Soil protection structure between cast-in-place piles in a foundation pit support structure

Abstract

The embodiment of the present application provides a soil protection structure between bored piles of a foundation pit support structure, comprising: a plurality of grid frames, each of which is arranged in layers from top to bottom, and the two ends of the grid frames are respectively used to be fixedly connected to two adjacent bored piles; a plurality of connecting ribs, each of which is arranged in vertical intervals, and the connecting ribs are fixedly connected to each of the grid frames; wherein the grid frames and the connecting ribs fixed as a whole are used to reinforce the soil between the bored piles to prevent the soil between the bored piles from slipping. The embodiment of the present application solves the technical problem that the soil protection measures of the existing soil protection surface layer cannot be applied to situations where the spacing between bored piles is large.

Description

Technical Field

[0001] The present application relates to the technical field of foundation pit construction of construction projects, and in particular to a soil protection structure between cast-in-place piles of a foundation pit support structure. Background Art

[0002] In the foundation pit projects of urban rail transit and industrial and civil buildings, foundation pit support structures are used to protect the soil of the foundation pit. The foundation pit support structure includes at least a number of bored piles set at intervals. Normally, the soil protection surface layer between bored piles is composed of steel mesh, hanging mesh steel bars, transverse reinforcing steel bars, soil steel nails between piles and sprayed concrete surface layer. The thickness of the concrete surface layer is generally 50 to 100 mm, and the strength grade of the sprayed concrete is C20. The soil protection measure of setting a soil protection surface layer between the above-mentioned bored piles is only applicable to the general conditions where the spacing between bored piles is less than 2 times the diameter of the bored piles. In special circumstances, due to limited conditions, when the spacing between bored piles is large, the above-mentioned measure of setting a soil protection surface layer between bored piles will have insufficient strength and difficulty in protecting the soil between the bored piles. Excessive soil pressure will cause the protection surface layer to crack and fail, posing a safety hazard.

[0003] Therefore, the existing soil protection measures for the soil protection surface layer cannot be applied to situations where the spacing between cast-in-place piles is large, which is a technical problem that technical personnel in this field urgently need to solve.

[0004] The above information disclosed in the Background section is only for enhancement of understanding of the background of the application and therefore it may contain information that does not form the prior art known to a person of ordinary skill in the art. Summary of the Invention

[0005] An embodiment of the present application provides a soil protection structure between bored piles of a foundation pit support structure to solve the technical problem that the soil protection measures of the existing soil protection surface layer cannot be applied to situations where the spacing between bored piles is large.

[0006] The present application provides a soil protection structure between cast-in-place piles of a foundation pit support structure, comprising:

[0007] A plurality of grid frames, each of which is layered and spaced from top to bottom, and each end of the grid frame is used to be fixedly connected to two adjacent cast-in-place piles;

[0008] A plurality of connecting ribs, each of which is vertically spaced apart and fixedly connected to each of the grid frames;

[0009] The grid frame and the connecting ribs fixed as one are used to reinforce the soil between the bored piles to prevent the soil between the bored piles from slipping.

[0010] The embodiments of the present application adopt the above technical solutions, which have the following technical effects:

[0011] After the cast-in-place piles of the foundation pit support structure are cast and reach strength, the foundation pit is excavated. As the foundation pit is excavated from top to bottom, the grid frames are sequentially spaced apart in layers from top to bottom, with each end of the grid frame fixedly connected to two adjacent cast-in-place piles. After the grid frames are installed, the connecting bars are vertically spaced apart, and each connecting bar is fixedly connected to each grid frame from top to bottom. In this way, the grid frames and connecting bars are fixed together, reinforcing the soil between the cast-in-place piles and preventing the soil from slipping between the cast-in-place piles. The soil protection structure between the cast-in-place piles of the foundation pit support structure of the present embodiment of the application reinforces the soil between the cast-in-place piles by fixing the horizontally arranged grid frames and the vertically arranged connecting bars together. The strength of the soil protection structure can be controlled based on the strength and installation density of the grid frames and the strength and installation density of the connecting bars. Therefore, it is suitable for situations where the spacing between cast-in-place piles is large, and is particularly suitable for situations where the spacing between cast-in-place piles is greater than twice the diameter of the cast-in-place piles. At the same time, the horizontally arranged grid frame and the vertically arranged connecting ribs are fixed as a whole, which makes construction convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0013] Figure 1 A planar cross-sectional view of the soil protection structure between the cast-in-place piles of the foundation pit support structure according to an embodiment of the present application at any height of the cast-in-place piles;

[0014] Figure 2 This is a vertical cross-sectional view of the soil protection structure between the cast-in-place piles of the foundation pit support structure according to an embodiment of the present application;

[0015] Figure 3 A schematic diagram of a grid frame of a soil protection structure according to an embodiment of the present application;

[0016] Figure 4 A schematic diagram of another position of the grid frame of the soil protection structure according to an embodiment of the present application;

[0017] Figure 5 This is a schematic end view of the grid frame of the soil protection structure of an embodiment of the present application.

[0018] Description of reference numerals:

[0019] 100 grid frame, 111 grid main reinforcement, 112 Z-shaped connecting reinforcement, 113 U-shaped connecting reinforcement,

[0020] 114 grid stirrups, 120 connectors,

[0021] 200 connecting ribs, 211 inner layer connecting ribs, 212 middle layer connecting ribs, 213 outer layer connecting ribs,

[0022] 300 grouting anchor pipe, 410 steel mesh,

[0023] 11 cast-in-place piles, 12 pile top beams, 20 foundation pits. DETAILED DESCRIPTION

[0024] In order to make the technical solutions and advantages of the embodiments of the present application more clearly understood, the exemplary embodiments of the present application are further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, and are not an exhaustive list of all the embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other unless there is a conflict.

[0025] The soil protection structure between the bored piles of the foundation pit support structure in the embodiment of the present application relates to the technical field of foundation pit construction of construction projects, and is applicable to situations in which the spacing between bored piles is large in the field of urban rail transit projects and industrial and civil construction projects, and is particularly applicable to situations in which the spacing between bored piles is greater than 2 times the diameter of the bored piles.

[0026] Example 1

[0027] Figure 1 A planar cross-sectional view of the soil protection structure between the cast-in-place piles of the foundation pit support structure according to an embodiment of the present application at any height of the cast-in-place piles; Figure 2 This is a vertical cross-sectional view of the soil protection structure between the cast-in-place piles of the foundation pit support structure of an embodiment of the present application.

[0028] like Figure 1 and Figure 2 As shown, the soil protection structure between the cast-in-place piles of the foundation pit support structure of the embodiment of the present application includes:

[0029] A plurality of grid frames 100, each of which is layered and spaced from top to bottom, and each end of the grid frame 100 is used to be fixedly connected to two adjacent cast-in-place piles 11;

[0030] A plurality of connecting ribs 200, each of the connecting ribs 200 is vertically spaced apart and fixedly connected to each of the grid frames 100;

[0031] The grid frame 100 and the connecting ribs 200 fixed together are used to reinforce the soil between the bored piles to prevent the soil between the bored piles from slipping.

[0032] After the cast-in-place piles of the foundation pit support structure are cast and reach strength, the foundation pit is excavated. As the foundation pit is excavated from top to bottom, the grid frames are sequentially spaced apart in layers from top to bottom, with each end of the grid frame fixedly connected to two adjacent cast-in-place piles. After the grid frames are installed, the connecting bars are vertically spaced apart, and each connecting bar is fixedly connected to each grid frame from top to bottom. In this way, the grid frames and connecting bars are fixed together, reinforcing the soil between the cast-in-place piles and preventing the soil from slipping between the cast-in-place piles. The soil protection structure between the cast-in-place piles of the foundation pit support structure of the present embodiment of the application reinforces the soil between the cast-in-place piles by fixing the horizontally arranged grid frames and the vertically arranged connecting bars together. The strength of the soil protection structure can be controlled based on the strength and installation density of the grid frames and the strength and installation density of the connecting bars. Therefore, it is suitable for situations where the spacing between cast-in-place piles is large, and is particularly suitable for situations where the spacing between cast-in-place piles is greater than twice the diameter of the cast-in-place piles. At the same time, the horizontally arranged grid frame and the vertically arranged connecting ribs are fixed as a whole, which makes construction convenient.

[0033] Specifically, the grid frame adopts a steel structure grid frame, and the connecting ribs are steel structure connecting ribs.

[0034] The grid frame is fixedly connected to the main reinforcement of the cast-in-place pile by single-sided welding, and the grid frame is fixedly connected to the connecting reinforcement by welding.

[0035] Specifically, the strength and setting density of the grid frame and the strength and setting density of the connecting reinforcement are selected according to the self-stability of the soil between the cast-in-place piles, so that the strength of the soil protection structure meets the requirements.

[0036] In practice, the vertical spacing between adjacent grid frames ranges from greater than or equal to 0.5 meters to less than or equal to 0.75 meters.

[0037] The grid frame setting density is selected based on the self-stability of the soil between the cast-in-place piles. The smaller the vertical spacing of the grid frames, the greater the grid frame setting density.

[0038] In implementation, such as Figure 1 As shown, the inner edge of the grid frame 100 is outward relative to the inner edge of the cast-in-place pile 11; or the inner edge of the grid frame is flush with the inner edge of the cast-in-place pile;

[0039] The inner edge of the grid frame is the edge of the grid frame close to the foundation pit surrounded by the cast-in-place piles, and the inner edge of the cast-in-place piles is the edge of the cast-in-place piles facing the foundation pit.

[0040] In the embodiment of the present application, the directions of inside and outside are specified, where inside refers to the side facing the foundation pit, and outside refers to the side away from the foundation pit. The location of the cast-in-place piles is determined by the foundation pit. After the location and shape of the foundation pit are determined, cast-in-place piles are arranged at intervals along the periphery of the foundation pit, that is, each cast-in-place pile surrounds the periphery of the foundation pit. The position of the grid frame is set so that the inner edge of the grid frame is outward relative to the inner edge of the cast-in-place pile; or the inner edge of the grid frame is flush with the inner edge of the cast-in-place pile. In this way, the location and manner of setting the grid frame have no additional impact on the cast-in-place piles and the foundation pit.

[0041] The setting of connecting ribs has the following characteristics.

[0042] In implementation, such as Figure 2 As shown, the upper end of the connecting bar 200 is anchored and fixed in the pile top crown beam 12 of the foundation pit supporting structure;

[0043] The pile top crown beam 12 is a structure fixed on the top of the cast-in-place pile to fix multiple cast-in-place piles into one.

[0044] The foundation pit support structure includes not only multiple cast-in-place piles spaced apart but also pile cap beams. These cap beams are fixed to the tops of the cast-in-place beams, connecting the piles and thus securing the piles together. The top ends of the connecting bars are secured within the pile cap beams, vertically securing the beams and making the structure, which combines the horizontally arranged grids and vertically arranged connecting bars, more stable.

[0045] In implementation, such as Figure 1 As shown, the connecting ribs are arranged in layers, including inner layer connecting ribs 211 and middle layer connecting ribs 212;

[0046] The inner layer connecting ribs 211 are arranged on the side of the inner main ribs of the grid frame facing the foundation pit 20, and the middle layer connecting ribs 212 are arranged on the side of the inner main ribs of the grid frame facing away from the foundation pit 20. The inner main ribs of the grid frame 100 are the main ribs of the grid frame close to the foundation pit.

[0047] The spacing between the inner layer connecting ribs 211 is smaller than the spacing between the middle layer connecting ribs 212 .

[0048] The soil protection structure prevents soil between the piles from sliding into the foundation pit. The spacing between the inner connecting bars is smaller than the spacing between the middle connecting bars. This means that the spacing and density of the inner connecting bars are closer to the foundation pit, which helps prevent soil between the piles from sliding into the foundation pit.

[0049] In implementation, such as Figure 1As shown, the inner layer connecting ribs 211 and the middle layer connecting ribs 212 are staggered.

[0050] Each connecting bar is continuous in the vertical direction, and in the horizontal plane, the inner layer connecting bars and the middle layer connecting bars are staggered. In this way, the soil between the cast-in-place piles is evenly reinforced in multiple directions and positions.

[0051] In implementation, such as Figure 1 As shown, the connecting ribs further include outer connecting ribs 213, which are arranged on the side of the outer main ribs of the grid frame 100 facing the foundation pit;

[0052] The spacing between the outer layer connecting ribs 213 is equal to the spacing between the middle layer connecting ribs 212;

[0053] The outer main reinforcement of the grid frame is the main reinforcement in the center of the grid frame that is parallel to the inner main reinforcement of the grid frame and away from the foundation pit.

[0054] The three-layer arrangement of the inner connecting reinforcement, the middle connecting reinforcement and the outer connecting reinforcement makes the reinforcement and protection of the soil between the bored piles multi-layered, which can better prevent the soil from sliding.

[0055] In implementation, such as Figure 1 As shown, the outer layer connecting ribs 213 and the middle layer connecting ribs 212 are arranged opposite to each other; or the outer layer connecting ribs and the middle layer connecting ribs are arranged in a staggered manner.

[0056] In this way, the relative arrangement and staggered arrangement of the outer layer connecting ribs and the middle layer connecting ribs can be selected according to the structure of the grid frame and the convenience of construction.

[0057] Specifically, the distance between the inner connecting ribs and the outer connecting ribs is determined by the size of the grid frame.

[0058] The size of the grid is selected based on the self-stability of the soil between the cast-in-place piles, for example, so that the spacing between the inner and outer connecting bars is 1 meter.

[0059] In order to further strengthen the soil between the cast-in-place piles.

[0060] In implementation, such as Figure 1 As shown, the soil protection structure also includes:

[0061] Multiple layers of grouting anchor pipes 300, each layer of grouting anchor pipes 300 is spaced apart from top to bottom, and each grouting anchor pipe of each layer of grouting anchor pipes 300 is spaced apart from each other, and each grouting anchor pipe 300 extends from between the grid frames and from the inner wall of the foundation pit 20 into the soil between the cast-in-place piles 11;

[0062] The grouting anchor pipe 300 is used to inject grout from the inner wall of the foundation pit 20 into the soil between the cast-in-place piles 11 to fix the soil.

[0063] The presence of grouting anchor pipes makes it possible to inject grout into the soil between the bored piles from the inner wall of the foundation pit. After grouting, the soil between the bored piles is reinforced, thereby better reinforcing the soil between the bored piles and achieving better protection.

[0064] In implementation, such as Figure 2 As shown, the vertical spacing between adjacent layers of grouting anchor pipes 300 is equal to the vertical spacing between adjacent layers of grid frames 100, and a layer of grouting anchor pipes 300 is provided under each layer of grid frames 100;

[0065] The two adjacent layers of grouting anchor pipes 300 are staggered, and the two layers of grouting anchor pipes 300 in every other layer are arranged opposite to each other.

[0066] The grouting anchor pipes are dispersedly arranged, roughly in the shape of a plum blossom, so that the soil between the bored piles is evenly reinforced and the chance of soil slipping between the bored piles is reduced.

[0067] In implementation, the length of each grouting anchor pipe ranges from greater than or equal to 2 meters to less than or equal to 3.5 meters;

[0068] The spacing between adjacent grouting anchor pipes in each layer of grouting anchor pipes ranges from greater than or equal to 0.5 meters to less than or equal to 1.5 meters.

[0069] The length of the grouting anchor pipe and the spacing between adjacent grouting anchor pipes in each layer of grouting anchor pipes can be selected according to actual conditions.

[0070] Specifically, the length of each grouting anchor pipe is 3 meters; the spacing between adjacent grouting anchor pipes in each layer of grouting anchor pipes is 1 meter.

[0071] In implementation, such as Figure 2 As shown, the soil protection structure also includes:

[0072] Steel mesh 410 is hung from top to bottom on the inner edge of each grid frame 100;

[0073] The concrete surface layer is formed at the steel mesh 410 .

[0074] The steel mesh is set up in a manner that the steel mesh is hung from top to bottom on the inner edge of the grid steel frame, and the concrete surface layer is formed by spraying concrete to form the concrete surface layer.

[0075] About the structure of the grid. Figure 3 A schematic diagram of a grid frame of a soil protection structure according to an embodiment of the present application; Figure 4A schematic diagram of another position of the grid frame of the soil protection structure according to an embodiment of the present application; Figure 5 This is a schematic end view of the grid frame of the soil protection structure of an embodiment of the present application.

[0076] In implementation, such as Figure 3 , Figure 4 and Figure 5 As shown, the grid frame includes a plurality of grids and a connecting member 120, and each grid is connected to form a grid frame through the connecting member 120; the grid includes:

[0077] Four main grille ribs 111, wherein the four main grille ribs are located at four vertices of the same rectangular frame;

[0078] Z-shaped connecting ribs 112 and U-shaped connecting ribs 113, the upper and lower sides of the Z-shaped connecting ribs 112 are respectively fixed to two adjacent grille main ribs, and the two side arms of the U-shaped connecting ribs 113 are respectively fixed to two adjacent grille main ribs. The Z-shaped connecting ribs 112 and the U-shaped connecting ribs 113 connect the four grille main ribs 111 to form a rectangular frame;

[0079] Grille stirrups 114, the grille stirrups 114 are hooped on the outside of the grille main reinforcement;

[0080] Wherein, the main ribs of the grid serve as the main ribs of the grid frame.

[0081] The grid frame of the above structure has a simple structure and high strength, and is suitable for use as a grid frame for soil protection structures.

[0082] The soil protection structure between the cast-in-place piles of the entire foundation pit support structure is constructed as the earthwork is excavated, and the entire soil protection structure is completed when the foundation pit is excavated to the bottom. Because the soil pressure between the cast-in-place piles is transmitted to the grid frame, and then transmitted to the cast-in-place piles on both sides through the grid frame, special measures should be taken for the cast-in-place piles on both sides, such as increasing the pile diameter and reinforcement ratio, and appropriately increasing the spacing between adjacent cast-in-place piles or increasing the pile diameter and reinforcement ratio.

[0083] The structural form of the soil protection structure between the cast-in-place piles of the foundation pit support structure in the embodiment of the present application can be applied to the soil protection needs when the spacing between the cast-in-place piles is large under special conditions, and can effectively resist the surrounding soil pressure to ensure the safety of the foundation pit; it has the advantages of clear force transmission path, convenient operation, high structural rigidity and strength, easy processing, safety and reliability.

[0084] In the description of the present application and its embodiments, it should be understood that the terms "top", "bottom", "height", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present application.

[0085] In this application and its embodiments, unless otherwise expressly specified or limited, terms such as "disposed," "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections, electrical connections, or communication; direct connections or indirect connections through an intermediate medium; and internal connections between two components or interactions between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0086] In the present application and its embodiments, unless otherwise expressly specified and limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0087] The disclosure above provides many different embodiments or examples for realizing the different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described above. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numerals and / or reference letters in different examples, and such repetition is for the purpose of simplicity and clarity, and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0088] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0089] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A soil protection structure between cast-in-place piles of a foundation pit support structure, characterized in that: include: A plurality of grid frames, each of which is arranged in layers and intervals from top to bottom, and two ends of each grid frame are respectively used to be fixedly connected to two adjacent cast-in-place piles; A plurality of connecting ribs, each of which is vertically spaced and fixedly connected to each of the grid frames; The grid frame and the connecting ribs fixed as one are used to reinforce the soil between the cast-in-place piles to prevent the soil between the cast-in-place piles from slipping; The connecting ribs are arranged in layers, including inner layer connecting ribs and middle layer connecting ribs; The inner layer connecting ribs are arranged on the side of the inner main ribs of the grid frame facing the foundation pit, the middle layer connecting ribs are arranged on the side of the inner main ribs of the grid frame facing away from the foundation pit, and the inner main ribs of the grid frame are the main ribs of the grid frame close to the foundation pit; Wherein, the spacing between the inner layer connecting ribs is smaller than the spacing between the middle layer connecting ribs; The connecting ribs further include outer connecting ribs, which are arranged on the side of the outer main ribs of the grid frame facing the foundation pit; The spacing between the outer layer connecting ribs is equal to the spacing between the middle layer connecting ribs; The outer main reinforcement of the grid frame is a main reinforcement in the grid frame that is parallel to the inner main reinforcement of the grid frame and is away from the foundation pit; The inner edge of the grid frame is outward relative to the inner edge of the cast-in-place pile; or the inner edge of the grid frame is flush with the inner edge of the cast-in-place pile; Wherein, the inner edge of the grid frame is the edge of the grid frame close to the foundation pit surrounded by the cast-in-place piles, and the inner edge of the cast-in-place piles is the edge of the cast-in-place piles facing the foundation pit; The upper end of the connecting bar is fixed in the pile top crown beam of the foundation pit supporting structure; Wherein, the pile top crown beam is a structure fixed on the top of the cast-in-place pile to fix multiple cast-in-place piles into one; The inner layer connecting ribs and the middle layer connecting ribs are staggered; The outer layer connecting ribs and the middle layer connecting ribs are arranged opposite to each other or staggered; Also includes: Multiple layers of grouting anchor pipes, each layer of grouting anchor pipes is arranged at intervals from top to bottom, each grouting anchor pipe of each layer is arranged at intervals, and each of the grouting anchor pipes extends from between the grid frames and from the inner wall of the foundation pit into the soil between the cast-in-place piles; Wherein, the grouting anchor pipe is used to inject grout from the inner wall of the foundation pit into the soil between the cast-in-place piles to fix the soil; The vertical spacing between adjacent layers of grouting anchor pipes is equal to the vertical spacing between adjacent layers of grid frames, and a layer of grouting anchor pipes is arranged under each layer of grid frames; Two adjacent layers of grouting anchor pipes are staggered, and every other layer of two layers of grouting anchor pipes are arranged opposite to each other; The grid frame adopts a steel structure grid frame, and the connecting ribs are steel structure connecting ribs.

2. The soil protection structure according to claim 1, characterized in that: The vertical spacing between adjacent grid frames ranges from greater than or equal to 0.5 meters to less than or equal to 0.75 meters.

3. The soil protection structure according to claim 2, characterized in that: The length of each grouting anchor pipe is in the range of greater than or equal to 2 meters and less than or equal to 3.5 meters; The spacing between adjacent grouting anchor pipes in each layer of grouting anchor pipes ranges from greater than or equal to 0.5 meters to less than or equal to 1.5 meters.

4. The soil protection structure according to claim 3, characterized in that: Also includes: A steel mesh is hung from top to bottom on the inner edge of each of the grid frames; A concrete surface layer is formed at the steel mesh.

5. The soil protection structure according to claim 4, characterized in that: The grid frame comprises a plurality of grids and connecting members, and each of the grids is connected as a whole through the connecting members to form the grid frame; the grid comprises: Four main grille bars, wherein the four main grille bars are located at four vertices of the same rectangular frame; Z-shaped connecting ribs and U-shaped connecting ribs, the upper side and the lower side of the Z-shaped connecting ribs are respectively fixed to two adjacent grille main ribs, the two side arms of the U-shaped connecting ribs are respectively connected to two adjacent grille main ribs, and the Z-shaped connecting ribs and the U-shaped connecting ribs connect the four grille main ribs to form a rectangular frame; Grille stirrups, the grille stirrups are hooped on the outside of the grille main reinforcement; Wherein, the main grating reinforcement serves as the main reinforcement of the grating frame.

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