A sloping steel trestle bridge for soil extraction in large deep foundation pits and its construction method

Abstract

This application discloses an inclined steel trestle bridge for excavating soil from large deep foundation pits and its construction method, relating to the field of steel trestle bridges for deep foundation pit excavation. It includes a bottom support and a bridge deck system located above the bottom support. The bridge deck system includes a horizontal section at the top of the deep foundation pit and an inclined section extending into the bottom of the deep foundation pit. The inclined section includes several precast slabs connected in sequence. A sliding track for the precast slabs is provided at the top of the bottom support. Adjacent precast slabs are connected by connecting members. A driving component is provided on the horizontal section to drive the uppermost precast slab downwards along the sliding track. This application significantly reduces the difficulty of on-site construction and shortens the construction period.

Description

Technical Field

[0001] This invention relates to the field of steel trestle bridges for deep foundation pit excavation, and in particular to an inclined steel trestle bridge for large deep foundation pit excavation and its construction method. Background Technology

[0002] When constructing deep foundation pits for large-scale building projects, it is necessary to excavate and remove soil. Due to the depth of the foundation pit, the large number of internal supports, and the large area of ​​the foundation pit, excavators cannot cover the soil on the ground. In this case, it is necessary to slope the soil layer inside the deep foundation pit or use a sloping steel trestle to enter the lower internal support slab to remove soil.

[0003] The applicant found the following problems with conventional inclined steel trestle bridges:

[0004] The inclined steel trestle bridge is a transition channel from one inner support to the next. The height span between the top and bottom of the inclined steel trestle bridge is large. During construction, the construction materials are transported to the site and the construction is carried out by on-site welding, which is difficult and time-consuming.

[0005] Therefore, this application provides a sloping steel trestle bridge for large deep foundation pit soil extraction and its construction method, which reduces construction difficulty and shortens the construction period. Summary of the Invention

[0006] To reduce the difficulty of on-site construction and shorten the construction period, this application provides an inclined steel trestle bridge for soil extraction in large deep foundation pits and its construction method.

[0007] The technical solution provided in this application for a sloping steel trestle bridge for soil extraction in large deep foundation pits and its construction method is as follows:

[0008] A sloping steel trestle bridge for excavating soil from a large deep foundation pit includes a bottom support and a bridge deck system located above the bottom support. The bridge deck system includes a horizontal section located on the ground at the top of the deep foundation pit and an inclined section extending into the bottom of the deep foundation pit. The inclined section includes a plurality of precast slabs connected in sequence. The top of the bottom support is provided with a slide for the precast slabs to slide. Adjacent precast slabs are connected by connecting members. A driving member is provided on the ground at the top of the deep foundation pit to drive the uppermost precast slab to move downward along the slide.

[0009] By adopting the above technical solution, the bridge deck system is divided into several precast slabs. After the precast slabs are processed in the factory, they only need to be hoisted to the higher end of the inclined section of the bridge deck system on site. The precast slabs are then driven to slide down the slide rail by a drive component. When the sliding distance of the precast slab is greater than its own length, the output end of the drive component is controlled to retract, and another precast slab is placed. The above steps are repeated to drive all the precast slabs. They are then connected by connecting components to achieve assembly. This greatly reduces the construction difficulty on site, shortens the construction period, and provides an effective reference for subsequent similar projects.

[0010] Preferably, the bottom support includes a plurality of trestle piles, a pile top distribution beam disposed on top of the trestle piles, a Bailey beam disposed on top of the pile top distribution beam, and a plurality of I-beams disposed on top of the Bailey beams. The I-beams are arranged along the extension direction of the bridge deck system. Two I-beams located on both sides of the width direction of the bridge deck system are respectively provided with enclosures on their outer sides, and a sliding track for the precast slab to slide is formed between the two enclosures.

[0011] By adopting the above technical solution, by setting up barriers on the outside of the two I-beams, the two barriers and the I-beams together form a slide for the precast slab to slide, which limits the precast slab and prevents it from shifting to the left or right or even falling off during the sliding process.

[0012] Preferably, the precast slab includes a concrete slab, a precast steel plate, and a channel steel arranged from top to bottom. The channel steel extends along the width direction of the bridge deck system and is used for welding and fixing with the I-beams.

[0013] By adopting the above technical solution, channel steel is used to connect with the I-beams in the bottom support, precast steel plates are used to connect adjacent precast plates, and the setting of concrete slabs increases the friction between vehicles and the trestle when vehicles are walking, reducing the occurrence of vehicle slippage, thereby reducing wear on the trestle and extending the service life of the trestle.

[0014] Preferably, the connecting member is configured as a limiting component for restricting the relative movement of two adjacent precast slabs along the length direction of the slide.

[0015] By adopting the above technical solution, when the upper precast slab moves and is connected to the lower limiting plate through the connecting member, the upper limiting plate and the lower limiting plate can no longer be separated along the length of the slide.

[0016] Preferably, a first connecting groove and a second connecting groove are respectively provided on the two adjacent precast steel plates that are close to each other. The connecting member includes a wedge block that slides and is connected in the first connecting groove along the thickness direction of the precast steel plate. The wedge block is connected to the first connecting groove by a spring. A connecting plate and a limiting clip are fixed in the second connecting groove. The limiting clip is used to apply a force to the wedge surface of the wedge block to drive the wedge block to retract, so that the limiting clip abuts against the side wall of the wedge block through the wedge block.

[0017] By adopting the above technical solution, when the upper precast slab approaches the lower precast slab, the limiting clip applies force to the wedge surface of the wedge block. The wedge block retracts, allowing the limiting clip to pass through. After passing through the wedge block, the limiting clip abuts against the vertical surface of the wedge block. At this time, the two adjacent precast slabs abut against each other. The cooperation between the limiting clip and the wedge block restricts the movement of the two adjacent precast slabs in opposite directions, thereby realizing the connection between the two adjacent precast slabs.

[0018] Preferably, the bottom end of the bottom support is provided with a limiting plate for limiting the movement range of the precast slab located at the bottommost position.

[0019] By adopting the above technical solution, when the precast slab at the bottom moves to the predetermined position, the precast slab abuts against the limiting plate, restricting the further downward movement of the precast slab and facilitating the positioning of the precast slab.

[0020] Preferably, the limiting plate is provided with an airbag on the side facing the bridge deck system.

[0021] By adopting the above technical solution, the limiting plate is set as an airbag, which not only achieves the positioning of the precast slab, but also plays a buffering role when the precast slab collides with the limiting plate, reducing the possibility of damage to the precast slab due to the collision.

[0022] A construction method for an inclined steel trestle bridge used for soil extraction in large deep foundation pits includes the following steps:

[0023] S1. Construct the bottom support structure on site;

[0024] S2. On site, the precast slab is hoisted to the end with the higher bottom support and driven to slide down the slide rail by the drive component. When the sliding distance of the precast slab is greater than its own length, the output end of the drive component is controlled to retract and another precast slab is placed. The above steps are repeated to drive all the precast slabs. During the downward movement of the precast slabs, adjacent precast slabs are connected by connecting components.

[0025] Construct the horizontal section of the bridge deck system on the ground at the top of the deep foundation pit, and fix the uppermost precast slab to the horizontal section of the bridge deck system;

[0026] Secure all precast slabs to the bottom support;

[0027] S3. Remove the limit plate.

[0028] In summary, this application includes at least one of the following beneficial technical effects:

[0029] 1. It greatly reduced the difficulty of on-site construction and shortened the construction period, providing an effective reference for subsequent similar projects.

[0030] 2. When the upper precast slab moves and is connected to the lower limiting plate through the connecting member, the upper limiting plate and the lower limiting plate can no longer be separated along the length of the slide, thus realizing the connection and limiting between the two adjacent precast slabs. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the overall structure showing the relationship between the inclined steel trestle bridge and the internal support in the embodiment.

[0032] Figure 2 This is a partial structural diagram of the slide and the inclined section structure in the bridge deck system shown in the embodiment.

[0033] Figure 3 This is a side view showing the bottom support structure.

[0034] Figure 4 This is a partial structural diagram showing the precast slab structure.

[0035] Figure 5 This is a schematic diagram showing the structure of the connecting components.

[0036] Explanation of reference numerals in the attached figures:

[0037] 01. Internal support; 1. Trestle pile; 11. Drilled pile; 12. Steel pipe pile; 2. Distribution beam; 3. Bailey beam; 4. Channel steel; 41. Enclosure; 5. Slide rail; 6. Precast slab; 61. Concrete slab; 62. Precast steel plate; 621. First connecting groove; 622. Second connecting groove; 623. Receiving groove; 63. I-beam; 7. Connecting component; 71. Wedge block; 711. Wedge surface; 72. Spring; 73. Connecting plate; 74. Limiting clip; 8. Hydraulic cylinder; 9. Limiting plate; 91. Airbag. Detailed Implementation

[0038] The following is in conjunction with the appendix Figure 1-5 This application will be described in further detail.

[0039] This application discloses an inclined steel trestle bridge for soil extraction in large deep foundation pits, used to connect the top ground of the deep foundation pit with the bottom construction surface of the deep foundation pit after the inner support 01 is constructed. The inclined steel trestle bridge includes a bottom support supported at the bottom of the deep foundation pit and a bridge deck system located above the bottom support.

[0040] The bottom support includes several trestle piles 1, a pile top distribution beam 2 located on top of the trestle piles 1, a Bailey beam 3 located on top of the pile top distribution beam 2, and several channel steels 4 located on top of the Bailey beam 3. Enclosures 41 are respectively provided on the outer sides of the I-beams 63 located on both sides of the width direction of the bridge deck system. The two enclosures 41 and the I-beams 63 together form a sliding track 5 for the precast slabs 6 to slide. The trestle piles 1 include bored piles 11 extending into the bottom of the foundation pit and steel pipe piles 12 with their bottom ends extending into the bored piles 11. An inter-pile connection system is provided between adjacent trestle piles 1.

[0041] The bridge deck system consists of horizontal and inclined sections. The horizontal section is located on the ground at the top of the deep foundation pit, while the inclined section extends downwards at its bottom to the construction surface at the bottom of the deep foundation pit.

[0042] The inclined section includes several precast slabs 6 connected sequentially along the length of the slide 5. After the precast slabs 6 are prefabricated in the factory, they are transported to the site for assembly of the inclined section system of the bridge deck.

[0043] The precast slab 6 includes a concrete slab 61, a precast steel plate 62, and an I-beam 63 arranged from top to bottom. The I-beam 63 and the precast steel plate 62 are welded and fixed together, with the I-beam 63 located at the middle of the length of the precast steel plate 62. In this embodiment, cylindrical head studs are welded onto the precast steel plate 62 as shear studs, and C40 low-shrinkage concrete is poured onto the precast steel plate 62 to form the concrete slab 61, thereby fixing the concrete slab 61 to the precast steel plate 62.

[0044] A connecting member 7 is provided between any two adjacent precast slabs 6 to connect them, and two connecting members 7 are spaced apart along the width direction of the bridge deck system.

[0045] The two ends of adjacent precast slabs 6 that are close to each other are respectively provided with a first connecting groove 621 and a second connecting groove 622, and the first connecting groove 621 and the second connecting groove 622 are provided at intervals along the width direction of the bridge deck system.

[0046] The connecting member 7 includes a receiving groove 623 formed in the top wall of the first connecting groove 621. The receiving groove 623 is arranged along the thickness direction of the precast slab 6. A wedge block 71 is slidably connected in the receiving groove 623. A spring 72 is provided between the top of the wedge block 71 and the receiving groove 623. The spring 72 is used to apply an outward force to the wedge block 71, causing one end of the wedge block 71 to extend out of the receiving groove 623. The wedge-shaped surface 711 of the end of the wedge block 71 extending out of the receiving groove 623 is located on the side of the wedge block 71 facing the second connecting groove 622. The distance between the wedge-shaped surface 711 and the second connecting groove 622 gradually increases from top to bottom. A connecting plate 73 is fixed in the second connecting groove 622. A limit clamp 74 is fixed to the free end of the connecting plate 73.

[0047] When the upper precast slab 6 approaches the lower precast slab 6, the limiting clip 74 applies force to the wedge surface 711 of the wedge block 71, driving the wedge block 71 to retract and allow the limiting clip 74 to pass. After passing the wedge block 71, the limiting clip 74 abuts against the vertical surface of the wedge block 71. At this time, the two adjacent precast slabs 6 abut against each other, and the cooperation between the limiting clip 74 and the wedge block 71 restricts the two adjacent precast slabs 6 from moving in opposite directions, thus realizing the connection between the two adjacent precast slabs 6.

[0048] A support is installed on the ground at the top of the deep foundation pit. A hydraulic cylinder 8 is installed at an angle on the support. The angle of the hydraulic cylinder 8 is the same as the angle of the slide 5. The output end of the hydraulic cylinder 8 is used to abut against the side of the uppermost precast slab 6 to drive the precast slab 6 to move down along the slide 5.

[0049] To limit the movement range of the bottom precast slab 6, a limiting plate 9 is welded to one end of the Bailey beam 3 near the bottom of the deep foundation pit. The limiting plate 9 is set perpendicular to the bridge deck system, and an airbag 91 is provided on the side wall of the limiting plate 9 facing the bridge deck system to buffer the limiting plate 9.

[0050] A construction method for an inclined steel trestle bridge used for soil extraction in large deep foundation pits includes the following steps:

[0051] S1. Bottom support construction:

[0052] Verify the location of trestle pile 1 based on the building structure pile location diagram and lay out the line. Construct trestle pile 1 and control the anchorage depth of steel pipe pile 12 to be no less than three meters.

[0053] Install pile caps to ensure the slope and smoothness of the pile head's beveled surface and to ensure the quality of the weld.

[0054] Install the pile top distribution beam 2 on the pile cap structure. The pile top distribution beam 2 and the pile cap structure must be tightly welded together to ensure the vertical load transfer.

[0055] Install Bailey beam 3 and lock it.

[0056] S2. Bridge deck system installation:

[0057] The precast slabs 6 are hoisted from the construction site by a crane to the higher end of the slide rail 5. The railings on both sides of the slide rail 5 restrict the left and right sliding of the precast slabs 6. The precast slabs 6 are driven to slide down the slide rail 5 by a hydraulic cylinder 8. When the sliding distance of the precast slabs 6 is greater than its own length, the output end of the hydraulic cylinder 8 is controlled to retract, and another precast slab 6 is hoisted. The above steps are repeated to drive all the precast slabs 6. During the downward movement of the precast slabs 6, adjacent precast slabs 6 are connected by connecting components.

[0058] Weld and fix all the I-beams 63 in the precast slabs 6 to the channel steel 4 in the bottom support;

[0059] Remove the supports and hydraulic cylinder 8, build the horizontal section of the bridge deck system on the ground at the top of the deep foundation pit, and weld and fix the uppermost precast slab 6 to the horizontal section of the bridge deck system.

[0060] S3. Install guardrails on both sides of the bridge deck system;

[0061] S4. Remove the limit plate 9 to allow vehicles to pass normally on the bridge surface system.

[0062] S5. Tractor load test and trestle acceptance.

[0063] This application discloses a construction method for a sloping steel trestle bridge used for soil extraction in large deep foundation pits. By disassembling the bridge deck system into several prefabricated slabs 6, the bridge deck system can be installed simply by assembling it on the construction site. This replaces the traditional method of completely assembling on-site, greatly reducing the difficulty of on-site construction and shortening the construction cycle, and providing an effective reference for subsequent similar projects.

[0064] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A sloping steel trestle bridge for excavating soil from large deep foundation pits, characterized in that: The bridge deck system includes a bottom support and a bridge deck system located above the bottom support. The bridge deck system includes a horizontal section located on the ground at the top of the deep foundation pit and an inclined section extending into the bottom of the deep foundation pit. The inclined section includes a number of precast slabs (6) connected in sequence. The top of the bottom support is provided with a slide rail (5) for the precast slabs (6) to slide. Adjacent precast slabs (6) are connected by a connecting member (7). The ground at the top of the deep foundation pit is provided with a driving member for driving the uppermost precast slab (6) to move downward along the slide rail (5). The bottom support includes several trestle piles (1), a pile top distribution beam (2) set on top of the trestle piles (1), a Bailey beam (3) set on top of the pile top distribution beam (2), and several channel steels (4) set on top of the Bailey beam (3). The channel steels (4) are set along the extension direction of the bridge deck system. The two channel steels (4) located on both sides of the width direction of the bridge deck system are respectively provided with enclosures (41). A slide (5) for sliding the precast slab (6) is formed between the two enclosures (41). The precast slab (6) includes a concrete slab (61), a precast steel plate (62), and an I-beam (63) arranged from top to bottom. The I-beam (63) extends along the width direction of the bridge deck system, and the precast steel plate (62) is used to weld and fix to the I-beam (63).

2. The inclined steel trestle bridge for excavation in large deep foundation pits according to claim 1, characterized in that: The connecting member (7) is configured as a limiting component to restrict the relative movement of two adjacent precast slabs (6) along the length direction of the slide (5).

3. A sloping steel trestle bridge for excavating soil from large deep foundation pits according to claim 1, characterized in that: Two adjacent precast steel plates (62) are provided with a first connecting groove (621) and a second connecting groove (622) on their respective sides. The connecting member (7) includes a wedge block (71) that slides along the thickness direction of the precast steel plate (62) and is connected to the first connecting groove (621). The wedge block (71) is connected to the first connecting groove (621) by a spring (72). A connecting plate (73) and a limiting clip (74) are fixed in the second connecting groove (622). The limiting clip (74) is used to apply a force to the wedge surface (711) of the wedge block (71) to drive the wedge block (71) to retract, so that the limiting clip (74) abuts against the side wall of the wedge block (71) through the wedge block (71).

4. A sloping steel trestle bridge for excavating soil from large deep foundation pits according to claim 1, characterized in that: The bottom support is provided with a limiting plate (9) for limiting the movement range of the precast slab (6) located at the bottommost point.

5. A sloping steel trestle bridge for excavating soil from large deep foundation pits according to claim 4, characterized in that: The limiting plate (9) is provided with an airbag (91) on the side facing the bridge deck system.

6. A construction method for an inclined steel trestle bridge for excavation in large deep foundation pits according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Construct the bottom support structure on site; S2. On site, the precast slab (6) is hoisted to the end with a higher bottom support and driven to slide down the slide rail (5) by the drive component. When the sliding distance of the precast slab (6) is greater than its own length, the output end of the drive component is controlled to retract and another precast slab (6) is placed. The above steps are repeated to drive all the precast slabs (6). During the downward movement of the precast slabs (6), adjacent precast slabs (6) are connected by the connecting component (7). Build a horizontal section of the bridge deck system on the top ground of the deep foundation pit, and fix the uppermost precast slab (6) to the horizontal section of the bridge deck system; Secure all precast slabs (6) to the bottom support; S3. Remove the limit plate (9).

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