CN219604331U - Vertical composite pile of flexible pile and rigid pile - Google Patents

Abstract

The utility model discloses a vertical combined pile of a flexible pile and a rigid pile, which comprises a flexible pile section, a connecting pile section and a rigid pile section which are sunk into foundation soil, wherein the flexible pile section, the connecting pile section and the rigid pile section are vertically arranged, the flexible pile section, the connecting pile section and the rigid pile section are sequentially spliced from bottom to top to form the combined pile, the pile end of the flexible pile section is positioned on a soil layer with better compressibility, and the end of the rigid pile section is used for being connected with the foundation. The combined pile can fully utilize the flexible pile section to treat the foundation in a soft soil area, can also meet the seepage-proofing requirement of a hydraulic building constructed on the soft foundation, and can treat a liquefied soil layer with any depth.

Description

Vertical composite pile of flexible pile and rigid pile

Technical Field

The utility model belongs to the technical field of hydraulic engineering foundation treatment, and particularly relates to a vertical combined pile of a flexible pile and a rigid pile.

Background

The common flexible piles comprise sand stone piles, CFG piles and vibroflotation piles, the materials of which constitute the pile body are discrete materials, and the flexible pile composite foundation has remarkable economical efficiency and good reinforcement, so that the flexible pile composite foundation is widely applied to the foundation treatment in soft soil areas. The flexible piles have the functions of compacting soil among piles, eliminating liquefaction and water permeability, the soil among piles represents the soil among adjacent pile bodies, and the improvement of the bearing capacity of the composite foundation mainly depends on the compaction effect of the soil among piles, so that the adoption of the flexible piles is focused on the compaction effect by utilizing the soil among piles. For liquefiable foundations, the flexible piles are the preferred piles, the pile bodies of the flexible piles are good drainage channels, pore water can be discharged along the pile bodies under the action of an earthquake, and in addition, the compaction effect on soil bodies during pile formation of the flexible piles is beneficial to eliminating liquefaction and improving the bearing capacity of the foundations.

Most of hydraulic buildings need water retaining, have the requirements of seepage prevention, liquefaction resistance, settlement reduction, bearing capacity improvement and the like, but after the foundation treatment is carried out by adopting single flexible piles such as sand stone piles, CFG piles, vibroflotation piles and the like, the standard requirements are difficult to meet, so that the flexible piles are less applied to the hydraulic buildings, and the main reasons are as follows:

(1) The top of the flexible pile is susceptible to bulge damage: fig. 1 is a schematic diagram of a stress state of a pile top of a single flexible pile, in fig. 1, P1 represents a limit load to which a pile top of the flexible pile 9 is subjected, P2 represents pile end resistance, the surrounding soil at the top of the flexible pile 9 cannot provide enough confining pressure under the effect of the limit load, and excessive lateral deformation of a pile body of the flexible pile 9 is difficult to prevent, so that the pile body at the top of the flexible pile 9 is easy to bulge and damage and forms a bulge damage area 8, wherein the bulge damage is basically distributed in a height 1-3 times of a pile diameter of the pile top of the flexible pile 9, the pile body below the bulge area is difficult to transfer load, and when the pile end falls into a soil layer with lower compressibility, the bulge damage occurs under the effect of the limit load without exerting the pile end resistance.

(2) The flexible pile top is generally required to be provided with a mattress layer, and can not meet the seepage-proofing requirement of a hydraulic building. In order to effectively transfer load, a particulate cushion layer with a certain thickness, namely a mattress cushion layer, is required to be arranged between each flexible pile and a foundation, the mattress cushion layer can relatively and uniformly distribute the load transferred by the foundation to the top surface of soil between each flexible pile and the pile, the effect of adjusting the load sharing ratio of soil between piles is achieved, the exertion of the bearing capacity of the soil foundation between piles is facilitated, but if the particulate cushion layer with better water permeability, namely the mattress cushion layer, is adopted, the seepage prevention requirement of a hydraulic building cannot be obviously met, but if the mattress cushion layer is not arranged, the stress of the flexible pile composite foundation can be influenced, in addition, the pile body of the flexible pile cannot meet the seepage prevention requirement, the pile top of the flexible pile and the foundation cannot be connected, and the seepage prevention arrangement of the hydraulic building is influenced.

(3) The flexible pile has the phenomenon of effective pile length: under the action of pile top load of the flexible pile, pile body stress of the flexible pile is downwards transferred, and due to the action of friction resistance of the side of the flexible pile, the pile body stress of the flexible pile is gradually reduced, and the stress is zero at a certain depth of the pile body of the flexible pile, so that even if the pile end of the flexible pile falls on a soil layer with lower compressibility, the pile end resistance action is very small, and is generally ignored, therefore, when the foundation treatment takes the bearing capacity improvement as a control condition, the meaning of lengthening the flexible pile is not great, but when the liquefaction layer is deeper, the effective pile length of the flexible pile is difficult to treat the liquefaction soil layer, namely, after the effective pile length is met, the requirement of liquefaction elimination is difficult to meet.

How to solve the defects existing in the prior art so as to meet the foundation treatment requirement of hydraulic engineering, and technical innovation is needed urgently.

Disclosure of Invention

In view of the defects of the prior art, the utility model provides the vertical combined pile of the flexible pile and the rigid pile, which not only can fully utilize the flexible pile section to treat the foundation in a soft soil area, but also can meet the seepage-proofing requirement of a hydraulic building built on the foundation, can treat the liquefied soil layer with any depth, and can meet the effective length of the flexible pile section.

The technical scheme adopted for solving the technical problems is as follows:

the utility model provides a vertical composite pile of flexible stake and rigid pile, includes the flexible stake section of sinking in foundation soil, meets stake section and rigid pile section, flexible stake section, meet stake section and the equal vertical arrangement of rigid pile section, flexible stake section, meet stake section and rigid pile section splice in proper order from the bottom up and form the composite pile, flexible stake section pile end is in on the better soil layer of compressibility, rigid pile section end is used for being connected with the basis.

Further, the flexible pile section is one of a sand stone pile, a CFG pile and a vibroflotation pile; the rigid pile segments are concrete piles or reinforced concrete piles; the connected pile segments are semi-flexible piles.

Further, the length of the flexible pile section is determined according to the treatment depth of foundation soil liquefaction, and the length of the flexible pile section is the difference between the foundation treatment depth of the combined pile and the length of the rigid pile section and the length of the connected pile section.

Further, the length of the contiguous pile segment is determined according to the anchoring length of the rigid pile segment, the length of the contiguous pile segment is greater than or equal to 1.3 times the diameter of the flexible pile segment, and the diameter of the contiguous pile segment is equal to the diameter of the flexible pile segment.

Further, the length of the rigid pile section is 1 time or more the diameter of the flexible pile section, and the diameter of the rigid pile section is less than or equal to the diameter of the flexible pile section.

Compared with the prior art, the utility model has the beneficial effects that:

the utility model relates to a vertical combined pile of a flexible pile and a rigid pile, which comprises a flexible pile section, a connecting pile section and a rigid pile section which are immersed in foundation soil, wherein the flexible pile section, the connecting pile section and the rigid pile section are vertically arranged, the flexible pile section, the connecting pile section and the rigid pile section are spliced in sequence from bottom to top to form a combined pile, the pile end of the flexible pile section is positioned on a soil layer with better compressibility, and the end of the rigid pile section is used for being connected with a foundation; the length of the rigid pile section in the combined pile can be adjusted according to the requirement, so that the flexible pile section can be fully utilized to treat the foundation in a soft soil area, the economic efficiency and the good reinforcement are obvious, and the combined pile can meet the anti-seepage requirement of a hydraulic building constructed on the foundation due to the effect of the rigid pile section, and can treat a liquefied soil layer with any depth.

In conclusion, the combined pile combines the advantages of the flexible pile and the rigid pile, so that pile bodies made of different materials and soil around the pile cooperatively exert the integral bearing effect, the conditions that the flexible pile is easy to cause foundation penetration, the pile top of the flexible pile is easy to bulge and damage and the like can be avoided, the economical efficiency of the flexible pile can be effectively utilized, the bearing capacity of the combined pile can be improved by 30% -50% compared with that of a conventional single flexible pile, the combined pile is low in construction cost and short in construction period, the anti-seepage safety of a hydraulic building constructed on a soft foundation can be improved, and the combined pile has wide popularization and use space in hydraulic engineering.

Drawings

FIG. 1 is a schematic view of a stress state of a pile top of a single flexible pile according to the background art;

FIG. 2 is a schematic view of a vertical combined pile of flexible piles and rigid piles according to the present utility model;

fig. 3 is a schematic top cross-sectional view of the contiguous pile segment of fig. 2.

The reference numerals in the drawings illustrate: 1. flexible pile segment, 2, connected pile segment, 3, rigid pile segment, 4, soil layer with better compressibility, 5, foundation, 6, concrete, 7, broken stone, 8, bulge damage area, 9, flexible pile.

Description of the embodiments

The following describes the embodiments of the present utility model in further detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present utility model and are not intended to be limiting.

In the description of the present utility model, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

As shown in fig. 2, the vertical combined pile of the flexible pile and the rigid pile comprises a flexible pile section 1 sunk into foundation soil, a connecting pile section 2 and a rigid pile section 3, wherein the flexible pile section 1, the connecting pile section 2 and the rigid pile section 3 are vertically arranged, the flexible pile section 1, the connecting pile section 2 and the rigid pile section 3 are sequentially spliced from bottom to top to form the combined pile, the pile end of the flexible pile section 1 is positioned on a soil layer 4 with better compressibility, so that the flexible pile section 1 exerts the maximum economical efficiency, and the end head of the rigid pile section 3 is used for being connected with a foundation 5.

Because the traditional flexible pile has two defects, firstly, the pile top has the condition of bulge and damage, and secondly, the upper part of the pile top and the mattress layer cannot meet the seepage-proofing requirement of a hydraulic building. The combined pile is formed by sequentially splicing the flexible pile segments 1, the connected pile segments 2 and the rigid pile segments 3 which are vertically arranged from bottom to top, so that the combined pile adopts a vertical combined mode, the flexible pile segments 1 have a certain burial depth, the surrounding soil of the pile can provide enough confining pressure, the pile body of the flexible pile segments 1 can be prevented from being excessively deformed laterally, the situation of bulge and damage of the pile top of the common flexible pile can be avoided, the length of the rigid pile segments 3 in the combined pile can be adjusted according to the needs, the foundation can be fully treated by using the flexible pile segments 1 in soft soil areas, the obvious economical efficiency and good reinforcement are realized, and due to the effect of the rigid pile segments 3, the combined pile can meet the seepage-proofing requirement of a hydraulic building constructed on the foundation, and the liquefied soil layer with any depth can be treated.

In one embodiment, the flexible pile segment 1 is one of a gravel pile, a CFG pile and a vibroflotation pile; the rigid pile section 3 is a concrete pile or a reinforced concrete pile, and when the upper load is larger and the surrounding soil of the pile under the foundation 5 is weaker, the reinforced concrete pile can be adopted to improve the transverse tensile strength of the rigid pile section 3; the spliced pile segments 2 are semi-flexible piles, the spliced pile segments 2 are formed by the penetration of concrete 6 into the interstices of crushed rock material 7, and the crushed rock material in the spliced pile segments 2 is the same as the crushed rock material forming the flexible pile segments 1, see fig. 3.

In one embodiment, the length of the flexible pile section 1 is determined according to the treatment depth of the foundation soil liquefaction, and the length of the flexible pile section 1 is the difference between the foundation treatment depth of the composite pile and the length of the rigid pile section 3 and the length of the adjoining pile section 2.

In one embodiment, the contiguous pile segment 2 serves as a foundation 5 of the upper rigid pile segment 3, the length of the contiguous pile segment 2 is determined according to the anchoring length of the rigid pile segment 3, the length of the contiguous pile segment 2 is greater than or equal to 1.3 times the diameter of the flexible pile segment 1, and the diameter of the contiguous pile segment 2 is equal to the diameter of the flexible pile segment 1.

In one embodiment, the length of the rigid pile section 3 is 1 times or more the diameter of the flexible pile section 1, and the diameter of the rigid pile section 3 is equal to or less than the diameter of the flexible pile section 1, wherein the length of the flexible pile section 1 is typically between 6-8 m; since the bulge damage of the flexible pile is basically distributed in the height range of 1-3 times of the pile diameter of the pile top, the bulge damage of the flexible pile top can be eliminated by setting the length of the rigid pile section 3 to be 1 time or more of the diameter of the flexible pile section 1.

The construction method of the vertical combined pile of the flexible pile and the rigid pile comprises the following steps:

s1, determining a pile position through measuring paying-off, and placing construction machinery in place;

s2, construction of the flexible pile section 1: selecting one of a sand pile, a CFG pile and a vibroflotation pile according to design requirements, wherein a pile forming machine is used for mechanically constructing a immersed tube according to a construction mode of a conventional flexible pile, namely, a vibrator is started, the immersed tube is immersed into foundation soil to reach a design depth, vibration is kept, a certain amount of broken stone is poured into a hollow cavity of the immersed tube, then the vibrator is started, the tube is pulled up, a certain amount of broken stone is poured into the hollow cavity of the immersed tube, the tube is pulled up while vibrating, and feeding, vibrating and tube pulling are repeated in sequence until the immersed tube is pulled up to the design height of the flexible pile section 1;

s3, construction of the connected pile segment 2: after the immersed tube is pulled to the top end of the flexible pile segment 1, continuously injecting crushed stone and a certain amount of concrete, repeating feeding, vibrating and tube pulling until the immersed tube is pulled to the designed height of the top end of the connected pile segment 2, and vibrating and compacting after feeding;

s4, construction of the rigid pile section 3: starting the vibrator again to fully pull out the immersed tube, at the moment, injecting concrete into the immersed tube to the bottom of the foundation 5 to form a concrete pile, wherein if the rigid pile section 3 is a reinforced concrete pile, firstly placing a reinforcement cage into the immersed tube, wherein the longitudinal reinforcement of the reinforcement cage is inserted into the adjoining pile section 2, the insertion length is not less than the anchoring length, and then injecting concrete into the bottom of the foundation 5 to form the reinforced concrete pile;

s5, repeating the steps S1-S4 according to the designed pile position arrangement, and sequentially completing the construction of other combined piles.

The combined pile combines the advantages of the flexible pile and the rigid pile, not only can avoid the conditions that the flexible pile is easy to cause foundation penetration, the pile top of the flexible pile is easy to bulge and damage, and the like, but also can ensure the economical efficiency of adopting the flexible pile, compared with the conventional single flexible pile, the combined pile has the advantages that the bearing capacity can be improved by 30% -50%, the engineering cost of the combined pile is low, the construction period is short, the anti-seepage safety of a hydraulic building constructed on a soft foundation can be improved, and the combined pile has wide popularization and use space in hydraulic engineering.

The foregoing is merely a preferred embodiment of the present utility model, and it should be noted that modifications and substitutions can be made by those skilled in the art without departing from the technical principles of the present utility model, and these modifications and substitutions should also be considered as being within the scope of the present utility model.

Claims (5)

1. A vertical composite pile of flexible pile and rigid pile, its characterized in that: including flexible stake section (1), meeting stake section (2) and rigid pile section (3) in the foundation soil sunk, flexible stake section (1), meet stake section (2) and rigid pile section (3) all vertical arrangement, flexible stake section (1), meet stake section (2) and rigid pile section (3) splice in proper order from the bottom up and form the composite pile, flexible stake section (1) pile end is in on soil layer (4) that compressibility is better, rigid pile section (3) end is used for being connected with basis (5).

2. A vertical composite pile of flexible piles and rigid piles according to claim 1, wherein: the flexible pile section (1) is one of a sand stone pile, a CFG pile and a vibroflotation pile; the rigid pile section (3) is a concrete pile or a reinforced concrete pile; the connected pile segments (2) are semi-flexible piles.

3. A vertical composite pile of flexible piles and rigid piles according to claim 2, wherein: the length of the flexible pile section (1) is determined according to the treatment depth of foundation soil liquefaction, and the length of the flexible pile section (1) is the difference between the foundation treatment depth of the combined pile and the length of the rigid pile section (3) and the length of the connected pile section (2).

4. A vertical composite pile of flexible piles and rigid piles according to claim 2, wherein: the length of the connected pile section (2) is determined according to the anchoring length of the rigid pile section (3), the length of the connected pile section (2) is greater than or equal to 1.3 times the diameter of the flexible pile section (1), and the diameter of the connected pile section (2) is equal to the diameter of the flexible pile section (1).

5. A vertical composite pile of flexible piles and rigid piles according to claim 2, wherein: the length of the rigid pile section (3) is greater than or equal to 1 time the diameter of the flexible pile section (1), and the diameter of the rigid pile section (3) is smaller than or equal to the diameter of the flexible pile section (1).