JPH03129009A - Foundation improving method - Google Patents

Abstract

PURPOSE:To obtain a uniformly solidified body by rotating a drilling rod incorporated with agitating blades and a casing incorporated with pulverizing blades, which are rotatably coupled with each other, in opposite directions so as to agitate and mix excavated soil and a solidifying material. CONSTITUTION:On the outside of a drilling rode 1 from which agitating blades 4 are projected above a drilling bit 3 at the forward end of the rod, a cylindrical casing 2 from which pulverizing blades 5 which are laid alternately with the agitating blades 4 is connected to the drilling rod 1, rotatably in opposite directions. Further, the agitating blades 4 and the pulverizing blades 5 are advanced in the foundation while they are rotated in the opposite directions. After drilling is performed by a predetermined depth, a solidifying material is discharged from the forward end of the drilling rod 1 while the rod 1 and the casing 2 are rotated in directions reverse to that during drilling, and accordingly, excavated sediment is further pulverized by the blades 4, 5 while the pulverized sediment and the solidifying material are agitated and mixed. With this arrangement, it is possible to obtain a uniform mixing condition.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a ground improvement method for constructing a solid body by mixing excavated soil and a solidification material.

(Problem to be solved by the invention) The ground is excavated to a target depth, the soil and the solidification material injected from the excavation rod are stirred, and the two are mixed to create a solidified structure such as a pile in the ground. Conventionally, when the rod rotates in the forward direction, excavation is carried out using a drilling bit at the tip of the rod, and when the rod rotates in the reverse direction, stirring and mixing are carried out using stirring blades that protrude laterally at a distance in the axial direction of the rod. , but in this method lI! ! When the excavated soil is mixed with the solidified material by the stirring blade after the excavation of the disk is completed, the excavated soil forms a lump along a certain length in the axial direction and adheres around the stirring blade, and as it rotates with the stirring blade, a relatively large lump of soil is formed. This may occur.

If the soil clods generated during excavation are mixed with the solidification material during stirring, the resulting consolidated body will be heterogeneous and the compressive strength of the consolidated body may decrease, so this soil clod should be avoided as much as possible. is always a construction issue.

This invention was made by paying attention to the deafening sound of soil clods that tends to occur during excavation, and aims to propose a new method that can crush soil and create a homogeneous solid body.

(Means for Solving the Problems) In the present invention, a cylindrical drilling rod is provided with crushing blades alternately protruding from the 5 stirring positions on the outside of a drilling rod having a stirring blade protruding above the excavation bit at the tip. The lunar casing is electrically connected to the excavation rod so that it can rotate freely in reverse, and the two casings of the excavation rod are rotated in opposite directions during excavation and mixing with the solidification material, and the excavated soil is excavated while being cut by the stirring blade and the crushing blade. By performing the mixing, the excavated soil becomes a lump and lands on the stirring blade and rotates together with the excavation rod, thereby preventing the formation of sloppy soil clods and reliably creating a homogeneous compaction.

Excavation is carried out by crushing the excavated soil with stirring blades and crushing blades, and after reaching a predetermined depth, the drilling rod and casing are rotated in the opposite direction to the digging direction while discharging solidified material from the tip of the drilling loft. The excavated soil is further crushed by the stirring blade and the crushing blade, and at the same time, the crushed earth and sand and the solidification material are stirred and mixed to form a solid body.

(Example) The present invention will be explained below based on the drawings showing one embodiment.

This invention has a drilling rod 1 as shown in Fig. 1-1, II.
and a cylindrical casing 2, which is disposed outside of the casing over its entire length and is rotatably connected to the casing 2, are rotated in opposite directions during excavation and mixing with the solidification material, thereby crushing the earth and sand into appropriate sizes. This is a method to create a solid body.

The drilling rod 1 and the casing 2 are rotatably connected to each other by a speed reducer.

As shown in the figure, stirring blades 4 for mixing excavated soil and solidification material are protruded above the drilling bit 3 at the tip of the drilling rod 1, while on the inner peripheral surface of the casing 2, the stirring blades 4 are used to mix soil and solidification material during excavation. A crushing blade 5 that crushes the material together with the stirring blade 4 and supplements the stirring by the stirring blade 4 during mixing is provided protruding toward the center at a different level from the stirring blade 4 of the drilling rod 1.

Figure 2 shows a modification of Figure 1, in which the drilling rod I
This is a case where a casing 2 whose cross section expands only in the lower part and a crushing blade 5 protruding from this expanded portion is connected to the drilling rod 1.

The crusher H5 is screwed through the casing 2 from the outside or inside, and is attached by tightening a nut or the like.

The outer diameter of the casing 2 is smaller than the width of the drilling bit 3 so that it does not impinge on the drilling hole and rotates without resistance.

Drilling is performed by rotating the drilling rod 1 in the forward direction and simultaneously rotating the casing 2 in the reverse direction, digging with the drilling bit 3, and cutting the excavated earth and sand with the stirring blades 4 and the crushing blades 5. At this time, the earth and sand will be cut to a size smaller than at least the distance between the stirring blade 4 and the crusher M5. Also, during excavation, the excavated soil is pushed upwards relative to the excavation rod 1,
Depending on the stirring blade 4) The stirring blade 4 is sloped to promote crushing.

When the drilling bit 3 reaches a predetermined depth, as shown in FIG. 2, while discharging solidified material from the tip of the drilling rod 1, this and the casing 2 are rotated in the opposite direction to the drilling direction, and the stirring blade 4 and the crushing material H5 are used to rotate the solidified material from the tip of the drilling rod 1. While pulverizing the earth and sand even more finely, the earth and sand and the solidification material are stirred and combined.

At this time, due to the inclination of the stirring blades 4, the rise thereof is suppressed, contrary to the case of forward rotation, and the earth and sand and the solidified material are homogenized in the axial direction.

The solidifying material is a slurry such as fill cement, mortar, or cement milk, and is arbitrarily prepared in the plant depending on the ground conditions.

The drilling rod 1 discharges this solidified material and mixes it with earth and sand.
It may be carried out at the time of forward rotation of the machine, that is, from the start of excavation of the ground. In this case, since crushing and mixing are performed at the same time, the solidification of the earth and sand can be accelerated.

In addition, mixing after the completion of excavation is carried out by repeating reverse and forward rotation of the excavation rod 1 at regular intervals and by reciprocating it in the vertical direction, thereby creating convection between the soil and solidification material in the horizontal and vertical directions. This allows a more homogeneous and better mixing state to be obtained.

(Effects of the Invention) The present invention is as described above, and by rotating the casing rotatably connected to the outside of the digging rod in the opposite direction to the digging rod, the crushing material protruding from the inner circumferential surface of the casing is rotated in the opposite direction. Since the blades work with the stirring blades to crush the excavated soil to at least a certain size before mixing it with the solidification material, it is possible to produce a homogeneous solidified body without leaving any clods.

[Brief explanation of the drawing]

FIGS. 1-1 and II are a cross-sectional view and a vertical cross-sectional view, respectively, showing a drilling rod according to the present invention, and FIG. 2 is a vertical cross-sectional view showing another example of how a drilling rod may be assembled. 1...Drilling rod, 2...Casing, 3...Drilling bit, 4...Stirring blade,
5...Crushing wing.

Claims (1)

[Claims] (1) A drilling rod with stirring blades protruding above the drilling bit at the tip, rotatably connected to this drilling rod, and crushing blades protruding alternately with the stirring blades on the inner peripheral surface of the stirring blade position. The cylindrical casing is rotated in the opposite direction, and the ground is excavated while crushing the excavated soil with stirring blades and crushing blades. After reaching a predetermined depth, the soil is excavated while discharging solidified material from the tip of the excavation rod. This is a ground improvement method in which the rod and casing are rotated in the opposite direction to the direction of excavation, and the excavated soil is further crushed using stirring blades and crushing blades, and at the same time, the crushed earth and sand and solidification material are stirred and mixed to form a solid body.