JP3177409B2 - Construction method of double pipe double packer injection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical solution for drilling a ground and then injecting a solidifying material into the excavation hole to form consolidated soil, thereby reducing the permeability of the ground and strengthening the ground. In particular, the present invention relates to a double pipe double packer injection method using an outer injection pipe and an inner injection pipe with a double packer.

[0002]

2. Description of the Related Art One of the ground improvement methods for improving the properties of the ground is a chemical liquid injection method. The chemical injection method is performed by drilling the ground and injecting cement, bentonite, water glass, and other chemicals into the ground from the excavation hole, and various methods have been developed.

Among them, the double-pipe double-packer injection method has recently achieved a great deal of construction results because it can reliably improve the target ground layer and can be repeatedly injected. The double pipe double packer pouring method is to first drill a casing in the target ground, then build an outer pouring pipe with a pouring hole at a predetermined interval in the axial direction in the casing, and then solidify it at the tip. The injection inner tube with a double packer, which has a material ejection portion and has a packer provided vertically above and below the ejection portion, is inserted into the injection outer tube, and the injection inner tube is moved in the axial direction to thereby reduce the injection inner tube. This is a method in which the spouted part is made to coincide with the injection hole of the outer injection pipe, and the solidified material is injected into the ground at each step while sequentially stepping up from the innermost injection hole.

In this type of double-pipe double-packer injection method, in order to prevent collapse of the excavation hole wall, an outer injection pipe is inserted into a drilled casing rod installed in the ground, and then the casing rod is removed. The method of mounting the outer tube for injection is adopted. Therefore, as drilling methods, besides sand layers and gravel layers that can only be drilled by the double pipe drilling method, single pipe casing drilling using drill bits with open ends such as ring bits and metal crowns It is common to do.

However, this drilling method causes a so-called core clogging phenomenon in which the excavated soil is clogged in the rod tip depending on the target ground, and often makes drilling difficult or impossible. Therefore, such a ground has conventionally been dealt with by drilling a single pipe casing or a double pipe using a residual drilling bit such as a kronen bit or a lost bit.

(1) A single pipe casing drilling method using a residual drill bit is provided with a casing in which a residual drill bit such as a lost bit or a kronen bit is removably fitted at the tip. In drilling, excavation is performed by sequentially connecting the casings in the axial direction. (2) In the double pipe drilling method, an outer pipe with an outer bit such as a ring bit or a metal crown fixed to the tip, and an inner bit such as a button bit or a cross bit inserted into the outer pipe are fixed to the tip. And a sealed inner tube. When drilling, excavation is performed by connecting the outer pipe and the inner pipe.

[0007]

However, the above-mentioned (1) the method of drilling a single pipe using a residual drill bit and the method (2) of drilling a double pipe have the following problems. (1) 'By the way, in actual construction, for example, in the case of a sand layer or a gravel layer, it is sometimes necessary to slightly raise the casing and reversely rotate the casing to prevent jamming. However, in the casing single pipe drilling method using this kind of drill bit, since drilling can be performed in only one direction, a long time is required for drilling work. When inserting the outer tube into the casing, discard the drill bit. (Specifically, rotate the casing in the reverse direction and pull it up slightly to drop the drill bit, then insert the outer tube and solidify. The construction cost was high because the material was injected and the bit was buried.

(2) 'The double pipe drilling method has excellent excavation ability, but when drilling, the outer pipe and the inner pipe must be connected respectively. Also, when inserting the outer tube into the outer tube, the inner tube must be pulled out. Therefore, the connection work of the outer pipe and the inner pipe and the work of pulling up and releasing the inner pipe require a lot of labor and a long time, and the construction cost is increased. The present invention has been made in view of such a problem, and an object of the present invention is to provide a double pipe double packer injection method that can shorten the construction period, reduce the construction cost and reduce the construction labor. The point is to provide.

[0009]

SUMMARY OF THE INVENTION The gist of the present invention resides in that after drilling a ground, a solidified material is injected from the excavation hole to form consolidated soil, thereby reducing the permeability of the ground. And a double pipe double packer injection method for strengthening the ground together with (1) an axially connected casing pipe provided with an outer bit at a tip thereof, and a casing pipe inserted into the tip of the casing pipe. Further, a step of piercing the ground with an inner bit assembly in which the bite portion is provided at the rear end and the inner bit is non-detachably attached to the front end and installing the casing pipe in the ground,
(2) having a bite portion at the tip that can bite with the bite portion,
An inner bit lifting device having a rear end connected to a wire is inserted into the casing pipe, and is engaged with a bite portion of the inner bit assembly at a tip portion of the casing pipe, and the inner wire is pulled out. Withdrawing the inner bit assembly together with the bit; (3) setting up an injection outer tube having an injection hole capable of ejecting the solidified material at predetermined intervals in the axial direction in the casing pipe; and (4) (5) withdrawing a casing pipe from the drilling hole and leaving only the injection outer tube in the drilling hole; (5) filling a gap between the drilling hole and the injection outer tube with sleeve grout; A) a spout capable of spouting the solidified material is provided at the tip, and a dove that allows the obstruction between the spout and the inner surface of the injection outer tube to be closed. (7) inserting a solidified material injection inner tube having a packer into the injection outer tube; and (7) positioning a jetting portion of the solidified material injection inner tube at the injection hole, and placing the solidified material injection inner tube above and below the injection hole. After closing between the side surface and the inner side surface of the injection outer tube by the double packer, the solidified material transferred in the solidified material injection hose is jetted from the jetting portion, and injected into the ground from the injection hole. And a top case located at the tip of the casing pipe.
The projection (1) provided on a part of the casing (12) in the circumferential direction
2a) can be freely opened and closed in the radial direction,
A cylindrical inner tube forming the base of the assembly (20)
(21) Attached to the approximate center and located on the opposite side in the radial direction
And biased radially outward by the latch spring (28)
Press the side (27b) of the latch (27)
Movement for rotating the inner bit assembly (20)
Depending on the operation, the inner bit drills the ground, and the present invention resides in a double pipe double packer injection method. The gist of the invention according to claim 2 is that after drilling the ground, a solidified material is injected from the excavation hole to form consolidated soil,
A double pipe double packer injection method for reducing the water permeability of the ground and strengthening the ground, comprising: (1) an axially connected casing pipe provided with an outer bit at a tip thereof; and the casing pipe. The casing pipe is installed in the ground by drilling the ground with an inner bit assembly inserted at the tip of the inside, the bite part is provided at the rear end, and the inner bit is attached to the tip part so as not to fall off (2) inserting an inner bit lifting device having a bite portion to be biteable with the bite portion at the front end and a rear end portion connected to a wire into the casing pipe, and The inner bit together with the inner bit by pulling out the wire by engaging the bite of the inner bit assembly in the portion. A step withdraw the assembly,
(3) a step of installing an injection outer pipe having an injection hole capable of ejecting the solidified material in the casing pipe at predetermined intervals in the axial direction; and (4) pulling out the casing pipe from the drilling hole and performing the injection. (5) filling the gap between the drilling hole and the injection outer tube with sleeve grout, and (6) forming a tip capable of ejecting the solidified material at the tip. , And sandwiching the ejection portion,
Inserting the solidified material injection inner tube having a double packer capable of closing the inner surface of the outer tube for injection into the outer tube for injection, and (7) inserting the ejection portion of the inner tube for solidified material into the injection hole. After closing the space between the outer surface of the inner tube above and below the injection hole and the inner surface of the injection outer tube by the double packer, the solidified material transferred in the solidified material injection hose is injected from the injection unit, and a step of injecting into the ground from said injection hole, said casing pie
Circumferential direction of the top casing (12) located at the tip of the
The convex part (12a) provided in a part of the
At present, the base of the inner bit assembly (20) is
Attached to approximately the center of the tubular inner tube (21)
And the latch spring (2
Latch (27) biased radially outward by 8)
Press the side surface (27b) of the inner bit assembly.
By rotating the yellowtail (20), the inner
Bits resides in the construction method of the double tube double packer injection, characterized by drilling the ground. The gist of the invention according to claim 3 resides in the double pipe double packer injection construction method according to claim 1, wherein a hole is drilled while applying an impact force together with a rotational force to the casing pipe. The gist of the invention according to claim 4 is that the tubular inner tube (21) forms a base ,
At the base end side of the inner tube (21),
(22) is attached, and the occluded part (22) is
Male part (22a) on the end side, cross-shaped leg on the tip side
(22b) is formed, and the legs (22b) are spear pins.
According to (23), a spear holder that is a short tubular body
(24) attached to the bite (22) and the front
The spear holder (24) is attached to the inner tube (2
1) The inner bit assembly which does not block the base end side.
While spraying water from inside the assembly (20)
The method according to claim 1 or 3, wherein a hole is formed .

[0010]

The inner bit attached to the end of the casing can be pulled up only by pulling out the wire, so that the outer pipe can be erected in the casing immediately after the casing is drilled. On the other hand, when drilling,
Since the inner bit is mounted so as not to fall off, the inner bit can be rotated in both forward and reverse directions, and drilling can be performed efficiently. Further, by applying an impact to the casing together with the rotation, efficient drilling can be performed even in a sand layer or a gravel layer.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. First, the drilling device 1 used in the method of performing double-pipe double-packer injection according to the present embodiment will be described. As shown in FIG. 1, the drilling device 1 is for drilling a ground G in a vertical direction, and is roughly composed of a casing pipe 10 and an inner bit assembly 20 inserted therein and located on the distal end side. ing. In the present embodiment, the tip side refers to the side of the hole drilling direction (the direction indicated by a white arrow in FIGS. 1 and 2). In the figure, reference numeral 40 denotes an overshot, and reference numeral 50 denotes a wire. FIG. 1 is simplified for the sake of space.

As shown in FIG. 2, the casing pipe 10 includes a plurality of rods 11 connected in the axial direction, and a top casing 1 connected to the rods 11 and located at the tip.
2 is roughly constituted. The rod 11 is a cylindrical body in which a male screw is cut at a distal end and a female screw is cut at a base (ground surface) end.

The top casing 12 has an outer bit 13 screwed to the distal end and a female thread cut to the proximal end. The male screw of the rod 11 is screwed to this female screw, and the outer bit 13 is located on the distal end side. The inside diameter of the portion where the latch 27 comes into contact is larger than the inside diameter of the distal end of the rod 11, and a step 11a is formed. Further, as shown in FIGS. 2 and 3, a convex portion 12a is provided in a part of the circumferential direction so as to extend in the axial direction.

As shown in FIG. 2, the inner bit assembly 20 has a cylindrical inner tube 21 as a base. An inner bit 33 is screwed to the distal end side of the inner tube 21. A spear (occlusal portion) 22 is attached to the proximal end side of the inner tube 21. As shown in FIGS. 2 and 4, the spear 22 has a male part 22a (not shown in FIG. 4) on the base end side and a cross-shaped leg part 22b on the distal end side. The leg 22b is attached to a spear holder 24 by a spear pin 23. The spear holder 24 is a short tubular body.
A flange 24a protruding radially inward is formed on the proximal end, and a male screw is cut on the distal end. The spear holder 24 is attached to the latch holder 25.

As shown in FIGS. 2 and 5, the latch holder 25 is a substantially cylindrical body having two latch holding pieces 25a at the distal end side, and is provided with a base of the inner tube 21 (not shown in FIG. 5). The end outer surface is slidably covered in the axial direction. The two latching pieces 25a have the same shape, are curved with the same curvature as the cylindrical portion, and are spaced at a predetermined interval in the circumferential direction. A rectangular latch hole 25b is opened at a substantially central portion in the longitudinal direction of each latch holding piece 25a. A bolt hole 25c is formed in the base. This bolt hole 25c
The latch holder 25 is attached to the inner tube 21 by a pair of stopper bolts 26 (not shown in FIG. 5) which are provided on the opposite side in the radial direction.

The latch 27 is attached to the center of the inner tube 21 so as to be freely opened and closed in the radial direction. The two latches 27 are located on opposite sides in the radial direction as shown in FIG.
It is urged radially outward by a latch spring 28 (not shown in FIG. 3). Therefore, the latch holder 2
5 is attached to the inner tube 21,
The outer portion of the latch 27 in the radial direction is inserted into the latch hole 25b shown in FIGS.

At the proximal end of the inner tube 21,
As shown in FIG. 2, a spring push 32 is screwed. The spring push 32 is a short tubular body,
A flange 32a protruding radially outward is formed at the proximal end. The proximal end surface of the flange 32a is
The spear holder 24 is in contact with the front end surface. The flange 32a is pressed by a spring 31 interposed between the front end surface and the inner peripheral projection 25e of the latch holder 25. The spring 31 presses the spring push 32 toward the proximal end, and the latch holder 25 screwed to the spear holder 24 is in a state of being urged toward the distal end. In the figure, reference numerals 29 and 30 are O-rings.

Next, an overshot 40 (inner bit lifting device) for lifting the inner bit assembly 20 will be described. Overshot 40
Is connected to a wire 50 as shown in FIG. 6, and a spear latch 41 (occlusal portion) is provided at the tip.

The spear latch 41 has two latch pieces 42.
(The latch piece 42 indicated by a two-dot chain line on the right side of the paper is shown in an open state) is a washing scissors-like member rotatably connected by a spring pin 43 at a substantially central portion. The distal end side is formed in a shape that can bite the spear 22. The proximal end is urged by a latch spring 45 so that the distal end is closed. The spear latch 41 is connected to a latch out ring 46 by another spring pin 44. The latch out ring 46 is connected to a pipe 48 via a hanger shaft 47. A cap 49 is screwed on the proximal end of the pipe 48.

Next, the operation of the drilling apparatus 1 configured as described above will be described with reference to FIGS. 7 to 9 are partial sectional views. The latch 27 is depicted on its side. When excavating, as shown in FIG.
Step 11a of rod 11 is free end 27a of latch 27
, The rod 11 pushes the inner bit assembly 20. At the same time, the protruding portion 12a of the top casing 12 shown in FIG. 3 presses the side surface 27b of the latch 27 to rotate the inner bit assembly 20.
By these operations, the inner bit 33 (not shown in FIGS. 7 to 9) can drill the ground (the casing pipe 10 itself including the rod 11 is rotated by a drilling machine installed on the ground surface, Digging). As a result, the ground can be drilled by the inner bit 33 together with the outer bit 13 (not shown in FIGS. 7 to 9). As the outer bit 13, an existing ring bit, metal crown, or the like can be used. In addition, as the inner bit 33, a cross bit, a button bit, or the like used for ordinary double pipe drilling can be used.

The overshot 40 (not shown in FIGS. 7 to 9) connected to the wire 50 is lowered into the casing pipe 10, and the spear latch 41 urged inward in the radial direction is connected to the spear 22 shown in FIG. When it abuts, it opens along its shape and engages the spear 22 as shown in FIG.

When the wire 50 is wound up with the spear latch 41 engaged with the spear 22, the latch holder 2
5 slides to the proximal end side, and the inner end surface 25d also shown in FIG. When the wire 50 is further wound, as shown in FIG.
5d presses the latch 27 to close it. When the wire 50 is further wound up, the front end surface 25f shown in FIG. Further wire 50
, The inner bit assembly 20 can be pulled up.

Next, a method of performing double-pipe double-packer injection using the drilling device 1 will be described with reference to FIGS. First, as shown in FIG. 10, the ground G is drilled by the drilling device 1 to a predetermined depth. After the drilling is completed, as shown in FIG.
0 raises the inner bit assembly 20.
Next, sleeve grout g is injected into the casing pipe 10 as shown in FIG. Sleeve grout g
Is to close the gap between the excavation hole C and the manchette tube 60 and to prevent the solidified material ejected from each injection hole 61 from escaping out of the target injection region. Cement bentonite (hereinafter referred to as CB) is used as the sleeve grout material.
Called wood. ).

Next, as shown in FIG. 13, the manchette tube 60 is erected in the casing pipe 10 filled with the sleeve grout g, and the casing pipe 10 is pulled out. An injection hole 61 is formed in the manchette tube 60 at a predetermined interval in the axial direction, and an elastic sleeve 62 that covers the injection hole 61 is mounted. As shown in the figure, a solidified material injection inner pipe 70 having a spout 72 for spouting the solidified material formed at the front end and a double packer 71 mounted at a position sandwiching the spout 72 is connected to a manchette tube. 60, and a CB material is injected into the ground G as a primary injection material. At this time, as shown in FIG. 14, the inside of the manchette tube 60 has a double packer 7 above and below the injection hole 61 located at the target injection position.
The solidified material, which has been closed by the inside of the solidified material injection inner tube 70, is ejected from the ejection portion 72, passes through the injection hole 61 of the manchette tube 60, and expands the elastic sleeve 62 while spreading the elastic sleeve 62. Is injected into. Such injection is performed sequentially from the deepest injection hole 61 to the shallowest injection hole 61. In the figure, the symbol f is the ground G
Refers to the CB material injected into it.

Next, as shown in FIG. 15, after the primary injection is completed, a low-viscosity water glass type solution having excellent permeability as a secondary injection material is similarly injected into the ground G to form consolidated soil. I do. Such injection is also performed sequentially from the deepest injection hole 61 to the shallowest injection hole 61 as shown in FIG. In the figure, the symbol s indicates a water glass-based solution type chemical injected into the ground G.

In the above description, a typical method for filling the sleeve grout g is shown. However, the present invention is not limited to this method.
A method of filling the inside of the casing pipe 10 after the manchette tube 60 is installed in the hole or a method of filling the excavation hole C after the casing pipe 10 is pulled out may be used.

Next, the effect of this embodiment will be described.
Overshot 40 attached to the tip of wire 50
Is engaged with the inner bit assembly 20 and the wire 50 is wound up, whereby the inner bit assembly 20 can be quickly pulled up. Therefore,
As in the case of using the conventional double pipe drilling method, it is not necessary to pull up the inner pipe or cut off the threaded portion, and it is possible to build the injection outer pipe into the casing immediately after drilling in the casing. Therefore, the construction labor is reduced,
Also, the construction period can be shortened. At the time of drilling, the inner bit 33 is fixed to the top casing and can rotate in both forward and reverse directions, so that drilling efficiency can be improved. Further, the inner bit 33 screwed to the tip of the inner tube 21 can be recovered by the overshot 40 without being buried and buried in the ground, which is economical. As a result, the construction period can be shortened and the construction cost can be reduced. In the construction experiment, it depends on the target ground and the drilling method.
/ 3 to 1/2. According to trial calculations based on the experimental results, the construction cost was generally less than 2/3 of the conventional cost.

As the solidifying material to be poured, a cement-based solidifying material, cement bentonite, water glass type, polymer type, non-chemical type, a mixture thereof and the like, which are suitable for carrying out the present invention, are employed. be able to. Further, in this embodiment, the method is employed for the injection of the soletanche. However, the method can be adopted for a method suitable for carrying out the present invention, such as a sleeve method or a double strainer injection method.

Further, in this embodiment, the case of drilling in the vertical direction is used, but the present invention can also be used in the case of drilling in the horizontal and oblique directions. In such a case, the insertion of the overshot 40 into the casing pipe 10 is as follows.
It may be performed using water pressure or the like. Also, when drilling,
Drilling can be performed while spraying water from the inside of the inner bit assembly 20 to the drilling surface. Such water discharge is possible because the spear 22 and the spear holder 24 do not block the base end side of the inner tube 21 as shown in FIGS. It is also possible to drill while adding percussion.

Further, the rod 11, the top casing 1
2. The length, diameter and shape of the inner bit assembly 20 may be suitable for practicing the present invention unless otherwise specified. In this embodiment, the spear (occlusal portion) 22 is provided on the inner bit assembly 20 and the spear latch (occlusal portion) 41 is provided on the overshot 40. However, in the present invention, the occlusion portion is provided on the inner bit assembly 20. In addition, an occluded portion may be provided on the overshot 40.

Further, the bite portion and bite portion are not limited to the present embodiment, and any structure may be used in the present invention as long as they can bite each other. In the above figure, the same components are denoted by the same reference numerals.

[0032]

Since the present invention is constructed as described above, the inner bit attached to the end of the casing can be pulled up only by pulling out the wire. Can be included. On the other hand, at the time of drilling, the inner bit is attached to the front end of the casing so as not to fall off, so that the inner bit can be rotated in both forward and reverse directions, and drilling can be performed efficiently. Further, by applying an impact force to the casing together with the rotational force, it is possible to efficiently drill holes even in a sand layer or a gravel layer. As a result, according to the present invention, the construction period can be shortened, the construction cost can be reduced, and the construction labor can be reduced.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view of a drilling apparatus according to the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 3;

FIG. 3 is a sectional view taken along line BB of FIG. 2;

FIG. 4 is a sectional view taken along the line CC of FIG. 2;

FIG. 5 is a perspective view of a latch holder.

FIG. 6 is a side view of an overshot.

FIG. 7 is a view showing the operation of the drilling device.

FIG. 8 is a diagram showing the operation of the drilling device.

FIG. 9 is a diagram showing the operation of the drilling device.

FIG. 10 is a process chart of a construction method of a double pipe double packer injection.

FIG. 11 is a process chart of a double pipe double packer injection method.

FIG. 12 is a process chart of a construction method of a double pipe double packer injection.

FIG. 13 is a process chart of a construction method of a double pipe double packer injection.

FIG. 14 is a process chart of a construction method of a double pipe double packer injection.

FIG. 15 is a process chart of a construction method of double pipe double packer injection.

FIG. 16 is a process chart of a double pipe double packer injection method.

[Explanation of symbols]

 G Ground C Drilling hole g Sleeve grout f Cement bentonite s Water glass solution type chemical 1 Drilling device 10 Casing pipe 11 Rod 11a Stepped portion 12 Top casing 12a Convex portion 13 Outer bit 20 Inner bit assembly 21 Inner tube 22 Spear 22a Male Part 22b Leg 23 Spear pin 24 Spear holder 24a Flange 25 Latch holder 25a Latch clipping piece 25b Latch hole 25c Bolt hole 25d Inner end face 25e Inner peripheral convex part 25f Tip end face 26 Stopper bolt 27 Latch 27a Free end 27c Side face 27c Side face 27c Latch spring 29, 30 O-ring 31 Spring 32 Spring push 32a Flange 33 Inner bit 34 Water channel 40 Overshot 41 Spear Pitch 42 latch piece 43, 44 spring pin 45 the latch spring 46 latches out ring 47 hanger shaft 48 pipe 49 cap 50 wire 60 Manchette tube 61 the injection hole 62 sleeve 70 and solidified material injection hose 71 double packer 72 ejection part

Continuation of the front page (56) References JP-A-3-199520 (JP, A) JP-A-6-341132 (JP, A) JP-A-6-158636 (JP, A) JP-A-3-36024 (JP) , U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) E02D 3/12

Claims (4)

(57) [Claims] 1. A method for injecting a double-pipe double packer for digging a ground, injecting a solidifying material from the digging hole to form consolidated soil, reducing the permeability of the ground and strengthening the ground. (1) An axially connected casing pipe having an outer bit provided at a tip thereof, an occluded portion inserted at a tip portion of the casing pipe provided at a rear end portion, and Drilling the ground with an inner bit assembly in which the bit is not detachably attached to the tip and installing the casing pipe in the ground; and (2) a bite portion that can bite with the bite portion at the tip. Have
An inner bit lifting device having a rear end connected to a wire is inserted into the casing pipe, and is engaged with a bite portion of the inner bit assembly at a tip portion of the casing pipe, and the inner wire is pulled out. (3) a step of raising the inner bit assembly together with the bit; (3) a step of setting up an injection outer pipe having an injection hole capable of ejecting the solidified material at predetermined intervals in the axial direction in the casing pipe; Withdrawing a casing pipe from the drilling hole and leaving only the injection outer tube in the drilling hole; (5) filling a gap between the drilling hole and the injection outer tube with sleeve grout; A) a spouting portion capable of spouting the solidified material is provided at the tip, and a gap between the spouting portion and the inner surface of the injection outer tube can be closed. Inserting a solidified material injection inner tube having a bullpacker into the injection outer tube; and (7) positioning a spout of the solidified material injection inner tube at the injection hole, and positioning the inner tube above and below the injection hole. After closing between the outer surface and the inner surface of the injection outer tube by the double packer, the solidified material transferred in the solidified material injection hose is jetted from the jetting portion, and injected into the ground from the injection hole. And a top casing which is located at a tip of the casing pipe.
(12a) provided on a part of the lug (12) in the circumferential direction
The inner bit assemble can be freely opened and closed in the radial direction.
Cylindrical inner tube (2)
1) is attached to the approximate center, located on the opposite side in the radial direction,
Biased radially outward by the latch spring (28)
Press the side surface (27b) of the latch (27)
For the operation of rotating the inner bit assembly (20)
Therefore, the inner bit drills the ground, and the double-pipe double-packer injection method is performed. 2. A method of injecting a double-pipe double packer for digging a ground, injecting a solidifying material from the digging hole to form consolidated soil, thereby reducing the water permeability of the ground and strengthening the ground. (1) An axially connected casing pipe provided with an outer bit at a tip thereof, and a bite portion provided at a rear end portion of the casing pipe inserted at a tip portion in the casing pipe, and an inner bit is provided. Drilling the ground with an inner bit assembly non-detachably attached to the tip to install the casing pipe in the ground; and (2) having a bite at the tip that can bite the bite. And
An inner bit lifting device having a rear end connected to a wire is inserted into the casing pipe, is engaged with a bite portion of the inner bit assembly at the tip of the casing pipe, and the inner bit is pulled out by pulling out the wire. Withdrawing the inner bit assembly together; (3) setting up an injection outer pipe having an injection hole capable of ejecting a solidified material at predetermined intervals in the axial direction in the casing pipe; and (4) casing. Withdrawing a pipe from the borehole and leaving only the outer fill pipe in the borehole; (5) filling a gap between the borehole and the outer fillhole with sleeve grout; (6) A spout that is capable of ejecting a solidified material is provided at the tip, and a dub that allows the gap between the spout and the inner surface of the outer injection tube to be closed. (7) inserting a solidified material injection inner tube having a lupacker into the injection outer tube; and (7) positioning a spouting portion of the solidified material injection inner tube at the injection hole, and arranging the inner tube above and below the injection hole. After closing between the side surface and the inner side surface of the injection outer tube by the double packer, the solidified material transferred in the solidified material injection hose is jetted from the jetting portion, and injected into the ground from the injection hole. And a top casing, which is located at a tip of the casing pipe.
(12a) provided on a part of the lug (12) in the circumferential direction
The inner bit assemble can be freely opened and closed in the radial direction.
Cylindrical inner tube (2)
1) is attached to the approximate center, located on the opposite side in the radial direction,
Biased radially outward by the latch spring (28)
Press the side surface (27b) of the latch (27)
For the operation of rotating the inner bit assembly (20)
Therefore, the inner bit drills the ground, and the double-pipe double-packer injection method is performed. 3. The method of claim 1, wherein the casing pipe is drilled while applying an impact force together with a rotational force to the casing pipe. 4. The substrate according to claim 1 , wherein said inner tube is a base.
And a proximal end of the inner tube (21)
The occlusal part (22) is attached, and the occlusal part (2 ) is attached.
2) is a male part (22a) at the base end and a cross at the tip end
A leg-shaped leg (22b) is formed, and the leg (22b) is
A spiaho which is a short tubular body is formed by a pier pin (23).
The occlusal part (22) is attached to the rudder (24).
And the spear holder (24) is an inner tube.
(21) The inner bit of which the base end side is not closed.
While spraying water from inside the assembly (20) to the drilled surface
The method according to claim 1 or 3, wherein the hole is drilled from the hole .