Arrangement for laying tunnel bottom ring reinforcement and method of construction

Abstract

The application discloses a device for laying tunnel bottom ring-shaped reinforcement and a construction method, and relates to the technical field of tunnel construction. The device comprises a walking trolley, a main frame and a transverse trolley. The main frame is sleeved on the walking trolley and is driven to lift by a hydraulic cylinder, and the bottom of the main frame is connected with an arc-shaped track at both ends. The transverse trolley is connected with the arc-shaped track in a rolling mode, and the bottom of the transverse trolley is detachably connected with a mounting plate. The mounting plate is provided with an array of openings, and a double-C-shaped comb split elastic sheet with elastic flaring deformation capacity is arranged in the openings, and is used for limiting double rows of ring-shaped reinforcements simultaneously. A reinforcement clamping head is hung on the bottom of the mounting plate. Temporary fixing components are symmetrically distributed at both ends of the arc-shaped track, and are used for locking the end portions of the reinforcements. The double-C-shaped comb split elastic sheet is combined with the temporary fixing components, the automatic spacing combing and the suspended positioning of the double rows of ring-shaped reinforcements are realized, the automatic demolding is realized based on the linkage of the limiting mechanism and the hydraulic cylinder, and the problems of the spatial interference of the double-layer reinforcement net and the combing structure deadlock in the closed space are effectively solved.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and in particular to a device and construction method for laying circumferential reinforcing bars at the bottom of a tunnel. Background Technology

[0002] In mountain tunnel engineering, the invert is a key load-bearing structure that withstands the pressure from the tunnel sidewalls and bottom surrounding rock. To ensure structural strength, the reinforcement of the invert is usually designed as a double-layer rigid steel mesh consisting of two rows of circumferential main bars and longitudinal distribution bars, and the specifications have strict precision requirements for the spacing of the bars and the vertical spacing between the upper and lower layers.

[0003] Currently, traditional invert arch reinforcement binding mainly relies on manual in-situ binding at the bottom of the excavated pit. This method has significant drawbacks: firstly, the base environment is harsh, and the working space is restricted by the overhead trestle, requiring workers to bend over or even squat for extended periods, resulting in extremely high labor intensity; secondly, the spacing between the double-layer reinforcement mesh is mainly maintained by manually welding stirrups, which is prone to deformation and misalignment during construction and subsequent concrete pouring, leading to uncontrolled spacing between the upper and lower layers of reinforcement. With the advancement of tunnel construction mechanization, the industry has begun to adopt suspended mechanized binding technology to replace traditional manual in-situ binding. Existing technology, combined with practical engineering applications, has revealed that existing suspended reinforcement equipment generally faces the following serious technical bottlenecks that severely restrict construction efficiency in the temporary fixing of reinforcement and the lowering of the formed mesh: Firstly, the efficiency of temporary fixing of the reinforcement ends is low. During the suspended sorting process, the two ends of the ring reinforcement need to be temporarily anchored to maintain tension. Existing equipment mostly uses spiral clamps, pins, or manual binding wire for end fixing. This type of single-point independent operation is cumbersome and time-consuming, severely slowing down the reinforcement placement rhythm when dealing with the large volume and dense double-row reinforcement in tunnels. Secondly, there is the problem of asynchronous lowering of the heavy steel mesh. After the double-layer steel mesh is tied and formed in mid-air, its overall weight is enormous. When lowering the steel mesh to the foundation, all temporary fixations at the ends of the circumferential reinforcement must be released. In existing technologies, due to the lack of a coordinated group-release mechanism, construction workers can only release the fixation points one by one. This asynchronous release process is not only extremely time-consuming but also leads to extremely dangerous stress concentration: the side released first will tilt and fall, and the unreleased fixation points will bear the tearing force of the entire steel mesh, easily causing the formed steel mesh to twist and deform, lose design accuracy, and even cause safety accidents; moreover, the bottom reinforcement comb structure also faces the problem of detachment, resulting in reduced construction efficiency.

[0004] In summary, how to develop a temporary fixing mechanism that can quickly lock the ends of circumferential reinforcing bars and achieve instantaneous and synchronous mass placement when large-tonnage steel mesh is lowered, as well as design a combing mechanism that can be easily detached, in order to overcome the efficiency bottleneck of the suspension binding process, are the technical problems that urgently need to be solved in the field of tunnel invert arch construction. Summary of the Invention

[0005] The present invention aims to provide a device and construction method for laying circumferential reinforcing bars at the bottom of a tunnel, in order to solve the technical problems in the prior art that exist in the process of suspending and binding double-layer reinforcing mesh of invert arch, such as time-consuming end fixing, low efficiency caused by asynchronous lowering and release, deformation of the mesh frame, and inconvenience of disengaging the combing mechanism.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A device for laying circumferential reinforcing bars at the bottom of a tunnel, comprising: Mobile trolley; The main frame is mounted on a traveling trolley, and a hydraulic cylinder for driving the overall lifting and lowering of the main frame is connected between the main frame and the traveling trolley; arc-shaped tracks are respectively connected to both ends of the bottom of the main frame. A transverse trolley is rotatably connected to the arc-shaped track; a mounting plate is detachably connected to the bottom of the transverse trolley. The mounting plate has multiple openings in an array. Each opening contains a pair of combing springs with a double C-shaped structure, which are used to simultaneously limit the upper and lower double rows of annular steel bars. The combing springs have elastic flaring deformation capability. The mounting plate is also provided with a limiter corresponding to each opening. At the bottom of the mounting plate, corresponding to each opening, two steel bar clamps are suspended by two flexible suspension members. A temporary fixing component is provided, which is symmetrically distributed at both ends of the arc-shaped track, and each end is provided with two parallel sets, which are used to lock the two ends of the upper and lower double-row ring steel bars respectively.

[0007] Preferably, each comb spring on the mounting plate is rotatably connected to a limiting mechanism via a damping shaft; the limiting mechanism has a locking position and a releasing position; the end of the limiting mechanism away from the rotating shaft is provided with two protrusions. When in the locking position, the two protrusions are respectively embedded in the gap between the outer wall of the comb spring and the inner wall of the corresponding opening to restrict the comb spring from flaring outward; when in the releasing position, the limiting mechanism rotates out of the gap to restore the degree of freedom of the comb spring to flare outward.

[0008] Preferably, the temporary fixing component includes a base, on which limit grooves are arrayed, the limit grooves being correspondingly provided with openings on the mounting plate, and the base having cavities adjacent to each limit groove. A pressure rod is hinged inside the cavity, and a pressure block with a corresponding limiting groove is fixedly connected to the pressure rod through a connector; A ratchet is coaxially fixed on the hinge shaft of the pressure rod, and a first return spring is connected between the pressure rod and the side wall of the base. The first return spring provides a biasing elastic force to the pressure rod to make it rotate and drive the pressure block to lift upward.

[0009] Preferably, a rotating shaft is provided inside the base along its length; a pawl is fixedly connected to each ratchet on the rotating shaft, and the pawl engages with the tooth groove of the corresponding ratchet to unidirectionally restrict the lifting of the pressure rod.

[0010] Preferably, a reset handle is connected to the end of the rotating shaft extending out of the base, and a second reset spring is connected between the reset handle and the base to provide a rotational holding force to the reset handle.

[0011] Preferably, a first flexible pad is attached to the inner bottom wall of the limiting groove; a second flexible pad is connected to the side of the pressure block near the limiting groove, and the working surface of the second flexible pad is an inwardly concave arc surface structure.

[0012] Preferably, the two sets of temporary fixing components that are parallel at each end include a first temporary fixing component connected to the end of the arc-shaped track, and a second temporary fixing component connected to the main frame by a bracket; the bracket is vertically fixed to the side of the main frame, and the top horizontal elevation of the first temporary fixing component is lower than the bottom horizontal elevation of the second temporary fixing component.

[0013] Preferably, the top surface of the transverse trolley is equipped with a follow-up rebar storage rack; the bottom surface of the support is equipped with a fixed rebar storage rack, which is located in the area above the first temporary fixing component. The two are spatially staggered to form an avoidance channel for the rebars in the fixed rebar storage rack to cross and intersect laterally.

[0014] Preferably, the outer side of the wheels of the traveling trolley is provided with a marking plate for aligning with the construction guide line; two sets of hydraulic cylinders are arranged symmetrically in the longitudinal direction between the traveling trolley and the main frame.

[0015] The present invention also provides a construction method for laying circumferential reinforcement at the bottom of a tunnel, using the laying device for circumferential reinforcement at the bottom of a tunnel as described above, and including the following steps: S1. The traveling trolley is aligned and positioned according to the preset markings, and the hydraulic cylinder extends to drive the main frame to rise to the predetermined construction height; the ends of the double-row ring steel bars are respectively placed in the corresponding two steel bar clamps; S2. The transverse trolley travels along the arc-shaped track to the opposite end of the track; S3. Simultaneously transfer the double-row ring steel bars into a pair of comb-shaped spring clips of the double C shape, and rotate the limiting mechanism to the locking position to restrict the opening of the spring clips; S4. Place one end of the double-row ring steel bar into the limiting groove of the two sets of temporary fixing components on the opposite side and press down the pressure block to make the pawl lock the ratchet in one direction, thereby locking the ends of the two steel bars independently in the corresponding limiting groove. S5. The transverse trolley returns to the starting point to perform sorting operations on the double-row steel bars. After returning to the starting point, the other end of the double-row ring steel bars is fixed in the two sets of temporary fixing components on the starting point side. S6. The transverse trolley drives the installation plate to move in fixed lengths in stages. Each time it moves to the position, the longitudinal reinforcement binding operation is carried out, and the interlayer welding operation of the stirrups is carried out at the same time. During the process, the installation plate provides the positioning and limiting function to fix the spacing of the longitudinal reinforcement. S7. The hydraulic cylinder retracts to drive the main frame to descend as a whole, and the steel mesh is lowered to the ground. The reset handles on both sides are turned to make the shaft rotate, the pawl disengages from the ratchet, and each pressure bar rotates synchronously under the action of the first reset spring and drives the pressure block to lift up, so as to release the ends of the double row of steel bars in a synchronous manner. S8. Rotate the limiting mechanism to the release position; the hydraulic cylinder extends for the second time to drive the main frame to rise, and the combing spring is forced to open outward under the obstruction of the steel bars, so as to realize the automatic separation of the combing mechanism from the double-layer steel mesh.

[0016] The effects described in the invention are merely those of the embodiments, and not all the effects of the invention. The above technical solutions have the following advantages or beneficial effects: 1. This invention integrates a ratchet, pawl, and double return spring linkage mechanism within a temporary fixing component. During the mesh installation phase, the operator only needs to press down on the pressure block, and the pawl can lock the ratchet in one direction for instantaneous locking. During the lowering phase of the heavy mesh frame, turning the return handle causes the shaft to deflect, and all the pawls on the same base can simultaneously disengage, causing the pressure bar to lift instantly under the biasing force of the first return spring. This structure ensures that the ends of the reinforcing bars in the same row disengage synchronously, eliminating the uneven load tearing deformation of the mesh frame caused by asynchronous release.

[0017] 2. The device employs double C-shaped combing springs with elastic flaring capability, coupled with a damping limiting mechanism. During the suspension of the steel mesh, the limiting mechanism is in the locking position, using physical interference to limit the deformation of the springs to bear the weight of the reinforcing bars. After the steel mesh is placed on the ground, the limiting mechanism is rotated to the release position. When the hydraulic cylinder rises a second time, the reverse resistance force of the formed steel mesh forces the combing springs to open outward. This structure achieves the conversion between rigid load-bearing and elastic demolding based on the switching of the mechanism's position, breaking the structural deadlock problem faced by traditional hooked molds in confined spaces.

[0018] 3. By arranging the first and second temporary fixing components at different heights and placing the fixed rebar storage rack directly above the first temporary fixing component, an unobstructed passageway is constructed in physical space for the lower longitudinal rebar to pass through laterally. This layout decouples the path interference between the surface layer and the bottom layer rebar supply, ensuring that the insertion operation of the bottom layer grid is not affected by the obstruction of the formed surface layer grid.

[0019] 4. The mounting plate mounted under the transverse trolley has an array of double C-shaped structures. This structure achieves equidistant spacing of the circumferential steel bars in the horizontal direction. At the same time, through the upper and lower limit of the single plate double C cavity, a rigid distance constraint is applied to the upper and lower rows of steel bars in the vertical direction. Physical force ensures the absolute alignment of the double steel mesh layers and the constant standard layer spacing.

[0020] 5. A first flexible pad is attached to the bottom wall of the limiting groove, while a second flexible pad with an inwardly concave arc surface is provided on the bottom surface of the pressure block. The double flexible pad and arc surface design not only increase the contact area with the threaded surface of the reinforcing bar, significantly improving the frictional self-locking force under high tension, but also effectively prevent the rigid metal pressure block from crushing the anti-corrosion layer or ribs on the surface of the reinforcing bar.

[0021] 6. The rebar clamping head is connected to the bottom of the mounting plate via flexible suspension components such as chains. In the initial stage of combing and traction, the flexible suspension structure allows for a certain degree of multi-degree-of-freedom swaying at the ends of the rebars, which can adaptively accommodate the slight deformation or unevenness of the circumferential rebars caused by pre-bending, reducing the risk of mechanical jamming.

[0022] 7. Two sets of hydraulic cylinders are symmetrically arranged longitudinally between the traveling trolley and the main frame. The symmetrical layout of the dual cylinders can effectively overcome the off-center load and overturning moment caused by single-point drive, and greatly improve the structural stability of the main frame when suspending heavy steel bars for overall lifting.

[0023] 8. The alignment marking plates set on the outside of the wheels of the traveling trolley provide a precise visual reference for the trolley to travel on the rough and undulating arch base, ensuring that the trolley travels straight without deviating, thereby ensuring that the lowered steel mesh can be accurately aligned with the previous cycle of formed grid at the longitudinal overlap. Attached Figure Description

[0024] Figure 1 This is the front view of the present invention; Figure 2 for Figure 1 A magnified view of a portion of region A in the middle; Figure 3 This is a right view of the present invention; Figure 4 for Figure 3 A magnified view of a portion of region A in the middle; Figure 5 The overall structure of the present invention Figure 1 ; Figure 6 for Figure 5 A magnified view of a portion of region A in the middle; Figure 7 The overall structure of the present invention Figure 2 ; Figure 8 This is a cross-sectional view of the internal connection relationship of the temporary fixing component of the present invention.

[0025] The components include: 1. Traveling trolley; 101. Hydraulic cylinder; 102. Marking alignment plate; 2. Main frame; 21. Arc track; 3. Lateral trolley; 31. Follow-up rebar storage rack; 4. Mounting plate; 41. Combing spring; 42. Limiting mechanism; 421. Protrusion; 43. Rebar clamping head; 5. Temporary fixing assembly; 5a. First temporary fixing assembly; 5b. Second temporary fixing assembly; 51. Base; 52. Limiting groove; 521. First flexible pad; 53. Pressure block; 531. Second flexible pad; 54. Connector; 55. Pressure rod; 551. Ratchet; 552. First return spring; 56. Rotating shaft; 561. Pawl; 57. Return handle; 571. Second return spring; 6. Bracket; 7. Fixed rebar storage rack. Detailed Implementation

[0026] To clearly illustrate the technical features of this solution, the invention will be described in detail below through specific implementation methods and in conjunction with the accompanying drawings.

[0027] Example 1 See Figures 1 to 8 This embodiment proposes a device for laying circumferential reinforcement at the bottom of a tunnel. Structurally, it primarily comprises a traveling trolley 1. In actual tunnel construction scenarios, the outer side of the wheels or the edge of the chassis of the traveling trolley 1 is specially equipped with alignment marking plates 102. During construction, workers pre-lay guide lines on the ground, and the trolley wheels move along these guide lines, aligning with the marking plates in real time. This physical reference prevents the trolley from veering off course, ensuring high-precision alignment and overlap of the two sections of poured reinforcement mesh in the longitudinal direction.

[0028] Above the traveling trolley 1, a main frame 2 is mounted. A hydraulic cylinder 101 connects the main frame 2 to the traveling trolley 1, used to drive the overall lifting and lowering of the main frame 2. Specifically, two sets of four hydraulic cylinders are symmetrically arranged longitudinally (i.e., in the direction of travel) between the traveling trolley 1 and the main frame 2. Due to the heavy weight of the integrally formed double-layer steel mesh frame, the symmetrical arrangement of the four cylinders greatly improves the stability of the main frame 2 under heavy load suspension; furthermore, the lifting and lowering of these four hydraulic cylinders is uniformly controlled by a built-in synchronous controller, ensuring that the main frame 2 will not overturn due to uneven load during lifting and lowering, facilitating comfortable chest-high binding by workers below.

[0029] To facilitate the traction and arrangement of the reinforcing bars, an arc-shaped track 21 is connected to each end of the bottom of the main frame 2. A transverse trolley 3 is rolled within the arc-shaped track 21. Driven by a power source, the transverse trolley 3 can slide along the track from one side of the tunnel to the other. A core combing component mounting plate 4 is detachably connected to the bottom of the transverse trolley 3. The mounting plate 4 is detachable and can be replaced with two combing springs 41 with different positioning zone spacings according to actual construction needs. Alternatively, a mounting plate with a suitable reinforcing bar clamping head 43 can be selected based on the diameter of the reinforcing bars. Multiple openings are arrayed on the mounting plate 4. In the detailed structure, a pair of combing springs 41 are installed in each opening. To simultaneously limit the upper and lower double rows of annular reinforcing bars, this combing spring 41 is designed as a double C-shaped structure. The upper and lower C-shaped cavities of this double C-shaped spring can simultaneously clamp one upper main reinforcing bar and one lower main reinforcing bar, ensuring not only the horizontal spacing but also the vertical alignment of the two rows of reinforcing bars.

[0030] Furthermore, since the combing spring 41 is made of elastic material, it has the ability to expand and deform elastically, which is designed for subsequent demolding. However, in the initial stage of combing and pulling, most of the steel bar is dragging on the ground, and the spring needs to withstand a great downward force. At this time, the steel bar is very easy to fall off due to the force causing it to open. To this end, the mounting plate 4 is also equipped with a limit function corresponding to each opening. Specifically, a limit mechanism 42 is rotatably connected to each combing spring 41 via a damping shaft. The limit mechanism 42 has two working states: locking position and releasing position. Two protrusions 421 are provided at the end of the limit mechanism 42 away from the rotating shaft.

[0031] When in the locking position, i.e., during the traction and suspension stress stage, the worker rotates the limiting mechanism, and the two protrusions 421, like wedges, are respectively embedded in the gap between the outer wall of the comb spring 41 and the inner wall of the corresponding opening. This physically restricts the outward flaring deformation of the comb spring 41 from the outside, temporarily fixing it and supporting the reinforcing bar.

[0032] When the mesh is in the release position, i.e., the mesh is ready to be demolded after landing, it is rotated in the opposite direction. The protrusion 421 is rotated out of the gap, and the combing spring 41 regains the freedom to open to the outside. At this time, the main frame 2 is lifted by the hydraulic cylinder, and the combing mechanism will be released.

[0033] To pull steel bars over ten meters long across the span, two flexible suspension members are used at the bottom of the mounting plate 4 for each opening. In this embodiment, two steel bar clamping heads 43 are preferably suspended by chains. The purpose of using flexible chains instead of rigid tie rods is to allow a certain amount of swaying play during the pulling process, preventing the mechanism from jamming or the steel bars from breaking due to rigid force.

[0034] After the reinforcing bars are pulled to one end of the arc-shaped track 21, that end of the reinforcing bar is temporarily fixed. After the transverse combing of the reinforcing bars is completed, the other end of the reinforcing bars needs to be tensioned and locked. This device is equipped with temporary fixing components 5. The temporary fixing components 5 are symmetrically distributed at both ends of the arc-shaped track 21, and each end is provided with two parallel sets, which are used to lock the two ends of the upper and lower double-row ring reinforcing bars respectively. That is, the upper and lower layers of reinforcing bars on one side each have their own fixing components, for a total of four sets on both sides.

[0035] This temporary fixing assembly 5 must not only be able to lock, but also be able to unlock instantly and synchronously. The temporary fixing assembly 5 includes a base 51, on which are arrayed limiting grooves 52 corresponding to the openings of the mounting plate 4. A cavity adjacent to each limiting groove 52 is formed on or inside the base 51. A pressure rod 55 is hinged in the cavity, and a pressure block 53 corresponding to the limiting groove 52 is fixedly connected to the pressure rod 55 via a connector 54. At the same time, a first return spring 552 is connected between the pressure rod 55 and the side wall of the base 51. This spring continuously provides a biasing elastic force to the pressure rod 55, attempting to make it rotate and drive the pressure block 53 to lift upward, thus maintaining the tendency to release.

[0036] To achieve one-way locking and overcome the lifting force of the spring, a ratchet 551 is coaxially fixed on the hinge shaft of the pressure rod 55. A long rotating shaft 56 runs through the base 51 along its length. A pawl 561 is fixedly connected to the rotating shaft 56 at the position corresponding to each ratchet 551. The pawl 561 engages with the tooth groove of the corresponding ratchet 551. When hanging the rebar, the worker places the rebar into the limiting groove 52 and presses down the pressure block 53. The pressure rod 55 rotates, and at this time, the pawl 561 slides unidirectionally across the tooth surface of the ratchet 551, making a clicking sound. Because the pawl 561 unidirectionally restricts the lifting of the pressure rod 55, the pressure block 53 is instantly locked in the pressed state, firmly pressing down the rebar. This action reduces the operation of traditional wire binding, which takes several minutes, to a one-second self-locking process.

[0037] To further protect the reinforcing bars and increase the clamping force, a first flexible pad 521 is attached to the inner bottom wall of the limiting groove 52; a second flexible pad 531 is connected to the side of the pressure block 53 near the limiting groove 52, and the working surface of the second flexible pad 531 is refined into an inwardly concave arc structure. This ensures that the upper and lower flexible pads completely wrap around the reinforcing bars when clamped, and increases the frictional self-locking force.

[0038] To release the multi-ton steel mesh without causing localized deformation, a reset handle 57 is connected to the end of the rotating shaft 56 extending from the base 51. A second reset spring 571, providing rotational holding force, connects the reset handle 57 to the base 51, ensuring that the pawls remain close to the ratchet under normal conditions. When lowering, simply move the reset handle 57; the entire long rotating shaft 56 rotates, forcing all the pawls 561 to simultaneously disengage from the ratchet 551. Once released, each pressure bar 55 instantly and synchronously rotates under the tension of its respective first reset spring 552, simultaneously lifting the entire row of pressure blocks 53. The taut ends of the steel bars are released synchronously.

[0039] The construction of the tunnel invert requires the binding of a double-layer mesh, which easily leads to spatial interference and tangling when inserting longitudinal reinforcing bars. This device solves this problem through ingenious spatial misalignment. The two sets of temporary fixing components 5, which are parallel at each end, are differentiated in terms of spatial height and position: they include a first temporary fixing component 5a connected to the lower end of the curved track 21, and a second temporary fixing component 5b connected to the main frame 2 at a higher elevation via a bracket 6. The bracket 6 is vertically fixed to the side of the main frame 2, so that the top horizontal elevation of the first temporary fixing component 5a is lower than the bottom horizontal elevation of the second temporary fixing component 5b. Correspondingly, the top surface of the transverse trolley 3 is equipped with a follow-up reinforcing bar storage rack 31 to store the surface longitudinal reinforcing bars; while the bottom surface of the bracket 6 is suspended with a fixed reinforcing bar storage rack 7 to store the bottom longitudinal reinforcing bars. The fixed reinforcing bar storage rack 7 is located exactly above the lower one of the first temporary fixing components 5a, and the two are spatially misaligned. In actual construction, the reinforcing bars extracted from the movable storage rack 31 are directly tied to the uppermost circumferential reinforcing bars fixed by the second component; while the lowermost longitudinal reinforcing bars extracted from the fixed storage rack 7, due to their positional design, can precisely cross over the lower first temporary fixing component 5a, laterally crossing and interlocking, and accurately lapping onto the lower circumferential main reinforcing bars. This three-dimensional staggered layout constructs a natural avoidance passage, completely solving the problem of mutual obstruction between upper and lower level operations.

[0040] Example 2 This embodiment provides a construction method for laying circumferential reinforcement at the bottom of a tunnel, specifically including the following steps: Step 1: Positioning and Hanging Reinforcing Bars First, guide lines are pre-placed on the ground at the tunnel invert construction section. The operator controls the traveling trolley 1 to move longitudinally along the tunnel. During the movement, the operator observes the alignment of the guide lines with the marker plate 102 on the outside of the wheels, ensuring that the plate is always aligned with the guide lines. This action ensures from the outset that the steel mesh to be woven is precisely aligned with the longitudinal axis of the previous work.

[0041] Once in place, the system's built-in synchronous controller controls two sets of four hydraulic cylinders 101 to extend simultaneously, driving the main frame 2 to rise smoothly and raising the work platform to a predetermined construction height, such as chest height, for comfortable operation by workers.

[0042] Subsequently, the pre-cut double-row ring-shaped main steel bars were transported to the site by hand, and the ends of these ring-shaped steel bars were respectively hung into the steel bar clamps 43 at the bottom of the mounting plate 4, in preparation for suspension and traction.

[0043] Step 2: Empty vehicle crosses the span: The drive mechanism starts, and the transverse trolley 3, carrying the unloaded installation plate 4, moves along the arc-shaped track 21 at the bottom of the main frame 2 from one side of the tunnel at the starting point to the other side of the tunnel at the opposite end of the track.

[0044] Step 3: Limiting and locking the first end of the slot: After the traverse trolley 3 reaches the opposite side, the worker synchronously transfers the ends of the double-row ring steel bars and inserts them into the double C-shaped comb spring pieces 41 corresponding to each opening on the mounting plate 4. Due to the large weight of the steel bars themselves, in order to prevent the spring pieces from falling off during subsequent traction, the worker immediately rotates the adjacent limiting mechanism 42 to the locking position, so that the two protrusions 421 on it are firmly embedded like wedges in the gap between the outer wall of the comb spring piece 41 and the inner wall of the opening, thus physically restricting the outward opening deformation of the spring piece.

[0045] Next, the worker places the ends of the reinforcing bars on one side into the limiting grooves 52 of the two sets of temporary fixing components 5 on the opposite side. One set is placed for the upper row of reinforcing bars, and the other set for the lower row. After placement, the worker presses down on the overhead pressure block 53, causing the pressure rod 55 to rotate. At the instant the pressure rod 55 rotates, its coaxial ratchet 551 slides across the surface of the pawl 561 on the long rotating shaft 56, achieving unidirectional single-tooth engagement and locking, thereby independently and instantly and firmly locking the ends of each reinforcing bar into the limiting groove 52. During this process, the first flexible pad 521 and the second flexible pad 531 deform and adhere to the reinforcing bars, providing frictional clamping force.

[0046] Step 4: Tighten the comb and lock the tail end: After one end is fixed, the lateral trolley 3 reverses and returns to the starting point. During the return process, the mounting plate 4 and the combing spring 41 hanging on the rebar act like a rebar comb, pulling and tensioning the double rows of rebars dragging on the ground laterally. Because the rebars are stuck in the two arc-shaped cavities of the double C spring, the horizontal spacing and vertical spacing between the two rows of rebars are forcibly combed and fixed at the same time as the return to the starting point.

[0047] After returning to the starting point, the worker repeats the locking action of S3 above, placing the other end of the double-row ring steel bars into the two sets of temporary fixing components 5 on the starting point side, and pressing down the pressure block 53 to engage the ratchet self-locking mechanism. At this point, the double-layer frame composed of dozens of ring steel bars is taut and suspended in mid-air.

[0048] Step 5: Three-dimensional obstacle avoidance and tying operation: After the double-layer main reinforcement is in place, longitudinal reinforcement needs to be braided. At this time, the transverse trolley 3 drives the mounting plate 4 as a moving ruler, moving longitudinally in fixed lengths, for example, 200mm steps.

[0049] After each movement into position, the worker pauses and extracts the surface longitudinal steel bars from the moving steel bar storage rack 31 on the top surface of the transverse trolley 3, and directly ties them to the upper ring steel bars.

[0050] Meanwhile, another worker pulls out the bottom longitudinal steel bar from the fixed steel bar storage rack 7 suspended at the bottom of the support 6. Due to the spatial misalignment design, this bottom longitudinal steel bar can pass directly across the first temporary fixing component 5a at a lower position without obstruction, and be inserted into and tied to the ring steel bar of the lower layer, so that the upper and lower layer operations do not interfere with each other.

[0051] While tying the longitudinal reinforcement bars, workers simultaneously carried out interlayer welding of the stirrups between the upper and lower layers of the space frame. Throughout the entire process of threading and welding the reinforcement bars, the mounting plate 4 and its spring clips, which tightly hold the double-row main reinforcement bars, always played a role in forcibly fixing the longitudinal and interlayer spacing, ensuring the rigidity and accuracy of the formed space frame.

[0052] Step 6: Overall deployment and one-click instant release: After the double-layer steel reinforcement rigid mesh is woven, the four sets of hydraulic cylinders 101 retract synchronously under the controller command, driving the main frame 2 to descend as a whole, smoothly lowering the steel mesh to the tunnel base surface, and lapping and aligning it with the steel reinforcement reserved in the front section.

[0053] After confirming the landing, the workers activated the reset handles 57 at the ends of the bases 51 on both sides. The rotation of the handles overcame the holding force of the second reset spring 571, causing the entire long rotating shaft 56 to rotate. Instantly, the entire row of pawls 561 simultaneously disengaged from their corresponding ratchet 551 teeth. Without unidirectional restraint, each pressure bar 55 instantly and synchronously rotated under the strong pulling force of its respective first reset spring 552, causing all the pressure blocks 53 to lift upwards in unison. The entire device achieved absolutely synchronous and non-destructive release of the ends of hundreds of steel bars in two rows in less than a second, completely eliminating the deformation of the steel mesh caused by untying each bar individually.

[0054] Step 7: Automatic demolding and exit of rigid mesh: After the ends of the reinforcing bars are released, the entire reinforcing mesh has fallen to the ground. At this point, the sorting mechanism faces the risk of deadlock.

[0055] The worker first rotates the limiting mechanism 42 on the mounting plate 4 in the opposite direction to the release position, so that the two protrusions 421 rotate out of the gap, and the double C-shaped comb spring 41 regains the freedom to open its shape.

[0056] Subsequently, the hydraulic cylinder 101 extends a second time, driving the main frame 2 and the mounting plate upwards. Because the steel mesh is extremely heavy and has become a rigid whole pressed against the ground, under the forceful upward vertical lifting force of the main frame, the lower jaw of the comb-shaped spring piece 41, no longer protected by the limiting protrusion 421, is blocked and squeezed by the steel reinforcement, forcing it to flare outwards, similar to forcibly pulling open an elastic opening ring. The steel reinforcement then slides out from the opened spring piece opening.

[0057] Thus, the sorting mechanism perfectly overcomes the demolding lock problem of rigid mesh, achieving automatic separation from the double-layer steel mesh. Finally, the trolley can move forward along the guide line to enter the next work cycle.

[0058] Although the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Based on the technical solutions of the present invention, various modifications or variations that can be made by those skilled in the art without creative effort are still within the scope of protection of the present invention.

Claims

1. A device for laying circumferential reinforcing bars at the bottom of a tunnel, characterized in that, include: Traveling trolley (1); The main frame (2) is mounted on the traveling trolley (1). A hydraulic cylinder (101) for driving the main frame (2) to lift as a whole is connected between the main frame (2) and the traveling trolley (1). Arc-shaped rails (21) are connected to both ends of the bottom of the main frame (2). A transverse trolley (3) is rotatably connected to the arc-shaped track (21); the bottom of the transverse trolley (3) is detachably connected to an mounting plate (4). The mounting plate (4) has multiple openings arranged in an array. Each opening is equipped with a pair of combing springs (41) with a double C-shaped structure, which are used to simultaneously limit the upper and lower double rows of annular steel bars. The combing springs (41) have elastic flaring deformation capability. The bottom of the mounting plate (4) has two steel bar clamps (43) suspended by two flexible suspension members for each opening. Temporary fixing components (5) are symmetrically distributed at both ends of the arc track (21), and each end is set with two parallel sets to lock the two ends of the upper and lower double-row ring steel bars respectively.

2. The device for laying circumferential reinforcing bars at the bottom of a tunnel according to claim 1, characterized in that: The mounting plate (4) is connected to a limiting mechanism (42) via a damping shaft for each comb spring (41). The limiting mechanism (42) has a locking position and a releasing position. The end of the limiting mechanism (42) away from the rotating shaft is provided with two protrusions (421). When in the locking position, the two protrusions (421) are respectively embedded in the gap between the outer wall of the comb spring (41) and the inner wall of the corresponding opening to restrict the comb spring (41) from expanding outward. When in the releasing position, the limiting mechanism (42) rotates out of the gap to restore the degree of freedom of the comb spring (41) to expand outward.

3. The device for laying circumferential reinforcing bars at the bottom of a tunnel according to claim 2, characterized in that: The temporary fixing component (5) includes a base (51), on which limit grooves (52) are arrayed. The limit grooves (52) are corresponding to the openings on the mounting plate (4). The base (51) has cavities adjacent to each limit groove (52). A pressure rod (55) is hinged inside the cavity, and a pressure block (53) with a corresponding limiting groove (52) is fixedly connected to the pressure rod (55) through a connector (54). A ratchet (551) is coaxially fixed on the hinge shaft of the pressure rod (55). A first return spring (552) is connected between the pressure rod (55) and the side wall of the base (51). The first return spring (552) provides a biasing elastic force to the pressure rod (55) to make it rotate and drive the pressure block (53) to lift upward.

4. The device for laying circumferential reinforcing bars at the bottom of a tunnel according to claim 3, characterized in that: The base (51) has a rotating shaft (56) running through its interior along its length; a pawl (561) is fixedly connected to each ratchet (551) on the rotating shaft (56), and the pawl (561) meshes with the tooth groove of the corresponding ratchet (551) to unidirectionally restrict the lifting of the pressure rod (55).

5. The device for laying circumferential reinforcement at the bottom of a tunnel according to claim 4, characterized in that: The end of the rotating shaft (56) extending out of the base (51) is connected to a reset handle (57), and a second reset spring (571) is connected between the reset handle (57) and the base (51) to provide a rotational holding force to the reset handle (57).

6. The device for laying circumferential reinforcing bars at the bottom of a tunnel according to claim 3, characterized in that: The inner bottom wall of the limiting groove (52) is provided with a first flexible pad (521); the side of the pressure block (53) near the limiting groove (52) is connected to a second flexible pad (531), and the working surface of the second flexible pad (531) is an inwardly concave arc structure.

7. The device for laying circumferential reinforcing bars at the bottom of a tunnel according to claim 1, characterized in that: Each of the two sets of temporary fixing components (5) parallel to each other includes a first temporary fixing component (5a) connected to the end of the arc track (21) and a second temporary fixing component (5b) connected to the main frame (2) by a bracket (6); the bracket (6) is vertically fixed to the side of the main frame (2), and the top horizontal elevation of the first temporary fixing component (5a) is lower than the bottom horizontal elevation of the second temporary fixing component (5b).

8. The device for laying circumferential reinforcing bars at the bottom of a tunnel according to claim 7, characterized in that: The top surface of the transverse trolley (3) is equipped with a follow-up rebar storage rack (31); the bottom surface of the support (6) is equipped with a fixed rebar storage rack (7), which is located above the first temporary fixing component (5a). The two are staggered in spatial layout to form an avoidance channel for the rebar in the fixed rebar storage rack (7) to cross and intersect laterally.

9. The device for laying circumferential reinforcing bars at the bottom of a tunnel according to claim 1, characterized in that: The outer side of the wheels of the traveling trolley (1) is provided with a marking plate (102) for aligning with the construction guide line; two sets of hydraulic cylinders (101) are arranged symmetrically in the longitudinal direction between the traveling trolley (1) and the main frame (2).

10. A construction method for arranging circumferential reinforcement bars at the bottom of a tunnel, characterized in that, Construction using the device for laying circumferential reinforcement at the bottom of a tunnel as described in claim 5 includes the following steps: S1. The traveling trolley (1) is aligned and positioned according to the preset markings. The hydraulic cylinder (101) extends to drive the main frame (2) to rise to the predetermined construction height. The ends of the double-row ring steel bars are placed in the corresponding two steel bar clamps (43). S2, the transverse trolley (3) travels along the arc track (21) to the opposite end of the track; S3. Simultaneously transfer the double-row ring steel bars into a pair of comb-shaped spring pieces (41) of double C-shape, and rotate the limiting mechanism (42) to the locking position to restrict the opening of the spring pieces; S4. Place one end of the double-row ring steel bar into the limiting groove (52) of the two sets of temporary fixing components (5) on the opposite side and press down the pressure block (53) so that the pawl (561) locks the ratchet (551) in one direction, thereby locking the ends of the two steel bars independently in the corresponding limiting groove (52). S5. The transverse trolley (3) returns to the starting point to perform sorting operations on the double-row steel bars. After returning to the starting point, the other end of the double-row ring steel bars is fixed in the two sets of temporary fixing components (5) on the starting point side. S6. The transverse trolley (3) drives the installation plate (4) to move in fixed lengths in stages. Each time it moves to the position, the longitudinal steel bar binding operation is carried out, and the interlayer welding operation of the stirrups is carried out at the same time. During the process, the installation plate (4) provides the positioning and limiting function to fix the spacing of the longitudinal steel bars. S7. The hydraulic cylinder (101) retracts to drive the main frame (2) to descend as a whole, and the steel mesh is lowered to the ground. The reset handles (57) on both sides are turned to make the shaft (56) rotate. The pawl (561) disengages from the ratchet (551). Each pressure bar (55) rotates synchronously under the action of the first reset spring (552) and drives the pressure block (53) to lift upward, so as to release the ends of the double row of steel bars synchronously. S8. Rotate the limiting mechanism (42) to the release position; the hydraulic cylinder (101) extends for the second time to drive the main frame (2) to rise, and the combing spring (41) is forced to open outward under the obstruction of the steel bars, so as to realize the automatic separation of the combing mechanism from the double-layer steel mesh.

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