Double-shield TBM (tunnel boring machine)

Abstract

The utility model provides a double-shield TBM, and belongs to the field of tunneling equipment. The double-shield TBM comprises a telescopic outer shield and a telescopic inner shield, an annular gap is formed between the inner circumferential face of the telescopic outer shield and the outer circumferential face of the telescopic inner shield, an integrated annular first sealing strip or at least two first sealing strips forming an annular shape are arranged in the annular gap, and the first sealing strips are in sliding sealing fit with the inner circumferential face of the telescopic outer shield; the inner side of the first sealing strip is provided with at least two arc-shaped plates forming an annular shape in a surrounding mode, the arc-shaped plates are fixedly connected with the first sealing strip, the arc-shaped plates are arranged on the telescopic inner shield in the radial direction in a guiding mode, and the double-shield TBM further comprises a pushing structure used for pushing the arc-shaped plates to move outwards in the radial direction after the first sealing strip is abraded. The pushing structure is arranged on the telescopic inner shield, an operator can conveniently disassemble the first sealing strip, and the arc-shaped plate used for dispersing the pushing force of the pushing structure is arranged for the first sealing strip, so that the sealing uniformity is improved.

Description

Technical Field

[0001] The utility model belongs to the field of tunneling equipment, in particular to a double-shield TBM. Background Art

[0002] The shield shell of a double-shield TBM typically consists of a front shield, a telescopic outer shield, a telescopic inner shield, a support shield, and a tail shield. During tunneling, the telescopic outer and inner shields undergo telescopic and relative yaw movements. To ensure these movements proceed smoothly, a gap must be maintained between the two shields. However, during construction, rock debris can easily enter this gap. Excessive accumulation can cause excessive frictional resistance to the relative movement of the two shields, potentially leading to machine downtime. Furthermore, when tunneling in complex strata, the high water pressure in the strata can cause sediment to spray into the main machine through the gap between the telescopic outer and inner shields. In severe cases, this can cause the main machine to shut down and require repairs.

[0003] To solve the above technical problems, a sealing strip can be provided between the telescopic inner shield and the telescopic outer shield. A method that is easy for a person skilled in the art to think of is to fix the sealing strip on one of the telescopic inner shield and the telescopic outer shield and slide it with the other. However, such a sealing strip will become ineffective immediately after being worn, resulting in a short service life. Moreover, since the sealing strip is directly fixed to the telescopic inner shield or the telescopic outer shield, it is inconvenient to replace it.

[0004] The existing Chinese utility model patent with authorization announcement number CN206071592U and authorization announcement date of April 5, 2017 discloses a sealed double-shield TBM, which TBM includes a telescopic outer shield, a telescopic inner shield and a sealing device. The telescopic outer shield is provided with a slide groove along the radial direction. The sealing device includes a dynamic sealing strip slidably installed in the slide groove. One radial end of the dynamic sealing strip extends out of the inner groove and is in contact with the outer peripheral surface of the telescopic inner shield. The other radial end of the dynamic sealing strip extends out of the outer groove of the slide groove. An outer shell is fixedly provided on the outer peripheral surface of the telescopic outer shield. One end of the dynamic sealing strip extends out of the outer groove of the slide groove and is located in the outer shell. An elastic member is provided in the outer shell to press the dynamic sealing strip so that the dynamic sealing strip can always be in close contact with the outer peripheral surface of the telescopic inner shield to prevent rock debris from entering the gap between the telescopic outer shield and the telescopic inner shield.

[0005] When the dynamic sealing strip of the TBM described in the aforementioned utility model patent becomes severely worn, the operator must remove the outer shell from the telescopic outer shield to replace the strip. However, during tunnel construction, there is insufficient space outside the telescopic outer shield to complete this removal. Furthermore, in the aforementioned TBM, the dynamic sealing strip, under the pressure of the elastic member, adheres tightly to the outer circumference of the telescopic inner shield. The range of action of the individual elastic members on the dynamic sealing strip is relatively small, resulting in uneven circumferential force on the dynamic sealing strip and, consequently, uneven sealing performance. Utility Model Content

[0006] The purpose of the utility model is to provide a double-shield TBM to solve the technical problems in the prior art of uneven sealing effect caused by uneven force on the dynamic sealing strip in the circumferential direction, and the technical problem of inconvenient removal of the dynamic sealing strip due to the dynamic sealing strip passing through the telescopic outer shield.

[0007] To achieve the above objectives, the technical solution of the double-shield TBM provided by the present invention is:

[0008] A double-shield TBM includes a telescopic outer shield and a telescopic inner shield. An annular gap is formed between the inner circumference of the telescopic outer shield and the outer circumference of the telescopic inner shield. An integral annular first sealing strip or at least two first sealing strips forming an annular shape are provided in the annular gap. The first sealing strip and the inner circumference of the telescopic outer shield are in sliding sealing engagement. At least two annular arc plates are provided on the inner side of the first sealing strip. The arc plates are fixedly connected to the first sealing strip and are radially guided on the telescopic inner shield. The double-shield TBM also includes a pushing structure for radially pushing the arc plates outward after the first sealing strip is worn.

[0009] As a further improvement, a second sealing strip is provided between the arc plate and the outer circumference of the telescopic inner shield, and the pushing structure has a telescopic output rod, the end of which radially penetrates the telescopic inner shield and is fixedly connected to the arc plate.

[0010] As a further improvement, it is defined that one end of the double-shield TBM excavation faces forward, and a flap is vertically provided at the front end of the arc plate. The flap is located in front of the telescopic inner shield, and a radially extending guide long hole is opened on the flap. A guide body is provided on the front end surface of the telescopic inner shield. The guide body has a guide part that passes through the guide long hole and is fixedly connected to the telescopic inner shield, and a limiting part that is fixed or integrally connected to the front end of the guide part. The guide part cooperates with the guide long hole. The limiting part is located on the front side of the flap and limits the forward movement of the flap.

[0011] As a further improvement, the guide body is a guide bolt, the rod of the guide bolt constitutes the guide portion and is threadedly connected to the telescopic inner shield, and the head of the guide bolt constitutes the limiting portion.

[0012] As a further improvement, a sealing gasket is provided between the circumferential end surfaces of two circumferentially adjacent arc-shaped plates, and the sealing gasket is fixedly connected to one of the arc-shaped plates.

[0013] As a further improvement, it is defined that one end of the double-shield TBM excavation faces forward, and the double-shield TBM also includes a plurality of cleaning nozzles for spraying water or air, and the spraying end of the cleaning nozzle is located between the arc plate and the telescopic outer shield and the spraying end is behind the first sealing strip.

[0014] As a further improvement, the cleaning nozzle is a straight tube, the nozzle of the cleaning nozzle is arranged on the axial end face of the cleaning nozzle outlet end, and the outlet end of the cleaning nozzle is tilted backward so that the airflow or water flow ejected from the cleaning nozzle flows tilted backward.

[0015] As a further improvement, the cleaning nozzle includes a straight pipe section and a bent section located at one end of the straight pipe section, the axis of the straight pipe section of the cleaning nozzle intersects the axis of the telescopic inner shield at right angles, the nozzle of the cleaning nozzle is arranged on the end face of the bent section, and the bent section bends backward or toward the tangent direction of the outer peripheral surface of the curved plate; or the cleaning nozzle is a straight pipe, the end face of one end of the cleaning nozzle extending between the curved plate and the telescopic outer shield is closed, and the nozzle for spraying water or air is opened on the circumferential surface of the spraying end, and the nozzle faces backward or toward the tangent direction of the outer peripheral surface of the curved plate.

[0016] As a further improvement, it is defined that one end of the double-shield TBM excavation faces forward, and the double-shield TBM also includes an oil injection pipe, which is installed on the telescopic inner shield, and the oil injection end of the oil injection pipe is located in the annular gap and in front of the first sealing strip.

[0017] As a further improvement, a detection device is fixedly installed on the inner side of the telescopic outer shield. The detection device is located in front of the first sealing strip and is used to detect the thickness of the first sealing strip. The double-shield TBM also includes a controller that receives signals from the detection device and issues action instructions to the pushing structure.

[0018] The double-shield TBM provided by this utility model is an invention that improves the relationship between key elements. The double-shield TBM first slidably engages the first sealing strip with the inner circumference of the telescopic outer shield, and then incorporates a push structure on the telescopic inner shield to compress the first sealing strip. This allows operators to remove the first sealing strip from within the double-shield TBM while the TBM is in the tunnel. Furthermore, a curved plate is provided on the inner side of the first sealing strip to evenly distribute the pushing force applied by the push structure, ensuring uniform force on the first sealing strip and a consistent sealing effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic structural diagram of an embodiment of a double-shield TBM in the present invention;

[0020] Figure 2 This is a diagram showing a state in which the curved plates of an embodiment of the double-shield TBM of the present invention are tightly attached to each other in the circumferential direction;

[0021] Figure 3 This is a diagram showing a state in which gaps appear between the curved plates in one embodiment of the double-shield TBM of the present invention;

[0022] Figure 4This is a schematic diagram of the cooperation between the flap and the limit bolt in one embodiment of the double-shield TBM of the present invention;

[0023] Figure 5 This is a schematic diagram of the connection relationship between the controller and the detection device, the push structure, the cleaning nozzle and the oil injection pipe in one embodiment of the double-shield TBM of the present invention.

[0024] Description of reference numerals:

[0025] 1. Telescopic outer shield; 2. Telescopic inner shield; 3. Arc plate; 4. Limit bolt; 5. Flap; 6. Guide hole; 7. Annular gap; 8. Sealing gasket; 9. First sealing strip; 10. Second sealing strip; 11. Pushing structure; 12. Cleaning nozzle; 13. Oil filling pipe; 14. Detection device; 15. Controller. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below with reference to the embodiments.

[0027] In order to solve the problems in the prior art, the basic concept of the present invention is to set the pushing structure on the telescopic inner shield to facilitate the operator to remove the first sealing strip, and to configure the first sealing strip with an arc-shaped plate for dispersing the pushing force of the pushing structure, thereby improving the uniformity of the seal.

[0028] Specific embodiment 1 of the double shield TBM provided by the utility model:

[0029] A double shield TBM, comprising a shield shell, a cutterhead and a main drive device, wherein the shield shell comprises a front shield, a telescopic outer shield 1, a telescopic inner shield 2, a support shield and a tail shield. Figure 1 The telescopic outer shield 1 is located in front of the telescopic inner shield 2, the front end of the telescopic inner shield 2 is nested in the rear end of the telescopic outer shield 1, and an annular gap 7 is formed between the inner circumference of the telescopic outer shield 1 and the outer circumference of the telescopic inner shield 2 at the position where the telescopic outer shield 1 and the telescopic inner shield 2 cooperate.

[0030] See attached Figure 1 and attached Figure 2 A plurality of annular arc plates 3 are arranged in the annular gap 7. Since the arc plates 3 need to move radially along the annular gap 7, at least two arc plates 3 need to be set. When in use, the number of arc plates 3 can be selected according to the size of the double-shield TBM.

[0031] A sealing gasket 8 is provided between two circumferentially adjacent arc-shaped plates 3, see the attached Figure 2 , Attachment Figure 3 and attached Figure 4, the sealing gasket 8 is fixedly connected to one of the curved plates 3, and the specific fixing method can be gluing or vulcanization. In this embodiment, only one sealing gasket 8 is set between two adjacent curved plates 3, and the sealing gasket 8 is fixedly connected to one curved plate 3, that is, the sealing gasket 8 is fixedly set at one circumferential end of the curved plate 3, and not at the other end; in other embodiments, sealing gaskets 8 can also be set at both circumferential ends of the curved plate 3. See the attached Figure 2 When in use, the sealing gasket 8 is always in a compressed state, so after the two adjacent arc-shaped plates 3 move radially outward for a certain distance, see the attached Figure 3 , a gap appears between two adjacent arc-shaped plates 3, and the sealing gasket 8 can expand so that a good seal can be maintained between the two adjacent arc-shaped plates 3.

[0032] The curved plate 3 is arranged on the telescopic inner shield 2 along the radial guide. Specifically, the front end of the curved plate 3 is vertically provided with an inwardly folded flap 5, which is located in front of the telescopic inner shield 2. A guide long hole is opened on the flap 5, and a guide body is provided on the front end surface of the telescopic inner shield 2. The guide body has a guide portion that passes through the guide long hole and is fixedly connected to the telescopic inner shield 2, and a limiting portion fixed or integrally connected to the end of the guide portion away from the telescopic inner shield 2. The guide portion cooperates with the guide long hole. The limiting portion is located on the front side of the flap 5 and limits the flap 5 in the front and rear directions.

[0033] See attached Figure 4 The end of the arc plate 3 in the circumferential direction where the sealing gasket 8 is not provided is aligned with the flap 5, and the end where the sealing gasket 8 is provided is shorter than the flap 5, so as to leave space for providing the sealing gasket 8 between the two adjacent arc plates 3. A notch is provided on the flap 5 at the position corresponding to the sealing gasket 8 to facilitate the installation of the sealing gasket 8.

[0034] Specifically, the flap 5 is integrally connected to the arc-shaped plate 3 by welding, the guide body is a guide bolt, the rod of the guide bolt constitutes a guide portion and is threadedly connected to the telescopic inner shield 2, and the head of the guide bolt constitutes a limiting portion.

[0035] Under the action of the limiting structure, when the telescopic inner shield 2 and the telescopic outer shield 1 move axially relative to each other, the curved plate 3 will always move with the telescopic inner shield 2. The number of guide holes 6 on a flap 5 can be one, or for better guidance, the number of guide holes 6 can be two or more. In this case, the extension directions of the guide holes 6 on the same flap 5 are parallel. Regardless of the number of guide holes 6, only one guide hole 6 on a flap 5 has its extension direction perpendicular to the axis of the telescopic inner shield 2.

[0036] A first, annular sealing strip 9 is disposed between the curved plate 3 and the telescopic outer shield 1. The first sealing strip 9 is fixed to the curved plate 3 by gluing or vulcanization, and slides against the inner circumference of the telescopic outer shield 1. A second, annular sealing strip 10 is disposed between the curved plate 3 and the telescopic inner shield 2, providing a sealing seal with both the curved plate 3 and the telescopic inner shield 2. The first and second sealing strips 9, 10 can be sealing rings, a single strip of sealing material joined end-to-end to form a ring, or multiple strips of sealing material joined end-to-end to form a ring.

[0037] In order to improve the stability of the second sealing strip 10, a mounting groove can be provided on the curved plate 3 or the telescopic inner shield 2 to embed the second sealing strip 10. The provision of the mounting groove can also ensure that the gap between the curved plate 3 and the telescopic inner shield 2 is sufficiently small initially while ensuring that the second sealing strip 10 has a certain thickness.

[0038] The telescopic inner shield 2 is also provided with a pushing structure 11 for radially pushing the curved plate 3. The pushing structure 11 can specifically be a cylinder or an electric push rod. The pushing structure 11 is fixedly mounted on the inner side of the telescopic inner shield 2. The telescopic inner shield 2 is radially penetrated with a through-hole for the output end of the pushing structure 11 to pass through to push the curved plate 3. The position of the through-hole is opposite to the position of the first sealing strip 9, and the mounting groove is located behind the through-hole. After the telescopic output rod of the pushing structure 11 passes through the through-hole, it is fixedly connected to the corresponding curved plate 3 by means of a thread.

[0039] During initial use, both the first and second sealing strips 9, 10 are compressed. During use, the first sealing strip 9 continuously slides against the telescopic outer shield 1, causing wear and radial thinning of the first sealing strip 9. Once the first sealing strip 9 wears, the curved plate 3, propelled by the thrust structure 11, moves radially outward, further maintaining close contact between the first sealing strip 9 and the telescopic outer shield 1 and ensuring a good seal between them. As the curved plate 3 moves, the gap between the curved plate 3 and the telescopic inner shield 2 increases, during which the second sealing strip 10 expands to ensure a tight seal in the gap.

[0040] Compared with the existing technology, the double-shield TBM utilizes the arc plate 3 to transmit force between the jacking structure 11 and the first sealing strip 9. The arc plate 3 can uniformize the jacking force of the jacking structure 11, effectively improving the uniformity of force and sealing effect of the first sealing strip 9 in the circumferential direction.

[0041] The operator can loosen the limiting bolt 4 in the shield shell and directly pull out the arc plate 3 from between the telescopic outer shield 1 and the telescopic inner shield 2 to remove the first sealing strip 9, which effectively improves the convenience of replacing the first sealing strip 9.

[0042] In the above embodiment, the operator can remove the curved plate 3 by removing the guide bolts, making assembly and disassembly relatively convenient. In other embodiments, the guide bolts can be replaced with guide pins. These guide pins are interference-fitted into pin holes on the front end of the telescopic inner shield 2. A stop cap is fixed to the front end of the guide pins, which limits the forward and backward position of the flap 5. In this embodiment, the guide pins constitute the guide portion, and the guide caps constitute the stop portion. In other embodiments, the guide body can be welded to the front end of the telescopic inner shield 2, with the flap 5 and curved plate 3 fixedly connected by bolts, also facilitating removal of the curved plate 3.

[0043] In other embodiments, a guide stopper rod can be fixed radially inwardly of the curved plate 3. This rod and the curved plate 3 are threaded together, facilitating removal of the rod. A guide stopper hole is radially provided through the telescopic inner shield 2. The guide stopper rod is positioned within the hole and engages with it for guidance. Unscrewing the guide stopper rod allows removal of the curved plate 3.

[0044] Specific embodiment 2 of the double shield TBM provided by the utility model:

[0045] This embodiment is based on embodiment 1, and the difference from embodiment 1 is that, see attached Figure 1 The double-shield TBM in this embodiment also includes a cleaning nozzle 12. The cleaning nozzle 12 is a straight tube. The nozzle of the cleaning nozzle 12 is opened on the axial end face of the ejection end of the cleaning nozzle 12. In this embodiment, a through hole for the cleaning nozzle 12 to pass from the inside to the outside is opened on the telescopic inner shield 2. After passing through the through hole, the cleaning nozzle 12 passes through the corresponding curved plate 3 and is fixedly installed on the corresponding curved plate 3. The fixing form can be interference fit or thread. The cleaning nozzle 12 is loosely matched with the through hole on the telescopic inner sleeve. One cleaning nozzle 12 is correspondingly installed on each curved plate 3.

[0046] The cleaning nozzles 12 can eject air or water to flush the annular gap 7, preventing excessive accumulation of rock debris within the annular gap 7. The cleaning nozzles 12 are spaced apart along the circumference of the annular gap 7. To enable the cleaning nozzles 12 to clean a wider area within the annular gap 7, the cleaning nozzles 12 can be tilted, with the ejection ends of the cleaning nozzles 12 tilted toward the circumference of the annular gap 7. This allows the ejected air or water to be directed toward the circumference of the annular gap 7. To enable the cleaning nozzles 12 to eject air or water backward, thereby increasing the backward flushing capability, the ejection ends of the cleaning nozzles 12 can also be tilted backward.

[0047] The cleaning nozzle 12 needs to move with the curved plate 3 , and the gap between the cleaning nozzle 12 and the through hole can be designed according to the moving distance to prevent interference.

[0048] In this embodiment, the installation groove for installing the second sealing strip 10 is located behind the through hole.

[0049] Specific embodiment 3 of the double shield TBM provided by the utility model:

[0050] This embodiment is based on Example 2, and differs from Example 2 in that the end face of the ejection end of the cleaning nozzle in this embodiment is closed, and the cleaning nozzle has a nozzle on the circumferential wall of the ejection end, and the nozzle faces rearward or toward the tangent direction of the outer circumferential surface of the arc plate.

[0051] Specific embodiment 4 of the double shield TBM provided by the utility model:

[0052] This embodiment is based on Example 2, and differs from Example 2 in that the cleaning nozzle in this embodiment is not a straight pipe. The cleaning nozzle in this embodiment includes a straight pipe section and a bent section located at one axial end of the straight pipe section. The nozzle of the cleaning nozzle is arranged on the end face of the bent section, and the axis of the through hole and the straight pipe section intersects perpendicularly with the axis of the telescopic inner shield. In this embodiment, the bent section of the cleaning nozzle is bent backward so that the ejected air flow or water flow can be directed backward.

[0053] In other implementations of this embodiment, the bent section of the cleaning nozzle may also be bent in the tangential direction of the outer peripheral surface of the arc-shaped plate.

[0054] Specific embodiment 5 of the double shield TBM provided by the utility model:

[0055] This embodiment is based on embodiment 1 or 2 or 3 or 4, except that, see attached Figure 1 The double shield TBM in this embodiment also includes multiple oil filling pipes 13, which are installed on the telescopic inner shield 2. The oil filling ends of the oil filling pipes 13 are located in the annular gap 7 and directly in front of the first sealing strip 9.

[0056] The oil filling pipe 13 can be used to replenish lubricating grease to the first sealing strip 9 , thereby reducing friction between the first sealing strip 9 and the telescopic outer shield 1 , reducing the wear rate, and increasing the service life of the first sealing strip 9 .

[0057] Specific embodiment 6 of the double shield TBM provided by the utility model:

[0058] This embodiment is based on embodiment 1, and the difference from embodiment 1 is that, see attached Figure 5 The double shield TBM in this embodiment further includes a detection device 14 and a controller 15, see the attached Figure 1 The detection device 14 is fixedly mounted on the inner circumference of the telescopic outer shield 1 and is located in front of the first sealing strip 9. The detection device 14 can be used to detect the thickness of the first sealing strip 9. The detection device 14 can be specifically a camera.

[0059] The controller 15 is electrically connected to the detection device 14, and the controller 15 is also electrically connected to the pushing structure 11. The detection device 14 transmits the detected signal to the controller 15. The controller 15 can obtain the thickness information of the first sealing strip 9 through analysis and calculation. After the first sealing strip 9 is thinned to a set value, the controller 15 controls the pushing structure 11 to push the curved plate 3; after the first sealing strip 9 is thinned to another set value, the controller 15 controls the pushing structure 11 to push the curved plate 3 again.

[0060] In other embodiments, the double-shield TBM may further include the cleaning nozzle 12 of Example 2, 3, or 4 and the oil injection pipe 13 of Example 5. In this case, the controller 15 may further be electrically connected to the pumps corresponding to the cleaning nozzle 12 and the oil injection pipe 13 to automatically control the cleaning operation or oil injection operation of the cleaning nozzle 12 and the oil injection pipe 13. The cleaning operation and the oil injection operation may be performed at regular intervals.

[0061] Specific embodiment 7 of the double shield TBM provided by the present invention:

[0062] This embodiment is based on Example 1, and differs from Example 1 in that the pushing structure in this embodiment is a spring, and the outer circumference of the telescopic inner shield is provided with an annular embedding groove for installing the spring, and the two ends of the spring respectively press against the bottom wall of the embedding groove and the inner circumference of the arc plate.

[0063] Specific embodiment 8 of the double shield TBM provided by the utility model:

[0064] This embodiment is based on Example 1 and differs from Example 1 in that, in this embodiment, an embedding groove is provided on the outer circumferential surface of the telescopic inner shield, the arcuate plate is installed in the embedding groove, the radial inner side of the first sealing strip is fixedly connected to the arcuate plate, and the radial outer side is still slidably engaged with the inner circumferential surface of the telescopic outer shield, and the radial inner side of the first sealing strip is also located in the embedding groove.

[0065] In this way, the first sealing strip completely fills the annular gap, so there is no need to provide a second sealing strip, and no sealing gaskets are needed between adjacent arc-shaped plates.

[0066] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments without inventive effort, or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A double shield TBM, characterized by: The double-shield TBM comprises a telescopic outer shield and a telescopic inner shield, an annular gap being formed between the inner circumference of the telescopic outer shield and the outer circumference of the telescopic inner shield, an integral annular first sealing strip or at least two first sealing strips forming an annular shape being provided in the annular gap, the first sealing strip being in sliding sealing cooperation with the inner circumference of the telescopic outer shield, at least two arc-shaped plates forming an annular shape being provided on the inner side of the first sealing strip, the arc-shaped plates being fixedly connected to the first sealing strips, and being radially guided and arranged on the telescopic inner shield, the double-shield TBM further comprises a pushing structure for radially pushing the arc-shaped plates outward after the first sealing strips are worn.

2. The double shield TBM according to claim 1, characterized in that: A second sealing strip is provided between the arc plate and the outer circumference of the telescopic inner shield. The pushing structure comprises a telescopic output rod, the end of which radially penetrates the telescopic inner shield and is fixedly connected to the arc plate.

3. The double shield TBM according to claim 1 or 2, characterized in that: One end of the double-shield TBM excavation faces forward, and a flap is vertically provided at the front end of the arc-shaped plate. The flap is located in front of the telescopic inner shield. A radially extending guide long hole is opened on the flap, and a guide body is provided on the front end surface of the telescopic inner shield. The guide body has a guide part that passes through the guide long hole and is fixedly connected to the telescopic inner shield, and a limiting part that is fixed or integrally connected to the front end of the guide part. The guide part cooperates with the guide long hole. The limiting part is located on the front side of the flap and limits the forward movement of the flap.

4. The double shield TBM according to claim 3, characterized in that: The guide body is a guide bolt, the rod of the guide bolt constitutes a guide part and is threadedly connected with the telescopic inner shield, and the head of the guide bolt constitutes a limiting part.

5. The double shield TBM according to claim 1 or 2, characterized in that: A sealing gasket is provided between the circumferential end surfaces of two circumferentially adjacent arc-shaped plates, and the sealing gasket is fixedly connected to one of the arc-shaped plates.

6. The double shield TBM according to claim 1 or 2, characterized in that: One end of the double-shield TBM excavation faces forward, and the double-shield TBM also includes a plurality of cleaning nozzles for spraying water or air. The spraying ends of the cleaning nozzles are located between the curved plate and the telescopic outer shield and the spraying ends are behind the first sealing strip.

7. The double shield TBM according to claim 6, characterized in that: The cleaning nozzle is a straight pipe, the nozzle of the cleaning nozzle is arranged on the axial end face of the ejection end of the cleaning nozzle, and the ejection end of the cleaning nozzle is tilted backward so that the airflow or water flow ejected by the cleaning nozzle flows tilted backward.

8. The double shield TBM according to claim 6, characterized in that: The cleaning nozzle includes a straight pipe section and a bent section located at one end of the straight pipe section. The axis of the straight pipe section of the cleaning nozzle intersects the axis of the telescopic inner shield at right angles. The nozzle of the cleaning nozzle is arranged on the end face of the bent section, and the bent section bends backward or in the tangential direction of the outer peripheral surface of the curved plate; or the cleaning nozzle is a straight pipe, and the end face of one end of the cleaning nozzle extending between the curved plate and the telescopic outer shield is closed, and the nozzle for spraying water or air is opened on the circumferential surface of the spraying end, and the nozzle faces backward or in the tangential direction of the outer peripheral surface of the curved plate.

9. The double shield TBM according to claim 1 or 2, characterized in that: One end of the double-shield TBM excavation faces forward. The double-shield TBM also includes an oil injection pipe, which is installed on the telescopic inner shield. The oil injection end of the oil injection pipe is located in the annular gap and in front of the first sealing strip.

10. The double shield TBM according to claim 1 or 2, characterized in that: A detection device is fixedly installed on the inner side of the telescopic outer shield. The detection device is located in front of the first sealing strip and is used to detect the thickness of the first sealing strip. The double-shield TBM also includes a controller that receives signals from the detection device and issues action instructions to the pushing structure.

Images