Variable stiffness anti-floating piles

Abstract

The present invention is a variable stiffness anti-floating pile, comprising a lower pile body and a connector structure, wherein a connector cavity is provided in the connector structure; an elastic pad structure is provided between the connector structure and the lower pile body, wherein an anchor bolt extending in the direction of the connector structure is connected to the lower pile body, wherein the elastic pad structure and the connector structure can be slidably mounted on the anchor bolt; the lower pile body is used to be fixed in the foundation, and the connector structure is used to connect the foundation base plate and the lower pile body. The present invention can connect the foundation base plate and the lower pile body with variable stiffness through the elastic pad structure and the connector structure. Under vertical pressure, the stiffness is zero within the settlement range, so that the settlement of the entire foundation is considered as a natural foundation, thereby avoiding uneven settlement of the foundation, avoiding foundation cracking, and ensuring foundation safety.

Description

Technical Field

[0001] The invention relates to the technical field of building anti-floating piles, in particular to a variable-rigidity anti-floating pile. Background Art

[0002] When the gravity of a building with a basement is less than its buoyancy, anti-floating measures need to be taken. The first approach is to increase the building's weight, while the second is to use anti-floating piles. If increasing the weight is uneconomical, anti-floating piles are necessary. One type of anti-floating pile is a bored cast-in-place pile. This is achieved by mechanically drilling a hole in the foundation soil at the construction site, placing a steel cage inside, and then pouring concrete. The length, diameter, and reinforcement of the pile are determined based on the pullout resistance it can withstand and the mechanical properties of the soil surrounding the pile.

[0003] Reinforced concrete bored piles can be used as anti-floating piles. These piles are formed by mechanically drilling the hole, inserting a slurry wall, placing a steel cage, and then pouring concrete. When the groundwater level is below the foundation slab, the piles are in a compressive state, exhibiting compressive vertical stiffness. When the groundwater level is at the anti-floating level, the piles are in a tensile state, exhibiting tensile vertical stiffness.

[0004] For buildings with basements, when gravity anti-floating is used on a large scale in the basement and anti-floating piles are used in some parts, when the groundwater is lower than the bottom surface of the foundation, part of the foundation is located on the natural foundation and part is located on the anti-floating piles, resulting in uneven stiffness under the foundation and uneven settlement.

[0005] Therefore, the inventors, relying on their many years of experience and practice in related industries, have proposed a variable stiffness anti-floating pile to overcome the defects of the prior art. Summary of the Invention

[0006] The purpose of the present invention is to provide a variable stiffness anti-floating pile, which can connect the foundation base plate and the lower pile body with variable stiffness through an elastic pad structure and a connector structure. Under vertical pressure, the stiffness is zero within the settlement range, so that the settlement of the entire foundation is considered as a natural foundation, avoiding uneven settlement of the foundation, avoiding foundation cracking, and ensuring foundation safety.

[0007] The object of the present invention is achieved in this way: a variable stiffness anti-floating pile includes a lower pile body and a connector structure, a connector cavity is provided in the connector structure; an elastic pad structure is provided between the connector structure and the lower pile body, an anchor bolt extending in the direction of the connector structure is connected to the lower pile body, and the elastic pad structure and the connector structure can be slidably mounted on the anchor bolt; the lower pile body is used to be fixed in the foundation, and the connector structure is used to connect the foundation base plate and the lower pile body.

[0008] In a preferred embodiment of the present invention, the connector structure includes a connector base plate, a connector riser extending upward is connected to the connector base plate, a connector cover is arranged in the connector riser, a connecting column is connected between the connector cover and the connector base plate, and the connector base plate, the connector riser and the connector cover form the connector cavity.

[0009] In a preferred embodiment of the present invention, a plurality of stiffening plates are further provided between the connector cover plate and the connector bottom plate, and the plurality of stiffening plates are spaced apart along the circumference of the connector riser.

[0010] In a preferred embodiment of the present invention, a plurality of anchor bars extending upward and obliquely are connected to the top of the connector riser.

[0011] In a preferred embodiment of the present invention, a first connecting through hole is provided in the bottom plate of the connector, a second connecting through hole is provided on the elastic pad structure, the first end of the anchor bolt passes through the second connecting through hole and the first connecting through hole and then is connected to a fixing nut, and the second end of the anchor bolt is embedded in the lower pile body.

[0012] In a preferred embodiment of the present invention, the elastic pad structure is a soft rubber pad layer.

[0013] In a preferred embodiment of the present invention, the lower pile body is a reinforced concrete bored pile body.

[0014] In a preferred embodiment of the present invention, the lower pile body includes a steel cage, reinforced concrete is poured into the steel cage, a horizontal positioning plate is set on the top of the steel cage, the bottom surface of the elastic pad structure is supported on the positioning plate, and the anchor bolt passes through the positioning plate.

[0015] As described above, the variable stiffness anti-floating piles of the present invention have the following beneficial effects:

[0016] In the variable stiffness anti-floating pile of the present invention, the foundation bottom plate and the lower pile body can be connected with variable stiffness through the elastic pad structure and the connector structure. When the foundation bottom plate sinks under the action of load, the connector structure moves downward and is relatively displaced with the anchor bolt, and the elastic pad structure is compressed and deformed. Since a connector cavity is left in the connector structure, the pressure cannot be transmitted to the lower pile body. When the groundwater level is lower than the foundation bottom plate, the vertical compressive stiffness of the variable stiffness anti-floating pile is zero; when the groundwater rises, it gradually bears the buoyancy of the water; the variable stiffness anti-floating pile of the present invention solves the problem of uneven settlement caused by uneven vertical stiffness of the natural foundation and the anti-floating pile when the groundwater is lower than the bottom surface of the basement foundation; the variable stiffness anti-floating pile of the present invention has zero stiffness within the settlement range under vertical pressure, so that the settlement of the entire foundation is considered according to the natural foundation, avoiding uneven settlement of the foundation, avoiding foundation cracking, and ensuring the safety of the foundation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following drawings are only intended to illustrate and explain the present invention, and are not intended to limit the scope of the present invention.

[0018] in:

[0019] Figure 1 : is a schematic diagram of a variable stiffness anti-floating pile of the present invention.

[0020] Figure 2 :for Figure 1 Middle AA section view.

[0021] Figure 3 :for Figure 1 Middle BB cross-section view.

[0022] In the picture:

[0023] 1. Lower pile body; 11. Steel cage; 12. Positioning plate; 13. Pouring hole;

[0024] 2. Connector structure; 21. Connector base plate; 22. Connector riser; 23. Connector cover plate; 24. Connecting column; 25. Stiffener plate; 26. Anchor bar;

[0025] 3. Elastic pad structure;

[0026] 41. Anchor bolt; 42. Fixing nut;

[0027] 5. Foundation slab;

[0028] 6. Cushion layer. DETAILED DESCRIPTION

[0029] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0030] The specific embodiments of the present invention described herein are intended only to illustrate the present invention and are not to be construed as limiting the present invention in any way. In light of the present invention, a skilled person may conceive of any possible variations based on the present invention, all of which should be considered to fall within the scope of the present invention. It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be an intermediate element at the same time. The terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to mechanical or electrical connections, or to internal communication between two elements, and may be directly connected or indirectly connected through an intermediate medium. A person of ordinary skill in the art can understand the specific meanings of the above terms based on the specific circumstances. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are intended only to describe specific embodiments and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0032] like Figures 1 to 3 As shown, the present invention provides a variable stiffness anti-floating pile, comprising a lower pile body 1 and a connector structure 2, wherein a connector cavity is provided in the connector structure 2; an elastic pad structure 3 is provided between the connector structure 2 and the lower pile body 1, and its hardness can support the weight of the connector structure 2 and the concrete thereon; an anchor bolt 41 extending in the direction of the connector structure is connected to the lower pile body 1, and the elastic pad structure 3 and the connector structure 2 can be slidably mounted on the anchor bolt 41; the lower pile body 1 is used to be fixed in the foundation, and the connector structure 2 is used to connect the foundation base plate 5 and the lower pile body 1.

[0033] For some buildings with basements, when designing the anti-floating water level, if the gravity of the building is greater than the water buoyancy and the safety factor is greater than the requirements of the specification, anti-floating piles do not need to be installed as a whole. However, if there are openings in some areas, the local weight cannot resist the local buoyancy, and anti-floating piles need to be installed locally.

[0034] Due to fluctuations in the groundwater level, when the groundwater level is lower than the bottom of the foundation, most of the foundation sits on the natural foundation, with some parts sitting on the anti-floating piles. The anti-floating piles are anchored to the foundation and become compression piles in this state, with greater vertical stiffness, resulting in uneven foundation settlement.

[0035] In the present invention, when the foundation bottom plate 5 sinks under the action of load, the connector structure 2 moves downward and undergoes relative displacement with the anchor bolt 41, and the elastic pad structure 3 (rubber layer) is compressed and deformed. Since a connector cavity is left in the connector structure 2, the pressure cannot be transmitted to the lower pile body 1. When the groundwater level is lower than the foundation bottom plate 5, the vertical compressive stiffness of the variable stiffness anti-floating pile is zero.

[0036] When the groundwater level exceeds the foundation bottom plate 5 and gradually rises upward, the foundation bottom plate 5 gradually moves upward, and after compensating for the original settlement displacement, the upward pulling force is transmitted to the lower pile body 1 through the anchor bolts 41.

[0037] When the groundwater level changes to be lower than the foundation bottom plate 5, the connector structure 2 can move downward freely, and the foundation bottom plate 5 is equivalent to being located on a natural foundation, thus avoiding uneven settlement.

[0038] In the variable stiffness anti-floating pile of the present invention, the foundation bottom plate and the lower pile body can be connected with variable stiffness through the elastic pad structure and the connector structure. When the foundation bottom plate sinks under the action of load, the connector structure moves downward and is relatively displaced with the anchor bolt, and the elastic pad structure is compressed and deformed. Since a connector cavity is left in the connector structure, the pressure cannot be transmitted to the lower pile body. When the groundwater level is lower than the foundation bottom plate, the vertical compressive stiffness of the variable stiffness anti-floating pile is zero; when the groundwater rises, it gradually bears the buoyancy of the water; the variable stiffness anti-floating pile of the present invention solves the problem of uneven settlement caused by uneven vertical stiffness of the natural foundation and the anti-floating pile when the groundwater is lower than the bottom surface of the basement foundation; the variable stiffness pile of the present invention has zero stiffness within the settlement range under vertical pressure, so that the settlement of the entire foundation is considered according to the natural foundation, avoiding uneven settlement of the foundation, avoiding foundation cracking, and ensuring the safety of the foundation.

[0039] Further, if Figure 1 、 Figure 2 As shown, the connector structure 2 includes a connector base plate 21, to which a connector riser 22 extending upward is connected, a connector cover plate 23 is arranged in the connector riser 22, a connecting column 24 is connected between the connector cover plate 23 and the connector base plate 21, and a connector cavity is formed between the connector base plate 21, the connector riser 22 and the connector cover plate 23.

[0040] Further, if Figure 1 、 Figure 2 As shown, a plurality of stiffening plates 25 are further provided between the connector cover plate 23 and the connector bottom plate 21 , and the plurality of stiffening plates 25 are arranged at intervals along the circumference of the connector riser 22 .

[0041] Further, if Figure 1 As shown, the top of the connector riser 22 is connected to a plurality of anchor bars 26 extending upward and obliquely, and the anchor bars 26 are anchored in the foundation slab 5 .

[0042] Further, if Figure 1 、 Figure 2 、 Figure 3 As shown, a first connecting through hole is provided on the connector bottom plate 21, and a second connecting through hole is provided on the elastic pad structure 3. The first end of the anchor bolt passes through the second connecting through hole and the first connecting through hole and is connected to the fixing nut 42, and the second end of the anchor bolt is embedded in the lower pile body 1.

[0043] In this embodiment, the fixing nut 42 is a double nut.

[0044] In this embodiment, the elastic pad structure 3 is a soft rubber pad layer, and its hardness can support the weight of the connector structure 2 and the concrete thereon.

[0045] Furthermore, the lower pile body 1 is a reinforced concrete bored cast-in-place pile body.

[0046] Further, if Figure 1 As shown, the lower pile body 1 includes a steel cage 11, reinforced concrete is poured inside the steel cage 11, a horizontal positioning plate 12 is set on the top of the steel cage 11, the bottom surface of the elastic pad structure 3 is supported on the positioning plate 12, and the anchor bolt 41 passes through the positioning plate 12 and is then sleeved with the elastic pad structure 3 and the connector bottom plate 21.

[0047] In the variable stiffness anti-floating pile of the present invention, the pull-out force borne by the anti-floating pile is calculated according to the anti-floating water level and the anti-floating range; the diameter, length, and reinforcement amount of the lower pile body 1 (lower cast-in-place pile) are determined according to the pull-out force and the standard value of the soil lateral resistance;

[0048] The number and diameter of the anchor bolts 41 are calculated based on the pull-out resistance. In a specific embodiment of the present invention, the number of the anchor bolts 41 is 8 and they are evenly spaced along the circumference.

[0049] When the groundwater level is lower than the basement floor, the settlement of the connector structure 2 is calculated according to the upper load and the natural foundation, and the cavity height H1 and the thickness H2 of the elastic pad structure 3 (rubber pad layer) are determined.

[0050] The bearing capacity of the connector base plate 21 , connector riser 22 , connector column 24 and stiffening plate 25 in the connector structure 2 is calculated based on the pull-out resistance and the tension borne by each anchor bolt.

[0051] The number and diameter of the anchor bars 26 are calculated based on the pull-out resistance.

[0052] The construction process of the variable stiffness anti-floating pile of the present invention is as follows:

[0053] Make the steel cage 11, make the anchor bolt 41, and perforate and plug weld the anchor bolt 41 and the positioning plate 12;

[0054] The connector structure 2 is manufactured in the factory: the connector base plate 21, connector riser 22, connector column 24 and stiffener 25 are welded together, and the anchor bar 26 is welded to the connector riser 22 (steel pipe). A certain gap is left between the connector cover plate 23 and the inner wall of the connector riser 22 to ensure that the connector cover plate 23 can be placed in the connector riser 22. The two are not welded yet.

[0055] On-site construction of the lower pile body 1: First, drill holes, install the steel cage 11, pour concrete to the bottom of the anchor bolt 41, place the anchor bolt 41 and the positioning plate 12, and ensure that the surface of the positioning plate 12 is flush. Pour concrete through the pouring hole 13 and vibrate it to make it dense. Wait until the concrete reaches the required strength.

[0056] Punch holes in the elastic pad structure 3 (rubber pad layer) at the positions of the anchor bolts 41 and place it on the surface of the positioning plate 12;

[0057] Place the connector structure 2 on the elastic pad structure 3 (rubber pad) and tighten the fixing nut 42 (double nut); place the connector cover plate 23 and weld it around the periphery and the inner wall of the connector standpipe 22 to ensure the sealing of the cavity;

[0058] Lay the cushion layer 6 (plain concrete cushion layer, prior art), tie the basement floor steel bars and pour concrete.

[0059] As described above, the variable stiffness anti-floating piles of the present invention have the following beneficial effects:

[0060] In the variable stiffness anti-floating pile of the present invention, the foundation bottom plate and the lower pile body can be connected with variable stiffness through the elastic pad structure and the connector structure. When the foundation bottom plate sinks under the action of load, the connector structure moves downward and is relatively displaced with the anchor bolt, and the elastic pad structure is compressed and deformed. Since a connector cavity is left in the connector structure, the pressure cannot be transmitted to the lower pile body. When the groundwater level is lower than the foundation bottom plate, the vertical compressive stiffness of the variable stiffness anti-floating pile is zero; when the groundwater rises, it gradually bears the buoyancy of the water; the variable stiffness anti-floating pile of the present invention solves the problem of uneven settlement caused by uneven vertical stiffness of the natural foundation and the anti-floating pile when the groundwater is lower than the bottom surface of the basement foundation; the variable stiffness pile of the present invention has zero stiffness within the settlement range under vertical pressure, so that the settlement of the entire foundation is considered according to the natural foundation, avoiding uneven settlement of the foundation, avoiding foundation cracking, and ensuring the safety of the foundation.

[0061] The above description is only an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A variable stiffness anti-floating pile, characterized in that: The invention comprises a lower pile body and a connecting body structure, wherein a connecting body cavity is provided in the connecting body structure; an elastic pad structure is provided between the connecting body structure and the lower pile body, an anchor bolt extending in the direction of the connecting body structure is connected to the lower pile body, and the elastic pad structure and the connecting body structure can be slidably mounted on the anchor bolt; the lower pile body is used to be fixed in the foundation, and the connecting body structure is used to connect the foundation bottom plate and the lower pile body; The connector structure includes a connector base plate, a connector riser extending upward is connected to the connector base plate, a connector cover is arranged inside the connector riser, a connecting column is connected between the connector cover and the connector base plate, and the connector base plate, the connector riser and the connector cover form the connector cavity; When the foundation slab settles under load, the connector structure moves downward, causing relative displacement with the anchor bolts. The elastic pad structure is compressed and deformed. Due to the connector cavity left in the connector structure, the pressure cannot be transmitted to the lower pile body. When the groundwater level is lower than the foundation slab, the vertical compressive stiffness of the variable stiffness anti-floating pile is zero. When the groundwater level exceeds the foundation slab and rises upward, the foundation slab moves upward, and after compensating for the original settlement displacement, the upward pulling force is transmitted to the lower pile body through the anchor bolts; When the groundwater level changes below the foundation slab, the connector structure can move downward freely, and the foundation slab avoids uneven settlement; The top of the connector riser is connected to a plurality of anchor bars extending upward and obliquely; A first connecting through hole is provided on the bottom plate of the connector, a second connecting through hole is provided on the elastic pad structure, the first end of the anchor bolt passes through the second connecting through hole and the first connecting through hole and then is connected to a fixing nut, and the second end of the anchor bolt is embedded in the lower pile body.

2. The variable stiffness anti-floating pile according to claim 1, characterized in that: A plurality of stiffening plates are further arranged between the connector cover plate and the connector bottom plate, and the plurality of stiffening plates are arranged at intervals along the circumference of the connector riser.

3. The variable stiffness anti-floating pile according to claim 1, characterized in that: The elastic pad structure is a soft rubber pad layer.

4. The variable stiffness anti-floating pile according to claim 1, characterized in that: The lower pile body is a reinforced concrete bored cast-in-place pile body.

5. The variable stiffness anti-floating pile according to claim 4, characterized in that: The lower pile body includes a steel cage, reinforced concrete is poured in the steel cage, a horizontal positioning plate is arranged on the top of the steel cage, the bottom surface of the elastic pad structure is supported on the positioning plate, and the anchor bolt passes through the positioning plate.

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