Precast concrete pile structure capable of reducing negative friction

Abstract

The prefabricated concrete pile structure capable of reducing the negative friction resistance comprises a concrete pile body and a negative friction resistance eliminating device, the concrete pile body is composed of an upper pile body and a lower pile body, and the lower portion of the upper pile body and the top of the lower pile body are connected into a whole through a connecting structure; the negative friction eliminating device is arranged on the outer side of the bottom of the upper pile body and comprises an inner sleeve and an outer sleeve, and the upper pile body is sleeved with the inner sleeve. A circle of protruding anti-sliding keys are arranged on the outer surface of the bottom of the inner sleeve, the outer side of the lower portion of the inner sleeve is sleeved with an outer sleeve, the outer sleeve is fixedly connected with the upper pile body, and an energy-absorbing rubber material layer is installed on the inner wall of the outer sleeve. The protruding height of the anti-sliding key enables the distance between the top of the anti-sliding key and the center line of the inner sleeve to be larger than the radius of the inner side of the energy-absorbing rubber material layer, and the anti-sliding key can extrude the energy-absorbing rubber material layer. The utility model has the advantages of simple structure and convenience in manufacture and construction.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of prefabricated concrete pile structures that can reduce negative friction, especially applicable to pile foundation engineering under soft soil foundation condition. BACKGROUND

[0002] When using pile foundation in soft soil layer area such as loose new fill, underconsolidated soil, self-weight collapsible loess, etc., due to compression consolidation of soil under self-weight, collapse or settlement under ground additional load, when the deformation of soil around pile is greater than pile foundation itself, at this time, soil around pile will generate downward negative friction to pile, the existence of negative friction will not only reduce the vertical bearing capacity of pile, but also according to specification requirements, when carrying out pile foundation bearing capacity checking, negative friction should also be added as external load on pile, thereby leading to the increase of engineering cost.

[0003] At present, the method for eliminating negative friction of pile foundation mainly includes two categories: one is to make soft soil layer complete most of settlement deformation before pile foundation construction through foundation treatment method, but this method generally has long construction period and high cost; the second is to isolate pile body from soft soil layer through physical method, including smearing lubricating coating such as asphalt on pile body, or setting isolation protective sleeve outside pile body, etc., but there are still many problems, for example, there are many factors affecting the efficacy of coating such as asphalt, at the same time, coating such as asphalt is easily damaged in pile foundation driving construction process, and construction quality and effect are difficult to guarantee. While the existing method for setting protective sleeve outside pile foundation has too complex structure, is difficult to manufacture, and protective sleeve and pile foundation need to be constructed separately, which increases construction difficulty and engineering cost, and is difficult to be popularized and applied on a large scale. UTILITY MODEL CONTENT

[0004] The utility model aims at the problems existing in prior art, and provides a kind of prefabricated concrete pile structure that can reduce negative friction, which has the advantages of simple structure, easy manufacturing and construction. The utility model adopts the technical scheme of:

[0005] A kind of prefabricated concrete pile structure that can reduce negative friction, characterized by including concrete pile main body and negative friction elimination device, the concrete pile main body is composed of upper pile body and lower pile body, the diameter of lower pile body is greater than the diameter of upper pile body, the lower part of upper pile body and the top of lower pile body are connected as a whole by connecting structure;

[0006] The negative friction elimination device is arranged outside the bottom of upper pile body, and the negative friction elimination device includes inner sleeve and outer sleeve, and the inner sleeve is sleeved on the outer of upper pile body;

[0007] The inner sleeve is a hollow steel pipe structure, the inner ring diameter of the inner sleeve is slightly larger than the diameter of the upper pile body, and a circle of protruding anti-skid keys is arranged on the outer surface of the bottom of the inner sleeve, the outer sleeve is arranged on the outer side of the lower part of the inner sleeve, the outer sleeve is a hollow steel pipe structure, the outer sleeve is fixedly connected with the upper pile body, and the inner ring diameter of the outer sleeve is greater than the outer ring diameter of the inner sleeve plus the protruding height of the anti-skid keys;

[0008] The inner wall of the outer sleeve is provided with an energy-absorbing rubber material layer, the protruding height of the anti-skid keys is greater than the inner side radius of the energy-absorbing rubber material layer, and the anti-skid keys can extrude the energy-absorbing rubber material layer.

[0009] On the basis of the above technical scheme, the utility model further uses the following further technical schemes, or uses the further technical schemes in combination.

[0010] The connecting structure adopts a flange structure, the upper pile body and the lower pile body are connected as a whole through the flange structure, and the two flange structures are connected and fixed through nuts and screw rods.

[0011] The flange structure adopts a double-layer flange disc structure, the first layer flange disc is used for being connected with the lower part of the upper pile body or the top of the lower pile body, the second layer flange disc is used for being connected and fixed between the two flange structures through nuts and screw rods, and the first layer flange disc and the second layer flange disc are connected through a plurality of fixing rods.

[0012] The anti-skid key is a hemispherical protruding structure, and the anti-skid key and the outer surface of the inner sleeve are connected through welding.

[0013] The outer sleeve is welded with the flange structure at the bottom of the upper pile body.

[0014] The outer diameter of the outer sleeve is the same as the diameter of the lower pile body.

[0015] A sealing rubber ring is arranged between the top of the outer sleeve and the outer surface of the inner sleeve.

[0016] The gap between the inner sleeve and the upper pile body is filled with lubricating material.

[0017] The pile body is arranged in the bearing soil layer below the neutral point, and the upper pile body is arranged in the soft soil layer above the neutral point.

[0018] When the soil around the pile settles due to consolidation, subsidence or under additional load, the soil exerts a downward negative friction force on the inner sleeve, at which time the inner sleeve will move downward relative to the pile body and extrude the energy-absorbing rubber material on the inner side of the outer sleeve through the anti-skid key, and since the energy-absorbing material has good deformation capacity, only a small frictional resistance is generated on the inner sleeve, and the resistance is constant, thereby realizing the effect of eliminating the negative frictional resistance through the downward deformation of the inner sleeve.

[0019] The utility model discloses the beneficial effects are:

[0020] The device has simple structure, and the concrete pile body, the inner sleeve and the outer sleeve can be prefabricated in a factory, then assembled on site, so that the device is convenient to manufacture and transport, and the length of the upper pile body and the lower pile body can be flexibly adjusted according to the design scheme.

[0021] The pile body is isolated from the soft soil layer by the inner sleeve and the outer sleeve, and when the soil layer exerts a downward negative frictional resistance on the pile body, the negative frictional resistance can be well eliminated through the downward deformation of the inner sleeve, so that the influence of the negative frictional resistance on the bearing capacity of the pile foundation is reduced.

[0022] The negative frictional resistance eliminating device is welded with the concrete pile as a whole, so that the pile foundation can be punched in one time, multiple construction operations are avoided, construction is convenient, and better economic benefits are achieved. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The utility model discloses a structure schematic diagram of an embodiment. Wherein, only a part of the upper pile body and the lower pile body is schematically shown.

[0024] Figure 2 The utility model discloses a structure schematic diagram of an embodiment. Figure 1 The utility model discloses a structure schematic diagram of an embodiment.

[0025] Figure 3 The utility model discloses a structure schematic diagram of an embodiment. Figure 1 The utility model discloses a structure schematic diagram of an embodiment.

[0026] Figure 4 The utility model discloses a structure schematic diagram of an embodiment. Figure 1 The utility model discloses a structure schematic diagram of an embodiment. DETAILED DESCRIPTION

[0027] With reference to the drawings. The embodiment is a prefabricated concrete pile structure capable of reducing negative frictional resistance, mainly used in pile foundation engineering with soft soil layer in shallow layer, and capable of effectively reducing the influence of negative frictional resistance on the pile foundation.

[0028] The precast concrete pile structure includes a concrete pile body and a negative skin friction elimination device. The concrete pile body consists of an upper pile body 1 and a lower pile body 2. The diameter of the lower pile body 2 is larger than the diameter of the upper pile body 1. The lower pile body 2 is arranged in the bearing soil layer below the neutral point, and the upper pile body 1 is arranged in the soft soil layer above the neutral point. The neutral point refers to the cross-sectional position where there is no relative displacement between the pile and the soil.

[0029] Both the lower part of the upper pile body 1 and the top of the lower pile body 2 are pre-installed with flange structures 3, which connect the upper pile body 1 and the lower pile body 2 into a whole. The two flange structures 3 are connected and fixed together by nuts 4 and bolts 5. The flange structure adopts a double-layer flange structure. The first layer flange 31 is used to connect to the lower part of the upper pile body 1 or the top of the lower pile body 2, and the second layer flange 32 is used to connect and fix the two flange structures 3 together by nuts 4 and bolts 5. The first layer flange 31 and the second layer flange 32 are connected by multiple fixing rods 33.

[0030] The negative skin friction elimination device is arranged on the outer side of the bottom of the upper pile body 1. The negative skin friction elimination device includes an inner sleeve 6 and an outer sleeve 7 that are slidably connected; the inner sleeve 6 is fitted over the upper pile body 1.

[0031] The inner sleeve 6 is a hollow steel pipe structure. The inner ring diameter of the inner sleeve 6 is slightly larger than the diameter of the upper pile body 1. A ring of raised anti-slip keys 8 is provided on the outer surface of the bottom of the inner sleeve 6. The anti-slip keys 8 are hemispherical raised structures. The anti-slip keys 8 are connected to the outer surface of the inner sleeve 6 by welding.

[0032] The lower outer side of the inner sleeve 6 is fitted with an outer sleeve 7, which is also a hollow steel pipe structure. The outer sleeve 7 is welded to the flange 31 at the bottom of the upper pile body. The inner ring diameter of the outer sleeve 7 is larger than the outer ring diameter of the inner sleeve 6 plus the protrusion height of the anti-slip key. The outer diameter of the outer sleeve 7 is the same as the diameter of the lower pile body 2.

[0033] An energy-absorbing rubber material layer 9 of a certain thickness is installed on the inner wall of the outer sleeve 7. The energy-absorbing rubber material layer 9 has good hardness and plasticity, and can undergo recoverable elastic deformation under a certain external force.

[0034] like Figure 3 As shown, the protrusion height of the anti-slip key 8 is such that the distance between its top and the center line of the inner sleeve 6 is greater than the inner radius of the energy-absorbing rubber material layer 9, which satisfies the requirement that it can compress the energy-absorbing rubber material layer 9. Through the interaction between the anti-slip key 8 and the energy-absorbing rubber material layer 9, firstly, the stability of the inner sleeve 6 under its own weight can be ensured, and secondly, the energy-absorbing rubber material layer 9 will deform under the action of downward negative friction resistance, thereby allowing the inner sleeve 6 to move downward and eliminate negative friction resistance.

[0035] Further, the cross-sectional size of the anti-skid key 8 can be adjusted as needed, or multiple sets of anti-skid keys can be provided, so as to change the size of the external force that causes the inner sleeve 6 to be displaced downward.

[0036] Further, a sealing rubber ring 10 is provided between the top of the outer sleeve 7 and the outer surface of the inner sleeve 6.

[0037] Further, the gap between the inner sleeve 6 and the upper pile body 1 is filled with soft pitch or other lubricating material.

[0038] The prefabricated concrete pile structure manufacturing and construction of the embodiment includes the following steps:

[0039] (1) In an indoor environment such as a factory, the upper pile body, the lower pile body, the inner sleeve, the outer sleeve, and other structures are manufactured according to the design scheme. The concrete pile body needs to be cured until it reaches the required strength according to the design requirements. The anti-skid key 8 at the bottom of the inner sleeve is welded in the indoor environment (welded on the outer side of the inner sleeve), and the energy-absorbing rubber material layer 9 is bonded to the inner side of the outer sleeve.

[0040] (2) The prefabricated pile foundation components are transported to the construction site, and the outer sleeve is fixed to the flange plate at the bottom of the upper pile body according to the design scheme. The welding connection is performed on site.

[0041] (3) The inner sleeve is placed inside the outer sleeve, and the sealing rubber ring is installed between the top of the outer sleeve and the outer surface of the inner sleeve.

[0042] (4) The upper pile body and the lower pile body are connected as a whole through the flange plate, and the structure assembly is completed.

[0043] (5) According to the design, the pile foundation is driven into the designated position at one time, and then the soft pitch or other lubricating material is filled in the gap between the inner sleeve and the upper pile body, and the pile foundation construction is completed.

[0044] The above description is only to illustrate the specific implementation cases of the present application, and is not intended to limit the scope of the present application. All equivalent changes or modifications made by skilled persons in the art without departing from the spirit and principles of the present application should still be covered by the scope of the claims of the present application.

Claims

1. A precast concrete pile structure that reduces negative skin friction, characterized in that The concrete pile body is composed of an upper pile body and a lower pile body, the diameter of the lower pile body is larger than that of the upper pile body, and the lower part of the upper pile body and the top of the lower pile body are connected into an integral whole through a connecting structure. The negative friction resistance eliminating device is arranged outside the bottom of the upper pile body, and the negative friction resistance eliminating device comprises an inner sleeve and an outer sleeve, the inner sleeve is sleeved outside the upper pile body; The inner sleeve is a hollow steel pipe structure, the inner ring diameter of the inner sleeve is slightly larger than the diameter of the upper pile body, the outer surface of the bottom of the inner sleeve is provided with a row of protruding anti-skid keys, the lower outer side of the inner sleeve is sleeved with the outer sleeve, the outer sleeve is a hollow steel pipe structure, the outer sleeve is fixedly connected with the upper pile body, and the inner ring diameter of the outer sleeve is larger than the outer ring diameter of the inner sleeve plus the protruding height of the anti-skid keys; The inner wall of the outer sleeve is provided with an energy-absorbing rubber material layer, the protruding height of the anti-skid keys is greater than the inner side radius of the energy-absorbing rubber material layer, so that the anti-skid keys can extrude the energy-absorbing rubber material layer.

2. A precast concrete pile structure of the type defined in claim 1, wherein The connecting structure adopts a flange structure, the lower part of the upper pile body and the top of the lower pile body are pre-installed with flange structures, and the upper pile body and the lower pile body are connected into an integral whole through the flange structures, and the two flange structures are connected and fixed through nuts and screws.

3. A precast concrete pile construction of claim 2, wherein The flange structure adopts a double-layer flange disc structure, the first layer flange disc is used for connecting the lower part of the upper pile body or the top of the lower pile body, the second layer flange disc is used for connecting and fixing the two flange structures through nuts and screws, and the first layer flange disc and the second layer flange disc are connected through a plurality of fixing rods.

4. A precast concrete pile structure of claim 1, wherein The anti-skid keys are semispherical convex structures, and the anti-skid keys and the outer surface of the inner sleeve are connected through welding.

5. A precast concrete pile structure of the type defined in claim 2, wherein The outer sleeve and the flange structure of the bottom of the upper pile body are welded.

6. A precast concrete pile structure of the type defined in claim 1, wherein The outer diameter of the outer sleeve is the same as the diameter of the lower pile body.

7. A precast concrete pile structure of claim 1, wherein A sealing rubber ring is arranged between the top of the outer sleeve and the outer surface of the inner sleeve.

8. A precast concrete pile structure of claim 1, wherein The gap between the inner sleeve and the upper pile body is filled with lubricating material.

9. A precast concrete pile construction of reduced negative skin friction as claimed in claim 1, 2, 3, 4, 5, 6, 7 or 8 wherein The lower pile body is arranged in the bearing soil layer below the neutral point, and the upper pile body is arranged in the soft soil layer above the neutral point.

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