Prefabricated concrete polygonal pile and combined pile foundation
By introducing a stress buffer surface and a reinforced skeleton cage between the polygonal pile section body and the cylindrical connecting section, the problems of difficulty in the construction of precast concrete square piles and insufficient contact area are solved, and the pile body bearing capacity and construction efficiency are improved.
Patent Information
- Application Number
- CN202422215301.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-10
- Publication Date
- 2025-08-01
- Estimated Expiration
- 2034-09-10
AI Technical Summary
There are difficulties in correcting the existing precast concrete piles during construction, and the problems of waste of materials and working hours, and the area of contact between the pile and the soil is insufficient, resulting in insufficient vertical bearing capacity.
The stress buffer surface is used to transition the polygonal pile segment body with the cylindrical connecting segment, increasing the contact area between piles and soil, and improving the bearing capacity and construction alignment of the pile body through the steel frame cage and pile hoop.
The vertical bearing capacity of polygonal piles is not reduced, the construction is simple to align, the contact area between piles and soil increases, the pile body performance is improved, the stress concentration is avoided, and the construction quality and efficiency are improved.
Smart Images
Figure CN223176711U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of construction engineering, in particular to a precast concrete polygonal pile and a composite pile foundation. Background Art
[0002] Precast concrete piles have the advantages of high pile body bearing capacity, stable quality, economic efficiency, good durability, and environmental protection on site, and are widely used in industrial and civil buildings, railways, highways, municipal engineering and other fields. With the acceleration of urban construction and the engineering requirements to meet complex and changeable geological conditions, the types of precast concrete piles have developed numerous and diverse shapes, but currently, circular and square outer contours are still the most common. The precast pile with a circular outer contour is widely used because of its uniform stress distribution and excellent performance and stability when the pile body bears vertical or horizontal loads. Its main pile type is the centrifugal concrete pipe pile. Compared with the circular cross-section, there are also precast piles with a square cross-section, mainly including solid square piles and hollow square piles. When using a square pile with the same numerical value of side length and pipe pile diameter, its outer perimeter is larger. When used as a friction pile in soft soil areas, the contact area between the outside of the pile and the soil layer is larger, and the vertical side resistance obtained is greater. However, the following problems exist in the construction of polygonal piles. Taking the square pile as an example, (1) When the square pile is driven into the ground for pile splicing, the two piles need to be aligned. In actual construction, there will be a deviation between the upper and lower piles and they cannot be completely aligned, making alignment difficult; (2) When the square pile is connected to the upper concrete pile cap, there are standard regulations for the minimum distance between the four edges of the square pile and the pile cap. If the side of the square pile is not parallel to the concrete pile cap, in order to meet the current standard regulations, the size of the pile cap needs to be increased, consuming materials and man-hours. As Figure 1 Shown is a schematic diagram of normal construction when the square pile is connected to the pile cap, where L3 meets the standard regulations, Figure 2 In the middle is a schematic diagram of the connection between the square pile and the pile cap during abnormal construction. When the size of the pile cap remains unchanged, L3 meets the standard regulations, and the size of the pile cap needs to be increased. Summary of the Utility Model
[0003] Aiming at the deficiencies existing in the prior art, the utility model provides a precast concrete polygonal pile, which uses a stress buffer surface to connect the polygonal pile section and the cylindrical connection section. While not reducing the vertical bearing capacity of the polygonal pile, it can increase the contact area between the pile and the soil, reduce the stress concentration at the four corners of the polygonal pile, and facilitate construction alignment.
[0004] The utility model realizes the above technical purpose through the following technical means.
[0005] A precast concrete polygonal pile, with a circular steel reinforcement cage arranged inside the pile body. The pile body includes continuous polygonal pile segments and cylindrical connecting segments provided at both ends of the polygonal pile segments; a stress buffer surface is provided between the polygonal pile segments and the cylindrical connecting segments for transitional connection; the horizontal included angle between the stress buffer surface and the cross-section of the pile is 45° ≤ β < 90°.
[0006] Preferably, the horizontal included angle between the stress buffer surface and the cross-section of the pile is 45° ≤ β ≤ 55°.
[0007] Preferably, the cross-section of the cylindrical connecting segment is the inscribed circle of the cross-section of the polygonal pile segment, and the length L1 of the cylindrical connecting segment < a.
[0008] Preferably, the outer diameter of the cylindrical connecting segment is larger than the diameter of the steel reinforcement cage and smaller than the diameter of the inscribed circle of the polygonal pile segment.
[0009] Preferably, a pile sleeve hoop is provided on the cylindrical connecting segment.
[0010] Preferably, the diameter of the steel reinforcement cage is 0.75 - 0.90 times the diameter of the inscribed circle of the cross-section of the polygonal pile segment.
[0011] Preferably, the stress buffer surface is in an inverted triangle shape, the bottom edge of the triangle is the tangent line of the cylindrical connecting segment or the contour line of the cylindrical connecting segment, and the vertex of the triangle corresponding to the bottom edge is arranged on the edge of the polygonal pile segment.
[0012] Preferably, the stress buffer surface is an outer arc convex surface.
[0013] Preferably, there are multiple stress buffer surfaces, which are respectively arranged at the corners of one end where the polygonal pile segment and the cylindrical connecting segment are connected.
[0014] Preferably, at least one surface of the polygonal pile segment is provided with a grouting groove.
[0015] Preferably, the steel reinforcement cage includes main reinforcement bars and spiral stirrups. The main reinforcement bars are grouped and arranged circularly and evenly, and each group of main reinforcement bars includes at least two main reinforcement bars.
[0016] Preferably, each group of main reinforcement bars is distributed at the corners of the polygonal pile segment.
[0017] A combined pile foundation includes the above-mentioned precast concrete polygonal pile. The sides of the upper precast concrete polygonal pile and the lower precast concrete polygonal pile are staggered, and the edges of the upper precast concrete polygonal pile protrude from the sides of the corresponding lower precast concrete polygonal pile.
[0018] Preferably, the angular bisector of the upper precast concrete polygonal pile coincides with the midline on the side of the lower precast concrete pile.
[0019] The utility model has the following beneficial effects:
[0020] (1) The utility model has the characteristics of simple structure, high bearing capacity, novel and beautiful shape, high production efficiency, etc. The pile body performance is equivalent to that of the existing conventional multi-sided piles. The end of the polygon pile is adjusted to a circular shape, and deviation correction can be effectively carried out during pile splicing. As long as the two pile heads are aligned, it is not necessary to align all the surfaces of the upper and lower two piles; when connecting the pile with the bearing platform, regardless of whether the pile is inclined (the inclination means that the side surface of the square section of the pile is not parallel to the edge of the bearing platform, rather than the pile body being inclined relative to the horizontal plane), as long as the center of the pile meets the requirements (the pile is perpendicular to the horizontal plane), the distance from the pile end to the bearing platform can meet the requirements.
[0021] (2) The utility model adjusts the end of the polygon pile from a polygon to a circular shape, and then adopts a stress buffer surface for transition, effectively releasing the stress during the construction process, which diffuses from the four sides to each buffer surface, improving the quality of the precast pile after construction. The reduced contact area between the pile body and the soil at the end is compensated by the stress buffer surface, increasing the contact area between the pile and the soil and ensuring the vertical bearing capacity of the pile.
[0022] (3) The utility model adjusts the end of the polygon pile from a polygon to a circular shape. When using hammering construction, the force on the pile end is more uniform, effectively avoiding the stress concentration phenomenon at the pile corners. Description of the Drawings
[0023] Figure 1 It is a schematic diagram of normal construction when connecting a square pile with a bearing platform in the background technology;
[0024] Figure 2 It is a schematic diagram of connecting a square pile with a bearing platform during abnormal construction in the background technology;
[0025] Figure 3 It is a schematic diagram of the structure of the precast concrete polygon pile of the utility model;
[0026] Figure 4 For Figure 3 The schematic diagram of the steel cage layout;
[0027] Figure 5 It is the front view of the precast concrete polygon pile of the utility model;
[0028] Figure 6 It is a schematic diagram of the structure of the precast concrete polygon pile in Embodiment 2;
[0029] Figure 7 It is a schematic diagram of the steel cage layout in Embodiment 3;
[0030] Figure 8 It is a schematic diagram of the steel cage layout in Embodiment 3;
[0031] Figure 9 Schematic structural diagram of the precast concrete polygonal pile of Example 4;
[0032] Figure 10 For Figure 9 Schematic diagram of grouting grooves arranged on the overlooking opposite faces;
[0033] Figure 11 For Figure 9 Schematic diagram of grouting grooves arranged on the overlooking adjacent faces;
[0034] Figure 12 For Figure 10 Schematic diagram of the straight connection method of the precast polygonal concrete pile in;
[0035] Figure 13 For Figure 11 Schematic diagram of the corner connection method of the precast polygonal concrete pile in;
[0036] Figure 14 Schematic structural diagram of the combined pile foundation;
[0037] Figure 15 For Figure 14 Top view.
[0038] Reference numerals:
[0039] 1 - Polygonal pile segment; 1 - 1 - Grouting groove; 2 - Cylindrical connection segment; 3 - Steel bar cage; 3 - 1 - Main reinforcement; 3 - 2 - Helical stirrup; 4 - Stress buffer surface; 4 - 1 Upper contour line; 4 - 2 - Lower contour line; 5 - Pile sleeve hoop; 6 - Sealing material; 7 - Upper precast concrete square pile; 8 - Lower precast concrete square pile; 9 - Cap; 10 - Square pile. Detailed implementation manners
[0040] The embodiments of the present invention will be described in detail below. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present invention, and should not be construed as a limitation to the present invention.
[0041] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "axial", "radial", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present utility model, the meaning of "a plurality" is two or more, unless otherwise specifically defined.
[0042] In the present utility model, unless otherwise clearly specified and defined, terms such as "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.
[0043] Embodiment 1
[0044] Combined with the attached Figure 3 and 4 As shown, a precast concrete polygonal pile is provided with a circular steel bar cage 3 inside the pile body. The pile body includes a polygonal pile segment body 1 and cylindrical connection segments 2 provided at both ends of the polygonal pile segment body. The polygonal pile segment body 1 and the cylindrical connection segments 2 are connected through a stress buffer surface 3. The cross-section of the cylindrical connection segment 2 is slightly smaller than the inscribed circle of the cross-section of the polygonal pile segment body. A pile sleeve hoop 5 is provided on the cylindrical connection segment 2. As Figure 5 shown, the horizontal angle β between the stress buffer surface 3 and the pile cross-section satisfies 45° ≤ β < 90°. In this angle range, the length of the stress buffer surface (where a is the side length of the pile segment of the polygonal pile segment body) makes the pile driving resistance received by the pile during the pile driving process small and the disturbance to the soil body smaller;
[0045] Subject to
[0046] The length L1 of the cylindrical connecting section is < a because the cylindrical connecting section is used for connecting the upper and lower precast piles and plays a role in connecting the upper and lower parts. When the length of the cylindrical connecting section is too long, it is equivalent to shrinking the polygon into an inscribed circle, reducing the side resistance of the polygonal pile. Controlling the length of the cylindrical connecting section within the range of 1 times the side length can effectively control the loss of the bearing capacity of the original polygonal pile. The cylindrical connecting section 2 is located at the end of the polygonal pile section. From the cross-section view, the cylindrical connecting section is tangent to the polygonal pile section. While not changing the vertical bearing capacity of the pile, it increases the contact area between the pile and the soil, facilitating pile connection alignment and controlling the area between the pile and the pile cap.
[0047] When 45° ≤ β ≤ 55°, the length of the stress buffer surface The length L2 within this range can effectively reduce the loss of side resistance at the cylindrical connecting section.
[0048] As Figure 3 shown, when the polygonal pile section is a square pile, there are 4 stress buffer surfaces, which are respectively placed at the corners of one end where the polygonal pile section and the cylindrical connecting section are connected. The stress buffer surface 4 is in an inverted triangle shape, including an upper contour line 4-1 and a lower contour line 4-2. The upper contour line 4-1 is the contour line of the cylindrical connecting section corresponding to the corner of the square pile, and the lower contour line 4-2 is set on two adjacent side surfaces of the square pile section 1. The lower contour line 4-2 is an outwardly convex arc. The stress buffer surface surrounded by the upper contour line 4-1 and the lower contour line 4-2 is an outwardly convex arc surface, increasing the contact area between the pile and the soil mass, thereby increasing the frictional force and uplift resistance.
[0049] As Figure 4 shown, the steel reinforcement cage 3 includes uniformly distributed main reinforcements 3-1 and spiral stirrups 3-2, and the main reinforcements 3-1 are arranged along the entire pile length. The diameter of the cylindrical connecting section 2 is larger than the diameter of the steel reinforcement cage 3 and smaller than the diameter of the inscribed circle of the pile section of the polygonal pile section; the main reinforcements 3-1 are arranged along the entire pile length to achieve full-length tensioning, with better force. If the diameter of the cylindrical connecting section 2 is smaller than the diameter of the steel reinforcement cage 3, it will cause the cylindrical connecting section to be unable to achieve prestress tensioning (similar to the pile tip of a pencil pile having no prestress), affecting the overall mechanical properties of the pile body.
[0050] Preferably, the diameter of the steel reinforcement cage 3 is 0.75 - 0.90 times the diameter of the inscribed circle of the cross-section of the polygonal pile section. If the diameter of the steel reinforcement cage is too large, the concrete cover thickness of the steel bars will not meet the anti-corrosion requirements. If the diameter of the steel reinforcement cage is too small, it is not conducive to the restraint of the concrete at the corners of the polygonal pile.
[0051] Embodiment 2
[0052] As Figure 6As shown, in this embodiment, the stress buffer surface 4 includes an upper contour line 4-1 and a lower contour line 4-2. The upper contour line is the tangent of the cylindrical connection segment contour line corresponding to the corner of the square polygon segment. The lower contour line 4-2 is arranged on two adjacent sides of the polygon pile segment body 1. The projection of the contour line of the square pile end body between the upper contour line 4-1 and two adjacent upper contour lines 4-1 on the horizontal plane is octagonal. The cylindrical connection segment is the inscribed circle of this octagon, ensuring that the stress received during hammering is evenly distributed to each surface. Other structures are the same as those in Embodiment 1.
[0053] Embodiment 3
[0054] When the number of steel bars is large, if the main steel bars 3-1 are still arranged evenly as usual, it will cause the gravel in the concrete to be unable to pass through the steel bar cage, affecting the final strength of the pile body concrete. Combining with the attached Figure 7 As shown, the steel bar cage 3 includes main steel bars 3-1 and spiral stirrups 3-2. The main steel bars 3-1 are arranged in groups in a circular and uniform manner, and the spacing between adjacent groups is increased to facilitate the gravel to pass through. As Figure 8 shown, each group of main steel bars is distributed at the corners of the polygon pile segment body. This arrangement structure can not only avoid the situation that the gravel in the concrete cannot pass through the steel bar cage due to too dense steel bars, affecting the final strength of the pile body concrete, but also increase the concrete stress at the four corners of the square segment pile body, enhancing the protection ability of the pile head during hammering construction. Other structures are the same as those in Embodiment 1.
[0055] Embodiment 4
[0056] Combining with the attached Figures 9 to 13 As shown, a precast concrete polygon pile includes a polygon pile segment body 1, two cylindrical connection segments 2, and a steel bar cage 3. The polygon pile segment body 1 and the cylindrical connection segments 2 are connected through a stress buffer surface 4. At least one grouting groove 1-1 (in this embodiment, two arc-shaped grouting grooves, and the cross-sectional shape of the grouting groove can also be trapezoidal) is provided on at least one surface of the polygon pile segment body 1. When used in a support project, the grouting groove 5 can be filled with a sealing material 6 after the precast pile is sunk, which has the functions of water stop and soil retention.
[0057] Combining with the attached Figure 10 and 12 shown, among which, Figure 12 is a schematic diagram of a precast concrete polygon pile with grouting grooves provided on opposite surfaces; when grouting grooves 5 are provided on the opposite surfaces of two polygon pile segment bodies 1, it is mainly used for the splicing of straight segments.
[0058] Combining with the attached Figure 11 and 13 shown, among which, Figure 13Schematic diagram of a grouting groove arranged on adjacent faces of a precast concrete polygonal pile; when grouting grooves 1-1 are arranged on adjacent faces of two polygonal pile segments 1, it is mainly used for splicing at the corner segment. The cross-sections of the polygonal pile segment and the cylindrical connecting segment can also be solid cross-sections, and other structures are the same as those in Embodiment 1.
[0059] Embodiment 5
[0060] The sides of the upper precast concrete polygonal pile and the lower precast concrete polygonal pile are staggered, and the edges of the upper precast concrete polygonal pile protrude from the sides of the corresponding lower precast concrete polygonal pile.
[0061] Combined with the attached Figure 14 、 15 As shown, taking a square pile as an example, when the end is set to be circular, by adjusting the cross-section direction of the precast concrete square pile, the combination shown in the following figure can be formed (that is, the lower precast concrete square pile 8 and the upper precast concrete square pile 7 are misaligned). After the lower precast concrete square pile 8 and the upper precast concrete square pile 7 are connected, the whole pile forms a "convex" shape. At this time, when used for uplift resistance, the square pile is in a stress state from bottom to top. Due to the effect of the convex platform of the lower precast concrete square pile, the contact area with the soil on the pile side is increased, and more surrounding soil can be driven, so the uplift bearing capacity obtained is higher (that is, the uplift coefficient is higher).
[0062] The angular bisector of the upper precast concrete polygonal pile coincides with the midline on the side of the lower precast concrete pile. In this case, the perimeter at the joint of the two piles is the largest, so the contact area between the pile and the soil is the largest. The protruding part can also receive the vertical force from the soil above, and the uplift resistance effect is better. If both the upper and lower piles are square, the upper pile needs to be rotated 45° relative to the lower pile. If both the upper and lower piles are triangular, the upper pile needs to be rotated 60°.
[0063] In the above embodiments, the polygonal pile segment 1 can be a hollow pile segment or a solid pile segment, and the cylindrical connecting segment can be a solid pile segment or a hollow pile segment.
[0064] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.
[0065] Although the embodiments of the present utility model have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present utility model. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present utility model without departing from the principles and spirit of the present utility model.
Claims
1. A precast concrete polygonal pile, characterized in that, A circular steel bar cage is provided inside the pile body. The pile body includes continuous polygonal pile segments and cylindrical connecting segments provided at both ends of the polygonal pile segments; a stress buffer surface is used for transitional connection between the polygonal pile segments and the cylindrical connecting segments; the horizontal angle β between the stress buffer surface and the cross-section of the pile satisfies 45° ≤ β < 90°.
2. The precast concrete polygonal pile according to claim 1, characterized in that, The horizontal angle β between the stress buffer surface and the cross-section of the pile satisfies 45° ≤ β ≤ 55°.
3. The precast concrete polygonal pile according to claim 1, characterized in that, The cross-section of the cylindrical connecting segment is the inscribed circle of the cross-section of the polygonal pile segment, and the length L1 of the cylindrical connecting segment is less than a.
4. The precast concrete polygonal pile according to claim 1, wherein The outer diameter of the cylindrical connecting segment is larger than the diameter of the steel bar cage and smaller than the diameter of the inscribed circle of the polygonal pile segment.
5. The precast concrete polygonal pile according to claim 4, wherein A pile sleeve hoop is provided on the cylindrical connecting segment.
6. The precast concrete polygonal pile according to claim 4, wherein The diameter of the steel bar cage is 0.75 to 0.90 times the diameter of the inscribed circle of the cross-section of the polygonal pile segment.
7. The precast concrete polygonal pile according to claim 1, wherein The stress buffer surface is in the shape of an inverted triangle. The bottom edge of the triangle is the tangent line of the cylindrical connecting segment or the contour line of the cylindrical connecting segment, and the vertex of the triangle corresponding to the bottom edge is provided on the edge of the polygonal pile segment.
8. The precast concrete polygonal pile according to claim 6, characterized in that, The stress buffer surface is an outwardly arcuate convex surface.
9. The precast concrete polygonal pile according to claim 1, wherein There are multiple stress buffer surfaces, which are respectively placed at the corners of one end where the polygonal pile segment and the cylindrical connecting segment are connected.
10. The precast concrete polygonal pile according to claim 1, characterized in that, At least one surface of the polygonal pile segment is provided with a grouting groove.
11. The precast concrete polygonal pile according to claim 1, wherein The steel bar cage includes main bars and spiral stirrups. The main bars are grouped and arranged circularly and longitudinally. Each group of main bars includes at least two main bars.
12. The precast concrete polygonal pile according to claim 11, wherein, Each group of main bars is distributed at the corners of the polygonal pile segment.
13. A combined pile foundation, comprising the precast concrete polygonal pile according to any one of claims 1-12, characterized in that, The sides of the upper precast concrete polygonal pile and the lower precast concrete polygonal pile are staggered. The edges of the upper precast concrete polygonal pile protrude from the corresponding sides of the lower precast concrete polygonal pile.
14. The combined pile foundation according to claim 13, wherein: The angle bisector of the upper precast concrete polygonal pile coincides with the midline on the side of the lower precast concrete pile.