Construction method of large-diameter steel pipe composite pile

Abstract

This invention relates to the field of steel pipe pile technology, and in particular to a construction method for large-diameter steel pipe composite piles. The method is characterized by: an opening at the bottom of the large-diameter steel pipe, making the bottom of the pipe a soil penetration point; mixing blades on the outer wall of the bottom of the large-diameter steel pipe; and a grouting nozzle on the steel pipe body below the mixing blades. The large-diameter steel pipe is rotated and lowered simultaneously, while cement grout is sprayed into the soil surrounding the large-diameter steel pipe through the grouting nozzle. The soil at the pile head is mixed with the cement grout to form cement-soil mixture. During the lowering process of the large-diameter steel pipe, the soil at the pile head enters the pipe to form a soil plug, creating a composite pile foundation with a mixing pile on the outer periphery and soil inside the large-diameter steel pipe. The advantages of this invention are: significantly reduced resistance during the mixing and lowering of the steel pipe; adaptability to large-diameter and deep pile foundations; and the use of a high-bearing-capacity steel-concrete composite structure to bear the upper load, significantly reducing the cross-sectional area of ​​the core pile.

Description

Technical Field

[0001] This invention relates to the field of steel pipe pile technology, and in particular to a construction method for large-diameter steel pipe composite piles. Background Technology

[0002] Currently, existing steel pipe composite piles consist of a steel pipe, concrete inside the steel pipe, and cement-soil outside the steel pipe. The steel pipe is inserted into the cement-soil outside the steel pipe, and the concrete inside the steel pipe fills the inside of the steel pipe.

[0003] There are two common construction methods for steel pipes. One is to first use the mixing pile construction process to construct the cement soil outside the steel pipe, and then insert the steel pipe into the cement soil outside the steel pipe. The other is to use construction equipment to mix and sink the steel pipe and the mixing pile simultaneously, such as the construction method disclosed in the invention patent with publication number CN116397631A.

[0004] For the first construction scheme, to prevent cement and soil from entering the steel pipe during insertion, the bottom of the steel pipe is designed as a closed structure to reserve space for subsequent concrete pouring. For the second construction scheme, since the steel pipe is constructed using a mixing pile, a rotating mixing drill bit must be installed at its bottom to rotate synchronously with the sinking of the steel pipe. Therefore, the bottom of the steel pipe is also effectively a closed structure.

[0005] Based on this, the bottom of the steel pipe in current steel pipe composite piles is mostly a closed structure. However, when the diameter of the steel pipe is large, especially during mixing and sinking, the sinking resistance is large, the soil squeezing effect is severe, and the pile driving is difficult. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of the prior art by providing a construction method for large-diameter steel pipe composite piles. This method uses large-diameter steel pipes as the core of the steel pipe composite pile, forming a large-diameter steel pipe composite pile. The bottom of the steel pipe adopts an open structure to reduce the resistance during the mixing and sinking of the steel pipe composite pile, and to reduce the soil squeezing effect during the sinking of the steel pipe composite pile, thus forming a large-diameter steel pipe composite pile.

[0007] The objective of this invention is achieved through the following technical solutions: A construction method for large-diameter steel pipe composite piles, characterized by the following steps: An opening is provided at the bottom of a large-diameter steel pipe to form a soil inlet. A mixing blade is provided on the outer wall of the bottom of the large-diameter steel pipe, and a grouting nozzle is opened on the steel pipe body below the mixing blade. The large-diameter steel pipe is rotated and lowered while cement grout is sprayed into the soil around the large-diameter steel pipe through the grouting nozzle. The soil at the pile head is mixed with the cement grout to form cement soil. During the sinking process of the large-diameter steel pipe, the soil at the pile head enters the large-diameter steel pipe to form a soil plug, forming a composite pile foundation with a mixing pile on the outer periphery of the large-diameter steel pipe and soil inside the large-diameter steel pipe.

[0008] According to the bearing capacity requirements of large-diameter steel pipe composite piles, the soil inside the large-diameter steel pipe is cleaned, and then a certain height of concrete is poured into the inside of the large-diameter steel pipe.

[0009] A serrated pile head is provided on the bottom surface of the steel pipe. The serrated pile head includes several vertical serrations, so that the serrated pile head serves as the penetration end of the large-diameter steel pipe.

[0010] The large-diameter steel pipes are connected and extended using an assembly-type structure.

[0011] At least two sets of stirring blades are provided on the bottom outer wall of the steel pipe, and each set of stirring blades includes two stirring blades symmetrically arranged on the bottom outer wall of the steel pipe.

[0012] The two adjacent sets of stirring blades along the length of the steel pipe are arranged orthogonally.

[0013] The grouting nozzle is connected to a grouting pipe, and the length of the grouting pipe is appropriately matched with the length of the large-diameter steel pipe.

[0014] The advantages of this invention are: 1) The steel pipe pile ends are not sealed, which greatly reduces the resistance of the steel pipe mixing and sinking, and can be adapted to large diameter and deep pile foundations.

[0015] 2) The use of steel-concrete composite structures with high load-bearing capacity to bear the upper load significantly reduces the cross-sectional area of ​​the core piles.

[0016] 3) Using large-diameter cement-soil to obtain the side friction resistance around the pile significantly improves the side friction resistance of the pile foundation.

[0017] 4) Enables steel pipe composite piles to be made into pile foundations with high bearing capacity and large depth.

[0018] 5) The steel pipes sink synchronously, preventing hole collapse and ensuring construction quality.

[0019] 6) It can be widely used in various large-diameter and deep pile foundation projects, and has broad application prospects. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the construction process of the present invention. Figure I ; Figure 2 This is a schematic diagram of the structure of the stirring head in this invention; Figure 3 This is a schematic diagram of the sawtooth pile head in this invention; Figure 4 This is a schematic diagram of the construction process of the present invention. Figure II ; Figure 5 This is a schematic diagram of the structure of the present invention; Figure 6 This is a schematic diagram of the construction process of the present invention. Figure III ; Figure 7 This is a schematic diagram of the construction process of the present invention. Figure IV . Detailed Implementation

[0021] The features and other related features of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments, so as to facilitate understanding by those skilled in the art: like Figure 1-7 As shown in the figure, the markings represent: 1. Cement grout pump, 2. Grouting hose, 3. Mixing head, 4. Large diameter steel pipe, 5. Grouting steel pipe, 6. Rotary power head, 7. Frame, 8. Guide frame, 9. Mixing blade, 10. Grouting nozzle, 11. Serrated pile head, 12. Soil inside steel pipe, 13. Cement soil, 14. Rotary drilling rod, 15. Concrete grouting pipe, 16. Concrete truck.

[0022] Example: Figures 1 to 7 As shown, the construction method of large-diameter steel pipe composite pile in this embodiment is used to construct a large-diameter steel pipe 4 composed of a large-diameter steel pipe 4, a filling body and a cement-soil 13, wherein the large-diameter steel pipe 4 is placed in the cement-soil 13 and the filling body is placed in the large-diameter steel pipe 4.

[0023] In this embodiment, combined with Figure 1 and Figure 2 As shown, the bottom of the large-diameter steel pipe 4 is open. A stirring blade 9, serving as a stirring head 3, is provided on the outer wall of the bottom of the large-diameter steel pipe 4. That is, in this embodiment, the stirring head 3 is located near the bottom of the outer wall of the large-diameter steel pipe 4. A slurry nozzle 10 is provided below the stirring blade 9, and the slurry nozzle 10 is opened on the pipe body of the large-diameter steel pipe 4.

[0024] Combination Figure 1 , Figure 4 , Figure 6 and Figure 7 In this embodiment, the construction process specifically includes the following steps: 1) such as Figure 1As shown, the rotary power head 6 grips the large-diameter steel pipe 4 and rotates, driving the bottom mixing blades 9 to rotate and cut the soil. At the same time, the cement slurry pump 1 injects cement slurry into the grouting nozzle 10 through the grouting hose 2 and the grouting steel pipe 5. The soil at the pile head is fully mixed with the cement slurry under the mixing of the mixing blades 9 to form cement-soil 13. Meanwhile, the frame 7 drives the large-diameter steel pipe 4 and the mixing blades 9 to sink into the soil while mixing (this process is similar to that of mixing piles). If remixing is required, the frame 7 can also drive the large-diameter steel pipe 4 and the mixing blades 9 to move up and down and reciprocate to complete the remixing.

[0025] 2) such as Figure 4 and Figure 5 As shown, when the construction of a section of large-diameter steel pipe 4 is completed, but its pile length does not reach the designed pile length, the large-diameter steel pipe 4 is extended to the next section of large-diameter steel pipe by threading or welding. At the same time, the grouting steel pipe 5 inside the large-diameter steel pipe 4 is also connected by a joint to complete the extension of the grouting pipeline. Then, the first step is repeated, and the cement soil 13 of the mixing pile on the outside is constructed by spraying grout and mixing downwards.

[0026] During this process, since the bottom of the large-diameter steel pipe 4 is set as an open structure, the soil at the pile head will enter the interior of the large-diameter steel pipe 4 through the bottom opening during its sinking process, thereby forming a soil plug, which improves the bearing capacity of the pile; after reaching the designed pile length, a composite pile foundation is formed with cement soil 13 (mixing pile) on the outer periphery of the large-diameter steel pipe 4 and soil 12 inside the steel pipe 4.

[0027] 3) When the soil plugging effect provided by the soil entering the large-diameter steel pipe 4 is insufficient to provide adequate bearing capacity, concrete needs to be poured into the large-diameter steel pipe 4. The following procedures are then performed: like Figure 6 As shown, the soil 12 inside the large-diameter steel pipe 4 is cleared by using a rotary drilling rod 14 or a circulating drilling method.

[0028] 4) After step 3), the concrete truck 16 carrying concrete pours concrete into the large-diameter steel pipe 4 through the concrete grouting pipe 15 to form a steel pipe concrete core pile, thus completing the construction of the steel pipe composite pile.

[0029] In this embodiment, a sawtooth pile head 11 is provided on the bottom surface of the large-diameter steel pipe 4. The sawtooth pile head includes several vertical sawtooths arranged along the circumference of the large-diameter steel pipe 4. Each sawtooth is used to cut the soil when the large-diameter steel pipe 4 is slid down, which further facilitates the sliding construction of the large-diameter steel pipe 4. At the same time, the sawtooths will embed into the soil to form a stable resistance surface, so that the rotational torque is more effectively converted into downward propulsion force, avoiding energy waste and further improving construction efficiency.

[0030] like Figure 2 As shown, at least two sets of mixing blades 9 are provided on the bottom outer wall of the large-diameter steel pipe 4. These mixing blades 9 can also be configured as wedge-shaped structures to facilitate cutting the soil. In this embodiment, each set of mixing blades includes two mixing blades 9 symmetrically arranged on the bottom outer wall of the large-diameter steel pipe 4. Adjacent sets of mixing blades are orthogonally arranged along the length of the steel pipe to improve the mixing effect. In specific designs, more sets of mixing blades can be arranged along the length of the bottom outer wall of the large-diameter steel pipe 4. Furthermore, more mixing blades 9 within the same set can be used and arranged symmetrically and equally divided along the circumference of the large-diameter steel pipe 4.

[0031] Although the above embodiments have described the concept and embodiments of the present invention in detail with reference to the accompanying drawings, those skilled in the art will recognize that various improvements and modifications can still be made to the present invention without departing from the scope of the claims, and therefore will not be elaborated here.

Claims

1. A construction method for large-diameter steel pipe composite piles, characterized in that: The construction method includes the following steps: An opening is provided at the bottom of a large-diameter steel pipe to form a soil inlet. A mixing blade is provided on the outer wall of the bottom of the large-diameter steel pipe, and a grouting nozzle is opened on the steel pipe body below the mixing blade. The large-diameter steel pipe is rotated and lowered while cement grout is sprayed into the soil around the large-diameter steel pipe through the grouting nozzle. The soil at the pile head is mixed with the cement grout to form cement soil. During the sinking process of the large-diameter steel pipe, the soil at the pile head enters the large-diameter steel pipe to form a soil plug, forming a composite pile foundation with a mixing pile on the outer periphery of the large-diameter steel pipe and soil inside the large-diameter steel pipe.

2. The construction method for a large-diameter steel pipe composite pile according to claim 1, characterized in that: According to the bearing capacity requirements of large-diameter steel pipe composite piles, the soil inside the large-diameter steel pipe is cleaned, and then a certain height of concrete is poured into the inside of the large-diameter steel pipe.

3. The construction method for a large-diameter steel pipe composite pile according to claim 1, characterized in that: A serrated pile head is provided on the bottom surface of the steel pipe. The serrated pile head includes several vertical serrations, so that the serrated pile head serves as the penetration end of the large-diameter steel pipe.

4. The construction method for a large-diameter steel pipe composite pile according to claim 1, characterized in that: The large-diameter steel pipes are connected and extended using an assembly-type structure.

5. The construction method for a large-diameter steel pipe composite pile according to claim 1, characterized in that: At least two sets of stirring blades are provided on the bottom outer wall of the steel pipe, and each set of stirring blades includes two stirring blades symmetrically arranged on the bottom outer wall of the steel pipe.

6. The construction method for a large-diameter steel pipe composite pile according to claim 5, characterized in that: The two adjacent sets of stirring blades along the length of the steel pipe are arranged orthogonally.

7. The construction method for a large-diameter steel pipe composite pile according to claim 1, characterized in that: The grouting nozzle is connected to a grouting pipe, and the length of the grouting pipe is appropriately matched with the length of the large-diameter steel pipe.

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