Prestressed steel reinforced concrete asymmetric braced structure and construction method thereof

Abstract

The application discloses a prestressed steel reinforced concrete asymmetric support structure and a construction method thereof, two layers of supports are arranged on the inner and outer sides of a surrounding pile adjacent to an existing building structure, the two layers of supports on each side of the surrounding pile are arranged at intervals along the axial direction of the surrounding pile, the two layers of supports on the outer side of the surrounding pile are arranged between the two layers of supports on the inner side of the surrounding pile, the support bodies on the outer side of the surrounding pile and the support bodies on the inner side of the surrounding pile are alternately arranged, the support bodies on the inner and outer sides of the surrounding pile are arranged in the same direction, a plurality of inclined braces are connected between the upper part of the load-bearing purlin of the upper layer of supports and the surrounding pile, and a plurality of inclined braces are connected between the lower part of the load-bearing purlin of the lower layer of supports and the surrounding pile to form an asymmetric support structure, so that the deformation of a deep foundation pit is better controlled, and the safety of surrounding buildings, roads and underground pipeline projects is protected. The application solves the problem that the maintenance structure is prone to deformation in the deep foundation pit construction process adjacent to the existing building structure.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, specifically to a prestressed steel-reinforced concrete asymmetric support structure and its construction method. Background Technology

[0002] With the rapid development of urban construction, the excavation of deep foundation pits is constantly expanding in size and depth. Deep foundation pit projects are generally located in relatively busy areas, surrounded by buildings, underground pipelines, and congested roads. The environmental impact of soil excavation is also highly sensitive, leading to increasingly stringent requirements for the protection of surrounding buildings, roads, and underground pipelines. During the excavation process, it is crucial to strictly control the deformation of the deep foundation pit; otherwise, it will have a significant impact on the surrounding environment. Therefore, protecting the surrounding environment has become a key focus of deep foundation pit support engineering. Deep foundation pit support not only requires safe and reliable construction but also demands control over the impact of excavation on the surrounding environment. Like ordinary reinforced concrete, prestressed concrete relies on the tension of the steel reinforcement and the compression of the concrete to provide internal resistance moments; therefore, prestressed concrete does not increase the flexural bearing capacity of the cross-section.

[0003] In order to effectively control the deformation of the retaining structure during the support formwork, rebar tying and concrete pouring processes in the foundation pit construction, it is necessary to design a deformation control method based on prestressed steel-reinforced concrete supports.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of the invention and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, a prestressed steel-reinforced concrete asymmetric support structure and its construction method are provided to solve the problem of easy deformation of the support structure during the construction of deep foundation pits adjacent to existing buildings.

[0006] To achieve the above objectives, a prestressed steel-reinforced concrete asymmetric support structure is provided, comprising:

[0007] The support includes the inner and outer sides of multiple retaining piles installed in the foundation pit. Two layers of support are provided on both the inner and outer sides of each retaining pile. The two layers of support on each side of the retaining pile are spaced apart along the axial direction of the retaining pile. The two layers of support on the outer side of the retaining pile are positioned between the two layers of support on the inner side of the retaining pile. Each layer of support includes:

[0008] Load-bearing purlins are installed on multiple of the aforementioned retaining piles;

[0009] Multiple support bodies are connected to the load-bearing purlin. The multiple support bodies are spaced apart along the length of the purlin. The multiple support bodies on the outer side of the retaining pile and the multiple support bodies on the inner side of the retaining pile are alternately arranged. The support bodies on the inner and outer sides of the retaining pile are arranged in the same direction.

[0010] The upper part of the upper supporting purlin is connected to the retaining pile by multiple diagonal braces, and the lower part of the lower supporting purlin is connected to the retaining pile by multiple diagonal braces. The position of the diagonal braces on the outer side of the retaining pile, away from the supporting purlin, corresponds to the position of the supporting purlin on the inner side of the retaining pile.

[0011] Furthermore, the supporting body includes:

[0012] Precast concrete supports are erected within the foundation pit via lattice columns;

[0013] Two supporting steel members, one end of which is connected to the load-bearing purlin, and the other end of which is opposite to the end face of the precast concrete support. The two supporting steel members are arranged on opposite sides of the end face of the precast concrete support. The other end of the two supporting steel members is connected to a first pressure-bearing member, and the end face is connected to a second pressure-bearing member.

[0014] A axial force jack is positioned between the first pressure-bearing component and the second pressure-bearing component;

[0015] A pressure-retaining box is placed between the first pressure-bearing component and the second pressure-bearing component;

[0016] The first concrete is used to cover the two supporting steel frames, the axial force jack, the force-holding box, the first pressure-bearing component, and the second pressure-bearing component.

[0017] Furthermore, the load-bearing purlin includes:

[0018] The connecting steel frame is connected to multiple retaining piles, and one end of each of the two supporting steel frames of the supporting body is connected to the connecting steel frame;

[0019] A steel reinforcement structure is fitted over the outside of the connecting steel frame;

[0020] The second concrete is used to encapsulate the connecting steel frame and the reinforcing steel structure.

[0021] Furthermore, each of the supports is connected to the retaining piles by two diagonal braces. The other end of one diagonal brace is connected to the connecting steel frame, and the other end of the other diagonal brace is connected to the steel reinforcement structure. The other ends of the two diagonal braces are embedded in the second concrete.

[0022] Furthermore, the inclination angle of the diagonal brace is 45°.

[0023] Furthermore, a lattice column is inserted between the two supporting steel frames.

[0024] This invention provides a construction method based on a prestressed steel-reinforced concrete asymmetric support structure, comprising the following steps:

[0025] A construction water-stop curtain is provided, which is set in a circle around the perimeter of the foundation pit;

[0026] Multiple retaining piles are poured inside the water-stop curtain, so that the multiple retaining piles are arranged in a circle along the circumferential direction of the foundation pit.

[0027] The excavation of the foundation pit is carried out in layers. After each layer of excavation, load-bearing purlins are installed on both the inner and outer sides of multiple retaining piles. Multiple support bodies are connected to the load-bearing purlins. The multiple support bodies are spaced apart along the length of the purlins. The multiple support bodies on the outer side of the retaining piles are alternately arranged with the multiple support bodies on the inner side of the retaining piles. The support bodies on the inner and outer sides of the retaining piles are arranged in the same direction. Multiple diagonal braces are connected between the upper part of the load-bearing purlins of the upper layer of support and the retaining piles. Multiple diagonal braces are connected between the lower part of the load-bearing purlins of the lower layer of support and the retaining piles. The position of the diagonal braces of the two layers of support on the outer side of the retaining piles, away from the load-bearing purlins, corresponds to the position of the load-bearing purlins on the inner side of the retaining piles, thus forming an asymmetric support structure based on prestressed steel-reinforced concrete.

[0028] The beneficial effects of this invention are as follows: Based on the prestressed steel-reinforced concrete asymmetric support structure, two layers of support are set on the inner and outer sides of the retaining piles adjacent to the existing building structure. The two layers of support on each side of the retaining pile are spaced apart along the axial direction of the retaining pile. The two layers of support on the outer side of the retaining pile are set between the two layers of support on the inner side of the retaining pile. The multiple support bodies on the outer side of the retaining pile and the multiple support bodies on the inner side of the retaining pile are alternately set. The support bodies on the inner and outer sides of the retaining pile are set in the same direction. The upper part of the load-bearing purlin of the upper support is connected to the retaining pile by multiple diagonal braces. The lower part of the load-bearing purlin of the lower support is connected to the retaining pile by multiple diagonal braces. The position of the diagonal braces of the two layers of support on the outer side of the retaining pile away from the load-bearing purlin corresponds to the position of the load-bearing purlin on the inner side of the retaining pile to form an asymmetric support structure, thereby better controlling the deformation of the deep foundation pit and protecting the safety of surrounding buildings, roads, and underground pipeline projects. Attached Figure Description

[0029] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0030] Figure 1This is a schematic diagram of a prestressed steel-reinforced concrete asymmetric support structure according to an embodiment of the present invention.

[0031] Figure 2 This is a cross-sectional view of an embodiment of the present invention based on a prestressed steel-reinforced concrete asymmetric support structure.

[0032] Figure 3 This is a top view of the support structure in an embodiment of the present invention.

[0033] Figure 4 for Figure 3 The sectional view at point AA.

[0034] Figure 5 for Figure 3 The sectional view at point BB.

[0035] Figure 6 for Figure 3 The sectional view at point CC.

[0036] Figure 7 for Figure 3 The sectional view at point DD. Detailed Implementation

[0037] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0038] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0039] Reference Figures 1 to 7 As shown, this invention provides an asymmetric support structure based on prestressed steel-reinforced concrete, including supports. Specifically, as... Figure 1 and Figure 2 As shown, multiple retaining piles are embedded within the foundation pit. These retaining piles form a ring around the circumference of the foundation pit. A water-stop curtain is installed on the outer side of the retaining piles, also forming a ring around the circumference of the foundation pit.

[0040] Two layers of support are installed on both the inner and outer sides of the multiple retaining piles 4. Each layer of support includes multiple supports, that is, two layers of support are installed on the inner side of the multiple retaining piles 4, and two layers of support are installed on the outer side of the multiple retaining piles 4.

[0041] Two layers of supports on each side of the retaining pile 4 are spaced apart along the axial direction of the retaining pile 4. The two layers of supports on the outer side of the retaining pile 4 are located between the two layers of supports on the inner side of the retaining pile 4.

[0042] Each support includes: a load-bearing purlin 1, a support body 2, and a diagonal brace 3.

[0043] The load-bearing purlin 1 is installed on one side of the retaining piles 4. Specifically, the load-bearing purlin is installed on one side of the retaining piles.

[0044] The support body 2 is connected to the load-bearing purlin 1. Each load-bearing purlin is connected to multiple support bodies. The multiple support bodies 2 are spaced apart along the length of the purlin. The multiple support bodies 2 on the outer side of the retaining pile 4 are alternately arranged with the multiple support bodies 2 on the inner side of the retaining pile 4. The support bodies 2 on both the inner and outer sides of the retaining pile 4 are arranged in the same direction.

[0045] Multiple diagonal braces 3 connect the upper part of the upper supporting purlin 1 to the retaining pile 4. Multiple diagonal braces 3 also connect the lower part of the lower supporting purlin 1 to the retaining pile 4. The positions of the diagonal braces 3 on the outer side of the two supporting layers, away from the supporting purlin 1, correspond to the positions of the inner supporting purlin 1 of the retaining pile 4.

[0046] In a preferred embodiment, the support body 2 includes: a precast concrete support 21, a support steel frame 22, an axial force jack 23, a force-holding box 24, and a first concrete 25.

[0047] The precast concrete support 21 is pre-cast onto the excavated soil in the foundation pit after the pit is excavated in layers. Multiple lattice columns are installed in the soil within the foundation pit. The precast concrete support 21 is supported within the foundation pit 5 by the lattice columns.

[0048] In this embodiment, a precast concrete support is provided with two supporting steel frames 22. One end of the supporting steel frame 22 is connected to the load-bearing purlin 1. The other end of the supporting steel frame 22 is positioned opposite the end face of the precast concrete support 21. The two supporting steel frames 22 are located on opposite sides of the end face of the precast concrete support 21. The other end of the two supporting steel frames 22 is connected to a first bearing member 26. A second bearing member 27 is connected to the end face. An axial force jack 23 is supported between the first bearing member 26 and the second bearing member 27. A force-holding box 24 is placed between the first bearing member 26 and the second bearing member 27.

[0049] The first concrete 25 encapsulates the two supporting steel frames 22, the axial force jack 23, the force-holding box 24, the first pressure-bearing component 26, and the second pressure-bearing component 27.

[0050] See Figures 2 to 4 The load-bearing purlin 1 includes: connecting steel frame 11, steel reinforcement structure and second concrete 13.

[0051] The connecting steel frame 11 is connected to multiple retaining piles 4. One end of each of the two supporting steel frames 22 of the supporting body 2 is connected to the connecting steel frame 11. The reinforcing steel structure is fitted over the connecting steel frame 11. The second concrete 13 covers the connecting steel frame 11 and the reinforcing steel structure.

[0052] In a preferred embodiment, the reinforcing structure of the load-bearing purlin includes multiple main bars and U-shaped stirrups. The multiple main bars are arranged in a ring around the outside of the connecting steel frame. The U-shaped stirrups are fitted around the outside of the multiple main bars.

[0053] Each support is connected to the retaining pile 4 by two diagonal braces 3. The other end of one diagonal brace 3 is connected to the connecting steel frame 11. The other end of the other diagonal brace 3 is connected to the steel reinforcement structure. The other ends of the two diagonal braces 3 are embedded in the second concrete 13.

[0054] In this embodiment, one end of the diagonal brace is connected to the vertical main reinforcement of the retaining pile, and the other end of the diagonal brace is connected to the steel reinforcement structure of the load-bearing purlin or the connecting steel frame.

[0055] For details, please refer to Figure 5 As shown, one end of the outer diagonal brace of each load-bearing purlin (near the junction of the retaining pile and the load-bearing purlin) is connected to the vertical main reinforcement of the retaining pile, and the other end of the diagonal brace is connected to the steel reinforcement structure of the load-bearing purlin. One end of the inner diagonal brace of each load-bearing purlin is connected to the vertical main reinforcement of the retaining pile, and the other end of the diagonal brace is connected to the connecting steel frame of the load-bearing purlin.

[0056] In this embodiment, the connecting steel frame and the supporting steel frame are H-beams.

[0057] Preferably, the inclination angle of the diagonal brace 3 is 45°.

[0058] See Figure 6 As shown, a lattice column 28 is inserted between the two supporting steel frames 22. The first section of the lattice column is covered with concrete.

[0059] This invention provides a construction method based on a prestressed steel-reinforced concrete asymmetric support structure, comprising the following steps:

[0060] S1: Construction water-stop curtain, with a ring of water-stop curtain set around the perimeter of foundation pit 5.

[0061] Before commencing work, a detailed survey of the pipelines around the foundation pit was conducted, and a thorough understanding of the foundations of nearby buildings (specific form and location of the foundations), the foundation pit, and the slope conditions was obtained.

[0062] The surface of the foundation pit is initially excavated and the site is leveled, while dewatering is carried out. During the excavation, the excavation is carried out in at least three layers, and after each layer is completed, steel support columns are erected on both sides.

[0063] A steel structure was used to form the support, and the construction of the water-stop curtain began simultaneously. After the steel reinforcement cage was placed, concrete was poured directly. A 700mm thick TRD was used as the water-stop curtain, and a drainage ditch was built at the top.

[0064] S2: Cast multiple retaining piles 4 inside the water-stop curtain, so that the multiple retaining piles 4 are arranged in a circle along the circumference of the foundation pit 5.

[0065] Specifically, after the construction of the retaining piles and steel walers begins, concrete is poured to fill the gaps.

[0066] S3: The excavation of the foundation pit 5 is carried out in layers. After each layer of excavation, load-bearing purlins 1 are installed on the inner and outer sides of multiple retaining piles 4. Multiple support bodies 2 are connected to the load-bearing purlins 1. The multiple support bodies 2 are spaced apart along the length of the purlins. The multiple support bodies 2 on the outer side of the retaining piles 4 and the multiple support bodies 2 on the inner side of the retaining piles 4 are alternately arranged. The support bodies 2 on the inner and outer sides of the retaining piles 4 are arranged in the same direction. Multiple diagonal braces 3 are connected between the upper part of the load-bearing purlins 1 of the upper support and the retaining piles 4. Multiple diagonal braces 3 are connected between the lower part of the load-bearing purlins 1 of the lower support and the retaining piles 4. This makes the position of the diagonal braces 3 of the two layers of support on the outer side of the retaining piles 4 away from the load-bearing purlins 1 correspond to the position of the load-bearing purlins 1 on the inner side of the retaining piles 4 to form an asymmetric support structure based on prestressed steel-reinforced concrete.

[0067] When pouring the load-bearing purlins, use U-shaped stirrups to weld and fix them to the steel frame, and connect the reinforcing steel cage. At the same time, pay attention to the setting position of the lattice column. By adding two layers of support on the outside of the retaining piles (the side adjacent to the surrounding building structure), an asymmetric internal support system is formed with the two layers of support on the inside of the retaining piles.

[0068] The second type of concrete is C30 high-strength dense concrete.

[0069] During the pouring of the support, the support body is formed by the use of the retaining box, axial jack, first bearing component, and second bearing component, and then connected to the precast concrete support, which is then connected to the load-bearing purlins and retaining piles.

[0070] The present invention relates to an asymmetric support structure based on prestressed steel-reinforced concrete. Two layers of support are installed on both the inner and outer sides of the retaining piles adjacent to existing building structures. The two layers of support on each side of the retaining pile are spaced apart along the axial direction of the pile. The two layers of support on the outer side of the retaining pile are positioned between the two layers of support on the inner side. Multiple support bodies on the outer side of the retaining pile are alternately arranged with multiple support bodies on the inner side. The support bodies on both the inner and outer sides of the retaining pile are arranged in the same direction. Multiple diagonal braces connect the upper part of the load-bearing purlin of the upper support to the retaining pile, and multiple diagonal braces connect the lower part of the load-bearing purlin of the lower support to the retaining pile. The position of the diagonal braces on the outer side of the two layers of support, away from the load-bearing purlin, corresponds to the position of the load-bearing purlin on the inner side of the retaining pile, forming an asymmetric support structure. This structure effectively controls the deformation of deep foundation pits and protects the safety of surrounding buildings, roads, and underground pipelines.

[0071] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A prestressed ferroconcrete asymmetric braced structure, characterized by, The support includes the inner and outer sides of multiple retaining piles installed in the foundation pit. Two layers of support are provided on both the inner and outer sides of each retaining pile. The two layers of support on each side of the retaining pile are spaced apart along the axial direction of the retaining pile. The two layers of support on the outer side of the retaining pile are positioned between the two layers of support on the inner side of the retaining pile. Each layer of support includes: Load-bearing purlins are installed on multiple of the aforementioned retaining piles; Multiple support bodies are connected to the load-bearing purlin. The multiple support bodies are spaced apart along the length of the load-bearing purlin. The multiple support bodies on the outer side of the retaining pile and the multiple support bodies on the inner side of the retaining pile are alternately arranged. The support bodies on the inner and outer sides of the retaining pile are arranged in the same direction. The upper part of the upper supporting purlin is connected to the retaining pile by multiple diagonal braces, and the lower part of the lower supporting purlin is connected to the retaining pile by multiple diagonal braces. The position of the end of the diagonal brace of the two outer supporting layers of the retaining pile away from the supporting purlin corresponds to the position of the supporting purlin on the inner side of the retaining pile. The support body includes: a precast concrete support, erected in the foundation pit by lattice columns; two supporting steel frames, one end of which is connected to the load-bearing purlin, and the other end of which is opposite to the end face of the precast concrete support, the two supporting steel frames being arranged on opposite sides of the end face of the precast concrete support, the other end of which is connected to a first pressure-bearing member, and the end face being connected to a second pressure-bearing member; an axial force jack, supporting between the first pressure-bearing member and the second pressure-bearing member; a pressure-holding box, placed between the first pressure-bearing member and the second pressure-bearing member; and a first concrete layer covering the two supporting steel frames, the axial force jack, the pressure-holding box, the first pressure-bearing member, and the second pressure-bearing member.

2. The prestressed ferroconcrete asymmetric braced structure according to claim 1, characterized in that, The load-bearing purlins include: The connecting steel frame is connected to multiple retaining piles, and one end of each of the two supporting steel frames of the supporting body is connected to the connecting steel frame; A steel reinforcement structure is fitted over the outside of the connecting steel frame; The second concrete is used to encapsulate the connecting steel frame and the reinforcing steel structure.

3. The prestressed ferroconcrete asymmetric braced structure according to claim 2, characterized in that, Each of the supports is connected to the retaining pile by two diagonal braces. The other end of one diagonal brace is connected to the connecting steel frame, and the other end of the other diagonal brace is connected to the steel reinforcement structure. The other ends of the two diagonal braces are embedded in the second concrete.

4. The prestressed ferroconcrete asymmetric braced structure according to claim 2, characterized in that, The angle of inclination of the diagonal brace is 45°.

5. The prestressed ferroconcrete asymmetric braced structure according to claim 1, characterized in that, A lattice column is inserted between the two supporting steel frames.

6. A construction method of a prestressed ferroconcrete asymmetric braced structure according to any one of claims 1 to 5, characterized in that, Includes the following steps: A construction water-stop curtain is provided, which is set in a circle around the perimeter of the foundation pit; Multiple retaining piles are poured inside the water-stop curtain, so that the multiple retaining piles are arranged in a circle along the circumferential direction of the foundation pit. The excavation of the foundation pit is carried out in layers. After each layer of excavation, load-bearing purlins are installed on both the inner and outer sides of multiple retaining piles. Multiple support bodies are connected to the load-bearing purlins. The multiple support bodies are spaced apart along the length of the purlins. The multiple support bodies on the outer side of the retaining piles are alternately arranged with the multiple support bodies on the inner side of the retaining piles. The support bodies on the inner and outer sides of the retaining piles are arranged in the same direction. Multiple diagonal braces are connected between the upper part of the load-bearing purlins of the upper layer of support and the retaining piles. Multiple diagonal braces are connected between the lower part of the load-bearing purlins of the lower layer of support and the retaining piles. The position of the diagonal braces of the two layers of support on the outer side of the retaining piles, away from the load-bearing purlins, corresponds to the position of the load-bearing purlins on the inner side of the retaining piles, thus forming an asymmetric support structure based on prestressed steel-reinforced concrete.

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