CN110424384B

CN110424384B - Large-diameter prefabricated pipe pile and construction method thereof

Info

Publication number: CN110424384B
Application number: CN201910766193.4A
Authority: CN
Inventors: 袁启良; 张光力; 李故新; 石永军; 龚平; 张伦德
Original assignee: Guangdong Sanhe Pile Co Ltd
Current assignee: Guangdong Sanhe Pile Co Ltd
Priority date: 2019-08-19
Filing date: 2019-08-19
Publication date: 2020-12-08
Anticipated expiration: 2039-08-19
Also published as: CN110424384A

Abstract

A large-diameter precast tubular pile and a construction method thereof belong to the technical field of precast tubular piles, and the tubular pile comprises a pile body and a pile foot, wherein the pile foot is annular and comprises an annular end plate and an annular inward-inclined toe; the construction method comprises the steps of positioning, settling, hollowing out a bottom end cavity, constructing a dome-shaped bulge at the bottom of the bottom end cavity, laying a dome-shaped reinforcement cage along the dome-shaped bulge, and then pouring concrete mortar to form a dome-shaped structural substrate below the bottom end of the tubular pile; the pile foot is made into a hollow ring shape, and the outer wall of the pile foot is inclined inwards, so that pile sinking resistance can be greatly reduced, the pipe pile has a self-balancing sinking function, and a pile body is directly and firmly grabbed by lateral soil foundations, so that the construction difficulty is reduced; a dome-shaped bulge is constructed in the center of the cavity at the bottom end, a permeable membrane is covered on the dome-shaped bulge, and a dome-shaped tubular pile substrate is constructed by reinforced concrete, so that the vibration of the bottom can be reduced, the bottom is more stable, and the tubular pile is firmer and firmer on the whole.

Description

Large-diameter prefabricated pipe pile and construction method thereof

Technical Field

The invention relates to the technical field of precast tubular piles, in particular to a large-diameter precast tubular pile and a construction method thereof.

Background

With the rapid development of the economy of China, the construction of various buildings is in the spotlight. The precast tubular pile is widely applied to various pile foundations and foundation treatment projects. Especially in the development of marine island engineering in recent years, the large-diameter tubular pile has obvious reinforcing effect on an island foundation. With the diversification of pile types and construction environments, the improvement of prefabricated pipe pile types and the innovation of construction methods thereof are in endlessly in the domestic industry.

The existing pile-forming method of precast pile mainly includes static pressure method, hammering method, implantation method, middle digging method and vibration method. The static pressure method is to press the precast pile into the ground by utilizing the self gravity of the static pressure pile machine, no noise is generated in the whole pile pressing process, but the required equipment is heavy and is inconvenient to move; the hammering method mainly uses a diesel hammer or a hydraulic hammer to repeatedly hammer the pile top so as to sink the precast pile, has high pile pressing efficiency, but has obvious vibration and larger noise in the construction process and can disturb the stratum so as to influence the environment; the implantation method is widely applied abroad, and comprises the steps of drilling a hole in a stratum through a drilling machine, pouring cement slurry into the hole, and finally implanting the whole precast pile into the hole; the vibration method reduces the resistance between pile soils through the continuous vibration of the vibration hammer, and finally achieves the purpose of pile sinking under the action of gravity.

However, with the increase of high-rise buildings, the static pressure method, the hammering method, the implanting method and the vibration method are not suitable for the engineering construction of precast piles with the characteristics of large diameter (the outer diameter of the pile is more than or equal to 800mm) and large length (the length of the pile is more than or equal to 10m), while the middle digging method belongs to non-soil-squeezing piles, the construction process is more environment-friendly and is suitable for the construction of hollow precast piles with large diameter, so the middle digging method is often adopted for the construction of the precast piles in the current engineering. However, the medium excavation method has the following disadvantages: the precast pile is of an integrally formed structure, and has large volume and heavy weight, a construction system involved in the pile sinking process is numerous and complicated, used equipment and consumed construction cost are high, efficiency is low, and bearing capacity of a pile end is reduced after the pile is formed, so that the specification of the applicable precast pile is greatly limited.

Thus, patent document CN 109024562 a provides a construction method of a long precast tubular pile with a large diameter, which comprises sinking a pile tip of the precast tubular pile into the soil and splitting a pile body of the precast tubular pile into a plurality of hollow pile bodies, realizing non-fixed connection between the pile tip and the pile body and between two adjacent pile bodies in the pile body through a sleeve, performing graded propulsion on the pile tip and each pile body from bottom to top by using a push rod to gradually sink the precast tubular pile, increasing the number of connected pile body sections along with continuous sinking of the precast tubular pile, and after the precast tubular pile meets the construction depth requirement, recovering the push rod and pouring concrete to fill gaps between the pile bodies; the pile tip resistance born by the pile tip and the pile side resistance born by the pile body are separated, the large pile side resistance born by the whole pile body is separated into a plurality of sections of small pile side resistances, the limitation of the existing equipment on the aspect of the construction depth of the precast tubular pile is effectively solved, and the maximum utilization of the equipment is realized.

However, the pile tip adopted by the method has three disadvantages: 1. the resistance borne by the integral pile tip is very large, and the consumed energy is very large; 2. the pile tip structure enables the first contact position of the pipe pile and the soil body to be in a point shape, so that the whole pile tip is easy to deflect during sinking operation, and the pile body cannot feel, thus increasing the engineering difficulty; 3. the outer diameter of the pile tip or the outer diameter of the sleeve is larger than that of the pile body, so that a gap exists between the outer wall of the pile body and the soil foundation after pile sinking, and the engineering difficulty is increased.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a large-diameter tubular pile with inward-inclined annular pile legs, so that pile sinking resistance can be greatly reduced, the tubular pile has a self-balancing sinking function, and a soil foundation directly grabs a pile body, so that construction difficulty is reduced, and construction efficiency is improved.

In order to solve the technical problems, the technical scheme adopted by the invention is to produce the large-diameter precast tubular pile, which comprises a pile body and a pile foot, wherein the pile body is a cylindrical pile body, and the pile foot is annular and comprises an annular end plate and an annular inclined toe. The pile body is made of reinforced concrete, and the pile foot can be directly made of pure steel materials or made of reinforced concrete; the steel reinforcement framework in the pile body is directly welded with steel of the pile foot, or directly welded with the steel reinforcement framework in the pile foot. The pile foot is made into a circular ring shape, so that the first contact position of the tubular pile and the soil body is in a circular ring shape, and the tubular pile has stability, but the first contact position of the tubular pile and the soil body is in a point shape and is not strong in stability instead of being made into a pointed end like the existing pile foot.

The annular end plate is directly generated on the upper surface of the annular inclined tiptoe, and the outer diameter of the annular end plate is the same as that of the pile body; and the welded annular end plate and the pile body are concentric circles.

The cross section of the annular inclined tiptoe is triangular, and three sides of the triangle are respectively called as an upper side, an outer side and an inner side; wherein the upper edge is the cross-section of the annular end panel; the outer edge is an edge far away from the circle center, and the outer edge inclines towards the circle center; the inner edge is an edge close to the circle center. The pile foot is actually in the shape of circular ring inward inclination, the tiptoe of the pile foot is inward inclination, so that when the pile is sunk, the soil body is gradually extruded outwards by the inward inclination circular ring tiptoe, the soil body tightly attached to the outer side of the pile foot is in a tightly attached extrusion state, the outer side soil body and the outer side of the pile foot are in a mutually attached extrusion state, the outer diameter of the annular end plate of the pile foot is the same as the outer diameter of the pile body, after the pile foot and the pile body continue to subside, the outer side of the pile body and the outer side soil body can also be in a mutually extruded state, and after the pile foot and the pile body continue to subside, the soil foundation can tightly grasp the pile. Meanwhile, as the pile foot is annular and the center of the pile foot is hollow round, when the pile is sunk, the soil body at the position of the hollow round at the center can penetrate through the hollow round, so that the resistance of the soil body at the position is directly reduced, and the pile is very easy to sink.

Preferably, the inner edge is perpendicular to the upper edge. Namely, the inner wall of the pile foot is vertical to the annular end plate and is a pile foot with a right-angle section; therefore, when the pile is sunk, the inner wall of the pile foot and the soil body are not extruded mutually and not extruded mutually.

One structure is that the inner angle formed by the inner edge and the upper edge is in an obtuse angle shape; for obtuse angle section stake foot, can increase the extrusion force degree of outside soil body to the pile body outside like this, increase the stability and the firmness of tubular pile, nevertheless can increase pile sinking resistance, can confirm as required.

One structure is that the inner angle formed by the inner edge and the upper edge is acute angle, the angle of the inner angle is larger than the angle formed by the outer edge and the upper edge; the pile foot with the acute-angle section can further reduce pile sinking resistance, but also can reduce extrusion force degree of the soil body on the outer side of the pile body, and meanwhile, the soil body on the inner side can extrude the inner wall of the pile body.

In one configuration, the outer edge is arcuate. Thus, the annular inclined tiptoes can be thickened, damage of soil bodies to the tiptoes during pile sinking is reduced, and resistance during sedimentation is increased.

The inner diameter of the annular end face plate is smaller than that of the pile body. Can increase the extrusion force degree of outside soil body to the pile body outside like this, increase the stability and the firmness of tubular pile, nevertheless can increase pile sinking resistance, can confirm as required.

The inner diameter of the annular end plate is equal to that of the pile body. Therefore, when the pile is sunk, the inner wall of the pile body and the soil body are not extruded with each other.

The inner diameter of the annular end face plate is larger than that of the pile body. Therefore, when the pile is sunk, the extrusion force of the soil body on the outer side of the pile body can be reduced, and the soil body on the inner side can be extruded on the inner wall of the pile body.

The preferred angle of the outer edge to the upper edge is 60 °.

The construction method of the large-diameter precast tubular pile comprises the following steps.

1) And positioning the coordinate of the central point of the pile sinking position of the precast tubular pile.

2) And moving the pile sinking equipment to a pile sinking position, sinking the pile foot pile body of the prefabricated pipe pile into the soil by using the pile sinking equipment, and righting at any time to prevent the pile body from deviating in the pile sinking process until the pile body is settled to a preset position.

3) And hollowing the interior of the precast tubular pile, hollowing the lower part of the bottom end of the precast tubular pile, and hollowing the lateral side of the lower part of the bottom end to form a cylindrical bottom end cavity. The stability can be greatly improved by enlarging the lower part of the bottom end of the tubular pile.

4) And sand and stone are put into the center of the bottom cavity, so that a dome-shaped bulge is formed at the bottom of the bottom cavity and is covered by the permeable diaphragm.

5) And laying a dome-shaped reinforcement cage along the dome-shaped bulge, and then pouring concrete mortar until the bottom cavity is filled. After being consolidated, the bottom of the tubular pile becomes a dome-shaped bottom part below the bottom end of the tubular pile, and the dome-shaped structure can buffer vibration force from the bottom in all directions, thereby further increasing the stability of the tubular pile.

6) The prefabricated pipe pile is settled again by using settlement equipment until all the pile feet are buried in the concrete mortar without the steel reinforcement cage, and the settlement is stopped when the annular inclined toe of the pile foot is contacted with the dome-shaped steel reinforcement cage, and the dome-shaped bottom pipe pile base is formed after the reinforced concrete is solidified; then, according to a conventional method, the interior of the pipe pile is fully paved with a reinforcement cage and filled with concrete.

In the step 3), the vertical distance dug downwards is 1-2 times of the outer diameter of the tubular pile; the horizontal width hollowed out of the side is 0.3-1 times of the outer diameter of the pipe pile.

In the step 4), the diameter of the bottom surface of the bulge is the same as that of the cavity at the bottom end, and the center height of the bulge is 0.2-0.4 times of the diameter of the bottom surface of the bulge.

In the step 5), the thickness of the dome-shaped reinforcement cage is 1/2 of the height of the center of the bulge.

The invention has the advantages that the pile foot is made into a hollow ring shape, and the outer wall is inclined inwards, so that the pile sinking resistance can be greatly reduced, the tubular pile has a self-balancing sinking function, and the lateral soil foundation can directly grasp the pile body, so that the construction difficulty is reduced, and the construction efficiency is improved; the sand is put in the center of the cavity at the bottom end to form a dome-shaped bulge, then the water-permeable membrane is covered, and then the reinforced concrete is poured to form a dome-shaped tubular pile substrate, so that the vibration of the bottom can be reduced, the bottom is more stable, and the tubular pile is firmer and firmer as a whole.

Drawings

Fig. 1 is a schematic sectional view of the whole tubular pile.

Fig. 2 is a schematic view of the overall structure of the spud foot.

Fig. 3 is a schematic structural view of a right-angle section spud foot.

Fig. 4 is a schematic view of the structure of the obtuse-angle section spud foot.

Fig. 5 is a schematic structural view of the acute-angle-section spud leg.

Fig. 6 is a schematic sectional structure view of the whole pipe pile after construction.

In the figure: 1. the pile comprises a pile body, 2 pile feet, 3 annular end panels, 4 annular inclined toe tips, 5 upper edges, 6 outer edges, 7 inner edges, 8 right-angle section pile feet, 9 obtuse-angle section pile feet, 10 acute-angle section pile feet, 11 bottom end cavities, 12 dome-shaped bulges, 13 permeable membranes, 14 dome-shaped reinforcement cages, 15 sand, 16 concrete mortar and 17 dome-shaped bottom pipe pile bases.

Detailed Description

The present invention is further illustrated by the following examples, which are intended to illustrate the invention but not to limit it further, and should not be construed as limiting the scope of the invention.

Example 1.

As shown in the figure, make a major diameter high strength precast tubular pile, this tubular pile includes pile body 1 and spud foot 2, pile body 1 is cylindric pile body, spud foot 2 is the ring form spud foot, spud foot 2 includes cyclic annular end plate 3 and cyclic annular slope tiptoe 4. The pile body 1 is made of reinforced concrete, and the pile foot 2 is directly made of pure steel materials; the steel reinforcement framework in the pile body 1 is directly welded with pure steel materials serving as the annular end plates 3 on the pile feet 2.

The annular end plate 3 is directly generated on the upper surface of the annular inclined tiptoe 4, and the outer diameter of the annular end plate 3 is the same as that of the pile body 1; the welded annular end plate 3 and the pile body 1 are concentric.

The cross section of the annular inclined tiptoe 4 is made into a triangular shape, and three sides of the triangular shape are respectively called as an upper side 5, an outer side 6 and an inner side 7; wherein the upper edge 5 is in fact the cross section of the annular end panel 3; the outer edge 6 is an edge far away from the center of the circle, and the outer edge 6 inclines from the upper edge 5 to the inner edge 7 and faces the center of the circle; the inner edge 7 is an edge close to the center of the circle. I.e. the spud 2 is in fact circular and inwardly inclined, the toe of which is inwardly inclined.

The best structure of the spud foot produced in this example is: the triangle of the cross section of the spud foot 2 is made such that the inner edge 7 is perpendicular to the upper edge 5. Namely, the inner wall of the pile foot 2 is vertical to the annular end plate 3 and is a pile foot 8 with a right-angle section; therefore, when the pile is sunk, the inner wall of the pile foot and the soil body are not extruded mutually and not extruded mutually.

The pile foot can also be made into a structure, namely, an inner angle formed by the inner edge 7 and the upper edge 5 is made into an obtuse angle shape; for obtuse angle section stake foot 9, can increase the extrusion force degree of outside soil body to the pile body outside like this, increase the stability and the firmness of tubular pile, nevertheless can increase pile sinking resistance, can confirm as required.

The pile foot can also be made into a third structure, namely an inner angle formed by the inner edge 7 and the upper edge 5 is made into an acute angle shape, and the angle of the inner angle is larger than that of an outer angle formed by the outer edge 6 and the upper edge 5; the pile foot 10 with the acute-angle section is formed, so that pile sinking resistance can be further reduced, the extrusion force of the soil body on the outer side of the pile body can be reduced, and meanwhile, the soil body on the inner side can extrude the inner wall of the pile body.

In addition, the outer sides of the pile feet 2 with the three structures, namely the triangular outer sides 6 on the cross section, can be made into arc shapes. Thus, the annular inclined tiptoes can be made thick and strong, the damage of soil bodies to the tiptoes during pile sinking is reduced, and the resistance is increased.

In the above-described pile foot 2 having various configurations, the inner diameter of the annular end plate 3 may be made smaller than the inner diameter of the pile body 1. Can increase the extrusion force degree of outside soil body to the pile body outside like this, increase the stability and the firmness of tubular pile, nevertheless can increase pile sinking resistance, can confirm as required.

The inner diameter of the annular end plate 3 may be made equal to the inner diameter of the pile body 1. Therefore, when the pile is sunk, the inner wall of the pile body and the soil body are not extruded with each other.

The inner diameter of the annular end plate 3 may be made larger than the inner diameter of the pile body 1. Therefore, when the pile is sunk, the extrusion force of the soil body on the outer side of the pile body can be reduced, and the soil body on the inner side can be extruded on the inner wall of the pile body.

Example 2.

As shown in FIG. 6, a root base is designed as PHC-AB2000 x 350 _ C₈₀The type, the major diameter prestressed precast concrete tubular pile of pile length 11m carries out pile sinking construction, and the external diameter of the annular end face board of the toe that this tubular pile was taken is 2000mm, and the internal diameter is 1100mm, and the length of the higher authority of the triangle-shaped of toe cross section of toe is 450mm, and interior limit length is 770mm, and its pile sinking construction includes following step.

2) And moving the pile sinking equipment to a pile sinking position, sinking the pile foot 2 and the pile body 1 of the precast tubular pile into the soil by using the pile sinking equipment, and righting at any time to prevent the pile body from deviating in the pile sinking process until the pile body is settled to a preset position.

3) And (3) pumping water, excavating muddy water and gravels in the precast tubular pile, excavating the lower part of the bottom end of the precast tubular pile for 2.5 meters, and additionally excavating for 1 meter towards the outside of the side to form a cylindrical bottom end cavity 11 with the diameter of 4 meters and the height of 2.5 meters.

4) Sand 15 is put into the center of the bottom cavity, so that a dome-shaped bulge 12 is formed at the bottom of the bottom cavity, the diameter of the bottom surface of the bulge is 4 m, and the center height of the bulge is 1 m; and then covered with a water-permeable nonwoven fabric as the water-permeable membrane 13.

5) The domed reinforcement cage 14 is laid along the domed bulge 12, the reinforcement cage is made 500mm thick and then concrete mortar 16 is poured until the bottom cavity is filled.

6) The prefabricated pipe pile is settled again by using settlement equipment until the pile foot 2 is completely buried in the concrete mortar 16 without laying a reinforcement cage, and the settlement is stopped when the annular inclined toe 4 of the pile foot 2 contacts the dome-shaped reinforcement cage 14, and the pipe pile base 17 with the dome-shaped bottom is formed after the reinforced concrete is solidified; then, according to a conventional method, the interior of the pipe pile is fully paved with a reinforcement cage and filled with concrete.

The method is also suitable for the staged propelling sedimentation of the multi-section tubular piles, and the sinking construction with larger depth is completed.

Claims

1. A construction method of a large-diameter precast tubular pile is characterized by comprising the following steps:

the tubular pile comprises a pile body and a pile foot; the pile foot is annular and comprises an annular end plate and an annular inclined toe;

the annular end plate is directly generated on the upper surface of the annular inclined tiptoe, and the outer diameter of the annular end plate is the same as that of the pile body; the annular end plate and the pile body are concentric circles;

the cross section of the annular inclined tiptoe is triangular, and three sides of the triangle are respectively called as an upper side, an outer side and an inner side; wherein the upper edge is the cross-section of the annular end panel; the outer edge is an edge far away from the circle center, and the outer edge inclines towards the circle center; the inner edge is an edge close to the circle center;

the construction method comprises the following steps:

1) positioning the coordinate of the center point of the pile sinking position of the precast tubular pile;

2) moving pile sinking equipment to a pile sinking position, sinking a pile foot pile body of the prefabricated pipe pile into the soil by utilizing the pile sinking equipment, and righting at any time to prevent the pile body from deviating in the pile sinking process until the pile body is settled to a preset position;

3) hollowing the interior of the precast tubular pile, hollowing the lower part of the bottom end of the precast tubular pile, and hollowing the lateral side of the lower part of the bottom end to form a cylindrical bottom end cavity;

4) sand and stone are put into the center of the bottom cavity, so that a dome-shaped bulge is formed at the bottom of the bottom cavity and is covered by a permeable diaphragm;

5) laying a dome-shaped reinforcement cage along the dome-shaped bulge, and then pouring concrete mortar until the bottom cavity is filled;

6) the prefabricated pipe pile is settled again by using settlement equipment until all the pile feet are buried in the concrete mortar without the steel reinforcement cage, and the settlement is stopped when the annular inclined toe of the pile foot is contacted with the dome-shaped steel reinforcement cage, and the dome-shaped pipe pile base is formed after the reinforced concrete is solidified; then, according to a conventional method, the interior of the pipe pile is fully paved with a reinforcement cage and filled with concrete.

2. The construction method of the large-diameter precast tubular pile according to claim 1, wherein the inner edge is perpendicular to the upper edge; namely, the inner wall of the pile foot is vertical to the annular end plate and is a pile foot with a right-angle section.

3. The construction method of the large-diameter precast tubular pile according to claim 1, wherein an inner angle formed by the inner edge and the upper edge is obtuse; is an obtuse-angle section pile foot.

4. The construction method of the large-diameter precast tubular pile according to claim 1, wherein the inner angle formed by the inner edge and the upper edge is acute, and the angle of the inner angle is greater than the angle of the outer angle formed by the outer edge and the upper edge and is an acute-section leg.

5. The construction method of the large-diameter precast tubular pile according to any one of claims 2 to 4, wherein the outer edge is in an arc shape.

6. The construction method of the large-diameter precast tubular pile according to claim 5, wherein the inner diameter of the annular end plate is smaller than that of the pile body.

7. The construction method of the large-diameter precast tubular pile according to claim 5, wherein the inner diameter of the annular end plate is equal to the inner diameter of the pile body.

8. The construction method of the large-diameter precast tubular pile according to claim 5, wherein the inner diameter of the annular end plate is larger than that of the pile body.

9. The construction method of the large-diameter precast tubular pile according to claim 8, characterized in that in the step 3), the vertical distance dug downwards is 1-2 times of the outer diameter of the tubular pile; the horizontal width hollowed out of the side is 0.3-1 times of the outer diameter of the tubular pile;

in the step 4), the diameter of the bottom surface of the bulge is the same as that of the cavity at the bottom end, and the center height of the bulge is 0.2-0.4 times of the diameter of the bottom surface of the bulge;