A bridge abutment foundation structure

Abstract

The utility model discloses a bridge abutment foundation structure, including a high-pressure rotary jet pile vertically buried in the foundation, a prefabricated pipe pile inserted into the high-pressure rotary jet pile, and the tops of the high-pressure rotary jet pile and the prefabricated pipe pile are connected to the cap; it also includes a steel cage, the lower section of the steel cage is built into the upper half of the prefabricated pipe pile, and the upper section thereof extends into the cap. Since the prefabricated pipe pile is inserted into the interior of the high-pressure rotary jet pile, it means that the prefabricated pipe pile is not in direct contact with the soil layer, thereby preventing the pile foundation from changing the internal seepage path of the dam and the dam foundation; at the same time, the prefabricated pipe pile arranged in the high-pressure rotary jet pile can effectively provide support for the cap, thereby improving the bearing capacity of the structure as a whole. Not only that, by arranging a steel cage connected to the prefabricated pipe pile and the cap respectively, the integrity and tensile and bending resistance of the structure can also be effectively enhanced.

Description

Technical Field

[0001] The utility model mainly relates to the technical field of bridge foundations, in particular to a bridge abutment foundation structure. Background Art

[0002] With the gradual improvement of traffic planning and the vigorous promotion of projects to benefit the people, the number of bridges crossing rivers of various levels has increased. Due to various restrictions, bridge abutments may be set on river embankments.

[0003] Traditional abutment pile foundations generally use large-diameter bored cast-in-place piles, which cause great disturbance to the embankment during construction; and during the use of the piles after they are formed, the pile foundation changes the seepage path inside the embankment and the embankment foundation (specifically, the seepage water inside the embankment and the embankment foundation is prone to form a new seepage path along the pile foundation-soil interface, and the new seepage path may connect the soil layers that originally did not experience large-scale vertical seepage), which may cause seepage damage such as piping, resulting in the weakening of the safety and stability of the embankment and abutments.

[0004] High-pressure jet grouting piles are widely used in anti-seepage treatment of foundations. However, simply using high-pressure jet grouting piles as the bearing pile foundation of bridge abutment pile foundations often has insufficient bearing capacity or excessive settlement deformation, which cannot meet the needs of bridge structures.

[0005] Therefore, it is necessary to improve the foundation structure of the abutment so that it can meet both the requirements of foundation anti-seepage and the requirements of bearing capacity. Utility Model Content

[0006] The technical problem to be solved by the utility model is to overcome the deficiencies of the prior art and provide a bridge abutment foundation structure.

[0007] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0008] A bridge abutment foundation structure includes high-pressure rotary jet piles vertically buried in a foundation, prefabricated pipe piles are inserted into the high-pressure rotary jet piles, and the tops of the high-pressure rotary jet piles and the prefabricated pipe piles are both connected to the pedestal; and also includes a steel cage, the lower section of the steel cage is embedded in the upper half of the prefabricated pipe piles, and the upper section of the steel cage extends into the pedestal.

[0009] As a further improvement of the above technical solution:

[0010] A plurality of the high-pressure jet-jet piles are distributed in an array.

[0011] The prefabricated pipe pile is coaxially arranged with the high-pressure rotary jet pile.

[0012] The pile bottom of the prefabricated pipe pile is 1m higher than the pile bottom of the high-pressure rotary jet pile.

[0013] The prefabricated pipe pile is configured as a PHC pipe pile and is provided with a closed steel pile tip.

[0014] A cushion layer is arranged between the bearing platform and the foundation.

[0015] The steel cage is provided with a disc-shaped steel supporting plate at the lower end.

[0016] The inner cavity of the prefabricated pipe pile is poured with plain concrete and slightly expansive concrete in layers, wherein the plain concrete is located below the steel support plate and the slightly expansive concrete is located above the steel support plate.

[0017] The upper section of the steel cage is configured to be in a trumpet shape that gradually expands from bottom to top.

[0018] The steel cage is provided with a steel mesh at the junction of the lower section and the upper section.

[0019] Compared with the prior art, the advantages of the utility model are:

[0020] Since the prefabricated pipe piles are inserted inside the high-pressure jet grouting piles, it means that the prefabricated pipe piles are not in direct contact with the soil layer, thus preventing the pile foundation from changing the seepage path inside the dam and the dam foundation; at the same time, the prefabricated pipe piles set in the high-pressure jet grouting piles can effectively provide support for the cap, thereby improving the bearing capacity of the structure as a whole. In addition, by setting up steel cages connected to the prefabricated pipe piles and the cap respectively, the integrity and tensile and bending resistance of the structure can be effectively enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the elevation structure of the abutment foundation structure;

[0022] Figure 2 It is a schematic diagram of the connection between the prefabricated pipe pile and the cap;

[0023] The numbers in the figure represent: 1. High-pressure jet jet piles; 2. Precast pipe piles; 3. Capping platform; 4. Steel cage; 41. Lower section; 42. Upper section; 43. Steel support plate; 44. Steel mesh; 45. Plain concrete; 46. Micro-expansive concrete; 5. Cushion layer. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0025] Example

[0026] like Figure 1 and Figure 2As shown, the abutment foundation structure of this embodiment is suitable for the case where the abutment is set on the river bank, and it includes a plurality of high-pressure jet grouting piles 1 vertically buried in the foundation and distributed in an array. Specifically, a prefabricated pipe pile 2 with a diameter smaller than that of the high-pressure jet grouting pile 1 is coaxially inserted into each high-pressure jet grouting pile 1; a cushion layer 5 is laid on the foundation surface, and a cap 3 connected to the top of the high-pressure jet grouting pile 1 and the prefabricated pipe pile 2 is provided on the cushion layer 5. The abutment foundation structure also includes a steel cage 4, the lower section 41 of the steel cage 4 is built into the upper half of the prefabricated pipe pile 2, and the upper section 42 thereof extends into the cap 3, and is cast together with the concrete of the cap 3 to form a whole. By adopting the composite pile foundation of the prefabricated pipe pile 2 inserted in the high-pressure rotary jet pile 1 as the main bearing member, the prefabricated pipe pile 2 is a reinforcing structure of the high-pressure rotary jet pile 1, which can improve the bearing capacity of the pile foundation, thereby effectively reducing the settlement deformation of the abutment 3; at the same time, the combination of the prefabricated pipe pile 2 and the high-pressure rotary jet pile 1 as the abutment pile foundation can prevent the formation of a new seepage path due to the pile foundation-soil interface, thereby avoiding the pipe surge that may be caused by the installation of the abutment. In addition, the high-pressure rotary jet pile 1 can fill the voids that may exist in the dam and the dam foundation to a certain extent, thereby reinforcing the dam and the foundation. This embodiment adopts the design concept of "multi-pile large abutment", which can spread the bridge load more evenly into the foundation, thereby further reducing the adverse effects of stress concentration on the dam.

[0027] In this embodiment, the pile bottom of the prefabricated pipe pile 2 is 1m higher than the pile bottom of the high-pressure rotary jet pile 1, so that the high-pressure rotary jet pile 1 can generate good pile end resistance to the prefabricated pipe pile 2. At the same time, because the high-pressure rotary jet pile 1 forms a wrap around the bottom end of the prefabricated pipe pile 2, the anti-seepage effect can be improved. The prefabricated pipe pile 2 uses a PHC pipe pile with mature technology and high standardization. The diameter of the PHC pipe pile is small. Since there is generally no hard soil or rock layer within the range of the dam, the PHC pipe pile can be constructed by static pressure method, thereby reducing the disturbance and damage to the dam. In order to facilitate the pressing of the PHC pipe pile into the high-pressure rotary jet pile 1 and prevent the soil from entering the inner cavity, the bottom end of the PHC pipe pile is set to a closed steel pile tip. More specifically, the diameter of the PHC pipe pile body is 500mm, and a closed cross steel pile tip is used. The diameter of the high-pressure rotary jet pile 1 is 900mm. In addition, the inner cavity of the prefabricated pipe pile 2 is poured with plain concrete 45 and micro-expansive concrete 46 in layers, wherein the plain concrete 45 is located below the steel support plate 43 and the micro-expansive concrete 46 is located above the steel support plate 43. The micro-expansive concrete 46 expands to a certain extent during the hardening process, which can enhance the friction strength between the micro-expansive concrete 46 and the inner wall of the prefabricated pipe pile 2, thereby improving the connection strength between the cap 3 and the prefabricated pipe pile 2; the plain concrete 45 can improve the impermeability of the interior of the pipe pile.

[0028] In this embodiment, a disc-shaped steel support plate 43 is provided at the lower end of the steel cage 4, and the steel support plate 43 serves as a bottom mold for pouring the micro-expansive concrete 46. The upper section 42 of the steel cage 4 is configured to be a trumpet-shaped shape that gradually expands from bottom to top. The upper portion of the steel cage 4 is configured to be a trumpet-shaped shape to strengthen the connection strength between it and the cap 3. A star-shaped steel mesh 44 is provided at the junction of the lower section 41 and the upper section 42 of the steel cage 4. The diameter of each steel mesh 44 is slightly smaller than the outer diameter of the PHC pile, and the diameter of each steel support plate 43 matches the inner diameter of the PHC pile. In order to ensure that no sinking occurs when pouring the micro-expansive concrete 46, the steel mesh 44 and the steel support plate 43 are welded to the corresponding steel cage 4.

[0029] During the specific construction process, the high-pressure rotary jet pile 1 adopts the double-tube method for construction, and the deviation between the drilling position and the design position is no more than 50mm, and the verticality of the pile body does not exceed 1 / 100. After the construction age of the high-pressure rotary jet pile 1 reaches the design requirements, the PHC pipe pile is inserted into the high-pressure rotary jet pile 1 by the static pressure method. When inserting the PHC pipe pile by the static pressure method, pay attention to the monitoring of the verticality of the pile body and the horizontal and vertical displacement of the pile top to ensure that the PHC pipe pile and the high-pressure rotary jet pile 1 are coaxial and driven to the designed depth. After the construction of each PHC pipe pile is completed, the cushion layer 5 and the base 3 are poured in turn, and the upper section 42 of the steel cage 4 extends into the base 3 and is poured together with the base concrete to strengthen the connection between the PHC pipe pile and the base 3.

[0030] Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the art can use the above disclosed technical content to make many possible changes and modifications to the technical solution of the present invention without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention should fall within the scope of protection of the technical solution of the present invention.

Claims

1. A bridge abutment foundation structure, characterized in that: The invention comprises a high-pressure jet grouting pile (1) vertically buried in a foundation, a prefabricated pipe pile (2) inserted into the high-pressure jet grouting pile (1), and the top ends of the high-pressure jet grouting pile (1) and the prefabricated pipe pile (2) are both connected to a cap (3); and also comprises a steel cage (4), the lower section (41) of the steel cage (4) being embedded in the upper section of the prefabricated pipe pile (2), and the upper section (42) of the steel cage extending into the cap (3).

2. The abutment foundation structure according to claim 1, characterized in that: A plurality of the high-pressure jet grouting piles (1) are distributed in an array.

3. The abutment foundation structure according to claim 1, characterized in that: The prefabricated pipe pile (2) is coaxially arranged with the high-pressure jet-jet pile (1).

4. The abutment foundation structure according to claim 1, characterized in that: The pile bottom of the prefabricated pipe pile (2) is 1 m higher than the pile bottom of the high-pressure rotary jet pile (1).

5. The abutment foundation structure according to claim 1, characterized in that: The prefabricated pipe pile (2) is configured as a PHC pipe pile and is provided with a closed steel pile tip.

6. The abutment foundation structure according to claim 1, characterized in that: A cushion layer (5) is provided between the support platform (3) and the foundation.

7. The abutment foundation structure according to claim 1, characterized in that: The steel cage (4) is provided with a disc-shaped steel support plate (43) at the lower end thereof.

8. The abutment foundation structure according to claim 7, characterized in that: The inner cavity of the prefabricated pipe pile (2) is poured with plain concrete (45) and micro-expansive concrete (46) in layers, wherein the plain concrete (45) is located below the steel support plate (43) and the micro-expansive concrete (46) is located above the steel support plate (43).

9. The abutment foundation structure according to claim 1, characterized in that: The upper section (42) of the steel cage (4) is configured to be in a trumpet shape that gradually expands from bottom to top.

10. The abutment foundation structure according to claim 9, characterized in that: The steel cage (4) is provided with a steel mesh (44) at the junction of the lower section (41) and the upper section (42).

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