JPS5841225Y2 - stirring bit - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a stirring bit used in implementing a deep ground improvement method.

Conventionally, when constructing structures such as quays on soft ground,
A replacement method that removes soft and viscous material and replaces it with sand and gravel, etc.
Drain construction methods are used to increase the strength of the ground by driving sand piles and other materials to consolidate and dewater.

However, in recent years, there have been many issues such as emphasis on environmental conservation such as prevention of seawater pollution, depletion of good quality sand, increase in construction work under deep water, and increase in the thickness of soft/weak layers. A highly efficient ground improvement method is required.

In order to meet these demands, a deep ground improvement method has been developed in which a cement-based stabilizing agent is injected into soft ground through a stirring blade and continuously kneaded to improve the ground, and has achieved some success.

However, in the past, deep soft ground improvement methods were
Since it was mainly used to improve ultra-soft ground such as the seabed, the digging power of the stirring bit used for this is weak, and therefore it is difficult to use in sandy layers with a relatively high N value or in strata near the supporting layer. This has the disadvantage of slowing down the excavation penetration speed, changing the mixing ratio of the cement-based stabilizing agent and the soil to be improved, which are supplied at a constant rate due to gravity, etc., and reducing work efficiency.

This idea was made in view of the above, and aims to provide a stirring bit that can drill holes at a constant design penetration speed in any geological formation, and that can uniformly stir and mix a treatment agent onto the object to be improved. With the goal.

This invention consists of a stirring bit consisting of three parts: a drilling blade, a dispensing tool for improved processing agent, and a stirring blade, and the gist is that the rake angle of the blade and the angle of the stirring plate provided on the blade are improved. It is something.

This invention will be explained in detail below with reference to the drawings.

The drawing shows an embodiment of this invention, and the stirring bit of this invention is composed of a digging blade 1, a discharge tool 2, and a stirring blade 3.

The excavation wing 1 mainly excavates the ground when penetrating into the ground,
It also stirs the soil to be improved and the treatment agent when it is pulled out from the ground, and the lower rod 5 has biting teeth 4 at the lower end.
Three excavating blades 10 having tips 6, 7 for excavating the ground and lower stirring plates 8, 9 for stirring the soil to be improved and the treatment agent are spaced at an interval of 120° around the
It is manufactured by attaching it radially with a positive rake angle α and a positive blade angle β.

Chip 6.7 above is for directly excavating the soil to be improved.
Usually made of cemented carbide.

Further, the above-mentioned stirring plate 8 moves the soil to be improved, which is raised by the rotation of the excavating blade 10 in the clockwise direction in FIG. Change the direction with , break it up and stir it up and down, and then use another stirring plate 9.
The soil to be improved, etc., which is about to be scattered outward by centrifugal force, is turned in a substantially horizontal plane toward the center of rotation of the excavation blade 10, that is, toward the lower rod 5, and is crushed and agitated from side to side. It is supposed to be done.

Although the rake angle α of the excavating blade 10 is set to 45° and the blade angle β is set to 5°, the present invention is not limited to this.

Further, the discharging tool 2 is used to inject a treatment agent such as a cement-based stabilizing agent into the soil to be improved, and has two discharging tools 12 around an intermediate rod 11, each having a discharge nozzle 12 for discharging the treatment agent and a stirring blade 13. The discharge blade 14 is set at a positive rake angle α1
It is manufactured by attaching a discharge nozzle 12 radially in communication with a processing agent passage 15 formed in the intermediate rod 11.

Note that the discharge nozzle 12 is opened at the rotationally rearward side of the discharge blade 14.

On the other hand, the stirring blade 3 is mainly used to stir and mix the soil to be improved and the treatment agent, and this is carried out by the hollow shaft 16.
17, 18, and 19.2, respectively)
Two main stirring blades 21 and two auxiliary stirring blades 22 having a diameter of 0 are installed alternately and radially at intervals of 90°.

The above-mentioned auxiliary blade 22 is attached to the shaft 16 with a positive rake angle α3 like the excavation blade 10 etc., but the main blade 21 is attached to the shaft 16 with a negative rake angle α2, contrary to this. ing.

In addition, the stirring plate 17.18 of the main blade 21 is attached to the upper surface of the main blade 21 in a conical shape by narrowing the rotation front side of the main blade 21, and the auxiliary blade 22
(Agitation play) 19.20 is attached to the lower surface of the auxiliary blade 22 with the rotation front side of the auxiliary blade 22 opened and opened at the front.

Note that the rake angle α1 of the discharge blade 14 is 65°.
Also, the rake angle α2. of the blades 21, 22. α3
are both set at 75°, but the digging blade 10
As in the case of , it is not limited to the above.

The numbers of the blades 10, 14, 21, and 22 are also similar and are not limited to those shown in the figures.

The excavation blade 1, discharge tool 2, and stirring blade 3 configured as described above connect the intermediate rod 11 to the upper part of the lower rod 5,
Further, the hollow shaft 16 is connected to the upper part of the intermediate rod 11, and the whole is assembled integrally, and used in the same manner as the conventional stirring bit to carry out the deep ground improvement method.

Here, when two stirring bits are used as a set, as shown in FIG. 1 and FIG. Generally, the stirring blades 3 and discharge tool 2 of the stirring bit 1 and the other stirring bit are located between the drilling blade 1 and the drilling blade 1, and the phases of the blades of the two stirring bits are shifted by 90 degrees.

Next, the operation of the stirring bit configured as described above will be explained.

The stirring bit of this invention is prepared by assembling it as described above, attaching it to the lower end of the stirring shaft (not shown), and connecting the hollow shaft 16 to the supply source of the processing agent through the stirring shaft. Then, the stirring bit is rotated together with the stirring shaft by the drive device, and the processing agent such as mortar is discharged from the discharge nozzle 12 and lowered into the target ground.

A hole is dug in the ground by the above operation, and a treatment agent is mixed into the soil to be improved.

That is, the biting teeth 4 first bite into the ground to prevent and stabilize the stirring bit from swinging laterally, and then the tips 6.7 excavate the ground.

At this time, the excavating blade 10 of the excavating blade 1 is moved upward over the improvement target excavated above, and a part of the excavating blade 10 is moved in the rotational tangential direction of the blade 10 by the action of the lower stirring plate 8, so that it is almost perpendicular to the surface. At the same time, the other part is stirred in a nearly horizontal plane toward the center of rotation of the blade 10 by the action of another lower stirring plate 9.

Further, the discharge tool 2 following the excavation blade 1 enters the soil to be improved which has been excavated and stirred by the excavation blade 1 and helps the agitation with the stirring blade 13, and at the same time, the discharge tool 2
The processing agent is discharged from the container and mixed onto the object to be improved.

Furthermore, the stirring blade 3 enters above the soil to be improved into which the treatment agent has been mixed, and the main stirring blade 21 moves the soil to be improved downward, and the upper stirring plate) 17.18
The soil to be improved is stirred by being pushed to the center and outward of the stirring blades 3.

The auxiliary stirring blade 22 provided in this part acts exactly in the opposite direction to the main stirring blade 21 of the stirring blade 3 to move the soil to be improved upward, and also works as an upper stirring plate.
By 9.20, the soil to be improved is collected in the middle part of the blade 22, and in cooperation with the stirring blade 3, the soil to be improved and the treatment agent are uniformly mixed.

As explained above, since the stirring bit of this invention has biting teeth 4 and tips 6.7 on its drilling blade 1, it can be used without causing lateral vibration even in sandy layers with high N values and strata near supporting layers. The ground can be excavated at a constant penetration speed.

Therefore, it is possible to carry out the deep ground improvement work efficiently, and to obtain the ground having the desired strength in which the treatment agent is evenly mixed.

Further, the excavating blade 1 is provided with a stirring plate 8.9, and the main stirring blade 21 of the agitating blade 3 is provided with a negative rake angle α3 opposite to that of the excavating blade 1, so that stirring is performed completely. Treating agents do not accumulate in the center or outer periphery of the stirring bit, and in this respect as well, homogeneous improved soil can be obtained.

[Brief explanation of drawings]

The drawings show an embodiment of this invention; FIG. 1 is a front view of the stirring bit of this invention, FIG. 2 is a side view, and FIG. 3 is a plan view. 1...Drilling blade, 2...Discharge tool, 3...
... Stirring blade, 4 ... Biting tooth, 5 ...
...Lower rod, 6,7...Tip, 8...
... Lower stirring plate, 9 ... Lower stirring plate, 10 ... Excavation blade, 11 ...
...Intermediate rod, 12...Discharge nozzle, 14.
...Discharge blade, 15...Passway, 1
6...Hollow shirt), 17.18...
Upper stirring plate, 21... Main blade for stirring, α, α3... Rake angle.

Claims (1)

[Scope of utility model registration request] A plurality of excavation blades are provided radially at a positive rake angle on a lower rod having biting teeth at the lower end, and the excavation blades include a tip for excavating the ground and a lower stirring plate for stirring the soil to be improved and the treatment agent. a digging wing provided with;
A discharge blade having a treatment agent discharge nozzle is attached to an intermediate rod connected to the upper part of the means rod of the excavation blade so that the discharge nozzle communicates with a treatment agent passage formed in the intermediate rod. A main stirring blade is provided radially at a negative rake angle on a hollow shaft connected to the upper part of the intermediate rod of the discharging tool, and the stirring blade is used to stir the treatment agent and the surface to be improved. A stirring bit characterized by comprising: a stirring blade having an upper stirring plate.