Fabricated steel support structure for large-span deep foundation pit earth excavation of airport

Abstract

The invention relates to the field of earthwork excavation, and discloses an assembly type steel supporting structure for large-span deep foundation pit earthwork excavation of an airport, the assembly type steel supporting structure comprises a steel enclosing purlin, a steel bracket, a steel supporting pipe, a movable head and a supporting frame, the movable head abuts against the steel bracket, the steel bracket comprises a vertical back plate and a transverse supporting plate, a centering mechanism is installed on the vertical back plate, and the transverse supporting plate is installed on the transverse supporting plate. The centering mechanism is used for centering the steel stay pipe on the steel bracket; the centering mechanism comprises two sets of edge pushing assemblies which are symmetrically installed on the two sides of the vertical back plate, and the movable head is located between the edge pushing assemblies on the two sides. And the pull-up assembly is arranged in the middle position between the two side edge pushing assemblies and installed on the side wall, away from the movable head, of the vertical back plate, the fixed position of the pull-up assembly is located at the position where the vertical back plate stretches out to the position above the steel enclosing purlin, and the pull-up assembly is used for synchronizing the two side edge pushing assemblies to get close to each other or get away from each other. According to the invention, the centering positioning problem when the steel stay pipe is mounted on the steel bracket can be effectively solved, and the stability and safety of a support system are improved.

Description

Technical Field

[0001] The present application relates to the field of earth excavation, and in particular to an assembled steel support structure for earth excavation of a large-span deep foundation pit of an airport. Background Art

[0002] In the construction of large-scale projects such as airports and subway stations, the excavation and support of large-span deep foundation pits are critical to ensuring construction safety. Prefabricated steel support structures are widely used in deep foundation pit support projects due to their advantages such as rapid construction and reusability. Traditional steel support structures typically consist of steel support pipes, steel purlins, and steel brackets. Steel purlins are constructed on the side walls of the foundation pit, and steel brackets are installed on them. The ends of the steel support pipes are mounted on the steel brackets on both sides of the foundation pit, forming lateral support for the side walls of the foundation pit to resist soil pressure and control foundation pit deformation.

[0003] However, in the process of implementing relevant technical solutions, at least the following technical problems were found: when the assemblers hoisted the steel support pipe onto the steel bracket, it was difficult for the assemblers to observe the position of the steel support pipe on the steel bracket with the naked eye, and the steel support pipe was difficult to be centered on the steel bracket, resulting in an offset. Due to the heavy weight of the steel support pipe, the assemblers would no longer move the steel support pipe to center it, resulting in local stress concentration on the steel bracket when the steel support pipe applied lateral support to the steel bracket. Under the action of long-term eccentric loads, the welds, bolted joints or local steel plates of the steel bracket may crack, deform or even suffer brittle failure due to stress concentration, affecting the overall stability of the support system. Under dynamic loads, such as excavator vibration and earth excavation impact, the eccentric support may become unstable, and in severe cases may even cause the steel support to slip or collapse, threatening the safety of the foundation pit. Summary of the Invention

[0004] This application solves the technical problem in the prior art that the steel support pipes in the prefabricated steel support structure are difficult to install in the center, which easily leads to eccentric loads and instability of the support system, by providing an assembled steel support structure for earth excavation of large-span deep foundation pits at airports. It effectively solves the problem of centering the steel support pipes when installing them on steel brackets, thereby improving the stability and safety of the support system.

[0005] The present application provides an assembled steel support structure for earthwork excavation of a large-span deep foundation pit of an airport, comprising a steel purlin constructed on the side wall of the foundation pit, a steel bracket fixed on the steel purlin, a steel support pipe placed on the steel bracket, a movable head installed on the end of the steel support pipe, and a support frame for supporting the steel support pipe, wherein the movable head abuts against the steel bracket, and the steel bracket comprises a vertical back plate fixed on the steel purlin and a horizontal support plate perpendicular to the vertical back plate, a centering mechanism is installed on the vertical back plate, and the centering mechanism is used to center the steel support pipe at On the steel bracket, the top edge of the vertical back plate extends above the steel purlin; the centering mechanism includes: side pushing components, which are provided in two groups and symmetrically installed on both sides of the vertical back plate, and the movable head is located between the side pushing components on both sides; the upper pulling component is provided in the middle position between the side pushing components on both sides, and is installed on the side wall of the vertical back plate away from the movable head, and the fixed position of the upper pulling component is located at the position where the vertical back plate extends above the steel purlin, and the upper pulling component is used to synchronize the side pushing components on both sides to approach or move away from each other.

[0006] Furthermore, the side push assembly includes: a vertical push plate, which is vertically arranged above the cross support plate and is used to abut against the active head; an adapter block, which is fixedly connected to the side wall of the vertical back plate that abuts against the active head and is close to the side edge of the vertical back plate, and the adapter blocks are correspondingly provided at both ends of the vertical push plate; a connecting rod group, a connecting rod group is provided between the two ends of the vertical push plate and the two adapter blocks, and the two groups of connecting rod groups are used to push the vertical push plate horizontally; wherein the vertical back plate is provided with a square hole at the top position of the vertical push plate, and the upper pull assembly is connected to the vertical push plate through the square hole.

[0007] Furthermore, the connecting rod group includes: connecting rod one, one end of which is hinged on the adapter block, and the other end faces the vertical push plate; connecting rod two, one end of which is hinged to the end of connecting rod one away from the adapter block, and the other end faces the vertical push plate; connecting rod three, one end of which is hinged to the end of connecting rod two away from the connecting rod two, and the other end is hinged to the vertical push plate, and connecting rod three is always parallel to connecting rod one.

[0008] Furthermore, a connecting rod is hinged between the second connecting rods in the two connecting rod groups at both ends of the vertical push plate.

[0009] Furthermore, a hinge groove is provided in the middle of the side wall of the vertical push plate near the end, and the connecting rod three is hinged in the hinge groove.

[0010] Furthermore, the pulling-up assembly includes: a slide rail fixed to the middle of the side wall of the vertical back plate; a slider slidably connected to the slide rail; two pull rods are provided and symmetrically arranged on both sides of the slider, and the two pull rods are respectively connected to the vertical push plates of the side push assemblies on both sides, one end of the pull rod is hinged to the slider, and the other end is hinged to the vertical push plate, and the hinge axis between the vertical push plate and the pull rod passes through the square hole of the vertical back plate; a pull rope, one end of which is fixed to the slider, and the other end is used for the assembler to pull up.

[0011] Furthermore, a cross bar is fixed on the vertical back plate, and springs are provided on both sides of the slide rail, one end of the spring is fixed on the cross bar, and the other end is fixed to the bottom of the slider. The spring is used to pull down the slide rail when no external force is applied, and the distance between the vertical push plates on both sides in this state is at the maximum distance, and the distance is greater than the width of the active head.

[0012] Furthermore, a limiting block fixed on the vertical back plate is provided on the top of the slide rail.

[0013] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0014] The use of a centering mechanism to force the steel support pipe to be placed in the center reduces the offset problem caused by traditional lifting relying on manual visual inspection, significantly reduces the stress concentration in the welds or bolt connections of the steel bracket, and solves the hidden danger of eccentric force of traditional steel supports. It is safe, efficient and economical, and provides reliable support and protection for large-span deep foundation pit projects. The centering can be completed by operating the pull rope on the ground, reducing the risk of high-altitude adjustment operations. Modular components, detachable steel brackets, and standard steel support pipes can be quickly installed and reused, shortening the construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a partial schematic diagram of an assembled steel support structure for excavation of a large-span deep foundation pit at an airport in an embodiment of the present application;

[0016] Figure 2 Schematic diagram of the structure between the steel purlin, steel bracket, steel support pipe, movable head and centering mechanism in the embodiment of the present application;

[0017] Figure 3 for Figure 2 Schematic diagram of the middle part structure;

[0018] Figure 4 for Figure 3 Schematic diagram of the middle part structure;

[0019] Figure 5 for Figure 4 Schematic diagram of the back;

[0020] In the figure: 1. Steel purlin; 2. Steel bracket; 3. Steel support tube; 4. Active head; 5. Centering mechanism; 21. Vertical back plate; 22. Horizontal support plate; 23. Triangular plate; 51. Side push assembly; 52. Upper pull assembly; 511. Vertical push plate; 512. Adapter block; 513. Connecting rod group; 211. Square hole; 5131. Connecting rod one; 5132. Connecting rod two; 5133. Connecting rod three; 514. Connecting rod; 5111. Hinge slot; 521. Slide rail; 522. Slider; 523. Pull rod; 524. Pull rope; 525. Cross bar; 526. Spring; 527. Limit block; 6. Support frame. DETAILED DESCRIPTION

[0021] In order to better understand the technical solution of the present application, the technical solution of the present application will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0022] Reference Figure 1 and Figure 2 The prefabricated steel support structure for excavation of large-span deep foundation pits at airports is mainly used for the support engineering of large-span deep foundation pits in the construction of airport tunnels. The prefabricated steel support structure includes a steel purlin 1, a steel bracket 2, a steel support pipe 3, a flexible head 4, a centering mechanism 5, and a support frame 6. Each steel bracket 2 is installed with a centering mechanism 5. Steel purlins 1 are constructed on the side walls on both sides of the length direction of the tunnel foundation pit. The steel purlins 1 are usually made of H-shaped steel or composite steel, and are fixed to the supporting piles or underground continuous walls by anchor rods or welding. Several steel brackets 2 are detachably connected along the length direction of the steel purlin 1 according to design requirements. The steel support pipe 3 is spliced ​​by multiple steel pipes according to design requirements. Flexible heads 4 are installed at both ends of the steel support pipe 3, and the flexible heads 4 are placed on the steel bracket 2. The support frame 6 is placed in the pit foundation. The support frame 6 is used to support the steel support pipe 3. The support frame 6 adopts a socket-type disc-type steel pipe bracket.

[0023] Reference Figure 2 and Figure 3 The steel bracket 2 is mainly composed of a vertical back plate 21, a horizontal bracing plate 22, and a triangular plate 23. The vertical back plate 21 is set vertically and connected to the steel purlin 1 by welding or bolts. The horizontal bracing plate 22 is perpendicular to the bottom edge of the vertical back plate 21. The top of the vertical back plate 21 needs to extend above the steel purlin 1 to a certain height, which can be 300-500mm, to facilitate the installation of the pull-up assembly 52 in the centering mechanism 5. The horizontal bracing plate 22 is used to support the movable head 4. Its width is greater than the width of the movable head 4 to ensure stable support.

[0024] Reference Figure 4 and Figure 5The centering mechanism 5 is mounted on the vertical back plate 21. It is used to center the steel support tube 3 on the steel bracket 2. The centering mechanism 5 includes two symmetrically arranged side push assemblies 51 and a set of pull-up assemblies 52. The two sets of side push assemblies 51 are symmetrically arranged on the side wall of the vertical back plate 21 facing the steel support tube 3. The side push assemblies 51 include a vertical push plate 511, an adapter block 512, a connecting rod assembly 513, and a connecting rod 514. The vertical push plate 511 is vertically arranged above the horizontal support plate 22, and the vertical push plate 511 is used to contact the side of the active head 4; the adapter block 512 is fixedly connected to the side wall of the vertical back plate 21 that contacts the active head 4, and the adapter block 512 is close to the side of the vertical back plate 21, and adapter blocks 512 are correspondingly provided at both ends of the vertical push plate 511; connecting rod groups 513 are provided between the two ends of the vertical push plate 511 and the two adapter blocks 512, and the two groups of connecting rod groups 513 are used to push the vertical push plate 511 horizontally.

[0025] Reference Figure 4 A hinge groove 5111 is provided in the middle of the side wall near the end of the vertical push plate 511. The connecting rod group 513 includes connecting rod 1 5131, connecting rod 2 5132, and connecting rod 3 5133. One end of connecting rod 1 5131 is hinged to the adapter block 512, and the other end faces the vertical push plate 511; one end of connecting rod 2 5132 is hinged to the end of connecting rod 1 5131 away from the adapter block 512, and the other end faces the vertical push plate 511; one end of connecting rod 3 5133 is hinged to the end of connecting rod 2 5132 away from connecting rod 2 5132, and the other end is hinged to the vertical push plate 511 and hinged in the hinge groove 5111 of the vertical push plate 511. Connecting rod 3 5133 and connecting rod 1 5131 are always parallel. Among them, the connecting rod 514 in each group of the side push assembly 51 is hinged between connecting rod 2 5132 in the upper and lower connecting rod groups 513.

[0026] Reference Figure 4 and Figure 5The pull-up assembly 52 includes a slide rail 521, a slider 522, a pull rod 523, a pull rope 524, a cross bar 525, a spring 526, and a limit block 527. The slide rail 521 is fixed to the middle of the side wall of the vertical back plate 21; the slider 522 is slidably connected to the slide rail 521; two pull rods 523 are provided and symmetrically arranged on both sides of the slider 522. The two pull rods 523 are respectively connected to the vertical push plates 511 of the side push assemblies 51 on both sides. One end of the pull rod 523 is hinged to the slider 522, and the other end is hinged to the vertical push plate 511. The vertical back plate 21 is provided with a square hole 211 at the top position of the vertical push plate 511. The hinge axis between the vertical push plate 511 and the pull rod 523 passes through the square hole 211; one end of the pull rope 524 is fixed to the slider 522, and the other end is used by the assembler standing on the ground to pull up. A crossbar 525 is fixed to the vertical back plate 21. The crossbar 525 is located at the bottom of the slide rail 521, with its two ends positioned on either side of the slide rail 521. Two springs 526 are provided, one on each side of the slide rail 521, with one end fixed to the crossbar 525 and the other to the bottom of the slider 522. When not under the action of an external force, the springs 526 pull down the slide rail 521. In this state, the distance between the two vertical push plates 511 is at its maximum, and this distance is greater than the width of the movable head 4. A stop block 527 is fixed to the top of the slide rail 521 and is fixedly connected to the vertical back plate 21.

[0027] Before installing the steel bracket 2, the centering mechanism 5 needs to be pre-debugged to ensure smooth movement of the vertical push plate 511 without any jamming. Check whether the elasticity of the spring 526 is normal to avoid failure of the spring 526 to cause the vertical push plate 511 to be unable to reset.

[0028] This application can explain its functional principles through the following operation methods:

[0029] Initial hoisting: Use a crane to lift the steel support pipe 3 into the foundation pit, with both ends aligned with the steel brackets 2 on both sides. Due to the heavy weight of the steel support pipe 3, it needs to be lowered slowly during hoisting to avoid impacting the steel bracket 2.

[0030] Place the steel support tube 3: Initially place the movable heads 4 at both ends of the steel support tube 3 on the horizontal support plate 22. At this time, due to the action of the spring 526, the vertical push plates 511 on both sides are in an outward expansion state, and the movable heads 4 can smoothly enter the space between the vertical push plates 511 on both sides.

[0031] Centering adjustment: The construction personnel pull the pull rope 524 to move the slider 522 upward along the slide rail 521, driving the pull rod 523 to retract inward. The pull rod 523 is connected to the vertical push plate 511 through the square hole 211, thereby pushing the vertical push plates 511 on both sides to move synchronously toward the middle. The vertical push plates 511 are pushed smoothly through the connecting rod group 513 to ensure that the active head 4 is evenly pushed to the center position of the steel bracket 2. When the active head 4 is completely centered, stop pulling the pull rope 524. At this time, the steel support pipe 3 is in the center position.

[0032] Locking and inspection: Check whether the steel support tube 3 is completely centered. If necessary, fine-tune the pull rope 524 to ensure accurate positioning.

[0033] In this way, the centering mechanism 5 is used to force the steel support pipe 3 to be placed in the center, reducing the offset problem caused by traditional lifting relying on manual visual inspection, significantly reducing the stress concentration in the welds or bolt connections of the steel bracket 2, preventing local cracking or deformation, and improving the overall stability of the support system. In addition, centering can be completed by operating the pull rope 524 on the ground, reducing the risk of high-altitude adjustment operations, modular components, detachable steel brackets 2, and standard steel support pipes 3 to achieve rapid installation and reuse, shortening the construction period.

[0034] This application solves the hidden danger of eccentric stress of traditional steel supports through mechanical centering adjustment and modular design, and combines safety, efficiency and economy, providing reliable support for large-span deep foundation pit projects.

[0035] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

[0036] The above is only a preferred specific implementation method of the embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solution and concept of the present application within the technical scope disclosed in the present application, and they should be covered by the scope of protection of the present application.

Claims

1. An assembled steel support structure for earthwork excavation of a large-span deep foundation pit of an airport, comprising a steel purlin (1) constructed on the side wall of the foundation pit, a steel bracket (2) fixed on the steel purlin (1), a steel support pipe (3) placed on the steel bracket (2), a movable head (4) installed on the end of the steel support pipe (3), and a support frame (6) for supporting the steel support pipe (3), wherein the movable head (4) abuts against the steel bracket (2), and the steel bracket (2) comprises a vertical back plate (21) fixed on the steel purlin (1) and a horizontal support plate (22) perpendicular to the vertical back plate (21), characterized in that: A centering mechanism (5) is installed on the vertical back plate (21), and the centering mechanism (5) is used to center the steel support tube (3) on the steel bracket (2), and the top edge of the vertical back plate (21) extends above the steel purlin (1); The centering mechanism (5) comprises: Two sets of side-pushing components (51) are provided and symmetrically mounted on both sides of the vertical back plate (21), and the movable head (4) is located between the side-pushing components (51) on both sides; The upper pull component (52) is arranged in the middle position between the side push components (51) on both sides and is installed on a side wall of the vertical back plate (21) away from the movable head (4), and the fixed position of the upper pull component (52) is located at a position where the vertical back plate (21) extends above the steel purlin (1). The upper pull component (52) is used to synchronize the side push components (51) on both sides to move closer to or away from each other.

2. The assembled steel support structure for earthwork excavation of a large-span deep foundation pit at an airport as claimed in claim 1, characterized in that: The side push assembly (51) comprises: A vertical push plate (511) is vertically arranged above the horizontal support plate (22) and is used to abut against the movable head (4); The adapter block (512) is fixedly connected to the side wall of the vertical back plate (21) that contacts the movable head (4) and is close to the side of the vertical back plate (21). The adapter block (512) is correspondingly provided at both ends of the vertical push plate (511); Connecting rod groups (513), connecting rod groups (513) are provided between the two ends of the vertical push plate (511) and the two adapter blocks (512), and the two connecting rod groups (513) are used to push the vertical push plate (511) laterally; The vertical back plate (21) is provided with a square hole (211) at the top of the vertical push plate (511), and the upper pull assembly (52) is connected to the vertical push plate (511) through the square hole (211).

3. The assembled steel support structure for earthwork excavation of a large-span deep foundation pit at an airport as claimed in claim 2, characterized in that: The connecting rod assembly (513) includes: Connecting rod 1 (5131), one end of which is hinged to the adapter block (512), and the other end of which faces the vertical push plate (511); Connecting rod 2 (5132), one end of which is hinged to the end of connecting rod 1 (5131) away from the adapter block (512), and the other end of which faces the vertical push plate (511); One end of the connecting rod three (5133) is hinged to the end of the connecting rod two (5132) away from the connecting rod two (5132), and the other end is hinged to the vertical push plate (511). The connecting rod three (5133) is always parallel to the connecting rod one (5131).

4. The assembled steel support structure for earthwork excavation of a large-span deep foundation pit at an airport as claimed in claim 3, characterized in that: A connecting rod (514) is hinged between the second connecting rod (5132) in the two connecting rod groups (513) at both ends of the vertical push plate (511).

5. The assembled steel support structure for earthwork excavation of a large-span deep foundation pit at an airport as claimed in claim 3, characterized in that: A hinge groove (5111) is provided in the middle of the side wall of the vertical push plate (511) near the end, and the connecting rod three (5133) is hinged in the hinge groove (5111).

6. The assembled steel support structure for earthwork excavation of a large-span deep foundation pit at an airport as claimed in claim 2, characterized in that: The pull-up assembly (52) comprises: A slide rail (521) is fixed to the middle portion of the side wall of the vertical back plate (21); A slider (522) is slidably connected to the slide rail (521); Two pull rods (523) are provided and symmetrically arranged on both sides of the slider (522), and the two pull rods (523) are respectively connected to the vertical push plates (511) of the side push assemblies (51) on both sides. One end of the pull rod (523) is hinged to the slider (522), and the other end is hinged to the vertical push plate (511), and the hinge axis between the vertical push plate (511) and the pull rod (523) passes through the square hole (211) of the vertical back plate (21); A pull rope (524) has one end fixed to the slider (522) and the other end used for assembling personnel to pull upward.

7. The assembled steel support structure for earthwork excavation of a large-span deep foundation pit at an airport as claimed in claim 6, characterized in that: A cross bar (525) is also fixed to the vertical back plate (21), and springs (526) are provided on both sides of the slide rail (521). One end of the spring (526) is fixed to the cross bar (525), and the other end is fixed to the bottom of the slider (522). The spring (526) is used to pull down the slide rail (521) when no external force is applied, and the distance between the vertical push plates (511) on both sides in this state is at a maximum distance, and the distance is greater than the width of the movable head (4).

8. The assembled steel support structure for earthwork excavation of a large-span deep foundation pit at an airport as claimed in claim 6, characterized in that: A limiting block (527) fixed on the vertical back plate (21) is provided on the top of the slide rail (521).

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