Variable-diameter tunneling machine and method of construction thereof

Abstract

This invention provides a variable-diameter tunnel boring machine (TBM), comprising a shield body, a main drive, a variable-diameter cutterhead, a propulsion device, and a segment assembly system. The main drive can move the variable-diameter cutterhead axially relative to the shield body. The variable-diameter cutterhead includes a cutterhead body, a reaming cutter device, and a diameter-expanding assembly. The cutterhead body is connected to the main drive. The reaming cutter device is disposed within the cutterhead body and can extend radially out of the cutterhead body to excavate soil layers and form an expanded excavation space under the drive of the cutterhead body. The diameter-expanding assembly is equipped with cutters, which are installed on the cutterhead body to expand the excavation diameter when the variable-diameter TBM expands its diameter. This invention also provides a construction method for the variable-diameter TBM. Compared with the prior art, the variable-diameter TBM and its construction method provided by this invention can achieve diameter change within the tunnel, shortening the construction cycle, simplifying and facilitating the diameter change operation, and is applicable not only to TBM diameter change but also to TBM diameter change.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction equipment technology, and in particular to a variable diameter shield tunneling machine and its construction method. Background Technology

[0002] In the construction of subway tunnels and station structures, shield tunneling is commonly used for tunnel sections, while open-cut methods are frequently employed for subway stations. Open-cut construction of station structures has a significant impact on the surrounding environment, and in some areas, existing structures or buildings on the ground preclude open-cut excavation. Platform tunnels differ in size from mainline tunnels; small-diameter tunnels are used for mainline tunnels, while large-diameter tunnels are used for station platforms. In recent years, mining methods such as freezing / grouting reinforcement have been used to enlarge platform tunnels, but these methods have long construction cycles, low safety, and high costs.

[0003] Tunnel boring machines (TBMs) are commonly used mechanical construction equipment in tunnel construction. To accommodate different tunnel construction methods, it is often necessary to change the diameter of the TBM. However, current technology is still limited to expanding the diameter outside the tunnel and reducing it inside. This method can only reduce the diameter of the TBM during tunnel construction; increasing the diameter still requires working outside the tunnel, resulting in long construction periods and cumbersome diameter-changing operations. Alternatively, a working shaft can be set up at the diameter change point, and then a different size TBM can be used for re-excavation. However, this method also suffers from long construction periods and cumbersome diameter-changing operations. Furthermore, in some situations, it is not feasible to set up a working shaft, making diameter-changing inside the tunnel impossible and causing significant inconvenience to construction. Summary of the Invention

[0004] To address the technical problems of existing tunnel boring machines (TBMs) requiring diameter changes to accommodate different tunnel construction methods, which involve long construction cycles and cumbersome operations, this invention provides a variable-diameter TBM and its construction method. Its main drive can extend and retract axially relative to the shield body, and it incorporates a reaming device within the cutterhead. This reaming device rotates with the cutterhead to perform radial reaming, creating the necessary space for diameter changes within the tunnel. This allows the TBM to change diameter within the tunnel, both increasing and decreasing its diameter, significantly shortening the construction cycle. The entire diameter-changing operation is performed within the tunnel, eliminating the need to remove the TBM or construct an additional working shaft, making the process simpler and more convenient.

[0005] A variable-diameter tunnel boring machine includes a shield body, a main drive, a variable-diameter cutterhead, a propulsion device, and a segment assembly system;

[0006] The shield body includes a variable-diameter front shield and a tail shield, with the tail shield connected to the tail end of the variable-diameter front shield;

[0007] The main drive is located inside the variable diameter front shield to drive the variable diameter cutter head to rotate;

[0008] The variable diameter cutterhead is mounted on the main drive and located at the front end of the variable diameter front shield, and the main drive can drive the variable diameter cutterhead to move axially relative to the shield body.

[0009] The propulsion device is disposed inside the variable diameter front shield to drive the variable diameter front shield to move;

[0010] The segment assembly system is located inside the variable diameter front shield to assemble the segments;

[0011] The variable diameter cutterhead includes a cutterhead body, an enlarging cutter device, and an enlarging assembly;

[0012] The cutter head body is connected to the main drive;

[0013] The excavation cutter device is disposed in the cutterhead body, and the excavation cutter device can extend radially out of the cutterhead body so as to excavate the soil layer and form an excavation space under the drive of the cutterhead body;

[0014] The diameter expansion assembly is equipped with a cutter. The diameter expansion assembly is used to be installed on the cutterhead body when the variable diameter shield machine is expanding its diameter, so as to expand the excavation diameter of the variable diameter cutterhead.

[0015] Preferably, the bottom of the variable diameter front shield is provided with a retractable support shoe, the retractable support shoe includes a support shoe cylinder and a support shoe plate, the support shoe plate is disposed at the output end of the support shoe cylinder, and the support shoe cylinder is used to drive the support shoe plate to extend when the variable diameter shield machine expands its diameter;

[0016] The variable diameter shield is provided with a telescopic support plate on its periphery. The telescopic support plate includes a support plate cylinder and a support plate. The support plate is located at the output end of the support plate cylinder. The support plate cylinder is used to drive the support plate to extend when the variable diameter shield machine expands its diameter.

[0017] Preferably, a slag-blocking ring is installed at the front end of the variable-diameter front shield.

[0018] Preferably, it also includes a force transmission ring device;

[0019] The force transmission ring device is installed on the propulsion device to transmit thrust when the variable diameter shield machine expands its diameter.

[0020] Preferably, the force transmission ring device is equipped with a wedge-shaped block segment assembly cylinder to assist in the installation of the segments;

[0021] The force transmission ring device is also equipped with a buffer pad at its tail.

[0022] Preferably, it also includes a support assembly device;

[0023] The support assembly device is mounted on the variable diameter cutterhead and can move and rotate with the variable diameter cutterhead to install support in the excavated space formed by the excavation cutter device.

[0024] A construction method for a variable-diameter tunnel boring machine (TBM), applicable to both shield tunneling and TBM methods, comprising the following steps:

[0025] The tunneling was carried out using a variable-diameter tunnel boring machine as described in any of the above-mentioned methods;

[0026] Enlarging preparation: The main drive extends axially, driving the cutterhead body to perform axial enlarging excavation;

[0027] Cutterhead widening excavation: The main drive retracts axially, the widening cutter device extends radially out of the cutterhead body, the main drive continues to drive the cutterhead body to rotate, and at the same time the main drive continues to extend axially, driving the widening cutter device to widen the surrounding soil layer to form widening excavation space;

[0028] Cutter head diameter expansion: The main drive retracts axially, rotates the cutter head body, rotates the spokes on the cutter head body to the bottom, and pushes out the spokes. The diameter expansion assembly is installed between the original cutter head body and the spokes. This step is repeated until all the diameter expansion assemblies are installed.

[0029] Shield diameter expansion: The variable diameter shield machine continues to excavate, and the variable diameter front shield enters the enlarged excavation space to expand the diameter of the variable diameter front shield;

[0030] Tail shield replacement and force transmission ring installation: Remove the tail shield from the variable diameter front shield, install the large shield tail shield on the variable diameter front shield, and install the force transmission ring device at the propulsion device to continue tunneling.

[0031] Preferably, the expansion of the cutterhead diameter and the expansion of the shield diameter further include:

[0032] Support installation: Install supports on the soil walls in the excavated space;

[0033] Slag-blocking ring installation: Install a slag-blocking ring at the front end of the variable diameter front shield.

[0034] Preferably, the method further includes, prior to the installation of the support:

[0035] Soil reinforcement: The soil walls in the excavated space are reinforced by freezing or grouting.

[0036] Preferably, in the shield diameter expansion, the variable diameter front shield completes the diameter expansion through its internally installed retractable support boots and retractable support plates.

[0037] Preferably, after the tail shield replacement and force transmission ring installation, the method further includes:

[0038] Diameter reduction preparation: The main drive extends axially, driving the cutter head body to perform axial expansion excavation;

[0039] Cutter head diameter reduction: The main drive retracts axially, rotates the cutter head body, rotates the spokes on the cutter head body to the top, removes the diameter expansion assembly installed here, and retracts the spokes. Repeat this step until all the diameter expansion assemblies are removed and all the spokes are retracted.

[0040] Tail shield replacement and force transmission ring removal: Remove the tail shield of the large shield from the variable diameter front shield, install the tail shield on the variable diameter front shield, remove the force transmission ring device, and continue tunneling;

[0041] Shield diameter reduction: The diameter of the variable diameter front shield is reduced, and slag is filled around the variable diameter front shield to continue tunneling.

[0042] Compared with existing technologies, the variable-diameter tunnel boring machine provided by this invention includes a shield body, a main drive, a variable-diameter cutterhead, a propulsion device, and a segment assembly system. The shield body includes a variable-diameter front shield and a tail shield, with the tail shield connected to the tail end of the variable-diameter front shield. The main drive is located inside the variable-diameter front shield to drive the variable-diameter cutterhead to rotate. The variable-diameter cutterhead is mounted on the main drive and located at the front end of the variable-diameter front shield, and the main drive can drive the variable-diameter cutterhead to move axially relative to the shield body. The propulsion device is located inside the variable-diameter front shield to push the segment assembly system. The variable-diameter front shield moves; the segment assembly system is set inside the variable-diameter front shield to assemble segments; wherein, the variable-diameter cutterhead includes a cutterhead body, a reaming cutter device, and a diameter-expanding assembly; the cutterhead body is connected to the main drive; the reaming cutter device is set in the cutterhead body, and the reaming cutter device can extend radially out of the cutterhead body to excavate the soil layer and form an expanded excavation space under the drive of the cutterhead body; the diameter-expanding assembly is equipped with cutters to be installed on the cutterhead body when the variable-diameter shield machine expands its diameter, so as to expand the excavation diameter of the variable-diameter cutterhead. The variable-diameter tunnel boring machine (TBM) is equipped with a reaming cutterhead device mounted on the cutterhead body. The main drive system moves the variable-diameter cutterhead axially relative to the shield body, allowing the reaming cutterhead to translate and rotate along with the cutterhead body. When the TBM needs to change its diameter, the reaming cutterhead device radially excavates the soil within the tunnel to create an enlarged excavation space, enabling the TBM's diameter to be increased within this space. This allows for diameter changes to be performed inside the tunnel, eliminating the need to remove the TBM from the tunnel and requiring no additional working shaft, thus shortening the construction period and simplifying the diameter-changing operation. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 A schematic diagram of a variable-diameter tunnel boring machine in a small-shield configuration, provided as an embodiment;

[0045] Figure 2 A schematic diagram of a variable-diameter tunnel boring machine in the large shield mode, provided as an embodiment;

[0046] Figure 3A schematic diagram of the structure prepared for diameter expansion;

[0047] Figure 4 A schematic diagram of the cutterhead excavation structure;

[0048] Figure 5 A schematic diagram of the tool head diameter expansion structure;

[0049] Figure 6 A schematic diagram of the structure for support installation;

[0050] Figure 7 A schematic diagram of the structure for installing the slag-blocking ring;

[0051] Figure 8 A schematic diagram of the shield body with enlarged diameter;

[0052] Figure 9 A schematic diagram of the structure for replacing the tail shield and installing the force transmission ring;

[0053] Figure 10 A schematic diagram of the structure prepared for diameter reduction;

[0054] Figure 11 A schematic diagram of a reduced-diameter cutter head;

[0055] Figure 12 A structural diagram illustrating the replacement of the tail shield and the removal of the force transmission ring;

[0056] Figure 13 A schematic diagram of the shield body with reduced diameter;

[0057] Figure 14 This is a schematic diagram of the structure of a variable-diameter tunnel boring machine after its diameter is reduced. Detailed Implementation

[0058] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0059] It should be noted that when a component is referred to as being "fixed to", "mounted to", or "set on" another component, it can be directly on or indirectly set on the other component; when a component is "connected" to another component, or when a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to the other component.

[0060] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0061] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" or "several" means two or more, unless otherwise explicitly specified.

[0062] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0063] This invention provides a variable-diameter tunnel boring machine (TBM), comprising a shield body, a main drive, a variable-diameter cutterhead, a propulsion device, and a segment assembly system. The shield body includes a variable-diameter front shield and a tail shield, with the tail shield connected to the tail end of the variable-diameter front shield. The main drive is located inside the variable-diameter front shield to drive the variable-diameter cutterhead to rotate. The variable-diameter cutterhead is mounted on the main drive and located at the front end of the variable-diameter front shield, and the main drive can drive the variable-diameter cutterhead to move axially relative to the shield body. The propulsion device is located inside the variable-diameter front shield to propel the variable-diameter cutterhead. The front shield moves; the segment assembly system is set inside the variable diameter front shield to assemble the segments; wherein, the variable diameter cutterhead includes a cutterhead body, a reaming cutter device, and a diameter expansion assembly; the cutterhead body is connected to the main drive; the reaming cutter device is set in the cutterhead body, and the reaming cutter device can extend radially out of the cutterhead body to excavate the soil layer and form an expanded excavation space under the drive of the cutterhead body; the diameter expansion assembly is equipped with cutters to be installed on the cutterhead body when the variable diameter shield machine expands its diameter, so as to expand the excavation diameter of the variable diameter cutterhead. The variable-diameter tunnel boring machine (TBM) is equipped with a reaming cutterhead device mounted on the cutterhead body. The main drive system moves the variable-diameter cutterhead axially relative to the shield body, allowing the reaming cutterhead to translate and rotate along with the cutterhead body. When the TBM needs to change its diameter, the reaming cutterhead device radially excavates the soil within the tunnel to create an enlarged excavation space, enabling the TBM's diameter to be increased within this space. This allows for diameter changes to be performed inside the tunnel, eliminating the need to remove the TBM from the tunnel and requiring no additional working shaft, thus shortening the construction period and simplifying the diameter-changing operation.

[0064] Please refer to the following: Figure 1 and Figure 2 This embodiment provides a variable diameter tunnel boring machine 100, which can realize the construction of main line tunnels and station tunnels in one operation. The variable diameter tunnel boring machine 100 can change from small to large and then back to small in place inside the tunnel, realizing continuous diameter change and large-scale diameter change. It can adapt to various complex strata and can be applied to other similar construction occasions, greatly improving the adaptability, safety and efficiency of the project and reducing construction costs.

[0065] The variable-diameter tunnel boring machine 100 includes a shield body 10, a main drive 20, a variable-diameter cutterhead 30, a propulsion device 40, and a segment assembly system 50. The shield body 10 includes a variable-diameter front shield 11 and a tail shield 12, with the tail shield 12 connected to the tail end of the variable-diameter front shield 11. The shield body 10 is mainly used to support the stability of the surrounding strata and provides installation interfaces for various internal equipment such as the main drive, hydraulic, and electrical components.

[0066] It should be noted that the shield body 10 can be composed of a "front shield + middle shield + tail shield" or a "front shield + tail shield". Since the front shield and the middle shield have similar functions and conversion processes, the variable diameter front shield 11 is used instead in this embodiment.

[0067] In this embodiment, the variable-diameter front shield 11 refers to a shield whose maximum outer diameter can change, thereby altering the overall diameter of the shield. Specifically, in this embodiment, the variable-diameter front shield 11 is a telescopic structure; the overall diameter of the shield is changed by the extension and retraction of corresponding telescopic components within the shield. Of course, in other embodiments, the variable-diameter front shield 11 can also be a modular structure. When it is necessary to increase the overall diameter of the shield, additional components can be assembled around the outer periphery of the variable-diameter front shield 11 to achieve the same change.

[0068] Correspondingly, to accommodate the two different diameters of the front shield, the tail shield can also have two different sizes. Specifically, in this embodiment, for ease of description, the smaller diameter tail shield is the tail shield 12, while the larger diameter tail shield is the large shield tail shield 13. That is, the tail shield of the variable diameter tunnel boring machine 100 can be provided with at least two different diameters to accommodate different excavation diameters. Preferably, to prevent external mud, slurry, water, etc., from entering the tunnel boring machine, the tail shield 12 and the large shield tail shield 13 can also be equipped with tail brushes at their tail ends to form a seal with the tunnel segments. Of course, in other embodiments, the tail brush can also be replaced by a steel plate bundle to form a seal with the tunnel segments.

[0069] The main drive 20 is disposed inside the variable diameter front shield 11, and the variable diameter cutterhead 30 is disposed on the main drive 20 and located at the front end of the variable diameter front shield 11. The main drive 20 is the power source for rotating the variable diameter cutterhead 30 and can employ different drive methods such as electric drive or hydraulic drive. The variable diameter cutterhead 30 serves to rotate and excavate the rock and soil at the working face. In this embodiment, the main drive 20 can also drive the variable diameter cutterhead 30 to move axially relative to the shield body 10; that is, the main drive 20 can not only drive the variable diameter cutterhead 30 to rotate, but also drive it to extend and retract axially. The specific structure by which the main drive 20 drives the variable diameter cutterhead 30 to move axially can be any linear drive unit, and its specific drive method can be electric drive, hydraulic drive, etc., such as electric cylinders, hydraulic cylinders, etc.

[0070] The propulsion device 40 is disposed inside the variable-diameter front shield 11 to move the variable-diameter front shield 11. The segment assembly system 50 is disposed inside the variable-diameter front shield to assemble the segment 200. The propulsion device 40 consists of several hydraulic cylinders, which provide forward propulsion to the main machine by pressing against the segment. The segment assembly system 50 is the same as a conventional shield tunnel segment assembly machine, used for assembling the segment 200, and has the translation and rotation functions of a conventional shield tunnel segment assembly machine.

[0071] The variable-diameter cutterhead 30 includes a cutterhead body 31, a widening cutter device 32, and a diameter-expanding assembly 33. The cutterhead body 31 is connected to the main drive 20. The widening cutter device 32 is disposed within the cutterhead body 31 and extends radially out of the cutterhead body 31 to excavate soil layers and form an expanded excavation space under the drive of the cutterhead body 31. It can be understood that because the widening cutter device 32 extends radially out of the cutterhead body 31, and the cutterhead body 31 is connected to the main drive 20, the main drive 20 can drive the cutterhead body 31 to rotate and translate, thereby driving the widening cutter device 32 to rotate and translate synchronously. This allows the widening cutter device 32 to widen the surrounding soil layers during rotation and translation, ultimately creating a ring-shaped widening excavation space.

[0072] In other words, the excavation cutter device 32 is used to excavate the soil layer radially to form an excavation space, thereby providing the variable diameter cutterhead 30 and the variable diameter front shield 11 with corresponding installation space through the excavated excavation space, so that the variable diameter shield machine 100 can realize the diameter change in the tunnel.

[0073] The specific structure for the excavation of the soil layer by the excavation cutter device 32 can be a roller cone drill, a cutting head, a bucket, or other mechanisms, which can be selected according to the actual soil conditions. The specific structure for realizing the radial extension and retraction of the excavation cutter device 32 can be any linear drive unit, and its specific drive form can be electric drive, hydraulic drive, etc., such as electric cylinders, hydraulic cylinders, etc.

[0074] The diameter expansion assembly 33 is equipped with a cutter. The diameter expansion assembly 33 is installed on the cutterhead body 31 during the diameter expansion of the variable-diameter tunnel boring machine (TBM) to increase the excavation diameter of the variable-diameter cutterhead 30. In other words, in this embodiment, the diameter change of the variable-diameter cutterhead 30 is achieved by installing and removing the diameter expansion assembly 33. Installing the diameter expansion assembly 33 on the cutterhead body 31 expands the diameter of the variable-diameter cutterhead 30. Removing the diameter expansion assembly 33 from the cutterhead body 31 reduces the diameter of the variable-diameter cutterhead 30. Specifically, in this embodiment, the diameter expansion assembly 33 includes a side block and a cutter.

[0075] Of course, in other embodiments, the different diameters of the cutter head can also be achieved by adding additional cutter head units to the outermost periphery of the variable diameter cutter head 30 to change the cutter head diameter; or even by replacing the outermost periphery of the variable diameter cutter head 30 with cutter head units of different lengths to change the cutter head diameter, etc. In this embodiment, the expansion assembly 33 is installed and disassembled, making the overall structure more stable and facilitating transportation and installation.

[0076] Understandably, current tunnel boring machines (TBMs) can only reduce their diameter during tunnel construction. Increasing the diameter requires operating outside the tunnel, resulting in long construction periods and cumbersome diameter-changing procedures. Alternatively, a working shaft can be installed at the diameter-changing point, followed by a different TBM of a different size. However, this method also suffers from long construction periods and cumbersome procedures. Furthermore, some situations lack the conditions for setting up a working shaft, making diameter-changing within the tunnel impossible and causing significant inconvenience. Against this backdrop, there is a need to find a new method for mechanized tunneling that allows for the simultaneous construction of mainline tunnels and station tunnels, requiring the ability to perform large-scale diameter changes on-site—both increasing and decreasing in size. This remains a problem that urgently needs to be solved by those skilled in the art.

[0077] The variable diameter tunnel boring machine 100 provided in this embodiment is equipped with the reaming cutter device 32, which is disposed on the cutterhead body 31. Driven by the translation and rotation of the cutterhead body 31, the reaming cutter device 32 can radially ream the tunnel to form an reaming space 300. This allows the variable diameter tunnel boring machine 100 to change its diameter from small to large within the tunnel without having to drag the variable diameter tunnel boring machine 100 out of the tunnel or set up an additional working shaft. This shortens the construction cycle and makes the diameter-changing operation simpler and more convenient.

[0078] Preferably, the bottom of the variable diameter front shield 11 is provided with a retractable support shoe 111. The retractable support shoe 111 includes a support shoe cylinder and a support shoe plate. The support shoe plate is disposed on the output section of the support shoe cylinder. The support shoe cylinder is used to drive the support shoe plate to extend when the variable diameter shield machine 100 expands its diameter.

[0079] The variable-diameter front shield 11 is provided with retractable support plates 112 around its periphery. It should be noted that, since the retractable support shoe 111 is provided at the bottom of the variable-diameter front shield 11 in this embodiment, the periphery of the variable-diameter front shield 11 in this embodiment does not include the bottom of the variable-diameter front shield 11, but specifically includes the top and the left and right sides. The retractable support plate 112 includes a support cylinder and a support plate. The support plate is disposed at the output end of the support cylinder, and the support plate is used to extend the support plate when the variable-diameter shield machine 100 expands its diameter.

[0080] Therefore, when the variable-diameter shield machine 100 expands its diameter, the extension of the retractable support shoe 111 can lift the entire machine and bear the weight of the main machine and the tunneling reaction force. When the variable-diameter shield machine 100 is tunneling with a small shield, the retractable support shoe 111 is fully retracted within the outer diameter of the small shield. When the variable-diameter shield machine 100 switches to tunneling with a large shield, the retractable support shoe 111 extends to achieve shield diameter expansion. The retractable support plate 112 mainly functions to extend and support the surrounding rock during diameter expansion. When the variable-diameter shield machine 100 is tunneling with a small shield, the retractable support plate 112 is fully retracted within the outer diameter of the small shield. When the variable-diameter shield machine 100 switches to tunneling with a large shield, the retractable support plate 112 extends together with the support shoe to achieve shield diameter expansion.

[0081] Preferably, a slag-blocking ring 60 is also installed at the front end of the variable-diameter front shield 11. Specifically, when the variable-diameter shield machine 100 expands its diameter, the slag-blocking ring 60 is installed around the front end of the variable-diameter front shield 11, and its main function is to prevent slag from the soil chamber from entering the rear of the shield body.

[0082] Preferably, the variable-diameter tunnel boring machine 100 further includes a force transmission ring device 70, which is installed on the propulsion device 40 to transmit thrust when the variable-diameter tunnel boring machine 100 expands its diameter. It is understood that after the variable-diameter tunnel boring machine 100 changes its diameter, the dimensions of the installed tunnel segments 200 also need to change. The main function of the force transmission ring device 70 provided in this embodiment is to solve the problem of non-concentric thrust transmission between the propulsion device 40 and the large-diameter tunnel segments 200 when the diameter changes from small to large. Specifically, the force transmission ring device 70 can be a steel structural component, assembled from sections, which facilitates transportation, installation, and disassembly.

[0083] Preferably, the force transmission ring device 70 includes a wedge-shaped segment assembly cylinder 71, which assists in the installation of the segments. Specifically, the wedge-shaped segment assembly cylinder 71 is concealed inside the force transmission ring device 70 and can extend to assist in the installation of the wedge-shaped segments. A buffer pad 72 is also installed at the tail of the force transmission ring device 70, thereby buffering the stress on the segments. The buffer pad 72 can be made of nylon / polyurethane / rubber.

[0084] Please refer to the following: Figure 6 Preferably, the variable-diameter shield tunneling machine 100 further includes a support assembly device 80, which is mounted on the variable-diameter cutterhead 30 and can move and rotate with the variable-diameter cutterhead 30 to install the support 400 in the excavation space formed by the excavation cutterhead device 32. By installing the support 400 in the excavation space through the support assembly device 80, soil stability can be further enhanced, preventing risks such as collapse in subsequent processes. Furthermore, installing the support 400 through the support assembly device 80 also further improves installation efficiency. In this embodiment, the support 400 is specifically a steel arch support, and the support assembly device 80 has functions such as steel arch gripping, lifting, and rotating. Of course, in other embodiments, anchor mesh, shotcrete support, etc., can also be used. Different reinforced supports can be selected according to the degree of soil stability.

[0085] Preferably, in this embodiment, the segment assembly system 50 has the ability to assemble segments with large axial and radial movements, and also has the ability to assemble small-diameter segments 200, large-diameter segments 200, the force transmission ring device 70, the tail shield 12, and the large shield tail shield 13.

[0086] Preferably, the variable diameter tunnel boring machine 100 further includes a muck removal system 90, which is installed in the shield body 10 to transport the soil excavated during the tunneling process of the variable diameter tunnel boring machine 100. The muck removal system 90 can select different muck removal methods depending on the geological conditions; for example, in the case of a small shield, a mud pipe / screw conveyor can be used for muck removal, while in the case of a large shield, a mud pipe can be used for muck removal.

[0087] Preferably, the variable diameter cutter head 30 is also provided with a freezing pipe 34, so that in geologically poor strata, the cutter head and the surrounding strata can be frozen to meet the needs of personnel entering the warehouse for operations.

[0088] Preferably, the tail shield 12 and the large shield tail shield 13 are both modularly assembled. When expanding the diameter, the tail shield 12 can be disassembled into sections and the large shield tail shield 13 can be assembled into sections. When reducing the diameter, the large shield tail shield 13 can be disassembled into sections or left directly in the stratum and the tail shield 12 can be assembled into sections.

[0089] Meanwhile, this embodiment also provides a construction method for a variable-diameter tunnel boring machine (TBM), which is applicable to both shield tunneling and TBM construction methods. The construction method includes the following steps:

[0090] The variable-diameter tunnel boring machine 100 is used for tunneling.

[0091] During normal construction, the variable diameter tunnel boring machine 100 excavates the soil through the variable diameter cutterhead 30, the shield body 10 supports the surrounding soil, the segment assembly system 50 assembles the segments 200, and the propulsion device 40 pushes against the segments 200 to generate forward power for the entire equipment.

[0092] Please refer to the following: Figure 3 Enlarging preparation: The main drive 20 extends axially, driving the cutterhead body 31 to perform axial enlarging excavation.

[0093] Specifically, when the tunneling reaches the preset position, the main drive 20 extends and performs axial excavation through the cutterhead body 31 to make room for the next operation of enlarging the diameter.

[0094] As an alternative, if the geological conditions are poor after the diameter expansion preparation, the cutterhead body 31 and the surrounding soil can be frozen or reinforced by pre-grouting to provide a stable and safe space for subsequent operations.

[0095] Please refer to the following: Figure 4 Cutterhead widening excavation: The main drive 20 retracts axially, and the widening cutter device 32 extends radially out of the cutterhead body 31. The main drive 20 continues to drive the cutterhead body 31 to rotate, while the main drive 20 continues to extend axially, driving the widening cutter device 32 to widen the surrounding soil layer to form a widening excavation space 300.

[0096] Specifically, after the main drive 20 retracts, it can be extended first. After extending a certain length, the excavating cutter head 32 then extends, while the cutterhead body 31 rotates to excavate the surrounding soil. This better avoids interference between the components.

[0097] As an alternative, if the stroke of the reaming cutter device 32 is insufficient, the excavation radius of the reaming cutter device 32 can be extended by adding an extension rod.

[0098] Please refer to the following: Figure 5Cutter head diameter expansion: The main drive 20 retracts axially, rotating the cutter head body 31, rotating the spokes 311 on the cutter head body 31 to the bottom, and pushing the spokes 311 out. The diameter expansion assembly 33 is then installed between the original cutter head body 31 and the spokes 311. This step is repeated until all the diameter expansion assemblies 33 are installed. That is, after one diameter expansion assembly 33 is installed, the cutter head body 31 is rotated again, rotating another spoke 311 on the cutter head body 31 to the bottom, thereby continuing to install the next diameter expansion assembly 33, until all the diameter expansion assemblies 33 are installed, thus completing the diameter expansion of the cutter head.

[0099] In this step, the main drive 20 only needs to retract slightly along the axial direction so that the front of the cutter head body 31 is separated from the working face.

[0100] Preferably, the expanded diameter cutter head further includes:

[0101] Please refer to the following: Figure 6 Support installation: The support 400 is installed on the soil wall in the excavated space 300.

[0102] Specifically, in this step, the main drive 20 is first extended fully along the axial direction, leaving space in the soil chamber for installing the support 400. After the support 400 is transported into the soil chamber, it is assembled using the support assembly device 80. This assembly of the support 400 continues until the diameter expansion tunneling is completed. This step helps prevent risks such as collapse in subsequent processes. Specifically, in this embodiment, the support 400 is a steel arch frame support.

[0103] Preferably, the method further includes, prior to the installation of the support:

[0104] Soil reinforcement: The soil walls in the excavated space 300 are reinforced by freezing or grouting. That is, when the strata are poor, freezing or grouting methods can be used to reinforce and stop water in the soil around the excavated space 300.

[0105] Understandably, when the soil layer is stable, there is no need to reinforce the soil layer or install supports.

[0106] Preferably, the support structure, after installation, further includes:

[0107] Please refer to the following: Figure 7 Slag-blocking ring installation: The slag-blocking ring 60 is installed at the front end of the variable diameter front shield 11.

[0108] Specifically, in this step, the main machine continues to advance forward (during tunneling, only the main drive 20 extends, and the whole machine pushes without load, which can reduce the thrust required for tunneling); until the front end of the shield body 10 leaves space for installing the slag-blocking ring 60, the slag-blocking ring 60 is installed to form a complete ring, preventing the soil chamber and the slag in front from entering the rear end of the shield body 10.

[0109] Please refer to the following: Figure 8 Shield diameter expansion: The variable diameter shield machine 100 continues to excavate, and the variable diameter front shield 11 enters the enlarged excavation space 300 to expand the diameter of the variable diameter front shield 11.

[0110] Preferably, in this step of shield diameter expansion, the variable diameter front shield 11 completes the diameter expansion through the retractable support shoe 111 and the retractable support plate 112 provided inside it.

[0111] Specifically, when the tunneling reaches the point where the telescopic support shoe 111 at the front end has room to extend, the telescopic support shoe 111 at the front end is extended to the required diameter expansion position of the shield body 10, and at the same time, the corresponding telescopic support plate 112 is extended; tunneling continues, and the above process is repeated until all the telescopic support shoes 111 and all the telescopic support plates 112 are extended, thereby completing the diameter expansion of the shield body.

[0112] Please refer to the following: Figure 9 Tail shield replacement and force transmission ring installation: Remove the tail shield 12 from the variable diameter front shield 11, install the large shield tail shield 13 on the variable diameter front shield 11, and install the force transmission ring device 70 at the propulsion device 40, and continue tunneling.

[0113] Specifically, when the variable diameter tunnel boring machine 100 tunnels to the position where the tail shield 12 can be removed, since the tail shield 12 is a segmented structure in this embodiment, after a single segment is removed, it can be grabbed and rotated by the segment assembly system 50, which facilitates quick disassembly. After disassembly, it can be transported to the rear of the tunnel.

[0114] The tail shield 13 of the large shield tunnel is also a segmented structure. After it is transported into the tunnel, it can be grabbed, extended and rotated by the segment assembly system 50, and the assembly of the tail shield 13 of the large shield tunnel can be completed quickly in a narrow space.

[0115] The force transmission ring device 70 is also a modular structure. After it is transported into the tunnel, it can be quickly assembled by the segment assembly system 50, similar to assembling segments.

[0116] It is understandable that after the variable-diameter tunnel boring machine 100 is enlarged, it needs to use larger diameter tunnel segments 200 for installation. Preferably, when assembling the larger diameter tunnel segments 200, the first ring can be made of steel tunnel segments to connect with the smaller diameter tunnel segments 200. Similarly, when assembling the smaller diameter tunnel segments 200, the last ring can also be made of steel tunnel segments. By fixing the smaller diameter steel tunnel segments to the larger diameter steel tunnel segments, the stress distribution can be improved. Specifically, transition ribs can be used between the larger and smaller diameter tunnel segments 200 for transition and reinforcement. More preferably, grouting can be injected into the outer side of the last few rings of smaller diameter tunnel segments 200 to form a reinforced zone, providing a good load-bearing foundation for the larger diameter tunnel segments 200. At this point, the variable-diameter tunnel boring machine 100 has completed the conversion process of the cutterhead, shield body, and tunnel segments, and the entire enlargement conversion is complete, ready to begin normal large-diameter tunneling.

[0117] To enable the variable-diameter tunnel boring machine 100 to reduce its diameter inside the tunnel, preferably, after the tail shield replacement and force transmission ring installation, the following may also be included:

[0118] Please refer to the following: Figure 10 Diameter reduction preparation: The main drive 20 extends axially, driving the cutterhead body 31 to perform axial expansion excavation.

[0119] When the large shield tunneling machine reaches the preset position, the main drive 20 extends and performs axial excavation through the cutterhead body 31 and the diameter expansion assembly 33 installed on the cutterhead body 31 to make room for the next operation.

[0120] As an alternative, if the geological conditions are poor after the diameter reduction preparation, the cutterhead body 31 and the surrounding soil can be frozen or reinforced by pre-grouting to provide a stable and safe space for subsequent operations.

[0121] Please refer to the following: Figure 11 Cutter head diameter reduction: The main drive 20 retracts axially, the cutter head body 31 is rotated, the spokes 311 on the cutter head body 31 are rotated to the top, the diameter expansion assembly 33 installed here is removed, and the spokes 311 are retracted. This step is repeated until all the diameter expansion assemblies 33 are removed and all the spokes 311 are retracted.

[0122] That is, after one of the diameter expansion components 33 is removed, the cutter head body 31 is rotated again to rotate the other spokes 311 on the cutter head body 31 to the top, so as to continue to remove the next diameter expansion component 33 until all the diameter expansion components 33 are removed, thereby completing the diameter reduction of the cutter head.

[0123] In this step, the main drive 20 only needs to retract slightly along the axial direction, so that the front of the cutter head body 31 is separated from the working face.

[0124] Please refer to the following: Figure 12 Tail shield replacement and force transmission ring removal: Remove the tail shield 13 from the variable diameter front shield 11, install the tail shield 12 on the variable diameter front shield 11, and remove the force transmission ring device 70, then continue tunneling;

[0125] After the tail shield 13 of the large shield tunnel is disconnected from the variable diameter front shield 11, the tail shield 13 can remain directly in the soil. The tail shield 12 is a modular structure. After being transported in, it can be gripped, extended, and rotated by the assembly system 50, allowing for rapid assembly of the tail shield 12 in a confined space. The force transmission ring device 70 can be disassembled and gradually transported out of the tunnel.

[0126] Specifically, in this embodiment, the tail shield replacement and force transmission ring removal also include the removal of the slag-blocking ring 60, which can be left in the soil after removal.

[0127] It is understandable that after the variable-diameter tunnel boring machine 100 is reduced in diameter, smaller diameter segments 200 need to be used for installation. Preferably, when assembling the smaller diameter segments 200, the first ring can be made of steel segments to connect with the larger diameter segments 200. Similarly, when assembling the larger diameter segments 200, the last ring can also be made of steel segments. By fixing the smaller diameter steel segments to the larger diameter steel segments, the stress distribution can be improved. Specifically, transition ribs can be used between the larger and smaller diameter segments 200 for transition and reinforcement. More preferably, grouting can be injected into the outer side of the last few rings of larger diameter segments 200 to form a reinforced zone, providing a good load-bearing foundation for the smaller diameter segments 200.

[0128] Please refer to the following: Figure 13 Shield diameter reduction: The diameter of the variable diameter front shield 11 is reduced, and slag is filled around the outside of the variable diameter front shield 11 to continue tunneling.

[0129] Specifically, in this embodiment, the diameter reduction of the variable-diameter front shield 11 is achieved by retracting the telescopic support shoes 111 and the telescopic support plates 112. During the diameter reduction process, all the telescopic support plates 112 are first retracted (if they cannot be retracted due to the excavated soil, they can be directly cut off); the shield body 10 is filled with dense excavated soil to support the weight of the main machine; all the telescopic support shoes 111 are retracted to complete the diameter reduction, and the normal small shield tunneling mode begins.

[0130] Please refer to the following: Figure 14 The reduced-diameter variable-diameter tunnel boring machine 100 continues to tunnel forward.

[0131] It should be noted that the variable diameter tunnel boring machine 100 is not limited to changing from small to large and then from large to small; it can also change from large to small and then from small to large, both of which are possible.

[0132] The variable-diameter shield tunneling machine 100 and its construction method provided in this embodiment enable the in-situ free conversion of the tunnel diameter during tunnel construction. This conversion process is reversible and can be repeated multiple times, achieving significant diameter changes and greatly improving the adaptability of the project. It achieves multi-purpose functionality, allowing a single shield tunneling machine to excavate shield tunnels of various sizes and specifications, reducing the time spent on external conversions, minimizing unnecessary shield tunneling shaft construction, and maximizing the equipment's value. Furthermore, the conversion can be completed without the need for a working shaft, saving costs and time.

[0133] The variable diameter shield machine 100 and its construction method provided in this embodiment can adapt to various strata such as hard rock, composite strata, and soft soil. If the stratum is a single soft soil stratum, the diameter can be expanded and reduced by directly using a telescopic over-excavation cutter.

[0134] It should be noted that the variable diameter cutter head 30 does not necessarily adopt the method of installing the diameter expansion component 33 in the middle after the spokes are extended. It can also adopt the type of installing the edge cutter directly on the edge of the cutter head. If the variable diameter is small, it can also adopt the type of automatic telescopic cutter to avoid personnel entering the chamber.

[0135] When the variable diameter shield machine 100 is discharging slag, it can use earth pressure / slurry mode. Large shield machines should prioritize slurry mode, but earth pressure mode can also be selected.

[0136] When the shield body 10 changes diameter, the support plate may not completely fill the circular space. When the diameter expansion is large, personnel can be selected to enter and install the uncovered area and reinforce it.

[0137] Furthermore, in strata with poor stability, freezing reinforcement and steel arch support are not necessarily required; other reinforcement methods such as pre-grouting reinforcement / spraying and anchoring can also be used. When the strata are in good condition, it is possible to choose not to reinforce the strata or use steel arch support.

[0138] It should be noted that the construction method of the variable-diameter tunnel boring machine (TBM) is applicable not only to TBMs but also to TBMs. In other words, the diameter-changing method of the variable-diameter TBM 100 is applicable not only to TBM diameter changes but also to TBM diameter changes. Any technical solution employing the same or similar concept as this invention to achieve in-tunnel diameter changes is within the protection scope of this invention.

[0139] The above description is merely an embodiment of the present invention. It should be noted that those skilled in the art can make improvements without departing from the inventive concept of the present invention, but these improvements all fall within the protection scope of the present invention.

Claims

1. A variable-diameter tunnel boring machine, characterized in that, Includes shield body, main drive, variable diameter cutterhead, propulsion device, and segment assembly system; The shield body includes a variable-diameter front shield and a tail shield, with the tail shield connected to the tail end of the variable-diameter front shield; The main drive is located inside the variable diameter front shield to drive the variable diameter cutter head to rotate; The variable diameter cutterhead is mounted on the main drive and located at the front end of the variable diameter front shield, and the main drive can drive the variable diameter cutterhead to move axially relative to the shield body. The propulsion device is disposed inside the variable diameter front shield to drive the variable diameter front shield to move; The segment assembly system is located inside the variable diameter front shield to assemble the segments; The variable diameter cutterhead includes a cutterhead body, an enlarging cutter device, and an enlarging assembly; The cutter head body is connected to the main drive; The excavation cutter head is disposed within the cutterhead body and extends radially out of the cutterhead body to excavate soil layers and form an expanded excavation space under the drive of the cutterhead body. The main drive can drive the cutterhead body to rotate and translate, thereby driving the excavation cutter head to rotate and translate synchronously. As the excavation cutter head rotates and translates, it can excavate the surrounding soil layers, ultimately creating an annular expanded excavation space. The excavated expanded excavation space provides corresponding installation space for the variable diameter cutterhead and the variable diameter front shield, allowing the variable diameter shield machine to change its diameter inside the tunnel. The diameter expansion assembly is equipped with a cutter. The diameter expansion assembly is used to be installed on the cutterhead body when the variable diameter shield machine is expanding its diameter, so as to expand the excavation diameter of the variable diameter cutterhead.

2. The variable diameter tunnel boring machine according to claim 1, characterized in that, The bottom of the variable diameter shield is provided with a retractable support shoe. The retractable support shoe includes a support shoe cylinder and a support shoe plate. The support shoe plate is located at the output end of the support shoe cylinder. The support shoe cylinder is used to drive the support shoe plate to extend when the variable diameter shield machine expands its diameter. The variable diameter shield is provided with a telescopic support plate on its periphery. The telescopic support plate includes a support plate cylinder and a support plate. The support plate is located at the output end of the support plate cylinder. The support plate cylinder is used to drive the support plate to extend when the variable diameter shield machine expands its diameter.

3. The variable diameter tunnel boring machine according to claim 1, characterized in that, The variable diameter front shield is equipped with a slag-blocking ring at its front end.

4. The variable diameter tunnel boring machine according to claim 1, characterized in that, It also includes a force transmission ring device; The force transmission ring device is installed on the propulsion device to transmit thrust when the variable diameter shield machine expands its diameter.

5. The variable diameter tunnel boring machine according to claim 4, characterized in that, The force transmission ring device is equipped with a wedge-shaped block segment assembly cylinder to assist in the installation of the segments; The force transmission ring device is also equipped with a buffer pad at its tail.

6. The variable diameter tunnel boring machine according to claim 1, characterized in that, It also includes support assembly devices; The support assembly device is mounted on the variable diameter cutterhead and can move and rotate with the variable diameter cutterhead to install support in the excavated space formed by the excavation cutter device.

7. A construction method for a variable-diameter tunnel boring machine, characterized in that, A construction method applicable to shield tunneling or TBM methods, the construction method comprising the following steps: The tunneling is carried out using a variable-diameter tunnel boring machine as described in any one of claims 1 to 6; Enlarging preparation: The main drive extends axially, driving the cutterhead body to perform axial enlarging excavation; Cutterhead widening excavation: The main drive retracts axially, the widening cutter device extends radially out of the cutterhead body, the main drive continues to drive the cutterhead body to rotate, and at the same time the main drive continues to extend axially, driving the widening cutter device to widen the surrounding soil layer to form widening excavation space; Cutter head diameter expansion: The main drive retracts axially, rotates the cutter head body, rotates the spokes on the cutter head body to the bottom, and pushes out the spokes. The diameter expansion assembly is installed between the original cutter head body and the spokes. This step is repeated until all the diameter expansion assemblies are installed. Shield diameter expansion: The variable diameter shield machine continues to excavate, and the variable diameter front shield enters the enlarged excavation space to expand the diameter of the variable diameter front shield; Tail shield replacement and force transmission ring installation: Remove the tail shield from the variable diameter front shield, install the large shield tail shield on the variable diameter front shield, and install the force transmission ring device at the propulsion device to continue tunneling.

8. The construction method of the variable diameter tunnel boring machine according to claim 7, characterized in that, The expansion of the cutterhead diameter and the expansion of the shield body also include: Support installation: Install supports on the soil walls in the excavated space; Slag-blocking ring installation: Install a slag-blocking ring at the front end of the variable diameter front shield.

9. The construction method of the variable diameter tunnel boring machine according to claim 8, characterized in that, Prior to the installation of the support, the following is also included: Soil reinforcement: The soil walls in the excavated space are reinforced by freezing or grouting.

10. The construction method of the variable diameter tunnel boring machine according to claim 7, characterized in that, In the process of shield diameter expansion, the variable diameter front shield completes the diameter expansion through its internally installed retractable support boots and retractable support plates.

11. The construction method of the variable diameter tunnel boring machine according to any one of claims 7 to 10, characterized in that, After the tail shield replacement and force transmission ring installation, the following also includes: Diameter reduction preparation: The main drive extends axially, driving the cutter head body to perform axial expansion excavation; Cutter head diameter reduction: The main drive retracts axially, rotates the cutter head body, rotates the spokes on the cutter head body to the top, removes the diameter expansion assembly installed here, and retracts the spokes. Repeat this step until all the diameter expansion assemblies are removed and all the spokes are retracted. Tail shield replacement and force transmission ring removal: Remove the tail shield of the large shield from the variable diameter front shield, install the tail shield on the variable diameter front shield, remove the force transmission ring device, and continue tunneling; Shield diameter reduction: The diameter of the variable diameter front shield is reduced, and slag is filled around the variable diameter front shield to continue tunneling.

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