at the same time, the N+1th shield tail brush ring shall be retained. If the remaining tunnel length is greater than 500m and the remaining geological conditions are relatively uniform, then the N+1th shield tail brush ring should be removed.

7. The method for sealing the tail of a tunnel boring machine in long-distance shield tunneling operations according to claim 1, characterized in that, The grease bladder is made of rubber and has a layered structure. After the grease bladder is filled with grease, it adheres closely to the tail brushes on both sides.

8. The method for sealing the tail of a tunnel boring machine in long-distance shield tunneling operations according to claim 7, characterized in that, The side of the grease bladder that contacts the tube segment has a concave-convex drag-reducing surface.

9. The method for sealing the tail of a tunnel boring machine in long-distance shield tunneling operations according to claim 7, characterized in that, The value of N is a positive integer greater than or equal to 4.

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