Composite bearing structure for grouting around prefabricated pipe pile

Abstract

The utility model relates to a composite bearing structure for grouting around a prefabricated pipe pile, which is suitable for the situation that the prefabricated pipe pile is adopted as a lower structure of an assembly type structure, but the requirement for bearing capacity cannot be met. The grouting steel floral tubes are distributed around the prefabricated pipe pile according to a certain angle, a circle of grouting steel floral tubes are arranged around the outer circle of the prefabricated pipe pile, the center of the prefabricated pipe pile serves as the circle center of the multiple grouting steel floral tubes, grout is injected into the grouting steel floral tubes and between the grouting steel floral tubes and the prefabricated pipe pile, and the stress of soil around the pile is enhanced through high-pressure grouting of the grout. The friction resistance around the pile is improved, the grouting body, the prefabricated pipe pile and the grouting steel floral pipe are compounded into a bearing structure, the bearing capacity requirement of an upper structure is met, reinforcing and remedying of insufficient bearing capacity of the prefabricated pipe pile are achieved, and good economic and technical benefits are achieved.

Description

Technical Field

[0001] The utility model belongs to the technical field of highways and mainly relates to a composite bearing structure of prefabricated pipe piles with grouting around the piles. Background Art

[0002] Prefabricated pipe piles have long been widely used for soft foundation treatment. However, in recent years, with the continuous application of assembled highway structures, new structures such as pile-slab roadbeds and assembled bridges have used a large number of prefabricated pipe piles, which has continuously simplified the difficulty of highway construction and improved the efficiency of highway construction. However, during the construction of prefabricated pipe piles, special strata such as pebble layers are often encountered, which cannot be driven to the designed depth, or are close to houses, etc. Excessive hammering will cause secondary disasters, resulting in insufficient bearing capacity of the pipe piles. Utility Model Content

[0003] The utility model provides a composite bearing structure with grouting around prefabricated pipe piles; the structure increases soil stress around the piles and improves the bearing capacity of the pipe pile foundation by grouting around the prefabricated pipe piles to meet the designed bearing capacity of the pile foundation.

[0004] The technical solution provided by the utility model is:

[0005] A composite bearing structure with grouting around prefabricated pipe piles comprises prefabricated pipe piles and grouting steel flower pipes; the grouting steel flower pipes are arranged in a circle around the outer circle of the prefabricated pipe piles, a plurality of grouting steel flower pipes are centered on the center of the prefabricated pipe piles, and slurry is injected inside the grouting steel flower pipes and between the grouting steel flower pipes and the prefabricated pipe piles to form a grouting body, which forms a composite bearing structure with the grouting steel flower pipes and the prefabricated pipe piles.

[0006] As a further technical solution, the grouting holes of the grouting steel flower pipe are arranged in a spiral shape along the outer wall of the grouting steel flower pipe.

[0007] As a further technical solution, a grouting hole is drilled at a set distance along the axis of the steel pipe and at a rotation of 45° along the radial direction of the steel pipe.

[0008] As a further technical solution, the bottom of the grouting steel flower pipe is a guide cap cone head.

[0009] As a further technical solution, the distance between the outer wall of each grouting steel flower pipe and the outer wall of the prefabricated pipe pile is equal.

[0010] As a further technical solution, the distance is 0.4m.

[0011] As a further technical solution, a centering frame is arranged at a set distance on the outer wall of each grouting steel flower pipe.

[0012] As a further technical solution, the length of the grouting steel flower pipe is the same as the length of the prefabricated pipe pile.

[0013] As a further technical solution, the distribution angle of the grouting steel flower pipe around the prefabricated pipe pile is determined according to the spacing between the grouting hole of the prefabricated pipe pile and the prefabricated pipe pile and the diffusion radius of the steel flower pipe grouting.

[0014] As a further technical solution, the upper and lower grouting steel flower pipes are connected by a sleeve.

[0015] Beneficial technical effects of the utility model:

[0016] The utility model arranges a grouting steel flower tube around the prefabricated pile, and then performs grouting inside the grouting steel flower tube and between the grouting steel flower tube and the prefabricated pipe pile to form a grouting body, and the grouting body, the grouting steel flower tube and the prefabricated pipe pile form a composite bearing structure; thereby increasing the soil stress around the pile, improving the friction resistance around the pile, and effectively improving the performance of the contact surface, so that the slurry around the pile and the prefabricated pipe pile form a composite bearing structure, thereby improving the bearing capacity of the pipe pile foundation and meeting the bearing capacity requirements of the upper structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a plan view of the utility model;

[0018] Figure 2 It is a schematic elevation diagram of the utility model;

[0019] Figure 3 This is a schematic diagram of the structure of the steel flower tube of the utility model;

[0020] The serial numbers in the above figure are: 1-prefabricated pipe pile, 2-grouting steel flower pipe, 3-ground surface, 4-seamless steel pipe, 5-grouting small hole, 6-centering frame, 7-casing, 8-guide cap cone head. DETAILED DESCRIPTION

[0021] In order to make the technical means, innovative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited thereto.

[0022] like Figure 1-Figure 3As shown, the utility model provides a composite bearing structure of grouting around prefabricated pipe piles, including a prefabricated pipe pile 1 that has been driven into the foundation, a grouting steel flower pipe 2 drilled and placed around it, and a grouting body after high-pressure grouting, the grouting body, the prefabricated pipe pile 1, and the grouting steel flower pipe 2 together form a composite bearing structure, that is, the grouting steel flower pipe 2 in this embodiment is a part of the bearing structure; when the prefabricated pipe pile cannot be constructed to the designed depth due to various reasons and cannot reach the designed bearing capacity, but the upper structure has relatively high requirements for bearing capacity, and the prefabricated pipe pile is used as a lower structure, and the bearing capacity cannot be improved by measures such as increasing the density of pipe piles. Around the prefabricated pipe pile 1 that cannot be constructed to the designed depth, the grouting steel flower pipe 2 is distributed at a certain angle, and the soil stress is strengthened through high-pressure grouting to form a composite bearing structure to meet the bearing capacity requirements of the upper structure.

[0023] The distance between the grouting steel flower pipe 2 and the outer wall of the prefabricated pipe pile 1 is related to the diffusion radius of the cement slurry. The diffusion radius of the secondary grouting of the steel flower pipe is generally 0.5m. In order to improve the combination of the grouting body and the prefabricated pipe pile 1, the distance between the steel flower pipe 2 of the utility model and the outer wall of the prefabricated pipe pile 1 is 0.4m.

[0024] The distribution angle of the grouting steel flower pipe around the pipe pile should be determined according to the spacing between the grouting hole and the prefabricated pipe pile and the diffusion radius of the steel flower pipe grouting, so that the cement slurry can diffuse and fill the soil around the pile as much as possible. In this embodiment, the grouting steel flower pipe 2 is distributed around the prefabricated pipe pile 1, with the center of the prefabricated pipe pile 1 as the center of the circle, and the steel flower pipe 2 is arranged at a distribution angle of 60°.

[0025] The depth of the grouting hole needs to be determined according to the stratum in which it is located, and is generally the same as the driving depth of the precast pipe piles. When encountering strata with large voids such as soft rock layers, whether to penetrate the stratum should be considered comprehensively based on the bearing capacity requirements and the depth of the soft rock layer.

[0026] The length of the grouting steel flower pipe 2 is the same as that of the prefabricated pipe pile 1. When encountering a stratum with large gaps such as a soft rock layer, in order to avoid poor grouting effect caused by slurry loss, slurry bags can be set above and below the soft rock layer to penetrate the pebble layer.

[0027] The grouting steel flower pipe 2 can be made of a φ50×2mm seamless steel pipe 4, and φ8mm grouting holes 5 are drilled every 8cm along the axis of the steel pipe and every 45° along the radial direction of the steel pipe 4. The grouting holes 5 are arranged in a spiral shape around the steel pipe. The grouting holes 5 are sealed with special tape or gel, and the steel pipe must be derusted before production.

[0028] The bottom of the steel pipe 4 is sharpened and welded to form a guide cap cone 8. To ensure the verticality of the steel pipe, a centering frame 6 is set every 3.0m on the steel pipe. The purpose of setting the centering ring 6 is mainly: the diameter of the grouting hole is generally larger than that of the steel pipe 2. The centering frame 6 is welded outside the steel pipe. Generally, 3 are set, and the interval is 120 degrees. When the steel pipe is put down, there are peripheral centering frames 6 to ensure that the steel pipe is located in the middle of the grouting hole instead of being attached to the wall of the grouting hole. Grouting can be more uniform.

[0029] When the length of the steel pipe 4 cannot meet the designed length, multiple steel pipes 4 can be connected, and a steel pipe with a slightly larger inner diameter is used as a sleeve 7 at the connection between two steel pipes 4, and the steel pipes are connected by welding.

[0030] In order to expand the grouting diffusion radius and improve the grouting effect, the grouting adopts the scheme of secondary grouting of steel pipe. The slurry strength is not less than M30. During grouting, an expansion agent of 1.5-2% of cement should be added to improve the grouting effect. The steel pipe grouting adopts secondary grouting. The first grouting is grouting between the steel pipe and the drill hole, and the grouting pressure is not less than 0.5MPa; the second grouting is splitting grouting, grouting in the steel pipe, and the grouting pressure is not less than 2MPa. The second grouting should be sealed at the pipe head and the grouting pipe should be reserved. The optimal mix ratio and grouting pressure should be determined according to the test, and the slurry strength is M30. During grouting, an expansion agent of 1.5-2% of cement should be added to improve the grouting effect.

[0031] Finally, it should be noted that relational terms such as first and second are merely used to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any actual relationship or order between these entities or operations.

[0032] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A composite bearing structure with grouting around prefabricated pipe piles, characterized in that: It includes prefabricated pipe piles and grouting steel flower pipes; the grouting steel flower pipes are arranged around the outer circle of the prefabricated pipe piles, and multiple grouting steel flower pipes are centered on the center of the prefabricated pipe piles, and slurry is injected inside the grouting steel flower pipes and between the grouting steel flower pipes and the prefabricated pipe piles.

2. The composite bearing structure of prefabricated pipe piles with grouting around them as claimed in claim 1, characterized in that: The grouting holes of the grouting steel flower pipe are arranged in a spiral shape along the outer wall of the grouting steel flower pipe.

3. The composite bearing structure of prefabricated pipe piles with grouting around them as claimed in claim 2, characterized in that: A grouting hole is drilled at a set distance along the axis of the grouting steel pipe and every 45° rotation along the radial direction of the grouting steel pipe.

4. The composite bearing structure of prefabricated pipe piles with grouting around them as claimed in claim 1, characterized in that: The bottom of the grouting steel flower pipe is a guide cap cone head.

5. The composite bearing structure of prefabricated pipe piles with grouting around them as claimed in claim 1, characterized in that: The distance between the outer wall of each grouting steel flower pipe and the outer wall of the prefabricated pipe pile is equal.

6. The composite bearing structure of prefabricated pipe piles with grouting around them as claimed in claim 5, characterized in that: The distance is 0.4m.

7. The composite bearing structure of prefabricated pipe piles with grouting around them as claimed in claim 1, characterized in that: A centering frame is arranged at a set distance on the outer wall of each grouting steel flower pipe.

8. The composite bearing structure of prefabricated pipe piles with grouting around them as claimed in claim 1, characterized in that: The length of the grouting steel flower pipe is the same as that of the prefabricated pipe pile.

9. The composite bearing structure of prefabricated pipe piles with grouting around them as claimed in claim 1, characterized in that: The distribution angle of the grouting steel flower pipe around the prefabricated pipe pile is determined according to the spacing between the grouting hole of the prefabricated pipe pile and the prefabricated pipe pile and the diffusion radius of the grouting of the steel flower pipe.

10. The composite bearing structure of prefabricated pipe piles with grouting around them as claimed in claim 1, characterized in that: The upper and lower grouting steel flower pipes are connected by sleeves.

Images