WO2016051858A1

WO2016051858A1 - Ground improving method

Info

Publication number: WO2016051858A1
Application number: PCT/JP2015/065176
Authority: WO
Inventors: Ataru HANEDA (羽田中)
Original assignee: 有限会社大翔化学研究所; ソニックファウンデーションピーティーイーエルティーディー
Priority date: 2014-10-03
Filing date: 2015-05-27
Publication date: 2016-04-07
Also published as: CA2963217A1; AU2015326129B2; JP2016075040A; CA2963217C; EP3202982A4; EP3202982A1; AU2015326129A1; SG11201702724XA; US20180112368A1; EP3202982B1

Abstract

The purpose of the present invention is to provide a ground improving method that can prevent soil clumps with large representative dimensions from remaining. To this end, in the ground improving method of the present invention, injecting apparatuses (1, 10) inject cutting fluid (e.g., high-pressure water or high-pressure air, sometimes including a solidification material) to perform cutting, supply the solidification material, and mix and stir the cut ground (G), fluid, and solidification material to produce an underground consolidated body. The injecting apparatuses (1, 10) include a plurality of nozzles (N1, N2) positioned in the vertical direction with spaces therebetween. When injecting the cutting fluid, the injecting apparatuses inject the cutting fluid obliquely downward (J1) from an upper nozzle (N1), and inject the cutting fluid obliquely upward (J2) from a lower nozzle (N2).

Description

Ground improvement method

The present invention cuts a ground fluid to be improved by injecting a cutting fluid, supplies a solidified material, mixes and stirs the ground, the fluid and the solidified material, and forms an underground consolidated body. This is related to the ground improvement method.

An example of the conventional technique (for example, refer patent document 1) of the ground improvement construction method which concerns is demonstrated with reference to FIG.
In FIG. 8, a rod-shaped injection device 11 is inserted into a borehole HD drilled in the ground G to be improved. In order to inject the jet (J: cutting fluid jet) of cutting fluid (for example, high-pressure water) into underground G, injection device 11 is provided with injection nozzle N which injects cutting fluid jet J on the side. . A plurality of injection nozzles N are provided at positions symmetrical with respect to the central axis CL of the injection device 11 (for example, two in FIG. 8), and the vertical positions of the plurality of injection nozzles N (FIG. 8). The position in the vertical direction in FIG. 11 is the same.
Although not shown, the ejection device 11 has a cutting fluid channel (cutting fluid pipe: not shown) provided therein, and the cutting fluid is ejected from a supply device (not shown) provided on the ground. Is supplied to the internal cutting fluid flow path, and becomes a cutting fluid jet J from the injection nozzle N and is jetted radially outward (in the horizontal direction).

In FIG. 8, the ejection device 11 is gradually pulled up to the ground side (upward in FIG. 8) while ejecting the cutting fluid jet J into the ground, for example, rotating in the arrow R direction. As a result, the ground G is cut by the cutting fluid jet J, and the expanded cutting hole HC having the inner wall surface W is formed while the in-situ soil and the cutting fluid are mixed.
At the same time, the solidifying material (for example, cement) is discharged from a discharge port (not shown) provided in the vicinity of the lower end portion of the injection device 11 through the solidification material flow path (not shown) in the injection device 11. By discharging into the expanded hole HC, the ground solid body (not shown) is formed by mixing with the cut in-situ soil. Here, as with the cutting fluid jet J, or together with the cutting fluid jet J, there is a case where the solidified material is jetted radially outward.
When the ground G is cut by the cutting fluid jet J, slime that is a mixture of the cut in-situ soil and the cutting fluid is generated. As shown by an arrow AD, this slime is discharged to the ground through a gap S (annular space) between the injection device 11 and the inner wall surface of the boring hole HD.

In FIG. 9, in the ground G cut by the cutting fluid jet J, all streamlines of the cutting fluid jet J when the injection device 11 is rotated a plurality of times and pulled up in the same cross section are represented. As shown in FIG. 9, all streamlines of the cutting fluid jet J extend in parallel with a predetermined interval P / 2 (P is a pulling amount that is pulled up while the injection device 11 makes one revolution: pitch). It is expressed as a plurality of existing straight lines L. In FIG. 9, since the cutting fluid jet J is ejected from the two nozzles N, the interval between the streamlines of the cutting fluid jet J is ½ of the pitch P.
In FIG. 9, the in-situ soil (ground, rock, rock, etc.) existing in a plurality of cutting fluid jets J extending in parallel with a predetermined interval (1/2 of the pitch P) is the jet J The in-situ soil cut by is mixed with the cutting fluid and discharged as a slime to the ground side.

However, since the jet J is not injected into the region between the plurality of cutting fluid jets J (region of the interval P / 2), the region between the plurality of jets J jetted in parallel is shown in FIG. In the same manner, there is a possibility that the soil block M having a large representative dimension (the largest dimension among the longitudinal dimension, the lateral dimension, and the height dimension) remains without being cut.
When the large soil mass M remains without being cut, as shown in FIG. 11, the large soil mass M becomes a gap S (annular space) between the inner wall surface of the boring hole HD and the injection device 11. It is difficult to pass through, and the gap S (annular space) is blocked, and the slime is prevented from being discharged to the ground side.
Therefore, in the ground improvement method described above, there is a demand for a technique for preventing the clot M having a large representative size from remaining without being cut. However, such a technique (a technique for preventing the clot M having a large representative size from remaining without being cut) has not been proposed yet.

JP-A-7-76821

The present invention has been proposed in view of the above-described problems of the prior art, and an object of the present invention is to provide a ground improvement method capable of preventing a lump having a large representative dimension from remaining.

In the ground improvement method of the present invention, cutting fluid (for example, high-pressure water or high-pressure air: including the case of injecting solidified material) is injected from the injection device (1, 10) to perform cutting, and the solidified material is supplied. In the ground improvement method for mixing the ground (G) that has been cut, the fluid, and the solidifying material, stirring, and creating a ground solid body,
A plurality of nozzles (N1, N2) are positioned in the injection device (1, 10) at intervals in the vertical direction, and when the cutting fluid is injected, cutting is performed obliquely downward from the upper nozzle (N1). The cutting fluid is jetted (cutting fluid jet J1), and the cutting fluid is jetted obliquely upward from the lower nozzle (N2) (cutting fluid jet J2).

In this invention, it is preferable to have the process of adjusting the angle ((theta): jet angle of jet J1, J2) of a nozzle (N1, N2).
Moreover, in this invention, it is preferable to have the process of adjusting the vertical space | interval V between nozzles (N1, N2).

Further, in the present invention, the partition forming material is jetted as a cutting fluid from above the jetting device (10) (jets J1, J2), and the solidified material is jetted from below the jetting device (10) (jets J3, J4). Is preferred.

According to the present invention having the above-described configuration, the plurality of nozzles (N1, N2) are positioned at intervals in the vertical direction, and the cutting fluid is ejected obliquely downward from the upper nozzle (N1) ( By jetting the cutting fluid obliquely upward from the lower nozzle (N2) (jet J1), the plane at any position (see FIGS. 2 and 9: includes the central axis CL of the injection device 1). Of the cutting fluid (jet J1, jet J2) ejected in a certain time in a plane extending in the radial direction and the vertical direction (existing in all directions of 360 ° with respect to the central axis CL of the injection device 1) The streamline has a shape in which a plurality of parallel straight lines (J1, J2) extending in an oblique direction intersect.
Therefore, even if there is a region (clot G) that is not cut by the cutting fluid jet (J) at a certain moment, the clot (G) is then cut by any of the cutting fluid jets (jet J1, jet J2). Is done. In other words, even if a large clot (G) remains without being cut by the cutting fluid jet (jet J1, jet J2) at a certain moment, the clot (G) is subsequently cut by the cutting fluid jet (jet J1, jet J2). ) Is always cut by one of the streamlines.

Therefore, according to the present invention, it is possible to prevent a region (clot G) that is not cut by a jet of cutting fluid (jet J) from existing over a long distance, and a clot (G) having a large representative dimension is cut. It is prevented from extending and remaining parallel to the streamline of the working fluid jet (jet J), and the region not cut by the cutting fluid jet (J) (clump M) becomes too large (representative). (The dimension becomes too large).
And the size of the largest earth block (M) which can remain | survive without cutting becomes small, and passes easily the clearance gap S (annular space) between an injection apparatus (1) and the inner wall face of a boring hole (HD). Therefore, the maximum size of the mass (M) that can remain does not prevent the slime from being discharged to the ground side.

In the present invention, if the configuration is such that the angle of the nozzles (N1, N2) (θ: jet angle of the jets J1, J2) is adjusted, it is efficient in accordance with the type of soil of the construction ground (G). It is possible to cut with a cutting diameter (D).
Further, in the present invention, if the vertical interval (V) between the nozzles (N1, N2) is adjustable, the pitch (P) between the streamlines of the jet (J) of the cutting fluid can be adjusted. Accordingly, it is possible to adjust the size of the maximum mass (M) that can remain without being cut by the cutting fluid jet (J) in accordance with the situation of the construction site.

In the present invention, a partition forming material is jetted as a cutting fluid (jet J1, J2) from above (nozzle) of the jetting device (10), and a solidified material is jetted from below (nozzle) of the jetting device (10) ( If the jets J3 and J4), the partition forming material layer (separation layer LD) in which the partition forming material and the cut in-situ soil are mixed is formed above, and the partition forming material, the cut in-situ soil and the solidified material are formed. A layer (LC) of the solidified material mixed with is formed below.
Therefore, only the mixture of the partition forming material and the soil in the separation layer (LD) composed of the partition forming material is discharged to the ground side as a slime (mixture of the partition forming material and the cut soil), and the solidified material layer The rich blended material in (LC) is hardly discharged to the ground side. And since a solidification material is not discharged | emitted on the ground side, waste of a solidification material is suppressed and the generation amount of the slime which should be processed in a special treatment facility as industrial waste decreases.
Further, since the solidification material is jetted from (below the nozzle) of the jetting device (10) (jets J3, J4), even if the in-situ soil has a high viscosity (for example, clay), it is separated from the in-situ soil (clay). The mixture of forming materials is well mixed with the solidifying material.

It is explanatory drawing which shows 1st Embodiment of this invention. It is explanatory drawing which shows the state by which the ground is cut by 1st Embodiment. It is explanatory drawing which shows an example of the mechanism which adjusts the injection angle of a nozzle in 1st Embodiment. It is explanatory drawing which shows the example different from FIG. 3 of the mechanism which adjusts the injection angle of a nozzle in 1st Embodiment. It is explanatory drawing which shows an example of the mechanism which adjusts the space | interval of a nozzle in 1st Embodiment. It is explanatory drawing which shows the example different from FIG. 5 of the mechanism which adjusts the space | interval of a nozzle in 1st Embodiment. It is explanatory drawing which shows 2nd Embodiment of this invention. It is explanatory drawing which shows the conventional ground improvement construction method. It is explanatory drawing which shows the state by which the ground is cut by the conventional ground improvement construction method. It is explanatory drawing which shows an example of the cutting soil block by the conventional ground improvement construction method. It is explanatory drawing which shows the problem in the conventional ground improvement construction method.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
First, a first embodiment of the present invention will be described with reference to FIGS.
In the prior art shown in FIGS. 8 and 11, the vertical positions of the pair of nozzles N (the vertical positions in FIGS. 8 and 11) are the same, and also include a cutting fluid (for example, high-pressure water: solidified material). In some cases, the jet (cutting fluid jet J) is ejected in the horizontal direction.
On the other hand, in the embodiment shown in FIGS. 1 to 6, the vertical positions (the vertical positions in FIG. 1) of the nozzles N1 and N2 are different, and the cutting fluid is inclined in the horizontal direction. Jet J is being jetted.

In FIG. 1, a rod-like injection device 1 for injecting a jet J (cutting fluid jet) of a cutting fluid (for example, high-pressure water) is inserted into a borehole HD drilled in the ground G to be improved. Yes.
Nozzles N1 and N2 are provided on the side surface of the ejection device 1, and cutting fluid jets J1 and J2 are ejected from the nozzles N1 and N2. In this specification, the jets J1 and J2 may be collectively referred to as a jet J.
The nozzles N1 and N2 are arranged at an interval V in the vertical direction (up and down direction in FIG. 1). In FIG. 1, symbol CL indicates the central axis of the injection device 1.

The cutting fluid jet J1 is ejected from the upper nozzle N1 obliquely downward in the horizontal direction, and the ejection direction of the cutting fluid jet J1 is inclined downward by an angle θ with respect to the horizontal direction HO. Yes. The horizontal direction HO is a direction extending perpendicular to the central axis CL of the injection device 1.
On the other hand, the cutting fluid jet J2 is jetted from the lower nozzle N2 toward the upper side in the horizontal direction, and the jetting direction of the cutting fluid jet J2 is inclined upward by an angle θ with respect to the horizontal direction HO. ing.
In FIG. 1, symbol D denotes a cutting diameter of a region (cutting hole HC) cut by the jets J 1 and J 2, and a cutting radius of the cutting hole HC (a distance from the central axis CL of the injection device 1 to the inner wall of the cutting hole HC). Is D / 2.

A well-known device can be applied to the injection device 1, and a cutting fluid is introduced into the injection device 1 from a supply device (not shown) provided on the ground, and a cutting fluid channel (not shown) in the injection device 1 is shown. The cutting fluid jets J1 and J2 are ejected radially outward (under the ground) from the nozzles N1 and N2.
The ejection device 1 rotates as indicated by an arrow R while ejecting cutting fluid jets J1 and J2 to cut the ground G, and is pulled up toward the ground surface (upward: see arrow U in FIG. 1). .
The pull-up amount of the injection device 1 (the amount of movement that moves in the direction of the arrow U while the injection device 1 makes one revolution) is represented by the symbol P.

The ground G is cut by the cutting fluid jets J1 and J2, and the cutting hole HC is formed. Simultaneously with the cutting of the ground G, the solidified material (for example, cement milk) is discharged from a discharge port (not shown) provided in the vicinity of the lower end portion of the injection device 1 through the solidification material flow path (not shown) in the injection device 1. As a result, the solidified material is mixed with the in-situ soil from which the solidified material has been cut and a cutting fluid (for example, high-pressure water), filled into the cutting hole HC, and then solidified by solidifying (not shown). Is created.
In FIG. 1, the slime generated during ground cutting is discharged to the ground through a gap S (annular space) between the injection device 1 and the inner wall surface of the boring hole HD as indicated by an arrow AD.

As described above, the nozzles N1 and N2 are positioned at an interval V in the vertical direction, the cutting fluid jet J1 is ejected obliquely downward from the upper nozzle N1, and the cutting is performed obliquely upward from the lower nozzle N2. In order to inject the fluid jet J2, all streamlines of the cutting fluid jets J1 and J2 when the injection device 11 is rotated a plurality of times and pulled up in a certain cross section (arbitrary identical cross section) are expressed in FIG. As shown.
That is, according to the first embodiment, in FIG. 2, the flow lines of the cutting fluid jet J1 and the cutting fluid jet J2 are on the right side of the injection device 1 in FIG. In the plane, a plurality of parallel straight lines extending from the upper left to the lower right by the cutting fluid jet J1 (the same straight line as the jet J1) and a plurality of parallel straight lines extending from the lower left to the upper right by the cutting fluid jet J2. (The same straight line as the jet J2) intersects.
Here, a certain cross section (arbitrary identical cross section) means, for example, in FIG. 1 and FIG. 2, including the central axis CL (see FIG. 1) of the injection device 1 in the radial direction and the vertical direction (vertical direction in FIG. ) Extending over 360 ° with respect to the central axis CL of the injection device 1.

In FIG. 2, for example, a plurality of cutting fluid jets J 1 and J 1 that are ejected from the upper left to the lower right in the plane on the right side of the ejection device 1, or a plurality of jets ejected from the lower left to the upper right. The interval P (pitch) between J2 and J2 is the amount of movement (pull-up amount) that moves upward while the injection device 1 makes one revolution, and is, for example, 2.5 cm in the illustrated embodiment.
In FIG. 2, the vertical interval between the streamline of the lowermost cutting fluid jet J1 and the streamline of the cutting fluid jet J2 is equal to the distance V between the nozzles N1 and N2.

In FIG. 2, in-situ soil (ground, rock, rock, etc.) existing in the streamlines of a plurality of cutting fluid jets J1, J2 extending in parallel at a predetermined interval (pitch P) is the cutting fluid. It is cut by a jet.
The in-situ soil existing in the region that does not exist on the streamlines of the cutting fluid jets J1 and J2, that is, the region α between the streamlines of the cutting fluid jets J1 and J2, is not cut by the cutting fluid jets J1 and J2. In FIG. 2, the region α between the streamlines of the cutting fluid jets J1 and J2 is illustrated with only one hatching.

Since the in-situ soil existing in the region α is not cut by the cutting fluid jets J1 and J2, there is a possibility that the soil mass M existing in the region α may remain uncut.
However, in the cross section in FIG. 2 (arbitrary identical cross section), if the flow lines of the plurality of cutting fluid jets J1 and J2 in the cross section are, the maximum mass remaining without being cut by the cutting fluid jets J1 and J2 is 2 is a block M present in the diamond-shaped region α in FIG. 2 has a smaller representative dimension than that of the large chunk of representative dimensions shown in FIGS. 10 and 11.
2 has a small representative size, it can easily pass through the annular space S (see FIG. 1) between the injection device 1 and the inner wall surface of the boring hole HD together with the slime. it can. In other words, the clot M having a small representative size in the region α in FIG. 2 does not hinder the discharge of the slime to the ground side.

Here, the main factors that determine the cutting diameter D of the cutting hole HC are the injection pressure of the cutting fluid jet J and the injection flow rate of the cutting fluid jet J. The number of cuttings and the rotational speed of the injection device 1 are also determined by the cutting diameter D. Affects.
According to the inventor's research, the cutting diameter D is 4 m or more in clay ground, and 5 m or more in sand ground.
In FIG. 1, adjusting the angle θ (injection angle of the jets J1 and J2) at the nozzles N1 and N2 adjusts the injection pressure of the cutting fluid jet J, so that the cutting diameter D can be determined.

To further illustrate the above-described parameters, the injection pressure of the cutting fluid jet J is equal to or higher than the uniaxial compressive strength of the soil in the construction ground G, for example, 300 bar or higher.
Further, the injection flow rate Q of the cutting fluid jet J is expressed by the following equation: Q = 300 (liter / min.) × number of nozzles.
In addition to this, the rotation speed of the injection device 1 is 5 rpm, and the number of times of cutting is 1 to 2 times. That is, the injection device 1 is raised (steps up) every time the injection device 1 makes half to one rotation.

In the illustrated embodiment, as described above, the cutting diameter D can be determined by adjusting the angle θ (the jet angle of the jets J1 and J2) at the nozzles N1 and N2.
Therefore, in the illustrated embodiment, it is preferable that the angle θ (the jet angle of the jets J1 and J2) at the nozzles N1 and N2 can be adjusted.
3 and 4 show a mechanism for adjusting the angle θ (the jet angle of the jets J1 and J2) at the nozzles N1 and N2.

First, the mechanism of FIG. 3 will be described.
FIG. 3 shows a state in which the nozzle N1 is attached to the central axis CL of the injection device 1, and the injection device 1 includes a cutting fluid channel 1A, and the cutting fluid channel 1A contains a cutting fluid. Shed. The cutting fluid is supplied from a supply device (not shown) on the ground, is pressurized by a pressurization device (not shown), flows in the direction of arrow AB in FIG. 3, and is ejected from nozzles N1 and N2 in the direction of arrow AC. .
In FIG. 3, reference numeral 1 B is a notch for securing a movable range by adjusting the injection angle of the nozzle N 1 provided in the injection device 1.

The injection angle adjustment mechanism shown in FIG. 3 is a mechanism for adjusting the injection angle of the nozzle N1, and is provided with an injection angle adjustment address plate 2 and an adjustment insertion plate 3.
The injection angle adjusting plate 2 is a plate-like body extending in the vertical direction, and is attached to the injection device 1 (only the casing of the tubular injection device 1 is shown in FIG. 3). An insertion portion 2A is provided on the injection device 1 side (left side in FIG. 3) of the injection angle adjusting plate 2, and the insertion portion 2A is configured such that the adjustment insertion plate 3 can be inserted. . The insertion portion 2A forms an inner space of the injection angle adjusting cover plate 2, and the bottom surface portion 2B of the insertion portion 2A is the outer surface (outer wall surface) of the casing of the injection device 1.
The height direction (radial direction: left and right direction in FIG. 4) dimension of the space formed by the insertion portion 2A gradually decreases from the entrance (the lower end portion of the injection angle adjusting plate 2) toward the upper side in FIG. . An angle (insertion angle) formed by the bottom surface portion 2B of the insertion portion 2A (the outer surface of the casing of the injection device 1) and the upper surface portion 2C of the insertion portion 2A is indicated by reference numeral φ1.

The injection angle adjusting support plate 2 is pivotally supported near the upper end of the injection angle adjusting plate 2D with respect to the support shaft 2D on the injection device 1 side, and is always indicated by an arrow F by a biasing device (spring or the like) not shown. It is biased in the direction, that is, the direction in which the injection angle adjusting plate 2 is pressed against the injection device 1.
The nozzle N 1 is fixed to the injection angle adjusting coating plate 2 and rotates integrally with the coating plate 2. Therefore, the injection angle adjusting plate 2 is rotated clockwise from the initial position (the state in which the injection angle adjusting plate 2 is pressed against the outer wall surface of the injection device 1: the position shown in FIG. 3) against the urging force F. When the nozzle N1 rotates, the nozzle N1 rotates around the support shaft 2D and rotates in the direction in which the injection angle θ decreases.

The adjustment insertion plate 3 is a triangular prism as a whole, and includes a bottom surface portion 3A that comes into contact with the outer wall surface of the injection device 1, and an upper surface portion 3B that gradually increases in thickness from the tip portion toward the rear (from the top to the bottom in FIG. And have. The angle of the distal end portion of the adjustment insertion plate 3 is indicated by the symbol φ2. Here, the insertion angle φ1 of the insertion portion 2A of the injection angle adjusting plate 2 and the tip end angle φ2 of the adjustment insertion plate 3 satisfy an angle φ1 <angle φ2. Therefore, when the leveling insertion plate 3 is inserted, the injection angle adjusting plate 2 and the nozzle N1 are rotated clockwise.
The adjustment insertion plate 3 is freely insertable (movable in the direction of the arrow AE) into the insertion portion 2A of the injection angle adjustment target plate 2, and the adjustment insertion plate 3 is inserted into the insertion portion 2A of the injection angle adjustment target plate 2. By adjusting the insertion amount to be inserted into the nozzle N1, the injection angle θ of the nozzle N1 when the injection angle adjusting plate 2 and the nozzle N1 are rotated clockwise with respect to the support shaft 2D against the urging force F is set. Can be adjusted.

That is, if the adjustment insertion plate 3 is inserted in the direction to be pushed into the insertion portion 2A, the injection angle adjustment target plate 2 and the nozzle N1 rotate clockwise, and the injection angle θ decreases. On the other hand, if the adjustment insertion plate 3 is moved in a direction to remove it from the insertion portion 2A, the urging force F causes the injection angle adjustment target plate 2 and the nozzle N1 to rotate counterclockwise, increasing the injection angle θ. .
In the above description, the adjustment of the injection angle θ in the nozzle N1 has been described, but the injection angle θ can be adjusted for the nozzle N2 by the same mechanism.

FIG. 4 shows an injection angle adjusting mechanism different from FIG.
In FIG. 4, the vicinity of the center in the injection direction of the nozzle N 1 is fixed to the output shaft 4 A of the known stepping motor 4. The output shaft 4A of the stepping motor 4 is attached to an injection device (not shown). In addition, arrow AC in FIG. 4 has shown the injection direction of the fluid jet J1 for cutting.
In FIG. 4, by rotating the stepping motor 4 forward or backward by an appropriate angle, the nozzle N1 can be rotated by an arbitrary center angle, so that the injection angle θ of the nozzle N1 can be adjusted.
The mechanism for adjusting the injection angle θ according to FIG. 4 can also be applied to the nozzle N2.

In the illustrated embodiment, the maximum size of the mass M that can be peeled off from the construction ground G without being cut by the cutting fluid jet J is a dimension of a pitch (pitch for stepping up the injection device) indicated by a symbol P in FIG. Affected by.
The pitch P is a different parameter if the vertical interval V between the nozzles N1 and N2 varies. In other words, the pitch P can be adjusted by adjusting the vertical interval V between the nozzles N1 and N2.
5 and 6 illustrate a mechanism for adjusting the vertical distance V between the nozzles N1 and N2.

First, the mechanism of FIG. 5 will be described.
FIG. 5 is an explanatory view of the vicinity of the attachment portion of the nozzles N1 and N2 of the injection device 1 as viewed from the side. The injection device 1 is divided into two at a predetermined position (vertical direction predetermined position) between the nozzles N1 and N2. A spacer 5 having a thickness dimension T is interposed between the divided injection devices 101 and 102.
Here, the internal structure of the spacer 5 is the same as that of the ejection devices 101 and 102, and the fluid path in the ejection devices 101 and 102 is connected to the fluid path in the spacer 5 and connection means (not shown) such as a swivel joint. ). Therefore, the injection devices 101 and 102 and the spacer 5 have a function of injecting or discharging a cutting fluid (and a solidified material) as an injection device.
In addition, about the coupling | bonding of the injection apparatuses 101 and 102 and the spacer 5, it is performed by a well-known technique (for example, adhesion | attachment, a fastening means, etc.).

By interposing the spacer 5 between the injection devices 101 and 102, the vertical interval V between the nozzles N1 and N2 can be adjusted.
For example, if the vertical interval V between the nozzles N1 and N2 when the spacer 5 is not interposed between the injection devices 101 and 102 is the minimum interval (vertical interval) between the nozzles N1 and N2, the injection device 101, When the spacer 5 is interposed between the nozzles 102, the vertical interval between the nozzles N1 and N2 is “V + T”.
Furthermore, a plurality of types of spacers 5 having different thickness dimensions T are prepared, and the range of the vertical interval between the nozzles N1 and N2 can be adjusted as appropriate.

An example of a mechanism for adjusting the vertical spacing V different from FIG. 5 is shown in FIG. In FIG. 6, the vertical interval V is adjusted using a known rack and pinion gear mechanism.
In FIG. 6, the pinion gear 7 has a rotating shaft 7 A attached to an injection device (not shown) and meshes with the rack 6. The rack 6 is fixed to the nozzle N1 and extends parallel to the central axis of the injection device 1 (see FIG. 1). When the rack 6 is moved up and down by rotating the pinion gear 7 forward or backward, the nozzle N1 moves up and down. Thereby, the vertical interval between the nozzles N1 and N2 can be adjusted.

In FIG. 6, an arrow AC indicates the direction of the cutting fluid jet J1.
In FIG. 6, only the nozzle N 1 is configured to move up and down, but only the nozzle N 2 may be fixed to the rack 6 and configured to move up and down. Further, the nozzles N1 and N2 are fixed to different racks, and when the pinion gear 7 rotates, the nozzles N1 and N2 move in the reverse direction in the vertical direction, and the vertical interval V between the nozzles N1 and N2 can be adjusted. Is possible.

According to the illustrated first embodiment, the nozzles N1 and N2 of the injection device 1 are positioned at an interval in the vertical direction, and the cutting fluid jet J1 is injected obliquely downward from the upper nozzle N1, and the lower part By injecting the cutting fluid jet J2 obliquely upward from the nozzle N2, the streamlines of the cutting fluid jet J1 and the cutting fluid jet J2 are in a region on the right side of the injection device 1 in FIG. If there are, there are a plurality of parallel straight lines extending from the upper left to the lower right and a plurality of parallel straight lines extending from the lower left to the upper right.
Therefore, as shown in FIG. 10, the region that is not cut by the cutting fluid jet does not extend in parallel with the streamline of the cutting fluid jet, and the streamline of the other cutting fluid jet is always the cutting fluid jet. Intersects with areas that are not.

That is, even if there is a region that is not cut by the cutting fluid jet at a certain moment, the region is always cut and intersected with one of the cutting fluid jets J1 and J2. For this reason, it is possible to prevent the representative dimension of the region not cut by the cutting fluid jet from becoming large.
As a result, according to the illustrated first embodiment, the maximum soil mass M that can remain without being cut by the cutting fluid jet is more representative than the soil mass M having a large representative dimension shown in FIGS. The size is reduced, and it easily passes through the annular space (see FIGS. 1 and 11) between the injection device 1 and the inner wall surface of the boring hole HD, and does not hinder the discharge of slime to the ground side.

Further, in the illustrated embodiment, the angle θ (injection angle of the cutting fluid jets J1 and J2) at the nozzles N1 and N2 can be adjusted, so that it is efficient in accordance with the type of soil of the construction ground G and the like. It can be adjusted to a proper cutting diameter D.
Further, in the illustrated embodiment, since the vertical interval V between the nozzles N1 and N2 can be adjusted, the jet streamline pitch P shown in FIG. 2 can be adjusted. Therefore, it is possible to adjust the size of the largest soil mass M that can remain without being cut by the jet in accordance with the situation at the construction site.

Next, a second embodiment of the present invention will be described with reference to FIG.
In FIG. 7, the jets J1 and J2 ejected from the nozzle N1 above the ejection device 10 are jetted obliquely downward from the nozzle N1 in the horizontal direction, as described in the first embodiment of FIGS. The jet J2 is jetted from the nozzle N2 obliquely upward in the horizontal direction.
Although not clearly shown in FIG. 7, the jets J 1 and J 2 are jets of a partition forming material in the radially inner (center) portion of the cross section, and a jet of high-pressure air surrounds the periphery thereof. . However, the second embodiment can be implemented without ejecting high-pressure air.
The partition forming material is, for example, a solution containing 5% by weight of a thickener (eg, guar gum which is a natural water-soluble polymer material) and 5% by weight of sodium silicate (water glass). And the separation layer LD is comprised by spraying a partition formation material in soil and mixing with in-situ soil.

On the other hand, the jets J3 and J4 ejected from the lower nozzles N3 and N4 are solidified material jets.
By the jets J3 and J4, the solidifying material is further mixed with the mixture obtained by cutting and mixing the partition forming material and the in-situ soil.
Since the solidified material is injected by the jets J3 and J4 injected from the injection device 10 that is pulled up while rotating, for example, even if the original soil is clay, the mixture of the original soil (clay) and the partition forming material is the solidified material. And mix well.
Here, the mixture of the in-situ soil (clay) and the partition forming material passes as a slime through the annular space S between the injection device 10 and the inner wall surface of the borehole HD as indicated by an arrow AD, to the ground side. Discharged. However, since the mixture of in-situ soil (clay) and partition forming material does not include a solidifying material, it does not need to be treated as industrial waste, and there is little risk of deteriorating the working environment.

As shown in FIG. 7, the partition I is injected by jets J1 and J2 and the ground G is cut to fill the space IJ (original soil, partition forming material) cut by the jets J1 and J2. A separation layer LD is formed in a region above the (space), and the separation layer LD is a solidified material injected from the nozzles N3 and N4 into the annular space S between the injection device 10 and the inner wall surface of the boring hole HD. Acts as a partition to prevent inflow.
Then, by injecting the solidified material with the jets J3 and J4 into the region below the space IJ cut by the jets J1 and J2, the region below the space IJ has a solid compound (solidified material and water and The layer LC of the solidified material having a low ratio W / C is formed.

Here, when the lower jets J3 and J4 collide with the cutting wall W (the inner wall surface of the cutting hole whose diameter has been expanded by cutting with the jets J1 and J2), the lower jets J3 and J4 roll up upward as indicated by an arrow AN. And there exists a possibility that the solidification material may mix in separation layer LD (mixture of the partition formation material which comprises, and the cut soil). If the solidifying material is mixed into the separation layer LD, the solidifying material may be discharged to the ground as a slime.
In order to prevent the solidified material from being discharged to the ground side, when the lower jets J3 and J4 collide with the cutting wall W, the lower jets J3 and J4 need to be rolled down as indicated by an arrow AG. is there. Therefore, as shown in FIG. 7, the lower jets J3 and J4 are directed downward by an angle β with respect to the horizontal direction HO.
In the inventor's experiment, when the jet pressure of the lower jets J3 and J4 is 100 bar, the tilt angle β is 15 °, and when the jet pressure of the jets J3 and J4 is 200 bar, the tilt angle β is 30 °. This is preferable, and the solidification material is prevented from being mixed into the separation layer LD.

According to the second embodiment of FIG. 7, as the injection device 10 is pulled up, the vertical dimension of the solidified material layer LC increases (thickens), and the separation layer LD (partition forming material layer) always solidifies. Move over the layer of material LC.
Since there is a separation layer LD composed of partition forming material, the mixture of partition forming material and soil is discharged to the ground side as slime (mixture of partition forming material and cut soil). The solidified material of rich blend in the layer LC is hardly discharged to the ground side. And since a solidification material is not discharged | emitted on the ground side, waste of a solidification material is suppressed and the generation amount of the slime which should be processed in a special treatment facility as industrial waste decreases.
Further, since the solidified material is injected by the jets J3 and J4 injected from the nozzles N3 and N4 below the injection device 10 and the injection device 10 rises while rotating, even if the viscosity of the in-situ soil is high (for example, clay ), The mixture of in situ soil (clay) and partitioning material is well mixed with the solidification material.

Other configurations and operational effects in the second embodiment of FIG. 7 are the same as those of the first embodiment of FIGS.

It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.
For example, in the illustrated embodiment, two nozzles are provided, but it is possible to provide three or more nozzles as long as they are arranged in a point object with respect to the central axis CL of the injection device.
In the illustrated embodiment, the solidified material is discharged from a discharge port provided below the injection device and discharged into the mixture of the cut in-situ soil and the cutting fluid. Similarly, or together with the cutting fluid jet J, the solidified material may be ejected radially outward.

DESCRIPTION OF

SYMBOLS

1, 10, 11 ... Injection device HC ... Cutting hole HD ... Boring hole IJ ... Cut space J, J1, J2 ... Cutting fluid jet LC ... Solidified material layer LD: Layer of partition forming material (separation layer)
N, N1, N2, N3, N4 ... Nozzle (spray nozzle)
S: Annular space W: Cutting wall (inner wall surface of cutting hole)

Claims

In the ground improvement method of creating a ground consolidated body by injecting cutting fluid from an injection device and cutting, supplying solidified material, mixing and stirring the ground and fluid and solidified material,
A plurality of nozzles are positioned in the injection device at intervals in the vertical direction. When the cutting fluid is injected, the cutting fluid jet is injected obliquely downward from the upper nozzle, and obliquely upward from the lower nozzle. A ground improvement method characterized by injecting a cutting fluid jet.
The ground improvement construction method of Claim 1 which has the process of adjusting the angle of a nozzle.
The ground improvement construction method according to claim 1, further comprising a step of adjusting a vertical interval between the nozzles.