Construction method of rigid-flexible composite pile foundation

Abstract

The invention relates to a construction method of a rigid-flexible composite pile foundation, which is characterized in that a stirring head is mounted at the lower part of a steel pipe, the stirring head comprises a steel pipe section, a group of stirring blades are arranged outside the steel pipe, a conical part is arranged at the bottom of the steel pipe section, another group of stirring blades are arranged on the conical part, and a grouting pipe is arranged inside the steel pipe section; the grouting pipe comprises a vertical section which is vertically arranged in the steel pipe section and a horizontal section which is arranged above the group of stirring blades of the conical part, and the vertical section is communicated with the horizontal section; the steel pipe is driven to rotate through an upper power device, grouting is carried out on the horizontal section through the vertical section of the grouting pipe, and grouting is carried out while rotary stirring is carried out, so that a pile periphery stirring pile is formed; a cementing material is poured into the steel pipe to form a rigid core pile, the rigid core pile is located in the stirring pile around the pile, and the rigid core pile and the stirring pile are combined to form the rigid-flexible composite pile foundation. The composite pile has the advantages that the torsion resistance of the mixing pile is greatly improved, the drilling capacity of the mixing pile is greatly enhanced, and the bearing capacity and the deformation control capacity of the composite pile are greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of pile foundations, and in particular to a construction method of a rigid-flexible composite pile foundation. Background Art

[0002] The existing mixing pile mixing head is connected with the grouting pipe, the grouting pipe has a small diameter, weak torque resistance and limited drilling capacity, and the formed mixing pile is a flexible pile with limited bearing capacity. Summary of the invention

[0003] The purpose of the present invention is to provide a construction method of a rigid-flexible composite pile foundation based on the above-mentioned deficiencies in the prior art, in which the grouting pipe and the mixing pile drive shaft are separately arranged, the outer large-diameter steel pipe is used as the mixing drive shaft, the large-diameter steel pipe head is the mixing pile head, and the grouting pipe is placed inside the steel pipe, so that the torque of the mixing pile is greatly increased, thereby greatly increasing the drilling capacity of the mixing pile.

[0004] The purpose of the present invention is achieved by the following technical solutions: A construction method for a rigid-flexible composite pile foundation, characterized in that the construction method comprises the following steps: A stirring head is installed at the lower part of the steel pipe, the stirring head comprises a steel pipe section, the top of the steel pipe section is the connecting part of the steel pipe, a group of stirring blades are arranged outside the steel pipe, a conical part is arranged at the bottom of the steel pipe section, another group of stirring blades are arranged on the conical part, a grouting pipe is arranged inside the steel pipe section, the grouting pipe comprises a vertical section vertically arranged in the steel pipe section and a horizontal section arranged above the group of stirring blades in the conical part, the vertical section is connected with the horizontal section; The steel pipe is driven to rotate by an upper power device, and grouting is injected from the vertical section of the grouting pipe to the horizontal section, while rotating and stirring and grouting, to form a pile perimeter mixing pile; A cementing material is poured into the steel pipe to form a rigid core pile. The rigid core pile is located inside the mixing pile around the pile. The combination of the two constitutes a rigid-flexible composite pile foundation.

[0005] A grouting pipe connected to the vertical section of the grouting pipe is arranged inside the steel pipe.

[0006] The vertical section and the horizontal section of the grouting pipe are connected via a joint.

[0007] The horizontal extension length of the horizontal section does not exceed the corresponding extension length of the stirring blade.

[0008] The two groups of stirring blades are arranged perpendicularly to each other.

[0009] The advantages of the present invention are: the mixing blades are on the external steel pipe wall and the grouting pipe is inside the steel pipe, which greatly improves the torsion resistance of the mixing pile and greatly enhances the drilling ability of the mixing pile. At the same time, the steel pipe and the mixing head are left in the composite pile as a core pile, 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 The construction process of the present invention Figure I ; Figure 2 The construction process of the present invention Figure II ; Figure 3 The construction process of the present invention Figure III ; Figure 4 It is a schematic diagram of the structure after the construction of the present invention is completed. DETAILED DESCRIPTION

[0011] The features of the present invention and other related features are further described in detail below through embodiments in conjunction with the accompanying drawings to facilitate understanding by those skilled in the art: like Figure 1-4 As shown, the numbers 1-8 in the figure respectively represent: steel pipe section 1, grouting pipe 2, mixing blade 3, transverse grouting pipe 4, steel pipe joint 5, steel pipe 6, mixing pile cement soil 7, and bonding material 8.

[0012] Example: Combination Figures 1 to 3 As shown, the stirring head body for improving the drilling ability in this embodiment includes a steel pipe section 1, and 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 stirring head is installed to the bottom position of the steel pipe 6.

[0013] Two groups of stirring blades 3 are arranged on the periphery of the steel pipe section 1, one group of stirring blades 3 is directly arranged on the outer wall of the steel pipe section 1, and the other group of stirring blades 3 is arranged on the conical portion arranged at the bottom of the steel pipe section 1; the two groups of stirring blades 3 are arranged vertically to improve the stirring effect, especially the stirring uniformity. When the steel pipe section 1 is driven to rotate, the stirring blades 3 cut and stir the soil. In this embodiment, the conical portion extends from the bottom of the steel pipe section 1, which facilitates the soil penetration of the steel pipe section 1.

[0014] A grouting pipe is arranged inside the steel pipe section 1, and the grouting pipe includes two parts, one of which is a grouting pipe 2 arranged vertically inside the steel pipe section 1, and the other is a transverse grouting pipe 4 extending horizontally from the conical part at the bottom of the steel pipe section 1, and the transverse grouting pipe 4 is connected with the grouting pipe 2. When the steel pipe section 1 is connected with the steel pipe 6 through the steel pipe joint 5, the grouting pipe 2 is also connected with the grouting pipe arranged inside the steel pipe 6 and is connected, so that the grouting is smoothly carried out, and at the same time, the torque of the mixing pile is greatly increased, and the drilling capacity of the mixing pile is greatly increased.

[0015] In this embodiment, the transverse grouting pipe 4 is arranged on the stirring blades 3 located at the tapered portion, and the horizontal extension length of the transverse grouting pipe 4 does not exceed the extension length of the group of stirring blades 3, so that during the drilling process, the group of stirring blades 3 can play a certain protective role for the transverse grouting pipe 4, that is, wherever the transverse grouting pipe 4 goes, the soil has been cut and stirred, thereby ensuring that the transverse grouting pipe 4 is not damaged by the pressure of the harder soil.

[0016] During construction, this embodiment includes the following construction steps: 1) The mixing head is manufactured and connected to the steel pipe 6 via the steel pipe joint 5, and the grouting pipe 2 is connected to the grouting pipe arranged in the steel pipe 6.

[0017] 2) The upper power device drives the steel pipe 6 to rotate, and the steel pipe 6 drives the mixing head to rotate synchronously through the steel pipe joint 5. The mixing blades 3 on the outer periphery of the steel pipe 6 cut and mix the soil, and grouting is injected into the horizontal grouting pipe 4 through the grouting pipe 2 in the steel pipe, while rotating and mixing and grouting, to form the mixing pile cement soil 7 of the pile periphery mixing pile.

[0018] 3) Concrete, mortar, cement paste or other cementing 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 constitute a rigid-flexible composite pile foundation.

[0019] After completion, the mixing head remains in the cement soil 7 of the mixing pile, playing a role in strengthening the bottom of the pile foundation, especially the mixing blades as transverse reinforcement, which can improve the bearing capacity of the composite pile foundation.

[0020] Although the above embodiments have described in detail the concepts and embodiments of the present invention with reference to the accompanying drawings, ordinary technicians in this field can recognize that various improvements and changes can still be made to the present invention without departing from the scope of the claims, so they are not described one by one here.

Claims

1. A construction method for a rigid-flexible composite pile foundation, characterized in that: The construction method comprises the following steps: A mixing head is installed at the lower part of the steel pipe, the mixing head comprises a steel pipe section, the top of the steel pipe section is the connecting part of the steel pipe, a group of mixing blades are arranged outside the steel pipe section, a tapered part is arranged at the bottom of the steel pipe section, another group of mixing blades are arranged on the tapered part, a grouting pipe is arranged inside the steel pipe section, the grouting pipe comprises a vertical section vertically arranged in the steel pipe section and a horizontal section arranged above the group of mixing blades in the tapered part, the vertical section is connected with the horizontal section; The steel pipe is driven to rotate by an upper power device, and grouting is injected from the vertical section of the grouting pipe to the horizontal section, while rotating and stirring and grouting, to form a pile perimeter mixing pile; A cementing material is poured into the steel pipe to form a rigid core pile. The rigid core pile is located inside the mixing pile around the pile. The combination of the two constitutes 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 connected to the vertical section of the grouting pipe is arranged inside the steel pipe.

3. The construction method of a rigid-flexible composite pile foundation according to claim 1, characterized in that: The vertical section and the horizontal section of the grouting pipe are connected via 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 section does not exceed the corresponding extension length of the stirring blade.

5. The construction method of a rigid-flexible composite pile foundation according to claim 1, characterized in that: The two groups of stirring blades are arranged perpendicularly to each other.

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