Prestressed steel support structure for fish-bellied foundation pit

Abstract

This application relates to the technical field of foundation pit support, and in particular to a prestressed fish-belly type steel support structure for foundation pits, which includes a prestressed fish-belly beam. Both ends of the upper chord of the prestressed fish-belly beam are equipped with loading devices for tensioning steel strands. The loading device includes a loading drive and a winding drum. The output shaft of the loading drive is coaxially fixed to the winding drum. The end of the steel strand passes through the winding drum and is connected to a locking pin, which abuts against the circumferential sidewall of the winding drum. The winding drum is used to wind the steel strand. Both ends of the upper chord of the prestressed fish-belly beam are also equipped with locking devices for clamping the steel strands. This application has the effect of facilitating the adjustment of the tension of the steel strands, ensuring construction progress, and improving construction efficiency.

Description

Technical Field

[0001] This application relates to the technical field of foundation pit support, and in particular to prestressed fish-belly type steel support structure for foundation pits. Background Technology

[0002] The prestressed fish-belly type foundation pit steel support structure system mainly consists of horizontal support structures and vertical support structures. The horizontal support structure mainly includes bracing, corner bracing, prestressed fish-belly beams, lintel beams, and connecting rods; the vertical support structure mainly includes columns (piles) and connectors. Bracing is generally parallel to the short side of the foundation pit to support the long side continuous wall; corner bracing is located at the corners of the foundation pit to support the corners; prestressed fish-belly beams are located between the bracing and corner bracing to support the continuous wall; lintel beams connect the bracing and the prestressed fish-belly beams; and connecting rods connect the various components; the columns (piles) support the bracing and the prestressed fish-belly beams.

[0003] The prestressed fish-belly beam mainly consists of a top chord (steel waler), steel strands, web members, and triangular keys. The triangular keys are located at both ends of the top chord (steel waler) and contain anchorages to secure the top chord (steel waler) to the diaphragm wall of the foundation pit. The web members are fixedly connected to the top chord (steel waler) and are perpendicular to the top chord (steel waler) and horizontally positioned. The ends of the steel strands are connected to two sets of triangular keys to tighten each web member. The prestressed fish-belly beam is a special truss structure where the top chord (steel waler) and web members are primarily under compression, while the steel strands are only under tension.

[0004] Compared to traditional support systems, prestressed fish-belly steel structure supports apply sufficient prestress before excavation, eliminating most of the compressive deformation and thus improving the safety of the foundation pit support structure and reducing the deformation of the foundation pit. During the excavation process, the prestressed fish-belly steel structure support can adjust the prestress through loading devices to ensure the safety of the support structure and control the deformation of the surrounding soil, effectively protecting the safety of buildings, municipal roads, pipelines, and other objects around the foundation pit from potential large water and soil pressures or sudden construction loads. To achieve effective monitoring of water and soil pressure on the foundation pit sidewalls and deformation of the retaining structure, a multi-functional monitoring and alarm system is used, thereby essentially eliminating the safety risks of the foundation pit support structure.

[0005] Regarding the aforementioned technologies, the inventors believe that the following drawbacks exist: adjusting the tension of the steel strand requires the assistance of an external loading device. During the excavation of the foundation pit, the tension of the steel strand still needs to be continuously adjusted according to the deformation of the foundation pit. However, the external loading device is large in size, heavy in weight, and inconvenient to move, making it difficult for the external loading device to adjust the tension of the steel strand, thus delaying the construction progress and reducing construction efficiency. Summary of the Invention

[0006] To facilitate tension adjustment of the steel strands, ensure construction progress, and improve construction efficiency, this application provides a prestressed fish-belly type steel support structure for foundation pits.

[0007] The prestressed fish-belly type foundation pit steel support structure adopts the following technical solution:

[0008] A prestressed fish-belly type foundation pit steel support structure includes a prestressed fish-belly beam. Both ends of the upper chord of the prestressed fish-belly beam are equipped with loading devices for tensioning steel strands. Each loading device includes a loading drive and a winding drum. The output shaft of the loading drive is coaxially fixed to the winding drum. The end of the steel strand passes through the winding drum and is connected to a locking pin, which abuts against the circumferential sidewall of the winding drum. The winding drum is used to wind the steel strand. Both ends of the upper chord of the prestressed fish-belly beam are also equipped with locking devices for securing the steel strands.

[0009] By adopting the above technical solution, during the excavation of the foundation pit, the tension of the steel strand needs to be continuously adjusted according to the deformation of the pit. First, the locking device is unlocked, releasing its clamping force on the steel strand, allowing the loading device to tension it. Then, the loading drive is activated, causing the winding drum to slowly rotate and wind or release the steel strand, achieving automatic and rapid adjustment of the steel strand tension. After adjustment, the locking device is used again to tighten the steel strand, maintaining a stable taut state. The loading device, in conjunction with the locking device, facilitates the adjustment of the steel strand tension, ensuring construction progress and improving construction efficiency.

[0010] Optionally, the inside of the winding drum is hollow.

[0011] By adopting the above technical solution, the inside of the winding drum is made hollow, which can reduce the weight of the winding drum, thereby reducing the weight of the prestressed fish-belly beam and maintaining the good service form of the prestressed fish-belly beam.

[0012] Optionally, the end of the straight web bar away from the upper chord is hinged to an arc-shaped spool, through which the steel strand passes and slides in cooperation with the arc-shaped spool.

[0013] By adopting the above technical solution, during the process of the steel strand being tightened, the relative position of the steel strand and the straight web bar changes slightly, and the angle also changes slightly. The arc-shaped bobbin can not only make the steel strand be tightened smoothly, but also adapt to the angle change between the steel strand and the straight web bar.

[0014] Optionally, the inner wall of the arc-shaped spool is fitted with rolling balls, which roll in cooperation with the steel strand.

[0015] By adopting the above technical solution, the ball bearings can reduce the friction between the steel strand and the inner wall of the curved drum, allowing the steel strand to move more smoothly inside the curved drum.

[0016] Optionally, the arc-shaped spool has an oil injection hole that penetrates the side wall of the arc-shaped spool.

[0017] By adopting the above technical solution, after adding lubricating oil to the inside of the arc-shaped drum through the oil injection hole, the friction between the steel strand and the inner wall of the arc-shaped drum can be reduced, allowing the steel strand to move more smoothly inside the arc-shaped drum, reducing the wear of the steel strand, and extending the service life of the steel strand and the arc-shaped drum.

[0018] Optionally, the wire locking device includes a dynamic pressure pad, a static pressure pad, and a wire locking drive. The steel strand is located between the dynamic pressure pad and the static pressure pad. The static pressure pad is fixedly connected to the beam of the triangular key. The wire locking drive is fixedly connected to the side wall of the upper chord. The dynamic pressure pad is fixedly connected to the piston rod of the wire locking drive. The concave surfaces of the dynamic pressure pad and the static pressure pad that face each other can jointly press against the steel strand.

[0019] By adopting the above technical solution, when locking the steel strand, the locking drive component moves the moving pressure plate closer to the static pressure plate. The moving and static pressure plates work together to press the steel strand, achieving automatic and rapid clamping and fixing of the steel strand, and ensuring stable clamping. When it is necessary to adjust the tension of the steel strand, the locking drive component reverses its movement, moving the moving pressure plate away from the static pressure plate, releasing the pressure on the steel strand. The tension of the steel strand can then be adjusted by the loading device. The entire locking and releasing process can be carried out automatically and quickly.

[0020] Optionally, the dynamic pressure tile and the static pressure tile are each fixed with a wing plate on their mutually distant sides, and the two corresponding wing plates are jointly fitted with fastening bolts.

[0021] By adopting the above technical solution, the fastening bolts connect the dynamic pressure plate and the static pressure plate into one unit through the wing plate. The dynamic pressure plate and the static pressure plate can jointly form a ring to clamp the steel strand, further improving the stability of the dynamic pressure plate and the static pressure plate clamping the steel strand, and further improving the locking effect of the wire locking device on the steel strand.

[0022] Optionally, the concave surfaces of both the dynamic and static pressure tiles are provided with anti-slip ridges.

[0023] By adopting the above technical solution, the anti-slip embossing can increase the contact static friction between the dynamic pressure tile, the static pressure tile and the steel strand, and improve the clamping stability of the dynamic pressure tile and the static pressure tile for the steel strand.

[0024] In summary, this application includes at least one of the following beneficial technical effects:

[0025] 1. During the excavation of the foundation pit, the loading device can easily realize the automatic and rapid adjustment of the tension of the steel strand, ensuring the construction progress and improving the construction efficiency;

[0026] 2. The wire locking device can clamp the steel strand, keep the steel strand in a stable tension state, reduce the load of the loading device, and improve the supporting stability of the prestressed fish belly beam for the foundation pit continuous wall;

[0027] 3. The arc-shaped wire cylinder can not only smoothly tighten the steel strand, but also adapt to the angle change between the steel strand and the straight web member. Description of the Drawings

[0028] Figure 1 is a schematic structural diagram of the prestressed fish belly type foundation pit steel support structure of the embodiment of the present application;

[0029] Figure 2 is a schematic structural diagram showing the anti-slip convex pattern;

[0030] Figure 3 is a cross-sectional view showing the ball.

[0031] Description of the reference numerals: 1, prestressed fish belly beam; 11, upper chord; 111, loading support plate; 112, wire locking support plate; 12, straight web member; 121, arc-shaped wire cylinder; 122, ball; 123, oil injection hole; 13, triangular key; 131, support rod; 14, steel strand; 141, set screw; 2, loading device; 21, loading drive member; 22, wire winding cylinder; 3, wire locking device; 31, dynamic pressure tile; 32, static pressure tile; 33, wire locking drive member; 4, wing plate; 5, fastening bolt; 6, anti-slip convex pattern. Detailed Embodiment

[0032] The following will further elaborate on the present application in conjunction with the attached Figure 1-3 drawings.

[0033] The embodiment of the present application discloses a prestressed fish belly type foundation pit steel support structure, referring to Figure 1 and Figure 2 [[ID=X]] [[ID=Y]]

[0034] The prestressed fish belly type foundation pit steel support structure includes a prestressed fish belly beam 1. The upper chord 11, triangular key 13 and straight web member 12 of the prestressed fish belly beam 1 are all made of I-beams. Loading devices 2 and wire locking devices 3 are fixedly arranged at both ends of the upper chord 11 of the prestressed fish belly beam 1; both the loading device 2 and the wire locking device 3 are located in the internal space surrounded by the triangular key 13, and the loading device 2 is located between the end of the upper chord 11 and the wire locking device 3. An arc-shaped wire cylinder 121 is hinged at the end of each straight web member 12 far from the upper chord 11. The hinge axis of the arc-shaped wire cylinder 121 is vertical, and the steel strand 14 passes through each arc-shaped wire cylinder 121 and is in sliding fit with the arc-shaped wire cylinder 121.

[0034] During the excavation of the foundation pit, the tension of the steel strand 14 needs to be continuously adjusted according to the deformation of the pit. First, the locking device 3 is unlocked, releasing its clamping force on the steel strand 14, allowing the loading device 2 to tension it. Subsequently, the loading device 2 is used to automatically and quickly adjust the tension of the steel strand 14. During the tensioning process, the relative position and angle between the steel strand 14 and the straight web bar 12 change slightly. The curved bobbin 121 can both smoothly tension the steel strand 14 and accommodate the angle changes between the steel strand 14 and the straight web bar 12. After adjustment, the locking device 3 is used to tighten the steel strand 14 again, maintaining a stable tension. The loading device 2, in conjunction with the locking device 3, facilitates the tension adjustment of the steel strand 14, ensuring construction progress and improving construction efficiency.

[0035] Reference Figure 1 and Figure 2 The wire locking device 3 includes a dynamic pressure plate 31, a static pressure plate 32, and a wire locking drive 33. A support rod 131 is fixedly connected to the flange 4 of the I-beam forming the triangular key 13 on the side facing away from the straight web member 12. The support rod 131 is fixedly connected to the static pressure plate 32 on the side facing the upper chord member 11. A horizontal wire locking support plate 112 is fixedly connected to the flange 4 of the I-beam forming the upper chord member 11 in the beam segment located inside the triangular key 13. The top surface of the wire locking support plate 112 is fixedly connected to the wire locking drive 33. In this embodiment, the wire locking drive 33 is a hydraulic cylinder. The dynamic pressure plate 31 is fixedly connected to the piston rod of the wire locking drive 33. The steel strand 14 is located between the dynamic pressure plate 31 and the static pressure plate 32. The concave surfaces of the dynamic pressure plate 31 and the static pressure plate 32, which face each other, can jointly press against the steel strand 14. The concave surfaces of both the dynamic pressure tile 31 and the static pressure tile 32 are integrally formed with multiple evenly distributed anti-slip ridges 6, which form an angle with the axes of the dynamic pressure tile 31 and the static pressure tile 32. The mutually distant sides of both the dynamic pressure tile 31 and the static pressure tile 32 are integrally formed with wing plates 4, and two corresponding wing plates 4 are connected by fastening bolts 5, which fix the dynamic pressure tile 31 and the static pressure tile 32 to compress the steel strand 14.

[0036] When locking the steel strand 14, the locking drive component 33 drives the moving pressure plate 31 to gradually approach the static pressure plate 32. The moving pressure plate 31 and the static pressure plate 32 together press the steel strand 14, realizing automatic and rapid clamping and fixing of the steel strand 14, and ensuring stable clamping of the steel strand 14. Tightening the fastening bolt 5 connects the moving pressure plate 31 and the static pressure plate 32 into one unit through the wing plate 4. The moving pressure plate 31 and the static pressure plate 32 can together form a ring to clamp the steel strand 14. The anti-slip ridges 6 can increase the contact static friction between the moving pressure plate 31, the static pressure plate 32 and the steel strand 14, and improve the clamping stability of the moving pressure plate 31 and the static pressure plate 32 for the steel strand 14. When it is necessary to adjust the tension of the steel strand 14, the fastening bolt 5 is removed, causing the locking drive 33 to move in the opposite direction. The locking drive 33 drives the moving pressure plate 31 away from the static pressure plate 32, releasing the pressure on the steel strand 14, so that the tension of the steel strand 14 can be adjusted by the loading device 2.

[0037] Reference Figure 1 and Figure 2 The loading device 2 includes a loading drive 21 and a winding drum 22. A horizontal loading support plate 111 is fixedly connected to the flange 4 of the I-beam forming the upper chord 11 within the beam segment located inside the triangular key 13. The top surface of the loading support plate 111 is fixedly connected to the loading drive 21. In this embodiment, the loading drive 21 is a high-power servo motor. The output shaft of the loading drive 21 is coaxially fixedly connected to the winding drum 22. The end of the steel strand 14 passes through the I-beam of the triangular key 13 and the winding drum 22 and is fixedly connected to a locking pin 141. The locking pin 141 abuts against the circumferential sidewall of the winding drum 22, which is hollow inside.

[0038] The loading drive 21 is activated, which drives the winding drum 22 to rotate slowly and wind or release the steel strand 14, thereby achieving automatic and rapid adjustment of the tension of the steel strand 14. The interior of the winding drum 22 is hollow, which reduces its own weight, thereby reducing the weight of the prestressed fish-belly beam 1 and maintaining its good working form.

[0039] Reference Figure 1 and Figure 3 The inner wall of the arc-shaped wire drum 121 is fitted with multiple sets of ball bearings 122. Each set of ball bearings 122 includes multiple balls 122, and all the balls 122 in each set are evenly distributed circumferentially about the axis of the arc-shaped wire drum 121. The balls 122 are in rolling contact with the steel strand 14. The arc-shaped wire drum 121 has multiple oil injection holes 123 that penetrate the side wall of the arc-shaped wire drum 121.

[0040] The ball bearing 122 reduces the friction between the steel strand 14 and the inner wall of the curved drum 121, allowing the steel strand 14 to move more smoothly inside the curved drum 121. Adding lubricating oil to the inside of the curved drum 121 through the oil injection hole 123 further reduces the friction between the steel strand 14 and the inner wall of the curved drum 121, as well as the ball bearing 122, allowing the steel strand 14 to move more smoothly inside the curved drum 121, reducing wear on the steel strand 14, and extending the service life of both the steel strand 14 and the curved drum 121.

[0041] The implementation principle of the prestressed fish-belly type foundation pit steel support structure in this application embodiment is as follows:

[0042] During the excavation of the foundation pit, the tension of the steel strand 14 needs to be continuously adjusted according to the deformation of the foundation pit.

[0043] First, unlock the wire locking device 3, remove the fastening bolt 5, and activate the wire locking drive 33. The wire locking drive 33 drives the moving pressure plate 31 away from the static pressure plate 32, releasing the pressure on the steel strand 14. The tension of the steel strand 14 can then be adjusted by the loading device 2.

[0044] Subsequently, the loading drive 21 is activated, which drives the winding drum 22 to rotate slowly and wind or release the steel strand 14, thereby achieving automatic and rapid adjustment of the tension of the steel strand 14. During the process of the steel strand 14 being tightened, the relative position of the steel strand 14 and the straight web bar 12 changes slightly, and the angle also changes slightly. The arc-shaped drum 121 can not only smoothly tighten the steel strand 14, but also adapt to the angle change between the steel strand 14 and the straight web bar 12.

[0045] After adjustment, the locking drive 33 drives the moving pressure plate 31 to gradually approach the static pressure plate 32. The moving pressure plate 31 and the static pressure plate 32 together press the steel strand 14, achieving automatic and rapid clamping and fixing of the steel strand 14. Tighten the fastening bolt 5. The fastening bolt 5 connects the moving pressure plate 31 and the static pressure plate 32 into one unit through the wing plate 4. The moving pressure plate 31 and the static pressure plate 32 can together form a ring to tightly grip the steel strand 14, maintaining a stable tension state of the steel strand 14. The loading device 2, in conjunction with the locking device 3, facilitates the adjustment of the tension of the steel strand 14, ensuring construction progress and improving construction efficiency.

[0046] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A prestressed fish-belly type foundation pit steel support structure, comprising a prestressed fish-belly beam (1), characterized in that: The upper chord (11) of the prestressed fish belly beam (1) is provided with loading devices (2) at both ends for tightening the steel strand (14). The loading device (2) includes a loading drive (21) and a winding drum (22). The output shaft of the loading drive (21) is coaxially fixed to the winding drum (22). The end of the steel strand (14) passes through the winding drum (22) and is connected to a locking pin (141). The locking pin (141) abuts against the circumferential side wall of the winding drum (22). The winding drum (22) is used to wind the steel strand (14). The upper chord (11) of the prestressed fish belly beam (1) is also provided with locking devices (3) at both ends for clamping the steel strand (14). The loading device (2) and the locking device (3) are both located in the internal space enclosed by the triangular key (13). The locking device (3) includes a dynamic pressure plate (31), a static pressure plate (32), and a locking drive (33). The steel strand (14) is located between the dynamic pressure plate (31) and the static pressure plate (32). The static pressure plate (32) is fixed to the beam of the triangular key (13). The locking drive (33) is fixed to the side wall of the upper chord (11). The dynamic pressure plate (31) is fixed to the piston rod of the locking drive (33). The concave surfaces of the dynamic pressure plate (31) and the static pressure plate (32) facing each other can jointly press against the steel strand (14). The end of the straight bar (12) away from the upper chord bar (11) is hinged to an arc-shaped spool (121), and the steel strand (14) passes through the arc-shaped spool (121) and slides with the arc-shaped spool (121).

2. The prestressed fish-belly type foundation pit steel support structure according to claim 1, characterized in that: The inside of the winding drum (22) is hollow.

3. The prestressed fish-belly type foundation pit steel support structure according to claim 1, characterized in that: The inner wall of the arc-shaped spool (121) is fitted with rolling balls (122), which roll in cooperation with the steel strand (14).

4. The prestressed fish-belly type foundation pit steel support structure according to claim 1, characterized in that: The arc-shaped spool (121) has an oil injection hole (123) that penetrates the side wall of the arc-shaped spool (121).

5. The prestressed fish-belly type foundation pit steel support structure according to claim 1, characterized in that: The dynamic pressure tile (31) and the static pressure tile (32) are both fixed with wing plates (4) on their mutually distant sides, and the two corresponding wing plates (4) are connected by fastening bolts (5).

6. The prestressed fish-belly type foundation pit steel support structure according to claim 1, characterized in that: The inner concave surfaces of the dynamic pressure tile (31) and the static pressure tile (32) are both provided with anti-slip ridges (6).

Images