Precast pile

Abstract

The utility model relates to a precast pile which comprises a bottom pile body and a connecting pile body. The bottom pile comprises a first pile body, a pile tip and a first pile splicing connector, and the pile tip and the first pile splicing connector are located at the two ends of the first pile body in the axial direction correspondingly. The connecting pile comprises a second pile body and second pile splicing connectors, the second pile splicing connectors are located at the two ends of the second pile body in the axial direction, and the second pile splicing connector at one end of the connecting pile is connected with the first pile splicing connector of the bottom pile; the first pile body and the second pile body comprise a plurality of pile bodies, each pile body is provided with a first pile section and a second pile section, the direction from the connecting pile to the bottom pile is defined as the first direction, the diameter of the first pile section is linearly increased in the first direction, the diameter of the second pile section is linearly decreased in the first direction, and the maximum diameter of the first pile section is equal to the maximum diameter of the second pile section. The precast pile can effectively improve the friction force between the pile wall and soil around the pile, and the single-pile bearing capacity of a friction pile is improved.

Description

Technical Field

[0001] The present application relates to the technical field of foundation treatment engineering, and in particular to a prefabricated pile. Background Art

[0002] Using precast piles for foundation reinforcement is a common foundation treatment method. Based on their load-bearing characteristics, these piles are primarily categorized as friction piles and end-bearing piles. Friction piles primarily rely on friction between the pile wall and the surrounding soil to provide their bearing capacity. Consequently, friction piles are generally longer, making construction more difficult and increasing foundation treatment investment. Utility Model Content

[0003] In a first aspect, an embodiment of the present application provides a prefabricated pile, which can effectively increase the friction between the pile wall and the soil around the pile, thereby improving the single pile bearing capacity of the friction pile, thereby achieving the goal of reducing the pile length or pile diameter of a single pile at the same reinforcement density, or reducing the number of piles at the same single pile size.

[0004] A prefabricated pile provided in a first aspect of an embodiment of the present application includes: a bottom pile, the bottom pile including a first pile body, a pile tip, and a first pile connection joint, the pile tip and the first pile connection joint being respectively located at two ends of the first pile body in the axial direction;

[0005] A connecting pile, the connecting pile includes a second pile body and a second pile connecting joint, the second pile connecting joints are located at both ends of the second pile body in the axial direction, the second pile connecting joint at one end of the connecting pile is connected to the first pile connecting joint of the bottom pile; the first pile body and the second pile body include a plurality of pile bodies, the pile bodies have a first pile segment and a second pile segment, and the direction from the connecting pile to the bottom pile is defined as a first direction, then the diameter of the first pile segment linearly increases along the first direction, the diameter of the second pile segment linearly decreases along the first direction, and the maximum diameter of the first pile segment is equal to the maximum diameter of the second pile segment.

[0006] In addition, the prefabricated piles provided in the embodiments of the present application may also have the following additional technical features:

[0007] In an optional solution, the bottom pile and the connecting pile have a hollow cavity, the length direction of the cavity extends along the first direction, at least one hole is provided between two adjacent pile bodies of the first pile body and the second pile body, the hole passes through the side wall of the pile body and is connected to the cavity; stones and cement slurry are provided in the cavity.

[0008] In an optional solution, an end wall is provided at the bottom of the pile tip, a through hole is provided on the end wall, the diameter of the through hole is 3 to 5 cm, and the through hole passes through the end wall; or, the cavity extends along the first direction and passes through the end of the pile tip.

[0009] In an optional solution, the through hole is located in the middle of the end wall; the number of the holes is 3 to 4, and the diameter of the holes is 3 to 5 cm.

[0010] In an optional solution, the prefabricated pile has an installation state. In the installation state, the bottom pile and the connecting pile are connected and located below the foundation, the second pile connection joint on one side of the top of the connecting pile is connected to the pile top cap, a pile bottom slurry diffusion area is formed at the bottom of the pile tip, and pile wall cement slurry is formed on the outside of the pile body.

[0011] A second aspect of the embodiments of the present application provides a foundation reinforcement method, wherein the foundation reinforcement method uses the prefabricated piles in the embodiment of the first aspect to perform foundation reinforcement, and the foundation reinforcement method comprises the following steps:

[0012] 1) Based on the properties of the reinforced foundation soil, the precast piles are sunk to the designed pile depth by means of vibration and / or static pressure;

[0013] 2) Filling the cavity of the precast pile with stones whose maximum diameter is slightly smaller than the inner diameter of the cavity until the stones are flush with the top of the pile;

[0014] 3) injecting cement slurry into the cavity in batches to perform segmented grouting;

[0015] 4) Construct the pile top cap. When constructing the pile top cap, the construction sequence needs to be determined taking into account the soil squeezing effect and construction efficiency.

[0016] In an optional scheme, when performing segmented grouting, the first grouting is pile bottom reinforcement grouting to increase the end bearing capacity of the precast pile. When there is groundwater within the pile body, a water pump is used to drain the groundwater entering the cavity before grouting. The grouting height is higher than the groundwater level and is not less than 3m. The grouting after the first grouting is pile body side wall grouting, which is carried out in segments. The grouting height does not exceed 3m each time to fill the gap between the concave outer wall of the pile body and the soil around the pile, thereby increasing the friction between the pile body and the soil around the pile.

[0017] In an optional solution, when performing segmented grouting, the water-cement ratio of the cement slurry is 1:1 to 1:0.5. When the voids in the underlying soil are large and the particles are coarse, a thick slurry is used; when the voids in the underlying soil are small and the particles are fine, a thin slurry is used.

[0018] The beneficial effects of the embodiments of the present application are:

[0019] The precast pile body in the embodiment of the present application includes a first pile segment and a second pile segment. The first and second pile segments form a concave-convex surface structure, which creates a reliable wavy contact between the pile and the surrounding soil, reinforces the soil at the pile bottom, and thus increases the friction between the pile body and the surrounding soil, as well as the bearing capacity of the pile bottom, thereby improving the overall bearing capacity of the single pile. In addition, after filling the cavity of the precast pile with stones and injecting slurry and curing it, the bearing capacity of the pile body itself can be improved, compensating for damage to the pile body during the pile sinking process. The further diffusion of the slurry around the pile also helps to reinforce the soil around the pile, improving the bearing capacity of the surrounding soil around the pile. This is particularly suitable for coarse-grained soil foundations with a certain degree of permeability.

[0020] It should be understood that the foregoing general description and the following detailed description are merely illustrative and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic structural diagram of a bottom pile provided in this application in a specific embodiment;

[0022] Figure 2 A schematic structural diagram of a connecting pile provided in this application in a specific embodiment;

[0023] Figure 3 This is a schematic diagram of the base piles and connecting piles provided for this application after installation and reinforcement.

[0024] Drawing symbols: bottom pile 1, first pile body 11, pile tip 12, first pile joint 13, connecting pile 2, second pile body 21, second pile joint 22, pile body 3, first pile section 31, second pile section 32, cavity 4, hole 41, stone 5, cement slurry in pile 6, pile top cap 7, slurry diffusion area at pile bottom 8, pile wall cement slurry 9.

[0025] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application. DETAILED DESCRIPTION

[0026] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0027] It should be clear that the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0028] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0029] It should be understood that the term "and / or" as used herein is merely a description of the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0030] It should be noted that the directional words such as "upper", "lower", "left", and "right" described in the embodiments of the present application are described based on the angles shown in the accompanying drawings and should not be understood as limiting the embodiments of the present application. In addition, in the context, it should be understood that when it is mentioned that an element is connected to another element "on" or "under", it can not only be directly connected to the other element "on" or "under", but also be indirectly connected to the other element "on" or "under" through an intermediate element.

[0031] like Figure 1-3 As shown, in a first aspect, an embodiment of the present application provides a prefabricated pile, which mainly includes a base pile 1 and a connecting pile 2. The base pile 1 includes a first pile body 11, a pile tip 12, and a first pile joint 13, wherein the pile tip 12 and the first pile joint 13 are respectively located at the two ends of the first pile body 11 along the axial direction; the connecting pile 2 includes a second pile body 21 and a second pile joint 22, wherein the second pile joint 22 is located at the two ends of the second pile body 21 along the axial direction, and the second pile joint 22 at one end of the connecting pile 2 is connected to the first pile joint 13 of the base pile 1; the first pile body 11 and the second pile body 21 include a plurality of pile bodies 3, each of which has a first pile segment 31 and a second pile segment 32. The direction from the connecting pile 2 to the base pile 1 is defined as the first direction, and the diameter of the first pile segment 31 increases linearly along the first direction, while the diameter of the second pile segment 32 decreases linearly along the first direction, and the maximum diameter of the first pile segment 31 is equal to the maximum diameter of the second pile segment 32.

[0032] In this embodiment, the pile body 3 of the precast pile includes a first pile segment 31 and a second pile segment 32. The first pile segment 31 and the second pile segment 32 form a concave-convex surface structure, which creates a reliable wavy contact between the pile and the surrounding soil, reinforces the pile bottom soil, and thus increases the friction between the pile body 3 and the surrounding soil, as well as the pile bottom bearing capacity, thereby improving the overall bearing capacity of the single pile. Specifically, under the same pile diameter conditions, the precast pile can effectively increase the friction between the pile wall and the surrounding soil during operation without increasing the difficulty of pile sinking during construction, thereby improving the bearing capacity of the single pile of the friction pile. This can achieve the goal of reducing the size of the single pile (pile length or pile diameter) at the same reinforcement density, or reducing the number of piles at the same single pile size.

[0033] like Figure 1-3 As shown, in a specific embodiment, the bottom pile 1 and the connecting pile 2 have a hollow cavity 4, the length direction of the cavity 4 extends along the first direction, and at least one hole 41 is provided between two adjacent pile bodies 3 of the first pile body 11 and the second pile body 21, and the hole 41 passes through the side wall of the pile body 3 and is connected to the cavity 4; stones 5 and pile cement slurry 6 are provided in the cavity 4, and the amount of slurry injection can be reduced by adding stones 5 to the cavity 4. The maximum diameter of the stone 5 is slightly smaller than the inner diameter of the cavity 4, so the slurry flow will not be obstructed due to the presence of the stone 5.

[0034] In one embodiment, the bottom of the pile tip 12 is provided with an end wall, which is provided with a through hole having a diameter of 3 to 5 cm and extending through the end wall. Alternatively, the cavity 4 extends along the first direction and extends through the end of the pile tip 12. The through hole is located in the middle of the end wall. The number of holes 41 is 3 to 4, and the diameter of each hole 41 is 3 to 5 cm.

[0035] like Figure 3 As shown, in a specific embodiment, the prefabricated pile has an installed state. In the installed state, the bottom pile 1 and the connecting pile 2 are connected and located below the foundation, the second pile joint 22 on one side of the top of the connecting pile 2 is connected to the pile top cap 7, a pile bottom slurry diffusion area 8 is formed at the bottom of the pile tip 12, and a pile wall cement slurry 9 is formed on the outside of the pile body 3.

[0036] After filling the cavity 4 of the prefabricated pile with stones 5 and injecting slurry to solidify, the bearing capacity of the pile body 3 itself can be improved, compensating for the damage to the pile body during the pile sinking process. Further diffusion of the slurry around the pile is also beneficial to the reinforcement of the soil around the pile, thereby improving the bearing capacity of the surrounding soil around the pile. It is especially suitable for coarse-grained soil foundations with a certain degree of permeability.

[0037] In the embodiment of the first aspect, the pile body (the first pile segment 31 and the second pile segment 32) adopts a concave-convex structure. The wavy contact between the pile and the soil around the pile is theoretically conducive to increasing the friction between the pile body 3 and the soil around the pile. This effect of increasing friction is related to the resilience of the soil. In actual engineering, after the soil between the piles is squeezed by the convex part, gaps may be formed in the concave part. The existence of the gaps affects the friction enhancement effect brought by the wavy contact. At the same time, the pile bottom and the pile wall are reinforced by grouting in the pile body. Grouting in the pile bottom improves the end bearing capacity of the pile, and the reinforcement of the pile wall closes the gaps that may exist between the concave part of the pile body and the soil around the pile, further increasing the friction enhancement brought by the wavy contact. The improvement of the end bearing capacity and the friction of the pile body can greatly improve the bearing capacity of the single pile, thereby reducing the engineering workload of the foundation treatment.

[0038] A second aspect of the embodiments of the present application provides a foundation reinforcement method, which uses the prefabricated piles in the embodiment of the first aspect to reinforce the foundation, and the foundation reinforcement method includes the following steps:

[0039] 1) Based on the properties of the reinforced foundation soil, use vibration and / or static pressure to sink the precast piles to the designed pile depth;

[0040] 2) Fill the cavity 4 of the precast pile with stones 5 whose maximum diameter is slightly smaller than the inner diameter of the cavity 4 until the stones are flush with the top of the pile;

[0041] 3) Injecting cement slurry into the cavity 4 in batches to perform segmented grouting;

[0042] 4) Construct the pile top cap 7. When constructing the pile top cap 7, the construction sequence needs to be determined taking into consideration the soil squeezing effect and construction efficiency.

[0043] In a specific embodiment, when performing segmented grouting, the first grouting is pile bottom reinforcement grouting to increase the end bearing capacity of the prefabricated pile. When there is groundwater within the pile body, a water pump is used to drain the groundwater entering the cavity 4 before grouting, and then grouting is performed. The grouting height is higher than the groundwater level and is not less than 3m; the grouting after the first grouting is completed is the pile body side wall grouting, which is performed in segments, and the grouting height each time does not exceed 3m, so as to fill the gap between the concave outer wall of the pile body and the soil around the pile, thereby increasing the friction between the pile body and the soil around the pile.

[0044] In addition, it should be noted that when performing segmented grouting, the water-cement ratio of the cement slurry is 1:1 to 1:0.5. The specific water-cement ratio can be selected according to the properties of the underlying soil. For example, when the voids in the underlying soil are large and the particles are coarse, a thick slurry is used; when the voids in the underlying soil are small and the particles are fine, a thin slurry is used.

[0045] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A prefabricated pile, characterized in that: include: A bottom pile, comprising a first pile body, a pile tip, and a first pile connection joint, wherein the pile tip and the first pile connection joint are respectively located at two ends of the first pile body in the axial direction; A connecting pile, the connecting pile includes a second pile body and a second pile connecting joint, the second pile connecting joints are located at both ends of the second pile body in the axial direction, the second pile connecting joint at one end of the connecting pile is connected to the first pile connecting joint of the bottom pile; the first pile body and the second pile body include a plurality of pile bodies, the pile bodies have a first pile segment and a second pile segment, and the direction from the connecting pile to the bottom pile is defined as a first direction, then the diameter of the first pile segment linearly increases along the first direction, the diameter of the second pile segment linearly decreases along the first direction, and the maximum diameter of the first pile segment is equal to the maximum diameter of the second pile segment.

2. The precast pile according to claim 1, characterized in that: The bottom pile and the connecting pile have a hollow cavity, the length direction of the cavity extends along the first direction, at least one hole is provided between two adjacent pile bodies of the first pile body and the second pile body, the hole passes through the side wall of the pile body and is connected to the cavity; stones and pile cement slurry are provided in the cavity.

3. The precast pile according to claim 2, characterized in that: The bottom of the pile tip is provided with an end wall, the end wall is provided with a through hole, the diameter of the through hole is 3-5 cm, and the through hole passes through the end wall; or the cavity extends along the first direction and passes through the end of the pile tip.

4. The precast pile according to claim 3, characterized in that: The through hole is located in the middle of the end wall; the number of the holes is 3 to 4, and the diameter of the holes is 3 to 5 cm.

5. The precast pile according to any one of claims 2 to 4, characterized in that: The prefabricated pile has an installed state. In the installed state, the bottom pile and the connecting pile are connected and located below the foundation. The second pile connection joint on one side of the top of the connecting pile is connected to the pile top cap. A pile bottom slurry diffusion area is formed at the bottom of the pile tip, and pile wall cement slurry is formed on the outer side of the pile body.

Images