JP3247757B2 - Cement milk injection downhole hammer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a cement milk injection type in which a cement hole can be injected into a casting hole while a downhole hammer is being pulled out from the hole after excavating a setting hole of a foundation pile. About downhole hammer.

[0002]

2. Description of the Related Art In civil engineering and construction work, a construction method using a boring device equipped with an auger screw has been performed as a conventional construction method for forming a foundation pile for supporting a structure on the spot. This method employs a method of pouring cement milk into a casting hole through a hollow auger screw shaft at the same time that the auger screw is pulled up after excavating the setting hole of the foundation pile with the auger screw. As a boring device, a drilling device called a downhole hammer is used in addition to the auger screw. This downhole hammer is used by attaching it to the lower end of a rotating shaft (such as the screw shaft of an auger screw) that is supported so that it can move up and down. Because it has a structure that rotates while being hit, it can easily excavate even on hard ground where the auger screw has no bottom teeth.

[0003]

However, in the case of a downhole hammer, unlike the auger screw, a simple construction method of injecting cement milk while pulling up the excavated downhole hammer cannot be adopted. This is because the conventional downhole hammer has a structure in which there is no room for providing a downflow passage of the cement milk inside the hammer, and the cement milk cannot reach the lower end of the downhole hammer. Accordingly, an object of the present invention is to provide a cement-milk-injection-type in which, as in the case of the auger screw, when the installation hole of the foundation pile is dug and pulled up, cement milk as a material for the foundation pile can be simultaneously injected. There is in providing downhole hammer.

[0004]

In order to achieve the above object, a cement-milk-injected downhole hammer according to the present invention is used by being connected to the lower end of a hollow rotary shaft 3. A cement milk feeding path 8 is formed in the shaft 3 at an inner space thereof, and a spiral blade 17 for discharging the earth is protruded from an outer peripheral surface of the casing 10 of the downhole hammer 1, and the spiral blade 17 is hollow. And the inner space thereof is used as a cement milk flow path 18.
The upper end 18a is connected to the lower end of the cement milk feeding passage 8 so that the open lower end 18b of the cement milk flow path 18 faces the lower end of the downhole hammer 1. Alternatively, a spiral blade 17A for discharging the earth is protruded from the outer peripheral surface of the casing 10 of the downhole hammer 1, and a tubular member 27 having an inner space serving as a cement milk injection path is provided.
The upper end of the tubular member 28 is connected to the lower end of the cement milk feeding path 8 along the entire length of the spiral blade 17A, and the open lower end 28b of the tubular member 28 is located near the lower end of the downhole hammer 1. May be adopted. The hollow rotary shaft 3 may be assigned to the auger screw shaft of the auger screw 2.

[0005]

[Function] To excavate a driving hole for a foundation pile, use the hollow rotary shaft 3
When the air hammer incorporated in the downhole hammer 1 is actuated while its driving means is being rotated, the drill bit attached to the lower end of the downhole hammer 1 is rotated while being repeatedly hit, and the solid ground is efficiently moved. Dig into When the excavation is completed, the downhole hammer 1 is pulled up while supplying cement milk to the inner space of the hollow rotary shaft 3, and reaches the lower end of the hollow rotary shaft 3, and the cement milk reaches the lower end of the casing 10 of the downhole hammer 1. It flows into the cement milk flow path 18 formed in the inner space of the spiral blade 17 protruding from the outer peripheral surface from its upper end 18a and strikes from its open lower end 18b located near the lower end of the downhole hammer 1. It is filled in the hole. And
When the tubular member 27 is placed along the solid spiral blade 17A, the cement milk flows down from the lower end of the hollow rotary shaft 3 along the inner space of the tubular member 27, and the lower end of the downhole hammer 1. And is injected into the casting hole.
When the screw shaft of the auger screw 2 is used as the hollow rotating shaft 3, the excavation by the downhole hammer 1 is performed by the spiral blade 1 provided on the outer peripheral surface of the casing 10.
7, 17A and the auger screw provided on the auger screw 2 cooperate to extrude the ground.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, the downhole hammer 1 of this embodiment is used with its upper end detachably connected to the lower end of an auger screw 2. FIG.
2 shows the overall configuration of the excavator to which the downhole hammer 1 is attached. In the figure, reference numeral 50 denotes a machine main body provided with a caterpillar 51 for movement. A leader 53 supported by two reader stays 52 is provided upright at the front of the machine main body 50. The leader 53 has an earth auger 54
Is mounted so as to be able to move up and down along a guide rail (not shown) provided over substantially the entire height of the leader 53. And, a winch (not shown) installed inside the machine body 50
The auger suspension wire 55 fed from the wire is extended over a wire sheep 56 provided at the upper end of the leader 53 and extended downward, and the ground auger 54 is provided at its end.
Is suspended.

An auger motor 57 with a speed reducer is incorporated inside the earth auger 54, and the upper end of the auger screw shaft 3 of the auger screw 2 is connected to the output shaft. In this embodiment, the auger screw shaft 3 corresponds to the hollow rotary shaft referred to in the present invention, and an auger screw blade 4 for discharging the earth is provided on the outer peripheral surface thereof. At the lower end of the auger screw shaft 3, a coupler 5 for detachably connecting the upper end of the downhole hammer 1 described below is attached as shown in FIG. The coupler 5 is provided with a female screw 6 for connecting the downhole hammer 1.

[0008] Inside the auger screw shaft 3, compressed air supplied from an air compressor not shown is
An air supply pipe 7 for feeding the downhole hammer 1 is arranged coaxially. The cylindrical gap around the air supply pipe 7 is defined as a cement milk supply path 8. At the upper end of the cement milk supply path 8, a hose joint (not shown) for connecting the end of a pressure feeding hose extending from the cement milk supply device is provided. The lower end of the cement milk supply passage 8 is communicated with a delivery hole 9 provided in the coupler 5 so as to penetrate vertically.

Downhole hammer 1 shown in FIGS.
Has a cylindrical casing 10 in which a piston (hammer) 11 that is loosely fitted and moves up and down repeatedly hits a drill bit 12 that is loosely fitted to a lower part of the casing 10. It has become. The piston 11
The compressed air is supplied to the upper and lower sides of the piston 11 alternately by the cooperation of the air valves 13 and 14 provided on the upper and lower sides of the piston 11 to be moved up and down. A plug 15 is screwed onto an open upper end of the casing 10, and a male screw portion 1 screwed to a female screw 6 provided at a lower end of the auger screw shaft 3 is provided on the upper surface thereof.
6 are protruding. Also, on the outer peripheral surface of the casing 10,
A spiral blade 17 for discharging the earth is mounted over the entire height. The pitch and outer diameter of the spiral blade 17 are the same as those of the auger screw blade 4.

The spiral blade 17 of this embodiment is formed in a rectangular cylindrical body or a gutter-like body having a U-shaped cross section as shown in FIG. The empty portion is defined as a cement milk flow path 18. The spiral blade 17 is not limited to the square tube shape, but may be formed into a triangular tube shape, a cylindrical shape, or the like. Is also good.

As shown in FIG. 2, the drill bit 12 of this embodiment has a shaft portion 21 that forms the upper half thereof as a spline shaft, and each ridge is formed on the inner peripheral surface of the lower portion of the casing 10. It is fitted into each circumferential groove. Therefore, the drill bit 12 can be rotated integrally with the casing 10 and can be moved up and down with respect to the casing 10. An annular groove 22 is provided around the upper end of the shaft portion 21, and a retainer ring 23 provided at a lower portion in the casing 10 is protruded into the annular groove 22 to regulate a vertical movement stroke of the drill bit 12. are doing.

A bit main body 24 constituting the lower half of the drill bit 12 is formed in a thick disk shape, and a plurality of vertical grooves 25 are provided on the outer peripheral surface thereof at equal intervals in a vertically penetrating manner. ing. The vertical groove 25 serves as a discharge path for pushing up moat dust toward the surface of the ground when excavating, and serves as a flow-down path when cement milk is injected. A large number of excavating chips 26 are planted on the bottom surface and the outer peripheral surface. Further, an exhaust hole 27 serving as an escape path for the used compressed air is provided in the shaft core portion of the excavation bit 12 so as to penetrate vertically.

Next, the operation of the above configuration will be described. First,
In order to excavate a driving hole for driving a foundation pile, the machine body 50 is used.
Move the winch and operate the winch to
When the auger screw 2 is brought to the excavation point on the ground surface, the auger motor 57 is activated, and compressed air is supplied to the downhole hammer 1, the auger screw 2 and the downhole hammer 1 connected to the lower end thereof start rotating.
For this reason, the excavation bit 12 assembled to the downhole hammer 1 rotates and excavates the ground while being repeatedly hit by the air hammer. The cuttings generated along with the excavation are pushed upward through the vertical grooves 25 provided in the excavating bit 12, and are driven to the lower end of the auger screw 2 by the action of the spiral blade 17 provided on the outer peripheral surface of the downhole hammer 1. Pushed up. The excavated waste is transferred to the auger screw blade 4 of the auger screw 2 and discharged to the ground.

After digging a casting hole having a predetermined depth, the cement milk feeding device is operated, and the earth auger 54 is pulled up by a winch. Through the cement milk supply path 8 and the delivery hole 9 provided in the coupler 5, the cement milk flows from the upper end 18a of the cement milk flow path 18 formed in the spiral blade 17 into the flow path. And an open lower end 18 located near the lower end of the downhole hammer.
The cement milk discharged from b flows down in the vertical groove 25 provided on the outer peripheral surface of the drill bit 12, and is filled in the cavity (casting hole) generated as the downhole hammer 1 is pulled up.

When the downhole hammer 1 is completely lifted to the ground and the casting hole of the foundation pile is filled with cement milk, the H-shaped steel is poured into the casting hole filled with cement milk in the same manner as in the conventional method. If a steel pipe or the like is pushed in, the construction of the foundation pile is completed very easily and quickly, and without significant noise and vibration.

FIG. 5 shows another embodiment of the present invention. The difference from the above embodiment is that a solid spiral blade 17A is used and the tubular member 27 is replaced with the spiral blade 1A.
7A. in this case,
The inner space of the tubular member 27 serves as a cement milk flow path. The upper end of the tubular member 27 communicates with the delivery hole 9 provided in the coupler 5. Tubular member 27
Is not limited to the illustrated circular shape, and may be, for example, a triangular cylindrical shape.

In the above-described configuration, the object of the present invention can be achieved even if the detailed configuration is appropriately changed in design. For example,
In the case where the compressed air is hardly dissipated unlike sandy or gravel soil and is dedicated to a solid ground, a simple hollow rotary shaft 3 is used instead of the auger screw 2 and the used compressed air of the downhole hammer is used. Alternatively, the spiral blades 17 may cooperate with each other to perform earth discharging. Further, as a method of connecting the hollow rotary shaft 3 and the downhole hammer 1, a connecting bolt may be used instead of the screw connection. Alternatively, the lower surface of the excavation bit 12 may be formed in a conical surface, a frusto-conical surface, or the like, depending on properties such as hardness of the excavated ground.

[0018]

As is apparent from the above description, the downhole hammer of the cement milk injection type according to the present invention uses the inner space of the hollow rotary shaft for rotating the downhole hammer as the cement milk feeding path, and A spiral blade attached over the entire height of the outer peripheral surface of the casing of the downhole hammer is formed in a hollow shape, and the inner space is used as a flow path for cement milk, or a tube serving as a flow path for cement milk. The shaped member is attached over the entire length of the spiral blade,
With the configuration in which the upper end of the hollow spiral blade or the tubular member is communicated with the lower end of the hollow rotary shaft, various excellent effects in practical use as listed below are exhibited. (A) In the case of digging a foundation hole of a foundation pile using an auger screw, it is possible to inject cement milk into a casting hole through a hollow screw shaft while pulling up the auger screw from the hole that has been dug. The extremely efficient foundation pile driving method will be applicable to the excavation method using a downhole hammer, which was impossible in the past. (B) Therefore, the above-mentioned extremely efficient construction method can be applied to hard ground that can only be dug unless it is a downhole hammer, as in the case of a screw type excavator that can be used only for soft ground. Become. (C) If an auger screw is used as a hollow rotating shaft for rotating the downhole hammer, the excavated waste is extruded to the ground by the spiral blade provided on the outer peripheral surface of the downhole hammer and the auger screw blade. Give me (D) Therefore, as in the past, the method of pushing out excavated waste using the used compressed air of a downhole hammer requires a large-capacity compressor in the case of sandy or gravel ground where the compressed air is remarkably dissipated. Eliminates the problem of need.

[Brief description of the drawings]

FIG. 1 is a side view of the entire apparatus, showing one embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the downhole hammer according to the first embodiment.

FIG. 3 is a side view of the downhole hammer.

FIG. 4 is an enlarged vertical sectional view showing the vicinity of the upper end of the spiral blade.

FIG. 5 is a diagram corresponding to FIG. 4, showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Downhole hammer 2 Auger screw 3 Auger screw shaft (hollow rotating shaft) 4 Auger screw blade 5 Coupler 6 Female screw 7 Air supply pipe 8 Cement milk feeding path 9 Delivery hole 10 Casing 11 Piston 12 Drilling bit 13,14 Air valve 15 Plug 16 Male screw part 17, 17A Spiral blade 18 Cement milk flow path 21 Shaft part 22 Annular groove 23 Retainer ring 24 Bit body 25 Vertical groove 26 Drilling tip 27 Tubular member 50 Machine body 51 Caterpillar 52 Backstay 53 Leader 54 Earth Auger 55 Auger Suspended Wire 56 Wire Sheep 57 Auger Motor

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) E02D 3/12 101 E21B 4/14 E21B 7/00

Claims (3)

(57) [Claims] The hollow rotary shaft is connected to a lower end of the hollow rotary shaft. The hollow rotary shaft has a cement milk feeding passage formed in an inner space thereof. A spiral blade 17 for discharging the earth is protruded from the outer peripheral surface of the casing 10. The spiral blade 17 is formed in a hollow shape, and an inner space thereof is used as a cement milk flow path 18. The upper end 18a is connected to the lower end of the cement milk supply passage 8, and the open lower end 18b of the cement milk passage 18 is connected to the downhole hammer 1.
A cement-milk-injected downhole hammer facing the lower end of the hammer. 2. The hollow rotary shaft 3 is used by being connected to a lower end thereof. The hollow rotary shaft 3 is provided with a cement milk feeding path 8 in an inner space thereof. A spiral blade 17A for discharging the earth is protruded from the outer peripheral surface of the casing 10, and a tubular member 27 having the inner space thereof as the cement milk flow path 18 extends along the entire length of the spiral blade 17A. The upper end of the tubular member 27 is connected to the lower end of the cement milk feeding path 8, and the open lower end of the tubular member 27 faces the vicinity of the lower end of the downhole hammer 1. Cement milk injection downhole hammer. 3. The downhole hammer of claim 1 or 2, wherein an auger screw shaft of an auger screw 2 is used as said hollow rotary shaft 3.