Friction type precast pile

Abstract

The utility model provides a kind of friction type prefabricated pile, it is related to the technical field of building engineering technology, the friction type prefabricated pile includes prefabricated pile main body, the prefabricated pile main body is provided with multiple equal diameter sections and multiple friction joints;And the equal diameter section and the friction joint are alternately arranged;The friction joint includes column section and special-shaped section, and the special-shaped section is set on the side of the column section away from the first end;The special-shaped section has multiple inner concave surfaces recessed in the outer surface of the column section.The prefabricated pile main body of the friction type prefabricated pile provided by the utility model has multiple friction joints, and multiple inner concave surfaces are arranged on the friction joint;When prefabricated pile is oriented to construction, soil body can move along inner concave surface, and the engagement with soil body is better and more compact, and the recovery speed of later soil body is also greatly improved.

Description

Technical Field

[0001] This utility model relates to the technical field of building engineering technology, and in particular to a friction type precast pile. Background Technology

[0002] The high compressibility of deep soft soil layers imposes dual constraints on traditional foundation treatment methods, including limitations on construction period and depth. Conventional methods such as surcharge preloading require the addition of pile foundations to form a composite foundation, resulting in redundant procedures and increased costs. Precast pile technology, due to its advantages of factory production, controllable quality, high construction efficiency, and reliable bearing capacity, has gradually become the mainstream choice for soft soil treatment. However, while existing precast pile technology integrates foundation treatment and pile foundation functions through soil squeezing, its uniform cross-section design leads to uneven distribution of skin friction at the pile-soil interface, which can easily cause bearing capacity reduction, especially in ultra-soft soils. More importantly, remedial measures such as post-grouting to improve bearing capacity not only increase construction steps but also introduce new quality risks due to poor process controllability, reflecting the inherent defect of insufficient adaptability of traditional pile types to the deformation characteristics of soft soil.

[0003] Current pile optimization focuses primarily on lateral cross-sectional variations (such as the protruding ribs of bamboo-joint piles and double-casing grouting), but fixed parameter designs struggle to match the mechanical gradients of the soil layers, and sudden changes in radial stiffness easily lead to stress concentration. Innovations in construction techniques are limited by reliance on specialized equipment (such as static drilling and root-planting methods) or difficulties in controlling grout uniformity, hindering industrial-scale adoption. The deeper contradiction lies in the fact that existing variable cross-section structures have failed to establish a dynamic coordination mechanism between longitudinal stiffness and soil strength. While existing publicly available technical solutions attempt to adjust radial stiffness, they sacrifice the overall integrity of the pile. This exposes three technical gaps: 1. Discontinuous stiffness chain in the pile-soil system; 2. Disconnect between structural innovation and construction feasibility; 3. Lack of an active control system for interfacial friction. Utility Model Content

[0004] The purpose of this invention is to provide a friction-type precast pile to solve the problem of uneven distribution of frictional resistance at the pile-soil interface in current precast piles, which is prone to causing bearing capacity failure, especially in ultra-soft soil. The remedial measures such as post-grouting adopted to improve bearing capacity not only increase the construction process, but also have poor process controllability and may introduce new quality risks.

[0005] This utility model provides a friction type precast pile, including a precast pile body, the precast pile body having a first end and a second end, and multiple equal-diameter sections and multiple friction joints are provided on the precast pile body; and the equal-diameter sections and the friction joints are alternately arranged; The friction joint includes a cylindrical section and an irregular section, and the irregular section is disposed on the side of the cylindrical section away from the first end; The irregular segment has multiple concave surfaces that are recessed into the outer surface of the cylindrical segment.

[0006] In an optional embodiment, the direction from the first end to the second end is the implantation direction of the precast pile body, and the precast pile body includes an upper section, a middle section and a lower end that are connected in sequence. In an optional embodiment, the upper section includes at least one equal-diameter section and at least one friction joint, the first end is located on the equal-diameter section, and the distance between the first end and the adjacent friction joint is not less than 1000mm.

[0007] In an optional embodiment, the lower section includes at least one equal-diameter section and at least one friction joint, the second end is located on the equal-diameter section, and the distance between the second end and the adjacent friction joint is no more than 300 mm.

[0008] In an optional embodiment, the middle section includes at least one equal-diameter section and at least one friction joint; and the sum of the lengths of an adjacent equal-diameter section and the friction joint of the middle section is not greater than 2000 mm.

[0009] In an optional embodiment, the concave surface is provided on the irregular section, and the arc length of the concave surface is not less than 98% of the length S after its axial projection intersects with the projection of the outer arc surface of the cylindrical section. In an optional embodiment, a stress-dissipating end is provided at the end of the concave surface away from the second end, the stress-dissipating end being used to connect the concave surface with the outer arc surface of the cylindrical segment.

[0010] In an optional embodiment, the stress dissipation end is located on the cylindrical segment or the stress dissipation end is located on the irregular segment.

[0011] In an optional embodiment, the length of the columnar segment is not less than 150 mm. In an optional embodiment, the difference between the outer diameter of the cylindrical segment and the outer diameter of the equal-diameter segment is 20mm-80mm.

[0012] In an optional embodiment, the precast pile body is provided with a direction mark, the direction mark having a depth greater than or equal to 2mm.

[0013] The precast pile body of the friction type provided by this utility model has multiple friction joints, and multiple concave surfaces are provided on the friction joints; when the precast pile is constructed according to the orientation, the soil can move along the concave surface, which makes the interlocking with the soil better and tighter, and also greatly improves the recovery speed of the soil in the later stage. Attached Figure Description To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0014] Figure 1 A schematic diagram of the structure of a friction-type precast pile provided in an embodiment of this utility model; Figure 2 for Figure 1 The diagram shows the structural schematic of the AA section of the friction-type precast pile. Figure 3 for Figure 1 A partial enlarged view of B of the friction-type precast pile shown; Figure 4 for Figure 1 A schematic diagram of the structure of a friction-type precast pile from another angle is shown. Figure 5 for Figure 1 The diagram shows a structural schematic of a friction-type precast pile at another angle. Figure 6 for Figure 5 A partial enlarged view of C in the friction-type precast pile shown; Figure 7 for Figure 1 The diagram shows another structural schematic of a friction-type precast pile; Figure 8 for Figure 7 The diagram shows a partial enlarged view of point D of the friction-type precast pile.

[0015] Icons: 100 - Equal diameter section; 200 - Friction joint; 201 - Columnar section; 202 - Irregular section; 2021 - Concave surface; 2022 - Stress dissipation end; 2023 - Outer arc surface; 300 - First end; 400 - Second end; 500 - Transition section; 600 - Direction indicator. Detailed Implementation

[0016] The terms “first,” “second,” “third,” etc., are used only for distinguishing descriptions and do not indicate a sequence number, nor should they be interpreted as indicating or implying relative importance.

[0017] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0018] In the description of this application, it should be noted that the terms "inner", "outer", "left", "right", "upper", "lower", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They are only for the convenience of describing this application 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 this application.

[0019] In the description of this application, unless otherwise expressly specified and limited, the terms “set up,” “install,” “connect,” and “link” shall be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection; as a mechanical connection or an electrical connection; as a direct connection or an indirect connection through an intermediate medium; or as a connection within two components.

[0020] The technical solution of this application will now be clearly and completely described with reference to the accompanying drawings.

[0021] Example Reference Figures 1-8 This utility model provides a friction type precast pile, wherein the precast pile body has a first end 300 and a second end 400, and the precast pile body is provided with a plurality of equal diameter sections 100 and a plurality of friction joints 200; and the equal diameter sections 100 and the friction joints 200 are alternately arranged. The friction joint 200 includes a cylindrical section 201 and an irregular section 202, and the irregular section 202 is disposed on the side of the cylindrical section 201 away from the first end 300; The irregular segment 202 has multiple concave surfaces 2021 recessed into the outer surface of the cylindrical segment.

[0022] In some embodiments, the precast pile body is composed of concrete, main reinforcement and spiral reinforcement. An upper pile sleeve and a lower pile sleeve are respectively provided at both ends of the precast pile body along its length. The upper pile sleeve and the lower pile sleeve are made of metal and are existing products.

[0023] Multiple equal-diameter sections 100 and multiple friction joints 200 of the precast pile body are alternately arranged and connected; multiple concave surfaces 2021 are provided at one end of the friction joint 200, preferably, the multiple concave surfaces 2021 are evenly arranged on the friction joint 200.

[0024] The concave surface 2021 of the friction joint 200 of the precast pile body allows the soil to move along the inner arc surface 2021 when the precast pile is constructed in the correct orientation, resulting in better and tighter engagement with the soil and significantly improving the recovery speed of the soil in the later stage.

[0025] Adjacent friction joints 200 are distributed at unequal intervals. The spacing between adjacent friction joints 200 in soil layers with better soil conditions (referring to soft soil, silt, and other soil layers that are easy to drive piles) is greater than that in soil layers with poorer soil conditions. This fully utilizes the function of the friction joints 200, enhances the interlocking with the soil, and thus ensures the vertical bearing capacity of the precast pile body.

[0026] In an optional embodiment, the direction from the first end 300 to the second end 400 is the implantation direction of the precast pile body, and the precast pile body includes an upper section, a middle section and a lower end that are connected in sequence. Reference Figure 5 In an optional embodiment, the upper section (L1) includes at least one equal diameter section 100 and at least one friction joint 200, the first end 300 is located on the equal diameter section 100, and the distance between the first end 300 and the adjacent friction joint 200 is not less than 1000mm.

[0027] In some embodiments, the upper section of the precast pile body includes one or more equal-diameter sections 100 and one or more friction joints 200; one end of the equal-diameter section 100 is connected to the friction joint 200; the distance between the first end 300 and the nearest friction joint 200 is not less than 1000mm, thus ensuring that after the equal-diameter section 100 of the upper section is spliced, sufficient operating space is reserved for the construction clamp, preventing the construction clamp from being clamped on the irregular section of the friction joint 200 and causing damage to the pile body.

[0028] In an optional embodiment, the lower section (L3) includes at least one equal diameter section 100 and at least one friction joint 200, the second end 400 is located on the equal diameter section 100, and the distance between the second end 400 and the adjacent friction joint 200 is no more than 300 mm.

[0029] In some embodiments, the equal-diameter section 100 of the lower segment is connected to the friction joint 200; the lower segment includes one or more equal-diameter sections 100 and one or more friction joints 200; the distance between the second end 400 and the nearest friction joint 200 is no greater than 300 mm; this ensures that all friction joints 200 in the lower segment enter the bearing layer, so that the pile end bearing capacity is calculated based on the outer diameter of the friction joint 200. If the calculation is based on the outer diameter of the equal-diameter section 100, the pile end bearing capacity will be reduced by at least 15%.

[0030] In an optional embodiment, the middle section (L2) includes at least one equal diameter section 100 and at least one friction joint 200; and the sum of the lengths of an adjacent equal diameter section 100 and friction joint 200 of the middle section is not greater than 2000 mm.

[0031] In some embodiments, one end of the middle section is the upper section and the other end is the lower section; the middle section includes at least one equal diameter section 100 and at least one friction joint 200, and the equal diameter section 100 and the friction joint 200 are alternately arranged, and the sum of the lengths of an adjacent equal diameter section 100 and a friction joint 200 in the middle section is generally no more than 2000 mm.

[0032] Since the maximum stroke of the static pressure pile construction equipment is 2m, the length of the middle section can be adjusted accordingly when the maximum stroke of the corresponding static pressure pile construction equipment is adjusted.

[0033] Reference Figure 2 and Figure 3 In an optional embodiment, the friction joint 200 includes a columnar section 201 and an irregular section 202, and the irregular section 202 is disposed on the side of the columnar section 201 away from the upper pile sleeve. The concave surface 2021 is provided on the irregular section 202, and the arc length of the concave surface 2021 is not less than 98% of the length S after its axial projection intersects with the projection of the outer arc surface 2023 of the cylindrical section 201. In some embodiments, the irregular segment 202 is provided with multiple concave surfaces 2021, which are generally arc surfaces. To ensure that the total contact area between the inner arc surface of the concave surface 2021 and the outer arc surface 2023 of the cylindrical segment 201 and the outer soil is almost equal to the contact area between the circumscribed circle and the soil, concrete usage can be reduced by more than 15% while reducing the contact area with the soil by a maximum of 2% (in most cases, there is no reduction). At the same time, this structure is beneficial to the precast pile during construction, and it is also more conducive to the soil being squeezed in along the concave surface 2021 when subjected to compression, so as to achieve rapid soil recovery after the precast pile is constructed.

[0034] The outer diameter of the friction joint 200 is larger than the outer diameter of the equal diameter section 100, and the end of the friction joint 200 away from the first end 300 has a plurality of concave surfaces 2021, which extend to the end of the friction joint 200 along the implantation direction; and the plurality of concave surfaces 2021 are arranged in the irregular section 202, and the plurality of concave surfaces 2021 are evenly spaced along the axial direction of the precast pile body.

[0035] The concave surface 2021 can also be trapezoidal or other shapes. The length of the concave surface 2021 is greater than or equal to the arc length of the outer circular surface 2023, thus ensuring the contact area between the precast pile and the soil, thereby ensuring the vertical bearing capacity of the pile.

[0036] The projection of the inner arc surface of all concave surfaces 2021 of the irregular section is tangent to the projection of the circle containing the equal-diameter section 100, which ensures the maximum contact area with the outer soil.

[0037] In an optional embodiment, a transition section 500 is provided between the cylindrical section 201 of the friction joint 200 and the equal diameter section 100. The outer diameter of one end of the transition section 500 is the same as the outer diameter of the cylindrical section 201 of the friction joint 200, and the outer diameter of the other end of the transition section 500 is the same as the outer diameter of the equal diameter section 100. Reference Figure 5 , Figure 6 , Figure 7 and Figure 8 In an optional embodiment, a stress-dissipating end 2022 is provided at the end of the concave surface 2021 away from the second end 400. The stress-dissipating end 2022 is used to connect the concave surface 2021 with the outer arc surface 2023 of the cylindrical segment 201. Multiple stress-dissipating ends 2022 connect the concave surface 2021 and the outer arc surface 2023 together. The lengths of the multiple stress-dissipating ends 2022 may be the same or different. The main function of the stress-dissipating ends 2022 is to prevent the cross-sectional stress at this location from being too concentrated, which could lead to circumferential cracking of the precast pile during lifting.

[0038] The stress dissipation end 2022 is located on the columnar section 201 or the stress dissipation end 2022 is located on the irregular section 202.

[0039] Reference Figure 7 In an optional embodiment, the precast pile body is provided with a direction indicator 600.

[0040] In some embodiments, the friction joint 200 includes a columnar section 201 and an irregular section 202. A direction indicator 600 is provided on the precast pile body. The direction indicator 600 facilitates the correct insertion of the precast pile body by construction personnel. The irregular section 202 is located below the columnar section 201. During the insertion process, the irregular section 202 is preferentially inserted into the foundation. The direction indicator 600 is provided on the columnar section 201 of the friction joint 200, which is close to the second end 400 of the precast pile body.

[0041] In an optional embodiment, the length of the columnar segment 201 is not less than 150 mm. In some embodiments, the length of the column section 201 needs to be no less than 150mm, so that when the precast piles are stacked, the contact area of ​​adjacent precast piles is larger, making them easier to stack and transport. This can prevent the precast piles from rolling, avoid damage to irregular sections, and prevent the column section 201 from being crushed due to excessive pressure.

[0042] In an optional embodiment, the difference between the outer diameter of the cylindrical segment 201 and the outer diameter of the equal-diameter segment 100 is 20mm-80mm.

[0043] In some embodiments, the difference between the outer diameter of the column section 201 and the outer diameter of the equal-diameter section 100 is within a certain range. This range of difference is conducive to the exertion of the side friction resistance between the pile and the soil, thereby increasing the side friction resistance of the pile.

[0044] The precast pile body includes an upper section, a middle section and a lower section connected in sequence; wherein, the equal diameter section 100 can be a hollow ring or a polygonal shape. The pile body is divided into three regions: upper section (L1), middle section (L2), and lower section (L3). The transverse cross-section of the equal diameter section 100 is in the shape of a hollow ring or polygon. The cross-sectional shape of the equal diameter section 100 is compatible with construction clamps on the market.

[0045] A directional marker 600 is installed on the precast pile body. This marker is typically placed in a prominent position, usually on the friction joint 200 adjacent to the lower pile sleeve. The directional marker is engraved on the outer arc surface 2023 of the friction joint 200, with a depth of not less than 2mm. This prevents wear during transportation and construction from obscuring the directional marker, which would hinder operator work. It also prevents paint wear during transportation and construction when marking is required. The length of the lower end is generally between 1m and 1.5m, and the sum of the lengths of adjacent friction joints and equal-diameter sections in the middle section does not exceed 2m. This ensures the lower section fully penetrates the bearing stratum, allowing the pile tip bearing capacity to be calculated based on the diameter of the outer arc surface 2023, increasing the bearing capacity by more than 15% compared to calculations based on the inner arc surface diameter, further reducing the unit bearing capacity cost of the pile foundation.

[0046] The precast pile body of the friction type precast pile provided by this utility model has multiple friction joints 200, and multiple concave surfaces 2021 are provided on the friction joints 200. When the friction type precast pile is constructed according to the orientation, the soil can move along the concave surface 2021, which makes the soil better and tighter, and also greatly improves the recovery speed of the soil in the later stage.

[0047] Friction-type precast piles can reduce construction difficulty while effectively ensuring the interlocking force between the pile body and the soil. The pile tip can be smoothly constructed to the design elevation, further reducing the damage to the pile body caused by the increased number of hammer blows or increased pile driving force due to the inability to enter the bearing layer, thereby avoiding potential quality hazards to the project.

[0048] Friction-type precast piles can adjust the spacing of the friction joints 200 according to different soil types, while ensuring bearing capacity, to better match the soil conditions.

[0049] Friction-type precast piles are equipped with at least one direction indicator to clarify the orientation of the precast pile, further improving the convenience of construction and reducing the impact of human factors.

[0050] This utility model also provides a method for using friction type precast piles, including: Step 1, constructing the second end 400 of the friction type precast pile downwards according to the direction indicated by the direction mark 600 on the friction type precast pile; Step 2: When the first end 300 of the friction type precast pile is 0.5-1m above the ground, connect the next friction type precast pile to the first end 300 of the previous friction type precast pile and continue construction.

[0051] In an optional implementation, the method further includes: step 3, repeating step 2 once or multiple times until the second end 400 of the lowest friction-type precast pile enters the designed soil layer.

[0052] When constructing a single-section friction-type precast pile, simply install the pile with the directional indicator pointing downwards. For multi-section friction-type precast piles, first install the piles downwards according to the 60° directional indicator, with the upper section temporarily 0.5-1m above ground level. Connect the next friction-type precast pile to the end of the upper section and continue construction until the lower section reaches the designed soil layer, completing the process. When adjacent friction-type precast piles require welding connections, end plates are installed at both ends of the friction-type precast piles. When using other methods, such as pin-type mechanical connections, end plates are not required at the ends of the friction-type precast piles.

[0053] The method of using friction precast piles provided by this utility model involves installing the direction mark 600 of the friction precast pile to indicate the direction, and then constructing the second end 400 of the friction precast pile with the direction facing downwards. This ensures that the friction precast pile is installed correctly and reduces the requirements for construction personnel.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A friction-type precast pile, characterized in that, The precast pile body includes a first end (300) and a second end (400), and the precast pile body is provided with a plurality of equal diameter sections (100) and a plurality of friction joints (200); and the equal diameter sections (100) and the friction joints (200) are arranged alternately. The friction joint (200) includes a cylindrical section (201) and a non-circular section (202), and the non-circular section (202) is disposed on the side of the cylindrical section (201) away from the first end (300); The irregular segment (202) has multiple concave surfaces (2021) that are recessed into the outer surface of the cylindrical segment (201).

2. The friction-type precast pile according to claim 1, characterized in that, The direction from the first end (300) to the second end (400) is the implantation direction of the precast pile body, and the precast pile body includes an upper section, a middle section and a lower end that are connected in sequence.

3. The friction-type precast pile according to claim 2, characterized in that, The upper section includes at least one equal diameter section (100) and at least one friction joint (200), the first end (300) is located on the equal diameter section (100), and the distance between the first end (300) and the adjacent friction joint (200) is not less than 1000mm.

4. The friction-type precast pile according to claim 3, characterized in that, The lower section includes at least one equal diameter section (100) and at least one friction joint (200), the second end (400) is located on the equal diameter section (100), and the distance between the second end (400) and the adjacent friction joint (200) is no more than 300 mm.

5. The friction-type precast pile according to claim 4, characterized in that, The middle section includes at least one equal diameter section (100) and at least one friction joint (200); and the sum of the lengths of adjacent equal diameter sections (100) and friction joints (200) of the middle section is not greater than 2000 mm.

6. The friction-type precast pile according to claim 1, characterized in that, The concave surface (2021) is provided on the irregular section (202), and the arc length of the concave surface (2021) is not less than 98% of the length S after its axial projection intersects with the projection of the outer arc surface (2023) of the cylindrical section (201).

7. The friction-type precast pile according to claim 6, characterized in that, A stress-dissipating end (2022) is provided at the end of the concave surface (2021) away from the second end (400), and the stress-dissipating end (2022) is used to connect the concave surface (2021) with the outer arc surface (2023) of the cylindrical segment (201).

8. The friction-type precast pile according to claim 7, characterized in that, The stress dissipation end (2022) is located on the columnar segment (201) or the stress dissipation end (2022) is located on the irregular segment (202).

9. The friction-type precast pile according to claim 1, characterized in that, The length of the column segment (201) is not less than 150mm.

10. The friction-type precast pile according to claim 1, characterized in that, The difference between the outer diameter of the cylindrical section (201) and the outer diameter of the equal-diameter section (100) is 20mm-80mm.

11. The friction-type precast pile according to claim 1, characterized in that, The precast pile body is provided with a direction mark (600), and the depth of the direction mark is greater than or equal to 2mm.

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