Construction method for rigid-flexible composite pile foundation
By separating the grouting pipe from the drive shaft of the mixing pile and installing the grouting pipe inside the steel pipe, a rigid-flexible composite pile foundation is formed, which solves the problem of weak torque resistance of mixing piles in the existing technology and realizes efficient drilling and improved bearing capacity of mixing piles.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- CHINA RAILWAY SHANGHAI DESIGN INST GRP CO LTD
- Filing Date
- 2025-10-29
- Publication Date
- 2026-06-18
AI Technical Summary
The existing grouting pipes for mixing piles have small diameters, weak torque resistance, and limited drilling capacity, resulting in insufficient bearing capacity.
The grouting pipe is set separately from the mixing pile drive shaft. A large-diameter steel pipe is used as the mixing drive shaft, and the grouting pipe is installed inside the steel pipe. The rigid-flexible composite pile foundation is formed by rotation mixing and grouting. The steel pipe and mixing blades are used to improve the torsional resistance and drilling capacity of the mixing pile.
It significantly improves the drilling capacity and bearing capacity of mixing piles, and enhances the overall rigidity and deformation control of composite piles.
Smart Images
Figure CN2025130757_18062026_PF_FP_ABST
Abstract
Description
A construction method for rigid-flexible composite pile foundations Technical Field
[0001] This invention relates to the field of pile foundation technology, and specifically to a construction method for rigid-flexible composite pile foundations. Background Technology
[0002] The existing mixing pile mixing head is connected to the grouting pipe. The grouting pipe has a small diameter, weak torque resistance, and limited drilling capacity. The resulting mixing pile is a flexible pile with limited bearing capacity. Summary of the Invention
[0003] The purpose of this invention is to address the shortcomings of the prior art by providing a construction method for rigid-flexible composite pile foundations. This method separates the grouting pipe from the mixing pile drive shaft, uses a large-diameter steel pipe as the mixing drive shaft, and the large-diameter steel pipe head as the mixing pile head. The grouting pipe is placed inside the steel pipe, which significantly increases the torque of the mixing pile and greatly enhances its drilling capacity.
[0004] The objective of this invention is achieved through the following technical solutions:
[0005] A construction method for a rigid-flexible composite pile foundation, characterized by the following steps:
[0006] A stirring head is installed at the lower part of a steel pipe. The stirring head includes a steel pipe section, the top of which is a connecting part of the steel pipe. A set of stirring blades is provided on the outside of the steel pipe. A conical part is provided at the bottom of the steel pipe section, and another set of stirring blades is provided on the conical part. A grouting pipe is provided inside the steel pipe section. The grouting pipe includes a vertical section arranged vertically inside the steel pipe section and a horizontal section arranged above the set of stirring blades on the conical part. The vertical section and the horizontal section are connected.
[0007] The steel pipe is rotated by the upper power device, and grout is injected into the horizontal section through the vertical section of the grouting pipe. The grouting is carried out while rotating and stirring, forming a pile-peripheral mixing pile.
[0008] A rigid core pile is formed by injecting cementing material into the steel pipe. The rigid core pile is located within the mixing pile around the pile, and the two together constitute a rigid-flexible composite pile foundation.
[0009] A grouting pipe is arranged inside the steel pipe and connected to the vertical section of the grouting pipe.
[0010] The vertical section and the horizontal section of the grouting pipe are connected by a joint.
[0011] The horizontal extension length of the horizontal segment does not exceed the extension length of the corresponding stirring blade.
[0012] The two sets of stirring blades are arranged perpendicularly to each other.
[0013] The advantages of this invention are: by using mixing blades on the outer steel pipe wall and grouting pipe inside the steel pipe, the torsional resistance of the mixing pile is greatly improved, and the drilling ability of the mixing pile is greatly enhanced. At the same time, the steel pipe and mixing head remain inside the composite pile as core piles, which greatly improves the bearing capacity and deformation control ability of the composite pile. It can be widely used in various foundation treatment projects and has broad application prospects. Attached Figure Description
[0014] Figure 1 is a construction process diagram of the present invention (I);
[0015] Figure 2 is a construction process diagram of the present invention (II);
[0016] Figure 3 is a construction process diagram of the present invention (III);
[0017] Figure 4 is a schematic diagram of the structure after the construction of the present invention is completed. Detailed Implementation
[0018] 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:
[0019] As shown in Figure 1-4, the numbers 1-8 in the figure represent: 1. Steel pipe section, 2. Grouting pipe, 3. Mixing blade, 4. Horizontal grouting pipe, 5. Steel pipe joint, 6. Steel pipe, 7. Mixing pile cement soil, and 8. Cementing material.
[0020] Example: As shown in Figures 1 to 3, the main body of the mixing head for improving drilling capability in this example includes a steel pipe section 1. The upper part of the steel pipe section 1 has a steel pipe joint 5. The steel pipe section 1 can be installed to the bottom of the steel pipe 6 through the steel pipe joint 5, that is, the mixing head is installed at the bottom position of the steel pipe 6.
[0021] Two sets of mixing blades 3 are arranged around the periphery of the steel pipe section 1. One set of mixing blades 3 is directly mounted on the outer wall of the steel pipe section 1, while the other set is mounted on the conical section at the bottom of the steel pipe section 1. The two sets of mixing blades 3 are arranged perpendicularly to improve the mixing effect, especially the uniformity of mixing. When the steel pipe section 1 rotates under drive, the mixing blades 3 cut and mix the soil. In this embodiment, the conical section extends to the bottom of the steel pipe section 1, which facilitates the penetration of soil into the steel pipe section 1.
[0022] A grouting pipe is installed inside the steel pipe section 1. This grouting pipe consists of two parts: a vertically installed grouting pipe 2 inside the steel pipe section 1, and a horizontally extending grouting pipe 4 extending laterally from the tapered part at the bottom of the steel pipe section 1. The horizontal grouting pipe 4 is connected to the grouting pipe 2. When the steel pipe section 1 is connected to the steel pipe 6 through the steel pipe joint 5, the grouting pipe 2 is also connected to the grouting pipe arranged inside the steel pipe 6, thus enabling smooth grouting and significantly increasing the torque of the mixing pile, thereby greatly increasing the drilling capacity of the mixing pile.
[0023] In this embodiment, the transverse grouting pipe 4 is set on the mixing blades 3 located at the conical part, and the horizontal extension length of the transverse grouting pipe 4 does not exceed the extension length of the mixing blades 3. Thus, during the drilling process, the mixing blades 3 can play a certain protective role for the transverse grouting pipe 4. That is, wherever the transverse grouting pipe 4 goes, it is all soil that has been cut and mixed. Therefore, it can be ensured that the transverse grouting pipe 4 is not damaged by the pressure of harder soil.
[0024] This embodiment includes the following construction steps during construction:
[0025] 1) The mixing head is manufactured and connected to the steel pipe 6 through the steel pipe joint 5. At the same time, the grouting pipe 2 is connected to the grouting pipe arranged inside the steel pipe 6.
[0026] 2) The upper power device drives the steel pipe 6 to rotate. The steel pipe 6 drives the mixing head to rotate synchronously through the steel pipe joint 5. The mixing blades 3 on the outside of the steel pipe 6 cut and mix the soil. Grout is injected into the transverse grouting pipe 4 through the grouting pipe 2 inside the steel pipe. While rotating and mixing, grout is injected to form the cement-soil mixture 7 of the pile perimeter mixing pile.
[0027] 3) Concrete, mortar, cement grout and other binding materials 8 are poured into the steel pipe 6 to form a rigid core pile. The rigid core pile and the mixing pile with the outer flexible pile form a rigid-flexible composite pile foundation.
[0028] After completion, the mixing head remains in the cement-soil mixture 7 of the mixing pile, which serves to strengthen the bottom of the pile foundation. In particular, the mixing blades act as lateral reinforcement, which can improve the bearing capacity of the composite pile foundation.
[0029] 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 a rigid-flexible composite pile foundation, characterized in that: The construction method includes the following steps: A stirring head is installed at the lower part of a steel pipe. The stirring head includes a steel pipe section, the top of which is a connecting part of the steel pipe. A set of stirring blades is provided on the outside of the steel pipe section, and a conical part is provided at the bottom of the steel pipe section. Another set of stirring blades is provided on the conical part. A grouting pipe is provided inside the steel pipe section. The grouting pipe includes a vertical section arranged vertically inside the steel pipe section and a horizontal section arranged above the set of stirring blades on the conical part. The vertical section and the horizontal section are connected. The steel pipe is rotated by the upper power device, and grout is injected into the horizontal section through the vertical section of the grouting pipe. The grouting is carried out while rotating and stirring, forming a pile-peripheral mixing pile. A rigid core pile is formed by injecting cementing material into the steel pipe. The rigid core pile is located within the mixing pile around the pile, and the two together constitute a rigid-flexible composite pile foundation.
2. The construction method of a rigid-flexible composite pile foundation according to claim 1, characterized in that: A grouting pipe is arranged inside the steel pipe and connected to the vertical section of the grouting pipe.
3. The construction method of a steel pipe composite pile foundation according to claim 1, characterized in that: The vertical section and the horizontal section of the grouting pipe are connected by a joint.
4. The construction method of a rigid-flexible composite pile foundation according to claim 1, characterized in that: The horizontal extension length of the horizontal segment does not exceed the extension length of the corresponding stirring blade.
5. The construction method of a rigid-flexible composite pile foundation according to claim 1, characterized in that: The two sets of stirring blades are arranged perpendicularly to each other.