Assembly type anti-freezing pile pulling foundation for overhead transmission line in permafrost region

Abstract

The utility model relates to the field of pile foundation engineering in permafrost regions, and particularly discloses an assembly type anti-freezing pile pulling foundation for overhead transmission lines in permafrost regions, which comprises a strip-shaped base, a regular conical upright post, a heat insulation plate and a bearing platform which are sequentially arranged from bottom to top, the upper part of the regular conical upright post is a hollow circular truncated cone, and the lower part of the regular conical upright post is a hollow cylinder; the top end of the regular-cone-shaped stand column is sequentially connected with a heat insulation plate and a bearing platform through bolts, the pile bottom is connected with a strip-shaped base through a flange, the bearing platform and the strip-shaped base are each of a prefabricated assembly type structure, and the heat insulation plate is an asbestos plate. The pile foundation is a hollow body and is light in weight, the regular-cone-shaped stand columns can fundamentally reduce tangential frost heaving force, so that upward pulling displacement of the pile body is reduced, the heat insulation plates can effectively prevent radiation heat from being transmitted to soil around the pile in warm seasons, the frozen soil upper limit of the soil around the pile is improved, the stability of the soil around the pile is enhanced, meanwhile, all the components can be flexibly disassembled and assembled, and construction is convenient. Construction is fast and convenient, and application and popularization are facilitated.

Description

Technical Field

[0001] This utility model relates to the field of pile foundation engineering in permafrost regions, and in particular to a prefabricated anti-freezing and pull-out pile foundation for overhead power transmission lines in permafrost regions. Background Technology

[0002] The load-bearing structure of overhead transmission line pile foundations differs from that of other structures, primarily subjected to uplift loads. The potential frost-uplift force present in permafrost foundations undoubtedly increases the risk of uplift failure. Currently, power pole tower foundations in permafrost regions commonly employ either directly buried straight-column pile foundations or bored cast-in-place pile foundations. Directly buried straight-column pile foundations have poor frost-uplift resistance and frequently suffer frost-uplift failure; traditional bored cast-in-place pile foundations have long construction cycles, are difficult to construct in high-altitude permafrost regions, and their construction can cause some damage to the ecological environment, exacerbating permafrost degradation. Utility Model Content

[0003] The purpose of this utility model is to provide a prefabricated anti-freezing and pull-out pile foundation for overhead transmission lines in permafrost areas. It has the characteristics of fast construction speed, low overall cost, good anti-freezing and pull-out performance, and small disturbance to the permafrost strata. It can reduce the shear stress of pile sides and the frost pull-out displacement of pile foundation in permafrost areas.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a prefabricated anti-freezing pile foundation for overhead transmission lines in permafrost areas, comprising a prefabricated strip base plate, a conical column, and a pile cap arranged sequentially from bottom to top; the upper part of the conical column is a hollow frustum, and the lower part is a hollow cylinder, and the hollow frustum and the hollow cylinder are integrally formed.

[0005] The hollow frustum is placed within the active layer, and the hollow cylinder is placed within the permafrost layer. The hollow frustum is used to reduce the shear stress on the pile side when the soil in the active layer freezes and heaves.

[0006] Preferably, a heat insulation plate is provided between the bottom of the support platform and the top of the hollow truncated cone.

[0007] Optionally, the bottom of the support platform is fixedly connected to the top of the hollow truncated cone by bolts.

[0008] Optionally, the bottom surface of the hollow cylinder is connected to the prefabricated strip base plate via a flange.

[0009] Preferably, the support platform, the conical column, and the prefabricated strip base plate are all prefabricated structures.

[0010] Compared with the prior art, this utility model has the following advantages:

[0011] 1. All components are prefabricated, and the prefabricated components can effectively ensure quality and make construction fast and convenient.

[0012] 2. The upper part of the conical column adopts a hollow frustum design and the lower part adopts a hollow cylinder design, which reduces the lateral shear stress of the pile in the active layer and increases the stability of the pile foundation.

[0013] 3. A heat insulation board is installed between the top of the conical column and the foundation, which effectively reduces the downward conduction of heat, thereby increasing the upper limit of the frozen soil. The heat insulation board is made of asbestos board, which is inexpensive. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model.

[0015] Figure 2 This is a schematic diagram of the force decomposition of a conical pile.

[0016] Explanation of reference numerals in the attached figures:

[0017] 1- Bolt, 2- Foundation, 3- Insulation board, 4- Hollow frustum, 5- Upper limit of frozen soil, 6- Hollow cylinder, 7- Flange, 8- Precast strip base plate, 9- Movable layer, 10- Permafrost layer. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0019] A prefabricated anti-freezing pile foundation for overhead transmission lines in permafrost regions includes a prefabricated strip base plate 8, a conical column, and a pile cap 2 arranged sequentially from bottom to top. The upper part of the conical column is a hollow frustum 4, which is placed inside an movable layer 9. The lower part of the conical column is a hollow cylinder 6, which is placed inside a permafrost layer 10. The hollow frustum 4 and the hollow cylinder 6 are integrally formed.

[0020] Based on the above technical solution, a heat insulation plate 3 is provided between the bottom of the pile cap 2 and the top of the hollow truncated cone 4. The heat insulation plate 3 can effectively prevent radiant heat from being transferred to the soil around the pile during the warm season.

[0021] More specifically, the top of the hollow truncated cone 4 is connected to the heat insulation plate 3 and the support 2 by bolts in sequence, and the bottom of the hollow cylinder 6 is connected to the prefabricated strip base plate 9 by flange 7.

[0022] Based on the above technical solution, the foundation 2, the conical column, and the prefabricated strip base plate 8 are all prefabricated structures.

[0023] More specifically, the force diagram of a conical column is as follows: Figure 2 As shown, the condition for whether a pile foundation is pulled up depends on the magnitude of the resultant upward and downward forces acting on the pile foundation.

[0024] Depend on Figure 2 It can be seen that the magnitudes of the upward and downward resultant forces acting on the pile foundation are as follows:

[0025]

[0026] In the formula: For external loads; For the self-weight of the pile foundation; This refers to tangential frost heave force; Normal frost heave force; Frictional resistance in permafrost regions; It is the base angle; The lateral surface area of ​​the cone-shaped portion; The lateral surface area of ​​the cylindrical portion within the permafrost region; This represents the lateral surface area of ​​the cylindrical portion within the unfrozen soil region.

[0027] In the above formula, the conical pile The lateral area is smaller than that of a cylindrical pile with the same diameter and height, while the two pile shapes... Since they are equal, it can be known that the cone pile is subjected to... The force exerted on a cylindrical pile of equal diameter is smaller than that on a cylindrical pile of equal diameter. Furthermore, due to the presence of tapered piles... Ignoring the effect of the cone angle on the self-weight of the pile foundation The influence of external loads on two types of piles and Since they are equal, it can be known that the cone pile is subjected to... The force exerted on a cylindrical pile of equal diameter is greater than that on a cylindrical pile of equal diameter. Therefore, tapered pile foundations can utilize their geometric advantages to prevent pile foundation frost pull-out.

[0028] As shown above, the prefabricated anti-freezing pile foundation for overhead transmission lines in permafrost areas provided in this implementation is particularly suitable for the permafrost areas of the Qinghai-Tibet Plateau, where the upper limit of the permafrost is about 3m. During construction, the hollow cylindrical part can be completely inserted into the permafrost layer.

[0029] This utility model uses a hollow truncated cone 4 to penetrate the active layer. Because it is truncated cone-shaped, it can effectively reduce the shear stress on the pile side when the soil in the active layer freezes and heaves. A heat insulation plate 3 is provided between the hollow truncated cone 4 and the pile cap 2, which effectively reduces the downward conduction of heat, thereby increasing the upper limit of frozen soil and increasing the stability of the pile foundation.

[0030] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A prefabricated frost-resistant pull-out pile foundation for overhead transmission lines in permafrost regions, characterized in that, It includes a prefabricated strip base plate (8), a conical column and a support platform (2) arranged sequentially from bottom to top; the upper part of the conical column is a hollow frustum (4) and the lower part is a hollow cylinder (6), and the hollow frustum (4) and the hollow cylinder (6) are integrally formed; the hollow frustum (4) is placed in the movable layer (9) and the hollow cylinder (6) is placed in the permafrost layer (10).

2. The prefabricated anti-freezing pile foundation for overhead transmission lines in permafrost regions according to claim 1, characterized in that, A heat insulation plate (3) is provided between the bottom of the support platform (2) and the top of the hollow truncated cone (4).

3. The prefabricated frost-resistant pull-out pile foundation for overhead transmission lines in permafrost regions according to claim 1, characterized in that, The bottom of the support platform (2) is fixedly connected to the top of the hollow truncated cone (4) by bolts.

4. The prefabricated frost-resistant pull-out pile foundation for overhead transmission lines in permafrost regions according to claim 1, characterized in that, The bottom surface of the hollow cylinder (6) is connected to the prefabricated strip base plate (8) via a flange (7).

5. The prefabricated frost-resistant pull-out pile foundation for overhead transmission lines in permafrost regions according to claim 1, characterized in that, The foundation (2), the conical column, and the prefabricated strip base plate (8) are all prefabricated structures.

Images