JPH0316955Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention uses a pressurized fluid (bentonite solution, high pressure air, cement milk, etc.) that opens at the lower end.For convenience, bentonite solution, cement milk, etc. ) has a supply flow path,
The present invention also relates to an auger head that is connected to the lower end of the earth auger shaft in such a manner that the pressurized fluid supply passages communicate with each other.

[Conventional technology]

When excavating an underground hole with an earth auger, a bentonite supply pipe is connected to the upper end of the pressurized fluid supply channel of the earth auger shaft, a bentonite solution is introduced into the pressurized fluid supply channel, and the bentonite solution is Means is provided for discharging from an auger head connected to the lower end of the earth auger shaft.

By arranging the opening in the pressurized fluid supply channel of the auger head to face the lower end of the head, the mixture (mixture of excavated soil and bentonite solution) present at the lower end of the excavated underground hole and the excavation blade at the lower end of the auger can be prevented from adhering to the auger head. This mixture can be effectively removed with a bentonite solution supplied at high pressure, and after the underground hole is formed, a cement milk supply pipe can be switched and connected in place of the bentonite supply pipe at the upper end of the earth auger shaft. However, by injecting cement milk into the underground hole filled with bentonite solution having a specific gravity lower than that of cement milk, it is possible to manufacture a high-strength underground pile in which no mixture is mixed at the lower end of the pile.

By the way, the length of a single earth auger shaft is currently about 6 to 8 m, and for example, to manufacture a 20 m underground pile, three to four earth auger shafts are connected in sequence.

At this time, the bentonite supply pipe is removed from the earth auger shaft that had been used for excavation until then, and a supplementary earth auger shaft is connected to the earth auger shaft, and the bentonite supply pipe is reconnected to the connected earth auger shaft. connect, and
Excavation means are used to supply bentonite solution at high pressure to the bentonite supply pipe and to rotate an earth auger shaft and auger head which are integrally connected.

[Problem that the invention attempts to solve]

When connecting the earth auger shaft, when the bentonite supply pipe is removed from the earth auger shaft, the upper end side of the pressurized fluid supply channel of the earth auger shaft that had been used for excavation is opened to the atmosphere.
In addition, because a large earth pressure is applied to the lower end opening of the pressurized fluid supply channel of the auger head, the mixture is injected into the pressurized fluid supply channel of the auger head, and this flows into the pressurized fluid supply channel. Then, even if bentonite solution was injected from the bentonite supply pipe under considerably high pressure, the solidified mixture in the auger head could not be completely removed.
Conventionally, the auger head was unavoidably pulled out to the ground together with the earth auger shaft, and the clogged mixture was broken up with a rod-like body from the lower end opening of the pressurized fluid supply channel of the auger head while bentonite solution was being supplied under high pressure. It is evacuated using a high-pressure bentonite solution.

This mixture is removed all at once by the high-pressure bentonite solution when the rod-shaped body penetrates the packed mixture and a communication path is formed in the plug-shaped mixture.

However, this requires a great deal of effort and manpower, and leads to a decrease in excavation efficiency. Therefore, the applicant has developed an agitation system that allows the supply of bentonite solution to the tip opening of the pressurized fluid supply channel of the auger head. A one-way valve having a valve structure is provided, and when the bentonite supply pipe is removed, the one-way valve is closed based on earth pressure applied to the one-way valve, so as to prevent the mixture from flowing back into the pressurized fluid supply channel. This is an attempt at a technique to do this.

However, the one-way valve, which is open due to the supply of the bentonite solution, is easily damaged by the external force from the ground caused by the rotation of the auger head, and when the bentonite supply pipe is removed and the earth auger shaft is added, the mixture It was not possible to reliably prevent backflow.

The above situation also occurs when adding a supply pipe (changing the connection between the bentonite supply pipe and the cement milk supply pipe) when pouring cement milk after forming an underground hole, and it is necessary to propose a technology that can completely prevent the backflow of the mixture. Waiting.

[Means for solving problems]

The present invention has been devised in view of the above-mentioned circumstances, and can solve the problem of clogging of the mixture in the pressurized fluid supply channel by a new means that is completely different from conventional techniques. The auger head is not provided.

In order to achieve the above object, the present invention has an auger head that has a pressurized fluid supply channel that opens at the tip and is connected to the lower end of the earth auger shaft with the pressurized fluid supply channels communicating with each other. A one-way valve that prevents backflow of fluid in the pressurized fluid supply channel is provided, and a rod-shaped body whose tip protrudes from the lower end opening of the pressurized fluid supply channel is connected to the downstream side of the one-way valve. It has the following characteristics.

[Effect]

According to the characteristic configuration described above, by providing the one-way valve inside the pressurized fluid supply flow path, no external force to the ground due to the rotation of the auger head is applied to the one-way valve, and the function of the one-way valve is lost. You can avoid situations like this.

When connecting the ground auger shaft or cement milk, even if the mixture backflows into the switch and becomes clogged just before the one-way valve's check function is activated, it will not penetrate through the mixture and protrude from the tip of the auger head. As the auger head rotates, the rod-shaped body moves irregularly, forming pores penetrating the packed mixture and filling the pores with bentonite solution or cement. By flowing the milk under high pressure, the mixture is displaced by the bentonite solution and cement milk.

〔Example〕

Hereinafter, embodiments of the present invention will be described based on the drawings. FIG. 1 shows the lower end of an earth auger formed by connecting an auger head 2 to the lower end of an earth auger shaft 1. The earth auger shaft 1 is connected to a pressurized fluid Two helical bodies 5, 5 are provided on the outer peripheral surface of a shaft body 4 having a supply channel 3 with a phase of 180 degrees.

As shown in FIG. 2, the auger head 2 has two helical bodies 8, 8 arranged at a phase of 180 degrees on the outer peripheral surface of a shaft body 7 having a pressurized fluid supply channel 6 that opens at the lower end. and the spiral bodies 8, 8
Excavation blade bodies 9, 9, which protrude below the lower end of the shaft body 7, are integrally formed at the lower ends of each of the shaft members.

As shown in FIG. 3, a plurality of rectangular bar-shaped earth pressure cuts are provided on the lower end surface of the shaft body 7 without blocking the lower end opening A of the pressurized fluid supply channel 6. The blade bodies 10 are welded together, and a one-way valve V for suppressing backflow of fluid in the pressurized fluid supply channel 6 is built into the upper end side of the pressurized fluid supply channel 6.

This one-way valve V is constructed as follows.
That is, a large-diameter hole portion 1 is formed at the upper end of the pressurized fluid supply flow path 6, and rib-like portions for forming a flow path are formed on the inner peripheral surface of the large-diameter hole portion 11 at intervals in the circumferential direction. The bodies 12... are welded, and the rib-like bodies 12...
The spring receiving plate body 1 has a phase different from that of the spring receiving plate body 1.
3, a compression spring 14 is placed on the spring receiving plate 13, a spherical valve body 15 is placed on the compression spring 14, and a steel valve seat 16 for the spherical valve body 15 is placed on the spring receiving plate 13. With the spring 14 being bent and deformed, the shaft body 7
It is welded to the upper end of the.

Then, a hole a penetrating in the thickness direction is formed in the spring receiving plate 13, and a rod-shaped body 17 made of a highly elastic material such as a piano wire or a spring steel rod is connected to the tip thereof for supplying the pressurized fluid. It protrudes (for example, about 30 mm) from the lower end opening A of the flow path 6 and is locked therein.

Note that one of the plurality of earth pressure cutting blades 10 is located at the center of the pressurized fluid supply channel 6, and the tip of the rod-shaped body 17 is connected to the pressurized fluid supply channel. It is offset from the axis of the flow path 6.

The auger head 2 having the above configuration is attached to the gasket 18 with the pressurized fluid supply channels 3 and 6 communicating with each other.
connected to the lower end of the earth auger shaft 1 via
A bentonite supply pipe (not shown) is connected to the upper end of the earth auger shaft 1, and the auger head 2 is rotated while discharging bentonite solution at high pressure from the lower end opening A of the auger head 2, thereby excavating an underground hole. When forming a deep underground hole, the bentonite supply pipe is removed during excavation and another earth auger shaft is added.

At this time, the upper end of the pressurized fluid supply passage 6 of the earth auger shaft 1 is open to the atmosphere, and high earth pressure is applied to the lower end opening A of the auger head 2, so that the bentonite solution and the excavated soil As described above, the mixture is injected into the pressurized fluid supply channel 6 from the lower end opening A. The same applies when connecting the cement milk supply pipe instead of the bentonite supply pipe.

However, by providing the one-way valve V on the upper end side of the pressurized fluid supply channel 6, injection of the mixture into the pressurized fluid supply channel 6 can be effectively suppressed.

Alternatively, even if the check function by the one-way valve V is delayed in time and the pressurized fluid supply channel 6 is clogged with a mixture, the pressurized fluid supply channel 6 is filled with a high-pressure bentonite solution or cement. The auger head 2 is rotated in the underground hole while supplying milk to penetrate the clogged mixture and open the lower end opening A.
By irregularly agitating the rod-shaped body 17 protruding from the base, pores can be formed through the packed mixture, and the high-pressure bentonite solution or cement milk flows through the pores. This allows the clogging mixture to be easily removed.

[Effect of idea]

As explained above, the present invention provides an auger head that has a pressurized fluid supply channel that opens at the tip and is connected to the lower end of the earth auger shaft with the pressurized fluid supply channels communicating with each other. A one-way valve that prevents backflow of fluid in the pressurized fluid supply channel is provided, and a rod-shaped body whose tip protrudes from the lower end opening of the pressurized fluid supply channel is connected to the downstream side of the one-way valve. Therefore, the one-way valve can prevent the mixture from flowing back into the pressurized fluid supply channel, and even if the mixture injects into the pressurized fluid supply channel and solidifies, By rotating the auger head in the underground hole and agitating the rod-like body under the supply of pressurized fluid, the clogging of the mixture can be easily cleared, and as a whole, the mixture of concerns can be solved by a unique technique that has never existed before. This made it possible to solve the clogging problem.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a side view of the lower end of the earth auger taken longitudinally through the auger head;
FIG. 2 is a longitudinal sectional view of the auger head 2, and FIG. 3 is an end view of the auger head 2 on the opening side. DESCRIPTION OF SYMBOLS 1... Earth auger shaft, 3, 6... Pressurized fluid supply channel, 17... Rod-shaped body, A... Lower end opening, V... One-way valve.

Claims (1)

[Scope of utility model registration request] An auger head having a pressurized fluid supply channel that opens at its tip and connected to the lower end of an earth auger shaft in a state where the pressurized fluid supply channels communicate with each other, the pressurized fluid supply channel An auger head comprising a one-way valve that prevents backflow of fluid at the pressurized fluid supply channel, and a rod-shaped body whose tip protrudes from a lower end opening of a pressurized fluid supply channel and connected to the downstream side of the one-way valve.