Shield apparatus and variable diameter tunnel construction method

Abstract

The present disclosure relates to a shield device and a variable-diameter tunnel construction method. The shield device comprises: a variable-diameter shield body assembly having a first shield body and a second shield body, the first shield body being used for supporting a first diameter tunnel, the second shield body being used for supporting a second diameter tunnel and being capable of being mounted on or separated from an outer periphery of the first shield body, wherein a diameter of the first shield body is smaller than a diameter of the second shield body; and a variable-diameter cutter head assembly rotatably arranged at a front side of the variable-diameter shield body assembly and having a first cutter head and a cutter head outer ring, the first cutter head being used for tunneling of the first diameter tunnel, the cutter head outer ring being capable of being mounted on an outer periphery of the first cutter head to jointly form a second cutter head with the first cutter head or being separated from the first cutter head, wherein the second cutter head is used for tunneling of the second diameter tunnel; wherein a maximum diameter of the first cutter head is smaller than a maximum diameter of the second cutter head, and a diameter of the first diameter tunnel is smaller than a diameter of the second diameter tunnel.

Description

Technical Field

[0001] This disclosure relates to the field of tunnel construction, and in particular to a shield tunneling device and a method for constructing variable-diameter tunnels. Background Technology

[0002] Currently, station excavation generally employs mining methods, using manual or mechanical excavation (open-cut / cut-and-cover). This process consumes significant ground resources (roads / facilities), disrupting normal urban traffic. Furthermore, station excavation typically cannot proceed continuously with the mainline tunnel excavation using the shield tunneling method, which to some extent restricts the project's progress and impacts construction efficiency.

[0003] Some related technologies have proposed using variable-diameter tunnel boring machines (TBMs) for station construction. However, the lack of mature variable-diameter TBMs often results in drawbacks such as complex structures and narrow applicability. Summary of the Invention

[0004] In view of this, the present disclosure provides a shield tunneling device and a variable diameter tunnel construction method, which can improve the tunnel construction process.

[0005] In one aspect of this disclosure, a tunnel boring machine is provided, comprising:

[0006] A variable-diameter shield assembly has a first shield and a second shield, the first shield being used for supporting a tunnel of a first diameter, and the second shield being used for supporting a tunnel of a second diameter, and is capable of being mounted on the outer periphery of the first shield or detached from the first shield, wherein the diameter of the first shield is smaller than the diameter of the second shield; and

[0007] A variable diameter cutterhead assembly is rotatably disposed on the front side of the variable diameter shield assembly and has a first cutterhead and a cutterhead outer ring. The first cutterhead is used for excavating a tunnel of the first diameter, and the cutterhead outer ring can be mounted on the outer periphery of the first cutterhead to form a second cutterhead together with the first cutterhead or to be separated from the first cutterhead. The second cutterhead is used for excavating a tunnel of the second diameter.

[0008] Wherein, the maximum diameter of the first cutter head is smaller than the maximum diameter of the second cutter head, and the diameter of the first diameter tunnel is smaller than the diameter of the second diameter tunnel.

[0009] In some embodiments, the outer ring of the cutter head is mounted or detached from the first cutter head via a cutter head connecting ring.

[0010] In some embodiments, the outer ring of the cutter head includes a ring body and a plurality of second tool holders, the plurality of second tool holders being arranged at intervals on the ring body along the circumference of the outer ring of the cutter head.

[0011] In some embodiments, the first cutter head includes a cutter head body and a plurality of first tool holders, the plurality of first tool holders being arranged at intervals on the cutter head body along the circumference of the first cutter head.

[0012] In some embodiments, in the second cutter disc formed by the outer ring of the cutter disc and the first cutter disc, the plurality of first cutter holders and the plurality of second cutter holders correspond one-to-one in the circumferential direction and are respectively aligned in the radial direction.

[0013] In some embodiments, the tunnel boring machine further includes:

[0014] The cutterhead drive mechanism is located inside the variable diameter shield assembly and is connected to the first cutterhead drive, and is configured to drive the first cutterhead to rotate.

[0015] In some embodiments, the second shield body is a double-shell structure, the double-shell structure comprising: an annular outer sleeve and an annular inner sleeve, the annular inner sleeve being detachable relative to the annular outer sleeve.

[0016] In some embodiments, the second shield body is configured to be securely and sealed to the outer periphery of the first shield body via a first connecting mechanism when it is installed onto the outer periphery of the first shield body.

[0017] In some embodiments, the second shield body is configured to be reinforcedly and fixedly connected to the outer periphery of the first shield body via a second connecting mechanism when it is installed onto the outer periphery of the first shield body.

[0018] In some embodiments, the tunnel boring machine further includes:

[0019] The main beam is installed inside the first shield body and connected to the first shield body;

[0020] The first propulsion mechanism is mounted on the first shield body and is configured to propel the first shield body for tunneling.

[0021] A second propulsion mechanism, mounted on the second shield body, is configured to propel the second shield body for tunneling; and

[0022] A segment assembly mechanism, mounted on the main beam, is configured to assemble segments within a tunnel of the first diameter or a tunnel of the second diameter.

[0023] In some embodiments, at least one of the first propulsion mechanism and the second propulsion mechanism includes:

[0024] Multiple propulsion cylinders are arranged at intervals along the circumference.

[0025] In some embodiments, the tunnel boring machine further includes:

[0026] The shield body cutting ring has multiple fan-shaped segments, which can be assembled into a ring;

[0027] The plurality of fan-shaped segments are configured to be centrally fixedly installed on the end of the second shield body near the outer ring of the cutterhead during the excavation of the tunnel of the second diameter, and after the second shield body is separated from the first shield body, they are assembled into a ring and fixedly connected to the end of the first shield body near the outer ring of the cutterhead.

[0028] In one aspect of this disclosure, a method for constructing a variable-diameter tunnel based on the aforementioned shield tunneling equipment is provided, comprising:

[0029] The second cutterhead is used to excavate a tunnel of the second diameter, and the second shield body is used for tunnel support and segment assembly.

[0030] After tunneling to the preset position for diameter change, the shield tunneling equipment is moved away from the tunnel face by a preset displacement;

[0031] Separate the outer ring of the cutterhead from the first cutterhead, and separate at least a portion of the second shield from the first shield;

[0032] Using at least a portion of the second shield as the starting guide platform for the first shield, the tunnel of the first diameter is excavated through the first cutterhead, and the tunnel is supported by the first shield.

[0033] In some embodiments, the variable-diameter tunnel construction method further includes:

[0034] Before tunneling to the predetermined position for diameter change, the strata are reinforced.

[0035] In some embodiments, the step of moving the tunnel boring machine away from the working face by a predetermined displacement includes:

[0036] A jacking cylinder is installed on the front side of the tunnel boring machine, and one end of the jacking cylinder is placed against the tunnel face.

[0037] The jacking action of the jacking cylinder causes the tunnel boring machine to move away from the working face until it reaches a preset displacement position away from the working face.

[0038] In some embodiments, prior to the step of displacing the tunnel boring machine relative to the tunnel face by a predetermined displacement, the variable diameter tunnel construction method further includes:

[0039] The working face is subjected to local processing.

[0040] In some embodiments, prior to the step of moving the tunnel boring machine away from the working face by a predetermined displacement, the method further includes:

[0041] The rear supporting mechanism of the tunnel boring machine is disengaged from the main beam, and the entry channel inside the tunnel boring machine is opened.

[0042] In some embodiments, after at least a portion of the second shield body is separated from the first shield body, the variable-diameter tunnel construction method further includes:

[0043] The tail shield of the first shield body is fixedly connected to the rear end of the middle shield of the first shield body, and the rear supporting mechanism of the shield tunneling equipment is connected to the main beam.

[0044] In some embodiments, the step of separating at least a portion of the second shield from the first shield includes:

[0045] This separates the front and middle shields of the second shield from the first shield.

[0046] In some embodiments, the step of separating at least a portion of the second shield from the first shield further includes:

[0047] A movable or adjustable fixed-position retaining ring is provided on the inner ring of the second shield body. The retaining ring provides a reaction force to the first shield body to move forward, so that the tunnel boring machine can advance a preset distance through the first cutterhead and the first shield body.

[0048] In some embodiments, the variable-diameter tunnel construction method further includes:

[0049] Before at least a portion of the second shield body separates from the first shield body, multiple fan-shaped segments of the shield body cutting ring are assembled into a ring and fixedly connected to the end of the first shield body adjacent to the outer ring of the cutterhead.

[0050] In some embodiments, after at least a portion of the second shield body is separated from the first shield body, the variable-diameter tunnel construction method further includes:

[0051] This separates the inner shell of the annular sleeve from the outer shell of the annular sleeve of the second shield body.

[0052] In some embodiments, after the tail shield of the first shield body is fixedly connected to the rear end of the middle shield of the first shield body and the rear supporting mechanism of the shield tunneling equipment is connected to the main beam, the variable diameter tunnel construction method further includes:

[0053] The segment assembly mechanism is adjusted from assembling the second diameter tunnel segment to assembling the first diameter tunnel segment, and at least one ring of the first diameter tunnel segment is pushed backward onto the reaction base installed on the second diameter tunnel segment by the first propulsion mechanism on the first shield body.

[0054] In some embodiments, the variable-diameter tunnel construction method further includes:

[0055] A reaction base is fixedly installed on the second diameter tunnel segment so that the tunnel boring machine can excavate the first diameter tunnel and assemble the segments through the reaction base.

[0056] In some embodiments, the variable-diameter tunnel construction method further includes:

[0057] After the tunnel boring machine passes through the reinforced geological area, grouting is performed behind the spliced ​​first diameter tunnel segment wall.

[0058] In some embodiments, the variable-diameter tunnel construction method further includes:

[0059] After the outer ring of the cutterhead is separated from the first cutterhead, the outer ring of the cutterhead is fixedly connected to the second shield body through the rib plate to form the launching guide platform of the first shield body.

[0060] Based on the embodiments of this disclosure, the conversion between variable diameter cutterhead assembly and variable diameter shield assembly is used to realize the excavation and support of tunnels with different diameters. The conversion process is simple and quick, reduces equipment costs, enables large-scale excavation stroke, and realizes mechanized excavation technology for station construction and various types of underground excavation projects in urban underground spaces with similar complex environments. Attached Figure Description

[0061] The accompanying drawings, which form part of this specification, illustrate embodiments of this disclosure and, together with the specification, serve to explain the principles of this disclosure.

[0062] This disclosure will become clearer with reference to the accompanying drawings and the following detailed description, wherein:

[0063] Figure 1 This is a schematic diagram of a shield tunneling device embodiment excavating a tunnel of a second diameter.

[0064] Figure 2 (a)-(c) are schematic diagrams of the structure of the first cutterhead, the outer ring of the cutterhead, and the variable diameter cutterhead assembly in the embodiments of the shield tunneling equipment disclosed herein;

[0065] Figure 3 This is a schematic diagram of the shield tunneling equipment embodiment disclosed herein after it has moved away from the working face at a predetermined distance and the rear supporting mechanism has disengaged;

[0066] Figure 4 This is a schematic diagram illustrating how the shield tunneling equipment embodiment of this disclosure provides a reaction force to the first shield body via a retaining ring;

[0067] Figure 5 yes Figure 4 An enlarged view of the area indicated by circle A in the middle.

[0068] Figure 6This is a schematic diagram of an embodiment of the shield tunneling equipment disclosed herein, in which a retaining ring with adjustable positions provides a reaction force to the first shield body, so that the shield tunneling equipment can advance a preset distance through the first cutterhead and the first shield body;

[0069] Figure 7 This is a schematic diagram of a portion of the shield block of the second shield body supporting the first shield body in an embodiment of the shield tunneling equipment disclosed herein;

[0070] Figure 8 This is a schematic diagram of the removal of the annular sleeve inner shell of the second shield body in an embodiment of the shield tunneling equipment disclosed herein;

[0071] Figure 9 This is a schematic diagram of the shield tunneling equipment embodiment disclosed herein, in which the assembled multi-ring segments are pushed toward the reaction base after the tail shield is installed at the tail end of the middle shield of the first shield body;

[0072] Figure 10 This is a schematic diagram of an embodiment of the shield tunneling equipment disclosed herein, showing the excavation of a first-diameter tunnel and the filling of mortar between the multi-ring segments and the inner wall of a second-diameter tunnel;

[0073] Figure 11 This is a schematic flowchart illustrating an embodiment of the variable-diameter tunnel construction method using the shield tunneling equipment disclosed herein.

[0074] It should be understood that the dimensions of the various parts shown in the accompanying drawings are not drawn to actual scale. Furthermore, the same or similar reference numerals denote the same or similar components.

[0075] Explanation of reference numerals in the attached figures:

[0076] 1-Variable diameter cutter head assembly, 11-First cutter head, 111-Cutter head body, 112-First tool holder, 12-Outer ring of cutter head, 121-Ring body, 122-Second tool holder, 123-Rib plate, 13-Cutter head connecting ring;

[0077] 2-Variable diameter shield assembly, 21-First shield, 211-Front shield of first shield 21, 212-Middle shield of first shield 21, 213-Tail shield of first shield 21, 22-Second shield, 221-Annular sleeve outer shell, 222-Annular sleeve inner shell, 22a-Front shield of second shield 22, 22b-Middle shield of second shield 22, 22c-Tail shield of second shield 22, 23-First connecting mechanism, 24-Second connecting mechanism, 25-Shield cutting ring;

[0078] 3- Cutter head drive mechanism;

[0079] 41-Main beam, 42-First propulsion mechanism, 43-Second propulsion mechanism;

[0080] 51 - Segment assembly mechanism; 52 - Supporting mechanism;

[0081] 6-Push cylinder;

[0082] 71-Retaining ring, 72-Reaction base;

[0083] HF - tunnel face, T1 - first diameter tunnel, T2 - second diameter tunnel, S1 - first diameter tunnel segment, S2 - second diameter tunnel segment, S3 - grouting zone. Detailed Implementation

[0084] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the present disclosure or its application or use. The present disclosure may be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that the present disclosure will be thorough and complete, and will fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless specifically stated otherwise, the relative arrangement of components and steps, the composition of materials, numerical expressions, and values ​​set forth in these embodiments should be interpreted as exemplary only and not as limiting.

[0085] The terms "first," "second," and similar words used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as "including" or "contains" mean that the element preceding the word encompasses the element listed after it, and do not exclude the possibility of encompassing other elements as well. Terms such as "above," "below," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, this relative positional relationship may also change accordingly.

[0086] In this disclosure, when a specific device is described as being located between a first device and a second device, an intermediary device may or may not be present between the specific device and the first or second device. When a specific device is described as being connected to other devices, the specific device may be directly connected to the other devices without an intermediary device, or it may be not directly connected to the other devices but have an intermediary device.

[0087] All terms used in this disclosure (including technical or scientific terms) have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in a general dictionary, such as a dictionary, should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or highly formalized meaning, unless expressly defined herein.

[0088] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0089] In response to the problems of low mechanization level, low overall construction efficiency, shortage of public resources, and poor environmental friendliness in the relevant technologies of station construction methods (open-cut / cut-and-cover), this disclosure proposes a construction process that can realize the conversion of large-diameter tunnel excavation into small-diameter tunnel excavation, realize safe and efficient shield tunneling station excavation technology, and simultaneously meet the needs of continuous excavation of station and main line tunnels, improve overall construction efficiency, and reduce construction costs.

[0090] Figure 1 This is a schematic diagram of a shield tunneling device embodiment of the present disclosure excavating a tunnel of the second diameter. Figure 2 (a)-(c) are schematic diagrams of the structure of the first cutterhead, the outer ring of the cutterhead, and the variable diameter cutterhead assembly in the embodiments of the shield tunneling equipment disclosed herein.

[0091] refer to Figure 1 and Figure 2 This disclosure provides a tunnel boring machine (TBM) including a variable-diameter shield assembly 2 and a variable-diameter cutterhead assembly 1. The variable-diameter shield assembly 2 has a first shield 21 and a second shield 22. The first shield 21 is used for supporting a tunnel T1 with a first diameter, and the second shield 22 is used for supporting a tunnel T2 with a second diameter. The shield 22 can be installed on the outer periphery of the first shield 21 or separated from the first shield 21, wherein the diameter of the first shield 21 is smaller than the diameter of the second shield 22.

[0092] The variable diameter cutterhead assembly 1 is rotatably disposed on the front side of the variable diameter shield assembly 2, and has a first cutterhead 11 and a cutterhead outer ring 12. The first cutterhead 11 is used for excavating the first diameter tunnel T1, and the cutterhead outer ring 12 can be installed on the outer periphery of the first cutterhead 11 to form a second cutterhead together with the first cutterhead 11 or to be separated from the first cutterhead 11. The second cutterhead is used for excavating the second diameter tunnel T2.

[0093] The maximum diameter of the first cutter head 11 is smaller than the maximum diameter of the second cutter head, and the diameter of the first diameter tunnel T1 is smaller than the diameter of the second diameter tunnel T2.

[0094] In the above embodiments, some key components of the tunnel boring machine (cutterhead, shield body, cutterhead drive mechanism, segment assembly mechanism, etc.) can achieve greater versatility and can simultaneously meet the tunneling requirements of two modes: sub-shield (i.e., to achieve the excavation, support and segment assembly of the first diameter tunnel) and mother shield (i.e., to achieve the excavation, support and segment assembly of the second diameter tunnel). The equipment cost is low and the conversion process is simple and quick.

[0095] This disclosure enables the development of a variable-diameter tunnel boring machine with a large-scale excavation stroke and its construction scheme. This variable-diameter tunnel boring machine facilitates mechanized excavation technology for railway station construction and various types of underground excavation projects in urban environments with similar complex conditions. In some embodiments, the tunnel boring machine can be a concentric dual-mode mother-daughter tunnel boring machine.

[0096] refer to Figure 2 In embodiments (a), (b), and (c), the outer ring 12 of the cutterhead is mounted or detached from the first cutterhead 11 via a cutterhead connecting ring 13. The cutterhead connecting ring 13 may be integrally formed with the first cutterhead 11, or it may be installed between the first cutterhead 11 and the outer ring 12 during installation. The cutterhead connecting ring 13 can transmit the torque from the first cutterhead 11 to the outer ring 12, enabling the outer ring 12 to stably cut the rock strata.

[0097] To ensure stable and reliable tunneling of the variable diameter cutterhead assembly 1 during the excavation of both the first diameter tunnel T1 and the second diameter tunnel T2, refer to Figure 2 (b) In some embodiments, the cutter head outer ring 12 includes a ring body 121 and a plurality of sets of second cutter holders 122, the plurality of sets of second cutter holders 122 being spaced apart on the ring body 121 along the circumference of the cutter head outer ring 12, so as to apply a relatively uniform cutting force to the work surface. Accordingly, refer to Figure 2 (a) The first cutter head 11 may also include a cutter head body 111 and a plurality of first cutter holders 112, the plurality of first cutter holders 112 being arranged at intervals on the cutter head body 111 along the circumference of the first cutter head 11.

[0098] refer to Figure 2 (c) In the second cutter disc formed by the outer ring 12 of the cutter disc and the first cutter disc 11, the plurality of first cutter holders 112 and the plurality of second cutter holders 122 correspond one-to-one in the circumferential direction and are respectively aligned in the radial direction.

[0099] refer to Figure 1 In some embodiments, the tunnel boring machine may further include a cutterhead drive mechanism 3. The cutterhead drive mechanism 3 is disposed within the variable diameter shield assembly 2 and is drivenly connected to the first cutterhead 11, configured to drive the first cutterhead 11 to rotate. When the outer ring 12 of the cutterhead is mounted on the outer periphery of the first cutterhead 11, the cutterhead drive mechanism 3 drives the rotation of the first cutterhead 11, thereby causing the outer ring 12 to rotate, thus cutting a larger diameter construction surface.

[0100] exist Figure 1The tunnel boring machine (TBM) may further include: a main beam 41, a first propulsion mechanism 42, a second propulsion mechanism 43, and a segment assembly mechanism 51. The main beam 41 is disposed within and connected to the first shield body 21. The first propulsion mechanism 42 is disposed on the first shield body 21 and configured to propel the first shield body 21 for tunneling. The second propulsion mechanism 43 is disposed on the second shield body 22 and configured to propel the second shield body 22 for tunneling. The segment assembly mechanism 51 is disposed on the main beam 41 and configured to assemble tunnel segments within the first diameter tunnel T1 or the second diameter tunnel T2.

[0101] By installing a first propulsion mechanism and a second propulsion mechanism in the first and second shield bodies respectively, the tunnel boring machine can quickly switch between tunneling with different diameters. Furthermore, the first propulsion mechanism can perform specific technological actions during the switching process, such as adjusting the position of the first shield body and pushing the tunnel segments backward to the reaction base.

[0102] Structurally, at least one of the first propulsion mechanism 42 and the second propulsion mechanism 43 may include a plurality of propulsion cylinders arranged at circumferential intervals. By controlling the propulsion force of the plurality of propulsion cylinders, the tunneling posture of the tunnel boring machine can be adjusted and the tunneling process can be stabilized.

[0103] exist Figure 1 In the process of tunneling, when the tunnel boring machine (TBM) is excavating the second diameter tunnel T2 through the second cutterhead and performing tunnel support and segment assembly through the second shield body 22, the first shield body 21 located inside the second shield body 22 includes a front shield 211 and a middle shield 212. At this time, the first shield body 21 also includes a tail shield 213. The second shield body 22 includes a front shield 22a, a middle shield 22b, and a tail shield 22c.

[0104] Figure 3 This is a schematic diagram of the shield tunneling equipment embodiment disclosed herein after it has moved away from the tunnel face at a predetermined distance and the rear supporting mechanism has disengaged. Figure 4 This is a schematic diagram of a shield tunneling device embodiment that provides a reaction force to the first shield body through a retaining ring. Figure 5 yes Figure 4 An enlarged view of the area indicated by circle A in the middle.

[0105] refer to Figure 3 In some embodiments, the tunnel boring machine may also include a jacking cylinder 6, which, through the jacking action of the jacking cylinder 6, causes the tunnel boring machine to move away from the face HF at a preset displacement when the diameter is changed, thereby obtaining space for disassembling or installing the variable diameter cutterhead assembly 1.

[0106] refer to Figure 1 and Figure 3In some embodiments, the tunnel boring machine (TBM) may also include a rear support mechanism 52. The rear support mechanism 52 may include a group of equipment supporting the TBM's hydraulic control, electrical control, cooling, lubrication, and other functions. The rear support mechanism 52 can be disconnected from the main beam 41 as needed to facilitate diameter change operations. Furthermore, the TBM may also include a muck conveying mechanism (e.g., a screw conveyor) and a slurry circulation system (e.g., slurry inlet and outlet pipelines, pumps, valve groups, etc.). In this embodiment, the cutterhead drive mechanism, segment assembly mechanism, screw conveyor, rear support mechanism, and slurry circulation system do not require modification to meet the construction requirements of both mother-daughter shield tunneling modes.

[0107] refer to Figure 4 and Figure 5 In some embodiments, the tunnel boring machine further includes a shield cutting ring 25. The shield cutting ring 25 has multiple fan-shaped segments that can be assembled into a ring. For ease of understanding, during the excavation of the second diameter tunnel T2, the multiple fan-shaped segments (…) are pre-assembled… Figure 5 The solid line portion (as indicated by 25) is centrally fixedly disposed on the end of the second shield body 22 adjacent to the outer ring 12 of the cutterhead. For example, multiple fan ring segments are overlapped and welded or fixed to the inner side of the front shield 22a of the second shield body 22 by bolts.

[0108] After separating the second shield body 22 from the first shield body 21, multiple fan-shaped segments are assembled into a ring. Figure 5 The section indicated by the dotted line in section 25) is fixedly connected to the end of the first shield 21 near the outer ring 12 of the cutterhead. The operator can directly remove multiple fan-shaped ring segments from the inner side of the front shield 22a of the second shield 22, weld them into a ring, and weld them to the end of the first shield 21 near the outer ring 12 of the cutterhead. This eliminates the need to transport the material forming the cutting ring from the rear to the front of the tunnel boring machine, greatly improving construction convenience and efficiency.

[0109] refer to Figure 5 In some embodiments, the second shield 22 is configured to be securely and sealingly connected to the outer periphery of the first shield 21 via a first connecting mechanism 23 (e.g., circumferential fasteners and circumferential seals) when mounted onto the outer periphery of the first shield 21. Figure 5 In this process, when the second shield body 22 is installed on the outer periphery of the first shield body 21, it can be reinforced and fixedly connected to the outer periphery of the first shield body 21 through the second connecting mechanism 24 (such as a reinforcing rib).

[0110] Figure 6 This is a schematic diagram illustrating how, in an embodiment of the shield tunneling equipment disclosed herein, adjustable retaining rings at multiple positions provide reaction force to the first shield body, enabling the shield tunneling equipment to advance a predetermined distance through the first cutterhead and the first shield body. (Reference) Figure 4 and Figure 6 In some embodiments, the tunnel boring machine may further include a retaining ring 71. The fixed position of the retaining ring 71 within the inner ring of the second shield body 22 is movable or adjustable. The retaining ring 71 can provide a reaction force to the first shield body 21 during diameter changes, enabling the tunnel boring machine to advance a predetermined distance through the first cutterhead 11 and the first shield body 21. Multiple retaining rings 71 may be provided, spaced apart axially, or a single retaining ring 71 may be provided, with its position adjustable axially.

[0111] Figure 7 This is a schematic diagram showing a portion of the shield block of the second shield body supporting the first shield body in an embodiment of the shield tunneling equipment disclosed herein. (Reference) Figure 7 In some embodiments, the second shield may include multiple shield blocks, wherein a portion of the shield blocks located below the first shield (i.e., the bottom block) can support the first shield and serve as the launching platform for the first shield, utilizing a propulsion mechanism to achieve the rapid shell-switching of the first shield relative to the second shield.

[0112] Figure 8 This is a schematic diagram of the removal of the annular sleeve inner shell of the second shield body in an embodiment of the shield tunneling equipment disclosed herein. Figure 9 This is a schematic diagram of an embodiment of the shield tunneling equipment disclosed herein, in which the assembled multi-ring segments are pushed toward the reaction base after the tail shield is installed at the tail end of the middle shield of the first shield body. Figure 10 This is a schematic diagram of an embodiment of the shield tunneling equipment disclosed herein, showing the excavation of a first-diameter tunnel and the filling of mortar between the multi-ring segments and the inner wall of a second-diameter tunnel.

[0113] refer to Figures 8-10 In some embodiments, to save equipment costs, the second shield body 22 has a double-shell structure. The double-shell structure includes an annular outer sleeve 221 and an annular inner sleeve 222, the inner sleeve 222 being detachable from the outer sleeve 221. This allows the inner sleeve 222 to be removed and reused after the outer sleeve 221 and inner sleeve 222 are separated, saving equipment costs. The outer sleeve 221 can remain in the soil to provide support.

[0114] In this embodiment, the disassembly and assembly of relevant components involved in the shield tunneling equipment during the shell conversion process can be considered in advance, and a convenient and feasible operation procedure can be formulated, which has promotional value.

[0115] Figure 11 This is a schematic flowchart illustrating an embodiment of the variable-diameter tunnel construction method using the shield tunneling equipment disclosed herein. Refer to the aforementioned embodiments of the shield tunneling equipment, and further refer to... Figures 1 to 11 This disclosure also provides a method for constructing a variable-diameter tunnel, including steps S1 to S4.

[0116] In step S1, the second diameter tunnel T2 is excavated by the second cutterhead, and tunnel support and segment assembly are carried out by the second shield 22.

[0117] In step S2, after tunneling to the preset position for diameter change, the shield tunneling equipment is moved away from the face HF by a preset displacement.

[0118] In step S3, the outer ring 12 of the cutter head is separated from the first cutter head 11, and at least a portion of the second shield body 22 is separated from the first shield body 21.

[0119] In step S4, at least a portion of the second shield 22 is used as the starting guide of the first shield 21, and the first diameter tunnel T1 is excavated through the first cutterhead 11, and the tunnel is supported by the first shield 21.

[0120] This embodiment enables the switching process from a larger diameter tunnel to a smaller diameter tunnel. During the switching process, the variable diameter shield assembly and the variable diameter cutterhead assembly are used to process the shield and cutterhead respectively to achieve the diameter change. At least part of the second shield (e.g., multiple shield blocks at the bottom) is used as a starting guide to realize the excavation and support of the first diameter tunnel, which simplifies the construction process and saves construction costs.

[0121] In some embodiments, after the outer ring 12 of the cutterhead separates from the first cutterhead 11, the outer ring 12 is fixedly connected to the second shield body 22 via a rib plate 123 to form the launching guide platform of the first shield body 21. This is equivalent to the outer ring of the cutterhead and at least a portion of the second shield body jointly forming the launching guide platform of the first shield body.

[0122] In some embodiments, such as before step S2, the variable-diameter tunnel construction method further includes reinforcing the strata before tunneling to a predetermined position for the variable-diameter operation. This improves the stability of the strata during the variable-diameter operation and reduces the risk of failure due to strata instability.

[0123] refer to Figure 3 In some embodiments, step S2, which involves moving the tunnel boring machine (TBM) away from the face HF by a predetermined displacement, includes: installing a jacking cylinder 6 on the front side of the TBM and having one end of the jacking cylinder 6 abut against the face HF; and using the jacking action of the jacking cylinder 6 to move the TBM away from the face HF until it reaches the predetermined displacement. This creates an operating space between the face HF and the second cutterhead, facilitating the disassembly and installation of the cutterhead and shield by operators.

[0124] To improve the stability of the tunnel boring machine (TBM) during the jacking operation, in some embodiments, before step S2 where the TBM moves away from the tunnel face HF by a preset displacement, the variable-diameter tunnel construction method further includes: performing localized treatment on the tunnel face HF. This localized treatment may include reinforcing at least a portion of the tunnel face HF to prevent damage due to excessive localized stress during jacking, thus affecting the jacking process.

[0125] During the diameter change operation of the tunnel boring machine (TBM), the shield and cutterhead adjust their positions along the tunnel axis. The rear support mechanism 52 is not essential during this process. To reduce the load during diameter change, the rear support mechanism 52 can be disengaged from the main beam 41 before the TBM moves away from the face HF at a predetermined displacement, and the entry passage within the TBM can be opened. After step S3 separates at least a portion of the second shield 22 from the first shield 21, the tail shield 213 of the first shield 21 can be fixedly connected to the rear end of the middle shield 212 of the first shield 21, and the rear support mechanism 52 of the TBM can be connected to the main beam 41.

[0126] refer to Figure 6 In some embodiments, step S3, which separates at least a portion of the second shield 22 from the first shield 21, includes separating the front shield 22a and the middle shield 22b of the second shield 22 from the first shield 21. This allows the first shield 21 to move relative to the second shield 22, thereby tunneling forward and gradually disengaging from the second shield 22.

[0127] In order for the first shield 21 to detach smoothly from the second shield 22, refer to Figure 4 and Figure 6 In some embodiments, the step of separating at least a portion of the second shield 22 from the first shield 21 further includes: providing a movable or adjustable fixed-position retaining ring 71 on the inner ring of the second shield 22, and providing a forward-moving reaction force to the first shield 21 through the retaining ring 71, so that the tunnel boring machine can advance a preset distance through the first cutterhead 11 and the first shield 21.

[0128] refer to Figure 4 and Figure 5 In some embodiments, the variable-diameter tunnel construction method further includes: before at least a portion of the second shield 22 separates from the first shield 21, assembling multiple fan-shaped segments of the shield cutting ring 25 into a ring and fixing it to the end of the first shield 21 adjacent to the outer ring 12 of the cutterhead. Since multiple fan-shaped segments have been pre-set at the upper end of the second shield near the soil chamber, removing and assembling the shield cutting ring into a ring and welding it to the end of the first shield near the soil chamber can effectively improve construction convenience and efficiency.

[0129] refer to Figure 8 In some embodiments, after separating at least a portion of the second shield 22 from the first shield 21, the variable-diameter tunnel construction method further includes separating the annular inner sleeve 222 of the second shield 22 from the annular outer sleeve 221. The annular outer sleeve of the second shield remains in the soil, while the annular inner sleeve can be removed and reused multiple times, thereby greatly saving equipment costs.

[0130] refer to Figure 9 In some embodiments, after the tail shield 213 of the first shield 21 is fixedly connected to the rear end of the middle shield 212 of the first shield 21, and the rear supporting mechanism 52 of the tunnel boring machine is connected to the main beam 41, the variable diameter tunnel construction method further includes: adjusting the segment assembly mechanism 51 from assembling the second diameter tunnel segment S2 to assembling the first diameter tunnel segment S1, and pushing at least one ring of the first diameter tunnel segment S1 backward onto the reaction base 72 installed on the second diameter tunnel segment S2 through the first propulsion mechanism 42 on the first shield 21. Here, the reaction base 72 can be fixedly installed on the second diameter tunnel segment S2 so that the tunnel boring machine can achieve the excavation of the first diameter tunnel T1 and the segment assembly through the reaction base 72.

[0131] refer to Figure 10 In some embodiments, after the tunnel boring machine passes through the reinforced stratum area, grouting can be performed on the back wall of the spliced ​​first diameter tunnel segment S1 to ensure the stability and reliability of the tunnel wall at the junction of the second diameter tunnel and the first diameter tunnel.

[0132] Based on the example of a concentric double-mode mother-daughter shield tunneling machine, combined with Figures 1-10 This explains the process of converting the main shield tunnel (the child shield tunnel is removed from its shell).

[0133] Step 1: Before changing the diameter, the formation is reinforced; no grouting is performed before reaching the replacement position (e.g., the first ring).

[0134] Step Two: Tunnel Boring Equipment Retreat and Ground Treatment (Reference) Figure 3 Specifically, the tunnel boring machine (TBM) is disconnected from the rear support mechanism and moved away by a distance H. The access passage is opened, the tunnel face is partially treated, and the jacking cylinder is installed. Then, the TBM is pushed in the opposite direction.

[0135] Step 3: Rapid Retrofitting of Tunnel Boring Equipment (Reference) Figure 4 and Figure 5 This process specifically includes:

[0136] 1. Cutterhead separation (separating the outer ring of the cutterhead from the first cutterhead and welding the outer ring of the cutterhead to the second shield body using stiffening plates);

[0137] 2. Welding the shield cut-out ring: Remove multiple fan-shaped ring segments that are pre-set at the upper end of the second shield near the earth chamber, splice them into a ring-shaped shield cut-out ring, and weld them to the end of the first shield near the earth chamber.

[0138] 3. Separate the front and middle shields of the first and second shields;

[0139] 4. Install a retaining ring on the inner ring of the second shield to provide a reaction force for the first shield;

[0140] Step 4: The first shield body advances forward a certain distance using the reaction force of the movable retaining ring (see reference). Figure 6 );

[0141] Step 5: Remove the inner shell of the annular sleeve and the outer ring of the cutterhead of the second shield (see reference). Figure 8 The outer ring sleeve of the second shield is preserved in the soil, and the inner ring sleeve can be removed and reused multiple times.

[0142] Step Six: Weld the tail shield of the first shield and connect it to the supporting mechanism. The segment assembly mechanism assembles the first diameter tunnel segments, and the propulsion mechanism inside the first shield pushes at least one ring of the first diameter tunnel segments backward onto the reaction base installed on the second diameter tunnel segments (see reference). Figure 9 );

[0143] Step 7: Utilizing the reaction force provided by multiple first-diameter tunnel segments resting against the reaction base, the first diameter tunnel is excavated and supported via the first cutterhead and the first shield. The voids behind the first-diameter tunnel segments are then filled with mortar (see reference). Figure 10 ).

[0144] Compared to existing station construction methods (open-cut / cut-and-cover), this large-diameter variable-diameter excavator achieves the goal of mechanized station construction without occupying public surface resources, making it environmentally friendly and unaffected by unforeseen factors. It also meets the continuous excavation requirements of both the station and the main line tunnel, improving overall construction efficiency and reducing costs. It has significant social and economic benefits for urban underground space development in today's complex environments and has high potential for widespread adoption.

[0145] The embodiments of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0146] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. The scope of this disclosure is defined by the appended claims.

Claims

1. A method of variable diameter tunnel construction based on a shield apparatus, characterized by, The shield device comprises: a variable-diameter shield assembly (2) having a first shield (21) for supporting a first-diameter tunnel (T1) and a second shield (22) for supporting a second-diameter tunnel (T2); and a variable-diameter cutterhead assembly (1) rotatably arranged at a front side of the variable-diameter shield assembly (2) and having a first cutterhead (11) for tunneling the first-diameter tunnel (T1) and a cutterhead outer ring (12) capable of being mounted on an outer periphery of the first cutterhead (11) to jointly form a second cutterhead with the first cutterhead (11), wherein the second cutterhead is for tunneling the second-diameter tunnel (T2); wherein a maximum diameter of the first cutterhead (11) is smaller than a maximum diameter of the second cutterhead, and a diameter of the first-diameter tunnel (T1) is smaller than a diameter of the second-diameter tunnel (T2); the variable-diameter tunnel construction method comprises: tunneling the second-diameter tunnel (T2) by the second cutterhead and tunnel supporting and segment assembling by the second shield (22); after tunneling to a preset position for diameter change, moving the shield device away from the preset position by a preset displacement relative to a working face (HF); separating the cutterhead outer ring (12) from the first cutterhead (11) and separating at least part of the second shield (22) from the first shield (21); using at least part of the second shield (22) as a starting guide table of the first shield (21), tunneling the first-diameter tunnel (T1) by the first cutterhead (11) and tunnel supporting by the first shield (21); wherein the step of separating at least part of the second shield (22) from the first shield (21) comprises: separating a front shield (22a) and a middle shield (22b) of the second shield (22) from the first shield (21); providing a movable or adjustable fixed-position blocking ring (71) at an inner ring of the second shield (22), providing a backward movement counterforce to the first shield (21) by the blocking ring (71) to make the shield device tunnel forward by the first cutterhead (11) and the first shield (21) by a preset distance; wherein the variable-diameter tunnel construction method further comprises: before separating at least part of the second shield (22) from the first shield (21), assembling multiple fan ring segments of a shield cutout ring (25) into a ring shape and fixedly connecting an end portion adjacent to one side of the cutterhead outer ring (12) on the first shield (21); after separating at least part of the second shield (22) from the first shield (21), separating a ring-shaped sleeve inner shell (222) from a ring-shaped sleeve outer shell (221) of the second shield (22).

2. The variable-diameter tunneling method of claim 1, wherein, The cutterhead outer ring (12) is mounted or separated relative to the first cutterhead (11) by a cutterhead connecting ring (13).

3. The variable-diameter tunneling method of claim 1, wherein, The cutter head outer ring (12) comprises a ring body (121) and a plurality of groups of second cutter seats (122) which are arranged on the ring body (121) in a circumferential direction of the cutter head outer ring (12).

4. The variable-diameter tunneling method of claim 3, wherein, The first cutter head (11) comprises a cutter head body (111) and a plurality of groups of first cutter seats (112) which are arranged on the cutter head body (111) in a circumferential direction of the first cutter head (11).

5. The method of claim 4, wherein, In the second cutter head formed by the cutter head outer ring (12) and the first cutter head (11), the plurality of groups of first cutter seats (112) and the plurality of groups of second cutter seats (122) correspond to each other in the circumferential direction and are aligned in the radial direction, respectively.

6. The variable-diameter tunneling method of claim 1, wherein, The shield device further comprises: A cutter head driving mechanism (3) is arranged in the variable-diameter shield body assembly (2) and is drivingly connected with the first cutter head (11) and is configured to drive the first cutter head (11) to rotate.

7. The variable-diameter tunneling method of claim 1, wherein, The second shield body (22) is a double-shell structure, which comprises an annular sleeve outer shell (221) and an annular sleeve inner shell (222), and the annular sleeve inner shell (222) is detachable relative to the annular sleeve outer shell (221).

8. The variable-diameter tunneling method of claim 1, wherein, The second shield body (22) is configured to be in sealingly connected with the outer periphery of the first shield body (21) through the first connecting mechanism (23) when being mounted to the outer periphery of the first shield body (21).

9. The variable-diameter tunneling method of claim 1, wherein, The second shield body (22) is configured to be in fixedly connected with the outer periphery of the first shield body (21) through the second connecting mechanism (24) when being mounted to the outer periphery of the first shield body (21).

10. The variable-diameter tunneling method of claim 1, wherein, The shield device further comprises: A main beam (41) is arranged in the first shield body (21) and is connected with the first shield body (21); A first propulsion mechanism (42) is arranged on the first shield body (21) and is configured to propel the first shield body (21) to excavate; A second propulsion mechanism (43) is arranged on the second shield body (22) and is configured to propel the second shield body (22) to excavate; and A segment assembling mechanism (51) is arranged on the main beam (41) and is configured to assemble segments in the first-diameter tunnel (T1) or the second-diameter tunnel (T2).

11. The method of claim 10, wherein, At least one of the first propulsion mechanism (42) and the second propulsion mechanism (43) comprises: A plurality of propulsion oil cylinders arranged in a circumferential direction.

12. The variable-diameter tunneling method of claim 1, wherein, The shield device further comprises: A shield body cutout ring (25) has a plurality of fan ring segments which can be assembled into a ring shape; The plurality of fan ring segments are configured to be fixedly arranged on an end portion of the second shield body (22) adjacent to one side of the cutter head outer ring (12) when excavating the second-diameter tunnel (T2), and to be assembled into a ring shape and fixedly connected to an end portion of the first shield body (21) adjacent to one side of the cutter head outer ring (12) after the second shield body (22) is separated from the first shield body (21).

13. The variable-diameter tunneling method of claim 1, wherein, Further comprising: Before excavating to a preset position ready for diameter change, reinforcing the stratum.

14. The method of claim 1, wherein, The step of moving the shield device away from the preset displacement relative to the working face (HF) comprises: A pushing oil cylinder (6) is arranged on the front side of the shield device, and one end of the pushing oil cylinder (6) is abutted against the working face (HF); The shield device is moved in the direction away from the working face (HF) by the pushing action of the pushing oil cylinder (6) until the position of the preset displacement from the working face (HF) is reached.

15. The method of claim 14, wherein, Before the step of moving the shield device away from the preset displacement relative to the working face (HF), the variable-diameter tunnel construction method further comprises: The working face (HF) is locally treated.

16. The method of claim 15, wherein, The step of locally treating the working face (HF) comprises: At least part of the working face (HF) is reinforced to avoid being damaged due to excessive local stress during pushing.

17. The method of claim 10, wherein, Before the step of moving the shield device away from the preset displacement relative to the working face (HF), the variable-diameter tunnel construction method further comprises: The rear matching mechanism (52) of the shield device is disengaged from the main beam (41), and the access channel in the shield device is opened.

18. The method of claim 17, wherein, After the step of separating at least part of the second shield body (22) from the first shield body (21), the variable-diameter tunnel construction method further comprises: The tail shield (213) of the first shield body (21) is fixedly connected to the rear end of the middle shield (212) of the first shield body (21), and the rear matching mechanism (52) of the shield device is connected to the main beam (41).

19. The method of claim 1, wherein, The second shield body (22) can be mounted on or separated from the outer periphery of the first shield body (21), wherein the diameter of the first shield body (21) is smaller than the diameter of the second shield body (22).

20. The method of claim 1, wherein, The cutter disc outer ring (12) can be separated from the first cutter disc (11).

21. The method of claim 10, wherein, After the step of fixing the tail shield (213) of the first shield body (21) to the rear end of the middle shield (212) of the first shield body (21) and connecting the rear matching mechanism (52) of the shield device to the main beam (41), the variable-diameter tunnel construction method further comprises: The segment assembling mechanism (51) is adjusted from assembling the second-diameter tunnel segment (S2) to assembling the first-diameter tunnel segment (S1), and at least one ring of the first-diameter tunnel segment (S1) is pushed backward by the first pushing mechanism (42) on the first shield body (21) to the reaction base (72) mounted on the second-diameter tunnel segment (S2).

22. The method of claim 21, wherein, Further comprising: The reaction base (72) is fixedly arranged on the second-diameter tunnel segment (S2) so that the shield device realizes the tunneling and segment assembling of the first-diameter tunnel (T1) through the reaction base (72).

23. The method of claim 13, wherein, Further comprising: After the shield device passes through the reinforced stratum area, grouting is performed on the wall of the spliced first-diameter tunnel segment (S1).

24. The method of claim 1, wherein, Further comprising: After the cutter disc outer ring (12) is separated from the first cutter disc (11), the cutter disc outer ring (12) is fixedly connected to the second shield body (22) through the rib plate (123) to form the starting guide table of the first shield body (21).

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