Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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DESCRIPTION
METHOD FOR IMPROVING GROUND
TECHNICAL FIELD
[0001]
The present invention relates to a technology of
improving ground which forms an underground consolidated body
by cutting a ground to be improved by injecting a cutting fluid
thereto, feeding a solidification material, mixing a cut ground,
the cutting fluid and the solidification material and agitating
a mixture thereof.
BACKGROUND
[0002]
One example of a method for improving ground in prior art
(e.g. Patent Document 1) will be described hereinafter with
reference to Fig. 8.
In Fig. 8, a rod-shaped jet device 11 is inserted into
a drilling hole HD drilled in a ground G to be improved. The
jet device 11 is provided with inject nozzles N for injecting
a cutting fluid jet J to a side face in order to inject a jet
flow of a cutting fluid (J: a cutting fluid jet) such as
high-pressure water to an underground G. A plurality of inject
nozzles N are provided at a point symmetrical with respect to
a central axis CL of the jet device 11 (e.g. two inject nozzles
shown in Fig. 8), and positions in a vertical direction of a
plurality of the inject nozzles N (positions in upward and
downward directions in Figs. 8 and 11) are the same.
The jet device 11 is provided with a flow passage for a
cutting fluid (a pipe for a cutting fluid: not shown) inside
thereof. A cutting fluid is fed from a feed device provided
above the ground (not shown) to the flow passage for a cutting
fluid in the jet device 11. The cutting
fluid is injected as
a cutting fluid jet J from the inject nozzles N in an outward
radial direction (in a horizontal direction).
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[0003]
In Fig. 8, the jet device 11 is slowly pulled up above
the ground (in an upward direction in Fig. 8) by injecting the
cutting fluid jet J underground and rotating the jet device 11
in e.g. an arrowed direction R. Accordingly, the ground G is
cut by the cutting fluid jet J, and an in-situ soil and the
cutting fluid are mixed to forma diameter-expanded cutting hole
HC having an inner wall surface W.
Meanwhile, a solidification material (e.g. cement) is
delivered from a discharge port (not shown) provided around a
lower end portion of the jet device 11 via a solidification
material flow passage (not shown) in the jet device 11.
Accordingly, the solidification material is mixed with a cut
in-situ soil to form an underground consolidated body (not
shown) by delivering the solidification material to said
diameter-expanded cutting hole HC. Herein, cases where the
solidification material is injected in an outward radial
direction like the cutting fluid jet J or together therewith
are considered as an example.
When the cutting fluid jet J cuts the ground G, slime is
generated as a mixture of the cut in-situ soil and the cutting
fluid. The slime, as
shown in an arrowed direction AD, is
discharged above the ground through a space S (a circular space)
between the jet device 11 and an inner wall surface of the
drilling hole HD.
[0004]
Fig. 9 shows all flow lines of the cutting fluid jet J
when the jet device 11 is pulled up by rotating the same a
plurality of times on the same cross section in the ground G
cut by the cutting fluid jet J. As shown in Fig. 9, all the
flow lines of the cutting fluid jet J are expressed as a plurality
of lines L extending parallel to each other at a predetermined
interval of P/2 (P is a pitch defined as the amount of pulling
up the jet device 11 while it is rotated one time). In Fig.
9, since the cutting fluid jet J is injected from two nozzles
N, the interval of flow lines of the cutting fluid jet J is 1/2
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of the pitch P.
In Fig. 9, an in-situ soil (ground, bedrock, rock, etc.)
found in a plurality of cutting fluid jets J extending parallel
to each other at a predetermined interval (1/2 of pitch P) is
cut by the jet J, the cut in-situ soil is mixed with a cut fluid
and discharged above the ground as slime.
[0005]
However, since the jet J is not injected to a region
between a plurality of the cutting fluid jets J (at an interval
of P/2), as shown in Fig. 10, a clod M whose representative size
is large (the biggest size out of a size in a longitudinal
direction, a size in a lateral direction and a size in an
elevational direction) is not cut and remains in a region
between a plurality of jets J ejected parallel to each other.
If the large clod M is not cut and remains in the ground,
as shown in Fig. 11, it is difficult for the large clod M to
pass a gap S (a circular space) between an inner wall surface
of a drilling hole HD and the jet device 11. Accordingly,
blocking of the gap S (the circular space) will prevent slime
from being discharged above the ground.
Therefore, in the above described method for improving
ground, a technology for preventing cutting of a clod M whose
representative size is large to remain in the ground is being
desired. Unfortunately, such a technology (a technology for
preventing cutting of a clod M whose representative size is
large to remain in the ground) has not been proposed yet.
PRIOR ART DOCUMENTS
PATENT DOCUMENTS
[0006]
Patent Document 1: JP-A-7-76821
SUMMARY OF THE INVENTION
PROBLEM TO BE SOLVED BY THE INVENTION
[0007]
The present invention was made in view of the above
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situation, and has an object to provide a method for improving
ground capable of preventing a clod whose representative size
is large from remaining in the ground.
MEANS FOR SOLVING THE PROBLEM
[0008]
The method for improving ground of the present invention
comprises the steps of: cutting a ground by injecting a cutting
fluid (e.g. high-pressure water or high-pressure air: including
a case where a solidification material is injected) from jet
devices (1, 10) ; feeding a solidification material; mixing a
cut ground (0), the cutting fluid and the solidification
material; and agitating a mixture thereof to form an underground
consolidated body, wherein a plurality of nozzles (Ni, N2) are
located at an interval in a vertical direction in the jet devices
(1, 10) , and when the cutting fluid is injected, a cutting fluid
(a cutting fluid jet J1) is injected from an upward nozzle (Ni)
in a downward skewed direction, and a cutting fluid (a cutting
fluid jet J2) is injected from a downward nozzle (N2) in an upward
skewed direction.
[0009]
The method for improving ground according to the present
invention preferably comprises a step of adjusting the angle
of the nozzles (Ni, N2) (e: the inject angle of jets J1 and J2) .
In addition, the method for improving ground of the
present invention preferably comprises a step of adjusting the
interval V between the nozzles (Ni, N2) in a vertical direction.
[0010]
In the present invention, it is preferable that a
partition forming material (jets J1, J2) is injected from an
upward direction of the jet device (10) as a cutting fluid, and
a solidification material (jets J3, J4) is injected from a
downward direction of the jet device (10) .
EFFECT OF THE INVENTION
[0011]
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The method for improving ground of the present invention
comprising the above steps can provide a construction in which
a plurality of nozzles (N1, N2) are located at an interval in
a vertical direction, a cutting fluid (jet J1) is injected from
the upward nozzle (N1) in a downward skewed direction and a
cutting fluid (jet J2) is injected from the downward nozzle (N2)
in an upward skewed direction. Accordingly, the method for
improving ground can provide a shape for flow lines of cutting
fluids (jets Jl, J2) injected for a certain period of time on
a plane at an optional position (Figs. 2 and 9: a plane containing
a central axis CL of a jet device 1 and extending in a radial
direction and a vertical direction: found in all directions at
3600 degrees with respect to the central axis CL of the jet device
1) so that a plurality of straight lines (J1, J2) parallel to
each other extending in a skewed direction intersect each other.
Therefore, even if a region (a clod G) which cannot be
cut by a cutting fluid jet (J) is found instantaneously, the
clod (G) is thereafter cut by another cutting fluid jet (a jet
Jl or J2). In other
words, even if a large clod (G) remains
in the ground after it cannot be cut by a cutting fluid jet (a
jet J1 or J2) instantaneously, the clod (G) is assuredly cut
by any flow line of a cutting fluid jet (a jet J1 or J2).
[0012]
Thus, according to the present invention, an extensive
presence of a region (a clod G) which is not cut by jet flows
(jets J) of a cutting fluid is prevented. Also, the method
for improving ground of the present invention prevents a clod
(G) whose representative size is large from extending parallel
to flow lines of the jet flow (the jets J) of the cutting fluid
and remaining in the ground, and it is possible to prevent a
region (a clod M) which is not cut by a cutting fluid jet (J)
from becoming too large (i.e. prevent the representative size
from becoming too large).
Accordingly, the maximum size of the clod (M) which is
not cut to remain in the ground becomes smaller and readily
passes a gap S (a circular space) between a jet device (1) and
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an inner wall surface of a drilling hole (HD). Specifically,
this means that the maximum size of the clod (M) which is not
cut to remain in the ground does not prevent slime from being
discharged above the ground.
[0013]
In a case that the method for improving ground of the
present invention is constructed so as to make the angle of
nozzles (Ni, N2) (9: the inject angle of jets Jl and J2) is
adjustable, it is possible to cut a construction ground (G) by
using an efficient cutting diameter (D) according to the type
of soil on the construction ground (G).
In the present invention, in a case it is constructed that
the interval (V) in a vertical direction between the nozzles
(Ni, N2) is adjustable, it is possible to adjust a pitch (P)
between flow lines of a jet flow (J) of a cutting fluid, and
it is thus possible to adjust the maximum size of the clod (M)
which is not cut by the jet flow (J) of the cutting fluid to
remain in the ground according to the state of a construction
site.
[0014]
In the present invention, a partition forming material
(jets J1, J2) is injected from an upward nozzle of a jet device
(10) as a cutting fluid, and a solidification material (jets
J3, J4) is injected from a downward nozzle of the jet device
(10). Accordingly, a layer of the partition forming material
(a separation layer LD) obtained by mixing the partition forming
material and a cut in-situ soil is formed upward, and a layer
of the solidification material (LC) obtained by mixing the
partition forming material, the cut in-situ soil and the
solidification material is formed downward.
Thus, only a mixture of the partition forming material
and the soil in the separation layer (LD) composed of the
partition forming material is discharged above the ground as
slime (a mixture of the partition forming material and the cut
soil), and a rich-mixed solidification material in the layer
of the solidification material (LC) is hardly discharged above
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the ground. Since the
solidification material is not
discharged above the ground, waste of a solidification material
is reduced and the amount of slime to be treated as an industrial
waste in a dedicated plant is reduced.
Also, since the solidification material (jets J3 and J4)
is injected from the downward nozzle of the jet device (10),
a mixture of the in-situ soil (clay) and the partition forming
material is favorably mixed with the solidification material,
even if the viscosity of the in-situ soil (e.g. clay) is high.
BRIEF DESCRIPTION OF DRAWINGS
[0015]
Fig. 1 is a schematic view showing a first embodiment of
the present invention;
Fig. 2 is a schematic view showing the state in which a
ground is cut by the first embodiment;
Fig. 3 is a schematic view showing an example of a
structure for adjusting the inject angle of a nozzle in the first
embodiment;
Fig. 4 is a schematic view showing an example different
from a structure for adjusting the inject angle of a nozzle in
the first embodiment shown in Fig. 3;
Fig. 5 is a schematic view showing one example of a
structure for adjusting the interval of a nozzle in the first
embodiment;
Fig. 6 is a schematic view showing an example different
from a structure for adjusting the interval of a nozzle in the
first embodiment shown in Fig. 5;
Fig. 7 is a schematic view showing a second embodiment
of the present invention;
Fig. 8 is a schematic view showing a method for improving
ground in prior art;
Fig. 9 is a schematic view showing the state in which a
ground is cut by the method for improving ground in prior art;
Fig. 10 is a schematic view showing one example of a cut
clod by the method for improving ground in prior art; and
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Fig. 11 is a schematic view showing a problem in the method
for improving ground in prior art.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016]
An embodiment of the present invention will be described
hereinafter, with reference to drawings of Figs. I to 7.
First, a first embodiment of the present invention will
be described with reference to Figs. 1 to 6.
In a prior art shown in Figs. 8 and 11, a pair of nozzles
N have a common position in a vertical direction (in upward and
downward directions in Figs. Sand 11 ) , and a cutting fluid (e.g.
high-pressure water: a jet flow (a cutting fluid jet J) that
can contain a solidification material) is injected in a
horizontal direction.
Meanwhile, according to an embodiment shown in Figs. 1
to 6, the positions of nozzles N1, N2 in a vertical direction
(in upward and downward directions in Fig. 1) are different,
and a cutting fluid jet J is injected in a skewed direction with
respect to a horizontal direction.
[0017]
In Fig. 1, a rod-shaped jet device I for injecting a jet
flow J (a cutting fluid jet) of a cutting fluid (e.g.
high-pressure water) is inserted into a drilling hole HD drilled
in a ground G to be improved.
The jet device 1 is provided with nozzles NI and N2 on
a side face thereof, and cutting fluid jets Jl, J2 are injected
from the nozzles N1 and N2. In this
description, the jets JI
and J2 are collectively referred to as a jet J.
The nozzles NI and N2 are disposed at an interval V in
a vertical direction (in upward and downward directions in Fig.
1).
In Fig. 1, a symbol CL represents a central axis of a jet
device 1.
[0018]
The cutting fluid jet Jl is injected from the upward nozzle
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Ni in a downward skewed direction relative to a horizontal
direction, and a inject direction of the cutting fluid jet Jl
is downward inclined by an angle 0 with respect to a horizontal
direction HO. The horizontal
direction HO is a direction
vertically extending with respect to a central axis CL of the
jet device 1.
On the other hand, the cutting fluid jet J2 is injected
from the downward nozzle N2 in an upward direction relative to
the horizontal direction, and a inject direction of the cutting
fluid jet J2 is upward inclined by an angle 0 with respect to
the horizontal direction HO.
In Fig. 1, a symbol D represents a cutting diameter of
a region (a cutting hole HC) cut by jets J1 and J2, and the cut
diameter of the cutting hole HC (the distance between the
central axis CL of the jet device 1 and an inner wall of the
cutting hole HC) is D/2.
[0019]
It is possible to employ a known device for the jet device
1, and a cutting fluid is introduced from a feed device (not
shown) provided above the ground to the jet device 1, and flows
through a flow passage for a cutting fluid (not shown) in the
jet device 1, and cutting fluid jets J1 and J2 are injected from
the nozzles Ni and N2 in an outward radial direction
(underground).
The jet device 1 injects the cutting fluid jets J1 and
J2 to cut a ground G, and is rotated as shown in an arrowed
direction R and pulled up toward a ground surface (upward in
Fig. 1: in an arrowed direction U).
The amount of pulling up the jet device 1 (the amount of
moving jet device 1 in an arrowed U direction during one
rotation) is represented by a symbol P.
[0020]
The ground G is cut by the cutting fluid jets Jl and J2
to form the cutting hole HC. As the ground
G is cut, a
solidification material (e.g. cement fluid) is delivered from
a discharge port (not shown) provided around a lower end portion
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of the jet device 1 via a solidification material flow passage
(not shown) in the jet device 1. Accordingly,
the
solidification material is mixed with an in-situ cut soil and
a cutting fluid (e.g. high-pressure water) and filled in the
cutting hole HC and then solidified to form an underground
consolidated body (not shown).
In Fig. 1, slime generated when cutting the ground, as
indicated by an arrowed direction AD, is discharged above the
ground via a gap S (a circular space) between the jet device
1 and an inner wall surface of the drilling hole HD.
[0021]
As described above, the nozzles N1, N2 are located at an
interval V in a vertical direction. The cutting
fluid jet J1
is Injected from the upward nozzle N1 in a downward skewed
direction, and the cutting fluid jet J2 is injected from the
downward nozzle N2 in an upward skewed direction. For this
purpose, when the jet device 11 is rotated on a cross section
(an optional identical cross section) a plurality of times and
pulled up, all flow lines of the cutting fluid jets J1, J2 are
shown in Fig. 2.
Specifically, according to the first embodiment, flow
lines of the cutting fluid jets Jl and J2 shown in Fig. 2 provide
a shape obtained when a plurality of straight lines by the
cutting fluid jet J1 (the same straight lines as the jet Jl)
parallel to each other extending from upper left to lower right
and a plurality of straight lines by the cutting fluid jet J2
(the same straight lines as the jet J2) parallel to each other
extending from lower left to upper right intersect on the right
side of the jet device 1 in Fig. 2 on a cross section (an optional
identical cross section).
Herein, the cross section (the optional identical cross
section) refers to a plane containing a central axis CL (Fig.
1) of the jet device 1 in Figs. land 2 and extending in a radial
direction and a vertical direction (upward and downward
directions in Fig. 2), which is found in the entire
circumference at 360 degrees with respect to the central axis
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CL of the jet device 1.
[0022]
The interval P (pitch) of a plurality of cutting fluid
jets Jl, Jl injected from upper left to lower right, or the
interval P (pitch) of a plurality of jets J2, J2 injected from
lower left to upper right on a plane on the right side of e.g.
the jet device 1 in Fig. 2 refers to the amount of upward moving
the jet device 1 during one rotation (the amount of pulling up
the same), e.g. 2.5cm in the embodiment shown in the drawings.
In Fig. 2, the interval in upward and downward directions
of the most downward flow line of the cutting fluid jet Jl and
the most downward flow line of the cutting fluid jet J2 is equal
to the distance V between the nozzles Ni and N2.
[0023]
In Fig. 2, an in-situ soil (ground, bedrock, rock, etc.)
found in flow lines of a plurality of the cutting fluid jets
J1, J2 extending parallel to each other at a predetermined
interval (pitch P) is cut by the cutting fluid jet.
An in-situ soil in a region not found on the flow lines
of the cutting fluid jets J1, J2 or in a region a surrounded
by the flow lines of the cutting fluid jets Jl, J2 is not cut
by the cutting fluid jets Jl, J2. In Fig. 2,
only one region
a surrounded by the flow lines of the cutting fluid jets J1,
J2 is shown by hatching.
[0024]
Since the in-situ soil found in the region a is not cut
by the cutting fluid jets J1, J2, the soil may remain in the
ground while a clod M found in the region a is not cut.
However, on a cross section (an optional identical cross
section) in Fig. 2, the largest clod which is not cut by the
flow lines of a plurality of the cutting fluid jets Jl, J2 on
the cross section to remain in the ground corresponds to a clod
M found in a rhombic region a in Fig. 2. The clod M found in
the region a in Fig. 2 has a smaller representative size than
those of clods shown in Figs. 10 and 11.
Since the clod M found in the region a in Fig. 2 has a
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smaller representative size, the clod M can readily pass a
circular space S (Fig. 1) between the jet device 1 and the inner
wall surface of the drilling hole HD together with slime. In
other words, a clod M found in the region a in Fig. 2 whose
representative size is small does not prevent the slime from
being discharged above the ground.
[0025]
Herein, main factors for determining a cutting diameter
D of the cutting hole HC include the injection pressure of the
cutting fluid jet J and the injection flow of the cutting fluid
jet J. The number of cutting and the rotational speed of the
jet device 1 also affect the cutting diameter D.
Inventors of the present invention found that a clay
ground has a cutting diameter D of 4m or more, and a sand ground
has a cutting diameter D of 5m or more.
In Fig. 1, the angle 0 in the nozzles N1, N2 (the inject
angle of jets J1, J2) is adjusted to adjust the injection
pressure of said cutting fluid jet J and to determine the cutting
diameter D.
[0026]
As another parameter in addition to the above described
parameters, the injection pressure of the cutting fluid jet J
is a uniaxial compressive strength of soil in the construction
ground G or more, for example, 300bar or more.
In addition, the injection flow Q of the cutting fluid
jet J is expressed by an equation Q:
Q=300 (liter/min.) x the number of nozzles.
In addition, the rotational speed of the jet device 1 is
5rpm, and the number of cutting is 1 to 2. Specifically,
each
time the jet device 1 is rotated half to one time, the jet device
1 is pulled up (or stepped-up).
[0027]
In the embodiment shown in the drawings, as described
above, the cutting diameter D can be determined by adjusting
the angle 0 in the nozzles N1, N2 (the inject angle of jets Jl,
J2).
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Consequently, in the embodiment shown in the drawings,
the angle 6 in the nozzles Ni, N2 (the inject angle of jets Jl,
J2) can preferably be adjusted.
Figs. 3 and 4 show a structure for adjusting the angle
e in nozzles Ni, N2 (the inject angle of jets Jl, J2) .
[0028]
First, the structure shown in Fig. 3 will be described.
Fig. 3 shows that a nozzle Ni is attached with respect
to a central axis CL of a jet device 1. The jet device
1 includes
a flow passage for a cutting fluid 1A, and a cutting fluid flows
through the flow passage for a cutting fluid 1A. The cutting
fluid is fed from a feed device above the ground (not shown) ,
pressurized by a pressure device (not shown) and fed in an
arrowed direction AB in Fig. 3 to be injected from the nozzle
Ni and a nozzle N2 in an arrowed direction AC.
In Fig. 3, a symbol 1B represents a notch for providing
a range of motion by adjusting the inject angle of the nozzle
Ni provided at the jet device 1.
[0029]
The structure for adjusting the inject angle shown in Fig.
3 is a structure for adjusting the inject angle of the nozzle
Ni, and includes a cover plate for adjusting a inject angle 2
and an insertion plate for adjusting a inject angle 3.
The cover plate for adjusting a inject angle 2 is a tabular
body extending in upward and downward directions placed
attached to the jet device 1 (only a casing of a pipe-shaped
jet device 1 is shown in Fig. 3) . An insertion portion 2A is
provided at the jet device 1 of the cover plate for adjusting
the inject angle 2 (on the left side of Fig. 3) , and the insertion
portion 2A is constructed so that the insertion plate for
adjusting a inject angle 3 can be inserted. The insertion
portion 2A forms an inner space of the cover plate for adjusting
a inject angle 2, and a bottom portion 2B of the insertion portion
2A is an outer surface (an outer wall surface) of the casing
of the jet device 1.
The size of the space formed by the insertion portion 2A
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in an elevational direction (a radial direction: right and left
directions in Fig. 4) gradually decreases from an inlet thereof
(a lower end portion of the cover plate for adjusting a inject
angle 2) in an upward direction in Fig. 4. The angle
(insertion
angle) formed by the bottom portion 2B of the insertion portion
2A (the outer surface of the casing of the jet device 1) and
an upper surface portion 2C of the insertion portion 2A is
represented by a symbol pl.
[0030]
The cover plate for adjusting a inject angle 2 is pivotably
supported with respect to a support shaft 2D of the jet device
1 around an upper end portion thereof, and is always energized
by an energizing device (e.g. a spring) (not shown) man arrowed
direction F or in a direction for pressing the cover plate for
adjusting a inject angle 2 on the jet device 1.
The nozzle N1 is fixed on said cover plate for adjusting
a inject angle 2 to be integrally pivoted with the cover plate
2. Thus, when the
cover plate for adjusting a inject angle
2 is pivoted from an initial position (when the cover plate for
adjusting a inject angle 2 is pressed on an outer wall surface
of the jet device 1: a position shown in Fig. 3) clockwise against
said energizing force F, the nozzle N1 is pivoted around the
support shaft 2D and pivoted in a direction for decreasing the
inject angle O.
[0031]
The insertion plate for adjusting a inject angle 3 is
overall a triangle pole body, comprising a bottom portion 3A
which contacts with the outer wall surface of the jet device
1 and an upper surface portion 3B which gradually increases the
thickness from an end portion toward a backward side ( from upper
to lower directions in Fig. 3). The angle of
the end portion
of the insertion plate for adjusting a inject angle 3 is
represented by a symbol p2. Herein, the relationship between
the insertion angle pl of the insertion portion 2A of the cover
plate for adjusting a inject angle 2 and the end portion angle
p2 of the insertion plate for adjusting a inject angle 3 is
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expressedby an equation: angle cp1 < angle cp2. Therefore,
when
the insertion plate for adjusting a inject angle 3 is inserted,
the cover plate for adjusting a inject angle 2 and the nozzle
N1 will be pivoted clockwise.
The insertion plate for adjusting a inject angle 3 can
be inserted into the insertion portion 2A of the cover plate
for adjusting a inject angle 2 (can be moved in an arrowed
direction AE). By adjusting
the amount of inserting the
insertion plate for adjusting a inject angle 3 into the
insertion portion 2A of the cover plate for adjusting a inject
angle 2, the inject angle 6 of the nozzle N1 can be adjusted
when the cover plate for adjusting the inject angle 2 and the
nozzle N1 are pivoted clockwise with respect to the support
shaft 2D against an energizing force F.
[0032]
Specifically, when the insertion plate for adjusting a
inject angle 3 is inserted in a direction for pressing the same
on the insertion portion 2A, the cover plate for adjusting a
inject angle 2 and the nozzle N1 are pivoted clockwise to
decrease the inject angle 9. Meanwhile, when the insertion
plate for adjusting the inject angle 3 is moved in a direction
so that it is removed from the insertion portion 2A, the cover
plate for adjusting a inject angle 2 and the nozzle N1 are pivoted
counterclockwise against the energizing force F to increase the
inject angle 6.
While the method for adjusting the inject angle e in the
nozzle Ni is described above, the inject angle e in the nozzle
N2 can be adjusted according to the same structure.
[0033]
Fig. 4 shows a structure for adjusting the inject angle
different from the one shown in Fig. 3.
In Fig. 4, the center of the nozzle N1 in a inject direction
is fixed on an output shaft 4A of a known stepping motor 4. The
output shaft 4A of the stepping motor 4 is attached to the jet
device (not shown). An arrowed
direction AC in Fig. 4
represents the inject direction of a cutting fluid jet Jl.
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In Fig. 4, by subjecting the stepping motor 4 to positive
rotation or negative rotation by a proper angle, the nozzle Ni
is pivoted by an optional central angle to adjust the inject
angle 0 of the nozzle Ni.
The structure for adjusting the inject angle e in Fig.
4 can be applied to the nozzle N2.
[0034]
In the embodiment shown in the drawings, the largest
representative size of the clod M.which is not cut by a cutting
fluid jet J and instead is peeled off from a construction ground
G is affected by the size of a pitch (a pitch for stepping up
the jet device) represented by a symbol P in Fig. 2.
The pitch P is a parameter which varies according to the
interval V in a vertical direction between the nozzles Ni, N2.
In other words, when the interval V in a vertical direction
between the nozzles Ni, N2 is adjusted, the pitch P can be
adjusted.
Figs. 5 and 6 illustrate a structure for adjusting the
interval V in a vertical direction between the nozzles Ni, N2.
[0035]
First, the structure in Fig. 5 will be described.
Fig. 5 is a schematic view showing an attaching portion
of nozzles Ni and N2 of a jet device 1 viewed from a side face.
The jet device 1 is divided into halves at a predetermined
position (at a predetermined position in a vertical direction)
between the nozzles Ni, N2, and a spacer 5 of a thickness T is
placed between the jet devices 101, 102 divided into halves.
Herein, an internal structure of the spacer 5 is the same
as the jet devices 101 and 102, and fluid passages in the jet
devices 101, 102 are connected by a fluid passage in the spacer
and connecting means (e.g. a swivel joint) (not shown). Thus,
the jet devices 101, 102 and the spacer 5 serve as a jet device
to inject or deliver a cutting fluid (and a solidification
material).
The jet devices 101, 102 and the spacer 5 are connected
by a known technology (e.g. bonding, fastening means, etc.).
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[0036]
The interval V in a vertical direction between the nozzles
Ni, N2 can be adjusted by placing the spacer 5 between the jet
devices 101 and 102.
If the interval V in a vertical direction between the
nozzles Ni, N2 is set at the minimum interval between the nozzles
Ni, N2 (the interval in a vertical direction) when the spacer
is not placed between the jet devices 101, 102, for example,
the interval in a vertical direction between the nozzles Ni,
N2, is "V+T" when the spacer 5 is placed between the jet devices
101, 102.
Further, a plurality of spacers 5 having a different
thickness T are prepared, and the range of the interval in a
vertical direction between the nozzles Ni, N2 can be adjusted
accordingly.
[0037]
Fig. 6 shows a structure for adjusting the interval V in
a vertical direction different from the one in Fig. 5. In Fig.
6, the interval V in a vertical direction is adjusted by using
a known rack and a pinion gear structure.
In Fig. 6, a rotating shaft 7A of a pinion gear 7 is
attached to a jet device (not shown) to mesh with a rack 6. The
rack 6 is fixed to the nozzle Ni to extend parallel to a central
axis of the jet device 1 (Fig. 1). By subjecting
the pinion
gear 7 to positive rotation or negative rotation to move the
rack 6 upward and downward, the nozzle Ni will move upward and
downward. Accordingly, the interval in a vertical direction
between the nozzles Ni, N2 can be adjusted.
[0038]
In Fig. 6, an arrowed direction AC represents a direction
of a cutting fluid jet Jl.
In addition, in Fig. 6 in which only the nozzle Ni is
constructed to move upward and downward, only the nozzle N2 can
be fixed to a rack 6 to move upward and downward. Further,
when the nozzles Ni, N2 are fixed to another rack, respectively,
and the pinion gear 7 is rotated, the nozzles Ni, N2 will move
17
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in a direction opposite to upward and downward directions to
adjust the interval V in a vertical direction between the
nozzles Ni, N2.
[0039]
According to the first embodiment shown in the drawings,
the nozzles Ni, N2 of the jet device 1 are located at an interval
in a vertical direction, the cutting fluid jet J1 is injected
from the upward nozzle Ni in a downward skewed direction, and
the cutting fluid jet J2 is injected from the downward nozzle
N2 in an upward skewed direction. Accordingly, if flow lines
of the cutting fluid jets Jl and J2 are in a region on the right_
side of the jet device 1 in Fig. 2 on an optional position plane,
they provide a plurality of straight lines parallel to each
other extending from upper left to lower right and a plurality
of straight lines parallel to each other extending from lower
left to upper right.
Thus, as shown in Fig. 10, a region which is not cut by
a cutting fluid jet never extends parallel to flow lines of the
cutting fluid jet, and flow lines of another cutting fluid jet
assuredly intersects the region which is not cut thereby.
[0040]
Specifically, even if a region which is not cut by a
cutting fluid jet is found instantaneously, the region will
thereafter be cut by intersecting any of the cutting fluid jets
Jl, J2. Accordingly, a larger representative size of a region
which is not cut by the cutting fluid jet is prevented.
Consequently, according to the first embodiment shown in
the drawings, the largest clod M which is not cut by the cutting
fluid jet to remain in the ground has a smaller representative
size than the large clods MI shown in Figs. 10 and 11, and readily
passes a circular space (Figs. 1 and 11) between the jet device
1 and an inner wall surface of a drilling hole HD. As a result,
discharge of slime above the ground is not prevented.
[0041]
In the embodiment shown in the drawings, since the angle
6 in the nozzles Ni, N2 (the inject angle of the cutting fluid
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jets Jl, J2) can be adjusted, the cutting diameter D can
efficiently be adjusted according to the type of soil in a
construction ground G.
Additionally, in the embodiment shown in the drawings,
since the interval V in a vertical direction between the nozzles
Ni, N2 can be adjusted, the pitch P of jet flow lines shown in
Fig. 2 can be adjusted. Therefore,
according to the condition
of a construction site, the largest representative size of the
clod M which is not cut by a jet to remain in the ground can
be adjusted.
[0042]
Next, a second embodiment of the present invention will
be described with reference to Fig. 7.
In Fig. 7, jets Si, J2 are injected from an upward nozzle
Ni of a jet device 10. As described in the first embodiment
shown in Figs. 1 to 6, the jet Si is injected from the nozzle
Ni in a downward skewed direction relative to a horizontal
direction, and the jet J2 is injected from the nozzle N2 in an
upward skewed direction relative to the horizontal direction.
Although Fig. 7 does not clearly show, as for the jets
Si, J2, a radial direction inward (central) portion of a cross
section thereof is a jet flow of a partition forming material,
and its circumference is surrounded by a jet flow of a
high-pressure air. However, even
if the high-pressure air is
not ejected, the second embodiment can be implemented.
For example, the partition forming material is a solution
containing 5% by weight of a thickener (e.g. guar gum as a natural
water-soluble polymer material) and 5% by weight of sodium
silicate (water glass). The partition
forming material is
injected to the soil to be mixed with an in-situ soil to form
a separation layer LD.
[0043]
Meanwhile, jets J3, J4 injected from downward nozzles N3,
N4 are jet flows of a solidification material.
By injecting the jets J3, J4, a solidification material
is mixed with a mixture of the partition forming material and
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the cut in-situ soil.
In order to inject the solidification material by
injecting the jets J3, J4 from the jet device 10 which is pulled
up by rotating the same, even if the in-situ soil is e.g. a clay,
a mixture of the in-situ soil (clay) and the partition forming
material are favorably mixed with the solidification material.
Herein, a mixture of the in-situ soil (clay) and the
partition forming material passes a circular space S between
the jet device 10 and an inner wall surface of a drilling hole
HD as shown in an arrowed direction AD as slime to be discharged
above the ground. Nevertheless,
since the mixture of the
in-situ soil (clay) and the partition forming material contains
no solidification material, it is not necessary for the mixture
to be treated as an industrial waste, thereby no deterioration
of working conditions.
[0044]
As shown in Fig. 7, by cutting a ground G by injecting
the partition forming material by injecting the jets Jl, J2,
a separation layer LD is formed in an upward region of a space
IJ cut by the jets J1, J2 (a space filled with the in-situ soil
and the partition forming material). The separation
layer LD
serves as a divider so that the solidification material injected
from the nozzles N3, N4 does not flow into a circular space S
between the jet device 10 and the inner wall surface of the
drilling hole HD.
By injecting a solidification material in a downward
region of the space IJ cut by the jets Jl, J2 by injecting the
jets J3, J4, a layer LC of a rich-mixed solidification material
(having a low W/C, the ratio of water to a solidification
material) is formed in a downward region of the space IJ.
[0045]
Herein, the downward jets J3, J4 collide with a cut wall
W (an inner wall surface of a diameter-expanded cutting hole
cut by the jets J1, J2). Then, if they
are rolled up as shown
in an arrowed direction AN, a solidification material might be
mixed with the separation layer LD (comprising a mixture of the
CA 02963217 2017-03-30
partition forming material and the cut soil). When the
solidification material is mixed with the separation layer LD,
the solidification material might be discharged above the
ground as slime.
In order to prevent from the solidification material from
being discharged above the ground, it is necessary for the
downward jets J3, J4 to roll down downward as shown in an arrowed
direction AG when they collide with the cut wall W. Thus, as
shown in Fig. 7, the downward jets J3, J4 face downward by an
angle with respect to a horizontal direction HO.
Inventors of the present invention experimentally found
that when the injection pressure of the downward jets J3, J4
is 100bar, said inclined angle (3 is preferably 15 , and when
the injection pressure of the jets J3, J4 is 200bar, the inclined
angle [3 is preferably 30 . Also, mixture
of a solidification
material with a separation layer LD was prevented.
[0046]
According to the second embodiment in Fig. 7, as the jet
device 10 is pulled up, the size of the layer LC of the
solidification material in a vertical direction becomes larger
(thicker), and the separation layer LD (the layer of the
partition forming material) always moves in an upward direction
of the layer LC of the solidification material.
To provide a separation layer LD composed of a partition
forming material, a mixture of the partition forming material
and soil is discharged above the ground as slime (a mixture of
the partition forming material and the cut soil). But, a
rich-mixed solidification material in the layer LC of the
solidification material is hardly discharged above the ground.
Since the solidification material is not discharged above the
ground, waste of the solidification material is reduced, and
the amount of slime to be treated as an industrial waste in a
dedicated plant is reduced.
In addition, the solidification material is injected by
the jets J3, J4 from the downward nozzles N3, N4 of the jet device
10, and the jet device 10 is pulled up by rotating the same.
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Consequently, even if the viscosity of an in-situ soil (e.g.
clay) is high, a mixture of the in-situ soil (clay) and the
partition forming material is favorably mixed with the
solidification material.
[0047]
Other constructions and effects of the second embodiment
shown in Fig. 7 are the same as the constructions and effects
of the first embodiment shown in Figs. 1 to 6.
[0048]
It should be note that the explanations relating to the
embodiments shown in the drawings are merely examples and that
the technical scope covered by the present invention is not
restricted by such the explanations of the embodiments shown
in the drawings. The embodiments composed of substantially
the same technical concept as disclosed in the claims of the
present invention and expressing a similar effect are included
in the technical scope of the present invention.
In the embodiment shown in the drawings, for example, two
nozzles are provided, but if nozzles are symmetrically disposed
about a point with respect to a central axis CL of a jet device,
3 or more nozzles can be provided.
In addition, in the embodiment shown in the drawings, a
solidification material is delivered from a discharge port
provided in a downward direction of the jet device and delivered
to a mixture of a cut in-situ soil and a cut fluid. However,
like a cutting fluid jet J or together therewith, the
solidification material may be injected in an outward radial
direction.
EXPLANATION OF LETTERS OR NUMERALS
[0049]
1, 10, 11.. .Jet device
HC...Cutting hole
HD...Drilling hole
IJ...Cut space
J, J1, J2.. .Cutting fluid jet
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LC.. Layer of solidification material
LD...Layer of partition forming material (separation layer)
N, Ni, N2, N3, N4...Nozzle (inject nozzle)
S.. .Circular space
W...Cut wall (inner wall surface of cutting hole)
23
