JP7139100B2 - Method for injecting solidification agent into drilled hole and drilling rod - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method of injecting a solidifying agent such as a pile circumference fixing liquid mainly into the shaft portion of an excavated hole (pile hole), and an excavating rod used in this injection method.

When constructing foundation piles by burying prefabricated piles in pre-excavated pile holes, cement milk or the like should be placed between the side walls of the pile holes and the perimeter of the prefabricated piles in order to enhance the unity between the ground and the prefabricated piles. filled with hardener. When a pile hole is excavated, pile hole residues (excavated mud, lumps of surplus soil, water) remain in the pile hole, so it has been required to uniformly stir the solidifying agent. In addition, the solidification agent is discharged from a ground plant by supplying the solidification agent to the hollow part of the drilling rod and performing it from a discharge port provided near the lower end of the drilling rod (where the drilling head is mounted).

Especially in the hardened part of the pile hole, the quality of the hardening agent injection is directly linked to the tip bearing capacity. A contrivance has been made to stir the solidifying agent by moving the drilling rod up and down (Patent Document 1). Furthermore, recently, in order to increase the strength of the shaft, it is also required to make the solidification agent uniform at the shaft of the pile hole. There was also

In general, the discharge port of the solidification agent is arranged at the lower end of the excavation rod (lower end of the excavation head) (Patent Documents 1 to 3), and the discharge of the solidification agent to the pile hole shaft is usually performed by the excavation rod is discharged from the lower end of the drilling rod while pulling up the drilling rod, it is necessary to move the drilling rod significantly up and down in order to stir the solidifying agent protruding from the lower end of the drilling rod.

JP 2012-136875 A JP 2008-157014 A JP 2006-233749 A

As described above, when the excavation rod is pulled up while moving the excavation rod largely up and down, there is a problem that it takes time to pull up the excavation rod. Therefore, in the present invention, in order to omit or reduce the vertical movement of the excavation rod, there are two discharge ports, one near the lower end of the excavation rod for the foot protection portion and the other above the discharge port for the shaft portion. decided to set up

Further, in this case, there is a device for selecting a discharge port by providing a switching valve in the drilling rod (Patent Document 2), and a device for equipping the drilling rod with two pipes for upper and lower pipes (Patent Document 3). is proposed. In the former case, it is not practical to operate the switching valve from the ground, and in the case of the latter two systems of pipes, the connecting structure of the drilling rods becomes complicated, which is also impractical. Therefore, the present invention has a structure in which an operation piece is dropped into the solidifying agent supply pipe, and the flow path of the solidifying agent can be switched from the lower discharge port to the upper discharge port at the switching portion.

In the method of injecting the solidifying agent, the present invention forms an upper outlet near the lower end of the drilling rod and an upper outlet above the drilling head, and switches between the two outlets with a switching unit. In addition, in the drilling rod, a switching piece dropped from above into the solidifying agent supply pipe is used to switch from the lower discharge port to the upper discharge port, thereby solving the above problem.

That is, in the invention of this method, a drilling head mounted on the lower end of a drilling rod is used to drill a drilling hole, and a solidification agent is filled in the drilling hole as follows to form a high-strength solidification agent layer and a normal solidification layer in the drilling hole. A method of injecting a solidifying agent into a borehole characterized by forming an agent layer.
(1) The drilling rod is formed of a double cylinder consisting of an inner cylinder and an outer cylinder. Two liquid passages are formed, the drilling head is provided with a lower outlet communicating with the first liquid passage , and the drilling head is provided with an upper outlet communicating with the first liquid passage and normally closed. rice field.
(2) When the excavation of the excavated hole is completed, a solidifying agent is injected from the lower discharge port into the lower end of the excavated hole to replace the excavated hole residue and the solidifying agent, or Stir to mix with the residue.
(3) While pulling up the excavation rod, the solidification agent is injected from the lower discharge port to a predetermined height of the previously set excavation hole to form a high-strength solidification agent layer.
(4) Subsequently, a switching piece is introduced from above the first liquid passage to release the closure of the upper discharge port and close the liquid passage on the side of the lower discharge port, and the liquid passage from the lower discharge port to the upper discharge port. Switch the outlet to
(5) Injecting a solidifying agent into the excavated hole from the upper discharge port, and stirring the discharged solidifying agent with the residue in the pile hole while pulling up the excavating rod to form a normal solidifying agent layer.
(6) While performing the operation of (5), lift the excavation rod above the ground to complete the injection of the solidifying agent into the excavated hole.

In another method invention, a drilling head attached to the lower end of a drilling rod is used to drill a drilling hole, and a hardening agent is filled in the drilling hole as follows to form a high-strength solidifying agent layer and a normal solidifying agent layer in the drilling hole. A method of injecting a solidification agent into a borehole characterized by forming a layer of the solidification agent.
(1) The drilling rod has a hollow portion formed with one liquid passage, the drilling head is provided with a lower discharge port communicating with the liquid passage, and the upper portion of the drilling head communicates with the liquid passage and is normally closed. An upper discharge port was provided.
(2) When the excavation of the excavated hole is completed, a solidifying agent is injected from the lower discharge port into the lower end of the excavated hole to replace the excavated hole residue and the solidifying agent, or Stir to mix with the residue.
(3) While pulling up the excavation rod, the solidification agent is injected from the lower discharge port to a predetermined height of the previously set excavation hole to form a high-strength solidification agent layer.
(4) Subsequently, a switching piece is introduced from above the liquid path to release the closing of the upper discharge port, block the liquid path on the lower discharge port side, and discharge from the lower discharge port to the upper discharge port. switch exits.
(5) Injecting a solidifying agent into the excavated hole from the upper discharge port, and stirring the discharged solidifying agent with the residue in the pile hole while pulling up the excavating rod to form a normal solidifying agent layer.
(6) While performing the operation of (5), lift the excavation rod above the ground to complete the injection of the solidifying agent into the excavated hole.

Further, in the invention of each method described above, there is provided a method for injecting a solidifying agent into an excavated hole configured as follows.
(1) While pulling up the drilling rod as described above, the solidifying agent is injected from the lower outlet to a predetermined height of the drilled hole to form a high-strength solidifying agent layer, and the lower outlet is set in advance. When the set depth position is reached, the excavation rod is temporarily stopped from rising.
(2) Insert the switching piece as described above to close the lower discharge port and open the upper discharge port.
(3) Before, after, or at the same time as (2), the excavation rod is lowered or raised to position the upper discharge port near the set depth position, and while the solidifying agent is being discharged from the upper discharge port, the Lowering or raising the drilling rod.

Further, the invention of this rod is a drilling rod characterized by having a drilling head at its lower end and configured as follows.
(1) A liquid passage is formed in the hollow portion of the excavating rod for conveying the solidifying agent supplied from the solidifying agent supply device on the ground to the discharge port.
(2) A lower end of the liquid passage is connected to a lower discharge port formed in the drilling head.
(3) The excavation rod is provided with an upper discharge port at a height position above the excavation head, and the upper discharge port is connected through a branch portion formed in the liquid path.
(4) The upper outlet was closed with an upper outlet closing member.
(5) The liquid path can supply the switching tool from above toward the branch.
(6) When the switch reaches the branched portion, the switch can release the blockage of the upper discharge port by the closing member to open the upper discharge port and block the lower discharge port.

Further, in the rod invention, the excavation rod is configured as follows.
(1) The drilling rod was provided with a kneading drum above the drilling head for kneading the wall of the drilled hole, and an upper discharge port was formed immediately above the kneading drum.

Further, another rod invention is a drilling rod equipped with a drilling head at its lower end and configured as follows.
(1) A liquid passage is formed in the hollow portion of the excavating rod for conveying the solidifying agent supplied from the solidifying agent supply device on the ground to the discharge port.
(2) A lower end of the liquid passage is connected to a lower discharge port formed in the drilling head.
(3) The drilling rod is provided with a kneading drum for kneading the wall of the drilled hole at a height position above the drilling head, and an upper discharge port is formed immediately above the kneading drum.
(4) The upper discharge port was connected through a branch portion formed in the liquid passage.
(5) The upper outlet is closed by the closing member for the upper outlet, and a switching member is provided which can release the closure by the closing member to open the upper outlet and close the lower outlet.

The "high-strength solidifying agent layer" and "ordinary solidifying agent layer" described above have a solidifying strength of
"Normal solidifying agent layer"<"High strength solidifying agent layer"
It should be In general, the ratio of the amount of solidification agent, such as cement milk, with the same solidification strength (water-cement ratio, etc.) to the space for the solidification agent in the pile hole (the volume of the planned portion of the excavated hole) is called “normal solidification.” The "high-strength solidifying agent layer" is formed more often than the "agent layer". The "high-strength solidifying agent layer" and "ordinary solidifying agent layer" are formed by other methods, such as using solidifying agents with different solidifying strengths (such as the water-cement ratio) of the cement milk to be added. You can also

In the present invention, since the drilling rod is provided with the upper discharge port directly above the drilling head, after the drilling head has drilled the drilling hole, the solidifying agent introduced into the drilling hole from the upper discharge port is immediately stirred by the drilling head. , can form a high-quality solidifying agent layer. Furthermore, if a kneading drum is provided directly below the upper discharge port, the solidifying agent introduced into the excavated hole from the upper discharge port can be immediately stirred and kneaded by the kneading drum, so that a better quality solidifying agent layer can be formed. .

(a) is a front view of the drilling rod of the present invention, (b) is an enlarged longitudinal sectional view of part A of (a), and (c) is an enlarged longitudinal sectional view of part B of (b). (a) to (h) represent schematic longitudinal sectional views for explaining the construction method of the present invention. In the first embodiment showing the operation of the discharge switching part of the excavation rod of the present invention, (a) is a plan view and a longitudinal sectional view of a downward discharge state, (b) and (c) are longitudinal sectional views at the time of switching, (d) represents a vertical cross-sectional view of an upward ejection state. (a), (b), and (c) are partial enlarged views of (a), (b), and (c) in FIG. In the second embodiment showing the operation of the discharge switching part of the excavation rod of the present invention, (a) is a cross sectional view and an XYZ sectional view of the downward discharge state, and (b) and (c) are XYZ sectional views at the time of switching. and (d) is an XYZ cross-sectional view of an upward ejection state.

An embodiment of the present invention will be described based on the drawings.

1. Configuration of drilling rod 40

(1) A drilling rod 40 is constructed by connecting a drilling head 30 to the lower end of the rod body 1 (FIG. 1(a)). The rod body 1 is formed from a cylindrical body (pipe body) having a hollow portion.
The rod main body 1 is constructed by vertically connecting the required number of unit rods 3A, unit rods 3B, and unit rods 3C. A unit rod 3A of a standard portion, a unit rod 3B having an upper discharge port 6 and a branch portion 25 near the upper discharge port 6, and a unit rod having kneading drums 5, 5 attached to the outer circumference of the unit rod 3A of the standard portion. Prepare 3C. Each unit rod 3A, 3B, 3C has a liquid passage 2 formed in its hollow portion.

(2) The unit rod 3B is provided with a through-hole connected to the hollow portion (liquid path) in the outer wall as the upper discharge port 6, and is provided with a closed cylinder (closing member) 7 for closing the upper discharge port 6 (through-hole). The closed cylinder 7 is a cylindrical body having an outer diameter smaller than the inner diameter (2×R0) of the rod body 1, and upper and lower annular locking ribs are provided on the upper and lower sides of the outer periphery of the cylindrical body so as to be able to abut on the inner wall 1a of the rod body 1. 8 and 9 are provided. The upper annular rib 8 and the lower annular rib 9 are located above and below the upper discharge port 6 when closed, respectively, and cooperate with the outer wall surface of the closed cylinder 7 to block the liquid passage 2 and the upper discharge port 6. 1(b) and 1(c). Therefore, when the maximum outer diameter of the upper annular rib 8 and the lower annular rib 9 is "2 x R2", the maximum outer diameter of the closed cylinder 7 (2 x R2) < the inner diameter of the rod body 1 (2 x R0)
is formed by Also, the inner diameter of the closed cylinder 7 is assumed to be "2×R1".
When the upper discharge port 6 is closed, the closing cylinder 7 is engaged with the upper annular rib 8 of the closing cylinder 7 and the unit rod 3 is locked.
A locking tool 13 is provided on the inner wall of the unit rod 3B to keep it from falling inside B. The locking tools 13 are housed in a recess 11 formed in the inner wall of the unit rod 3B, and are biased inwardly by a spring 17. At least two of the locking tools 13 are provided at diametrically symmetrical positions. The locking tool 13 includes a lower locking claw (small projection) for locking the upper annular rib 8 of the closed cylinder 7 and an upper operation claw 14 having a large projection toward the center. and The upper operation claw 14 has an upper surface formed with an inclined surface having a downward slope toward the center (inward). At least two locking members 13, 13 may be provided diametrically symmetrical about the axis of the unit rod 3A (FIG. 1(c)), or three or more may be provided rotationally symmetrically (not shown). .

(3) A stopper 18 is protruded below the upper discharge port 6 from the inner wall of the unit rod 3B. The stopper 18 is provided at a position where the upper discharge port 6 is opened when the closed cylinder 7 is lowered when the locking of the locking member 13 is released (the closed cylinder 7 is closed when the lower end of the closed cylinder 7 hits the stopper 18). The upper end of the cylinder 7 is provided so as not to interfere with the upper discharge port 6), and is formed in a size that does not hinder the flow of the solidifying agent in the normal liquid passage 2 (Fig. 3(a)).

(4) The switching piece (switching tool) 20 has a planar circular large-diameter portion 21 (diameter 2×R3) formed at the top, tapered downward at a tapered side surface 22, and a small-diameter portion 23 formed at the bottom. configured. When the inner diameter of the unit rod 3A is (2×R0) and the inner diameter of the closed cylinder 20 is (2×R1), the maximum outer diameter of the large diameter portion 21 of the switching piece 20 is (2×R3). Radius (2 x R3)
<Inner diameter of unit rod 3A (2 x R0)
Inner diameter of closed cylinder 7 (2 x R1)
<Maximum radius of large diameter portion 21 (2 x R3)
It has become. That is, the switching piece 20 is formed so that it can move in the unit rod 3A with a gap, and the large-diameter portion 21 of the closing piece 20 can close the upper edge of the closing cylinder 7. As shown in FIG.
In addition, in a state in which the lower locking claw 16 is biased by the spring 17 and positioned inward to lock the lower edge of the upper annular rib 8 of the closed cylinder 7 (FIG. 1(c)), the unit rod is in a state of being locked. Assuming that the distance from the axis 10 of 3A to the inner edge 15 (inner tip) of the upper operating claw 14 is R4, the diameter of the circle passing through the inner edge 15 of each upper locking claw is "2×R4". At this time, if the radius R3 of the large diameter portion 21 of the switching piece 20 is
Diameter of circle passing through inner edge 15 of each upper locking pawl (2 x R4)
<Diameter of large diameter portion 21 of switching piece 20 (2 x R3)
It has become.
Also, the length (height) (L3) of the switching piece 20 is
Inside diameter (2R0) of unit rod 3A <Length (height) L3 of switching piece 20)
, and the large-diameter portion 21 is always positioned at the top when inserted into the unit rod 3A (FIG. 1(c)).
A branching portion 25 is a mechanism in which the switching piece 20 is combined with the upper discharge port 6 and the closing cylinder 7 . Therefore, in this embodiment, the positions of the branch portion 25 and the upper discharge port 6 are the same. (not shown).

(5) The excavation head 30 is configured by attaching swingable excavation arms 36, 36 to a head body 31, and forming a connecting portion 32 that connects the unit rods 3C (3A, 3B) to the upper end of the head body 31. There is. Further, movable digging blades 37, 37 are provided at the lower end of the digging arm 36, and fixed digging blades 33, 33 are provided at the lower end surface of the head body 31 (Fig. 1(a)).
Further, the connecting portion 32 is formed in the air, and forms a liquid passage 32a communicating with the liquid passage 2 of the rod body 1 (unit rods 3A, 3B, 3C). Furthermore, the liquid path 32 a of the connecting portion 32 communicates with the liquid path 35 in the head body 31 and reaches the lower discharge port 34 formed on the bottom surface of the head body 31 .
An opening/closing valve may be arranged in the lower discharge port 34, and when this valve is opened, the solidifying agent passing through the liquid paths 2, 32a, and 35 can be discharged out of the drilling head 30. .

(6) The unit rod 3C provided with the kneading drums 5, 5 is connected to the connecting portion 32 of the excavation head 30, and the unit rod 3B provided with the upper discharge port 6 is connected thereon. The standard unit rods 3A, 3A are connected to constitute the drilling rod 40 of the present invention (Fig. 1(a)).

2. Drilling method of pile hole

(1) A drilling rod 40 is attached to the drilling machine, in which the unit rod 3A, the unit rod 3B, the unit rod 3C, and the drilling head 30 (with the drilling arm 36 closed) are connected in this order. The upper discharge port 6 is closed by the closing cylinder 7 , and the liquid paths 2 , 32 a and 35 of the drilling rod 40 are opened at the lower discharge port 34 of the drilling head 40 .
An excavation rod 40 (excavator) is rotated to excavate a pile hole shaft portion 42 having a diameter D10 from the ground 41 (Fig. 2(a)). The excavation rod 40 is held on the ground 41, and while connecting the next unit rod 3A to the uppermost unit rod 3A, the length of the rod body 1 is lengthened in order, and the excavation rod 40 is drilled to a predetermined depth with a diameter D10. The pile hole shaft portion 42 is excavated (Fig. 2(b)). At this time, the drilling fluid (water) is discharged from the lower discharge port 34 of the drilling head 40 through the liquid paths 2, 32a, and 35 from the ground 41 if necessary.
Subsequently, the excavation arms 36, 36 are opened to set the diameter expansion mode, and the pile hole expanded bottom portion 43 is excavated with a diameter D20 (>D10) so as to expand the outer wall of the pile hole shaft portion 42 (Fig. 2(c)). .
When the excavation of the pile hole enlarged bottom portion 43 is completed (FIG. 2(c)), the material to be poured into the liquid path 2 is switched from the excavating liquid to the cement milk on the ground 41, and the excavating head 40 is moved to the pile. Positioned at the bottom 43a of the hole expanded bottom portion 43 (FIG. 2(c)), the foot protection liquid is supplied from the ground 41, the foot protection liquid is discharged from the lower discharge port 34 of the excavation head 40, and the pile hole expanded bottom portion The pile hole remnants (water, excavated soil, etc.) in 43 are replaced with foot protection liquid, and the excavation head 40 is positioned at the upper end of the enlarged pile hole bottom portion 43 (the lower end of the pile hole shaft portion 42), and the pile hole A foot hardening liquid layer (strength solidifying agent layer) 45 is formed in the enlarged bottom portion 43 (FIG. 2(d)). At this time, since the upper discharge port 6 is closed by the closed cylinder 7, the foot hardening liquid passes through the closed cylinder 7 at the branch portion 25 and is sent downward (FIG. 1(b), FIG. 3). (a)) and reaches the lower discharge port 34 .
note that. In this case, depending on the conditions at the construction site, the pile hole residue and the foot protection liquid can be agitated and mixed to form the soil cement.

(2) With the foot protection liquid layer 45 formed (FIG. 2(d)), the upper discharge port 6 is slightly (predetermined distance ) above (FIG. 2(d)).
Subsequently, once the excavating rod 40 is removed from the excavator (or removed from the uppermost unit rod 3A attached to the pile driver), the unit below it is removed so as to maintain the current depth ( height). The rod 3A portion is held on the ground 41. A switching piece 20 is inserted into the hollow portion (liquid path 2) of the unit rod 3A whose upper end is open. In this state, since the hollow portion (liquid path 2) of the unit rod 3A whose upper end is open is normally filled with the foot protection liquid, the switching piece floats or gently descends in the foot protection liquid. situation.
Then, the unit rod 3A whose upper end is open is again connected to the pile driver (or the uppermost unit rod 3A), the holding on the ground 41 is removed, and the upper discharge port 6 becomes the pile hole enlarged bottom portion 45 (foot protection The excavation rod 40 is once lowered so as to be positioned at the upper end 43b (the lower end 42a of the pile hole shaft portion 42) (Fig. 2(e)).
Here, in the state where the foot protection liquid layer 45 is formed (Fig. 2(d)), the upper discharge port 6 is substantially the same as the upper end 43b of the pile hole expanded bottom portion 43 (the lower end 42a of the pile hole shaft portion 42). or slightly below the upper end 43b (the lower end 42a of the pile hole shaft portion 42) (not shown). In this case, the following operation (3) is unnecessary, or the operation for descending and ascending is reversed.

(3) In the above (2), before inserting the switching piece 20, the excavation rod 40 is lowered so that the upper discharge port 6 reaches the upper end 43b (pile hole axis) of the enlarged pile hole bottom portion 45 (foot protection layer) It can also be positioned at the lower end 42a) of the portion 42 to hold the drilling rod 40 on the ground 41 (Fig. 2(e)). In this case, after the switching piece 20 is thrown into the unit rod 3A and the excavation rod 40 is released from the ground 41, the excavation rod 40 is immediately raised.

(4) Subsequently, the pile circumference fixing liquid (cement milk) is poured into the liquid path 2 from the ground 41 . Due to this flow of the pile circumference fixing liquid, the switching piece 20 above the liquid path 2 is swept downward and descends above the closing tube 7 (FIGS. 3(b) and 4(a)). Subsequently, the upper end portion of the tapered side surface 22 and the large-diameter portion 21 of the switching piece 20 hit the upper operating claw 14 (inner edge 15) of the locking member 13, pushing the locking member 13 into the concave portion 11 against the spring 17. Push out. At the same time, the locking between the lower locking claw 16 of the locking device 13 and the upper annular rib 8 of the closing tube 7 is released (FIG. 4(b)). Therefore, the upper end portion of the tapered side surface 22 of the switching piece 20 and the large diameter portion 21 that continue to descend push the upper end of the closing cylinder 7 , and the closing cylinder 7 descends together with the switching piece 20 . The small-diameter portion 23 enters the closed tube 7, and the upper surface of the closed tube 7 is blocked by the upper end portion of the tapered side surface 22 and the large-diameter portion 21 (FIGS. 4(b) and 3(c)). Also, the tapered side surface 22 of the lowered switching piece 20 may come into contact with the lower locking claw 16 of the locking member 13 which is again urged inward (in the centripetal direction of the shaft 10) by the spring 17. However, since the tapered surface 22 pushes the lower locking claw 16 outward (in the radial direction from the shaft 10), the switching piece 20 descends beyond the lower locking claw 16 (FIG. 4(c)).
Further, the switching piece 20 and the closing cylinder 7 descend to open the upper discharge port 6 from the upper side (FIGS. 4(c) and 3(c)). When the lower end of the nozzle comes into contact with the stopper 18, the downward movement is stopped, and the upper discharge port is fully opened (Fig. 3(d)). Therefore, the pile circumference fixing liquid flowing through the liquid path 2 from above does not flow downward (to the side of the lower discharge port 34) because the hollow portion of the closing cylinder 7 is blocked by the switching piece 20. It is discharged from the upper discharge port 6 into the pile hole shaft portion 42 (FIGS. 2(e) and 3(d)).

(5) Since the upper discharge port 6 of the excavation rod 40 is positioned at the upper end 43b (lower end 42a of the pile hole shaft portion 42) of the pile hole enlarged bottom portion 43 (foot protection layer 45), the excavation rod 40 is rotated. , the discharged pile circumference fixing liquid is immediately agitated by the kneading drums 5, 5 of the unit rod 3C rising from below, and immediately flows into the pile holes on the outer peripheral surfaces of the kneading drums 5, 5. kneaded into the wall. The pile circumference fixing liquid (solidifying agent) injected from the upper discharge port 6 is also agitated by the excavation head 30 (partly kneaded into the pile hole wall by the excavation arms 36, 36). Therefore, the pile circumference fixing liquid is efficiently stirred and mixed with the pile hole residue and efficiently kneaded into the pile hole wall, so that a good quality foot protection liquid layer 46 (ordinary solidifying agent layer) can be formed (Fig. 2 ( f) (g)).

(6) If the excavation rod 40 is pulled up to the ground 41 in this operation, a hardening layer 45 and a fixed liquid layer 46 around the pile can be formed in the pile holes 42 and 43 (Fig. 2(h)).
Thereafter, prefabricated piles are embedded in the pile holes 42, 43 by conventional methods to construct the foundation piles (not shown).

(7) In the above embodiment, the solidification agent is cement milk with the same solidification strength (water-cement ratio, etc.), and the input amount is
Pile circumference fixing liquid<foot hardening liquid, but cement milk having a higher solidification strength (water-cement ratio, etc.) can also be used as the foot hardening liquid.
Further, in the above-described embodiment, the pile hole expanded bottom portion 43 is formed with the diameter D20, but it can also be formed with the same diameter D10 as the pile hole shaft portion 42 (not shown).
In the above embodiment, the method can also be applied to soft soil and the solidification agent can be used as a soil improvement agent. In this case, no prefabricated pile is embedded in the pile hole excavated to form the solidifying agent layer.

3. Other embodiments

(1) In the above embodiment, the unit rod 3C to which the kneading drums 5, 5 are attached may be further connected above the unit rod 3B (upper discharge port 6) to form the excavating rod 40 (not shown). not). That is, the kneading drum 5 is positioned above and below the upper discharge port 6 .
Further, in the above embodiment, the unit rod 3C to which the unit rod 3C to which the kneading drums 5, 5 are attached is omitted, and the unit rod 3B is connected directly above the excavation rod 30 to form the excavation rod 40. (not shown).
Also, in the above-described embodiment, a structure in which the unit rod 3B or the unit rod 3C is fixed to the drilling head 30 (not shown) can be employed. That is, the structure is such that the kneading drums 5 and 5 and the upper discharge port 6 are formed at the upper end of the head body 31 .

(2) In the above-described embodiment, the locking member 13 is arranged in the concave portion 11, and the flow of the liquid passage 2 of the unit rod 3A is directed downward (lower discharge port 34) by the closing cylinder 7 and the switching piece 20. Although the flow is switched to the side or to the upper discharge port 6b, another switching structure can be adopted (not shown).

(3) In the above-described embodiment, since the lower discharge port 34 is provided at the lower end of the head body 31, the hardening agent can be injected from the vicinity of the bottom 43a of the pile hole enlarged bottom portion 43 when forming the foot protection layer 45. Also, it is effective that the drilling fluid can be introduced in the vicinity of the drilling edges 33, 37, but it can also be provided at other positions of the drilling head 40 (not shown).

(4) In the above embodiment, the rod body 1 (unit rods 3A, 3B, 3C) is a single cylinder, but the rod body 1 (unit rods 3A, 3B, 3C) is replaced by a double cylinder consisting of the inner cylinder 51 and the outer cylinder 53. Unit rods 3A, 3B, 3C) can also be constructed (FIG. 5). In this case, different types of fluids can be injected into the pile hole at the same time or staggered times. Therefore, in this case, the inside of the inner tube 51 becomes the liquid path 2, and the outer wall of the inner tube 51 and the inner wall of the outer tube 53 constitute the liquid path 2a.
For example, in the unit rod 3A, the inner cylinder 51 and the outer cylinder 53 connect the through hole 52 of the inner cylinder 51 and the through hole 54 of the outer cylinder 53 with the connecting horizontal cylinder 55 to form the upper discharge port 56. There is (Fig. 5(a)). In this case, the single-cylinder unit rod 3A (FIG. 3(a)) is used as an inner cylinder 51, and is covered with an outer cylinder 53 having a through hole 54 formed thereon. Therefore, the inner cylinder 51 is provided with the closed cylinder 7 for closing the through hole 52 (upper discharge port 6) and the locking tool 13 for removing the closed cylinder 7 in the concave portion 11, as in the above-described embodiment. and a switching piece 20 for operating the locking member 13 are combined to form a switching structure (see FIG. 5, FIG. 1(c), and FIG. 4).
Therefore, in a normal state, the closed cylinder 7 is locked by the locking tool 13 (see FIG. 4(a)), the upper discharge port 56 (through hole 52) is blocked by the closed cylinder 7, and solidification through the liquid path 2 occurs. The agent passes through the hollow portion of the closed cylinder 7 and is introduced into the pile holes 42 and 43 from the lower discharge port 34 (Fig. 5(a)).
As in the above embodiment, when the switching piece 20 is inserted into the inner cylinder 51 (FIG. 5(b)), the locking of the locking member 13 to the closing cylinder 7 is released by the switching piece 20 (FIG. 4(b)). ) (c)), the closing cylinder 7 whose upper end is closed by the switching piece 20 falls downward (FIG. 5(c)), and when it abuts against the stopper 18, the through hole 52 is fully opened, and the communicating connection is established. The solidifying agent is discharged from the horizontal tube 55, the through hole 54, that is, the upper discharge port 56 (Fig. 5(d)).
The outer side of the upper discharge port 56 (the through hole 54 of the outer cylinder 53) is covered with a closing lid 57 so that it can be opened freely by the momentum of the solidifying agent discharged from the upper discharge port 56 (Fig. 5(c)(d)). In other words, it is installed to prevent backflow, and also prevents clogging of the upper discharge port 56 due to clogging of mud or the like when the upper discharge port 56 does not operate.

1 rod body 2 liquid passage 2a liquid passage 3A unit rod 3B unit rod (with upper discharge port)
3C unit rod (with kneading drum)
5 Kneaded Lamb
6 Upper discharge port 7 Closing tube (closing tool)
8 upper annular rib 9 of closing tube lower annular rib 11 recess 13 locking device 13 upper operating claw 14 of locking device inner edge 16 of upper operating claw of locking device lower locking device 18 stopper 20 Switching piece (switching tool)
21 large-diameter portion 22 of switching piece tapered side surface 23 of switching piece small-diameter portion 25 branching portion 30 excavation head 31 excavation head main body 32 connecting portion 32a of excavation head liquid passage 33 fixed excavation blade 34 of excavation head head)
35 Liquid path 36 Excavating arm of excavating head 37 Moving excavating blade of excavating head 40 Excavating rod 41 Ground surface 42 Pile hole shaft (drilling hole)
42a Lower end of pile hole shaft 43 Expanded bottom of pile hole (drilled hole)
43a bottom of enlarged pile hole bottom 43b upper end of enlarged pile hole bottom 45 foot hardening liquid layer (high-strength solidifying agent layer; first solidifying agent layer)
46 Pile perimeter fixing liquid layer (ordinary solidifying agent layer, second solidifying agent layer)
51 inner cylinder 52 inner cylinder through hole 53 outer cylinder 54 outer cylinder through hole 55 connecting horizontal cylinder 56 upper discharge port 57 open/close lid

Claims (6)

A drilling head equipped at the lower end of a drilling rod is used to drill a drilling hole, and a solidifying agent is filled in the drilling hole as follows to form a high-strength solidifying agent layer and a normal solidifying agent layer in the drilling hole. A method of injecting a solidifying agent into a drilled hole.
(1) The drilling rod is formed of a double cylinder consisting of an inner cylinder and an outer cylinder. Two liquid passages are formed, the drilling head is provided with a lower outlet communicating with the first liquid passage , and the drilling head is provided with an upper outlet communicating with the first liquid passage and normally closed. rice field.
(2) When the excavation of the excavated hole is completed, a solidifying agent is injected from the lower discharge port into the lower end of the excavated hole to replace the excavated hole residue and the solidifying agent, or Stir to mix with the residue.
(3) While pulling up the excavation rod, the solidification agent is injected from the lower discharge port to a predetermined height of the previously set excavation hole to form a high-strength solidification agent layer.
(4) Subsequently, a switching piece is introduced from above the first liquid passage to release the closure of the upper discharge port and close the liquid passage on the side of the lower discharge port, and the liquid passage from the lower discharge port to the upper discharge port. Switch the outlet to
(5) Injecting a solidifying agent into the excavated hole from the upper discharge port, and stirring the discharged solidifying agent with the residue in the pile hole while pulling up the excavating rod to form a normal solidifying agent layer.
(6) While performing the operation of (5), lift the excavation rod above the ground to complete the injection of the solidifying agent into the excavated hole. A drilling head equipped at the lower end of a drilling rod is used to drill a drilling hole, and a solidifying agent is filled in the drilling hole as follows to form a high-strength solidifying agent layer and a normal solidifying agent layer in the drilling hole. A method of injecting a solidifying agent into a drilled hole.
(1) The drilling rod has a hollow portion formed with one liquid passage, the drilling head is provided with a lower discharge port communicating with the liquid passage, and the upper portion of the drilling head communicates with the liquid passage and is normally closed. An upper discharge port was provided.
(2) When the excavation of the excavated hole is completed, a solidifying agent is injected from the lower discharge port into the lower end of the excavated hole to replace the excavated hole residue and the solidifying agent, or Stir to mix with the residue.
(3) While pulling up the excavation rod, the solidification agent is injected from the lower discharge port to a predetermined height of the previously set excavation hole to form a high-strength solidification agent layer.
(4) Subsequently, a switching piece is introduced from above the liquid path to release the closing of the upper discharge port, block the liquid path on the lower discharge port side, and discharge from the lower discharge port to the upper discharge port. switch exits.
(5) Injecting a solidifying agent into the excavated hole from the upper discharge port, and stirring the discharged solidifying agent with the residue in the pile hole while pulling up the excavating rod to form a normal solidifying agent layer.
(6) While performing the operation of (5), lift the excavation rod above the ground to complete the injection of the solidifying agent into the excavated hole. 3. A method of injecting a solidifying agent into a borehole according to claim 1 or claim 2, comprising the following.
(1) While pulling up the drilling rod as described above, the solidifying agent is injected from the lower outlet to a predetermined height of the drilled hole to form a high-strength solidifying agent layer, and the lower outlet is set in advance. When the set depth position is reached, the excavation rod is temporarily stopped from rising.
(2) Insert the switching piece as described above to close the lower discharge port and open the upper discharge port.
(3) Before, after, or at the same time as (2), the excavation rod is lowered or raised to position the upper discharge port near the set depth position, and while the solidifying agent is being discharged from the upper discharge port, the Lowering or raising the drilling rod. A drilling rod characterized by being equipped with a drilling head at its lower end and configured as follows.
(1) A liquid passage is formed in the hollow portion of the excavating rod for conveying the solidifying agent supplied from the solidifying agent supply device on the ground to the discharge port.
(2) A lower end of the liquid passage is connected to a lower discharge port formed in the drilling head.
(3) The excavation rod is provided with an upper discharge port at a height position above the excavation head, and the upper discharge port is connected through a branch portion formed in the liquid path.
(4) The upper outlet was closed with an upper outlet closing member.
(5) The liquid path can supply the switching tool from above toward the branch.
(6) When the switch reaches the branched portion, the switch can release the blockage of the upper discharge port by the closing member to open the upper discharge port and block the lower discharge port. 5. A drilling rod according to claim 4 , configured as follows.
(1) The drilling rod was provided with a kneading drum above the drilling head for kneading the wall of the drilled hole, and an upper discharge port was formed immediately above the kneading drum. A drilling rod characterized by being equipped with a drilling head at its lower end and configured as follows.
(1) A liquid passage is formed in the hollow portion of the excavating rod for conveying the solidifying agent supplied from the solidifying agent supply device on the ground to the discharge port.
(2) A lower end of the liquid passage is connected to a lower discharge port formed in the drilling head.
(3) The drilling rod is provided with a kneading drum for kneading the wall of the drilled hole at a height position above the drilling head, and an upper discharge port is formed immediately above the kneading drum.
(4) The upper discharge port was connected through a branch portion formed in the liquid passage.
(5) The upper outlet is closed by the closing member for the upper outlet, and a switching member is provided which can release the closure by the closing member to open the upper outlet and close the lower outlet.

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