Prefabricated concrete u-shaped structure and construction method

Abstract

The application provides an assembled concrete U-shaped structure and a construction method. The assembled concrete U-shaped structure comprises a prefabricated bottom plate, a first prefabricated side wall and a second prefabricated side wall. The first prefabricated side wall and the second prefabricated side wall are symmetrically arranged on both sides of the prefabricated bottom plate. A first connecting steel bar is arranged on the first prefabricated side wall opposite to the prefabricated bottom plate. A second connecting steel bar is arranged on the second prefabricated side wall opposite to the prefabricated bottom plate. Third connecting steel bars are arranged at both ends of the prefabricated bottom plate. The third connecting steel bars are poured into a single U-shaped structure with the first connecting steel bars and the second connecting steel bars through cast-in-situ belts. Two adjacent single U-shaped structures are poured into a whole through a transverse cast-in-situ belt. The prefabricated assembly method has the advantages of green environmental protection, small construction interference, high speed and the like. The permanent and temporary combination optimizes the cross-sectional size of the traditional roadbed U-shaped structure, and achieves the effects of reliable stress, good integrity, efficient assembly, saved construction period, saved land, reduced earthwork engineering and environmental protection.

Description

Technical Field

[0001] This invention relates to the field of roadbed structure construction, and in particular to a prefabricated concrete U-shaped structure and its construction method. Background Technology

[0002] U-shaped roadbed structures are widely used in highways, railways, urban rail transit, and municipal engineering. They are often used to solve problems such as poor soil excavation conditions, high groundwater levels, and limited structural space in road cutting projects, offering advantages such as safety, reliability, and land saving. However, traditional roadbed U-shaped structures are constructed entirely with cast-in-place reinforced concrete. As the height of the side walls increases, the structural dimensions increase rapidly, requiring a large number of formwork supports and rebar ties, often resulting in long construction cycles and low construction efficiency. In particular, for road cutting U-shaped structures, the foundation pit retaining and protection structures and water-stopping measures still need to be constructed in advance before the U-shaped structure construction. These measures serve as temporary protection and become completely ineffective within a few years after completion, not only restricting the construction period but also causing a certain amount of material waste.

[0003] Prefabricated structures, as a type of prefabricated assembly structure, utilize factory prefabrication and rapid on-site installation, significantly reducing construction time and solving the problem of long construction cycles associated with traditional U-shaped roadbed structures. However, considering the limitations of conventional hoisting and transportation machinery, prefabricated components should be lightweight and simplified, which contradicts the characteristic of deep foundation pits where increased stress with greater depth necessitates larger cross-sectional dimensions. Furthermore, ensuring the integrity of component connections and achieving good mechanical properties and waterproofing are also crucial challenges in applying prefabricated structures.

[0004] Therefore, inventing a prefabricated U-shaped structure that can leverage the construction advantages of prefabricated structures, solve the problem of long construction periods of traditional U-shaped structures, possess excellent mechanical and waterproof properties, address the issue of material waste in temporary protective measures of traditional U-shaped structures, and meet the high requirements of high-speed railways for settlement and track smoothness is of great significance to the development of roadbed engineering. Summary of the Invention

[0005] In view of this, the present invention aims to propose a prefabricated concrete U-shaped structure and construction method, which takes advantage of the advantages of prefabrication and assembly methods such as being green and environmentally friendly, having little construction interference, and being fast, and overcomes the shortcomings of existing technologies to meet the requirements of reliable stress, good integrity, and efficient assembly.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A prefabricated concrete U-shaped structure includes a precast base slab, a first precast side wall, and a second precast side wall. The first and second precast side walls are symmetrically arranged on both sides of the precast base slab. A first connecting steel bar is provided on the first precast side wall opposite to the precast base slab, and a second connecting steel bar is provided on the second precast side wall opposite to the precast base slab. A third connecting steel bar is provided at both ends of the precast base slab. The third connecting steel bar is cast together with the first and second connecting steel bars through a longitudinal cast-in-place strip to form a single U-shaped structure. Two adjacent single U-shaped structures are cast together as a whole through a transverse cast-in-place strip, thus completing the construction of the prefabricated concrete U-shaped structure.

[0007] Furthermore, the precast base slab, the first precast side wall, and the second precast side wall are precast together and then transported to the site for hoisting and positioning.

[0008] Furthermore, support piles are provided on the outer sides of both the first and second precast side walls. In the first and second precast side walls, internal anchor bars are longitudinally arranged along the height direction of the precast side walls. External anchor bars are provided in the support piles. The internal and external anchor bars are connected by steel bar connectors and anchored to the support piles. The structure is cast in place with concrete to form a whole, thus creating a road cut type prefabricated U-shaped structure.

[0009] Furthermore, cast-in-place base slabs or supporting beams are provided at the bottom of the precast base slab, the first precast side wall, and the second precast side wall to enhance the overall structural integrity and the bending and buoyancy resistance of the bottom of the structure, and mid-span reinforcing piles are provided to control the deflection deformation of the base slab with a large span.

[0010] Furthermore, the cast-in-place base slab or supporting beam is anchored to the support piles through circumferential anchor bars and dowel bars of the support piles. The circumferential anchor bars of the support piles are arranged parallel to the cast-in-place base slab or supporting beams, and the gap between the cast-in-place base slab and the support piles is sealed by concrete between the cast-in-place base slab piles.

[0011] Furthermore, the reinforcing bars of the support piles are arranged in a radiating pattern from the support piles along the direction of the cast-in-place base slab or supporting beam.

[0012] Furthermore, a support pile cap beam is provided at the upper end of the support pile, and an outer side wall anchor bar is provided inside the support pile cap beam. The inner side wall anchor bar is connected to the outer side wall anchor bar inside the support pile cap beam through a steel bar connector. Water-stop curtains are provided on both sides of the support pile, and composite foundation treatment is carried out at the bottom of the cast-in-place foundation slab.

[0013] Furthermore, the precast base slab, the first precast side wall, and the second precast side wall are all anchored to the cast-in-place base slab by anchoring steel bars, and are cast into a whole by cast-in-place strips composed of longitudinal and transverse cast-in-place strips; a waterproof layer is provided between the precast base slab, the first precast side wall, the second precast side wall and the cast-in-place base slab or the supporting beam, and the steel bar penetration parts are sealed by local reinforced waterproofing measures (i.e., using water-stop rings and setting water-swellable water-stop strips).

[0014] Furthermore, the first and second precast side walls are suspended above the ground, and roadbed filler is set inside the prefabricated concrete U-shaped structure. A cushion layer can be set at the bottom as needed according to the geological characteristics, and composite foundation treatment is carried out to form an embankment-type prefabricated U-shaped structure.

[0015] The above-mentioned construction method for a prefabricated concrete U-shaped structure includes the following steps: Step 1: The precast base slab, the first precast side wall, and the second precast side wall are precast together and then transported to the site; Step 2: Level the site, construct foundation pit support measures (support piles, support pile cap beams), excavate the foundation pit and set up temporary support measures (water-stop curtain). Step 3: Construct the cast-in-place base slab or supporting beam, roughen the connection points of the retaining structure (support piles), tie the reinforcing bars of the cast-in-place base slab or supporting beam, and pour concrete; Step 4: After the cast-in-place base slab or supporting beams reach the design strength, gradually remove the temporary supports and construct the prefabricated concrete U-shaped structure with an outer waterproof layer (waterproof layer and leveling layer). Step 5: Hoist the precast concrete U-shaped structure components, ensuring that the precast components are tightly bonded to the waterproof layer, and use temporary supports or other anti-overturning measures to ensure the stability of the precast components; Step 6: Tie the reinforcing bars at the location of the cast-in-place strip, and use anchoring bars (inner anchoring bars in the side wall, outer anchoring bars in the side wall, rebar connectors, and anchoring bars in the precast base slab) to connect the precast concrete U-shaped structure with the support structure and the cast-in-place base slab or supporting beam. Step 7: Pour the cast-in-place concrete strip. After the cast-in-place concrete reaches the design strength, remove the anti-overturning measures for the precast components. Step 8: Construct the canopy structure and roadbed ancillary structures.

[0016] Compared with existing technologies, the prefabricated concrete U-shaped structure and construction method described in this invention have the following advantages: (1) The precast base plate and precast side wall are precast in a centralized manner, which makes it easy to control the construction quality, easy to assemble, fast to construct, and saves the construction period; the construction accuracy is high, which makes it easier to meet the smoothness requirements of high-speed railway lines.

[0017] (2) The pre-reserved cast-in-place strips and connecting steel bars between different assembled components are anchored and fixed to the retaining structure. The structure has good integrity and can give full play to the mechanical properties of the retaining structure. It can not only strengthen the structure's anti-buoyancy ability, but also help reduce settlement. The structure is safe and reliable.

[0018] (3) Combining the retaining structure with the prefabricated U-shaped structure, the retaining structure, as a permanent structure, bears the main load, realizing the combination of permanent and temporary, avoiding material waste, while meeting the lightweight design requirements of the U-shaped structure, saving engineering land and being environmentally friendly.

[0019] (4) This invention leverages the advantages of prefabricated assembly methods, such as being green and environmentally friendly, having minimal construction interference, and being fast. It combines permanent and temporary construction, optimizes the cross-sectional dimensions of traditional roadbed U-shaped structures, improves the shortcomings of existing technologies, and achieves the effects of reliable stress, good integrity, efficient assembly, saving construction time, saving land, reducing earthwork, and being environmentally friendly. Attached Figure Description

[0020] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of the main structure of the present invention; Figure 2 This is a schematic diagram of the main view structure of the present invention applied to a road cut type prefabricated U-shaped structure; Figure 3 This is a schematic diagram of the main structure of the present invention applied to an embankment-type prefabricated U-shaped structure; Figure 4 yes Figure 2 Section II view; Figure 5 yes Figure 3 Section V-V; Figure 6 yes Figure 1 Section II-II; Figure 7 yes Figure 6 Section IV-IV; Figure 8 yes Figure 2 Section III-III view; Figure 9 yes Figure 5 Section VI-VI; Figure 10 This is an example diagram of the U-shaped prefabricated concrete structure for road cuts according to the present invention; Figure 11 This is an example diagram of the prefabricated concrete U-shaped structure for embankments according to the present invention.

[0021] Explanation of reference numerals in the attached figures: 1. First precast sidewall; 1-1. First connecting reinforcement; 1-2. Inner anchoring reinforcement of sidewall; 1-3. Outer anchoring reinforcement of sidewall; 1-4. Reinforcing bar connector; 2. Precast base slab; 2-1. Third connecting reinforcement; 2-2. Anchoring reinforcement; 3. Second precast sidewall; 3-1. Second connecting reinforcement; 4. Cast-in-place strip; 4-1. Longitudinal cast-in-place strip; 4-2. Transverse cast-in-place strip; 5. Waterproof layer and leveling layer; 6. Support pile capping beam; 7. Still water curtain; 8. Support piles; 8-1. Circumferential anchor bars for support piles; 8-2. Inserted bars for support piles; 9. Foundation sealing and reinforcement structure; 10. Mid-span reinforcement piles; 11. Cast-in-place foundation slab; 11-1 Cast-in-place foundation slab pile spacing concrete; 12. Foundation reinforcement structure. Detailed Implementation

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the 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 the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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 will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] like Figure 1 As shown, a prefabricated concrete U-shaped structure includes a precast base slab 2, a first precast side wall 1, a second precast side wall 3, inner anchor bars 1-2, outer anchor bars 1-3, anchor bars 2-2, a first connecting bar 1-1, a third connecting bar 2-1, and a second connecting bar 3-1. The precast base slab 2, the first precast side wall 1, and the second precast side wall 3 are precast centrally and transported to the site for hoisting and positioning. The first precast side wall 1 and the second precast side wall 3 are symmetrically arranged on the left and right sides and assembled with the precast base slab 2 to form a single U-shaped structure. The first connecting bar 1-1, the third connecting bar 2-1, and the second connecting bar 3-1, along with the longitudinal cast-in-place strip 4-1, are poured to form a single U-shaped structure. The blocks are connected by transverse cast-in-place strips 4-2 to form a whole, completing the construction of the prefabricated U-shaped structure.

[0027] The prefabricated concrete U-shaped structure can be designed according to the slope of the line and the top slope of the side wall, and different component sizes can be made as needed, so that the overall structure formed by assembling multiple individual U-shaped structures is continuous and beautiful.

[0028] The prefabricated concrete U-shaped structure, in deep foundation pit road cutting sections, is combined with retaining structures such as bored piles and manually excavated piles (support piles 8), as well as water-stop curtains 7, dewatering wells, foundation bottom sealing and reinforcement structures 9, and composite foundation treatment, to form a road cutting type prefabricated U-shaped structure.

[0029] The prefabricated U-shaped structure for road cuts has U-shaped structural components located inside the retaining structure. Anchor steel bars (inner side wall anchor bars 1-2, outer side wall anchor bars 1-3, and steel bar connectors 1-4) are longitudinally installed between the individual U-shaped structural blocks along the height direction of the side wall to connect and anchor with the retaining structure, and are cast in place with concrete to form a whole.

[0030] The retaining structure (support pile 8) serves as the main load-bearing component, acting as both the retaining structure for the foundation pit project and the permanent retaining structure on the outside of the prefabricated U-shaped structure. It withstands external water and soil pressure, achieving a combination of permanent and temporary support.

[0031] A leveling layer, a waterproof layer, and waterproof materials (waterproof layer and leveling layer 5) are provided between the support structure and the prefabricated U-shaped structure. The penetration points of the anchoring steel bars are sealed with localized reinforced waterproofing measures.

[0032] The bottom of the prefabricated concrete U-shaped structure can be equipped with a cast-in-place base slab 11 or a supporting beam to enhance the overall structure and the bending and buoyancy resistance of the bottom of the structure. Mid-span reinforcing piles 10 are also installed to control the deflection deformation of the base slab with a large span.

[0033] The cast-in-place base slab 11 or supporting beam is anchored to the retaining structure (support pile 8) through anchoring steel bars 8-1 and 8-2. The gap between the cast-in-place base slab and the retaining structure (support pile 8) is sealed by the concrete 11-1 between the cast-in-place base slab piles. The prefabricated U-shaped structure is anchored by anchoring steel bars 2-2 and is cast into a whole by a cast-in-place strip 4 composed of longitudinal cast-in-place strip 4-1 and transverse cast-in-place strip 4-2. A waterproof layer is set between the cast-in-place base slab or supporting beam and the prefabricated U-shaped structure, and the parts where the steel bars penetrate are sealed by local reinforced waterproofing measures.

[0034] like Figure 3 and Figure 11 As shown, the prefabricated concrete U-shaped structure, in relatively flat embankment sections, is combined with foundation reinforcement measures to form an embankment-type prefabricated U-shaped structure.

[0035] The embankment-type prefabricated U-shaped structure has a first prefabricated sidewall 1 and a second prefabricated sidewall 3 that are suspended above the ground. The prefabricated U-shaped structure is equipped with roadbed filling material. The bottom of the structure can be equipped with a cushion layer and a foundation reinforcement structure 12 as needed according to the geological characteristics, and a composite foundation treatment can be carried out.

[0036] The embankment-type prefabricated U-shaped structure has itself as the main load-bearing component, and the load is mainly the filling material inside the U-shaped structure, the roadbed structure, and the train load.

[0037] The above-mentioned construction method for a prefabricated concrete U-shaped structure includes the following steps: Step 1: The precast base slab 2, the first precast side wall 1, and the second precast side wall 3 are precast together and then transported to the site.

[0038] Step 2: Level the site, construct foundation pit support measures (support piles 8, support pile cap beam 6), excavate the foundation pit and set up temporary support measures (water-stop curtain 7).

[0039] Step 3: Construct the cast-in-place base slab 11 or supporting beam, roughen the connection position of the retaining structure (support pile 8), tie the reinforcing bars of the cast-in-place base slab 11 or supporting beam, and pour concrete.

[0040] Step 4: After the cast-in-place base slab or supporting beams reach the design strength, gradually remove the temporary supports and construct the prefabricated U-shaped channel structure with an outer waterproof layer (waterproof layer and leveling layer 5).

[0041] Step 5: Hoist the prefabricated U-shaped structure components, ensuring that the prefabricated components are tightly attached to the waterproof layer, and use temporary supports or other anti-overturning measures inside to ensure the stability of the prefabricated components.

[0042] Step Six: Tie the reinforcing bars at the location of the cast-in-place strip, and use anchoring bars (inner side wall anchoring bars 1-2, outer side wall anchoring bars 1-3, reinforcing bar connectors 1-4, anchoring bars 2-2) to connect the prefabricated U-shaped structure with the support structure and the cast-in-place base slab or supporting beam.

[0043] Step 7: Pour the concrete for the cast-in-place strip 4. After the cast-in-place concrete reaches the design strength, remove the anti-overturning measures for the precast components.

[0044] Step 8: Construct the canopy structure and roadbed ancillary structures.

[0045] 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, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A prefabricated concrete U-shaped structure, characterized in that: The structure includes a precast base slab, a first precast side wall, and a second precast side wall. The first and second precast side walls are symmetrically arranged on both sides of the precast base slab. A first connecting steel bar is provided on the first precast side wall opposite to the precast base slab, and a second connecting steel bar is provided on the second precast side wall opposite to the precast base slab. A third connecting steel bar is provided at both ends of the precast base slab. The third connecting steel bar is cast together with the first and second connecting steel bars through a longitudinal cast-in-place strip to form a single U-shaped structure. Two adjacent single U-shaped structures are cast together as a whole through a transverse cast-in-place strip. Support piles are provided on the outer sides of the first and second precast side walls. In the first and second precast side walls, internal anchor bars are set longitudinally along the height direction of the precast side walls. External anchor bars are set in the support piles. The internal and external anchor bars are connected by steel bar connectors and anchored to the support piles. The structure is cast in place with concrete to form a whole, and is assembled to form a road cut type prefabricated U-shaped structure. Cast-in-place base slabs or supporting beams are installed at the bottom of the precast base slab, the first precast side wall, and the second precast side wall, and mid-span reinforcing piles are installed.

2. The prefabricated concrete U-shaped structure according to claim 1, characterized in that: The precast base slab, the first precast side wall, and the second precast side wall are precast together, transported to the site, and then hoisted and positioned.

3. The prefabricated concrete U-shaped structure according to claim 1, characterized in that: The cast-in-place base slab or supporting beam is anchored to the support piles through circumferential anchor bars and dowel bars. The circumferential anchor bars are arranged parallel to the cast-in-place base slab or supporting beam. The gap between the cast-in-place base slab and the support piles is sealed by concrete between the cast-in-place base slab and the piles.

4. A prefabricated concrete U-shaped structure according to claim 3, characterized in that: The reinforcing bars of the support piles are arranged in a radiating pattern from the support piles along the direction of the cast-in-place base slab or supporting beam.

5. A prefabricated concrete U-shaped structure according to claim 1 or 4, characterized in that: A support pile cap beam is provided at the upper end of the support pile, and an outer side wall anchor bar is provided inside the support pile cap beam. The inner side wall anchor bar is connected to the outer side wall anchor bar inside the support pile cap beam through a steel bar connector. Water-stop curtains are provided on both sides of the support pile, and composite foundation treatment is carried out at the bottom of the cast-in-place foundation slab.

6. A prefabricated concrete U-shaped structure according to claim 5, characterized in that: The precast base slab, the first precast side wall, and the second precast side wall are all anchored to the cast-in-place base slab by anchoring steel bars, and are cast into a whole by cast-in-place strips composed of longitudinal and transverse cast-in-place strips; a waterproof layer is provided between the precast base slab, the first precast side wall, the second precast side wall and the cast-in-place base slab or the supporting beam.

7. A construction method for a prefabricated concrete U-shaped structure according to any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1: The precast base slab, the first precast side wall, and the second precast side wall are precast together and then transported to the site; Step 2: Level the site, construct foundation pit support measures, excavate the foundation pit and set up temporary support measures; Step 3: Construct the cast-in-place base slab or supporting beam, roughen the connection points of the support piles, tie the reinforcing bars of the cast-in-place base slab or supporting beam, and pour concrete. Step 4: After the cast-in-place base slab or supporting beams reach the design strength, gradually remove the temporary supports and construct the prefabricated concrete U-shaped structure with an outer waterproof layer. Step 5: Hoist the precast concrete U-shaped structure components, ensuring a tight fit between the precast components and the waterproof layer, and use temporary internal supports to ensure the stability of the precast components; Step Six: Tie the reinforcing bars at the location of the cast-in-place strip, and use anchoring bars to connect the precast concrete U-shaped structure with the support structure and the cast-in-place base slab or supporting beam; Step 7: Pour the cast-in-place concrete strip. After the cast-in-place concrete reaches the design strength, remove the anti-overturning measures for the precast components. Step 8: Construct the canopy structure and roadbed ancillary structures.

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