A retaining wall in a foundation pit and a construction method thereof

Abstract

The application provides a foundation pit enclosure partition wall and a construction method thereof. The foundation pit enclosure partition wall comprises an SMW method pile, a surrounding purlin, a plurality of front support type inclined support components and a water stop sealing structure. Two front support type inclined supports of each front support type inclined support component are symmetrically arranged relative to the SMW method pile. The water stop sealing structure comprises a soil body reinforcing layer and a grouting water stop layer, which correspond to a section of the front support type inclined support inserted into the soil body and a gap between the front support type inclined support and the soil body, respectively. Compared with a traditional foundation pit enclosure partition wall, the foundation pit enclosure partition wall of the application reduces the occupation of the foundation pit space, has no red line outside occupation, has the advantages of strong synergistic stress, reliable water stop, short construction period and low cost.

Description

Technical Field

[0001] This invention relates to the field of building construction technology, and in particular to a partition wall for foundation pit protection and its construction method. Background Technology

[0002] Currently, there are two main solutions for retaining walls in foundation pits: SMW (Surface Mount Welded Wall) piles and internal bracing systems, and SMW piles and anchor systems. Internal bracing systems occupy internal space within the foundation pit, hindering excavation and main construction. They require layered support replacement, resulting in long construction periods and high costs, and are particularly unsuitable for narrow, elongated foundation pits. Anchor systems, on the other hand, require penetration through the cutoff wall and extension beyond the building boundary, which is prohibited by most city regulations, leading to poor compliance. Furthermore, penetration through the cutoff wall can create leakage channels, compromising the effectiveness of water sealing and posing a high risk in areas with high water levels and soft soil.

[0003] In view of the shortcomings of the partition walls in the existing foundation pit protection technology, those skilled in the art have been looking for solutions. Summary of the Invention

[0004] The purpose of this invention is to provide a partition wall for foundation pit protection and its construction method, which can solve the shortcomings of the existing partition wall for foundation pit protection.

[0005] To solve the above-mentioned technical problems, the present invention provides a partition wall for foundation pit retaining walls, the partition wall for foundation pit retaining walls comprising: an SMW method pile, which is laid out along the design edge line of the partition wall for foundation pit retaining walls;

[0006] A purlin is cast into the top of the SMW method pile;

[0007] Multiple front-supported inclined bracing components, each front-supported inclined bracing component includes two front-supported inclined braces, the two front-supported inclined braces are symmetrically arranged relative to the SMW method pile, the near end of each front-supported inclined brace is connected to the waler, and its far end is inserted obliquely into the foundation pit soil.

[0008] A water-stopping sealing structure includes a soil reinforcement layer and a grouting water-stopping layer, which are respectively formed in the section where the front-supported inclined brace is inserted into the soil and in the gap between the front-supported inclined brace and the soil.

[0009] Optionally, the retaining wall of the foundation pit also includes: a rigid connection embedded part, which is embedded in the waler at the top of the SMW method pile and extends out of the waler at both ends.

[0010] Optionally, in the partition wall of the foundation pit retaining structure, the proximal ends of the two front-supported diagonal braces in each front-supported diagonal brace assembly are respectively connected to the opposite ends of the same rigid connection embedded part.

[0011] Optionally, in the partition wall of the foundation pit retaining structure, the SMW method pile includes multiple triaxial cement-soil mixing piles and multiple steel sections. The pile bodies of adjacent triaxial cement-soil mixing piles are interlocked and overlapped. The multiple steel sections are inserted longitudinally into the pile body of the corresponding triaxial cement-soil mixing pile at predetermined intervals.

[0012] Optionally, in the partition wall of the foundation pit retaining structure, the upper end of the steel section extends beyond the top of the pile body of the three-axis cement-soil mixing pile into which it is inserted, and is higher than the top surface of the waler.

[0013] Optionally, in the partition wall of the foundation pit retaining structure, the paired front-supported diagonal braces are arranged in a figure-eight shape, with the horizontal angle between the two front-supported diagonal braces ranging from 30° to 60°, and the vertical inclination angle between each front-supported diagonal brace and the horizontal plane ranging from 15° to 45°.

[0014] This invention also provides a construction method for a partition wall in the foundation pit retaining structure, the construction method of which includes:

[0015] S1: Construction preparation;

[0016] S2: SMW method piles are constructed by laying out the partition wall in the foundation pit along the designed edge line of the foundation pit.

[0017] S3: A waler is formed by pouring concrete on top of the SMW method pile;

[0018] S4: Carry out the construction and installation of multiple front-supported inclined bracing components so that two front-supported inclined braces in each front-supported inclined bracing component are symmetrically arranged relative to the SMW method pile, and the near end of each front-supported inclined brace is connected to the waler, and its far end is inserted obliquely into the foundation pit soil.

[0019] S5: Perform water-stop sealing treatment on the sections where the front-supported diagonal bracing is inserted into the soil and at the joints between the front-supported diagonal bracing and the soil.

[0020] S6: Conduct acceptance testing and construction.

[0021] Optionally, in the construction method of the partition wall in the foundation pit retaining structure, when performing S3, the following steps are included:

[0022] Tie waler reinforcement bars at the top of the SMW method piles;

[0023] According to the installation points of the front-supported diagonal bracing components, rigid connection embedded parts are pre-embedded simultaneously; after acceptance, concrete is poured to complete the waler construction.

[0024] Optionally, in the construction method of the partition wall in the foundation pit retaining structure, when performing S4, the following steps are included:

[0025] After the waler concrete reaches its design strength, install the front-supported diagonal bracing components according to the design intervals; the process of installing the paired front-supported diagonal bracing is as follows:

[0026] Weld the proximal ends of the two front-bracing diagonal braces to the opposite ends of the same rigid connection embedded part;

[0027] The far ends of the two root-supported diagonal braces are pushed obliquely into the soil of the foundation pit at the designed depth.

[0028] Optionally, in the construction method of the partition wall in the foundation pit retaining structure, when performing S5, the following steps are included:

[0029] Pre-grouting reinforcement is carried out on the sections where the front-supported inclined bracing is inserted into the soil to form a soil reinforcement layer;

[0030] High-pressure grouting is used to fill the gap between the front-supported diagonal brace and the soil to form a grouting water-stopping layer.

[0031] The partition wall and its construction method for foundation pit support provided by this invention have the following beneficial effects:

[0032] 1) Significantly improved construction efficiency: The layout of the front-supported inclined bracing components reduces the space occupied inside the foundation pit, eliminates the need for bracing replacement, and ensures almost no obstacles during earthwork excavation and main construction. The construction period is shortened by more than 30% compared to the traditional internal support system.

[0033] 2) Excellent retaining structure stability: Based on the waler, the front-supported inclined bracing components are connected with the SMW method piles to form an integrated and coordinated force-bearing system. The two front-supported inclined bracing components in each front-supported inclined bracing component are symmetrically distributed relative to the SMW method piles, which can effectively limit the lateral displacement of the pile body. The anti-overturning and anti-torsion performance is outstanding, and the deformation of the retaining structure is reduced by more than 40% compared with the traditional scheme.

[0034] 3) Reliable water-stopping performance: Water-stopping and sealing are carried out based on the water-stopping and sealing structure, without the need to penetrate the water-stopping curtain, eliminating leakage channels and meeting the water-stopping requirements of foundation pits in soft soil areas with high water levels.

[0035] 4) Excellent economic and environmental performance: Both the front-supported inclined bracing and the SMW method piles are recyclable, reducing the overall cost by more than 20% compared to traditional solutions. There is no construction waste, which meets the requirements of green construction. Attached Figure Description

[0036] The above and other objects, features and advantages of this disclosure will become more apparent from the accompanying drawings, in which like reference numerals generally denote like parts.

[0037] Figure 1This is a top view of the partition wall in the foundation pit enclosure according to one embodiment of the present invention;

[0038] Figure 2 This is a front view of the partition wall in the foundation pit enclosure according to one embodiment of the present invention;

[0039] Figure 3 This is a side view of the partition wall in the foundation pit enclosure according to one embodiment of the present invention.

[0040] In the picture:

[0041] 100-SMW method pile; 1-Triaxial cement-soil mixing pile; 2-Steel section; 3-Wallet; 4-Front-supported inclined brace; 5-Soil reinforcement layer; 6-Grouting and water-stopping layer; 7-Bottom slab cushion layer. Detailed Implementation

[0042] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed account of the partition wall and its construction method for the foundation pit retaining structure proposed in this invention. The advantages and features of this invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of this invention.

[0043] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0044] In the description of the invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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. Therefore, they should not be construed as limitations on the invention.

[0045] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0046] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0047] Please refer to Figures 1 to 3 The retaining wall of the foundation pit includes: a SMW method pile 100, a waler 3, multiple front-supported inclined bracing components, and a water-stop sealing structure. The SMW method pile 100 is arranged along the design edge of the retaining wall of the foundation pit. The waler 3 is cast and formed on the top of the SMW method pile 100. Each front-supported inclined bracing component includes two front-supported inclined braces, which are symmetrically arranged relative to the SMW method pile 100. The near end of each front-supported inclined brace is connected to the waler 3, and its far end is inserted obliquely into the foundation pit soil. The water-stop sealing structure includes a soil reinforcement layer 5 and a grouting water-stopping layer 6, which are respectively formed in the section where the front-supported inclined brace is inserted into the soil and in the gap between the front-supported inclined brace and the soil.

[0048] It is understood that the predetermined interval is the spacing between adjacent steel sections 2. The specific value of the predetermined interval should be determined according to the engineering design requirements, and on-site construction should be carried out according to this spacing.

[0049] For a better option, please refer to the following. Figure 3 The paired front-supporting diagonal braces are arranged in a figure-eight pattern. Specifically, the horizontal angle between the two front-supporting diagonal braces ranges from 30° to 60°, and the vertical angle between each front-supporting diagonal brace 4 and the horizontal plane ranges from 15° to 45°. This angled arrangement of the front-supporting diagonal braces effectively limits the lateral displacement of the pile, resulting in outstanding anti-overturning and anti-torsional performance, and reducing the deformation of the retaining structure by more than 40% compared to traditional methods. Furthermore, the partition wall in the foundation pit retaining structure also includes rigid connection embedded parts, pre-embedded in the waler 3 at the top of the SMW method pile 100, with opposite ends extending beyond the waler 3. The proximal ends of the two front-supporting diagonal braces in each front-supporting diagonal brace assembly are respectively connected to the opposite ends of the same rigid connection embedded part. In other words, the two front-supporting diagonal braces in each front-supporting diagonal brace assembly are rigidly connected to the waler 3 based on the rigid connection embedded parts, thereby connecting the front-supporting diagonal brace assembly and the SMW method pile into one unit based on the waler 3, forming an integrated and collaborative force-bearing system, and the front-supporting diagonal brace does not need to penetrate the water-stop curtain.

[0050] Here, the rigid connection embedded parts are pre-embedded simultaneously during the pouring process of forming the waler 3 at the top of the SMW method pile. The rigid connection embedded parts are used to form a reliable force transmission path between the waler 3 and the near end of the front-supported diagonal brace 4, so that the lateral / axial force of the diagonal brace is indirectly transmitted to the top of the waler and the wall of the SMW method pile through the embedded parts, while ensuring the relative positional accuracy and overall rigidity of the front-supported diagonal brace and the waler.

[0051] In this embodiment, as Figure 1 As shown, the SMW method pile includes multiple triaxial cement-soil mixing piles 1 and multiple steel sections 2. The pile bodies of adjacent triaxial cement-soil mixing piles 1 are interlocked to form a continuous impermeable wall, i.e., a continuous water-stop curtain for the foundation pit. The multiple steel sections 2 are inserted longitudinally into the pile body of the corresponding triaxial cement-soil mixing pile 1 at predetermined intervals.

[0052] In this embodiment, preferably, the upper end of the steel section 2 extends beyond the top of the pile body of the triaxial cement-soil mixing pile 1 into which it is inserted, and is higher than the top surface of the waler 3. This arrangement allows the top end of the steel section 2 to be embedded inside the waler 3 to form a rigid anchoring section, thereby achieving coordinated force sharing among the steel section 2, the waler 3, and the triaxial cement-soil mixing pile 1, and reserving clamping allowance for future steel section recycling.

[0053] In this embodiment, the steel section 2 is an H-beam. Correspondingly, this embodiment also provides a construction method for the partition wall in the foundation pit retaining structure. See below for reference. Figures 1 to 3 This embodiment details the construction method of the partition wall in the foundation pit retaining structure.

[0054] First, proceed with step S1, construction preparation.

[0055] The execution of S1 specifically involves: leveling the construction site, completing the survey and layout according to the foundation pit retaining design drawings, accurately locating the placement points of the three-axis cement-soil mixing pile 1, inner steel 2, waler 3 and front-supported diagonal brace 4, ensuring that the plane position and elevation of each component meet the design requirements, and providing a positioning benchmark for subsequent mixing pile construction, steel insertion, waler installation and diagonal brace erection.

[0056] Next, step S2 is executed, and SMW method piles 100 are constructed along the designed edge line of the partition wall in the foundation pit.

[0057] Specifically, the three-axis cement-soil mixing pile 1 is continuously overlapped and laid out along the design edge line of the partition wall in the foundation pit. Steel sections 2 are inserted into the pile body of the three-axis cement-soil mixing pile 1 at the design interval. The two together form SMW method piles to form a continuous water-stop curtain for the foundation pit.

[0058] Next, step S3 is performed, where the waler 3 is formed by pouring concrete on top of the SMW method pile 100. Specifically, step S3 includes the following sub-steps:

[0059] S31: Tie the waler reinforcement at the top of the SMW method pile 100;

[0060] S32: According to the installation points of the front-supported diagonal brace assembly, pre-embed rigid connection pre-embedded parts simultaneously;

[0061] S33: After acceptance, pour concrete to complete the construction of waler 3.

[0062] Next, please refer to Figure 3 Execute step S4 to construct and install multiple front-supported inclined bracing components so that two front-supported inclined bracings 4 in each front-supported inclined bracing component are symmetrically arranged relative to the SMW method pile 100, and the near end of each front-supported inclined bracing is connected to the waler 3, and its far end is inserted obliquely into the foundation pit soil.

[0063] Specifically, executing S4 includes the following steps:

[0064] After the concrete of waler 3 reaches its design strength, install the front-supported diagonal bracing components according to the design intervals; the process of installing the paired front-supported diagonal bracing is as follows:

[0065] Weld the proximal ends of the two front-bracing diagonal braces to the opposite ends of the same rigid connection embedded part;

[0066] The far ends of the two root-supported diagonal braces are pushed obliquely into the soil of the foundation pit at the designed depth.

[0067] Understandably, the front-supported diagonal bracing components are installed in pairs according to the design angle and spacing. The specific values ​​of the spacing and angle should be adjusted and determined according to the design requirements of the project on site.

[0068] Next, step S5 is performed to seal the section of the front-supported diagonal brace 4 that is inserted into the soil and the joint between the front-supported diagonal brace and the soil.

[0069] Specifically, executing S5 includes the following sub-steps:

[0070] S51: Pre-grouting reinforcement is carried out on the section of the front-supported diagonal brace 4 inserted into the soil to form a soil reinforcement layer 5;

[0071] S52: High-pressure grouting is used to fill the gap between the front-supported diagonal brace 4 and the soil to form a grouting water-stopping layer 6. After the grouting water-stopping layer 6 is formed, the bottom slab cushion layer 7 is poured.

[0072] The entire construction process forms a water-stopping and sealing structure. The sections where the front-supported diagonal braces 4 are inserted into the soil and the gap nodes between the front-supported diagonal braces and the soil are treated. It does not require penetrating the water-stopping curtain, thus eliminating leakage channels and meeting the water-stopping requirements of foundation pits in high-water-level soft soil areas.

[0073] Next, proceed to step S6 for acceptance testing. Specifically, a special acceptance test is conducted on the stress deformation and water-stopping performance of the completed retaining wall of the foundation pit. After passing the acceptance test, the excavation of the foundation pit and subsequent construction work of the main structure are carried out.

[0074] It should be noted that, for the sake of simplicity, the foregoing method embodiments are all described as a series of actions. However, those skilled in the art should understand that this application is not limited to the described order of actions, as some steps may be performed in other orders or simultaneously according to this application. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions and modules involved are not necessarily essential to this application.

[0075] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0076] The present invention has the following advantages:

[0077] 1) Significantly improved construction efficiency: The layout of the front-supported inclined bracing components reduces the space occupied inside the foundation pit, eliminates the need for bracing replacement, and ensures almost no obstacles during earthwork excavation and main construction. The construction period is shortened by more than 30% compared to the traditional internal support system.

[0078] 2) Excellent retaining structure stability: Based on the waler, the front-supported inclined bracing components are connected with the SMW method piles to form an integrated and coordinated force-bearing system. The two front-supported inclined bracing components in each front-supported inclined bracing component are symmetrically distributed relative to the SMW method piles, which can effectively limit the lateral displacement of the pile body. The anti-overturning and anti-torsion performance is outstanding, and the deformation of the retaining structure is reduced by more than 40% compared with the traditional scheme.

[0079] 3) Reliable water-stopping performance: Water-stopping and sealing are carried out based on the water-stopping and sealing structure, without the need to penetrate the water-stopping curtain, eliminating leakage channels and meeting the water-stopping requirements of foundation pits in soft soil areas with high water levels.

[0080] 4) Excellent economic and environmental performance: Both the front-supported inclined bracing and the SMW method piles are recyclable, reducing the overall cost by more than 20% compared to traditional solutions. There is no construction waste, which meets the requirements of green construction.

[0081] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A partition wall for foundation pit retaining walls, characterized in that, include: One SMW method pile (100) is laid out along the design boundary line of the partition wall in the foundation pit; A purlin (3) is cast into the top of the SMW method pile (100); Multiple front-supported inclined bracing components, each front-supported inclined bracing component includes two front-supported inclined braces, the two front-supported inclined braces are symmetrically arranged relative to the SMW method pile (100), the near end of each front-supported inclined brace is connected to the waler (3), and its far end is inserted obliquely into the foundation pit soil. A water-stop sealing structure includes a soil reinforcement layer (5) and a grouting water-stop layer (6), which are respectively formed in the section where the front-supported inclined brace is inserted into the soil and the gap between the front-supported inclined brace and the soil.

2. The partition wall in the foundation pit retaining wall as described in claim 1, characterized in that, Also includes: The rigid connection embedded part is embedded in the waler (3) at the top of the SMW method pile (100) and extends out of the waler (3) at both ends.

3. The partition wall in the foundation pit retaining wall as described in claim 2, characterized in that, The proximal ends of the two front braces in each front brace assembly are connected to the opposite ends of the same rigid connection embedded part.

4. The partition wall in the foundation pit retaining structure as described in claim 1, characterized in that, The SMW method pile includes multiple triaxial cement-soil mixing piles (1) and multiple steel sections (2). The pile bodies of adjacent triaxial cement-soil mixing piles (1) are interlocked and overlapped. The multiple steel sections (2) are inserted longitudinally into the pile body of the corresponding triaxial cement-soil mixing pile (1) at predetermined intervals.

5. The partition wall in the foundation pit retaining structure as described in claim 4, characterized in that, The upper end of the steel section (2) extends beyond the top of the pile body of the three-axis cement-soil mixing pile (1) into which it is inserted, and is higher than the top surface of the waler (3).

6. The partition wall in the foundation pit retaining structure as described in any one of claims 1 to 5, characterized in that, The paired front bracings are arranged in a figure-eight shape. The horizontal angle between the two front bracings is 30°~60°, and the vertical angle between each front bracing (4) and the horizontal plane is 15°~45°.

7. A construction method for a partition wall in the foundation pit retaining structure as described in any one of claims 1 to 6, characterized in that, include: S1: Construction preparation; S2: SMW method piles (100) are constructed by laying out the partition wall in the foundation pit along the design boundary line. S3: A waler (3) is formed by pouring concrete on top of the SMW method pile (100). S4: Carry out the construction and installation of multiple front-supported inclined bracing components so that two front-supported inclined bracings (4) in each front-supported inclined bracing component are symmetrically arranged relative to the SMW method pile (100), and the near end of each front-supported inclined bracing is connected to the waler (3), and its far end is inserted obliquely into the foundation pit soil. S5: Waterproofing and sealing treatment shall be carried out on the section where the front-supported diagonal brace (4) is inserted into the soil and at the joint between the front-supported diagonal brace and the soil. S6: Conduct acceptance testing and construction.

8. The construction method of the partition wall in the foundation pit retaining wall as described in claim 7, characterized in that, When performing S3, the following steps are included: tying waler reinforcement bars to the top of the SMW method pile (100); According to the installation points of the front-supported diagonal brace assembly, the rigid connection embedded parts are pre-embedded simultaneously; After the acceptance inspection is passed, concrete will be poured to complete the construction of the waler (3).

9. The construction method of the partition wall in the foundation pit retaining wall as described in claim 7, characterized in that, When executing S4, the following steps are included: After the concrete of the waler (3) reaches the design strength, the front-supported diagonal bracing components are installed at the design intervals; the process of installing the paired front-supported diagonal bracing is as follows: Weld the proximal ends of the two front-bracing diagonal braces to the opposite ends of the same rigid connection embedded part; The far ends of the two root-supported diagonal braces are pushed obliquely into the soil of the foundation pit at the designed depth.

10. The construction method of the partition wall in the foundation pit retaining wall as described in claim 7, characterized in that, When executing S5, the following steps are included: Pre-grouting reinforcement is carried out on the section where the front-supported diagonal brace (4) is inserted into the soil to form a soil reinforcement layer (5). High-pressure grouting is used to fill the gap between the front-supported diagonal brace (4) and the soil to form a grouting water-stopping layer (6).

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