Variable-diameter tunnel construction method, system and shield device

Abstract

This disclosure relates to a method, system, and shield tunneling equipment for constructing a variable diameter tunnel. The method includes: when the shield tunneling equipment completes the excavation and support of a tunnel of a first diameter through the first cutterhead (11) and the first shield body (2) of the variable diameter cutterhead assembly (1), a plurality of cutterhead blocks in the variable diameter cutterhead assembly (1) are radially extended relative to the outer periphery of the first cutterhead (11) to form a second cutterhead (12); the shield tunneling equipment continues to excavate and support along a preset excavation path through the second cutterhead (12) and the first shield body (2) to form a variable diameter operating space; within the variable diameter operating space, the first shield body (2) of the shield tunneling equipment is assembled and adjusted to form a second shield body (9); the shield tunneling equipment excavates and supports a tunnel of a second diameter through the second cutterhead (12) and the second shield body (9).

Description

Technical Field

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

[0002] Currently, station excavation generally adopts mining methods, including open-cut and tunneling methods, using manual or mechanical excavation. Some related technologies have proposed the idea of ​​using variable-diameter tunnel boring machines for station construction, continuously excavating the main line tunnel and station hall. Summary of the Invention

[0003] The inventors discovered through research that the mining methods used in related technologies, such as manual / mechanical excavation (open-cut / cut-and-cover), consume significant ground resources (roads / facilities), impacting normal urban traffic. Furthermore, station excavation generally cannot be carried out continuously with the mainline tunnel excavation using the shield tunneling method, which to some extent restricts the project's progress and affects construction efficiency.

[0004] Other related technologies have proposed the idea of ​​using variable diameter tunnel boring machines for station construction, but there is a lack of technically mature variable diameter tunnel boring machines or suitable specific construction systems, which often results in limited applicability.

[0005] In view of this, the present disclosure provides a variable diameter tunnel construction method, a variable diameter tunnel construction system, and a tunnel boring machine, which can improve the applicability of tunnel construction.

[0006] In one aspect of this disclosure, a method for constructing a variable-diameter tunnel is provided, comprising:

[0007] When the tunnel boring machine completes the excavation and support of a tunnel of the first diameter through the first cutterhead and the first shield body of the variable diameter cutterhead assembly, multiple cutterhead blocks in the variable diameter cutterhead assembly extend radially relative to the outer periphery of the first cutterhead to form a second cutterhead.

[0008] The tunnel boring machine continues to excavate and support along the preset tunneling path through the second cutterhead and the first shield body, so as to form a variable diameter operation space;

[0009] Within the variable diameter operating space, the first shield body of the tunnel boring machine is assembled and adjusted to form the second shield body;

[0010] The tunnel boring machine (TBM) uses the second cutterhead and the second shield body to excavate and support a tunnel of the second diameter.

[0011] In some embodiments, the diameter of the second diameter tunnel is larger than the diameter of the first diameter tunnel.

[0012] In some embodiments, the operation of the tunnel boring machine continuing to excavate and support along a preset tunneling path using a second cutterhead and a first shield specifically includes:

[0013] During the tunneling and support process of the tunnel boring machine, one or more movable support fixtures are set at the bottom of the first shield body.

[0014] In some embodiments, the operation of setting one or more movable support fixtures at the bottom of the first shield specifically includes:

[0015] For each time the tunnel boring machine advances and supports the first distance, a movable support fixture is set at the bottom of the first shield body.

[0016] In some embodiments, it also includes:

[0017] After the variable diameter operating space is formed, the cutter block in the variable diameter cutter head assembly is radially retracted relative to the outer periphery of the first cutter head;

[0018] The tunnel boring machine continues to excavate and support the tunnel of the first diameter along the preset excavation path through the first cutterhead and the first shield body.

[0019] In some embodiments, it also includes:

[0020] After the tunnel boring machine has tunneled to the second distance relative to the variable diameter operating space, the first tail shield and the moving support fixture of the first shield body are removed.

[0021] In some embodiments, it also includes:

[0022] After removing the first tail shield and the moving support fixture, the second front shield of the second shield body is moved into the variable diameter operating space.

[0023] In some embodiments, it also includes:

[0024] After the second front shield is moved in, the shield tunneling equipment is moved backward in the opposite direction to the preset tunneling path through the first cutterhead and the first shield body to support the first diameter tunnel, and the propulsion mechanism of the first shield body is removed.

[0025] After the propulsion mechanism is removed, the second middle shield of the second shield body is moved into the variable diameter operation space and assembled at the tail end of the second front shield.

[0026] The propulsion mechanism is assembled at the tail end of the second shield.

[0027] In some embodiments, it also includes:

[0028] After assembling the second middle shield and replacing the propulsion mechanism, the shield tunneling equipment continues to retreat and support in the opposite direction to the preset tunneling path through the first cutterhead and the first shield body until the first front shield and the second front shield are aligned in the vertical direction, so as to assemble the second front shield with the first front shield.

[0029] The second tail shield of the second shield body is sent into the variable diameter operation space and assembled at the tail end of the second middle shield.

[0030] In some embodiments, it also includes:

[0031] After the first shield body of the tunnel boring machine is assembled and adjusted to form the second shield body, multiple cutterhead blocks in the variable diameter cutterhead assembly are made to extend radially relative to the outer periphery of the first cutterhead to form the second cutterhead.

[0032] In some embodiments, it also includes:

[0033] Before the tunnel boring machine (TBM) makes its first excavation and support along the preset tunneling path using the second cutterhead and the first shield body, the first shield body is disconnected from the rear supporting mechanism.

[0034] After assembling and adjusting the first shield body of the tunnel boring machine to form the second shield body, the second shield body is connected to the subsequent supporting mechanism.

[0035] In some embodiments, it also includes:

[0036] The length of the variable diameter operation space along the preset tunneling path is greater than the length of the second shield.

[0037] In some embodiments, it also includes:

[0038] Before the tunnel boring machine (TBM) makes its first excavation along the preset tunneling path and supports the first diameter tunnel through the first cutterhead and the first shield body, the strata around the variable diameter operation space are reinforced.

[0039] In some embodiments, it also includes:

[0040] During the process of the tunnel boring machine (TBM) continuing to excavate and support the first diameter tunnel along the preset excavation path through the first cutterhead and the first shield body, the segment assembly mechanism assembles the segments and provides excavation reaction force to the TBM through the segments.

[0041] In some embodiments, it also includes:

[0042] After the tunnel boring machine has advanced to the second distance relative to the variable diameter operating space, at least some of the assembled tunnel segments are removed.

[0043] In some embodiments, it also includes:

[0044] After the second front shield is moved in, an adjustment base is set at the front end of the second front shield near the bottom surface along the preset tunneling path direction;

[0045] After the second shield body is assembled, the adjustment base is removed.

[0046] In another aspect of this disclosure, a tunnel boring machine is provided, comprising: a variable diameter shield assembly and a variable diameter cutterhead assembly, wherein the variable diameter cutterhead assembly is rotatably disposed on the front side of the variable diameter shield assembly;

[0047] The variable diameter shield assembly has the following features:

[0048] The first shield is configured to support the first diameter tunnel;

[0049] The second shield body, which is installed on the outer periphery of the first shield body, is configured to support the second diameter tunnel;

[0050] The variable diameter cutter head assembly has:

[0051] The first cutterhead is configured to excavate the tunnel of the first diameter; and

[0052] The cutterhead block is configured to extend radially relative to the outer periphery of the first cutterhead to form a second cutterhead together with the first cutterhead or to retract radially relative to the outer periphery of the first cutterhead, the second cutterhead being configured to excavate a tunnel of a second diameter.

[0053] The diameter of the first diameter tunnel is smaller than the diameter of the second diameter tunnel.

[0054] In some embodiments, it also includes:

[0055] 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.

[0056] In some embodiments, the cutter head block includes a ring body and a plurality of second cutter holders, the plurality of second cutter holders being arranged at intervals on the ring body along the circumference of the cutter head block.

[0057] 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.

[0058] In another aspect of this disclosure, a variable-diameter tunneling construction system is provided, comprising:

[0059] Such as any of the aforementioned tunnel boring machines; and

[0060] A movable support fixture is used to be installed in the variable diameter operating space and is configured to support the variable diameter operating space.

[0061] In some embodiments, the movable support fixture is disposed at the bottom of the variable diameter operating space along the length direction of the variable diameter operating space.

[0062] Therefore, according to the embodiments of this disclosure, by utilizing the diameter change of the variable diameter cutterhead assembly, a variable diameter operation space is excavated along a preset tunneling path for the tunnel boring machine to change its diameter. This variable diameter operation space does not require the use of surface resources, avoiding uncertainties arising from extensive demolition and municipal approvals. Furthermore, the entire variable diameter construction process is completed underground, significantly reducing overall construction costs and improving comprehensive construction efficiency. In addition, this variable diameter tunnel construction method eliminates the need for additional hoisting shafts, underground excavation workshops, or other spaces, reducing the impact and damage to the surrounding environment, effectively expanding the applicability and efficiency of tunnel construction, and conserving public resources. Attached Figure Description

[0063] 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.

[0064] This disclosure will become clearer with reference to the accompanying drawings and the following detailed description, wherein:

[0065] Figure 1 This is a schematic diagram of ground reinforcement according to some embodiments of the variable diameter tunnel construction method disclosed herein;

[0066] Figure 2 This is a schematic diagram of a tunnel boring machine supported by a first shield body according to some embodiments of the variable diameter tunnel construction method disclosed herein;

[0067] Figure 3 This is a schematic diagram of a variable diameter cutterhead assembly extending from a second cutterhead according to some embodiments of the variable diameter tunnel construction method disclosed herein;

[0068] Figure 4 This is a schematic diagram of a tunnel boring machine excavating through a second cutterhead according to some embodiments of the variable-diameter tunnel construction method disclosed herein;

[0069] Figure 5 This is a schematic diagram of the installation of movable support fixtures during tunneling, according to some embodiments of the variable-diameter tunnel construction method disclosed herein;

[0070] Figure 6 This is a schematic diagram of a tunnel boring machine excavating through a first cutterhead according to some embodiments of the variable-diameter tunnel construction method disclosed herein;

[0071] Figure 7 This is a schematic diagram of the disassembly of the first tail shield and the moving support fixture according to some embodiments of the variable diameter tunnel construction method disclosed herein;

[0072] Figure 8 This is a schematic diagram of the installation of a second front shield according to some embodiments of the variable-diameter tunnel construction method disclosed herein;

[0073] Figure 9This is a schematic diagram of the installation of the second shield according to some embodiments of the variable-diameter tunnel construction method disclosed herein;

[0074] Figure 10 This is a schematic diagram of the installation of the second tail shield according to some embodiments of the variable diameter tunnel construction method disclosed herein;

[0075] Figure 11 This is a schematic diagram of the supporting mechanism after the installation of the second shield body according to some embodiments of the variable diameter tunnel construction method disclosed herein;

[0076] Figure 12 This is a schematic diagram of the structure of the first cutterhead according to some embodiments of the tunnel boring machine according to the present disclosure;

[0077] Figure 13 yes Figure 3 A schematic diagram of the AA section in the diagram;

[0078] Figure 14 yes Figure 4 A schematic diagram of the BB section in the diagram;

[0079] Figure 15 yes Figure 8 A schematic diagram of the CC section.

[0080] In the diagram: 1. Variable diameter cutterhead assembly; 2. First shield body; 3. Propulsion mechanism; 4. Propulsion cylinder; 5. Segment assembly mechanism; 6. Slag conveying device; 7. Moving support fixture; 71. Moving support side block; 72. Moving support bottom block; 8. Segment; 9. Second shield body; 10. Adjustment base; 11. First cutterhead; 12. Second cutterhead; 21. First front shield; 22. First middle shield; 23. First tail shield; 91. Second front shield; 92. Second middle shield; 93. Second tail shield.

[0081] 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. Detailed Implementation

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] Figure 1 This is a schematic diagram of ground reinforcement according to some embodiments of the variable-diameter tunnel construction method disclosed herein. The cross-sectional area in the diagram represents the reinforcement range. Figure 2 This is a schematic diagram of the first shield excavation according to some embodiments of the variable-diameter tunnel construction method of this disclosure, with reference to... Figures 1-2 In one aspect of this disclosure, a method for constructing a variable-diameter tunnel is provided, comprising: when a tunnel boring machine (TBM) completes the excavation and support of a tunnel of a first diameter through a first cutterhead 11 and a first shield 2 of a variable-diameter cutterhead assembly 1, causing a plurality of cutterhead blocks in the variable-diameter cutterhead assembly 1 to extend radially relative to the outer periphery of the first cutterhead 11 to form a second cutterhead 12; causing the TBM to continue excavating and supporting along a preset excavation path through the second cutterhead 12 and the first shield 2 to form a variable-diameter operating space; assembling and adjusting the first shield 2 of the TBM within the variable-diameter operating space to form a second shield 9; and causing the TBM to excavate and support a tunnel of a second diameter through the second cutterhead 12 and the second shield 9.

[0088] In this embodiment, the diameter change of the variable diameter cutterhead assembly 1 is used to excavate a variable diameter operation space for the shield structure to change diameter on the preset tunneling path. This does not require occupying ground resources and avoids uncertainties caused by large-scale demolition and municipal approvals, so that the station excavation and the main line tunnel excavation can be carried out continuously.

[0089] Furthermore, the entire diameter-changing construction process is completed underground, which can greatly reduce the overall construction cost and improve the overall construction efficiency. In addition, this diameter-changing tunnel construction method does not require additional hoisting working shafts, underground excavation workshops, or other spaces, which can reduce the impact and damage to the surrounding environment of the tunnel, effectively improve the applicability and efficiency of tunnel construction, and save public resources.

[0090] refer to Figure 4 In some embodiments, the diameter of the second diameter tunnel is larger than that of the first diameter tunnel. In this embodiment, by excavating a space for diameter changing using a second cutterhead 12 with a larger diameter, sufficient area can be provided within the diameter changing operation space for disassembly and assembly work, thus improving construction efficiency.

[0091] In some embodiments, the diameter of the second diameter tunnel is smaller than the diameter of the first diameter tunnel. In this embodiment, the shield structure can be modified from a large diameter to a small diameter.

[0092] refer to Figures 4-5 In some embodiments, the operation of the tunnel boring machine (TBM) continuing to excavate and support along the preset tunneling path via the second cutterhead 12 and the first shield 2 specifically includes: during the excavation and support process of the TBM, setting one or more movable support fixtures 7 at the bottom of the first shield 2. In this embodiment, during the excavation process of the first shield 2, since there is a certain distance between the bottom of the excavation profile and the bottom of the first shield 2, setting one or more movable support fixtures 7 at the bottom of the first shield 2 for support can effectively avoid a series of construction difficulties such as the TBM sinking, loss of attitude control, uneven load on the main bearing, and main machine roll.

[0093] refer to Figures 4-5 and Figure 14 In some embodiments, the operation of setting one or more movable support fixtures 7 at the bottom of the first shield body 2 specifically includes: setting a movable support fixture 7 at the bottom of the first shield body 2 every time the tunnel boring machine advances a first distance. In this embodiment, the movable support fixture 7 may include a movable support side block 71 and a movable support bottom block 72, and the movable support fixture 7 can be sent into the variable diameter operation space from the middle position of the tunnel cross-sectional area.

[0094] refer to Figure 6In some embodiments, the method further includes: after forming the variable diameter operating space, retracting the cutterhead block in the variable diameter cutterhead assembly 1 radially relative to the outer periphery of the first cutterhead 11; allowing the tunnel boring machine to continue tunneling and supporting the first diameter tunnel along the preset tunneling path via the first cutterhead 11 and the first shield 2. In this embodiment, allowing the tunnel boring machine to continue tunneling a second distance along the preset tunneling path via the first cutterhead 11 and the first shield 2 facilitates the removal of the first tail shield 23.

[0095] refer to Figure 6 and Figure 7 In some embodiments, the method further includes: after the tunnel boring machine has tunneled to a second distance relative to the variable diameter operating space, removing the first tail shield 23 and the movable support fixture 7 of the first shield body 2.

[0096] refer to Figure 8 In some embodiments, the method further includes: after removing the first tail shield 23 and the movable support fixture 7, moving the second front shield 91 of the second shield body 9 into the diameter-changing operation space. In this embodiment, the second front shield 91 can be sent to the top of the diameter-changing operation space.

[0097] refer to Figures 8-10 and Figure 15 In some embodiments, the method further includes: after moving the second front shield 91 in, causing the tunnel boring machine (TBM) to retreat and support the first diameter tunnel in a direction opposite to the preset tunneling path via the first cutterhead 11 and the first shield body 2, and dismantling the propulsion mechanism 3 of the first shield body 2; after dismantling the propulsion mechanism 3, moving the second middle shield 92 of the second shield body 9 into the variable diameter operating space and assembling it at the tail end of the second front shield 91; and assembling the propulsion mechanism 3 at the tail end of the second middle shield 92. The TBM retreats via a front-end jacking cylinder, or by circumferentially sealing the gap between the outer shell of the first front shield 21 and the excavation profile, and by building air pressure in the soil chamber to retract the entire TBM. The second front shield 91 and the second middle shield 92 are sequentially assembled with the first front shield 21 by the segment assembly machine 5.

[0098] refer to Figure 10 In some embodiments, the method further includes: after assembling the second middle shield 92 and replacing the propulsion mechanism 3, allowing the tunnel boring machine to continue to retreat and support in the opposite direction to the preset tunneling path via the first cutterhead 11 and the first shield body 2, until the first front shield 21 and the second front shield 91 are vertically aligned, so as to assemble the second front shield 91 and the first front shield 21; sending the second tail shield 93 of the second shield body 9 into the variable diameter operation space and assembling it at the tail end of the second middle shield 92.

[0099] In this embodiment, the second middle shield 92 and the propulsion cylinder are pre-positioned at the top of the variable diameter operation space. During the retraction of the first shield 2, it is installed in conjunction with the first front shield 21, and the second middle shield 92 and the propulsion cylinder are installed, which helps to improve construction efficiency.

[0100] refer to Figure 11 In some embodiments, the method further includes: after assembling and adjusting the first shield body 2 of the tunnel boring machine to form the second shield body 9, causing a plurality of cutterhead blocks in the variable diameter cutterhead assembly 1 to extend radially relative to the outer periphery of the first cutterhead 11 to form the second cutterhead 12.

[0101] In some embodiments, the method further includes: before the tunnel boring machine (TBM) makes its first tunneling and support work along the preset tunneling path using the second cutterhead 12 and the first shield 2, disconnecting the first shield 2 from the rear supporting mechanism; and after the first shield 2 of the TBM is assembled and adjusted to form the second shield 9, connecting the second shield 9 to the rear supporting mechanism.

[0102] In some embodiments, the method further includes: the length of the variable diameter operation space along the preset tunneling path direction is greater than the length of the second shield 9. In this embodiment, by setting the length of the variable diameter operation space to be greater than the length of the second shield 9, the variable diameter operation space has sufficient area for assembling and disassembling the shield structure.

[0103] In some embodiments, the method further includes: before the tunnel boring machine (TBM) advances and supports the first diameter tunnel along the preset tunneling path for the first time through the first cutterhead 11 and the first shield 2, reinforcing the strata around the variable diameter operation space.

[0104] In some embodiments, the method further includes: during the process of the tunnel boring machine continuing to excavate and support a tunnel of the first diameter along a preset excavation path via the first cutterhead 11 and the first shield body 2, assembling tunnel segments by the segment assembly mechanism 5, and providing excavation reaction force to the tunnel boring machine through the segments. This embodiment includes, but is not limited to, assembling upper half-ring segments, lower half-ring segments, or complete ring segments by the segment assembly mechanism 5.

[0105] In some embodiments, the method further includes: after the tunnel boring machine has tunneled to a second distance relative to the diameter-changing operation space, removing at least a portion of the assembled tunnel segments to provide sufficient space for the diameter-changing operation.

[0106] In some embodiments, the method further includes: after the second front shield 91 is moved in, an adjustment base 10 is provided at the front end of the second front shield 91 near the bottom surface along the preset tunneling path direction; after the second shield body 9 is assembled, the adjustment base 10 is removed.

[0107] refer to Figures 1-15 The following section uses the diameter-changing process of the first shield body 2 as an example to illustrate the construction method of diameter-changing tunnels:

[0108] Before the diameter change, the ground in the construction area is reinforced. During the diameter change construction, the tunnel boring machine (TBM) first tunnels and is supported by the first cutterhead 11 and the first shield body 2 to the diameter change construction area. Then, multiple cutterhead blocks of the variable diameter cutterhead assembly 1 extend radially relative to the outer periphery of the first cutterhead 11 to form a second cutterhead 12. The TBM then uses the rotation of the second cutterhead 12 to radially cut the soil layer around the second cutterhead 12 to achieve diameter expansion. The soil layer includes, but is not limited to, soft soil layers. The first shield body 2 is disconnected from the rear supporting mechanism. The TBM then performs its first tunneling and support through the second cutterhead 12 and the first shield body 2 of the variable diameter cutterhead assembly 1 to create the diameter change operation space.

[0109] During the first tunneling operation, for every distance the tunnel boring machine (TBM) advances by one mobile support fixture, a mobile support fixture 7 is installed at the bottom of the first front shield 21, until the excavation reaches a space sufficient to assemble the second shield 9. The tunnel segments are then assembled using the segment assembly mechanism 5. The mobile support fixtures are transported from outside the tunnel to the bottom of the first front shield 21 via a pre-reserved material transport channel, and are positioned at the bottom of the variable-diameter operating space.

[0110] Multiple cutterhead blocks of the variable-diameter cutterhead assembly 1 retract radially relative to the outer periphery of the first cutterhead 11, thereby adjusting from the second cutterhead 12 to the first cutterhead 11. The tunnel boring machine (TBM) then performs a second excavation and support operation via the first cutterhead 11 and the first shield body 2. During the second excavation, the TBM advances to a distance sufficient for dismantling the first tail shield 23 and the movable support fixture 7. After the second excavation, the first tail shield 23, the tunnel segments, the movable support fixture 7, and the tunnel segments within the variable-diameter space are dismantled to reserve space for the subsequent assembly of the second shield body 9.

[0111] The second front shield 91 and the second middle shield 92 are sent into the variable diameter operating space. The shield machine is moved back until the first front shield 21 and the second front shield 91 are aligned. The propulsion mechanism 3 is disassembled from the first shield body 2. The first front shield 21, the second front shield 91 and the second middle shield 92 are assembled into a ring sleeve in sequence using the segment assembly mechanism 5. The propulsion mechanism 3 is installed at the tail of the second middle shield 92.

[0112] The first front shield 21 of the tunnel boring machine (TBM) is moved backward together with the assembled second front shield 91 and second middle shield 92. The second tail shield 93 is then assembled behind the second middle shield 92. Multiple cutterhead blocks of the variable diameter cutterhead assembly 1 extend radially relative to the outer periphery of the first cutterhead 11 to form the second cutterhead 12. After connecting to the tail end of the second tail shield 93, the assembly of the second shield body 9 is completed. The TBM can then excavate and support a tunnel of the second diameter through the second cutterhead 12 and the second shield body 9.

[0113] In another aspect of this disclosure, a tunnel boring machine (TBM) is provided, comprising: a variable-diameter shield assembly and a variable-diameter cutterhead assembly 1, wherein the variable-diameter cutterhead assembly 1 is rotatably disposed on the front side of the variable-diameter shield assembly. The variable-diameter shield assembly has a first shield 2 and a second shield 9, wherein the first shield 2 is configured to support a tunnel of a first diameter, and the second shield 9 is mounted on the outer periphery of the first shield 2 and configured to support a tunnel of a second diameter.

[0114] Figure 12 This is a schematic diagram of the structure of the first cutter head 11. Figure 13 This is a schematic diagram of the structure of the second cutter head 12, for reference. Figure 12 and Figure 13 The variable-diameter cutterhead assembly 1 includes a first cutterhead 11 and cutterhead blocks. The first cutterhead 11 is configured to excavate a tunnel of a first diameter. The cutterhead blocks are configured to extend radially relative to the outer periphery of the first cutterhead 11 to form a second cutterhead 12 together with the first cutterhead 11, or to retract radially relative to the outer periphery of the first cutterhead 11. The second cutterhead 12 is configured to excavate a tunnel of a second diameter, the diameter of which is smaller than that of the first diameter tunnel. The variable-diameter cutterhead assembly 1 can achieve free large-diameter expansion during excavation. Half of the main beam has a telescopic function. Through a combination of techniques such as main beam telescopic expansion and adding cutters in a reserved empty cutter box, the needs of excavation in complex geological formations can be met. The smaller cutterhead is used for excavating small-diameter tunnels; the expanded large cutterhead is used to increase the cutterhead diameter to achieve large-diameter excavation. The variable-diameter cutterhead assembly 1 can quickly adjust the excavation stroke and is easy to operate.

[0115] In some embodiments, it further includes: a cutterhead drive mechanism disposed within the variable diameter shield assembly and drivenly connected to the first cutterhead 11, configured to drive the first cutterhead 11 to rotate.

[0116] In some embodiments, the variable diameter cutter head assembly 1 includes a cutter head connecting ring, through which the cutter head block is mounted or detached relative to the first cutter head 11.

[0117] In some embodiments, the cutter head block includes a ring body and a plurality of second cutter holders, the plurality of second cutter holders being arranged at intervals on the ring body along the circumference of the cutter head block.

[0118] In some embodiments, the first cutter head 11 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 11.

[0119] In some embodiments, in the second cutter head 12 formed by the cutter head block and the first cutter head 11, multiple sets of first cutter holders and multiple sets of second cutter holders correspond one-to-one in the circumferential direction and are respectively aligned in the radial direction.

[0120] In some embodiments, the first shield 2 has a detachable first front shield 21, a first middle shield 22, and a first tail shield 23, and the second shield 9 has a detachable second front shield 91, a second middle shield 92, and a second tail shield 93. During the diameter change process, the segmented outer shells of the second front shield 91, the second middle shield 92, and the second tail shield 93 are transported from outside the shaft to the vicinity of the area that the segment assembly mechanism 5 can grasp using a train.

[0121] In some embodiments, it further includes: a main beam disposed within the first shield body 2 and connected to the first shield body 2.

[0122] In some embodiments, the system further includes a propulsion mechanism 3 and a segment assembly mechanism 5. The propulsion mechanism 3 is optionally mounted on the first shield 2 or the second shield 9 and is configured to propel the first shield 2 or the second shield 9 for tunneling. The segment assembly mechanism 5 is mounted on the main beam and is configured to assemble segments within the first diameter tunnel or the second diameter tunnel. The segment assembly mechanism 5 uses tooling to sequentially assemble the multi-component modular shells of the second front shield 91, the second middle shield 92, and the second tail shield 93 into a front shield ring structure, a middle shield ring structure, and a tail shield ring structure. These ring structures are sequentially fitted and connected to the first shield 2 to form the second shield 9.

[0123] In some embodiments, the propulsion mechanism 3 includes a plurality of propulsion cylinders 4 arranged at intervals along the circumference of the first shield body 2. The propulsion mechanism 3, the rear supporting mechanism, the excavated soil conveying device 6, the segment assembly mechanism 5, etc., can meet the construction requirements of various diameter tunneling modes without modification.

[0124] In some embodiments, the system further includes: a muck conveying device 6 and a slurry circulation system. The muck conveying device 6 is configured to discharge muck generated during the tunneling process, and the slurry circulation system is configured to replenish slurry during the tunneling process.

[0125] In another aspect of this disclosure, a variable-diameter tunneling construction system is provided, comprising:

[0126] Such as any of the aforementioned tunnel boring machines; and

[0127] The movable support fixture 7 is used to be installed in the variable diameter operating space and is configured to support the variable diameter operating space.

[0128] In some embodiments, the movable support fixture 7 is disposed at the bottom of the variable diameter operating space along the length direction of the variable diameter operating space.

[0129] 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.

[0130] 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, characterised in that, include: When the tunnel boring machine completes the excavation and support of the first diameter tunnel through the first cutterhead (11) and the first shield (2) of the variable diameter cutterhead assembly (1), multiple cutterhead blocks in the variable diameter cutterhead assembly (1) extend radially relative to the outer periphery of the first cutterhead (11) to form a second cutterhead (12). The shield tunneling equipment continues to tunnel and support along the preset tunneling path through the second cutterhead (12) and the first shield (2). During the tunneling and support process of the shield tunneling equipment, one or more movable support fixtures (7) are set at the bottom of the first shield (2) until the tunneling reaches a spatial distance that can be used to assemble the second shield (9) to form a variable diameter operation space. After the variable diameter operating space is formed, the cutter block in the variable diameter cutter head assembly (1) is radially retracted relative to the outer periphery of the first cutter head (11); The shield tunneling equipment continues to excavate and support the first diameter tunnel along the preset excavation path through the first cutterhead (11) and the first shield body (2) until it has been excavated to the distance required to remove the first tail shield (23) and the moving support fixture (7); Within the variable diameter operating space, the first shield body (2) of the shield tunneling equipment is assembled and adjusted to form the second shield body (9). After the second shield body (9) is formed, a plurality of cutterhead blocks in the variable diameter cutterhead assembly (1) are made to extend radially relative to the outer periphery of the first cutterhead (11) to form the second cutterhead (12), so that the shield tunneling equipment can excavate and support a second diameter tunnel through the second cutterhead (12) and the second shield body (9).

2. The method of claim 1, wherein, The diameter of the second diameter tunnel is larger than the diameter of the first diameter tunnel.

3. The variable-diameter tunnel construction method as described in claim 1, characterized in that, The operation of setting one or more movable support fixtures (7) at the bottom of the first shield body (2) specifically includes: For each time the tunnel boring machine advances a first distance, a movable support fixture (7) is set at the bottom of the first shield body (2).

4. The variable-diameter tunnel construction method as described in claim 1, characterized in that, Also includes: After the tunnel boring machine has tunneled a second distance relative to the variable diameter operating space, the first tail shield (23) and the moving support fixture (7) of the first shield body (2) are removed.

5. The variable-diameter tunnel construction method as described in claim 4, characterized in that, Also includes: After removing the first tail shield (23) and the mobile support fixture (7), the second front shield (91) of the second shield body (9) is moved into the variable diameter operation space.

6. The variable-diameter tunnel construction method as described in claim 5, characterized in that, Also includes: After the second front shield (91) is moved in, the shield machine is moved backward in the opposite direction to the preset tunneling path through the first cutterhead (11) and the first shield body (2) to support the first diameter tunnel, and the propulsion mechanism (3) of the first shield body (2) is removed. After removing the propulsion mechanism (3), the second middle shield (92) of the second shield body (9) is moved into the variable diameter operation space and assembled at the tail end of the second front shield (91); The propulsion mechanism (3) is assembled at the tail end of the second middle shield (92).

7. The variable-diameter tunnel construction method as described in claim 6, characterized in that, Also includes: After assembling the second middle shield (92) and replacing the propulsion mechanism (3), the shield tunneling equipment continues to retreat and support in the opposite direction to the preset tunneling path through the first cutterhead (11) and the first shield body (2) until the first front shield (21) of the first shield body (2) and the second front shield (91) are aligned in the vertical direction, so as to assemble the second front shield (91) and the first front shield (21). The second tail shield (93) of the second shield body (9) is sent into the variable diameter operation space and assembled at the tail end of the second middle shield (92).

8. The variable-diameter tunnel construction method as described in claim 1, characterized in that, Also includes: Before the shield tunneling equipment makes its first excavation and support along the preset tunneling path through the second cutterhead (12) and the first shield body (2), the first shield body (2) is disconnected from the rear supporting mechanism; After assembling and adjusting the first shield body (2) of the tunnel boring machine to form the second shield body (9), the second shield body (9) is connected to the rear supporting mechanism.

9. The variable-diameter tunnel construction method as described in claim 1, characterized in that, Also includes: The length of the variable diameter operation space along the preset tunneling path is greater than the length of the second shield (9).

10. The variable-diameter tunnel construction method as described in claim 1, characterized in that, Also includes: Before the shield tunneling equipment excavates and supports the first diameter tunnel along the preset tunneling path for the first time through the first cutterhead (11) and the first shield body (2), the strata around the variable diameter operation space are reinforced.

11. The variable-diameter tunnel construction method as described in claim 1, characterized in that, Also includes: During the process of the tunnel boring machine continuing to excavate and support the first diameter tunnel along the preset excavation path through the first cutterhead (11) and the first shield body (2), the segment assembly mechanism (5) assembles the segments and provides excavation reaction force to the tunnel boring machine through the segments.

12. The variable-diameter tunnel construction method as described in claim 11, characterized in that, Also includes: After the tunnel boring machine has tunneled to a second distance relative to the variable diameter operating space, at least some of the assembled tunnel segments are removed.

13. The variable-diameter tunnel construction method as described in claim 5, characterized in that, Also includes: After the second front shield (91) is moved in, an adjustment base (10) is set at the front end of the second front shield (91) near the bottom surface along the preset tunneling path direction. After the second shield body (9) is assembled, the adjustment base (10) is removed.

14. A tunnel boring machine (TBM) for use in the variable-diameter tunnel construction method according to any one of claims 1 to 13, characterized in that, include: A variable diameter shield assembly and a variable diameter cutterhead assembly (1), wherein the variable diameter cutterhead assembly (1) is rotatably disposed on the front side of the variable diameter shield assembly; The variable diameter shield assembly has the following features: The first shield (2) is configured to support the first diameter tunnel; The second shield (9) is installed on the outer periphery of the first shield (2) and is configured to support the second diameter tunnel; The variable diameter cutter head assembly (1) has: The first cutterhead (11) is configured to excavate the tunnel of the first diameter; and The cutterhead block is configured to extend radially relative to the outer periphery of the first cutterhead (11) to form a second cutterhead (12) together with the first cutterhead (11) or to retract radially relative to the outer periphery of the first cutterhead (11), the second cutterhead (12) being configured to excavate a tunnel of the second diameter; The diameter of the first diameter tunnel is smaller than the diameter of the second diameter tunnel.

15. The tunnel boring machine as described in claim 14, characterized in that, Also includes: The cutterhead drive mechanism is disposed within the variable diameter shield assembly and is drivenly connected to the first cutterhead (11), and is configured to drive the first cutterhead (11) to rotate.

16. The tunnel boring machine as described in claim 14, characterized in that, The cutter head block includes a ring body and multiple sets of second cutter holders, which are arranged at intervals on the ring body along the circumference of the cutter head block.

17. The tunnel boring machine as described in claim 16, characterized in that, The first cutter head (11) includes a cutter head body and multiple sets of first tool holders, which are arranged at intervals on the cutter head body along the circumference of the first cutter head (11).

18. A variable-diameter tunneling construction system, characterized in that, include: The tunnel boring machine as described in any one of claims 14 to 17 above; and The movable support fixture (7) is installed in the variable diameter operating space and is configured to support the variable diameter operating space.

19. The tunnel boring machine as described in claim 18, characterized in that, The movable support fixture (7) is arranged at the bottom of the variable diameter operation space along the length direction of the variable diameter operation space.

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