JPH06306859A - Fixing method of drilling anchor - Google Patents

Abstract

PURPOSE:To make such a case that water and mud are penetrated into a casing as a bit is separated in the midway of digging and thereby quality in a hardening material is deteriorated, etc., so as not to occur. CONSTITUTION:A groove 4 is installed in either the side of a casing 2 or a bit 3 and a hook projection 7 in the other, respectively, and this bit 3 is fitted in a tip of the casing 2, then the hook projection 7 and the groove 4 are engaged with each other, thereby assenbling a digging pipe 1. This digging pipe 1 is moved on the ground and a drilling hole 14 is made in the ground 13. After it is dug into the specified depth, a plug body 15 is dropped in the casing 2, closing a water hole 8 at a bit tip. A tension material 16 of an anchor is put in the casing 2, and a hardening material 17 is filled up. In this state intact, further this hardening material 17 is pressurized and poured thereinto, enhacing the extent of internal pressure, whereby the bit 3 is separated from the casing 2. The hardening material 17 is penetrated around the drilling hole 14 against water pressure. During digging operation, the bit 3 is not separated, and the hardening material 17 is pressurized and poured thereinto, through which the internal pressure is heightened enough, and the bit 3 is separated by dint of this pressure. In a state of being pressurized, no water is penetrated into the casing 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of fixing an anchor in a drill hole, and particularly to a drilling pipe which employs a disposable bit and which is capable of favorably filling a hardened material in the drill hole. The present invention relates to a method of fixing a hole anchor.

[0002]

2. Description of the Related Art In order to excavate a hole in a relatively soft ground such as a gravel layer, a drill pipe having a disposable bit fitted to the tip of a casing is sometimes used. This drill pipe is driven directly with a hammer while holding it on the ground,
Wrap a cloth around the bit and push it into the tip of the casing to prevent it from coming off during excavation. After driving the excavation pipe, insert a rod-shaped instrument into the casing to remove the bit at the tip, then place an anchor in the casing, inject a hardening material such as cement milk, and pull out the casing from the drilled hole. It is a thing.

[0003]

A problem with such a method is that the quality of the hardened material becomes poor due to water spouting from the ground into the drilling hole. That is, when excavating in a place deeper than the water surface, water blows up into the drilling hole with a considerably large pressure. In such a case, if you drop the bit without filling the casing with anything,
Water will enter the casing together with the mud. Even if the hardening material is filled in the casing after this, the mud prevents the hardening material from filling the casing well. Even if the casing is pulled out and the hardened material is expected to adhere to the ground around the drilled hole, it cannot be expected to adhere to the ground as designed because it is a defective hardened material.

In the conventional excavation pipe, in order to prevent the bit from coming off during the excavation, the bit is wrapped as described above to prevent the bit from coming off during the excavation. Even if the bit did not come off until the end, when the bit was removed, water suddenly entered the casing along with the mud, and the cement was hardened to harden the hardening material in the mud and water. A large amount of hardeners such as water glass are used, and the cost is enormous.

The present invention has been made to solve the above problems, and the bit does not easily come off from the casing, and when it is no longer needed, it can be reliably removed. An object of the present invention is to provide a method of fixing a hole-drilling anchor that can be filled with a high-quality hardening material without water inside.

[0006]

In the method of fixing a drill anchor according to the present invention, a bit is attached to a casing so as not to be easily separated, and the bit is separated by a hardening material that has been pressed, and the hardening material is left as it is. Is pressed into the surrounding ground. First, a groove is formed on either the inner peripheral surface of the cylindrical casing side or the outer peripheral surface of the bit having a water passage hole at its tip, and a hooking protrusion is formed on the other. An O-ring or a C-shaped spring can be used as the hooking protrusion. Here, the term “casing side” or “bit side” means that it may be provided substantially on the casing side or bit side.
The bit is fitted into the tip of the casing, and one hooking protrusion is engaged with the other groove to prevent the hook from falling off. At this time, the bit does not easily come off, but if a certain amount of pressure or more is applied to the inside, the catching convex portion comes out of the groove and the bit comes off. The excavation pipe is assembled in this manner, and the excavation pipe is grasped on the ground and driven into the ground. At the time of driving, the water that has passed through the casing is sent through the water holes into the hole and the excavated soil is discharged to the ground.

After excavating the drilled hole by driving to a predetermined depth,
Drop the plug that blocks the water passage of the bit into the casing. The plug may be a steel ball or a spindle-shaped weight. After this, an anchor is inserted into the casing and a hardening material such as cement milk is also filled. While the casing is covered on the ground and the inside of the casing is sealed, the hardening material is further pressed into the casing. This increases the pressure inside the casing, and this pressure causes the hooking protrusions to come off the grooves, causing the bit to fall out of the casing. Subsequently, the hardening material is sent, and the hardening material is injected into the surrounding ground at the bottom of the drilled hole against the pressure of the ground water. In this state, the casing is pulled out from the drilled hole, and the anchoring by the hardening of the hardening material is waited for. However, in some cases, without using the plug, the internal pressure can be increased and the bit can be dropped by pumping the hardening material more than it flows from the water passage hole.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on an embodiment shown in the drawings. In the figure, reference numeral 1 is a drill pipe, which is composed of a casing 2 and a bit 3. The casing 2 is a tubular body made of steel, and the bit 3 is a disposable member made of casting. A groove 4 continuous in the circumferential direction is formed in the inner periphery of the tip of the casing 2. Casing 2 in the embodiment
The groove 4 is recessed in the bit catcher 5 integrated with the above, and the groove 4 is substantially recessed in the tip of the casing 2.

A taper groove 6 is similarly provided on the outer circumference of the bit 3 so as to be continuous in the circumferential direction. What is the taper groove 6?
As shown in FIG. 2, the groove has a depth that gradually decreases as it moves away from the tip, and the bottom surface is formed in a tapered shape. The shallowest part of the taper groove 6 is O which will be described later.
It forms a concave surface having the same radius R as the arcuate peripheral surface of the ring.
An O-ring 7 is fitted in the groove 6. A water passage hole 8 penetrates through the tip of the bit 3, and a receiving member 10 having a valve hole 9 at the center is screwed into the base end of the bit 3.
The valve ball 12 pushed by the coil spring 11 is housed in the space between the receiving member 10 and the inside of the tip, and the valve ball 12 constantly closes the valve hole 9 of the receiving member 10 by the spring force.
Further, the valve hole 9 of the receiving member 10 has a tapered peripheral surface so that the diameter of the inner circumference gradually increases toward the end.

The bit 3 as described above is inserted into the bit catcher 5 at the tip of the casing 2, and the O-ring 7 on the outer periphery of the bit 3 is engaged with the groove 4 of the bit catcher 5. When the O-ring 7 is fitted, the O-ring 7 is located on the deep side of the groove 6 and the ring 7 is retracted so that the O-ring 7 can be fitted easily. It is located on the shallow side and is pushed out by bit 3 and does not easily come off. Further, at this time, the peripheral surface of the O-ring 7 contacts the concave surface of the groove 6 and is difficult to be crushed.

The excavation pipe 1 assembled as described above is grasped on the ground and driven into the ground 13 by a hammer. Drilling 14
Water is fed through the casing 2 during excavation. Water pushes the valve ball 12 against the force of the spring 11 in the bit 3, flows through the water passage hole 8 into the drilled hole 14, and carries the excavated soil to the ground. (FIG. 3) After excavating to a predetermined depth, the plug body 15 is dropped into the casing 2. In the embodiment, a steel ball is used as the plug body 15. The stopper 15 travels along the tapered peripheral surface of the inside of the receiving member 10, accurately hits the center of the valve hole 9, and closes the valve hole 9. (FIG. 4) A tension member 16 of an anchor is inserted and arranged in the casing 2, and cement milk 17 which is a hardening material is filled therein. (FIG. 5) Thereafter, the end of the casing 2 is covered with the pressure head 18 on the ground, and the cement milk 17 is pressure-fed to increase the pressure in the casing 2. Due to this pressure, the O-ring 7 of the bit 3 is removed from the groove 4 of the bit catcher 5, and the bit 3 is detached from the casing 2.
(FIG. 6) The pressed cement milk 17 is further drilled 14
Flows into the ground and penetrates into the surrounding ground. In this state, the casing 2 is pulled out from the drilled hole 14, and the tension material 16 is fixed after waiting for the cement milk 17 to harden.

[0012]

Since the present invention has the above-mentioned structure, the following effects can be obtained. Since the bit is attached by fitting the hooked protrusion into the groove, it does not easily come off and water and mud do not enter during excavation. Since the bit is removed by increasing the internal pressure of the casing, the bit is removed with the hardening material filled in the casing, water and mud do not enter the casing, and the anchor is fixed with a good hardening material. it can.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a bit and a tip of a casing.

FIG. 2 is a partially enlarged sectional view of a bit and a casing.

FIG. 3 is a cross-sectional view during excavation.

FIG. 4 is a cross-sectional view of a state in which the plug is dropped into the casing.

FIG. 5 is a sectional view showing a state in which an anchor is inserted.

FIG. 6 is a cross-sectional view of a state in which the bit is separated by pressurizing the inside of the casing.

[Explanation of symbols]

 1 Drilling Pipe 2 Casing 3 Bit 4 Groove 5 Bit Catcher 6 Tapered Groove 7 O-ring 8 Water Passage 9 Valve Hole 10 Receiving Member 11 Coil Spring 12 Valve Ball 13 Ground 14 Drilling Hole 15 Plug 16 Tension Material 17 Cement Milk 18 Pressurization head

Claims (2)

[Claims] 1. A bit is fitted to the tip of the casing by forming a groove in either the inner circumference of the cylindrical casing side or the outer circumference of the bit side where a water passage hole penetrates at the tip, and by forming a hooking protrusion on the other side. Assemble a hooking projection that engages with the groove to prevent it from falling off, operate this drilling tube on the ground to drill a hole, and after drilling to a specified depth, plug the water hole of the bit. The body is dropped into the casing, the tension material of the anchor is placed in the casing and filled with the hardening material, and the hardening material is further pumped while the casing is sealed on the ground to increase the internal pressure and the pressure of the hardening material. A method for fixing a drill anchor, comprising: dropping the bit from the tip of the casing by the method, subsequently press-fitting the hardened material around the bottom of the drill hole, and then removing the casing from the drill hole. 2. A bit is fitted to the tip of the casing by forming a groove in either the inner periphery of the cylindrical casing side or the outer periphery of the bit side where the water passage hole penetrates at the tip, and the hooking protrusion on the other side. As a result, the hooked protrusion is engaged with the groove to assemble an excavation pipe that prevents it from falling off.The excavation pipe is operated on the ground to make a hole, and after excavating to a predetermined depth, the tension material of the anchor is placed in the casing. Arrange it and fill it with the hardening material, and further pressurize the hardening material with the casing sealed on the ground to increase the internal pressure,
A method for fixing a drilling anchor, characterized in that the bit is dropped from the tip of the casing by the pressure of the hardening material, the hardening material is subsequently pressed around the bottom of the drilling hole, and then the casing is removed from the drilling hole.