Tunneling construction method of cantilever type tunneling machine, inverted arch cushion block and assembled pavement structure

Abstract

The invention belongs to the technical field of lining of underground chambers, and particularly provides a tunneling construction method of a cantilever type tunneling machine, an inverted arch cushion block and an assembled pavement structure. The construction method comprises the following steps: (1) assembling an annular arch support structure in front of the cantilever type heading machine; (2) paving a passage pavement structure for protecting the inverted arch frame; and (3) the cantilever type heading machine continues to conduct heading forwards along the laid passing pavement structure. The inverted arch cushion block is used for being spliced into a passage pavement structure for the cantilever type heading machine to pass through. In the construction process, the arch supporting structure assembled by the cantilever type heading machine is of a complete annular structure, the supporting strength is higher, under the protection effect of a passing pavement structure, the inverted arch cannot be crushed by the cantilever type heading machine, and the inverted arch supporting structure is suitable for weak surrounding rock construction.

Description

Technical Field

[0001] The invention belongs to the technical field of lining of underground chambers, and in particular relates to a cantilever type tunneling machine tunneling construction method, an inverted arch pad and an assembled pavement structure. Background Art

[0002] The cantilever tunnel boring machine includes a chassis equipped with a crawler walking mechanism, a cantilever installed on the chassis that can swing up and down and left and right, a rock breaking mechanism (usually a cutting head) installed on the cantilever, and a loading mechanism supported by the chassis. The loading mechanism includes a shovel and a conveyor, which are mainly used to collect and transport the excavated soil backwards.

[0003] The basic function of a cantilevered tunnel boring machine is to excavate and break rock. When constructing in soft surrounding rock geology, in order to control the deformation of the surrounding rock and prevent the surrounding rock from collapsing, it is generally necessary to construct an arch support structure on the tunnel wall. The construction of the arch support structure includes the process of assembling the arch. The arch is generally assembled by using a suitable arch trolley. During the construction process, the arch trolley follows the cantilevered tunnel boring machine to perform arch support operations. However, for poor grade broken and fissured geology, this method has the problem of untimely support and high safety risks.

[0004] The patent document with application publication number CN114233313A discloses a tunnel construction method suitable for a multifunctional cantilever tunnel boring machine. The cantilever tunnel boring machine used in the method is provided with a sliding platform that can slide forward and backward in two stages, and an arch frame installation mechanism is installed on the left and right sides of the sliding platform. The arch frame installation mechanism is specifically a multi-degree-of-freedom mechanical arm that can swing up and down and left and right, and the mechanical arm can clamp the arch frame. During construction, the arch frame installation mechanism can move forward and backward with the sliding platform, and cooperate with its own up and down, left and right swings to send the arch frame to the assembly position, completing the C-type arch frame support structure.

[0005] The above construction method can realize the assembly of arch frames in front of the cantilever tunnel boring machine by integrating the arch frame installation mechanism on the cantilever tunnel boring machine. Analysis of the structure of the cantilever tunnel boring machine shows that the assembly of the left and right arch frame installation mechanisms can easily complete the assembly of the top arch frame and the left and right side arch frames. It is not disclosed whether the inverted arch frame is assembled, and the arch frame support structure finally assembled by this method is also a C-shaped structure. The arch frame support structure does not form a ring, and there is still a high safety hazard for the surrounding rock of poor grade. Summary of the invention

[0006] The purpose of the present invention is to provide a cantilevered tunnel boring machine excavation construction method to solve the technical problem of high safety hazards of cantilevered tunnel boring machines in soft surrounding rock geology in the prior art. The purpose of the present invention is also to provide an inverted arch pad and an assembled pavement structure that can be used in the above construction method.

[0007] To achieve the above-mentioned purpose, the technical solution of the cantilever type tunnel boring machine tunneling construction method provided by the present invention is: A cantilever tunneling construction method comprises the following steps: 1) assembling a ring-shaped arch support structure in front of the cantilever tunneling machine; 2) laying a traffic pavement structure for protecting the inverted arch frame; and 3) the cantilever tunneling machine continues to advance along the laid traffic pavement structure.

[0008] As a further improvement, the side arch frame and the top arch frame are first assembled in front of the cantilevered tunnel boring machine, then the debris at the bottom of the tunnel is cleared, and then the invert arch frame is assembled to form a ring with the side arch frame and the top arch frame.

[0009] As a further improvement, the debris at the bottom of the tunnel is first cleared, and then the side arch frames, top arch frames and invert arch frames of the same ring are assembled to form a ring-shaped arch frame support structure.

[0010] As a further improvement, an inverted arch pad that can directly support the bottom wall of the tunnel is laid to form a traffic pavement structure, wherein the inverted arch frame is located in the arch frame avoidance space below the inverted arch pad.

[0011] As a further improvement, after the cantilever tunnel boring machine has advanced one stroke, the invert pads that have passed behind the cantilever tunnel boring machine are removed and then laid in front of the cantilever tunnel boring machine as needed to continuously connect the road surface structure.

[0012] As a further improvement, after the arch support structure is assembled, the slag between the front and rear arches at the bottom of the tunnel is flattened to directly form a passable pavement structure, or the slag between the front and rear arches at the bottom of the tunnel is flattened and invert pads are laid on the slag to form a passable pavement structure.

[0013] As a further improvement, after the boom type tunnel boring machine has excavated forward a stroke, the debris in the rear area through which the boom type tunnel boring machine has passed is cleared.

[0014] As a further improvement, before assembling the invert arch frame, the cantilever tunnel boring machine retreats a set distance to make room for the assembly of the invert arch frame.

[0015] As a further improvement, the set distance refers to the distance when the cantilever tunnel boring machine retreats to the point where the front end of its blade is flush with the front end of the road surface structure.

[0016] The present invention is a pioneering invention, and has the following beneficial effects: the arch support structure assembled during the construction process is a complete and stronger annular support structure, which can effectively improve the construction safety. Moreover, the present invention also adds a traffic pavement structure during the construction process. After the inverted arch frame is assembled, the traffic pavement structure can be used for the cantilever tunneling machine to pass normally, protect the inverted arch frame from being damaged, and ensure the stability of the arch support structure.

[0017] To achieve the above object, the technical solution of the inverted arch pad provided by the present invention is: An inverted arch pad comprises a top plate and a vertical support. The top of the top plate is provided with a passage surface for a cantilever type tunnel boring machine to pass through. The vertical support is used to fit with the bottom wall of the tunnel to support the top plate. An arch frame avoidance space for avoiding the inverted arch frame is provided below the top plate.

[0018] As a further improvement, the inverted arch pad is composed of at least two split pads that can be laterally spliced ​​and separated, each split pad includes the top plate, uprights and arch frame avoidance space, the uprights are upright plates and are arranged around the top plate, wherein the uprights at the two longitudinal ends constitute the end plates of the split pad, and the uprights at the two lateral sides constitute the side plates of the split pad.

[0019] As a further improvement, the side panel on at least one side is an integrated plate-like structure, and a slot is provided on the side panel for entering a single arch frame corresponding to the number of arch frames that the arch pad can avoid, and the space in the slot constitutes the arch frame avoidance space.

[0020] As a further improvement, the longitudinal width of the inverted arch pad is sufficient to avoid more than two inverted arch frames.

[0021] The present invention is a pioneering invention, and has the following beneficial effects: the inverted arch pad provided by the present invention can be used in front of a cantilever type tunnel boring machine to protect the inverted arch frame in front of the cantilever type tunnel boring machine. Specifically, after the inverted arch frame is assembled, the inverted arch pad is laid, and the inverted arch pad can be used for the cantilever type tunnel boring machine to pass normally, protect the inverted arch frame from being damaged, and ensure the stability of the arch frame support structure.

[0022] To achieve the above-mentioned purpose, the technical solution of the assembled pavement structure provided by the present invention is: An assembled pavement structure comprises a plurality of inverted arch pads arranged in a front-to-back manner, wherein the inverted arch pads comprise a top plate and upright supports, wherein the top of the top plate comprises a passage surface for a cantilevered tunnel boring machine to pass through, the upright supports are used to fit with a tunnel bottom wall to support the top plate, and an arch frame avoidance space for avoiding an inverted arch frame is provided below the top plate.

[0023] As a further improvement, the inverted arch pad is composed of at least two split pads that can be laterally spliced ​​and separated, each split pad includes the top plate, uprights and arch frame avoidance space, the uprights are upright plates and are arranged around the top plate, wherein the uprights at the two longitudinal ends constitute the end plates of the split pad, and the uprights at the two lateral sides constitute the side plates of the split pad.

[0024] As a further improvement, the side panel on at least one side is an integrated plate-like structure, and a slot is provided on the side panel for entering a single arch frame corresponding to the number of arch frames that the arch pad can avoid, and the space in the slot constitutes the arch frame avoidance space.

[0025] As a further improvement, the longitudinal width of the inverted arch pad is sufficient to avoid more than two inverted arch frames.

[0026] The present invention is a pioneering invention, and has the following beneficial effects: the inverted arch pad provided by the present invention can be used in front of a cantilever type tunnel boring machine to protect the inverted arch frame in front of the cantilever type tunnel boring machine. Specifically, after the inverted arch frame is assembled, the inverted arch pad is laid, and the inverted arch pad can be used for the cantilever type tunnel boring machine to pass normally, protect the inverted arch frame from being damaged, and ensure the stability of the arch frame support structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A front view of a cantilever tunneling machine used in an embodiment of a tunneling construction method of a cantilever tunneling machine in the present invention; Figure 2 for Figure 1 A top view of the medium boom roadheader; Figure 3 It is a schematic diagram of an embodiment of the cantilever tunnel boring machine excavation construction method of the present invention when the side arch and the top arch are hung (part of the arch support structure is hidden); Figure 4 It is a schematic diagram of the coordination relationship between the inverted arch pad and the arch support structure used in the embodiment of the cantilever type tunnel boring machine tunneling construction method of the present invention; Figure 5 for Figure 4 Schematic diagram of the structure of the middle arch pad.

[0028] Description of reference numerals: 1. Cutting head; 2. Cantilever; 3. Arch grabbing device; 4. First mechanical arm; 5. Sliding platform; 6. Folding arm crane; 7. Conveyor; 8. Hydraulic system; 9. Rear support; 10. Electrical system; 11. Crawler walking mechanism; 12. Shovel board; 13. Slag cleaning device; 14. Second mechanical arm; 15. Third mechanical arm; 100. Arch frame supporting structure; 101. Top arch frame; 102. Side arch frame; 103. Inverted arch frame; 200. Inverted arch pad; 201. Split pad; 202. Top plate; 203. Vertical plate. DETAILED DESCRIPTION

[0029] In order to solve the problem of low safety of cantilevered tunnel boring machines in soft rock geological construction, the basic technical concept of the present invention is to timely assemble a ring-shaped arch support structure in front of the cantilevered tunnel boring machine to play a timely support role. At the same time, in order to prevent the cantilevered tunnel boring machine from damaging the inverted arch frame when it moves forward, before the cantilevered tunnel boring machine moves forward to start the next stroke of tunneling work, a protective inverted arch frame and a road surface structure for the cantilevered tunnel boring machine to move forward are laid, and the cantilevered tunnel boring machine moves along the road surface structure to continue the next stroke of work.

[0030] The present invention is further described in detail below in conjunction with embodiments.

[0031] Specific embodiments of the cantilever type tunnel boring machine tunneling construction method provided by the present invention: The cantilever tunneling machine used in the tunneling construction method provided in this embodiment is as follows: Figure 1 and Figure 2 As shown, its structure is basically consistent with the prior art. Specifically, it includes a chassis with a crawler walking mechanism 11, a cantilever 2 that can swing up and down and left and right is provided on the chassis, a cutting head 1 is provided at the end of the cantilever 2, and a cutting tooth for rock breaking is installed on the cutting head 1. A loading mechanism is also provided on the chassis, which includes a shovel board 12 located at the front end and a conveyor 7 extending forward and backward. The conveyor 7 can be a scraper conveyor. The shovel board 12 is provided with two scraping wheels. The scraping wheels rotate to collect the debris at the bottom of the tunnel and send it to the conveyor 7, and the conveyor 7 continues to transfer it backward. The rear end of the cantilever type tunnel boring machine is also provided with a rear support 9. During the process of excavating and breaking rocks by the front cutting head 1, the rear support 9 can be lowered for support.

[0032] The cantilever tunnel boring machine is also provided with an arch frame installation mechanism. During the construction process, the arch frame installation mechanism can deliver the arch frame to the assembly position, and the installation of the arch frame is completed by manual cooperation. Specifically, the arch frame installation mechanism includes three mechanical arms spaced laterally, namely, a first mechanical arm 4 located in the center, and a second mechanical arm 14 and a third mechanical arm 15 located on the left and right sides of the first mechanical arm 4. The three mechanical arms are multi-degree-of-freedom mechanical arms that can swing up and down and left and right, and the three mechanical arms are provided with an arch grabbing device 3. The arch grabbing device 3 can clamp the arch frame. Specifically, the arch grabbing device for clamping the arch frame configured by the arch frame trolley in the prior art can be used. The three mechanical arms are all installed on the sliding platform 5, and slide forward with the sliding platform 5 to deliver the arch frame to a suitable position. The sliding platform 5 can also adopt the existing technology, such as the secondary sliding platform disclosed in the patent document with application publication number CN113833486A, which will not be described in detail here.

[0033] The cantilever type tunnel boring machine is also provided with a lifting device, which includes a folding arm crane 6 installed on the sliding platform 5. The folding arm crane 6 can lift the materials sent from the rear and transport them forward, thereby reducing the labor intensity of the personnel.

[0034] Naturally, the boom-type roadheader further includes a hydraulic system 8 and an electrical system 10 for providing power to various devices or equipment.

[0035] like Figure 3 and Figure 4As shown, during construction, the support structure assembled in this embodiment is a ring-shaped arch support structure 100, that is, a support structure including a top arch frame 101, a side arch frame 102 and an inverted arch frame 103. Different from the prior art, this embodiment involves a process of assembling the inverted arch frame 103 in front of the cantilever type tunnel boring machine. Analysis of the formed arch support structure 100 shows that the arch support structure 100 is a complete ring structure, which can form a circumferential all-round support structure. For soft surrounding rock geology, this support structure is more stable, which naturally improves the safety of the operation.

[0036] Since the arch support structure 100 is located forward, in order to prevent the crawler walking mechanism 11 from crushing the inverted arch 103 when the cantilever tunneling machine moves forward, the present embodiment also requires laying a traffic pavement structure in front of the cantilever tunneling machine. The cantilever tunneling machine moves forward along the traffic pavement structure, thereby playing a role in protecting the inverted arch 103.

[0037] From a holistic perspective, the construction method can be divided into three steps. First, a ring-shaped arch support structure 100 is assembled in front of the cantilever tunnel boring machine, and then a traffic pavement structure is laid to protect the invert arch 103. After that, the cantilever tunnel boring machine continues to advance along the laid traffic pavement structure to start the next journey of excavation.

[0038] As a specific implementation method of assembling the arch frame support structure 100, in order to further improve the construction safety, before removing the slag at the bottom of the tunnel, the top arch frame 101 and the side arch frame 102 can be assembled first, and then an inverted U-shaped arch frame support structure can be initially formed to prevent slag from falling from the top and both sides of the tunnel and injuring the workers during the slag removal operation and the assembly of the inverted arch frame 103. According to the actual situation, at least one or more top arch frames 101 and side arch frames 102 are assembled first. Then, the slag at the bottom of the tunnel is removed, and the inverted arch frame 103 is assembled in front of the cantilevered tunnel boring machine, so that the inverted arch frame 103, the side arch frames 102 and the top arch frame 101 are assembled into a ring.

[0039] As another feasible implementation method of assembling the arch frame support structure 100, during construction, the debris at the bottom of the tunnel is first cleared. After the debris at the bottom of the tunnel is cleared, the inverted arch frame 103, the side arch frame 102 and the top arch frame 101 of the same ring are assembled to directly form a ring-shaped arch frame support structure.

[0040] In the above two embodiments, in order to better protect the inverted arch frame 103, in actual construction, the following method can be adopted: Figure 3 and Figure 4The assembled pavement structure is formed by splicing the inverted arch pads 200. The inverted arch pads 200 are supported by the tunnel bottom wall, and the top end is higher than the inverted arch frame 103 to cover the inverted arch frame 103 in the arch frame avoidance space inside, so that the cantilevered tunnel boring machine passes through the top end of the inverted arch pads 200.

[0041] Specifically, for the invert pad 200, if Figure 4 and Figure 5 As shown, basically, it includes a top plate 202 and a vertical support, the vertical support is used to support the tunnel bottom wall to support the top plate 202, and can be a plate-shaped vertical plate 203 or a columnar support column. In terms of material, the invert pad 200 can be made of a harder metal material or engineering plastic.

[0042] In order to save the inverted arch pad 200 and reduce the cost, in this embodiment, the inverted arch pad 200 can be reused. Specifically, after the cantilevered tunnel boring machine passes, the inverted arch pad 200 located behind the cantilevered tunnel boring machine can be removed and laid in front of the cantilevered tunnel boring machine (specifically in front of the crawler walking mechanism 11) as needed. Of course, in other embodiments, more inverted arch pads 200 can also be prepared at one time, paved in the tunnel during construction, and removed during the subsequent pouring of concrete.

[0043] In order to facilitate the disassembly, assembly and transportation of the inverted arch pad 200, the inverted arch pad 200 can be a split structure formed by splicing. Figure 4 and Figure 5 As shown, the inverted arch pad 200 is composed of four split pads 201 that can be spliced ​​and separated, and each split pad 201 is an independent part, including a top plate 202, a vertical plate 203, and an arch frame shielding space below the top plate 202. At this time, the volume of each split pad 201 will not be too large, which is convenient for disassembly and transportation. For each split pad 201, the vertical plates 203 are respectively arranged around the top plate 202, wherein the vertical plates 203 at the two ends in the longitudinal direction constitute the end plates of the split pad 201, and the vertical plates 203 at the two sides in the transverse direction constitute the side plates of the split pad 201. Similarly, for the curved tunnel bottom wall, the shape of each split pad 201 should be adaptively designed to ensure that each split pad 201 can be smoothly spliced.

[0044] Considering the supporting strength of the vertical plate 203, the side plate is preferably an integrated structure, and the side plate also needs to meet the requirement of not interfering with the invert arch frame 103. More specifically, Figure 5As shown, in the transverse two side plates, at least one side plate should be provided with a slot, so that when the inverted arch pad 200 is laid, the inverted arch frame 103 can just enter the slot, and the internal space of the slot corresponds to the arch frame avoidance space. Preferably, the longitudinal width of the inverted arch pad 200 is sufficient to cover and avoid more than two inverted arch frames 103, so that the number of inverted arch pads 200 will not be too large. Correspondingly, two slots are also provided, and the two slots correspond to each single inverted arch frame 103, so that part of the side plate can also be located between two adjacent inverted arch frames 103 in the longitudinal direction. In other embodiments, the inverted arch pad 200 can also only cover and avoid one arch frame at a time, and accordingly, only one slot can be provided. In the optimization scheme, the bottom surface of the slot (because the slot opening of the slot is facing downward, the bottom surface of the slot is actually the surface at the top) can contact the inverted arch frame 103, and the inverted arch frame 103 can also play a certain supporting role.

[0045] In other embodiments, the side panels may also be distributed separately and at intervals, that is, there are more than two side panels and they are arranged at intervals in the longitudinal direction, and the space between two adjacent side panels can accommodate the inverted arch frame 103.

[0046] Of course, for a tunnel with a small diameter, the size of the invert arch support structure is relatively small, and the required invert arch pad 200 will not be too large. In this case, an integrated invert arch pad 200 can be selected.

[0047] As another embodiment of assembling the arch support structure 100, during construction, the slag at the bottom of the tunnel may not be completely removed. The staff uses tools to push the slag at the bottom of the tunnel to expose the bottom wall of the tunnel, and then flattens the slag between the front and rear inverted arch frames 103 (similar to ballasted track), and the slag can be used as support. Specifically, there are two situations at this time. The first situation is that there is a large amount of slag remaining at the bottom of the tunnel. At this time, the slag can be directly paved to form a passable road surface structure, and the cantilevered tunnel boring machine passes through the slag. In this process, although the crawler walking mechanism 11 will partially press over the inverted arch frame 103, the cantilevered tunnel boring machine is still mainly supported by the slag. The second situation is that the amount of slag remaining at the bottom of the tunnel is small and is not enough to be paved to form a passable road surface structure. At this time, the inverted arch pad 200 can be laid after the slag is flattened.

[0048] As for the debris remaining at the bottom of the tunnel, after the cantilever tunnel boring machine has advanced one stroke, the debris in the rear area through which the cantilever tunnel boring machine has passed can be cleared.

[0049] In addition, if Figure 3As shown, when assembling the arch frame, the cantilevered roadheader is actually located on the inverted arch pad 200. In order to facilitate the assembly of the arch frame, before assembling the inverted arch frame 103, the cantilevered roadheader can be retreated by a set distance to make room for the assembly position of the inverted arch frame 103. Preferably, the distance of retreat of the cantilevered roadheader satisfies that the front end of its shovel plate 12 is substantially flush with the front end of the most forward inverted arch pad 200. In this way, with the inverted arch pad 200 as a reference, on the one hand, it is not necessary to retreat too far, so that the arch frame can be assembled in time, and at the same time, it can also ensure that the shovel plate 12 can obtain sufficient support from the inverted arch pad 200.

[0050] Of course, in other implementations, the cantilever tunnel boring machine may not retreat, and the oil cylinder configured to control the shovel board 12 may raise the shovel board 12 and assemble the arch frame under the shovel board 12.

[0051] Whenever the top arch frame 101 and the side arch frame 102 are assembled, for a cantilever type tunnel boring machine equipped with an arch frame mounting mechanism, Figure 3 As shown, the mechanical arm of the arch frame installation mechanism (specifically the first mechanical arm 4) can first grasp and support the top arch frame 101, and then hang the left and right side arch frames 102 on the lateral ends of the top arch frame 101 to form an arch frame assembly. The side arch frames 102 can be hung on the two ends of the top arch frame 101 by using pins or ropes to ensure that the side arch frames 102 do not fall and do not interfere with the tunnel wall. The mechanical arm can move forward to deliver the arch frame assembly to the assembly position, and the staff will then fix the side arch frames 102 to the top arch frame 101. In this way, the top arch frame 101 and the side arch frames 102 can be pre-connected to improve construction efficiency. In addition, for the arch frame structure of multiple sections of arch frames, this can also free up other mechanical arms, such as Figure 3 As shown, the third robot arm 15 can also grab a section of the side arch frame 102.

[0052] The cantilever type tunnel boring machine used in this embodiment is also equipped with a slag cleaning device 13. The slag cleaning device 13 includes a multi-degree-of-freedom slag cleaning mechanical arm, and a bucket is provided at the front end of the mechanical arm. The specific structure of the slag cleaning mechanical arm can be consistent with the digging arm configured for the excavator in the prior art. Compared with manual slag cleaning, this can significantly improve the slag cleaning efficiency.

[0053] In addition, the folding arm crane 6 configured on the cantilever tunnel boring machine can also move forward with the sliding platform 5, so that the folding arm crane 6 can lift the arch frame 103 and the arch pad 200 forward, and the staff can receive the arch frame 103 and the arch pad 200 and assist in transporting them to a suitable position for assembly or laying.

[0054] The specific embodiment of the inverted arch pad in the present invention is: The embodiment of the inverted arch pad is the inverted arch pad recorded in the embodiment of the above-mentioned cantilever type tunnel boring machine excavation construction method, which will not be described in detail here.

[0055] Specific embodiments of the assembled pavement structure of the present invention: The embodiment of the assembled pavement structure is the assembled pavement structure formed by splicing inverted arch gaskets recorded in the embodiment of the above-mentioned cantilever tunneling construction method, which will not be described in detail here.

[0056] 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 cantilever type tunnel boring machine excavation construction method, characterized in that: The following steps are involved: ① Assemble the arch support structure into a ring in front of the cantilever tunnel boring machine; ② Lay the traffic pavement structure to protect the invert arch; ③ The cantilever tunnel boring machine continues to excavate forward along the laid traffic pavement structure.

2. The cantilever type tunnel boring machine excavation construction method according to claim 1 is characterized in that: First, assemble the side arch and top arch frames in front of the cantilevered TBM, then clear the debris at the bottom of the tunnel, and then assemble the invert arch frame to form a ring with the side arch and top arch frames.

3. The cantilever type tunnel boring machine excavation construction method according to claim 1, characterized in that: First, remove the debris at the bottom of the tunnel, and then assemble the side arch frames, top arch frames and invert arch frames of the same ring to form a ring-shaped arch frame support structure.

4. The cantilever type tunnel boring machine excavation construction method according to claim 2 or 3, characterized in that: An inverted arch pad that can directly support the bottom wall of the tunnel is laid to form a traffic pavement structure, wherein the inverted arch frame is located in the arch frame avoidance space below the inverted arch pad.

5. The cantilever type tunnel boring machine excavation construction method according to claim 4 is characterized in that: After the cantilever tunnel boring machine has advanced one stroke, the invert pads that have passed behind the cantilever tunnel boring machine are removed and then laid in front of the cantilever tunnel boring machine as needed to continuously connect the road surface structure.

6. The cantilever type tunnel boring machine excavation construction method according to claim 1, characterized in that: After the arch support structure is assembled, the slag between the front and rear arches at the bottom of the tunnel is leveled to directly form a passable pavement structure, or the slag between the front and rear arches at the bottom of the tunnel is leveled and an invert pad is laid on the slag to form a passable pavement structure.

7. The cantilever type tunnel boring machine excavation construction method according to claim 6 is characterized in that: After the boom tunnel boring machine has excavated forward a stroke, the debris in the rear area through which the boom tunnel boring machine has passed is cleared.

8. The cantilever type tunnel boring machine excavation construction method according to any one of claims 1 to 3, 6 and 7, characterized in that: Before assembling the invert arch frame, the cantilever tunnel boring machine retreats a set distance to make room for the assembly of the invert arch frame.

9. The cantilever type tunnel boring machine excavation construction method according to claim 8, characterized in that: The set distance refers to the distance when the cantilever tunnel boring machine retreats to the point where the front end of its blade is flush with the front end of the road surface structure.

10. An inverted arch pad, characterized in that: It includes a top plate and a vertical support. The top of the top plate is provided with a passage surface for a cantilevered tunnel boring machine to pass through. The vertical support is used to fit with the bottom wall of the tunnel to support the top plate. An arch frame avoidance space for avoiding an invert arch frame is provided under the top plate.

11. The inverted arch pad according to claim 10, characterized in that: The inverted arch pad is composed of at least two split pads that can be laterally spliced ​​and separated. Each split pad includes the top plate, vertical supports and arch frame avoidance space. The vertical supports are vertical plates and are arranged around the top plate. The vertical supports at the two longitudinal ends constitute the end plates of the split pad, and the vertical supports at the two lateral sides constitute the side plates of the split pad.

12. The inverted arch pad according to claim 11, characterized in that: The side plate on at least one side is an integrated plate-like structure, and is provided with a slot corresponding to the number of inverted arch frames that the inverted arch pad can avoid and for a single inverted arch frame to enter, and the space in the slot constitutes the arch frame avoidance space.

13. The inverted arch pad according to any one of claims 10 to 12, characterized in that: The longitudinal width of the inverted arch pad is sufficient to avoid more than two inverted arch frames.

14. An assembled pavement structure, characterized in that: It comprises a plurality of inverted arch pads which are arranged front to back and spliced ​​together, wherein the inverted arch pad is the inverted arch pad in any one of items 10-13.

Images