Construction method of high crown beam of pile-slab retaining wall

Abstract

The application discloses a pile-slab retaining wall high-altitude crown beam construction method, which comprises the following steps: S1, a construction preparation step, in which each formwork and support member is prepared; S2, a measurement and lofting step, in which measurement and lofting is performed on the retaining wall according to a formwork support design drawing; and S3, a support system installation step, which comprises the following steps: support installation, I-beam and adjustable inclined support installation, main and secondary beam installation of a bottom mould, and bottom mould installation, wherein the support is installed on the retaining plate of the pile-slab retaining wall, the main beam is connected with the support through the adjustable inclined support, the steel wedge is used for leveling, and finally the small beam and the bottom mould plate are laid to realize the crown beam construction.

Description

Technical Field

[0001] This invention belongs to the field of building construction technology, and in particular relates to a method for constructing a high-altitude cap beam for a pile-slab retaining wall. Background Technology

[0002] With the rapid development of my country's construction and municipal engineering industry, pile-slab retaining walls are becoming increasingly common as a retaining structure. Pile-slab retaining walls are suitable for slope protection, embankment slope support, and landslide control during earthwork excavation that may endanger adjacent buildings or the environment. Their main structure consists of reinforced concrete piles and reinforced concrete retaining slabs. Some pile-slab walls have a capping beam at the top of the piles. Reinforced concrete piles are typically rectangular or circular, and retaining slabs are classified as cast-in-place or precast depending on the manufacturing process.

[0003] The capping beam is typically a continuous reinforced concrete beam placed atop the perimeter support structure (mostly piles and walls) of the foundation pit. Its function is to connect all the pile foundations and bear the horizontal loads transmitted by the foundation pit support, forming a unified load-bearing structure and preventing collapse at the top edge of the foundation pit. Conventional capping beam construction involves excavating trenches along the location of the support piles on the ground, and then directly constructing the capping beam after the pile heads are treated. This method is clearly unsuitable for capping beams in pile-slab retaining walls. For pile-slab (square pile) retaining walls, capping beam construction usually involves backfilling the wall back to the bottom elevation of the capping beam before construction. Below the capping beam is the pile-slab wall with the backfill already completed, allowing for direct capping beam construction. However, due to the shape of the piles, pile-slab (round pile) retaining walls often use cast-in-place, centrally located retaining slabs, creating wide open surfaces on both sides of the retaining slabs. This necessitates the erection of capping beam formwork supports. Conventional formwork support construction of capping beams has limited applicability and economy due to the presence of retaining plates between piles. Furthermore, the capping beams of pile-slab (circular pile) retaining walls have large cross-sectional dimensions and high heights. Therefore, finding an economical and applicable construction method for high-altitude capping beams of pile-slab (circular pile) retaining walls is particularly important.

[0004] In existing technologies, the full-span scaffolding method has the following specific construction process: construction preparation → foundation treatment → full-span scaffolding erection → bottom formwork installation → full-span scaffolding pre-stressing → bottom formwork elevation adjustment → reinforcement installation → side formwork installation and reinforcement → concrete pouring → side formwork removal and curing → scaffolding removal. This construction method can achieve continuous overall pouring without the need to dismantle or move the scaffolding, avoiding construction interruptions caused by scaffolding removal and movement, and improving construction efficiency. However, its disadvantages are: 1. Full-span scaffolding deforms significantly under load, consumes a large amount of materials, and requires a large workload for civilized construction management; 2. Full-span scaffolding occupies a large area and should meet the height-to-width ratio requirement of no more than 3. For tall pile-slab (round pile) retaining wall capping beams, single-sided full-span scaffolding erection is not economical or applicable; 3. Full-span scaffolding requires high foundation bearing capacity and pre-stressing of the foundation and scaffolding, increasing the overall process time beyond the pre-stressing construction period.

[0005] In existing technologies, the through-hole steel bar method has the following specific construction process: construction preparation → pre-embedded sleeves in the pile body (pier) → steel bar installation → balance box installation → main beam adjustment device installation → longitudinal main beam installation → transverse distribution beam installation → bottom formwork installation → reinforcement installation → side formwork installation and reinforcement → concrete pouring → concrete curing → scaffold removal. The steel bar method does not occupy ground space and has no requirements for the foundation, making it easy to manage in a civilized manner. It can withstand large loads, and the scaffold deforms little under load. However, the steel bar method requires relatively large pre-embedded holes in the pile body. In pile-slab (round pile) retaining walls, the dense reinforcement in the pile body can conflict with the position of the main reinforcement, requiring adjustment or even cutting of the main reinforcement before construction can proceed, and affecting the appearance quality of the pile body (pier).

[0006] In existing technologies, the clamp method is used. The specific construction process is as follows: construction preparation → applying rubber layer → clamp installation and bolt tightening → sand cylinder installation → longitudinal main beam installation → transverse secondary beam installation → bottom formwork installation → reinforcement installation → side formwork installation and reinforcement → concrete pouring → concrete curing → clamp support removal. The clamp method has no requirements for the foundation, is simple to construct, has no height limit, is highly applicable, does not damage the appearance of the pier, and saves manpower and resources. However, 1. The clamp method uses the friction between the clamp and the pier to support the upper load.

[0007] If friction is lost, it can easily lead to safety accidents; 2. Pile-slab (round pile) retaining walls have retaining slabs between the piles.

[0008] If the retaining plate is thick, it will cause some difficulties in the construction of the retaining hoop. Summary of the Invention

[0009] The purpose of this invention is to overcome the problems of the prior art and disclose a method for constructing a high-altitude cap beam for a pile-slab retaining wall. In this invention, supports are installed on the retaining plate of the pile-slab retaining wall, the main beam is connected to the supports by adjustable diagonal braces, and steel wedges are used for leveling. Finally, small beams and bottom formwork are laid to realize the construction of the cap beam.

[0010] The objective of this invention is achieved through the following technical solution:

[0011] A method for constructing a high-altitude capping beam for a pile-slab retaining wall, the method comprising:

[0012] S1: Construction preparation steps, complete the preparation of each formwork and support component;

[0013] S2: Measurement and layout steps: Measure and layout the retaining wall according to the template support design drawings;

[0014] S3: Support system installation steps, including: support installation, I-beam and adjustable diagonal brace installation, bottom formwork main and secondary beam installation, and bottom formwork installation.

[0015] The construction of the cap beam is achieved by installing supports on the retaining plate of the pile-slab retaining wall, connecting the main beam to the supports with adjustable diagonal braces, leveling with steel wedges, and finally laying small beams and bottom formwork.

[0016] According to a preferred embodiment, step S1 further includes testing the concrete strength of the pile body and retaining plate of the pile-slab retaining wall before the capping beam is constructed to ensure that the structure is qualified.

[0017] According to a preferred embodiment, step S2 further includes arranging a dedicated person to be responsible for on-site construction measurement, and the location of each embedded part should be checked to ensure that the location of the embedded part is accurate.

[0018] According to a preferred embodiment, step S3 includes an embedded part installation step, wherein the embedded parts include support embedded parts and I-beam embedded parts.

[0019] PVC pipes are used as embedded parts for the support bolts. The embedded position is determined according to the elevation of the cap beam and the design drawings of the support system. The PVC pipes are fixed to the wall reinforcement mesh by binding and welding positioning bars to prevent them from floating or deviating during concrete pouring. The PVC pipes are reinforced with Φ16 steel mesh within a 20cm radius around them. When the embedded pipes conflict with the main reinforcement bars, the PVC pipes are finely adjusted according to the actual situation to stagger the main reinforcement bars. The ends of the PVC pipes are sealed with transparent tape and marked on both ends of the pipes to facilitate finding the holes after demolding.

[0020] The embedded parts of the I-beams are made into rectangular wooden boxes using wooden templates. They are fixed to the steel mesh of the wall by welding a grid of positioning bars. The top elevation of the wooden box is flush with the bottom elevation of the cap beam.

[0021] According to a preferred embodiment, in step S3, the support is formed by welding a custom steel plate and a hinged support lug plate, with round holes on the lug plate serving as pin installation positions.

[0022] During installation, the steel plate is fixed to the wall between the piles using four bolts. The horizontal and vertical positions of the steel plate are adjusted to ensure that the support is close to the wall and that each bolt is subjected to uniform force.

[0023] According to a preferred embodiment, in step S3, during the installation of the I-beam and adjustable diagonal brace, the length and spacing of the I-beam are determined according to the size of the cap beam. Hinged supports are welded below the I-beam. During installation, the outward extension length of the I-beam on both sides of the pile wall is consistent and fixed. The I-beam and the support are connected by the adjustable diagonal brace. The position of the hinged support is connected by a steel pin shaft, and leveling and elevation adjustment are performed.

[0024] The aforementioned main solution of the present invention and its various further alternative solutions can be freely combined to form multiple solutions, all of which are solutions that can be adopted and are claimed by the present invention. Those skilled in the art, after understanding the solution of the present invention, will realize that there are many combinations based on existing technology and common knowledge, all of which are technical solutions to be protected by the present invention, and will not be exhaustively listed here.

[0025] The beneficial effects of this invention are:

[0026] In the technical solution of this invention, a hinged support is set on the I-beam, and with the help of adjustable diagonal braces and steel wedges, it can adapt to different support heights and support angles according to different sizes of cap beams and installation environments, thus expanding the scope of application.

[0027] 1. This method allows the support frame to match the crown beam, resulting in a small horizontal projected area and no occupation of the foundation, thus solving the problem of large area occupation;

[0028] 2. The support is fixed with 4 bolts. The bolt diameter is much smaller than the spacing of the steel bars in the cast-in-place retaining plate. If there is any conflict, the support can be finely adjusted as a whole. There is no need to adjust the main reinforcement.

[0029] 3. The support can withstand the upper load through the shear resistance of 4 bolts, and is not limited by the thickness of the retaining plate;

[0030] 4. All components are recyclable, saving costs. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the process structure of the construction method of the pile-slab retaining wall high-altitude cap beam of the present invention;

[0032] Figure 2 Detail drawing of the hinged support for the retaining plate;

[0033] Figure 3 A schematic cross-sectional view of the retaining plate hinge support installation;

[0034] Figure 4 This is a detailed side elevation drawing of the I-beam main beam.

[0035] Figure 5 This is a detailed cross-sectional view of the I-beam main beam and hinged support.

[0036] Figure 6 Detailed schematic diagram of the connection of supporting components;

[0037] Figure 7 This is a schematic diagram of the installation cross-section of the support system;

[0038] Figure 8 A schematic diagram of the support system installation elevation;

[0039] Figure 9 This is a schematic diagram of the wedge block assembly.

[0040] Among them, 1-bolt, 2-nut, 3-retaining plate hinge support ear plate, 4-retaining plate hinge support base plate, 5-steel pin, 6-adjustable diagonal brace outer steel pipe, 7-adjustable diagonal brace inner thread rod, 8-adjustable diagonal brace adjusting component, 9-steel wedge, 10-I-beam, 11-I-beam hinge support base plate, 12-I-beam hinge support ear plate, 13-steel pipe, 14-timber, 15-film-coated plywood, 16-rectangular wooden box. Detailed Implementation

[0041] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0042] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0043] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0044] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0045] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0046] Furthermore, it should be noted that, unless otherwise specified, the structures, connections, positions, power sources, etc. involved in this invention are all things that a person skilled in the art can know without creative effort based on the prior art.

[0047] refer to Figure 1 As shown, this invention discloses a method for constructing a high-altitude capping beam for a pile-slab retaining wall. The method includes:

[0048] 1. Construction Preparation

[0049] (1) Entrust a professional manufacturer to process the template support components, and all components are inspected and accepted upon arrival.

[0050] (2) Before the construction of the cap beam, the concrete strength of the pile body and retaining plate of the pile-slab (circular pile) retaining wall is qualified.

[0051] 2. Measurement and layout

[0052] (1) Measure and lay out on the retaining wall according to the design drawings of the template support.

[0053] (2) Assign a dedicated person to be responsible for on-site construction measurement. The location of each embedded part should be checked to ensure that the location of the embedded part is accurate.

[0054] 3. Support system installation

[0055] Support system installation process: Embedded parts → Support installation → I-beams and adjustable diagonal braces → Steel wedge installation → Main and secondary beam installation of bottom formwork → Bottom formwork installation. Supports are installed on the retaining plate of the pile-slab (circular pile) retaining wall. Adjustable diagonal braces connect the main beams to the supports, and steel wedges are used for leveling. Finally, small beams and bottom formwork are laid to complete the capping beam construction.

[0056] (1) Installation of embedded parts

[0057] ① Support Embedded Parts

[0058] The support bolts use PVC pipes as embedded parts. The embedded position is determined according to the elevation of the cap beam and the design drawings of the support system. The embedded PVC holes are perpendicular to the axis of the wall, and the position of the embedded holes should be accurate.

[0059] PVC pipes are fixed to the wall reinforcement mesh by binding and welding positioning bars to prevent them from floating or shifting during concrete pouring. The PVC pipe is reinforced with Φ16 steel mesh within a 20cm radius around it. When the embedded pipe conflicts with the main reinforcement, the PVC pipe can be finely adjusted to offset the main reinforcement according to the actual situation. The ends of the PVC pipe are sealed with transparent tape and marked on both ends for easy locating of the hole after demolding.

[0060] ② H-beam embedded parts

[0061] The embedded parts for the I-beam installation slots are made into rectangular wooden boxes using wooden templates. They are then fixed to the wall reinforcement mesh by welding a grid of positioning bars. The top elevation of the wooden box is flush with the bottom elevation of the cap beam.

[0062] (2) Support installation

[0063] The bearings are factory-processed, using custom-made steel plates and hinged bearing lugs welded together (the lugs are fully welded on all four sides). Round holes are drilled in the lugs as pin installation positions. Four bolts are used to fix the steel plate to the wall between the piles, and the horizontal and vertical positions of the steel plate are adjusted. The bearings should be tightly fitted to the wall, and each bolt should be evenly stressed.

[0064] (3) I-beams and adjustable diagonal braces

[0065] The length and spacing of the I-beams are determined based on the dimensions of the capping beam. Hinged supports are welded below the I-beams. During installation, the outward extension length of the I-beams on both sides of the pile-slab wall is consistent and fixed. The I-beams and supports are connected by adjustable diagonal braces. The positions of the hinged supports are connected by steel pins, and leveling and elevation adjustments are performed.

[0066] (4) Steel wedge installation

[0067] To facilitate the adjustment and dismantling of the I-beam main beam, steel wedge blocks are manufactured to adjust the elevation of the I-beam main beam. The wedge blocks are processed in the factory.

[0068] (5) Installation of small beams and bottom formwork

[0069] The longitudinal beams are made of steel pipes, and the bottom formwork is made of wood. Wooden strips are set on both sides of the steel pipes to fix the wooden bottom formwork.

[0070] In this technical solution, hinged supports are installed on the I-beams, and adjustable diagonal braces and steel wedges are used to adapt to different support heights and angles according to different sizes of cap beams and installation environments, thus expanding the scope of application.

[0071] 1. This method allows the support frame to match the crown beam, resulting in a small horizontal projected area and no occupation of the foundation, thus solving the problem of large area occupation;

[0072] 2. The support is fixed with 4 bolts. The bolt diameter is much smaller than the spacing of the steel bars in the cast-in-place retaining plate. If there is any conflict, the support can be finely adjusted as a whole. There is no need to adjust the main reinforcement.

[0073] 3. The support can withstand the upper load through the shear resistance of 4 bolts, and is not limited by the thickness of the retaining plate;

[0074] 4. All components are recyclable, saving costs.

[0075] Example 1

[0076] refer to Figures 2 to 9 As shown in the figure, a structural schematic diagram of the cap beam construction process is presented.

[0077] (1) Install bolt 1 on the PVC sleeve of the retaining plate, and then install the hinge support (retaining plate hinge support ear plate 3, retaining plate hinge support bottom plate 4). Use nut 2 to fix the retaining plate hinge support bottom plate 4 on bolt 1.

[0078] (2) Place the I-beam 10 on the rectangular wooden box 16;

[0079] (3) An adjustable diagonal brace (adjustable diagonal brace outer steel pipe 6, adjustable diagonal brace inner screw rod 7, adjustable diagonal brace adjustment piece 8) is used to connect the I-beam hinge support (I-beam hinge support base plate 11, I-beam hinge support ear plate 12) to the retaining plate hinge support (retaining plate hinge support ear plate 3, retaining plate hinge support base plate 4). The ear plates are connected by a steel pin shaft 5.

[0080] (4) Adjust the elevation of the I-beam 10 by means of adjustable diagonal bracing (adjustable diagonal bracing outer steel pipe 6, adjustable diagonal bracing inner screw 7, adjustable diagonal bracing adjusting component 8), and install rigid wedges 9 to fix and support the I-beam 10.

[0081] (5) Install steel pipe 13 and timber 14 on I-beam 10, and fix film-coated plywood 15 on timber 14.

[0082] (6) Finally, install the cap beam reinforcement, side formwork, and pour concrete.

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for constructing a high-altitude capping beam for a pile-slab retaining wall, characterized in that, The construction method for the high-altitude cap beam of the pile-slab retaining wall includes: S1: Construction preparation steps, complete the preparation of each formwork and support component; S2: Measurement and layout steps: Measure and layout the retaining wall according to the template support design drawings; S3: Support system installation steps, including: support installation, I-beam and adjustable diagonal brace installation, bottom formwork main and secondary beam installation, and bottom formwork installation. By installing supports on the retaining plate of the pile-slab retaining wall, connecting the main beam to the supports with adjustable diagonal braces, leveling with steel wedges, and finally laying small beams and bottom formwork, the cap beam construction is achieved. Step S1 also includes testing the concrete strength of the pile body and retaining plate of the pile-slab retaining wall before the capping beam is constructed to ensure that the structure is qualified. Step S2 also includes assigning a dedicated person to be responsible for on-site construction measurement, and the location of each embedded part should be checked to ensure that the location of the embedded part is accurate; Step S3 includes the installation of embedded parts, which include support embedded parts and I-beam embedded parts. PVC pipes are used as embedded parts for the support bolts. The embedded position is determined according to the elevation of the cap beam and the design drawings of the support system. The PVC pipes are fixed to the wall reinforcement mesh by binding and welding positioning bars to prevent them from floating or deviating during concrete pouring. The PVC pipes are reinforced with Φ16 steel mesh within a 20cm radius around them. When the embedded pipes conflict with the main reinforcement bars, the PVC pipes are finely adjusted according to the actual situation to stagger the main reinforcement bars. The ends of the PVC pipes are sealed with transparent tape and marked on both ends for easy hole location after demolding. The embedded parts of the I-beams are made into rectangular wooden boxes using wooden templates. They are fixed to the steel mesh of the wall by welding a grid of positioning bars. The top elevation of the wooden box is flush with the bottom elevation of the cap beam. In step S3, the support is formed by welding a custom steel plate and a hinged support ear plate. Round holes are drilled on the ear plate as locations for pin installation. During installation, the steel plate is fixed to the wall between the piles using four bolts. The horizontal and vertical positions of the steel plate are adjusted to ensure that the support is close to the wall and that each bolt is subjected to uniform force. In step S3, during the installation of the I-beams and adjustable braces, the length and spacing of the I-beams are determined according to the size of the cap beam. Hinged supports are welded below the I-beams. During installation, the outward extension length of the I-beams on both sides of the pile wall is consistent and fixed. The I-beams and supports are connected by adjustable braces. The position of the hinged supports is connected by steel pins, and leveling and elevation adjustment are performed.

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