CN216787114U

CN216787114U - A concrete high strength precast pile head structure for bored concrete pile

Info

Publication number: CN216787114U
Application number: CN202123059791.XU
Authority: CN
Inventors: 胡达敏; 李保忠; 任光勇; 汪光满; 谢道清; 钟舟能
Original assignee: Zhejiang Gad Co ltd
Current assignee: Zhejiang Gad Co ltd
Priority date: 2021-12-07
Filing date: 2021-12-07
Publication date: 2022-06-21
Anticipated expiration: 2031-12-07

Abstract

The utility model discloses a concrete high-strength precast pile head structure of a cast-in-situ bored pile, which comprises a pile head body and is characterized in that the pile head body is of a cone frustum structure with a large upper part and a small lower part, and the upper half section of the pile head body is provided with a cylinder length section; a plurality of vertical steel bars which are vertically arranged and have threads at the upper ends are arranged in the pile head body; a steel bar framework is arranged in the pile head body, and the top surface is a cambered surface with a high middle part and a low periphery; a plurality of vertical through reserved vertical holes are also arranged in the pile head body. The method meets the technical requirements of extrusion cutting, thereby ensuring that the bottom surface of the pile head is tightly connected with the bearing layer, solving the problem of controlling the sediment of the cast-in-situ bored pile, improving the pile forming quality of the cast-in-situ bored pile, effectively ensuring the bearing performance of the cast-in-situ bored pile, simplifying sediment control measures in the construction process and reducing the construction cost; the system can be standardized and customized in factories, and accords with industrial and assembly type building policies; it is suitable for various cast-in-place piles such as impact hole forming, rotary drilling hole forming and the like.

Description

Concrete high-strength precast pile head structure for cast-in-situ bored pile

Technical Field

The utility model relates to the building engineering technology, in particular to a concrete high-strength precast pile head structure for a cast-in-situ bored pile.

Background

The bored pile is used as a pile foundation for supporting main buildings from short buildings in soft soil areas to super high-rise buildings with good foundation soil layers, and the bored pile can provide various bearing capacities meeting requirements through the change of the diameter and the pile length. In this cast-in-situ bored pile construction method, in addition to the assurance of material properties, a very important quality control factor is the control of the sediment at the bottom end of the pile. During drilling, the drilling machine cuts the side wall and the bottom (rock) soil layer of the hole to generate muck, most of the muck is carried out of the ground during drilling and hole forming, and some muck is still deposited at the bottom of the hole. In addition, in the higher geology of groundwater level, the pore wall often needs to have the mud of certain consistency to carry out the dado to prevent to creep into the in-process pore wall and collapse, put the steel reinforcement cage and put the in-process that the pipe poured concrete at the drilling completion, mud all can produce the deposit of certain degree along with the continuation of construction time, forms the sediment at the bottom of the hole. When the hole bottom sediments reach a certain thickness, the bearing capacity of the end part of the cast-in-place pile is adversely affected, the bearing capacity of the pile is obviously reduced, and the safety of the building is affected.

The bottom end of the cast-in-place pile is very large, a loose and soft sediment layer with obvious thickness can exist, and the method is particularly easy to appear in a rock-socketed cast-in-place pile foundation with a deep and long bored cast-in-place pile in soft soil geology and a mud rock layer as a bearing stratum, and is easy to cause thick mud deposition because the time for hoisting a reinforcement cage and preparing concrete for pouring is long after the deep and long pile is formed into a hole; when the pile end bearing layer is underwater argillaceous rock, argillaceous debris cut by drilling has strong cementing capacity, a mud-shaped block body is formed, and the mud-shaped block body is not easy to be discharged by cleaning holes; subsequent concrete impact and pile end grouting have good treatment effect on loose granular sediments, but lose effect on daub-shaped sediments.

Disclosure of Invention

The utility model aims to solve the problems and provides a concrete high-strength precast pile head structure for a cast-in-situ bored pile, which is matched with a reinforcement cage to be placed at the bottom end of a pile body, and enters bottom sediment in an extrusion cutting mode under the action of the weight of the reinforcement cage and the like, so that the bottom surface of the pile head is tightly connected with a bearing layer, the pile forming quality of the cast-in-situ bored pile is improved, and the bearing performance of the cast-in-situ pile is ensured.

The technical problem of the utility model is mainly solved by the following technical scheme: a concrete high-strength precast pile head structure for a cast-in-situ bored pile comprises a pile head body, and is characterized in that the pile head body is of a cone frustum structure with a large upper part and a small lower part, and the upper half section is provided with a cylinder length section; a plurality of vertical steel bars which are vertically arranged and have threads at the upper ends are arranged in the pile head body; a steel bar framework is arranged in the pile head body, and the top surface is a cambered surface with a high middle part and a low periphery; a plurality of vertical through reserved vertical holes are also formed in the pile head body.

In the concrete high strength precast pile head structure for bored concrete pile, as preferred, with the supporting steel bar connector that is equipped with of vertical reinforcing bar, steel bar connector are straight thread sleeve structure, and steel bar connector is pre-buried in pile head body top surface.

In the concrete high-strength precast pile head structure for the cast-in-situ bored pile, preferably, the maximum diameter of the pile head body is equal to the designed diameter of the pile body of the cast-in-situ bored pile.

In the concrete high-strength precast pile head structure for the cast-in-situ bored pile, preferably, the height of the projection of the central point of the arc surface of the pile head body is one tenth of the designed pile diameter.

In the concrete high-strength precast pile head structure for the cast-in-place bored pile, preferably, the bottom shape of the pile head body is the same as the shape of a drill bit of a cast-in-place pile drilling machine.

In the concrete high-strength precast pile head structure for the cast-in-situ bored pile, preferably, the reserved vertical holes are symmetrically arranged in the pile head body according to the center of the pile head.

In the concrete high-strength precast pile head structure for the cast-in-situ bored pile, preferably, the plurality of vertical steel bars and the steel bar connectors are uniformly arranged on the circumference of the same diameter; the reserved vertical hole is arranged in the center area of the pile head body, and the distance between the center of the reserved vertical hole and the center of the pile head is not more than 0.35 time of the maximum diameter of the pile head body.

In the concrete high strength precast pile head structure for bored concrete pile, as preferred, steel reinforcement framework is including the top surface muscle that is located this internal upper portion of pile head, constitutes the hoop muscle of the radial basic skeleton of pile head body to and the vertical muscle of arranging along pile head body axial.

The technical scheme designs a high-strength concrete prefabricated pile head which is consistent with a drill bit of a bored concrete pile drilling machine in shape, and a pile head body is in a cone frustum shape, is large at the top and small at the bottom, is slightly sharp at the bottom and is easy to extrude and cut. The cylinder length section of first half can satisfy arranging of vertical reinforcing bar, also makes the pile head body have abundant volume. Pile head body adopts high-grade concrete placement, and inside configuration steel skeleton forms a high strength entity, through conventional analytical design, can guarantee to arrange vertical through reservation vertical cavity simultaneously, still has sufficient resistance to compression bearing capacity, satisfies pile foundation bottom and bears the requirement.

Pile head top surface is equipped with straight thread sleeve formula steel reinforcement connector, can be connected as a whole with pile body steel reinforcement cage through simple operation, makes things convenient for the building site to connect, and the hoist and mount are transferred. The steel bar connector is embedded in the top surface of the pile head body, and the screw is flush with the top surface of the pile head body, so that the phenomenon that the pile head body is damaged by extrusion in the transportation process is avoided.

The diameter of the pile head body is the same as the designed diameter of the pile body of the cast-in-place pile, so that the shape of the bottom surface of the pile head is close to that of the bottom surface of the hole drilled with the hole and the bottom surface of the hole is matched with the bottom surface of the hole. The top surface is of a micro arc structure with a high middle part and a low periphery, when concrete pouring is carried out after hole cleaning, when the first bucket of concrete impacts the pile head, a small amount of sediment possibly remaining on the top surface of the pile head is flushed to the periphery of the pile head along the arc surface of the top part of the pile head, and falls into a side gap between the prefabricated pile head and a drilled hole after being mixed with concrete cement slurry, so that the concrete in the range of the pile head is better ensured not to be clamped with sediment, and excellent pouring quality is realized.

The device is reasonably arranged to reserve the vertical holes, so that all directions in the process of lowering the pile head can benefit, on one hand, the hydraulic resistance in the lowering process can be reduced, and on the other hand, the pile head can be favorably cut into the sediment at the bottom of the hole. The pile head structure can ensure that the sediment at the bottom of the hole is extruded into the reserved vertical hole or the peripheral gap of the pile head, thereby ensuring that the pile head is tightly attached to a bearing (rock) soil layer. After the pile head is put in place, newly-deposited sediments are also isolated on the upper surface of the pile head body when the concrete guide pipe is placed, the situation that the sediments are accumulated to the bottom of the hole to increase the thickness of the sediments at the bottom of the hole like a conventional cast-in-place pile can not occur, and the secondary hole cleaning and sediment reduction by utilizing the concrete guide pipe are very favorable, so that the sediment accumulation effect in the construction process is reduced, and the hole cleaning and sediment reduction effect is improved.

According to the design idea of the scheme, the device can set the pile head basic data according to standardization so as to realize good universality and interchangeability, and if the number of the steel bar connectors in the pile head can be set to be in a standard specification according to the diameter of the pile head, the pile head can be prefabricated in a standardized batch mode. When the number of the longitudinal bars of the pile body reinforcement cage is different from the number of the reinforcement connectors, the pile heads with the same diameter but different reinforcement arrangements can adopt the same specification by a partial longitudinal bar connection mode, and the industrialized processing and the field construction are facilitated.

The utility model has the beneficial effects that: the basic pile head structure which has the same shape as the drill bit of the cast-in-place pile drilling machine and the design of the reserved vertical hole meet the technical requirements of extrusion cutting, so that the bottom surface of the pile head is ensured to be tightly connected with the bearing layer, the problem of controlling the sediment of the cast-in-place pile is solved, the pile forming quality of the cast-in-place pile is improved, the bearing performance of the cast-in-place pile is effectively ensured, the sediment control measures in the construction process are simplified, and the construction cost is reduced; the system can be standardized and customized in factories, and accords with industrial and assembly type construction policies; it is suitable for various cast-in-place piles such as impact hole forming, rotary drilling hole forming and the like.

Drawings

FIG. 1 is a schematic diagram of an embodiment of the present invention.

Fig. 2 is a schematic diagram of an internal structure of the present invention.

Fig. 3 is a schematic view of the structure in the direction of a-a of fig. 1.

Fig. 4 is a top view of fig. 1.

Fig. 5 is a schematic view of a partial enlarged structure at M in fig. 1.

Fig. 6 is a schematic structural diagram of a use state of the present invention.

In the figure: 1. the pile head comprises a pile head body, 2 vertical steel bars, 3 steel bar connectors, 4 steel bar frameworks, 401 top gluten, 402 vertical bars, 403 annular tendons, 5 reserved vertical holes, 6 holding force (rock) soil layers and 7 steel bar cages.

Detailed Description

The technical scheme of the utility model is further specifically described by the following embodiments and the accompanying drawings.

The embodiment is a concrete high strength precast pile head structure for bored concrete pile, refer to fig. 1 to 4, design pile head body 1 of big-end-up small cone structure, the first half of pile head body 1 has a section of cylinder length section, be equipped with a set of vertical layout in pile head body 1, and the vertical reinforcement 2 of the 1 top surface of pile head body is worn out to the upper end, the cylinder length section of first half is according to

vertical reinforcement

2, and 3 configuration demands of steel bar connector combine the stake footpath to confirm, get length 250 ~ 400 mm. Pile head body 1 adopts high grade concrete placement, embeds framework of steel reinforcement 4, constitutes high strength pressure-resistant whole. The top surface of the pile head body 1 is a cambered surface with a high middle part and a low periphery. Still be equipped with a set of vertical through-going vertical hole 5 of reserving in the pile head body 1, the area of reserving vertical hole 5 and setting up is not more than 5% of pile head plane projection area.

The maximum diameter of the pile head body 1 is equal to the designed diameter of the pile body of the cast-in-place pile, and the bottom shape of the pile head body is the same as the shape of a drill bit of a cast-in-place pile drilling machine. With 2 supporting steel bar connectors 3 that are equipped with of vertical reinforcing bar, steel bar connectors 3 are straight thread sleeve structure, and steel bar connectors 3 are pre-buried in 1 top surface of pile head body, as shown in fig. 5, its screw socket flushes with 1 top surface of pile head body, covers the screw socket with protecting the stopper before the installation.

Specifically, the height of the projection of the center point of the arc surface of the pile head body 1 is one tenth of the designed pile diameter, and the projection is in a micro arc shape. All the vertical steel bars 2 and the steel bar connectors 3 are uniformly distributed on the circumference with the same diameter; the reserved vertical hole 5 is arranged in the central area of the pile head body 1, the distance between the center of the reserved vertical hole 5 and the center of the pile head is not more than 0.35 time of the maximum diameter of the pile head body 1, and the reserved vertical hole 5 is symmetrically arranged in the pile head body 1 according to the center of the pile head.

The steel bar framework 4 mainly comprises a top surface rib 401, a vertical rib 402 and a circumferential rib 403, wherein the top rib 401 is positioned at the upper part in the pile head body 1, a grid structure is formed by steel bars, and a reserved vertical hole 5 is reserved; the circumferential ribs 403 form a radial basic framework of the pile head body 1, and the vertical ribs 402 are arranged along the axial direction of the pile head body and connected with the jacking ribs 401 and the circumferential ribs 403 to form a whole. In practical applications, the vertical reinforcement 2 can be applied together with the vertical reinforcement 402 at a proper position.

During the use, this pile head passes through connector for reinforcement 3 and is connected as whole with pile body steel reinforcement cage, as shown in fig. 6, indulges when muscle quantity is greater than connector for reinforcement 3 quantity when the pile body of pile body steel reinforcement cage, then partial pile body indulge the muscle be connected with connector for reinforcement 3 can, generally regard as with interval or evenly distributed, remaining pile body indulges the muscle and withstands the top surface of pile head body 1.

Drilling and pile forming: after drilling and first hole cleaning are completed, a reinforcement cage connected with a prefabricated pile head (comprising a pile head body 1, the same below) is hoisted and laid down, and the lengthening and laying processes of the reinforcement cage are performed according to a traditional method. When the prefabricated pile head is placed to the bottom of the drilled hole and is blocked, the height mark can be rechecked through depth dimension monitoring and hole forming, and the sediment thickness and distribution condition of the bottom surface of the prefabricated pile head can be more accurately evaluated by considering the dimension factors of the drill bit and the pile head. Under the action of the weight of the upper reinforcement cage, the prefabricated pile head with a conical structure can be more easily extruded and cut into the bottom sediment by opening the hole by the pile head, so that the bottom surface of the prefabricated pile head is more closely connected with the bearing (rock) soil layer 6, and the weight of subsequent concrete pouring is also favorable for compaction.

And after the prefabricated pile head and the reinforcement cage are put in place, putting concrete into the top surface of the pile head, and performing secondary hole cleaning by using the guide pipe. Because the setting of precast pile head makes the pipeline transfer in-process sediment of latest deposit by keeping apart at pile head upper surface, can not fuse together with bottom sediment, then the secondary clear hole that utilizes concrete placement pipe to go on can realize better scarfing cinder effect, can fine control the sediment of precast pile head upper surface.

Along with the increase of the concrete pouring amount, the precast pile head is further extruded downwards under the action of the weight of the concrete, sediment possibly remaining on the bottom surface of the precast pile head is distributed more dispersedly, and the corresponding thickness is smaller, so that the pile body can be squeezed more closely, and the close contact between the concrete of the pile body and the bearing (rock) soil layer 6 is ensured.

The above embodiments are illustrative of the present invention, and are not intended to limit the present invention, and any simple modifications of the present invention are within the scope of the present invention.

Claims

1. A concrete high-strength precast pile head structure for a cast-in-situ bored pile comprises a pile head body (1) and is characterized in that the pile head body is of a circular truncated cone structure with a large upper part and a small lower part, and the upper half section is provided with a cylinder length section; a plurality of vertical steel bars (2) which are vertically arranged and have threads at the upper ends are arranged in the pile head body; a steel bar framework (4) is arranged in the pile head body, and the top surface is a cambered surface with a high middle part and low periphery; a plurality of vertical through reserved vertical holes (5) are also arranged in the pile head body.

2. The concrete high-strength precast pile head structure for the cast-in-situ bored pile according to claim 1, wherein a steel bar connector (3) is provided in cooperation with the vertical steel bar (2), the steel bar connector is of a straight thread sleeve structure, and the steel bar connector is embedded in the top surface of the pile head body (1).

3. The concrete high-strength precast pile head structure for the cast-in-situ bored pile according to claim 1, wherein the maximum diameter of the pile head body (1) is equal to the designed diameter of the pile body of the cast-in-situ bored pile.

4. The concrete high-strength precast pile head structure for the cast-in-situ bored pile according to claim 1, wherein the height of the projection of the center point of the arc surface of the pile head body (1) is one tenth of the designed pile diameter.

5. The concrete high-strength precast pile head structure for bored pile according to claim 1, characterized in that the bottom shape of the pile head body (1) is the same as the shape of the drill bit of bored pile drilling machine.

6. The concrete high-strength precast pile head structure for the cast-in-situ bored pile according to claim 1, wherein the plurality of reserved vertical holes (5) are symmetrically arranged in the pile head body (1) according to the center of the pile head.

7. The concrete high-strength precast pile head structure for the cast-in-situ bored pile according to claim 2, wherein the plurality of vertical steel bars (2) and the steel bar connectors (3) are uniformly arranged on the same diameter circumference; the reserved vertical hole (5) is arranged in the central area of the pile head body (1), and the distance between the center of the reserved vertical hole and the center of the pile head is not more than 0.35 time of the maximum diameter of the pile head body.

8. The concrete high-strength precast pile head structure for the cast-in-situ bored pile according to claim 1, wherein the steel reinforcement cage (4) comprises a top surface rib (401) located at an upper portion inside the pile head body (1), a circumferential rib (403) constituting a basic cage of the pile head body, and a vertical rib (402) arranged along an axial direction of the pile head body.