JPS62280413A - Formation work of expanded plastic column under ground - Google Patents

Abstract

PURPOSE:To form an expanded plastic column under the ground by a method in which while a casing is pulled out, an expandible plastic material is extruded from the shaft of an earth auger. CONSTITUTION:While pulling out a casing 1 penetrated to a given depth into the ground, an expandible plastic material is extruded into a space surrounded by the casing 1 by an expandible plastic material extrusion mechanism in the shaft 5 of an earth auger 2 to form expanded plastic columns in order. The expanded plastic columns can thus be very simply formed under the ground.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Technical Field to which the Invention Pertains) The present invention relates to a construction method for constructing columnar bodies made of foamed plastic underground.

(Problems to be solved by the invention and its characteristics) In recent years, various techniques for using foamed plastics in civil engineering structures have been developed, but a technique for efficiently creating columnar bodies made of foamed plastics underground is still unknown.

The present invention has been made in view of the above-mentioned circumstances, and its structural features are as described in the claims.

According to the present invention, columnar bodies made of foamed plastic are constructed in the ground in a state directly surrounded by the ground soil. Underground ice walls can be easily constructed.

(Description of the Invention with Drawings) An embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 denotes a relatively large-diameter casing, the lower end of which is open.

The earth auger 2 is inserted into the casing 1, and the earth and sand at the tip of the casing 1 are excavated with the pit 3 at the tip, and the casing 1 is penetrated into the ground while discharging this excavated earth to the ground with the screw 4. (Figure 1 A). At this time, when the casing 1 is rotated (in the case shown, it is rotated in the opposite direction to the rotation direction of the earth auger 2)
, friction on the outer periphery of the casing 1 is removed, making penetration easier.

When the lower end of the casing 1 reaches a predetermined depth underground, the penetration should be stopped (as shown in Figure 1), and while pulling up the casing 1 and the earth auger 2, the shaft 5 of the earth auger 2 will be lowered as described below. The foamed plastic extrusion mechanism incorporated in the casing 1 is activated to sequentially form foamed plastic bodies 6 at the extrusion mark of the casing 1 (c) in Fig. 1, and this continues to form a foamed plastic columnar body 7 extending to the ground surface.
(2 in Figure 1) 0 When forming the foamed plastic body 6, the lower end of the earth auger 2 is pulled into the casing 1 by a slight height as shown in the figure, and the lower end of the earth auger 2 is pushed out. It is preferable that the foamed plastic is protected by the casing 1 until most of the foaming process is completed.

Next, the foamed plastic extrusion mechanism built into the shaft 5 will be explained. The shaft 5 has a cylindrical shape, and a screw 9 for extruding foamed plastic is installed in the lower part of the shaft 8 which is rotatably provided in the inner space of the shaft 5. , a screw 10 for feeding material (such as beads of thermoplastic synthetic resin with or without absorbing or adsorbing a blowing agent) is attached to the upper part thereof.

An inner cylinder 11 is provided on the outside of the screw 9.
A heating fluid such as hot water or steam is circulated in the annular space 12 outside the .

A foaming agent supply pipe 13 is provided within the shaft 8, and the foaming agent is discharged into the inner cylinder [1 as required.

The material sent from above enters the inner cylinder 11, is heated from the outside, and is extruded from the lower end of the inner cylinder 11 without foaming.

Of course, the present invention is not limited to the above embodiments. For example, the casing may be penetrated into the ground with the lower end closed with a lid, and the foamed plastic may be formed using a dedicated foamed plastic extruder. It doesn't matter if you do it.

(Effects of the Invention) Since the present invention is as described above, it is possible to create columnar bodies of foamed plastic underground very easily and efficiently, and as a result, the scope of use of foamed plastic in civil engineering is expanded. be able to.

[Brief explanation of the drawing]

The drawings are explanatory views of one embodiment of the present invention, in which Fig. 1 is a process diagram and Fig. 2 is a sectional view of an earth auger incorporating a foamed plastic extrusion mechanism. 1...Casing, 2...Earth Auger,...Song.

Claims (1)

[Claims] A foamed plastic columnar body characterized in that, while pulling out the casing that has penetrated into the ground to a predetermined depth, a foamed plastic extruder inserted into the casing sequentially forms the foamed plastic body in the space surrounded by the casing. Underground construction method.