Dismantling method for cast-in-place concrete arch suspended splicing steel arch support system

Abstract

The invention discloses a cast-in-place concrete arch suspended splicing steel arch support system dismantling method, which relates to the technical field of bridge construction, and comprises the following steps of: sequentially arranging a plurality of safety steel wire ropes at intervals along the length direction of a suspended splicing steel arch; a hanging steel wire rope is arranged at the arch frame unit to be dismantled; a winch system is installed on the concrete arch, a winch steel wire rope of the winch system is connected with the arch frame segment to be dismantled from the side face, and a chain block and a tower crane steel wire rope are connected; through mutual cooperation of a winch system and a chain block, the arch frame segment to be dismantled is pulled to the edge of a concrete arch; and hoisting out and storing the arch frame section to be dismantled through a tower crane steel wire rope. And the steps are repeated, and all the arch frame units are dismantled column by column till the whole suspended splicing steel arch frame is completely dismantled. The construction method is low in construction site requirement, simple in structure and convenient and fast to construct, extra large hoisting equipment for assistance is not needed, and the integrity of the concrete arch structure after construction is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of bridge construction technology, in particular to a cast-in-situ concrete arch suspension splicing steel arch support system dismantling method. BACKGROUND

[0002] The concrete arch structure can fully utilize the compressive strength of concrete, save more materials under the same span condition compared with the simply supported beam and continuous rigid frame beam structure, and can effectively cross the topography such as mountainous areas, gorges and rivers, and is widely used in the field of bridge and water conservancy aqueduct construction. When the concrete arch structure is constructed, the suspension splicing steel arch is often used as a support structure, and the suspension splicing steel arch is dismantled after the construction of the concrete arch structure is completed.

[0003] The steel arch is often spliced by multiple pieces of Bailey beam in segments, each segment is connected by a pin shaft and a flat link scissors support, and when installed, it can be hoisted by means of inclined cable fastening, cable hoist, etc., the inclined cable fastening system is dismantled after closure, and the concrete formwork support system is formed by laying distribution batten and bottom die on the top of the Bailey beam.

[0004] When the steel arch is dismantled, due to the obstruction of the completed arch structure, the construction space of the arch structure bottom plate is limited, and the hoisting equipment cannot enter the arch below for operation, and the steel arch dismantling is faced with the problem of hoisting and lowering after disassembly. At the same time, the area using arch structure is basically the terrain of crossing river or valley, and the dismantling site is limited, so it is difficult to arrange large mechanical equipment, and the dismantling is difficult.

[0005] As in the existing literature, a steel arch dismantling device for construction of a deck type box arch bridge, with publication number CN210684485U, in which multiple hoisting rods are pre-buried in the arch bridge concrete to connect with the steel arch, and multiple hoisting rope holes are reserved on the bridge; the steel arch is dismantled in segments, and a winch is set on the bridge to connect with the segment through the hoisting rope when each segment is dismantled, then the connection between the segment and the hoisting rod and other segments is released, and the segment is lowered to the lower transport ship by the winch. The steel arch dismantled by the device can only be vertically lowered, and is only suitable for the case where the terrain under the arch bridge is flat and the traffic is convenient, or the river has the condition of setting a floating ship or a floating box. For the case of mountainous and deep valley areas where the lower part of the arch bridge cannot be passed and there is no stacking condition, the device cannot be applied. At the same time, a large number of hoisting rods reserved in the arch bridge concrete need to be cut off later, and the concrete needs to be repaired, which increases the workload and construction difficulty.

[0006] A construction method for the overall installation and dismantling of the arch frame of a cast-in-place arch bridge, disclosed in CN119162925A, involves dismantling the arch frame by detaching the lateral connections of individual arch frames in groups, installing tie rods, and moving each group laterally to the outside of the arch rib. The method then uses cable cranes to lift each group to the bridge deck for dismantling. This method requires sufficient space on site for pushing and moving the arch frames, making it difficult to implement under limited space conditions. Furthermore, each group of arch frames is lifted as a whole during dismantling. For large-span heavy arch frames, the weight of each group is often large, requiring the use of large lifting equipment. The tower cranes and cable cranes commonly used on site are insufficient to meet the lifting requirements.

[0007] A method for dismantling a steel arch frame used in the construction of a box-type reinforced concrete arch bridge, disclosed in CN118814615A, comprises the following steps: dividing the steel arch frame into one arch crown segment, two arch waist segments, and two arch foot segments; setting up two winches on both sides of the arch crown segment on the bridge, and setting up a tie tower on each bank; inserting two transverse beams through both ends of the arch crown segment in the transverse direction of the bridge, and inserting one transverse beam through each arch waist segment and arch foot segment; firmly connecting the transverse beams in the arch crown segment to the winches on both sides of the bridge, and firmly connecting the transverse beams in the arch waist segment and arch foot segment to the tie towers on both banks using steel strands; first, lowering the arch crown segment onto the transport ship using the winches, then vertically rotating the arch waist segment and arch foot segment downwards as a whole, supporting the left arch waist segment on the transport ship, dismantling the arch waist segment, and finally vertically rotating the arch foot segment onto the transport ship and dismantling the arch foot segment. This method is only applicable in situations where the terrain beneath the arch bridge is flat and easily accessible, or in waterways suitable for setting up floating boats or pontoons. It cannot be applied in mountainous areas with deep valleys and canyons where the area beneath the arch bridge is impassable and there are no suitable storage facilities. Furthermore, during on-site construction, to improve efficiency and save costs, the anchor towers are usually installed on the top of the nearest pier and are immediately removed after the steel arch frame is installed to avoid affecting the construction of the bridge deck structure above the piers. Therefore, in actual construction, the anchor towers are often already removed, and subsequent restoration will further increase costs. Retaining the anchor towers could potentially impact bridge deck construction.

[0008] A method for dismantling a cast-in-place arch frame of a concrete arch bridge, disclosed in publication number CN117344660A, comprises the following steps: First, a temporary arch seat is set up. Then, the position of the tie cable and spreader beam is adjusted to be away from the arch rib by lateral jacking. Next, the segment to be dismantled is jacked laterally to move to the outside of the arch rib. Finally, a tower crane is used for dismantling. This process of jacking and dismantling is repeated until the entire structure is dismantled. This method provides sufficient space on the side of the arch seat for arranging a temporary arch seat to facilitate lateral movement of the arch frame, while retaining the tie cable for the tower base. Summary of the Invention

[0009] This invention addresses the limitations of existing methods for dismantling suspended steel arch supports, which are unsuitable for situations with limited demolition sites or road transportation conditions, or where it is impossible to retain the anchor towers and cables due to construction needs. The aim is to provide a method for dismantling a suspended steel arch support system for cast-in-place concrete arches. This method has minimal requirements for construction sites, a simple structure, and is convenient and quick to construct. It does not require additional large-scale hoisting equipment and improves the integrity of the concrete arch structure after construction.

[0010] This invention is achieved through the following technical solution:

[0011] A method for dismantling a cast-in-place concrete arch cantilever steel arch support system includes the following steps:

[0012] S1: Several safety steel wire ropes are arranged at intervals along the length of the suspended steel arch frame. A safety steel wire rope is provided at each arch frame unit, and the safety steel wire rope is used to connect the arch frame unit and the concrete arch.

[0013] S2: Install a hoisting steel wire rope at the arch frame unit to be demolished, and connect the hoisting steel wire rope around the concrete arch above;

[0014] S3: In the arch frame unit to be dismantled, disconnect the first arch frame segment to be dismantled at the column end from the safety wire rope, while keeping the safety wire rope connected to the undismantled arch frame in the column direction;

[0015] S4: Install a winch system on the concrete arch, connect the winch wire rope of the winch system to the arch segment to be demolished from the side, so that the winch wire rope can apply a horizontal lateral force to the arch segment to be demolished; install hand chain hoists at both ends of the arch segment to be demolished, and connect the hand chain hoists to the arch segment to be demolished and the hoisting wire rope respectively; at the same time, connect the tower crane wire rope to the lifting point of the arch segment to be demolished.

[0016] S5: Disconnect the arch frame segment to be demolished from the existing arch frame, and pull the arch frame segment to be demolished to the edge of the concrete arch by means of the cooperation of the winch system and the hand chain hoist.

[0017] S6: Then, the arch frame segment to be dismantled can be lifted out and stored using the tower crane's wire rope;

[0018] S7: Repeat steps S3-S6 until all the arch frame units to be demolished have been removed;

[0019] S8: Repeat steps S2-S7 to dismantle each arch frame unit column by column until the entire cantilevered steel arch frame is completely dismantled.

[0020] In a further optimization, in step S1, when connecting the safety wire rope, the safety wire rope needs to be passed through the upper chord of the suspended steel arch frame along the column direction, and the two ends that have passed through are pulled up and tightened around the concrete arch to bind the concrete arch and the suspended steel arch frame together to form a safety system.

[0021] In a further optimization, during the connection process of the safety wire rope and the hoisting wire rope, a semi-circular pipe protection device is set at the four corners where both come into contact with the concrete arch. The semi-circular pipe protection device includes a semi-circular steel pipe, and both pass through or contact the semi-circular steel pipe.

[0022] The two ends of the semi-circular steel pipe are respectively connected to the two adjacent sides of the concrete arch.

[0023] In a further optimization, in step S2, after installing the hoisting wire rope, a hand-operated hoist needs to be hung between the hoisting wire rope and the arch frame unit to be dismantled as a fall protection device.

[0024] In a further optimization, the winch system includes a winch and a base. The winch is fixed to the concrete arch surface by the base, and the base is anchored into the concrete arch by several anchor bars.

[0025] For further optimization, the diameter of the anchor bar is not less than 20mm.

[0026] In a further optimization, the winch system also includes a reversing pulley. Reversing pulleys are installed at the upper and lower ends of the side of the concrete arch. The winch wire rope is connected to the arch frame segment to be dismantled in sequence through the upper and lower reversing pulleys.

[0027] In a further optimization, in step S4, after installing hand-operated hoists at both ends of the arch frame segment to be dismantled, it is also necessary to install hand-operated hoists on the undismantled arch frame behind the arch frame segment to connect the undismantled arch frame with the hoisting wire rope.

[0028] Further optimization, step S5 includes the following specific steps:

[0029] S51: Remove the corresponding pins and horizontal scissor braces between the arch frame segment to be demolished and the arch frame not yet demolished to disconnect the connection between the arch frame segment to be demolished and the arch frame not yet demolished; then slowly adjust the arch frame segment to be demolished by using the hand-operated hoists at both ends, and adjust it to be horizontal in the air.

[0030] S52: Then start the winch system to apply a horizontal lateral force to the arch frame segment to be demolished, so that the arch frame segment to be demolished gradually reaches the edge of the concrete arch;

[0031] S53: Continue to adjust the hand chain hoists at both ends, and slowly lower the arch frame segment to be dismantled until the force on the hand chain hoists is completely transferred to the tower crane's wire rope.

[0032] Further optimization, step S6 includes the following specific steps:

[0033] S61: First, use a tower crane to lift the arch frame segment to be demolished to the top of the concrete arch;

[0034] S62: Subsequently, the workers at the top of the concrete arch released the hoist from the hanging point on the arch segment to be demolished;

[0035] S63: Finally, use a tower crane to lift the arch frame segment to be dismantled and transfer it to the bottom for storage.

[0036] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0037] 1. The present invention provides a method for dismantling a cast-in-place concrete arch support system with a suspended steel arch frame. The method uses a hanging steel wire rope as the hanging point in the dismantling process, which avoids the operation of reserving holes or embedding metal structures in the traditional anchor scheme, improves the integrity of the concrete arch structure after construction, and saves the process of repairing the reserved holes or embedded metal structures after the arch frame is dismantled.

[0038] 2. This invention provides a method for dismantling a cast-in-place concrete arch support system with a suspended steel arch frame. The method utilizes a combination of tower cranes, winches, and hand-operated hoists to allow the arch frame to be dismantled and moved laterally in sections at the bottom of the concrete arch. This dismantling method is more flexible and allows for the dismantling of one or more standard sections within the tower crane's load-bearing capacity.

[0039] 3. This invention provides a method for dismantling a cast-in-place concrete arch-supported steel arch system, utilizing a tower crane for transfer and hoisting. The arch frame can be stacked within the tower crane's operating radius. Compared to the method of in-situ lowering and stacking, this method has lower requirements for construction road conditions and terrain, and can effectively avoid the impact of rivers and canyons on the dismantling work.

[0040] 4. The method for dismantling a cast-in-place concrete arch-supported steel arch system provided by this invention utilizes tower cranes, winches, and hand-operated hoists, all of which are commonly used on construction sites. Using these devices to lift the dismantled arch segments results in lighter weight, eliminating the need for additional large-scale hoisting equipment on-site.

[0041] 5. The present invention provides a method for dismantling a cast-in-place concrete arch support system with a suspended steel arch frame. A safety wire rope system is installed to hold the suspended steel arch frame in place by the already cast-in-place concrete arch structure, preventing the arch frame from collapsing. This method eliminates the need for suspension towers and cables, thus avoiding interference with the construction of the superstructure caused by retaining such structures, as well as the increased costs associated with restoring them. Furthermore, the arch frame dismantling operation does not encroach on adjacent work surfaces.

[0042] 6. The present invention provides a method for dismantling a cast-in-place concrete arch cantilever steel arch support system, which sets up a semi-circular pipe protection system to avoid the steel wire rope and the concrete corners squeezing each other, effectively protecting the finished concrete from damage during the dismantling process. Attached Figure Description

[0043] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0044] Figure 1 A schematic diagram showing the distribution of the safety wire rope, the hoisting wire rope, and the tower base provided by this invention;

[0045] Figure 2 A schematic diagram illustrating the installation of the safety wire rope provided by this invention;

[0046] Figure 3 This is a schematic diagram illustrating the installation of the hoisting wire rope provided by the present invention;

[0047] Figure 4 This is a schematic diagram of the semi-circular tube protection device provided by the present invention;

[0048] Figure 5 This is a schematic diagram of the winch system layout provided by the present invention;

[0049] Figure 6 This is a schematic diagram of the hoist system reinforcement provided by the present invention;

[0050] Figure 7 This is a cross-sectional schematic diagram of the process of releasing the suspending wire rope at the arch frame segment to be dismantled, as provided by the present invention.

[0051] Figure 8 The front view (left side) and sectional view (right side) of the completed installation of the hand-operated hoist at the arch frame segment to be dismantled, provided by the present invention.

[0052] Figure 9The front view (left side) and sectional view (right side) of the completed connection between the winch and the tower crane lifting point provided by the present invention;

[0053] Figure 10 The front view (left side) and sectional view (right side) of the arch frame segment to be dismantled provided by the present invention after it has been lowered and adjusted to be horizontal in the air;

[0054] Figure 11 A cross-sectional view provided by the present invention showing the lateral displacement of the arch frame segment to be demolished toward the edge of the concrete arch;

[0055] Figure 12 A cross-sectional view provided by the present invention after the lifting point is transferred from the hand-operated hoist to the tower crane;

[0056] Figure 13 The tower crane provided for this invention lifts the arch frame segment to be dismantled to the top of the concrete arch in a front view (left side) and a cross-sectional view (right side).

[0057] Figure 14 The front view (left) and sectional view (right) of the hand chain hoist and winch after the binding nodes on the arch frame segment to be dismantled are provided by the present invention.

[0058] Figure 15 This is a cross-sectional view of a tower crane hoisting and transferring an arch frame segment to be dismantled, as provided in this invention.

[0059] The attached diagram shows the markings and corresponding component names:

[0060] 1. Concrete arch; 2. Suspended steel arch frame; 201. Horizontal scissor bracing; 202. Arch frame segment to be demolished; 203. Arch frame not yet demolished; 3. Safety wire rope; 4. Hoisting wire rope; 5. Tower crane; 6. Semicircular pipe protection device; 601. Semicircular steel pipe; 602. Cement nail; 7. Wire rope clip; 8. Winch system; 801. Winch; 802. Winch wire rope; 803. Directional pulley; 804. Anchor bar; 9. Hand chain hoist; 10. Tower crane wire rope. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0062] Example:

[0063] This embodiment provides a method for dismantling a cast-in-place concrete arch cantilevered steel arch support system, such as... Figures 1-15 As shown, the specific steps include the following:

[0064] 1. Install safety wire rope 3:

[0065] like Figure 1 and Figure 2 As shown, small tower cranes 5 are erected at both ends of the concrete arch 1. Before dismantling, safety wire ropes 3 need to be arranged along the entire arch of the suspended steel arch frame 2 at certain intervals. The safety wire ropes 3 pass under the upper chord of the suspended steel arch frame 2 at the bottom of the concrete arch 1, and are pulled upwards and tightened at both ends. The concrete arch 1 and the suspended steel arch frame 2 are tied together by the safety wire ropes 3 to form a safety system. The two ends of the safety wire ropes 3 are connected to the concrete arch 1 using multiple wire rope clips 7.

[0066] like Figure 4 As shown, semi-circular tube protective devices 6 are installed at the four corners where the safety wire rope 3 contacts the concrete arch 1 to cover the sharp corners and prevent wear on the safety wire rope 3 or damage to the concrete arch 1. The semi-circular tube protective device 6 includes a semi-circular steel pipe 601 and several cement nails 602, which fix the semi-circular steel pipe 601 to the concrete arch 1.

[0067] 2. Install 4 hoisting wire ropes:

[0068] like Figure 1 and Figure 3 As shown, a hoisting steel wire rope 4 is installed at the top of the suspended steel arch frame 2 according to the dismantling segmentation (for example, the single-section dismantling part is arranged at a spacing of about 4m, and the double-section dismantling part is arranged at a spacing of about 8m). The hoisting steel wire rope 4 is arranged around the concrete arch 1 and connected by multiple steel wire rope clips 7.

[0069] like Figure 4 As shown, referring to the method of setting up semi-circular pipe protection devices 6 to cover the sharp corners in step 1, the lifting wire rope 4 is protected. Semi-circular pipe protection devices 6 are installed at the four corners where the lifting wire rope 4 contacts the concrete arch 1 to cover the sharp corners, preventing wear on the lifting wire rope 4 or damage to the concrete arch 1. The semi-circular pipe protection device 6 includes a semi-circular steel pipe 601 and several cement nails 602, which fix the semi-circular steel pipe 601 to the concrete arch 1.

[0070] 3. Install multiple chain hoists as fall protection:

[0071] A hand-operated hoist 9 is hung on each hoisting wire rope 4. The hand-operated hoist 9 is fixed to the upper chord of the arch frame unit where the arch frame segment 202 to be demolished is located, as a fall protection insurance.

[0072] 4. For example Figure 7 As shown, release the safety wire rope 3 of the arch frame unit where the arch frame segment 202 to be dismantled is located, release the arch frame unit where the arch frame segment 202 to be dismantled is located, and then repeat step S1 to restore the safety wire rope 3 of the arch frame 203 that has not been dismantled.

[0073] 5. Install the winch system 8:

[0074] like Figure 5 As shown, a winch system 8 is installed on the top of the corresponding concrete arch 1 above the arch segment 202 to be demolished. The winch system 8 includes a winch 801, a winch wire rope 802, and a reversing pulley 803. By changing the direction of the winch wire rope 802 through the reversing pulley 803, a horizontal lateral force is applied to the arch segment 202 to be demolished.

[0075] like Figure 6 As shown, multiple anchor bars 804 are installed at the bottom of the winch 801. The anchor bars 804 are steel bars with a diameter of not less than 20mm. The lower part of the anchor bars 804 is anchored into the concrete arch 1, and the upper part is welded and fixed to the winch 801.

[0076] 6. The demolition of arch frame segment 202, if... Figures 8 to 15 As shown:

[0077] Step 6.1: As Figure 8 As shown, a hand-operated hoist 9 is installed before and after the arch frame segment 202 to be dismantled. The upper part of the hand-operated hoist 9 is hung on the hoisting wire rope 4, and the lower part is hung on the upper chord of the arch frame segment 202 to be dismantled. At the same time, a hand-operated hoist 9 is installed as a safety device on the undismantled arch frame 203 where the arch frame segment 202 to be dismantled is located.

[0078] Step 6.2: As Figure 9 As shown, tighten the three hand chain hoists 9 that were hung in step 6.1, and pull the winch wire rope 802 to fix it to the corresponding two hand chain hoists 9 of the arch frame segment 202 to be demolished. Finally, pull the tower crane wire rope 10 to the lifting point position of the arch frame segment 202 to be demolished and make a connection.

[0079] Step 6.3: As Figure 10 As shown, the corresponding pins and horizontal scissor braces 201 between the arch frame segment 202 to be dismantled and the arch frame 203 not dismantled are removed. Then, the hand-operated hoist 9 is slowly adjusted so that the arch frame segment 202 to be dismantled is slowly lowered and adjusted to be horizontal in the air.

[0080] Step 6.4: As Figure 11 As shown, after the entire system stabilizes, start the winch system 8 to retract the winch wire rope 802. Change the direction of the winch wire rope 802 through the reversing pulley 803 to apply a horizontal lateral force to the arch frame segment 202 to be demolished, so that the arch frame segment 202 to be demolished moves towards the edge of the concrete arch 1. During this process, pay attention to the movement status of the arch frame segment 202 to be demolished at any time to avoid violent shaking.

[0081] Step 6.5: As Figure 12As shown, after the arch frame segment 202 to be demolished reaches the edge of the concrete arch 1, continue to operate the hand chain hoist 9 and slowly lower the arch frame segment 202 to be demolished until the force of the hand chain hoist 9 is completely transferred to the tower crane 5 and the tower crane wire rope 10.

[0082] Step 6.6: As Figure 13 As shown, tower crane 5 is used to lift the arch frame segment 202 to be demolished to the top of the concrete arch 1.

[0083] Step 6.7: As Figure 14 As shown, workers at the top of the concrete arch 1 release the hoist 9 from its attachment point on the arch segment 202 to be demolished.

[0084] Step 6.8: As Figure 15 As shown, tower crane 5 is used to lift the arch frame segment 202 to be dismantled and transfer it to the ground for storage.

[0085] Step 7: Repeat steps 3 to 6 to dismantle the remaining suspended steel arch frames column by column.

[0086] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A cast-in-situ concrete arch suspended steel arch frame support system dismantling method, characterized in that, The method comprises the following steps: S1: a plurality of safety steel wires (3) are arranged along the length direction of the cantilevered steel arch frame (2) in sequence and at intervals, and the safety steel wires (3) are arranged at each arch unit and are used for connecting the arch unit and the concrete arch (1); S2: a sling steel wire (4) is arranged at the arch unit to be removed, and the sling steel wire (4) is connected around the upper concrete arch (1); S3: in the arch unit to be removed, the first arch segment (202) to be removed at the column end is disconnected from the safety steel wire (3), and the safety steel wire (3) is kept connected with the unremoved column arch (203); S4: a winch system (8) is arranged on the concrete arch (1), a winch steel wire (802) of the winch system (8) is connected with the side and the arch segment (202) to be removed, so that the winch steel wire (802) can exert a horizontal moving force on the arch segment (202) to be removed; a hand-operated hoist (9) is arranged at both ends of the arch segment (202) to be removed, so that the hand-operated hoist (9) is connected with the arch segment (202) to be removed and the sling steel wire (4) respectively; and a tower crane steel wire (10) of a tower crane (5) is connected with a lifting point of the arch segment (202) to be removed; S5: the connection between the arch segment (202) to be removed and the unremoved column arch (203) is removed, and the arch segment (202) to be removed is pulled to the edge of the concrete arch (1) through the cooperation of the winch system (8) and the hand-operated hoist (9); S6: then, the arch segment (202) to be removed is hoisted out and stored through the tower crane steel wire (10); S7: steps S3-S6 are repeated until all the arch units to be removed in one column are removed; S8: steps S2-S7 are repeated to remove each arch unit in column until the whole cantilevered steel arch frame (2) is removed.

2. The cast-in-situ concrete arch suspended spliced steel arch support system dismantling method according to claim 1, characterized in that, In step S1, when the safety steel wire (3) is connected, the safety steel wire (3) is passed from below the top chord of the cantilevered steel arch frame (2) along the column direction, and the two ends are pulled up to be tightened around the concrete arch (1) to bundle the concrete arch (1) and the cantilevered steel arch frame (2) together to form a safety system through the safety steel wire (3).

3. The cast-in-situ concrete arch suspended spliced steel arch support system dismantling method according to claim 2, characterized in that, In the connection process of the safety steel wire (3) and the sling steel wire (4), a semicircular pipe protection device (6) is arranged at the four corner positions where the two wires contact the concrete arch (1), and the semicircular pipe protection device (6) comprises a semicircular steel pipe (601), and both wires pass through or contact the semicircular steel pipe (601); The two ends of the semicircular steel pipe (601) are connected with the adjacent two sides of the concrete arch (1).

4. The cast-in-situ concrete arch suspended spliced steel arch support system dismantling method according to claim 1, characterized in that, In step S2, after the sling steel wire (4) is installed, a hand-operated hoist (9) is hung between the sling steel wire (4) and the arch unit to be removed to serve as a falling prevention safety device.

5. The cast-in-situ concrete arch suspended spliced steel arch support system dismantling method according to claim 1, characterized in that, The winch system (8) comprises a winch (801) and a base, the winch (801) is fixed on the top surface of the concrete arch (1) through the base, and the base is anchored into the concrete arch (1) through a plurality of anchor bars (804).

6. The cast-in-situ concrete arch suspended spliced steel arch support system dismantling method according to claim 5, characterized in that, The diameter of the anchor bar (804) is not less than 20mm.

7. The cast-in-place concrete arch suspension splicing steel arch support system dismantling method according to any one of claims 1-6, characterized in that, The winch system (8) further comprises a change direction fixed pulley (803), the change direction fixed pulley (803) is installed at the upper and lower end positions of the side surface of the concrete arch (1), and the winch steel wire rope (802) is connected in sequence through the upper and lower two change direction fixed pulleys (803) and the arch frame segment (202) to be removed.

8. The cast-in-situ concrete arch suspension splicing steel arch support system dismantling method according to any one of claims 1-6, characterized in that, In step S4, after the hand-operated hoist (9) is arranged at both ends of the arch frame segment (202) to be removed, the hand-operated hoist (9) is further arranged on the unremoved arch frame (203) behind the arch frame segment (202) to be removed, and the unremoved arch frame (203) is connected with the sling steel wire rope (4).

9. The cast-in-place concrete arch suspension splicing steel arch support system dismantling method according to any one of claims 1-6, characterized in that, The step S5 comprises the following specific steps: S51: the corresponding pin shafts between the arch frame segment (202) to be removed and the unremoved arch frame (203) and the flat link cross brace (201) are removed to disconnect the connection between the arch frame segment (202) to be removed and the unremoved arch frame (203); then, the hand-operated hoist (9) at both ends is slowly adjusted to slowly lower the arch frame segment (202) to be removed and adjust it to be horizontal in the air; S52: then, the winch system (8) is started to apply a horizontal moving force to the arch frame segment (202) to be removed, so that the arch frame segment (202) to be removed gradually reaches the edge of the concrete arch (1); S53: the hand-operated hoist (9) at both ends is continuously adjusted to slowly lower the arch frame segment (202) to be removed until the stress of the hand-operated hoist (9) is completely transferred to the tower crane steel wire rope (10) of the tower crane (5).

10. The cast-in-place concrete arch suspension splicing steel arch support system dismantling method according to any one of claims 1-6, characterized in that, The step S6 comprises the following specific steps: S61: the arch frame segment (202) to be removed is first lifted to the top of the concrete arch (1) by the tower crane (5); S62: then, the workers at the top of the concrete arch (1) remove the hanging point of the hand-operated hoist (9) on the arch frame segment (202) to be removed; S63: finally, the arch frame segment (202) to be removed is lifted and transported by the tower crane (5) and is stored on the bottom surface.

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