JPS6111316Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a mixing head used in a soil improvement method.

As shown in Figure 1, in the conventional ground improvement pile construction method, the ground is excavated and stirred with a mixing head 2, and a solidifying agent such as cement grout is injected from the tip of the excavator to solidify the soil. However, in the case of coarse-grained soil such as a sand layer, it is relatively easy to stir, but in the case of clayey soil with a silt layer, a so-called co-rotation phenomenon occurs in which the clay adheres to the stirring blade 3 of the mixing head 2 and rotates with the head. This has the disadvantage that not only is it difficult to stir, but also that a path is formed underground, causing the injection material to blow out onto the ground. This sticky soil adhesion reduces the rotational speed of the head.
This can be prevented by increasing the rotation speed to over 150 rpm and applying centrifugal force, but since large machines generally have low rotation speeds, it is extremely difficult to increase the rotation speed and increase turning efficiency.

This invention improves the drawbacks of the prior art by replacing the conventional stirring blade above the drilling bit of the mixing head and making the shaft center eccentric to the crankshaft.

This invention will be explained below with reference to an embodiment shown in Fig. 2. 4 is a mixing head of this invention, in which the axis above the excavation bit of the head of a soil improvement machine is eccentrically centered in the shape of a crankshaft. , is characterized in that it has a bent shaft that stirs the inside of the borehole by rotating the shaft. Since the head of this invention is formed in this way, the centrifugal force works effectively even at relatively low rotation speeds, and since the trajectory of the stirring rod and the trajectory of the crankshaft are significantly different, the soil rotates at the same frequency. Since the head is bent rather than a straight line, there is less chance of the stirring liquid passing through the rod and blowing to the ground, which has the excellent effect of high stirring efficiency. .

Note that the crankshaft shape may be bent linearly as in the embodiment, but it may also be formed into a curved shape. Alternatively, it may be bent at right angles, but in this case the rotational resistance will be greater than that described above.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a soil improvement pile construction method using a conventional mixing head, and FIG. 2 is a front view of the mixing head of this invention. DESCRIPTION OF SYMBOLS 1... Rod, 2... Conventional mixing head, 3... Stirring blade, 4... Mixing head of the present invention, 5... Crankshaft-shaped portion, 6... Drilling bit.

Claims (1)

[Scope of utility model registration request] Mixing of a soil improvement machine characterized in that the shaft above the excavation bit of the head of the soil improvement machine is eccentrically shaped like a crankshaft, and a bent shaft part is formed to stir the inside of the excavation hole by rotation of the shaft. Head.