A self-supporting formwork system applicable to underground structures

Abstract

The present invention discloses a self-supporting formwork system applicable to underground structures, belonging to the technical field of underground structure construction. It includes a top formwork support formwork, both sides of the top formwork support formwork are connected to side formwork support formworks, and a length adjustment device is provided between the top of the side formwork support formwork and the top formwork support formwork to adjust the horizontal distance between the side formwork support formwork and the top formwork support formwork; a top formwork is fixed on the top of the top formwork support formwork, and side formworks are fixed on the sides of the side formwork support formworks. This formwork system increases the internal space of the support. There is no need to install tie rods inside the formwork, and there is no need to add steel bars in the middle of the formwork. The entire formwork is supported by applying prestress, and its length and height can be adjusted, facilitating the use of construction workers.

Description

Technical Field

[0001] The present invention belongs to the technical field of underground structure construction, and particularly relates to a self-supporting formwork system applicable to underground structures. Background Art

[0002] The statements herein only provide background art related to the present invention and do not necessarily constitute prior art.

[0003] In recent years, the construction of urban underground projects, such as underground tunnels, subway sections, utility tunnels, etc., has been vigorously carried out. Taking the utility tunnel as an example, when the utility tunnel is generally constructed by open-cut cast-in-place method, there are problems such as open-air operation, great influence by the natural environment, obvious seasonal construction characteristics, long construction width, and many construction segments. Therefore, during the construction of the utility tunnel, the turnover rate and turnover times of the formwork system have a greater impact on the construction cost of the project.

[0004] The traditional formwork support method for underground structures is to use scattered support and disassembly, with bamboo plywood, wooden squares, and steel pipes scattered and assembled, and the support system uses full hall scaffolds with disc couplers. The adverse effects caused by this are that the on-site construction materials are stacked in a scattered manner, the internal operation space of the scaffold is small, it is difficult for construction workers to walk through and operate, a large amount of labor is required for scaffold disassembly, handling, and installation, and the construction is cumbersome, uses a lot of wood, is not environmentally friendly, laborious, and uneconomical; some use aluminum formwork in combination with full hall scaffolding for construction. The cost of aluminum formwork is high, there is loss, and the operation is not convenient, which is uneconomical. When constructing by the traditional on-site concrete pouring construction method, a lot of anchor rods and scaffolds are required for support. This method requires a large amount of manpower and time, seriously affecting the construction efficiency and construction quality. In addition, for underground structures, the self-waterproof performance of the structure is crucial for the operation and maintenance of the structure. In the prior art, steel rods need to be added in the middle of the formwork to increase the overall stability of the formwork, which has an adverse effect on waterproofing. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a self-supporting formwork system applicable to underground structures. This formwork system increases the internal space of the scaffold. There is no need to install tie rods inside the formwork space, and there is no need to add steel rods in the middle of the formwork. The entire formwork is supported by applying prestress, and its length and height can be adjusted, which is convenient for construction workers to use.

[0006] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0007] In a first aspect, the present invention provides a self - supporting formwork system applicable to underground structures, including a top formwork support formwork. Both sides of the top formwork support formwork are connected to side formwork support formworks, and a length adjustment device is provided between the top of the side formwork support formwork and the top formwork support formwork to adjust the horizontal distance between the side formwork support formwork and the top formwork support formwork; a top formwork is fixed to the top of the top formwork support formwork, and a side formwork is fixed to the side of the side formwork support formwork.

[0008] As a further technical solution, the length adjustment device includes a rotating cylinder. Both ends of the rotating cylinder are connected to telescopic rods. One telescopic rod is connected to the end of the top formwork support formwork, and the other telescopic rod is connected to the top of the side formwork support formwork.

[0009] As a further technical solution, the rotating cylinder is arranged horizontally. Threads in opposite directions are provided at both ends inside the rotating cylinder. The telescopic rods are provided with external threads, and the thread directions of the two telescopic rods are opposite. The rotating cylinder is thread - connected to the telescopic rods. By rotating the rotating cylinder, the two telescopic rods can move away from each other or move towards each other.

[0010] As a further technical solution, the side formwork support formwork includes a vertical rod. A first jack is provided at the bottom of the vertical rod. First anchoring devices are provided at both ends of the vertical rod. A plurality of first struts are fixedly arranged on the side of the vertical rod. A second jack is fixedly arranged at the end of the first strut. A wire - passing port is provided at the top of the second jack. A first steel strand sequentially passes through the wire - passing ports of each second jack, and both ends of the first steel strand are fixed by the two first anchoring devices.

[0011] As a further technical solution, the lengths of the plurality of first struts are not equal or some are equal, and the plurality of first struts are arranged at equal intervals; the first struts are arranged horizontally and are perpendicularly connected to the vertical rod, and a semi - circular structure is arranged inside the wire - passing port.

[0012] As a further technical solution, a connecting rod is provided on the side surface at the bottom of the vertical rod. The connecting rod is arranged horizontally, and the end of the connecting rod is connected to a third jack. A channel - shaped connecting piece is fixedly arranged at the top of the third jack and is connected to the bottom of an inclined strut. The top of the inclined strut is connected to the wire - passing port of one of the first struts; a fourth jack is provided at the bottom of the channel - shaped connecting piece, and universal wheels are fixedly arranged at the bottom of the vertical rod and the bottom of the channel - shaped connecting piece.

[0013] As a further technical solution, the top formwork support formwork includes a cross - bar. Second anchoring devices are provided at both ends of the cross - bar. A plurality of second struts are fixedly arranged at the bottom of the cross - bar. A fifth jack is fixedly arranged at the end of the second strut. A wire - passing port is provided at the top of the fifth jack. A second steel strand sequentially passes through the wire - passing ports of each fifth jack, and both ends of the second steel strand are fixed by the two second anchoring devices.

[0014] As a further technical solution, the lengths of multiple second struts are unequal or partially equal, and the multiple second struts are arranged at equal intervals; the second struts are arranged vertically and are perpendicularly connected to the cross bar, and a semi-circular structure is arranged inside the wire passing opening.

[0015] As a further technical solution, a groove is arranged on one side of the top formwork and the side formwork, and a rubber pad is arranged on the other side; a connection port is arranged on one side of the top formwork and the side formwork, and a connection plug is arranged on the other side.

[0016] As a further technical solution, top ribs are arranged on the plate surface of the top formwork, side ribs are arranged on the plate surface of the side formwork, the side formwork support formwork is fixedly connected to the side ribs, and the top formwork support formwork is fixedly connected to the top ribs.

[0017] The beneficial effects of the present invention are as follows:

[0018] In the self-supporting formwork system of the present invention, the top formwork is fixed by the top formwork support formwork, the side formwork is fixed by the side formwork support formwork, and a length adjustment device is connected between the top formwork support formwork and the side formwork support formwork to adjust the horizontal distance between the side formwork support formwork and the top formwork support formwork, thereby facilitating the separation of the side formwork from the side wall; and a first jack is installed at the bottom of the side formwork support formwork, which can effectively perform the telescopic lifting of the formwork, so as to complete the demoulding from the top concrete and the side wall concrete.

[0019] In the self-supporting formwork system of the present invention, through the connection between the side formwork support formwork, the top formwork support formwork, and the top formwork and the side formwork, the integrity of the formwork is good, the structure is simple and reasonable, and the construction is safe and reliable. The member structure and connection method of the formwork are standardized, reducing the randomness of lapping; and the internal space of the formwork system is large, the operation is simple, the efficiency is high, avoiding the traditional formwork of the full hall support with disc buckles, there is no need to install tie rods inside the formwork, which is convenient for construction personnel to walk inside, and there is no need to add steel rods in the middle of the formwork to increase the overall stability of the formwork, and the waterproof performance is better.

[0020] In the self-supporting formwork system of the present invention, a second jack is arranged at the end of the first strut of the side formwork support formwork, and a fifth jack is arranged at the end of the second strut of the top formwork support formwork. When it is monitored that the local inward deformation or the deformation development rate of the support formwork is different from the expected value or exceeds the alarm value, the size of the steel strand tension and its distribution on each strut can be changed by changing the jacks on each strut, and the internal deformation of the formwork can be reduced by making the size and distribution of the steel strand tension as equal as possible. The way of applying the supporting force of this formwork system is different from that of the traditional formwork. This formwork applies pressure to the jack, thereby applying a force to the steel strand to generate a tensile force on the steel strand to support the formwork.

[0021] In the self-supporting formwork system of the present invention, the internal through-wire openings at the top ends of the second jacks at the first struts and the fifth jacks at the second struts adopt a semi-circular structure, so that there will be no angular friction between the steel strands and the retaining plates during the application of the prestressed steel strands, effectively reducing the friction loss of the steel strands during the prestress tensioning stage. The small friction loss of the prestress of the steel strands can make the actual stress condition and deformation control condition of the structure more consistent with the design results, further ensuring the safety of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The attached drawings forming a part of this specification are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0023] Figure 1 is a perspective view of the self-supporting formwork system of the present invention;

[0024] Figure 2 is a front view of the self-supporting formwork system of the present invention;

[0025] Figure 3 is a schematic diagram of the side formwork support formwork of the present invention;

[0026] Figure 4 is a schematic diagram of the setting of the through-wire opening at the top end of the second jack of the present invention;

[0027] Figure 5 is a schematic diagram of the setting of the through-wire opening at the top end of the second jack connected to the diagonal strut of the present invention;

[0028] Figure 6 is a schematic diagram of the first anchoring device of the present invention;

[0029] Figure 7 is a schematic diagram of the setting of the grooved connecting piece of the third jack at the connecting rod of the present invention;

[0030] Figure 8 is a schematic diagram of the setting of the universal wheels of the side formwork support formwork of the present invention;

[0031] Figure 9 is a schematic diagram of the top formwork support formwork of the present invention;

[0032] Figure 10 is a schematic diagram of the length adjusting device of the present invention;

[0033] Figure 11 is a schematic diagram of the side formwork of the present invention;

[0034] Figure 12 is a schematic diagram of the top formwork of the present invention;

[0035] Figure 13 is a schematic diagram of the connecting plugs set for the side formwork and the top formwork of the present invention;

[0036] Figure 14 It is a schematic diagram of the connection ports provided on the side formwork and top formwork of the present invention;

[0037] In the figure: The distances or dimensions between each part are exaggerated for showing the positions of each part, and the schematic diagram is only for illustration purposes;

[0038] Among them, 1 is the top formwork support scaffold, 11 is the cross bar, 12 is the second strut, 13 is the fifth jack, 14 is the wire passing port, 15 is the second steel strand, 16 is the second anchoring device, 2 is the side formwork support scaffold, 21 is the vertical bar, 211 is the connecting rod, 212 is the grooved connecting piece, 213 is the bottom positioning hole, 22 is the first strut, 23 is the first anchoring device, 231 is the working wedge, 232 is the anchor plate, 233 is the anchor backing plate, 24 is the first steel strand, 251 is the first jack, 252 is the second jack, 253 is the third jack, 254 is the fourth jack, 26 is the wire passing port, 27 is the diagonal strut, 28 is the universal wheel, 29 is the positioning hole, 3 is the top formwork, 31 is the top edge, 4 is the side formwork, 41 is the side edge, 5 is the length adjusting device, 51 is the rotating cylinder, 52 is the telescopic rod, 53 is the positioning plate, 54 is the fixing block, 6 is the groove, 7 is the rubber pad, 8 is the connection port, 9 is the connection plug. Detailed implementation manners

[0039] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further explanations of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0040] In a typical implementation manner of the present invention, as Figure 1 shown, a self - supporting formwork system applicable to underground structures is proposed, which mainly includes a top formwork support scaffold 1, a side formwork support scaffold 2, a top formwork 3 fixed on the top formwork support scaffold 1, and a side formwork 4 fixed on the side formwork support scaffold 2; the top formwork support scaffold 1 is located at the top, two side formwork support scaffolds 2 are provided, the two side formwork support scaffolds 2 are opposite and spaced apart, the two side formwork support scaffolds 2 are respectively connected to both sides of the top formwork support scaffold 1, and a length adjusting device 5 is provided between the top of the side formwork support scaffold 2 and the top formwork support scaffold 1, and the horizontal distance between the side formwork support scaffold 2 and the top formwork support scaffold 1 can be adjusted through the length adjusting device 5.

[0041] Among them, the side formwork support scaffold 2 mainly includes vertical rods 21, first struts 22, first anchoring devices 23, first steel strands 24, first jacks 251, second jacks 252, third jacks 253, fourth jacks 254, wire passing openings 26, diagonal struts 27, and universal wheels 28. Among them, the vertical rods 21 are arranged vertically, and the first anchoring devices 23 are welded to the vertical rods 21 to form a whole; the first anchoring devices 23 are fixedly arranged at both the upper and lower ends of the vertical rods 21. Multiple first struts 22 are arranged on the side of the vertical rods 21. The lengths of the multiple first struts 22 are not equal or partially equal, and the multiple first struts 22 are arranged at equal intervals and are connected to the vertical rods 21 by bolts; the first struts 22 are arranged horizontally and are perpendicularly connected to the vertical rods 21. The end of the first strut 22 is connected to the second jack 252 by a bolt, and its function is to apply a force to the steel strand to generate a tensile force on the steel strand; after the first anchoring device 23 applies prestress to the steel strand, during the construction stage, when the prestress is insufficient, the prestress can be increased by adjusting the second jack 252.

[0042] A wire passing opening 26 is arranged at the end of the second jack 252 connected to the first strut 22. The inside of the wire passing opening 26 adopts a semi-circular structure, which can prevent the steel strand from being worn and extend the service life of the steel strand. The first steel strand 24 passes through the wire passing openings at the ends of each second jack 252 in sequence, and both ends of the first steel strand 24 are fixed by the first anchoring devices 23 at the upper and lower ends of the vertical rod 21. The bottom of the second jack 252 is connected to the first strut 22 by a fixing plate. A positioning hole 29 is arranged on the fixing plate, and the second jack 252 and the first strut 22 are connected by passing a bolt through the positioning hole 29.

[0043] In this embodiment, the first steel strand 24 forms an arc shape, and the first struts 22 are arranged on the vertical rod 21 as follows: the length of the first strut 22 gradually decreases from the middle of the vertical rod 21 to both ends to support the first steel strand 24.

[0044] The first anchoring device 23 mainly includes working wedges 231, an anchor plate 232, and an anchor backing plate 233. The anchor backing plate 233 is fixed to the side of the vertical rod 21. The anchor backing plate 233 is in a U shape. An anchor plate 232 is arranged inside the anchor backing plate 233. The anchor plate 232 is provided with a through hole for the first steel strand 24 to pass through, and working wedges 231 are arranged at the through hole of the anchor plate 232 to fix the first steel strand 24.

[0045] A connecting rod 211 is provided on the side surface of the bottom of the vertical rod 21. The connecting rod 211 is arranged horizontally and is fixedly connected to the third jack 253 by bolts. A grooved connecting piece 212 is fixedly connected to the end of the third jack 253. A bottom positioning hole 213 is provided at the grooved connecting piece 212 to position the position of the diagonal strut 27. The bottom of the diagonal strut 27 is fixedly connected to the grooved connecting piece 212 of the connecting rod 211, and the top of the diagonal strut 27 is connected to the wire passing port 26 at the end of a certain first strut 22. A U-shaped connecting piece is provided at the wire passing port 26 to fixedly connect the diagonal strut 27 to the U-shaped connecting piece.

[0046] A first jack 251 is installed at the bottom end of the vertical rod 21, and a fourth jack 254 is installed at the bottom end of the grooved connecting piece 212. The functions of the first jack 251 and the fourth jack 254 are to lift and lower the side formwork support scaffold 2 to facilitate the separation of the scaffold from the top concrete. Universal wheels 28 are installed on the side surface of the grooved connecting piece 212 and the side surface of the vertical rod 21 to facilitate the movement and transfer of the scaffold.

[0047] Among them, the top formwork support scaffold 1 mainly includes a cross bar 11, a second strut 12, a fifth jack 13, a wire passing port 14, a second steel strand 15, a second anchoring device 16, etc. The cross bar 11 is arranged horizontally, and a plurality of second struts 12 are arranged at equal intervals at the bottom of the cross bar 11. The second struts 12 are connected to the cross bar 11 by bolts, and the second struts 12 are arranged vertically. The lengths of the plurality of second struts 12 are not equal or some are equal. Each bottom of the second strut 12 is fixedly connected to a fifth jack 13 by bolts, and a wire passing port 14 is provided at the end of the fifth jack 13. Second anchoring devices 16 are provided at both ends of the cross bar 11. The second steel strand 15 passes through the wire passing ports 14 at the ends of the respective fifth jacks 13 in sequence, and both ends of the second steel strand 15 are fixed to the second anchoring devices 16 at both ends of the cross bar 11.

[0048] It should be noted that the wire passing port 14, the second steel strand 15, and the second anchoring device 16 of the top formwork support scaffold 1 are the same as the wire passing port 26, the first steel strand 24, and the first anchoring device 23 in the side formwork support scaffold 2, and will not be elaborated here.

[0049] A length adjustment device 5 is arranged at each end of the crossbar 11 of the top formwork support formwork 1. The length adjustment devices 5 at both ends of the top formwork support formwork 1 are aligned with the top of the side formwork support formwork 2 and are fixedly connected with bolts, thereby fixing the top plate support formwork 1 and the side formwork support formwork 2 into a whole. The length adjustment device 5 is connected to the vertical bar 21 of the side formwork support formwork 2, and is mainly responsible for the contraction and stretching of the side formwork support formwork 2; the length adjustment device 5 includes a rotating drum 51, and both ends of the rotating drum 51 are connected to telescopic rods 52, one end of the telescopic rod 52 is provided with a positioning plate 53 connected to the end of the crossbar 11, and the other end of the telescopic rod 52 is provided with a fixing block 54 connected to the end of the vertical rod 21, and the fixing block 54 can be provided with a groove and fixedly connected to the top of the vertical rod 21.

[0050] The rotating drum 51 is arranged horizontally, and threads in opposite directions are arranged at both ends of the rotating drum 51. The telescopic rod 52 is provided with external threads, and the threads of the two telescopic rods 52 are in opposite directions. The rotating drum 51 and the telescopic rod 52 are threadedly connected. By rotating the rotating drum 51, the two telescopic rods 52 can be moved away from each other or towards each other, and then extended or contracted, driving the side template support formwork 2 to approach or leave the side wall.

[0051] A groove 6 is provided on one side of the top template 3 and the side template 4, and a rubber pad 7 is provided on the other side. When the adjacent top templates or adjacent side templates are assembled, the grooves and rubber pads are assembled and spliced, which is convenient for assembly and the rubber pads can effectively prevent water. A connection port 8 is provided on one side of the top template 3 and the side template 4, and a connection plug 9 is provided on the other side. Through the connection of the adjacent template connection plug and the connection port, the two templates are effectively locked during assembly.

[0052] The top template 3 is provided with a top rib 31, the side template 4 is provided with a side rib 41, the vertical rod 21 of the side template support formwork 2 is fixedly connected to the side rib 41 of the side template 4, and the cross rod 11 of the top template support formwork 1 is fixedly connected to the top rib 31 of the top template 3.

[0053] When connecting adjacent side formworks 4 or adjacent top formworks 3, the connection plug 9 is inserted into the connection port 8, aligned with the vertical locking port at the connection port 8, and the bolt is inserted into the locking port for locking.

[0054] The formwork system has modular construction, unit overall construction turnover, and neat formwork support, which is conducive to civilized construction and site management. The self-supporting formwork system can be prefabricated in the factory and assembled on site, and can be recycled and reused, meeting the requirements of energy conservation and emission reduction. It is an economical, efficient, green and environmentally friendly support system.

[0055] In order to make the technical means, innovative features, objectives and effects achieved by the present invention easy to understand, the method of using the present invention is further explained below using an underground comprehensive pipe gallery as an example.

[0056] First step, foundation treatment: Prepare the concrete cushion, complete the installation and binding of the bottom steel bars of the underground structure, pour the concrete. After the bottom concrete curing is completed and its concrete strength meets the standard, the subsequent operations can be carried out.

[0057] Second step, assemble the side formwork support formwork 2; Place the vertical rod 21 flat on the ground, and evenly distribute multiple first struts 22 on the vertical rod 21. The lengths of the first struts 22 are unequal or partially equal. The first struts 22 are arranged at equal intervals, with a spacing of 0.5 - 1 meter and a quantity of 3 - 5 pieces, and are connected to the vertical rod 21 through bolts. The end of the first strut 22 is fixedly connected to the second jack 252 through bolts, and the end of the second jack 252 is fixedly connected to the wire passing port 26. The anchor plate 233 in the first anchoring device 23 is welded to the vertical rod 21. Fix one end of the first steel strand 24 to the first anchoring device 23 near the top of the vertical rod 21. The fixing method is that the first steel strand 24 passes through the anchor plate 233 and the anchor plate 232, install the working wedge-shaped clamp 231 on the first steel strand 24, and tighten the first steel strand 24 to lock it on the anchor plate 232. Pass the first steel strand 24 through the wire passing ports 26 of each second jack 252 from top to bottom in sequence. The other end of the first steel strand 24 is fixed to the first anchoring device 23 at the bottom of the vertical rod 21, and the entire first steel strand 24 is tightened on the formwork. Install a connecting rod 211 at the bottom of the vertical rod 21, install a third jack 253 at its end, and a channel-shaped connecting piece 212 is fixed at the end of the third jack 253. Connect one end of the diagonal strut 27 to the wire passing port 26 of one of the second jacks 252, and the other end is fixed to the channel-shaped connecting piece 212. When the second jack 252 at the wire passing port 26 extends, to ensure that the diagonal strut 27 is in a diagonal bracing state, the third jack 253 at the channel-shaped connecting piece 212 can be adjusted to keep the diagonal strut 27 in a diagonal bracing state all the time. The first jack 251 at the bottom of the vertical rod 21 and the fourth jack 254 at the bottom of the channel-shaped connecting piece 212 are mainly responsible for the lifting and lowering of the formwork, facilitating the demoulding of the top concrete, and the lifting height is 10 - 20 centimeters. Install universal wheels 28 on the side of the vertical rod 21 and the side of the channel-shaped connecting piece 212, which can rotate 360 degrees, facilitating the transfer of the formwork.

[0058] The third step is the assembly of the top formwork support scaffold 1. A number of second struts 12 are evenly arranged on the cross bar 11, with the number being 3 - 5, the spacing being 0.5 - 1 meter, and their lengths being unequal or partially equal. A fifth jack 13 is installed at the end of the second strut 12, and the end of the fifth jack 13 is fixedly connected to the wire passing port 14. The fixing method of the second steel strand 15 is the same as that of the first steel strand 24 of the side formwork support scaffold 2. One end of the second steel strand 15 is fixed to the second anchoring device 16 on one side of the cross bar 11, and the second steel strand 15 is allowed to pass through the wire passing port 14 in sequence and is fixed to the second anchoring device 16 on the other side. The second steel strand 15 is tightened on the scaffold and locked at the second anchoring devices 16 at both ends. Length adjusting devices 5 are respectively installed at both ends of the cross bar 11, with the elongation length being 5 - 15 cm. Its function is to be responsible for the contraction and elongation of the side formwork support scaffold 2, facilitating the demoulding from the side wall concrete.

[0059] The fourth step is the assembly of the overall scaffold. Use lifting equipment to erect the two side formwork support scaffolds 2, and fixedly connect them to the side formwork 4 through bolts. Install the frontmost and rearmost parts of the formwork respectively to keep the entire side formwork support scaffold 2 upright. The remaining side formwork support scaffolds 2 are arranged at equal intervals inside the two scaffolds and installed, with the spacing being 1 - 1.5 meters. After the left and right side formwork support scaffolds 2 and the side formwork 4 are installed, use lifting equipment to lift the top formwork support scaffold 1 and place it on the top of the left and right side formwork support scaffolds 2. The length adjusting devices 5 at both ends of the top formwork support scaffold 1 are fixedly connected to the top of the side formwork support scaffold 2 through bolts. Install the top formwork 3 on the top formwork support scaffold 1 to form an integral structure. The overall height of this self - supporting scaffold system is 3 - 6 meters, and the span is 3 - 6 meters.

[0060] The fifth step is to move this scaffold into the interior of the steel bar skeleton of the underground utility tunnel, with its direction being consistent with the length direction of the utility tunnel. During the movement of the scaffold, the length adjusting device 5 and the first jack 251 and the fourth jack 254 at the bottom of the scaffold are in a contracted state, and the installed first steel strand 24 and the first anchoring device 23 are fixed and in a tightened state. The second steel strand 15 and the second anchoring device 16 are fixed and in a tightened state. When the scaffold moves to the designated position, adjust the first jack 251 and the fourth jack 254 at the bottom end of the side formwork support scaffold 2 to raise it to the designated height of the utility tunnel. Adjust the length adjusting devices 5 at both ends of the top formwork support scaffold 1, rotate the rotating cylinder 51 on this device to extend the telescopic rod 52 to reach the designated width of the tunnel.

[0061] Step 6: Apply prestress to the formwork. At this time, the first steel strand 24 of the side formwork support formwork 2 and the second steel strand 15 of the top formwork support formwork 1 are in a taut state. Both ends of the first steel strand 24 are locked by the first anchoring device 23, and both ends of the second steel strand 15 are locked by the second anchoring device 16. By adjusting the second jack 252 at the end of the first strut 22 and the fifth jack 13 at the end of the second strut 12, pressurize the first steel strand 24 and the second steel strand 15, apply a force to the first steel strand 24 and the second steel strand 15, so that the first steel strand 24 and the second steel strand 15 generate tensile forces to support the entire self-supporting system. When pressurizing the second jack 252 at the connection of the diagonal strut 27, it is necessary to adjust the third jack 253 at the grooved connector 212 to ensure that the diagonal strut 27 is in a diagonal bracing state.

[0062] Step 7: Pour the concrete on the side and top of the utility tunnel. During the concrete pouring process, attention should be paid to vibrating the concrete. If the prestress of the self-supporting formwork is insufficient during pouring or curing, the second jack 252 at the end of the first strut 22 of the side formwork support formwork 2 and the fifth jack 13 at the end of the second strut 12 of the top formwork support formwork 1 can be adjusted to continue pressurizing to increase the prestress.

[0063] Step 8: After the poured body meets the standards, demold the formwork. First, release all the prestresses on the first steel strand 24 and the second steel strand 15, and release the pressure on each jack on the side formwork support formwork 2 and the top formwork support formwork 1 in sequence, so that the first steel strand 24 and the second steel strand 15 return to the initial state. Secondly, adjust the first jack 251 and the fourth jack 254 at the bottom of the side formwork support formwork 2 to lower their heights, separate from the top concrete, and lower until the universal wheels 28 at the bottom of the formwork touch the ground. Then, reverse-rotate the length adjustment device 5 on the top formwork support formwork 1, the telescopic rod 52 retracts, driving the side formwork support formwork 2 to move so that the left and right side formworks 4 are separated from the side wall.

[0064] Step 9: Move the formwork to the next working position and repeat Steps 5 to 8 above.

[0065] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A self - supporting formwork system applicable to underground structures, characterized in that, It includes a top formwork support scaffold, both sides of the top formwork support scaffold are connected to the side formwork support scaffolds, and a length adjustment device is provided between the top of the side formwork support scaffold and the top formwork support scaffold to adjust the horizontal distance between the side formwork support scaffold and the top formwork support scaffold; The top formwork is fixed on the top of the top formwork support scaffold, and the side formwork is fixed on the side of the side formwork support scaffold; The side formwork support scaffold includes vertical rods, a first jack is provided at the bottom of the vertical rods, first anchoring devices are provided at both ends of the vertical rods, a plurality of first struts are fixedly arranged on the side of the vertical rods, a second jack is fixedly arranged at the end of the first struts, a wire passing port is provided at the end of the second jack, a first steel strand sequentially passes through the wire passing ports of each second jack, and both ends of the first steel strand are fixed by the two first anchoring devices; A connecting rod is provided on the side surface of the bottom of the vertical rod, the connecting rod is arranged horizontally, the end of the connecting rod is connected to a third jack, a grooved connecting piece is fixedly arranged at the end of the third jack and is connected to the bottom of the inclined strut, and the top of the inclined strut is connected to the wire passing port of one of the first struts; a fourth jack is provided at the bottom of the grooved connecting piece, and universal wheels are fixedly arranged at the bottom of the vertical rod and the bottom of the grooved connecting piece.

2. The self-supporting formwork system applicable to underground structures according to claim 1, characterized in that, The length adjustment device includes a rotating cylinder, both ends of the rotating cylinder are connected to telescopic rods, one telescopic rod is connected to the end of the top formwork support scaffold, and the other telescopic rod is connected to the top of the side formwork support scaffold.

3. The self-supporting formwork system applicable to underground structures according to claim 2, wherein The rotating cylinder is arranged horizontally, opposite threads are provided at both ends inside the rotating cylinder, external threads are provided on the telescopic rods, and the thread directions of the two telescopic rods are opposite. The rotating cylinder is threadedly connected to the telescopic rods, and by rotating the rotating cylinder, the two telescopic rods can move away from each other or move towards each other.

4. The self-supporting formwork system applicable to underground structures according to claim 1, characterized in that, The lengths of a plurality of first struts are not equal or partially equal, and the plurality of first struts are arranged at equal intervals; the first struts are arranged horizontally and are perpendicularly connected to the vertical rods, and a semi-circular structure is arranged inside the wire passing port.

5. The self-supporting formwork system applicable to underground structures according to claim 1, characterized in that, The top formwork support scaffold includes cross bars, second anchoring devices are provided at both ends of the cross bars, a plurality of second struts are fixedly arranged at the bottom of the cross bars, a fifth jack is fixedly arranged at the end of the second struts, a wire passing port is provided at the end of the fifth jack, a second steel strand sequentially passes through the wire passing ports of each fifth jack, and both ends of the second steel strand are fixed by the two second anchoring devices.

6. The self-supporting formwork system applicable to underground structures as described in claim 5, characterized in that, The lengths of a plurality of second struts are not equal or partially equal, and the plurality of second struts are arranged at equal intervals; the second struts are arranged vertically and are perpendicularly connected to the cross bars, and a semi-circular structure is arranged inside the wire passing port.

7. The self-supporting formwork system applicable to underground structures as described in claim 1, characterized in that, A groove is provided on one side of the top formwork and the side formwork, and a rubber pad is provided on the other side; a connection port is provided on one side of the top formwork and the side formwork, and a connection plug is provided on the other side.

8. The self-supporting formwork system applicable to underground structures according to claim 1, characterized in that, Top ribs are arranged on the surface of the top formwork, side ribs are arranged on the surface of the side formwork, the side formwork support scaffold is fixedly connected to the side ribs, and the top formwork support scaffold is fixedly connected to the top ribs.

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