JPH05340180A - Excavator for cast-in-place pile and cast-in-place pile method - Google Patents

Abstract

PURPOSE:To make it possible to cut and crush obstacles to excavate a pile-hole efficiently even if there are obstacles in the ground. CONSTITUTION:A stone-mill-shaped cutting panel 6 is provided to the lower end of a casing 2 rotating around its peripheral surface. The cutting panel 6 forms the bottom 6a in the shape of a center high cone and, at the same time, a mucking hole 6b passing through the cutting panel 6 is provided to the center thereof. A large number of spiral projection threads 6c are provided to the conical surface 6a, and a large number of bits 7 are arranged to a part of the projection threads 6c and the peripheral surface 6d of the cutting panel 6. A screw conveyer 8 is connected to the mucking hole 6b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard obstacle such as bedrock, existing concrete piles or concrete buildings when excavating the ground to form a cast-in-place pile in the ground. The present invention relates to an excavation device for cast-in-place piles used for rotary excavation and removal of these obstacles, and a cast-in-place pile construction method using the device.

[0002]

2. Description of the Related Art As one of the cast-in-place pile construction methods, there is an earth drill construction method in which the ground is excavated by a rotating bucket.
When constructing this method, if there are rocks or hard obstacles such as prefabricated concrete piles or concrete buildings in the ground, excavation by the rotating bucket described above becomes impossible. The excavation was stopped and the obstacles in the ground were removed by another conventional obstacle removing means (for example, crushing means by impact).

Recently, a method of excavating a hole for a cast-in-place pile by attaching an ultra-hard excavating bit to the lower end of a casing used in the all-casing method and pushing it into the ground while making a full turn. Has also been done.

[0004]

However, as described above, in order to remove obstacles during the earth drilling method, it is necessary to temporarily remove the excavating device using the rotating bucket, so that it is not possible to perform consistent work. Therefore, there is a problem that it takes a lot of trouble and is troublesome and that the construction period is long.

Further, in the method of turning the casing around the entire circumference, when the obstacle in the ground is large, the cut obstacle has a large round bar shape, which makes it difficult to take it out to the outside. It was

[0006]

In order to solve the above-mentioned problems, according to the present invention, a stone mill-like cutting machine is provided at the lower end of a casing that rotates all around, and the lower surface of the cutting machine is formed into a medium-high cone shape. With the provision of a through hole that penetrates the cutting machine at the center thereof, a large number of spiral projections are provided on the conical surface, and a large number of bits are arranged on these projections and the outer peripheral portion of the cutting machine. The excavation device for cast-in-place piles is configured by connecting a screw conveyor to the slide-out hole.

Further, as the cast-in-place pile construction method, the above-mentioned excavator for cast-in-place pile is rotated all the way around and pushed into the ground to crush underground obstacles such as earth and sand and boulders, and the shavings are removed. While pushing up from the central slide hole, it is discharged to the outside by the screw conveyor, and after the excavation is completed, the bentonite liquid is filled into the excavation hole and the excavation device is pulled out while building the rebar while protecting the hole wall. To place.

[0008]

In the present invention, since the excavation device for cast-in-place piles is constructed as described above, when a hard obstacle is encountered in the ground during excavation, a stone-milling cutting machine provided at the lower end of the casing is used. A large number of bits on the underside cut the obstacles and break them into small pieces.

Then, the crushed small pieces and the excavated earth and sand are gathered from the outer peripheral portion to the central portion by the spiral protrusions on the lower surface of the cutting machine, and are pushed into the slide holes at the central portion, and are externally driven by the screw conveyor. Is discharged to.

As described above, according to the present invention, even if there is a hard obstacle in the ground, it is possible to efficiently excavate a pile hole by the continuous operation by the excavation device of the present invention. Therefore, according to the present invention, this kind of work is simplified and the efficiency is improved, and the construction period can be shortened.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In the figure, 1 is the ground, 2 is a casing to be pushed into the ground,
Reference numeral 3 is a device for pushing the casing 2 into the ground while rotating the casing 2.

In this embodiment, the lower end portion 2a of the casing 2 and the upper edge portion 4a of the cylinder 4 are formed in a cage-like shape and are fitted together, and a pin 5 penetrating them is used to connect them. At the bottom of this cylinder 4 is a milling machine 6
To provide.

As shown in detail in FIG. 2, the cutting machine 6 has a lower surface 6a formed in a medium-height conical shape, and a slit hole 6b penetrating the cutting machine 6 is provided at the center thereof so that the conical surface 6a is formed. A large number of spiral ridges 6c are provided, and a large number of super-hard bits 7 are arranged in a part of these ridges 6c and the outer peripheral portion 6d of the cutting machine 6, and further above the slide-out hole 6b. The screw conveyor 8 is connected and provided.

A projecting piece 6e projecting in the shape of a triangular plate is provided in the slide-out hole 6b in the central portion for attaching the bit 7 for cutting the central portion, and is shown in FIGS. 1 and 2 (b). The holes 6f are bentonite liquid injection holes. Further, 8a is an outer cylinder of the screw conveyor 8, 8b is a screw rotating in the outer cylinder 8a, and 9 is a driving motor thereof.

Next, referring to FIG. 3, the cast-in-place pile construction method of the present invention will be described. First, as shown in FIG. 3 (a), the casing 2 of the above-mentioned excavator for cast-in-place pile is indicated by an arrow A (see FIG. 2 (b)), while rotating all around in the direction shown in Fig. 2 (b) and pushing it into the ground as shown by arrow B, the underground obstacle 10 such as concrete pile is cut and crushed by the bit 7, and the shavings and earth and sand are removed. Is pushed up from the central slide-out hole 6b by the action of the spiral protrusion 6c, and is discharged to the outside as indicated by an arrow C by the screw conveyor 8 driven by the motor 9.

Next, as shown in FIG. 3 (b), after the excavation, the bentonite liquid is guided from the outside into the casing 2 as shown by an arrow D, and then from the hole 6f of the cutting machine 6 as shown by an arrow E. Then, as shown in FIG. 3 (c), the excavator is pulled out as shown in FIG. As shown in Fig. 3 (d), after the rebar 12 has been installed,
As shown by arrow G, green concrete is placed in the pile hole through a tremie pipe (not shown) or the like as shown by arrow G.

In the present invention, since the excavation device for cast-in-place piles is constructed as described above, if a hard obstacle is encountered in the ground during excavation, a stone mill-like cutting machine provided at the lower end of the casing 2 A large number of bits 7 provided on the lower surface of 6 allow the obstacle to be cut and crushed into small pieces.

The crushed small pieces and the excavated earth and sand are gathered from the outer peripheral portion to the central portion by the spiral projections 6c on the lower surface 6a of the cutting machine 6 and are pushed into the slip-out holes 6b in the central portion. , Is discharged to the outside by the screw conveyor 8.

[0019]

As described above, according to the present invention, even if there is a hard obstacle in the ground, it is possible to efficiently excavate a pile hole by the continuous work by the excavation device of the present invention. Therefore, according to the present invention, an excellent effect that this type of work is simplified and the efficiency is improved and the construction period can be shortened is obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the device of the present invention.

[FIG. 2] (a) is an elevation view of the cutting machine of FIG. 1, (b)
Is a bottom view thereof, and (c) is a sectional view taken along line CC of (a).

3 (a) to (d) are process explanatory diagrams of the method of the present invention.

[Explanation of symbols]

 1 Ground 2 Casing 3 Casing Swivel Pushing Device 4 Cylindrical 5 Pin 6 Cutting Machine 6a Lower Surface (Conical Surface) 6b Slide Out Hole 6c Spiral Ridge 6d Outer Part 6e Projection Piece 6f Injection Hole 7 Bit 8 Screw Conveyor 9 Drive Motor 10 Underground obstacles 11 Bentonite liquid 12 Rebar

Claims (2)

[Claims] 1. A stone mill-like cutting machine is provided at the lower end of a casing that rotates all around, and the lower surface of this cutting machine is formed into a conical shape with a middle height, and a slit hole is formed at the center thereof to penetrate the cutting machine. A large number of spiral protrusions are provided on the conical surface, a large number of bits are arranged on the protrusions and the outer peripheral portion of the cutting machine, and a screw conveyor is connected to the slide-out hole. Drilling equipment for piles. 2. The in-ground excavator for cast-in-place piles according to claim 1 is pushed into the ground while rotating all around, thereby crushing underground obstacles such as earth and sand and boulders, and scraping the shavings at the center. While pushing up from the exit hole and discharging to the outside by the screw conveyor, after the excavation is completed, the bentonite liquid is filled into the excavation hole to pull out the excavation device while protecting the hole wall, build up the reinforcing bar, and then place ready-mixed concrete. Cast-in-place pile construction method characterized by: