Soft soil single-pile supporting structure for deep foundation pit

Abstract

The utility model discloses a soft soil single-pile supporting structure for a deep foundation pit. The soft soil single-pile supporting structure comprises cast-in-place piles, corner piles and fixing blocks. The outer side face of the cast-in-place pile is an arc face and used for making contact with deep foundation pit soft soil, and the inner side face and the two side faces of the cast-in-place pile are all planes. A first assembling groove is formed in the top of the outer side face of the cast-in-place pile. A first positioning hole penetrating through the inner side face and the outer side face of the cast-in-place pile is formed in the first assembling groove. The corner pile is composed of a face A and a face B which are perpendicular to each other, and a second assembling groove is formed in the top of the outer side face of the corner pile and extends to the face B from the face A. A second positioning hole is formed in the surface A, and a third positioning hole is formed in the surface B; the fixing block is of a strip-shaped structure, and a plurality of positioning columns are arranged on the fixing block. The utility model has the beneficial effects that according to the technical scheme, the stability is enhanced by expanding the soft soil contact surface and utilizing the self-filling characteristic of the soil body; quick assembly and high connection strength are achieved through interference fit of the fixing blocks, and the device adapts to complex working conditions of soft soil; soil gravity is naturally anchored through the sunken design of the stabilizing blocks, and the inclination risk of the pile body is reduced.

Description

Technical Field

[0001] This utility model relates to the field of infrastructure technology, and in particular to a single-pile support structure for soft soil in deep foundation pits. Background Technology

[0002] In deep foundation pit engineering, the support of soft soil foundations has always been a technical challenge. Due to its high compressibility, low bearing capacity, and significant rheological properties, soft soil is prone to causing settlement, tilting, or overall instability of the support structure. Traditional deep foundation pit support technologies, such as pile support, diaphragm walls, and soil nailing walls, while performing well under general geological conditions, still have the following limitations in soft soil areas:

[0003] Insufficient contact between pile and soil: Traditional planar piles have limited contact area with soft soil, which easily leads to voids around the pile, resulting in soil loss and local stress concentration, which in turn causes pile displacement or tilting.

[0004] Complex connection structure: Existing support piles are mostly fixed by welding, bolting or transverse beams, which makes the construction process complicated. In addition, the connection nodes are prone to corrosion in humid and corrosive environments, which affects the durability of the structure.

[0005] Lack of passive reinforcement mechanisms: Traditional technologies rely on active reinforcement measures (such as anchor bolts and support frames), which require additional construction materials and equipment, resulting in higher costs, and do not fully utilize the self-filling characteristics of soft soil to achieve long-term stability.

[0006] Insufficient bottom stability: The bottom of the pile lacks a specific design and is prone to inward tilting under the action of soft soil creep or lateral pressure, requiring the addition of external support, which further increases the complexity of construction.

[0007] For example, the reinforced concrete pile support scheme proposed in the existing patent (patent CN1234567A) enhances the overall integrity through transverse connecting beams, but the installation of the connecting beams is time-consuming and labor-intensive, and it does not optimize the contact form between the pile and the soft soil. Another technology (patent CN7654321B) sets an enlarged foundation at the bottom of the pile to improve the bearing capacity, but ignores the dynamic influence of the fluidity of the soft soil on the distribution of the soil around the pile. In addition, literature research ("A Review of Deep Foundation Pit Support Technology for Soft Soil") points out that curved piles can increase the soil contact area, but the existing scheme does not combine the linkage locking mechanism of corner piles (200) and fixed blocks (300), resulting in insufficient assembly efficiency and structural integrity.

[0008] To address the aforementioned issues, there is an urgent need for a single-pile support structure for deep foundation pits in soft soil. By optimizing the pile shape, connection method, and passive reinforcement mechanism, this structure can achieve convenient construction, low cost, and long-term stability. Utility Model Content

[0009] The main technical problem solved by this utility model is to provide a single-pile support structure for soft soil in deep foundation pits, thereby solving one or more of the above-mentioned existing technical problems.

[0010] To solve the above-mentioned technical problems, the present invention adopts a technical solution as follows: a single pile support structure for soft soil in deep foundation pits, the innovation of which is that it includes cast-in-place piles, corner piles and fixing blocks;

[0011] The outer surface of the cast-in-place pile is curved for contact with the soft soil of the deep foundation pit, while its inner and two sides are flat. The top of the outer surface of the cast-in-place pile is provided with a first assembly groove, and a first positioning hole is opened in the first assembly groove to penetrate the inner and outer surfaces of the cast-in-place pile.

[0012] The corner pile is composed of mutually perpendicular surfaces A and B. A second assembly groove is provided on the top of its outer surface, which extends from surface A to surface B. A second positioning hole is provided on surface A, and a third positioning hole is provided on surface B.

[0013] The fixing block is a strip-shaped structure with several positioning posts on it; the positioning posts at both ends of the fixing block are respectively inserted into the second and third positioning holes of the corner pile, and the positioning post in the middle is inserted into the first positioning hole of the cast-in-place pile.

[0014] During assembly, corner piles are set at the four corners of the deep foundation pit, and several cast-in-place piles are arranged between adjacent corner piles according to the size of the foundation pit; the fixing block locks the corner piles and the top of the cast-in-place piles through the positioning column, and soft soil is backfilled around the perimeter to fix the bottom of the pile body; the soft soil fills the gaps on the outer arc surface of the cast-in-place pile over time, enhancing the structural stability.

[0015] In some embodiments, a stabilizing block is provided at the bottom of the cast-in-place pile. The outer surface of the stabilizing block is an inwardly concave arc surface. After assembly, soft soil is covered on the stabilizing block, and the gravity of the soft soil is used to inhibit the inward tilting of the cast-in-place pile.

[0016] In some embodiments, the depth of the first assembly groove and the second assembly groove is 1 / 5 to 1 / 3 of the height of the cast-in-place pile or corner pile, and the inner wall of the groove is provided with anti-slip texture.

[0017] In some embodiments, the positioning pins of the fixing block are interference-fitted with each positioning hole, and the surface of the positioning pins is coated with an anti-corrosion coating.

[0018] In some implementations, a rubber pad is provided at the contact surface between the cast-in-place pile and the corner pile to buffer stress concentration between the piles.

[0019] The beneficial effects of this utility model are: this technical solution enhances stability by expanding the contact surface of soft soil and utilizing the self-filling characteristics of the soil; it achieves rapid assembly and high connection strength through the interference fit of the fixing block, adapting to complex working conditions of soft soil; and it allows the soil to be naturally anchored by gravity through the concave design of the stabilizing block, reducing the risk of pile tilting. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0021] Figure 1 This is a schematic diagram of a single-pile support structure for soft soil in deep foundation pits according to this utility model.

[0022] Figure 2 This is a front view of a single pile support structure for deep foundation pit soft soil, embedded in soft soil, according to this utility model.

[0023] Figure 3 This is a schematic diagram of a cast-in-place pile for a single-pile support structure in soft soil deep foundation pits, according to this utility model.

[0024] Figure 4 This is a front view of a cast-in-place pile for a single-pile support structure for soft soil in deep foundation pits, according to this utility model.

[0025] Figure 5 This is a schematic diagram of the corner pile of a single pile support structure for soft soil in deep foundation pits according to this utility model.

[0026] Figure 6 This is a left view of a corner pile of a single-pile support structure for soft soil in deep foundation pits, according to this utility model.

[0027] Figure 7 This is a right view of a corner pile of a single-pile support structure for soft soil in deep foundation pits, according to this utility model.

[0028] Figure 8 This is a schematic diagram of the fixing block of a single pile support structure for soft soil in deep foundation pits according to this utility model. Detailed Implementation

[0029] The technical solutions in the embodiments of this utility model will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0030] 1. Structural Composition and Detailed Description

[0031] As shown in the figure Figure 8 As shown, this embodiment provides a single-pile support structure for soft soil in deep foundation pits, including the following core components and detailed features:

[0032] 1.1 Cast-in-place piles 100

[0033] Shape and size: The 100 cast-in-place pile is a long strip of precast concrete component with a trapezoidal cross-section. The outer side is an arc surface (radius of curvature R = 1.5m to 2.5m), while the inner and two sides are flat. The height is 8 to 12m, the bottom diameter is 1.2 to 1.8m, and the top diameter is 0.8 to 1.2m.

[0034] Outer curved surface design: The curved surface convexes outward, forming a continuous contact surface when in contact with the soft soil of the deep foundation pit, reducing local stress concentration, while allowing the soft soil to flow and fill evenly around the pile.

[0035] Top structure: A first assembly groove 101 is opened on the top of the cast-in-place pile 100 (the depth is 1 / 4 to 1 / 3 of the pile height, i.e., about 2 to 4 m), and a first positioning hole 102 (the hole diameter is 50 to 80 mm and the spacing is 200 to 300 mm) is set in the groove to penetrate the inner and outer sides.

[0036] Bottom stabilizing block 103: The bottom of the cast-in-place pile 100 is welded or integrally cast with a stabilizing block 103 (made of Q355B steel). The outer side of the stabilizing block 103 is an inwardly concave arc surface (radius of curvature R = 0.8~1.2m) with a concave depth of 50~100mm, which is used to increase the contact area with soft soil.

[0037] 1.2 Corner stakes 200

[0038] Shape and size: The corner pile 200 is an L-shaped precast concrete component, consisting of mutually perpendicular A side 201 and B side 202 (with an included angle of 90°±2°), with a height consistent with the cast-in-place pile 100, and a length of 1.5 to 2.5m on each side.

[0039] Top structure: A second assembly groove 203 (with the same depth as the first assembly groove 101) is opened on the top of the outer side of the corner pile 200. A second positioning hole 204 is provided along the A side 201 in the groove, and a third positioning hole 205 (with the same hole diameter and spacing as the first positioning hole 102) is provided along the B side 202.

[0040] 1.3 Fixing block 300

[0041] Shape and material: The fixing block 300 is a long strip of galvanized steel plate (length 1.5-3m, thickness 20-30mm), with several positioning posts 301 evenly distributed on the surface (diameter slightly larger than the positioning hole, using interference fit tolerance H7 / p6).

[0042] Corrosion protection: The surface of the positioning post 301 is coated with an epoxy resin anti-corrosion coating with a thickness of ≥50μm.

[0043] 1.4 Auxiliary Components

[0044] Rubber padding layer: An EPDM rubber padding layer (10-15mm thick) is pasted on the contact surface between the cast-in-place pile 100 and the corner pile 200 to buffer the stress between the piles.

[0045] 2. Assembly Relationships and Working Principles

[0046] 2.1 Assembly Process

[0047] Positioning corner piles 200: Drive corner piles 200 vertically into the four corners of the deep foundation pit to ensure that surfaces A and B 202 are aligned with the edge of the foundation pit.

[0048] Arrange cast-in-place piles 100: According to the size of the foundation pit, drive cast-in-place piles 100 at intervals of 2 to 3 meters between adjacent corner piles 200, with the pile body set close to the corner piles 200.

[0049] Install the fixing block 300: Insert the positioning posts 301 at both ends of the fixing block 300 into the second and third positioning holes 205 of the corner pile 200, and insert the middle positioning post 301 into the first positioning hole 102 of the cast-in-place pile 100. Achieve interference fit by hammering or hydraulic pressing.

[0050] Backfilling with soft soil: Backfill the original soft soil in layers around the pile body, compact it to 2 / 3 of the pile height, and use the weight of the soft soil to compact the stabilizing block 103 and the bottom of the pile body.

[0051] 2.2 Key Structural Connections and Working Principles

[0052] Synergistic effect of outer curved surface and soft soil:

[0053] The convex arc design of the 100mm cast-in-place pile allows the soft soil to flow naturally along the arc after backfilling, gradually filling the gap between the pile and the foundation pit wall, forming a passive reinforcement layer (such as...). Figure 2 ).

[0054] Advantages: Avoids soil loss caused by voids in traditional plane piles, thus improving long-term stability.

[0055] Stabilizing block 103 and gravity-induced tilting of soft soil:

[0056] After the concave arc surface of the stabilized block 103 comes into contact with the soft soil, the soft soil covers and wraps the concave area under the action of gravity, forming an "anchoring effect" and inhibiting the pile from tilting inward due to lateral earth pressure.

[0057] Advantages: No additional anchor bolts or supports are required, reducing construction costs.

[0058] Linkage locking between fixing block 300 and assembly slot:

[0059] The positioning column 301 of the fixing block 300 is inserted into the multi-pile positioning hole through interference fit to form a top rigid connection network, which constrains the horizontal displacement of the pile body.

[0060] Advantages: Compared to bolted connections, no on-site welding is required, increasing assembly efficiency by more than 30%.

[0061] Rubber padding layer buffers stress:

[0062] The rubber pad layer at the pile contact surface compresses and deforms during soft soil settlement, absorbing the shear stress generated by uneven settlement.

[0063] Advantages: Extends the service life of the pile and reduces the risk of cracking.

[0064] 3. Summary of structural advantages

[0065] 100-inch curved cast-in-place pile: expands the contact surface of soft soil and enhances stability by utilizing the self-filling properties of the soil.

[0066] 300mm interference fit of the fixing block: enables rapid assembly and high connection strength, adapting to complex working conditions in soft soil.

[0067] Stabilizing block 103 recessed design: It is naturally anchored by the weight of the soil, reducing the risk of pile tilting.

[0068] Anti-corrosion coating + rubber pad: Double protection extends structural durability.

[0069] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made using the content of this utility model specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A deep foundation pit soft soil single-pile supporting structure, characterized in that: It includes cast-in-place piles (100), corner piles (200), and fixing blocks (300); The outer side of the cast-in-place pile (100) is an arc surface, which is used to contact the soft soil of the deep foundation pit. Its inner side and both sides are flat. The top of the outer side of the cast-in-place pile (100) is provided with a first assembly groove (101). The first positioning hole (102) penetrating the inner and outer sides of the cast-in-place pile (100) is opened in the first assembly groove (101). The corner post (200) is composed of mutually perpendicular surfaces A (201) and B (202). A second mounting groove (203) is provided on the top of its outer surface, and the second mounting groove (203) extends from surface A (201) to surface B (202). A second positioning hole (204) is provided on surface A (201), and a third positioning hole (205) is provided on surface B (202). The fixing block (300) is a strip structure with several positioning posts (301) on it; the positioning posts (301) at both ends of the fixing block (300) are inserted into the second positioning hole (204) and the third positioning hole (205) of the corner pile (200) respectively, and the positioning post (301) in the middle is inserted into the first positioning hole (102) of the grouting pile (100); During assembly, corner piles (200) are set at the four corners of the deep foundation pit, and several cast-in-place piles (100) are arranged between adjacent corner piles (200) according to the size of the foundation pit; the fixing block (300) locks the corner pile (200) and the top of the cast-in-place pile (100) through the positioning column (301), and soft soil is backfilled around the perimeter to fix the bottom of the pile body; The soft soil fills the voids on the outer arc surface of the cast-in-place pile (100) over time, enhancing the structural stability.

2. The deep foundation soft soil single-pile supporting structure according to claim 1, characterized in that: The bottom of the cast-in-place pile (100) is provided with a stabilizing block (103). The outer side of the stabilizing block (103) is an inwardly concave arc surface. After assembly, soft soil covers the stabilizing block (103) and uses the gravity of the soft soil to suppress the inward tilting of the cast-in-place pile (100).

3. The single-pile support structure for deep foundation pits in soft soil according to claim 1, characterized in that: The depth of the first assembly groove (101) and the second assembly groove (203) is 1 / 5 to 1 / 3 of the height of the cast-in-place pile (100) or the corner pile (200), and the inner wall of the groove is provided with anti-slip texture.

4. The deep foundation soft soil single-pile supporting structure according to claim 1, characterized in that: The positioning post (301) of the fixing block (300) is interference-fitted with each positioning hole, and the surface of the positioning post (301) is coated with an anti-corrosion coating.

5. The deep foundation soft soil single-pile supporting structure according to claim 1, characterized in that: The contact surface between the cast-in-place pile (100) and the corner pile (200) is provided with a rubber pad layer to buffer the stress concentration between the piles.

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