JPH05230830A - Hollow pile constructing method - Google Patents

Abstract

PURPOSE:To improve a tip bearing power of a pile, and reduce filthiness of a construction site caused by waste soil by rotating/inserting a hollow pillar in/into a soil cement pillar while forming the soil cement pillar in the ground, and discharging the waste soil by means of spiral vanes. CONSTITUTION:A single or plural number of spiral vanes 1 are arranged protrusively on the tip part outer periphery of a hollow steel pipe pile A, and an excavation bit 3 to which an expanded vane is fixed, a corotation preventive vane 4 and an agitating vane 5 are also installed on an excavation rod 2 of an excavator B. While forming a soil cement pillar in the ground, a steel pipe pile A is rotated in/inserted into the soil cement pillar. At this time, waste soil is discharged to the ground along the outer peripheral part of the steel pipe pile A by means of the spiral vanes 1. It is preferable to set an outer diameter of these spiral vanes 1 approximately equal to a diameter of the soil cement pillar, and it is also preferable to make the tips of the spiral vanes 1 come out more forward than the tip of the steel pipe pile A.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for constructing hollow prefabricated piles.

[0002]

2. Description of the Related Art In recent years,
Since it is difficult to secure a disposal site for construction surplus soil, it is required to develop a pile foundation method that produces less construction surplus soil.
A method of combining soil cement columns and ready-made piles has been invented. Construction methods for this composite pile include a pre-boring construction method in which a prefabricated pile is inserted after the soil cement column is constructed, and a middle excavation construction method in which the prefabricated pile is inserted while the soil cement column is constructed and rotated at the same time.

The above-mentioned pre-boring method has the drawbacks that the soil cement column and the ready-made pile have a large misalignment and the construction length is short. In the underground digging construction method, soil such as soil cement is discharged from the pile head through the hollow part of the ready-made pile at the time of construction, so the soil is scattered and it contaminates the site and the construction machine and causes a failure of the construction machine. However, there is a drawback in that the possibility of personal injury to field workers due to the fall of soil discharge increases.

The present invention was developed in view of the above circumstances.

[0005]

According to the present invention, one or more spiral blades are attached to the outer peripheral portion of the tip of a hollow pile to form a soil cement column in the ground, and the hollow pile is formed in the soil cement column. It is a construction method in which the soil is rotated and inserted and the soil is removed along the outer periphery of the hollow pile.

[0006]

EXAMPLE Two hollow spiral piles 1 and 1 are provided so as to project from the outer periphery of the hollow pile to be buried, especially the steel pipe pile A.
On the excavating rod 2 of the excavator B, an excavating bit 3 having a tip end expanding blade fixed, a co-rotation preventing blade 4 and a stirring blade 5 are projected. Further, a jet of a solidifying material liquid such as cement milk is provided at the tip of the excavator B, and a soil cement column is created by rotating and excavating the excavator B with an auger motor while ejecting the solidifying material liquid. Meanwhile, the steel pipe pile A is rotated in the direction opposite to that of the excavator B, and is inserted and buried in the soil cement column. The steel pipe pile A is inserted to the bottom of the excavation hole, and finally the excavator B is pulled up and collected.

The spiral blade 1 is composed of one leaf or a plurality of two or more leaves, and the outer diameter thereof is substantially the same as that of the soil cement column. The number of spiral blades 1 has a relationship with the inclination angle, but it is preferable that the number is two or more if possible. With this spiral wing 1, soil cement formed by mixing and agitating the ground and the solidifying material liquid in the excavation portion preceding the steel pipe pile A is called to the outer peripheral portion of the steel pipe pile A and is discharged to the ground by pushing it up. Let And the spiral blade 1 can improve the soil removal effect by providing intermittently or continuously in the full length of a pile. At this time, spiral wings 1
If the tip end of the steel pipe pile A projects slightly below the steel pipe pile A, the function of attracting soil cement to the outer peripheral portion of the steel pipe pile A is further improved. Further, if the outer diameter of the spiral wing 1 is larger than the outer diameter of the soil cement column, it becomes difficult to insert the steel pipe pile A,
If the diameter is smaller than the outer diameter, misalignment is likely to occur, and the integrity of the outer peripheral portion of the steel pipe pile A with the soil cement column decreases,
Tip support power is reduced.

[0008]

According to the present invention, which has the above-mentioned structure, hollow piles such as steel pipe piles are simultaneously inserted and buried while constructing soil cement columns by the medium excavation method. Since it is mainly discharged to the ground through the soil cement column around the outer periphery of the hollow pile, the soil is not discharged from the hollow pile head, and there is no contamination of the site due to scattering. Further, since the outer diameter of the spiral blade is substantially the same as the outer diameter of the soil cement column, the misalignment between the soil cement column and the hollow pile does not occur. In addition, since the strength of the soil cement column tip and the hollow pile tip are more firmly integrated by the spiral blade, the tip supporting force of the pile is greatly improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a construction process of the present invention, in which (a) and (b) show a construction sequence.

FIG. 2 is a cross-sectional view of the construction process of the present invention, in which (a) and (b) are shown in FIG.
The following construction sequence is shown.

FIG. 3 is a cross-sectional view of the construction process of the present invention, in which (a) and (b) are shown in FIG.
The following construction sequence is shown.

[Explanation of symbols]

A ... Steel pipe pile, B ... Excavator, C ... Sediment, D ... Consolidation 1 ... Spiral blade, 2 ... Excavation rod, 3 ... Excavation bit,
4 ... co-rotation prevention blade, 5 ... stirring blade.

Claims (4)

[Claims] 1. A hollow cement pile is attached to the tip outer peripheral portion of a hollow pile or a plurality of spiral blades to form a soil cement column in the ground, and the hollow pile is rotationally inserted into the soil cement column. The method of constructing hollow piles. 2. The method for constructing a hollow pile according to claim 1, wherein the soil is discharged to the ground along the outer periphery of the hollow pile by the spiral blade. 3. The method for constructing a hollow pile according to claim 1, wherein the outer diameter of the spiral blade is substantially the same as the diameter of the soil cement column. 4. The method for constructing a hollow pile according to claim 1, wherein the tip of the spiral blade is projected before the tip of the hollow pile.