Reducing construction method and reducing heading machine

Abstract

The invention belongs to the field of tunneling, and particularly provides a variable-diameter construction method and a variable-diameter tunneling machine. The construction method comprises the steps that one end of a tail shield of the main tunneling device is dismantled so that a tunnel wall can be exposed, expanding excavation is conducted on the exposed part, a variable-diameter starting section for containing the expanding excavation device and the expanding excavation pushing device is formed, the expanding excavation device and the pushing box body are jacked from back to front from the variable-diameter starting section, and after the expanding excavation device is in place, the expanding excavation device is pushed to the tunnel wall. The propelling box body is connected with a shield body of the main tunneling device to form a shield body with a larger diameter, and a cutter head of the expanding tunneling device is matched with a cutter head of the main tunneling device to form a large cutter head with a larger diameter. The reducing heading machine is used for realizing the construction method. The variable-diameter expanding excavation in the tunnel can also be realized, the expanding excavation advancing device and the propelling box body are conveyed from back to front more conveniently and safely, an overlong propelling oil cylinder does not need to be arranged on the main tunneling device, and steering is facilitated.

Description

Technical Field

[0001] The present invention belongs to the field of tunnel boring, and particularly relates to a variable-diameter construction method and a variable-diameter boring machine. Background Art

[0002] As a safe, reliable, green and environment-friendly tunnel construction equipment, tunnel boring machines are increasingly widely used in the field of tunnel construction. With the continuous development of tunneling equipment and construction methods, the market has put forward the requirement for tunnel boring machines to excavate different diameters in different sections during tunnel construction. For example, different excavation diameters are required for tunnel sections and station sections during the excavation of subway tunnels. At present, to achieve an increase in the tunnel excavation diameter from small to large, it is still mainly achieved by setting a working shaft at the variable-diameter section and then using the mining method for excavation, resulting in low efficiency. Moreover, in some cases, the conditions for setting up a working shaft are not available, leading to difficulties in variable-diameter construction.

[0003] The Chinese patent application with the publication number CN117684999A discloses a tunnel boring machine and a variable-diameter method for the tunnel boring machine. The tunnel boring machine includes a shield body and a cutter head. The cutter head includes a sub-cutter head and a mother cutter head. The sub-cutter head is a circular cutter head structure, and the mother cutter head includes an arc-shaped segmented structure. Multiple mother cutter head segmented structures can be arranged around the outside of the sub-cutter head and spliced to form a ring-shaped mother cutter head. The shield body includes a sub-shield body and a mother shield body. The sub-shield body is a circular shield body structure, and the mother shield body includes an arc-shaped segmented structure. Multiple mother shield body segmented structures can be arranged around the outside of the sub-shield body and spliced to form a ring-shaped mother shield body. The basic structures of the sub-shield body and the sub-cutter head are basically the same as those of existing shield machines, and the sub-cutter head is provided with a radially telescopic cutting arm. After the mother cutter head and the mother shield body are spliced, a cutter head and a shield body with a larger diameter can be formed, and then a tunnel with a larger diameter can be excavated. Specifically, in implementation, the variable-diameter method includes that during normal tunneling, the sub-cutter head and the sub-shield body advance forward. When constructing to the variable-diameter area, the cutting arm on the sub-cutter head can extend. Driven by the sub-cutter head, the cutting arm can excavate a section with a larger diameter. Then, multiple arc-shaped mother cutter head segments are conveyed forward through the space at the main drive center and connected to the outside of the sub-cutter head to splice and form a cutter head with a larger diameter. Then, multiple mother shield body segments are conveyed forward through the space at the main drive center and connected to the outside of the sub-shield body to form a segmented mother shield body ring, and the multiple segmented mother shield body rings are axially connected to splice and form a shield body with a larger diameter. After all the segmented mother shield body rings are connected, propulsion cylinders can be connected to the mother shield body and then the whole is advanced forward.

[0004] In fact, there are still many problems in the actual application of the above-mentioned invention patent application. First of all, each mother shield segment is transported from the rear to the splicing position. At this time, the mother shield segment can only be spliced from the axial space between the sub-cutter head and the sub-shield body. Therefore, a relatively large space needs to be left between the sub-cutter head and the sub-shield body (normally, the axial space between the cutter head and the shield body is very small), which will result in a relatively long unsupported area, insufficient construction safety and inconvenient operation. Secondly, before all the mother shield bodies are spliced, the forward propulsion of the sub-cutter head and the sub-shield body depends entirely on the propulsion cylinders on the sub-shield body. Especially after the mother cutter head is connected, the propulsion cylinders push a cutter head with a larger diameter. Therefore, it is necessary to configure propulsion cylinders with sufficient length and large power, which will cause the sub-shield body to be too long and inconvenient to turn. Summary of the Invention

[0005] The purpose of the present invention is to provide a variable-diameter construction method to solve the technical problems of insufficient safety, inconvenient operation and poor steering performance of the variable-diameter excavation construction method in the prior art. The purpose of the present invention is also to provide a variable-diameter tunneling machine to solve the same technical problems.

[0006] To achieve the above purpose, the technical solution of the variable-diameter construction method provided by the present invention is as follows: A variable-diameter construction method: ① The main tunneling device tunnels until the variable-diameter area. After the formation is reinforced, a section of the tail shield is removed to expose the tunnel wall; ② The exposed part of the tunnel wall is excavated to form the starting section of the variable diameter; ③ A plurality of expanding pushing devices and expanding tunneling devices are placed in the starting section of the variable diameter. The expanding pushing devices and the expanding tunneling devices are arranged circumferentially to form an overall annular expanding system; ④ Each expanding pushing device pushes the corresponding expanding tunneling device to tunnel forward. After each tunneling stroke, the expanding pushing device retracts, and a propulsion box is installed in front of the expanding pushing device to continue tunneling forward until the expanding tunneling device reaches the cutter head of the main tunneling device; ⑤ The expanding pushing device is removed, and each propulsion box is connected to the shield body of the main tunneling device. Propulsion cylinders are installed on the propulsion box, and the whole moves forward.

[0007] As a further improvement, in step ③, each expanding pushing device is connected circumferentially in sequence to form an integral body.

[0008] As a further improvement, in step ⑤, it also includes connecting two adjacent propulsion boxes circumferentially and connecting two adjacent propulsion boxes axially.

[0009] As a further improvement, in step ②, a rock-breaking head that can rotate with the segment erector is installed on the segment erector of the main tunneling device. Driven by the segment erector, the rock-breaking head rotates along the tunnel axis to excavate the starting section of the variable diameter.

[0010] As a further improvement, in step ③, the segment erector grabs the excavation and pushing devices for expanding excavation, and drives the assembled ring-shaped expanding excavation system under the drive of the segment erector.

[0011] As a further improvement, in step ④, the cutter heads of two adjacent excavation and pushing devices for expanding excavation in the circumferential direction are staggered by a set distance front and back to avoid interference between adjacent cutter heads.

[0012] The present invention belongs to a pioneering invention. Its beneficial effects are as follows: When the method in the present invention is used in construction, the formation is first reinforced, which provides the basis for subsequent expanding excavation, ensuring construction safety. The variable-diameter starting section is excavated from the position of the tail shield, and the excavation and pushing devices for expanding excavation are used to expand the area outside the shield of the main tunneling device forward starting from the variable-diameter starting section. While tunneling, a propulsion box body is pushed forward by one section. After the propulsion box body is connected to the shield of the main tunneling device, the whole can be assembled into a shield with a larger diameter. The excavation and pushing devices for expanding excavation can jointly excavate with the cutter head of the main tunneling device to form a mechanism for excavating with a larger diameter. After removing the excavation and pushing devices for expanding excavation and reinstalling the propulsion cylinders, the whole can tunnel forward to excavate a tunnel with a larger diameter.

[0013] Different from the prior art, the excavation and pushing devices for expanding excavation and the propulsion box body (which will form the shield later) in the present invention are both installed from the tail shield. The space at the tail shield is large, which is actually convenient for operation. The space between the shield and the cutter head of the main tunneling device can be the same as that of the current conventional tunneling machine to ensure construction safety. At the same time, the propulsion box body and the expanding excavation driving device are equipped with a separate jacking driving device for driving them to move forward. Before the excavation and pushing devices for expanding excavation and the propulsion box body reach the position, the main tunneling device can remain stationary. That is to say, the propulsion cylinders configured for the main tunneling device can meet the normal tunneling requirements of the main tunneling device, or can be the same as the prior art. Therefore, it will not cause the main machine to be too long and can ensure the steering performance.

[0014] To achieve the above object, the technical solution of the variable-diameter tunneling machine provided by the present invention is as follows: A variable-diameter tunneling machine includes a main tunneling device, a plurality of excavation and pushing devices for expanding excavation, a plurality of excavation and pushing devices for expanding excavation with jacking, and a plurality of propulsion box bodies. The main tunneling device includes a main shield and a main cutter head. The shield includes a tail shield. The excavation and pushing devices for expanding excavation include an arc-shaped expanding shield and an expanding cutter head. The propulsion box body is an arc-shaped box structure. The excavation and pushing devices for expanding excavation with jacking include an arc-shaped base body and a jacking cylinder installed on the base body. Each adjacent excavation and pushing device for expanding excavation and excavation and pushing device for expanding excavation with jacking in the circumferential direction can be assembled into a ring-shaped expanding excavation system. The jacking cylinder is used to jack the excavation and pushing devices for expanding excavation and the propulsion box body to expand the area outside the main shield from the tail shield. The radius of the inner arc surface of the propulsion box body is equal to the outer diameter of the main shield so that the propulsion box body can be connected to the outer circumference of the main shield.

[0015] As a further improvement, the expanding cutter head is in the shape of a Reuleaux triangle.

[0016] As a further improvement, a detachable section is reserved on the tail shield to expose the tunnel wall after detachment.

[0017] As a further improvement, the main tunneling device is equipped with a segment erector, and the output end of the segment erector is equipped with a rock-breaking head connection structure for connecting the rock-breaking head to drive the rock-breaking head to rotate and excavate along the tunnel axis.

[0018] As a further improvement, the output end of the segment erector is equipped with a grasping structure for grasping the expansion tunneling device and the expansion jacking device, so as to send the expansion tunneling device and the expansion jacking device to a suitable position through the segment erector.

[0019] The present invention belongs to a pioneering invention, and its beneficial effects are as follows: When the variable-diameter tunneling machine in the present invention is under construction, when the main tunneling device tunnels to a preset variable-diameter position, it can expand and excavate outward from the position of the tail shield, and place the expansion tunneling device and the expansion jacking device into the variable-diameter starting section formed by the expansion excavation. While tunneling, a propulsion box body is jacked forward by one section. After the propulsion box body is connected to the shield body of the main tunneling device, the whole can be spliced into a shield body with a larger diameter, and the expansion tunneling device can jointly excavate with the cutter head of the main tunneling device to form a tunneling mechanism with a larger diameter, thereby realizing the excavation of a tunnel with a larger diameter.

[0020] Different from the prior art, both the expansion tunneling device and the propulsion box body (subsequently forming the shield body) in the present invention are installed from the tail shield. The space at the tail shield is relatively large, which is actually convenient for operation. The space between the shield body and the cutter head of the main tunneling device can be the same as that of the current conventional tunneling machine to ensure construction safety. At the same time, the propulsion box body and the expansion driving device are equipped with a jacking driving device for driving them to move forward separately. Before the expansion tunneling device and the propulsion box body reach the position, the main tunneling device can remain stationary. That is to say, the propulsion cylinders configured on the main tunneling device can meet the normal tunneling requirements of the main tunneling device, or can be the same as the prior art. Therefore, it will not cause the main machine to be too long and can ensure the steering performance. Description of the Drawings

[0021] Figure 1 It is a schematic diagram of the variable-diameter construction method embodiment in the present invention at the start of the expansion tunneling; Figure 2 For Figure 1 the structural schematic diagram of the main tunneling device in Figure 3 For Figure 1 the structural schematic diagram of the expansion tunneling device in Figure 4 For Figure 3 the axial view of the propulsion box body in Figure 5 It is the axial view after the splicing of each propulsion box body is completed; Figure 6 is Figure 3 Axial view (rear view) of the middle expansion tunneling device; Figure 7 is the axial view (rear view) after the middle expansion tunneling devices are assembled; Figure 8 is Figure 3 front view of the middle expansion cutter head; Figure 9 is Figure 8 schematic diagram of the expansion tunneling trajectory of the middle expansion cutter head; Figure 10 is Figure 1 schematic diagram of the expansion tunneling trajectory fitted by the middle expansion tunneling devices; Figure 11 is a schematic diagram of the embodiment of the variable diameter construction method in the present invention after the expansion tunneling device arrives in place; Figure 12 is a schematic diagram of the embodiment of the variable diameter construction method in the present invention after the main tunneling device and the expansion tunneling device are advanced integrally.

[0022] Explanation of reference numerals: 1. Main tunneling device; 2. Expansion tunneling device; 3. Expansion jacking device; 4. Propulsion box; 5. Rock breaking head; 6. New propulsion cylinder; 7. New tail shield; 101. Main cutter head; 102. Segment erector; 103. Tail shield; 1031. Detachable section; 201. Expansion cutter head; 202. Expansion shield. Detailed implementation manners

[0023] To solve the problems pointed out in the background art, the basic technical concept of the present invention is to start expanding outward from a set position at the tail shield of the main tunneling device, and start the expansion jacking device and the expansion tunneling device based on the principle of the pipe jacking machine from a position with a larger diameter formed after expanding from the tail shield, and jack the expansion tunneling device and the propulsion box that will form the "large shield" from the back to the front. During this process, the main tunneling device remains stationary, and the expansion jacking device is used to send the propulsion box and the expansion tunneling device to the appropriate position from the back to the front to form a "cutter head" and a "shield" that can expand to a larger diameter.

[0024] Based on the above concept, the present invention will be further described in detail below in conjunction with embodiments.

[0025] Specific embodiments of the variable diameter construction method provided by the present invention: In the initial stage of construction, such as Figure 1As shown, conventional tunneling machines can be used for excavation, such as the earth pressure balance shield machine or the slurry balance shield machine shown in the figure. Specifically, it includes a cutter head, a shield body, a segment erector 102, etc. The shield body includes a tail shield 103. At this time, the construction process is the same as the prior art and will not be elaborated here. For the sake of description, the tunneling machine used at this time can be defined as the main tunneling device 1, the cutter head can be defined as the main cutter head 101, and the shield body can be positioned as the main shield body.

[0026] When the main tunneling device 1 tunnels to the variable diameter section, the stratum is reinforced. Specifically, the reinforcement can adopt bolt + grouting support. After the bottom layer is reinforced, as Figure 1 shown, a section on the tail shield 103 can be removed to expose the tunnel wall.

[0027] After that, the exposed part of the tunnel wall is excavated to form a variable diameter part with a larger diameter, and this part can be defined as the variable diameter starting section.

[0028] Specifically during the excavation, as Figure 1 and Figure 2 shown, a rock breaking head 5 can be installed at the output end of the segment erector 102, such as a cutting head equipped with picks or a cutting cutter head equipped with disc cutters, etc. Driven by the segment erector 102, when the output end of the segment erector 102 rotates, it can drive the rock breaking head 5 to rotate in a full circle (along the tunnel axis), thereby excavating the variable diameter starting section. That is to say, for the segment erector 102 of the main tunneling device 1, its output end is configured with a rock breaking head connection structure for connecting the rock breaking head 5. In addition, the working stroke of the segment erector 102 should meet the excavation requirements of the rock breaking head 5.

[0029] However, it should be noted that in other embodiments, it is not completely excluded to use other excavation structures for the excavation operation of the variable diameter starting section. For example, a separate set of excavating robotic arm system can be used for variable diameter excavation. However, it is easy to understand that it is more convenient to use the segment erector 102 to install the rock breaking head 5 to achieve "one machine with multiple functions".

[0030] After the excavation of the variable diameter starting section is completed, multiple expansion pushing devices 3 and expansion tunneling devices 2 are placed. That is to say, for the variable diameter tunneling machine implementing the construction method in this embodiment, in addition to the main tunneling device 1, it also includes multiple expansion pushing devices 3 and multiple expansion tunneling devices 2. The expansion pushing devices 3 and the expansion tunneling devices 2 are corresponding pushing devices and tunneling devices based on the pipe jacking machine principle. Most basically, as Figure 3As shown in the figure, the expanding excavation and pushing device 3 includes a base body and a pushing oil cylinder installed on the base body. The base body plays a role in supporting and bearing the reaction force of the pushing oil cylinder, acting as a reaction frame. When the pushing oil cylinder extends, it can push the expanding excavation device 2 to advance forward. The expanding excavation device 2 also includes a shield body and a cutter head. For the convenience of description, the shield body here can be defined as the expanding shield body 202, and the cutter head can be defined as the expanding cutter head 201. A main drive for driving the rotation of the expanding cutter head 201 is installed on the expanding shield body 202, and specifically, an electric motor or a hydraulic motor can be used.

[0031] As Figure 6 and Figure 7 shown in the figure, both the base body of the expanding excavation and pushing device 3 and the expanding shield body 202 are arc-shaped structures. After multiple expanding excavation and pushing devices 3 and expanding excavation devices 2 are placed at the starting section of the diameter change, two adjacent base bodies in the circumferential direction can be joined together to form a complete ring structure, and two adjacent expanding base bodies can be joined together to form a complete ring structure. Overall, the expanding excavation and pushing device 3 and the expanding excavation device 2 constitute a ring-shaped expanding excavation system.

[0032] In addition, in order to enable the expanding excavation device 2 to advance forward, naturally, for the diameter-changing tunneling machine, it also includes a plurality of propulsion boxes 4. The propulsion boxes 4 are used to continuously transmit the pushing force of the expanding excavation and pushing device 3 forward and subsequently form a part of a "larger shield body" with a larger diameter. Therefore, as Figure 4 and Figure 5 shown in the figure, the propulsion boxes 4 should also be arc-shaped structures, and the radius of the inner arc surface of the propulsion boxes 4 is equal to the radius (outer diameter) of the outer arc surface of the main shield body of the main tunneling device 1, which provides the basis for firmly connecting each propulsion box 4 to the main shield body of the main tunneling device 1 subsequently.

[0033] After the above-mentioned ring-shaped expanding excavation system is assembled, the expanding excavation and pushing device 3 and the expanding excavation device 2 can be started. Each expanding excavation and pushing device 3 pushes the corresponding expanding excavation device 2 to advance forward. This process is similar to the forward pushing process of a pipe jacking machine. After each excavation section is completed, the expanding excavation and pushing device 3 retracts (specifically, the pushing oil cylinder retracts). A propulsion box 4 is installed in front of the expanding excavation and pushing device 3, and then the process is continued and repeated until the expanding excavation device 2 reaches the cutter head of the main tunneling device 1.

[0034] After the expanding excavation device 2 has advanced to the designated position, the expanding excavation and pushing device 3 can be removed, as Figure 11As shown, each propulsion box body 4 is connected to the main shield body of the main tunneling device 1 (such as by welding or bolt connection). At this time, the propulsion box body 4 and the main shield body together form a "large shield body" with a larger diameter. The excavation cutterheads 201 of the excavation and tunneling device 2 also have corresponding excavation ranges. Each excavation cutterhead 201 is responsible for the peripheral area of the outer main shield body, and the main cutterhead 101 of the main tunneling device 1 is responsible for the original circular area. That is to say, the excavation cutterheads 201 and the main cutterhead 101 together fit to form a "large cutterhead", and then the overall large-diameter excavation operation can be realized, that is, variable-diameter excavation is realized.

[0035] After the excavation and tunneling device 2 tunnels in place, propulsion cylinders can be installed on the propulsion box body 4. In order to distinguish from the propulsion cylinders of the original main tunneling device 1, the propulsion cylinders here can be defined as new propulsion cylinders 6, as Figure 12 shown. At this time, segments can be assembled normally and tunneling can continue forward according to the normal tunneling process. Among them, the torque of the main cutterhead 101 is provided by the main drive of the main tunneling device 1, and the torque of the excavation cutterhead 201 is provided by the main drive of the excavation and tunneling device 2. At the same time, in order to realize pressure-maintained tunneling, a tail shield can be assembled at the rear end of the propulsion box body 4. For the convenience of description, the tail shield here can be defined as a new tail shield 7. At this time, the old tail shield 103 is no longer needed and can be removed as a whole.

[0036] Generally speaking, analyzing the above process, it can be seen that this embodiment can realize "assembling" a tunneling machine with a larger excavation diameter in the tunnel to achieve large-diameter excavation. Different from the prior art, when "assembling" a large-diameter tunneling machine, the excavation shield body 202 and the excavation cutterhead 201 are "sent" from the back to the front. Obviously, the space inside the tail shield 103 is larger than the space between the cutterhead and the shield body, so this operation is more convenient, and there is no need to transform the cutterhead and the shield body of the main tunneling device 1. Moreover, during the process of "sending" the excavation cutterhead 201 and the excavation shield body 202 forward, the main tunneling device 1 remains stationary, and the construction safety is also higher. At the same time, the power for pushing the excavation and tunneling device 2 from the variable-diameter starting section to the cutterhead of the main tunneling device 1 is provided by a separate excavation pushing device 3. The main tunneling device 1 does not need to be equipped with propulsion cylinders with too high specifications, and thus the size of the main tunneling device 1 can be better controlled to ensure that the main tunneling device 1 has a high turning passability when excavating a "small-diameter" tunnel.

[0037] It should be supplemented here that during the process of the excavation and tunneling device 2 tunneling forward and the subsequent "large-diameter" tunneling process, the mud and slag generated by the excavation of the excavation cutterhead 201 can be pumped and discharged by the pumping and discharging pipes of the pumping and discharging slag configured by the excavation and tunneling device 2. The pumping and discharging pipes are reasonably arranged during the specific construction to avoid the segment erector 102 so that the segment erector 102 can work normally.

[0038] In a preferred embodiment, during the process of assembling the above-mentioned excavation and pushing devices 3 into an annular structure, two adjacent excavation and pushing devices 3 can be sequentially connected in the circumferential direction (such as by welding, bolt connection or other forms of connectors) to form an integral body, so that the excavation and pushing devices 3 at various positions can be kept stable, and the excavation and pushing devices 3, especially those at the arc top position, can be prevented from falling. However, it should be noted that in other embodiments, two adjacent excavation and pushing devices 3 in the circumferential direction may not be connected. To prevent the excavation and pushing devices 3 at the arc top position from "falling", a support device, such as a construction bench structure, can be set in the already formed "small-diameter" tunnel to support the excavation and pushing devices 3.

[0039] To enhance the strength of the "large shield body" composed of the propulsion box 4 and the main shield body, in a preferred embodiment, in addition to the most basic connection of the propulsion box 4 and the main shield body, two adjacent propulsion boxes 4 can also be connected axially and two adjacent propulsion boxes 4 can be connected circumferentially. Here, the connection can also be made by welding, bolts or connectors, etc. Obviously, at this time, a "large shield body" with stronger integrity and higher strength can be formed.

[0040] In addition, when assembling each excavation and pushing device 3 and the excavation and driving device 2, a segment erector 102 can also be used. Specifically, the excavation and driving device 2 and the excavation and pushing device 3 can be grabbed by the segment erector 102 and sent to the appropriate position under the drive of the segment erector 102 to complete the assembly of the annular excavation system. Compared with configuring other grasping and assembling mechanisms for grasping and assembling the excavation and pushing device 3 and the excavation and driving device 2, this method is more convenient and realizes "one machine with multiple functions". Of course, correspondingly, for the segment erector 102, it should be configured with a grasping structure for grasping the excavation and driving device 2 and the excavation and pushing device 3, such as a vacuum chuck in the prior art.

[0041] Considering that there may be relatively hard rock formations in some cases, to avoid excavation blind spots, ideally, the excavation trajectories of each excavation and driving device 2 should fit into a non-blind annular trajectory after fitting. In a preferred embodiment, as Figure 8 shown, the excavation cutter head 201 can adopt a Reuleaux triangle structure. At this time, the excavation trajectory of a single excavation cutter head 201 is as Figure 9 shown, which is a structure similar to a square. The overall excavation cutter heads 201 can be fitted to obtain a non-blind annular trajectory as Figure 10 shown. However, during construction at this time, it should be noted that two adjacent excavation cutter heads 201 in the circumferential direction should be staggered by a set distance to avoid interference between two adjacent excavation cutter heads 201.

[0042] However, it should be noted that in other embodiments, a circular cutter head may be used for relatively soft muddy strata, and the theoretically existing excavation blind area may be excavated and crushed by the shield body after the shield body is moved into place.

[0043] To facilitate the removal of the tail shield 103 of the main tunneling device 1, Figure 2 As shown, the tail shield 103 is provided with a detachable section 1031 for exposing the tunnel wall. The detachable section 1031 can be connected to the main body of the tail shield 103 by a detachable fastener, and can be removed when the diameter needs to be changed. Compared with directly cutting off the position to be removed on the tail shield 103 in a destructive manner in the tunnel, this method is obviously more convenient and is suitable for projects that require explosion protection (no hot cutting).

[0044] Specific embodiments of the variable diameter tunnel boring machine in the present invention: The specific embodiment of the variable diameter tunnel boring machine is the variable diameter tunnel boring machine described in the embodiment of the above-mentioned variable diameter construction method, which will not be described in detail here.

[0045] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments without creative work, or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A variable-diameter construction method, characterized in that ①The main tunneling device tunnels until it reaches the diameter-changing area. After strengthening the formation, a section on the tail shield is removed to expose the tunnel wall. ②The exposed part of the tunnel wall is excavated to form the starting section of the diameter change. ③A plurality of expanding pushing devices and expanding tunneling devices are placed in the starting section of the diameter change. The expanding pushing devices and expanding tunneling devices are arranged circumferentially to form an overall annular expanding system. ④Each expanding pushing device pushes the corresponding expanding tunneling device forward for tunneling. After each tunneling stroke, the expanding pushing device retracts, and a propulsion box is installed in front of the expanding pushing device to continue tunneling forward until the expanding tunneling device reaches the cutter head of the main tunneling device. ⑤The expanding pushing device is removed, and each propulsion box is connected to the shield of the main tunneling device. A propulsion oil cylinder is installed on the propulsion box, and the whole moves forward for tunneling.

2. The variable-diameter construction method according to claim 1, characterized in that, In step ③, the expanding pushing devices are sequentially connected circumferentially to form an integral body.

3. The variable-diameter construction method according to claim 1, characterized in that In step ⑤, it also includes connecting two adjacent propulsion boxes circumferentially and connecting two adjacent propulsion boxes axially.

4. The variable-diameter construction method according to any one of claims 1 to 3, characterized in that In step ②, a rock-breaking head that can rotate with the segment erector is installed on the segment erector of the main tunneling device. Driven by the segment erector, the rock-breaking head rotates along the tunnel axis to excavate the starting section of the diameter change.

5. The variable-diameter construction method according to claim 4, characterized in that, in In step ③, the segment erector grabs the expanding tunneling device and the expanding pushing device, and the assembly of the annular expanding system is completed under the drive of the segment erector.

6. The variable-diameter construction method according to any one of claims 1 to 3, characterized in that, In step ④, the cutter heads of two adjacent expanding tunneling devices in the circumferential direction are staggered by a set distance front and back to avoid interference between adjacent cutter heads.

7. Variable diameter tunneling machine, characterized in that, It includes a main tunneling device, a plurality of expanding tunneling devices, a plurality of expanding pushing devices, and a plurality of propulsion boxes. The main tunneling device includes a main shield and a main cutter head. The shield includes a tail shield. The expanding tunneling device includes an arc-shaped expanding shield and an expanding cutter head. The propulsion box is an arc-shaped box structure. The expanding pushing device includes an arc-shaped base body and a pushing oil cylinder installed on the base body. The adjacent expanding tunneling devices and expanding pushing devices in the circumferential direction can be assembled into an annular expanding system. The pushing oil cylinder is used to push the expanding tunneling device and the propulsion box to expand the peripheral area of the main shield from the tail shield. The radius of the inner arc surface of the propulsion box is equal to the outer diameter of the main shield, so that the propulsion box can be connected to the outer periphery of the main shield.

8. The variable-diameter tunneling machine according to claim 7, characterized in that, The expanding cutter head is in the shape of a Reuleaux triangle.

9. The variable-diameter tunneling machine according to claim 7 or 8, characterized in that, A detachable section is reserved on the tail shield to be removed to expose the tunnel wall.

10. The variable-diameter tunneling machine according to claim 7 or 8, characterized in that, The main tunneling device is equipped with a segment erector, and the output end of the segment erector is equipped with a rock-breaking head connection structure for connecting a rock-breaking head to drive the rock-breaking head to rotate along the tunnel axis for excavation.

11. The variable-diameter tunneling machine according to claim 10, wherein The output end of the segment erector is equipped with a grabbing structure for grabbing the expanding tunneling device and the expanding pushing device, so as to send the expanding tunneling device and the expanding pushing device to the appropriate position through the segment erector.

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