Dismounting-free quick mounting construction method for ultra-deep foundation pit supporting structure

Abstract

The invention relates to the technical field of deep foundation pit supporting, in particular to a disassembly-free quick mounting construction method for an ultra-deep foundation pit supporting structure. By means of the construction method, automatic support replacement can be achieved, manpower is saved, the construction efficiency is higher, in the construction process, staggered support replacement is achieved through cooperation of the lifting mechanism and the traction mechanism, and the stability of the later construction section is higher; meanwhile, the cost of large machines and tools and the construction cost are reduced.

Description

Technical Field

[0001] The invention relates to the technical field of deep foundation pit support, and in particular to a disassembly-free rapid installation construction method for an ultra-deep foundation pit support structure. Background Art

[0002] In the process of open-cut construction of existing tunnels, pipe corridors, and subways, in order to prevent the collapse of the deep foundation pit slope, the crown beam + steel support system is used to apply prestress to support the deep foundation pit. Due to site restrictions, such municipal projects often adopt segmented construction. After the strength of the bottom plate of the construction section reaches the requirement, the support system at the bottom of the deep foundation pit is manually dismantled. The steel support and steel purlin are then hoisted to the next section of the foundation pit by a crane as turnover materials. They are manually reassembled and prestressed, which requires a lot of manpower and material resources. Multiple supports are set up for ultra-deep foundation pits. During the hoisting process, there is a risk of collision between the crown beam at the top of the foundation pit and the steel support and steel purlin, which can easily cause damage to the steel support system. In order to prevent the steel support system from being damaged, multiple people are required to assist in the hoisting process, which seriously reduces the construction efficiency. In addition, the use of large machinery at the edge of ultra-deep foundation pits is extremely dangerous. Summary of the invention

[0003] The present invention aims to solve the above-mentioned technical problems, thereby providing a disassembly-free rapid installation construction method for an ultra-deep foundation pit support structure, which greatly reduces the danger during the construction process and greatly improves the construction efficiency.

[0004] The present invention is to solve the above problems, and its specific scheme is: A method for quick installation and construction of an ultra-deep foundation pit support structure without disassembly, comprising the following steps: S1. Unloading the fourth support prestress After the concrete strength of the bottom slab of the first construction section reaches the requirement, remove the movable steel plate between the steel purlin and the retaining pile of the fourth support of the first construction section; S2. Excavation of the rear construction section, installation of triangular supports and lifting mechanisms After the strength of the crown beam of the rear construction section reaches the requirement, the earthwork of the rear construction section is excavated to the bottom of the second support, and a triangular support is installed on the retaining pile at the second support position of the rear construction section. The intersection of the first construction section and the rear construction section is excavated by slope cutting, and a lifting mechanism is installed on the crown beam at the intersection of the first construction section and the rear construction section. S3, the fourth support of the first group of construction sections is moved horizontally once A traction mechanism is set up in the rear construction section, and the hook of the traction mechanism is connected to the end of the steel perimeter purlin of the first group of the fourth support of the first construction section, and the fourth support of the first group of the first construction section is pulled to the triangular support under the lifting mechanism; S4, the fourth support of the first construction section is vertically lifted The lifting mechanism lifts the fourth support of the first group of the first construction section upwards, and stops lifting after the fourth support of the first group of the first construction section reaches the same height as the second support of the rear construction section; S5, the first group of the fourth support of the first construction section is moved horizontally for the second time The traction mechanism pulls the fourth support of the first group of construction sections to the triangular support at the second support position of the rear construction section, resets the lifting mechanism, and completes the replacement of the fourth support of the first group of construction sections; S6. Complete the replacement of the fourth support of the remaining construction section The hook of the traction mechanism hooks the fourth support of the next group of first construction sections, and completes the replacement construction of the fourth support of the remaining first construction sections according to steps S3-S5, removes the triangular support at the fourth support of the first construction section, and applies the prestress of the second support of the later construction section; S7, continue excavation of the rear construction section and install triangular supports The earthwork of the rear construction section is excavated to the position below the third support, and triangular supports are installed on the retaining piles at the position of the third support of the rear construction section; S8, first construction section third support replacement Take out the movable steel plate between the steel purlin and the retaining pile of the third support of the first construction section, and the traction mechanism will pull the third support of each group of the first construction section to the third support position of the later construction section in turn, completing the replacement of the third support of the first construction section; remove the triangular support at the third support of the first construction section, and apply prestress to the third support of the later construction section; S9, continue excavation of the rear construction section and install triangular supports The earthwork of the rear construction section is excavated to the position below the fourth support, and triangular supports are installed on the retaining piles at the fourth support position of the rear construction section; S10, the second support of the first construction section is moved horizontally once Take out the movable steel plate between the steel purlin of the second support of the first construction section and the retaining pile, connect the hook of the traction mechanism to the end of the steel purlin of the second support of the first construction section, and pull the second support of the first construction section to the triangular support under the lifting mechanism; S11, the second support of the first construction section is lowered vertically The lifting mechanism lowers the second support of the first group of the first construction section downwards, and stops lifting after the second support of the first group of the first construction section reaches the same height as the fourth support of the rear construction section; S12, the second support of the first construction section is moved horizontally for the second time The traction mechanism pulls the second support of the first group of construction sections to the triangular support of the fourth support of the subsequent construction section, and the lifting mechanism is reset to complete the replacement of the second support of the first group of construction sections; S13, complete the replacement of the second support of the remaining construction section The hook of the traction mechanism hooks the second support of the next group of the first construction section, and completes the replacement construction of the second support of the remaining first construction section according to the steps S10-S12, removes the triangular support at the second support of the first construction section, and applies prestress to the fourth support of the subsequent construction section.

[0005] Compared with the prior art, the present invention using the above technical solution has the following beneficial effects: Through the construction method of the present invention, automatic support replacement can be achieved, manpower can be saved, and construction efficiency is higher. During the construction process, staggered support replacement is achieved through the cooperation of the lifting mechanism and the traction mechanism, making the stability of the subsequent construction section stronger; at the same time, the cost of large machinery and equipment is reduced, and the construction cost is reduced.

[0006] Preferably, a further technical solution of the present invention is: The triangular support comprises a bracket with a triangular cross section, a roller seat and a roller. The bracket is installed on the inner wall of the guard pile, the roller seat is fixed on the bracket, and the roller is installed on the roller seat. The roller rolls against the steel purlin.

[0007] The traction mechanism includes a first electric hoist, a first fixed pulley, a second fixed pulley, a third fixed pulley and a hook. The first electric hoist is installed on the crown beam of the rear construction section, the first fixed pulley is installed on the guardrail piles at the second steel guardrail purlin, the third steel guardrail purlin or the fourth steel guardrail purlin of the rear construction section, the second fixed pulley is installed on the guardrail piles at the same height as the second steel guardrail purlin below the lifting mechanism, the third fixed pulley is installed on the guardrail piles at the same height as the fourth steel guardrail purlin below the lifting mechanism, and the hook is used to connect the steel wire rope and the steel guardrail purlin.

[0008] The lifting mechanism comprises a second electric hoist and a hook. The second electric hoist is arranged on the crown beam at the junction of the first construction section and the second construction section. The second electric hoist is connected to the steel surrounding purlin through the hook.

[0009] The steel purlin is a double-jointed structure, including a steel section and a side plate, and the side plate is fixedly connected to both sides of two steel sections. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic side view of an ultra-deep foundation pit support according to an embodiment of the present invention; Figure 2 yes Figure 1 A partial enlarged view of A; Figure 3 is a schematic diagram of vertical lifting of a steel support according to an embodiment of the present invention; Figure 4 is a schematic diagram of the arrangement of a lifting mechanism according to an embodiment of the present invention; Figure 5 Schematic diagram of a traction mechanism connected to a steel purlin according to an embodiment of the present invention; Figure 6 This is a schematic diagram of installing a triangular support according to an embodiment of the present invention; Figure 7 This is a schematic diagram of a single lateral shift of the fourth support of the first group of first construction sections in an embodiment of the present invention; Figure 8 This is a schematic diagram showing the completion of the replacement of the fourth support of the first group of the first construction section in an embodiment of the present invention; Fig. 9 Schematic diagram of the transverse movement of the third support of the first construction section of an embodiment of the present invention; Fig.10 This is a schematic diagram of the completion of the replacement of the third support of the first construction section in an embodiment of the present invention; Fig.11 This is a schematic diagram of a single lateral movement of the second support of the first group of first construction sections in an embodiment of the present invention; Fig.12 Schematic diagram of vertically lowering the second support of the first group of first construction sections in an embodiment of the present invention; Fig.13 This is a schematic diagram of the completion of the replacement of the support in the first construction section of the embodiment of the present invention; In the figure: supporting structure 1; crown beam 1-1; second support 1-2; third support 1-3; fourth support 1-4; steel support 1-2-1; steel purlin 1-2-2; movable steel plate 1-2-3; reserved holes 1-2-4; handle 1-2-5; retaining pile 2; first construction section bottom plate 3; triangular support 4; bracket 4-1; roller 4-2; expansion screw 4-3; lifting mechanism 5; crossbeam 5-1; second electric hoist 5-2; hook 5-3; traction mechanism 6; first electric hoist 6-1; wire rope 6-2; hook 6-3; first fixed pulley 6-4; second fixed pulley 6-5; third fixed pulley 6-6; rear construction section 7; first construction section 8. DETAILED DESCRIPTION

[0011] The present invention will be further described below in conjunction with embodiments, the purpose of which is only to provide a better understanding of the content of the present invention. Therefore, the examples given do not limit the protection scope of the present invention.

[0012] See attached Figure 1-13 The embodiment of the present invention discloses a method for quick installation and construction of an ultra-deep foundation pit support structure without disassembly, comprising the following steps: S1. Unloading the fourth support prestress The ultra-deep foundation pit is divided into multiple construction sections. The construction of the retaining structure has been completed in construction section 8. The retaining structure consists of a support structure 1 and retaining piles 2. The support structure 1 is mainly composed of a crown beam 1-1, a second support 1-2, a third support 1-3 and a fourth support 1-4. The second support 1-2, the third support 1-3 and the fourth support 1-4 have the same structure. The second support 1-2 consists of a steel support 1-2-1, a steel purlin 1-2-2 and a movable steel plate 1-2-3. The steel support 1-2-1 is supported by a steel pipe. The steel purlin 1-2-2 is a double-piece structure, which consists of two H-shaped steels and side plates. The side plates are welded on both sides of the two H-shaped steels. The inner side plates are welded and fixed to the steel supports, and the outer side plates are abutted against the movable steel plates 1-2-3. Reserved holes 1-2-4 and handles 1-2-5 are set at the ends of the steel purlin 1-2-2 for traction, lateral movement and hoisting. A plurality of triangular supports 4 are respectively installed on the inner wall of the retaining pile 2 at the second support 1-2, the third support 1-3 and the fourth support 1-4. The plurality of triangular supports 4 are equidistantly arranged and arranged horizontally. The triangular supports 4 are composed of a bracket 4-1, a roller seat and a roller 4-2. The cross section of the bracket 4-1 is triangular. The bracket 4-1 is installed on the retaining pile 2 through an expansion screw 4-3. The roller 4-2 is arranged on the upper part of the bracket 4-1 through a roller seat. The rolling surface of the roller rolls against the bottom surface of the steel purlin. A plurality of steel supports 1-2-1 are supported between two steel purlins 1-2-2 on opposite sides. The steel supports 1-2-1 are fixedly connected to the steel purlins 1-2-2 by bolts. A jack is provided at one end of the steel support 1-2-1. The jack is used to apply prestress. The two steel purlins 1-2-2 and the plurality of supports 1-2-1 form a support system. A movable steel plate 1-2-3 is provided between the side plate of the steel purlin 1-2-2 and the guard pile 2. The structures of the third support 1-3 and the fourth support 1-4 are exactly the same as the structure of the second support 1-2. After the fourth support 1-4 is installed, the bottom plate 3 of the first construction section is cast. After the concrete strength of the bottom plate 3 of the first construction section reaches the requirement, the movable steel plate 1-2-3 between the steel purlin 1-2-2 of the fourth support 1-4 and the retaining pile 2 is taken out. At this time, there is a certain distance between the fourth support 1-4 and the retaining pile 2, and the fourth support 1-4 is supported by the triangular support 4 to prevent the steel support system from falling.

[0013] S2: Excavation of earthwork in the rear construction section, installation of triangular supports and lifting mechanisms After the strength of the crown beam 1-1 of the rear construction section reaches the requirement, the earthwork of the rear construction section 7 is excavated until 50 cm below the second support 1-2, and a triangular support is installed at the position of the retaining pile 2 where the second support 1-2 of the rear construction section 7 is located. The slope is excavated at the junction of the first construction section 8 and the rear construction section 7. The earthwork of the rear construction section 7 is not excavated and the slope is excavated. After the excavation reaches the designed elevation, the lifting mechanism 5 is placed at the junction.

[0014] S3, the fourth support of the first group of construction section 8 is moved horizontally once A traction mechanism is provided at the rear construction section 7, and the traction mechanism mainly consists of a first electric hoist 6-1, a wire rope 6-2, a first fixed pulley 6-4, a second fixed pulley 6-5, a third fixed pulley 6-6 and a hook 6-3. The first electric hoist 6-1 is installed on the crown beam 1-1 of the rear construction section 7, one end of the wire rope 6-2 is wound around the drum of the first electric hoist 6-1, and the other end is connected to the hook 6-3. The first fixed pulley 6-4 is installed at the position of the retaining pile 2 where the second support 1-2 is installed in the rear construction section 7, and the third fixed pulley 6-6 is installed on the retaining pile 2 at the same height as the fourth support 1-4 below the lifting mechanism; The steel wire rope 6-2 passes over the first fixed pulley 6-4, the second fixed pulley 6-5 and the third fixed pulley 6-6, and the hook 6-3 is hooked on the reserved hole of the steel purlin of the fourth support 1-4 of the first construction section 8, and the first electric hoist 6-1 is started, and the entire support system of the fourth support 1-4 is horizontally pulled to the triangular support 4 at the junction through the top roller 4-2 of the triangular support 4, and the first electric hoist 6-1 is closed. At this time, the support system is located below the lifting mechanism.

[0015] S4, the fourth support of the first group of construction section 8 is vertically lifted The lifting mechanism 5 includes a crossbeam 5-1, a second electric hoist 5-2 and a hook 5-3. The second electric hoist 5-2 is mounted on two adjacent crown beams 1-1 of the rear construction section 7 through the crossbeam 5-1. Steel plates are arranged at both ends of the crossbeam 5-1 and are anchored on the crown beam 1-1 through multiple screws. The hook 5-3 of the lifting mechanism 5 hooks the handle of the fourth support of the first group of first construction section 8, starts the second electric hoist 5-2, lifts it up for a distance and then closes one second electric hoist 5-2, while the other second electric hoist 5-2 remains started, so that the fourth support 1-4 rotates along the steel support until the vertical projection of the fourth support 1-4 does not collide with the triangular support 4 at the junction and keeps a distance, starts the closed second electric hoist 5-2, and lifts the fourth steel support 1-4 together to above the triangular support 4 at the same height as the second support 1-2 at the junction of the first construction section 8 and the rear construction section 7, adjusts the second electric hoist 5-2, makes the fourth support 1-4 at the junction horizontal and places it on the roller 4-2 of the triangular support 4 at the junction.

[0016] S5, first construction section 8, the first group of the fourth support second horizontal shift Start the first electric hoist 6-1 to pull the fourth support 1-4 of the first group of construction section 8 to the triangular support 4 of the second support 1-2 of the rear construction section 7, and reset the hook 5-3 to complete the support replacement work of the fourth support 1-4 of the first group of construction section 8.

[0017] S6. Complete the replacement of the fourth support of the remaining construction section 8 The hook 6-3 of the traction mechanism 6 hooks the reserved holes of the fourth support 1-4 of the next group of the first construction section 8, and completes the support replacement construction of the remaining fourth supports 1-4 of the first construction section 8 according to steps S3-S5, removes the triangular support 4 at the fourth support 1-4 of the first construction section 8, and applies prestress to the second support 1-2 of the subsequent construction section 7.

[0018] S7, the excavation of the post-construction section 7 continues, and the triangular support is installed The earthwork of the rear construction section 7 is excavated to 50 cm below the third support 1-3, and triangular supports are installed on the retaining piles at the third support position of the rear construction section 7. The earthwork at the junction is not processed.

[0019] S8, first construct section 8, the third support is replaced Take out the movable steel plate between the steel purlin and the retaining pile 2 of the third support 1-3 of the first construction section 8, adjust the position of the first fixed pulley 6-4 to the position of the retaining pile 2 of the third support 1-3 of the rear construction section 7, and the traction mechanism 6 will pull each group of the third support 1-3 of the first construction section 8 to the position of the third support 1-3 of the rear construction section 7 in turn to complete the support replacement work of the third support 1-3 of the first construction section 8; remove the triangular support 4 at the third support 1-3 of the first construction section 8, and apply prestress to the third support 1-3 of the rear construction section 7.

[0020] S9, the excavation of the post-construction section 7 continues, and the triangular support is installed The earthwork of the rear construction section 7 is excavated to 50 cm below the fourth support 1-4, and the triangular support 4 is installed on the retaining pile 2 at the position of the fourth support 1-4 of the rear construction section 7.

[0021] S10, the second support of the first group of construction section 8 is moved horizontally once Adjust the position of the first fixed pulley 6-4 to the position of the retaining pile 2 of the fourth support 1-4 of the rear construction section 7, take out the movable steel plate between the steel purlin of the second support 1-2 of the first construction section 8 and the retaining pile 2, and the steel wire rope 6-2 passes around the first fixed pulley 6-4, the third fixed pulley 6-6 and the second fixed pulley 6-5, and hook the hook 6-3 to the reserved hole 1-2-4 of the steel purlin of the second support 1-2 of the first construction section 8, start the first electric hoist 6-1, and pull the entire support system of the second support 1-2 horizontally to the triangular support 4 at the junction through the top roller 4-2 of the triangular support 4, and close the first electric hoist 6-1. At this time, the support system is located below the lifting mechanism.

[0022] S11, the second support of the first group of construction section 8 is lowered vertically The hook 5-3 of the lifting mechanism 5 hooks the handle 1-2-5 of the second support 1-2 of the first group of the first construction section 8, starts the second electric hoist 5-2, and after lowering it for a distance, close one second electric hoist 5-2, and keep the other second electric hoist 5-2 started, so that the second support 1-2 rotates along the steel support 1-2-1 until the vertical projection of the fourth support 1-4 does not collide with the triangular support 4 at the junction and maintains a distance, starts the closed second electric hoist 5-2, and lowers the second steel support 1-2 together to above the triangular support 4 at the same height position of the fourth support 1-4 at the junction of the first construction section 8 and the rear construction section 7, adjusts the second electric hoist 5-2 to make the second support 1-2 at the junction horizontal and place it on the roller 4-2 of the triangular support 4 at the junction.

[0023] S12, the second support of the first group of construction section 8 is moved horizontally for the second time Start the first electric hoist 6-1 to pull the second support 1-2 of the first group of first construction section 8 to the triangular support 4 of the fourth support 1-4 of the rear construction section 7, and reset the hook 5-3 to complete the support replacement work of the second support 1-2 of the first group of first construction section 8.

[0024] S13, complete the replacement of the second support of the remaining construction section 8 The hook 6-3 of the traction mechanism 6 hooks the reserved holes of the fourth support 1-4 of the next group of the first construction section 8, and completes the replacement construction of the second support 1-2 of the remaining first construction section 8 according to steps S10-S12, removes the triangular support 4 at the second support 1-2 of the first construction section 8, and applies prestress to the fourth support 1-4 of the subsequent construction section 7.

[0025] Compared with the prior art, the present invention using the above technical solution has the following beneficial effects: Through the construction method of the present invention, automatic support replacement can be achieved, manpower can be saved, and construction efficiency is higher. During the construction process, staggered support replacement is achieved through the cooperation of the lifting mechanism and the traction mechanism, making the stability of the subsequent construction section stronger; at the same time, the cost of large machinery and equipment is reduced, and the construction cost is reduced.

[0026] The above description is only a preferred feasible embodiment of the present invention, and does not limit the scope of rights of the present invention. All equivalent changes made using the contents of the present specification and its drawings are included in the scope of rights of the present invention.

Claims

1. A method for quick installation and construction of an ultra-deep foundation pit support structure without disassembly, comprising the following steps: S1. Unloading the fourth support prestress After the concrete strength of the bottom slab of the first construction section reaches the requirement, remove the movable steel plate between the steel purlin and the retaining pile of the fourth support of the first construction section; S2: Excavation of earthwork in the rear construction section, installation of triangular supports and lifting mechanisms After the strength of the crown beam of the rear construction section reaches the requirement, the earthwork of the rear construction section is excavated to the bottom of the second support, and a triangular support is installed on the retaining pile at the second support position of the rear construction section. The intersection of the first construction section and the rear construction section is excavated by slope cutting, and a lifting mechanism is installed on the crown beam at the intersection of the first construction section and the rear construction section. S3, the fourth support of the first group of construction sections is moved horizontally once A traction mechanism is set up in the rear construction section, and the hook of the traction mechanism is connected to the end of the steel perimeter purlin of the first group of the fourth support of the first construction section, and the fourth support of the first group of the first construction section is pulled to the triangular support under the lifting mechanism; S4, the fourth support of the first construction section is vertically lifted The lifting mechanism lifts the fourth support of the first group of the first construction section upwards, and stops lifting after the fourth support of the first group of the first construction section reaches the same height as the second support of the rear construction section; S5, the first group of the fourth support of the first construction section is moved horizontally for the second time The traction mechanism pulls the fourth support of the first group of construction sections to the triangular support at the second support position of the rear construction section, resets the lifting mechanism, and completes the replacement of the fourth support of the first group of construction sections; S6. Complete the replacement of the fourth support of the remaining construction section The hook of the traction mechanism hooks the fourth support of the next group of first construction sections, and completes the replacement construction of the fourth support of the remaining first construction sections according to steps S3-S5, removes the triangular support at the fourth support of the first construction section, and applies the prestress of the second support of the later construction section; S7, continue excavation of the rear construction section and install triangular supports The earthwork of the rear construction section is excavated to the position below the third support, and triangular supports are installed on the retaining piles at the position of the third support of the rear construction section; S8, first replace the third support of the construction section Take out the movable steel plate between the steel purlin and the retaining pile of the third support of the first construction section, and the traction mechanism will pull the third support of each group of the first construction section to the third support position of the later construction section in turn, completing the replacement of the third support of the first construction section; remove the triangular support at the third support of the first construction section, and apply prestress to the third support of the later construction section; S9, continue excavation of the rear construction section and install triangular supports The earthwork of the rear construction section is excavated to the position below the fourth support, and triangular supports are installed on the retaining piles at the fourth support position of the rear construction section; S10, the second support of the first construction section is moved horizontally once Take out the movable steel plate between the steel purlin of the second support of the first construction section and the retaining pile, connect the hook of the traction mechanism to the end of the steel purlin of the second support of the first construction section, and pull the second support of the first construction section to the triangular support under the lifting mechanism; S11, the second support of the first construction section is lowered vertically The lifting mechanism lowers the second support of the first group of the first construction section downwards, and stops lifting after the second support of the first group of the first construction section reaches the same height as the fourth support of the rear construction section; S12, the second support of the first construction section is moved horizontally for the second time The traction mechanism pulls the second support of the first group of construction sections to the triangular support of the fourth support of the subsequent construction section, and the lifting mechanism is reset to complete the replacement of the second support of the first group of construction sections; S13, complete the replacement of the second support of the remaining construction section The hook of the traction mechanism hooks the second support of the next group of the first construction section, and completes the replacement construction of the second support of the remaining first construction section according to the steps S10-S12, removes the triangular support at the second support of the first construction section, and applies prestress to the fourth support of the subsequent construction section.

2. The method for quick installation of ultra-deep foundation pit support structure without disassembly according to claim 1 is characterized by: The triangular support comprises a bracket with a triangular cross section, a roller seat and a roller. The bracket is installed on the inner wall of the guard pile, the roller seat is fixed on the bracket, and the roller is installed on the roller seat. The roller rolls against the steel purlin.

3. The method for quick installation of ultra-deep foundation pit support structure without disassembly according to claim 1 is characterized in that: The traction mechanism includes a first electric hoist, a first fixed pulley, a second fixed pulley, a third fixed pulley and a hook. The first electric hoist is installed on the crown beam of the rear construction section, the first fixed pulley is installed on the guardrail piles at the second steel guardrail purlin, the third steel guardrail purlin or the fourth steel guardrail purlin of the rear construction section, the second fixed pulley is installed on the guardrail piles at the same height as the second steel guardrail purlin below the lifting mechanism, the third fixed pulley is installed on the guardrail piles at the same height as the fourth steel guardrail purlin below the lifting mechanism, and the hook is used to connect the steel wire rope and the steel guardrail purlin.

4. The method for quick installation of ultra-deep foundation pit support structure without disassembly according to claim 1 is characterized in that: The lifting mechanism comprises a second electric hoist and a hook. The second electric hoist is arranged on the crown beam at the junction of the first construction section and the second construction section. The second electric hoist is connected to the steel surrounding purlin through the hook.

5. The method for quick installation of ultra-deep foundation pit support structure without disassembly according to claim 1 is characterized in that: The steel purlin is a double-jointed structure, including a steel section and a side plate, and the side plate is fixedly connected to both sides of two steel sections.

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