JP2007262652A - Horizontal ground improving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a horizontal ground improving method in which an ordinary hardening agent is available, and a horizontal pipe having a large cross sectional area can be created. <P>SOLUTION: According to the horizontal ground improving method, a lower side portion (71) of the horizontal pile is created in an area (11) lower than the vertical center of a construction target area (10), and an upper side portion (72) of the horizontal pile (to be created) is created after or during creation of the lower side portion (71). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a ground solid body (horizontal) extending in a horizontal direction (in the present invention, the term “horizontal direction” includes a direction inclined with respect to a horizontal plane) at a construction site of the ground improvement method. This is related to the so-called “horizontal ground improvement method”.

  The “horizontal ground improvement method” is performed by, for example, creating a ground solid body (horizontal pile) extending in the horizontal direction in the construction area for the purpose of water stoppage or the like (horizontal on-site pile pile). For example, for water stoppage, a plurality of horizontal piles are adjacent to each other and partly overlapped. FIG. 28 is a diagram showing one step of the horizontal ground improvement method.

  In FIG. 28, the state where the horizontal hole 50 was formed by the cutting means which is not shown in the soil G of a construction area is shown. A solidifying material (for example, grout) 6 is injected into the horizontal hole 50 through the solidifying material injection tube 30. If the injected solidified material 6 is solidified, a ground solid body or a horizontal pile extending in the horizontal direction is created in the soil G.

  Here, the height H of the injected solidified material 6 becomes a problem with respect to the diameter Φ of the horizontal hole 50. That is, the self-supporting height (maximum self-supporting height when the solidifying material is raised on a flat surface that is not constrained around) H of the injected solidified material (discharged from the solidifying material injection pipe 30) is If it is larger than the diameter Φ (state shown in FIG. 28), a region (cavity) where air is accumulated is not formed in the horizontal hole 50 into which the solidifying material 6 has been injected.

Here, when the diameter Φ of the horizontal hole is large (when the diameter Φ exceeds 2 m), or when the clay of the solidified material is low and the self-standing height H is not large, as shown in FIG. The height H is smaller than the diameter Φ of the horizontal hole, and a region (cavity) in which air is accumulated is formed above the horizontal hole 50.
When such a region (cavity) is formed, various inconveniences such as ground subsidence occur, and the quality of the underground consolidated body (horizontal pile) is lowered. Therefore, the self-standing height H of the solidified material 6 needs to be larger than the diameter Φ of the horizontal hole 50.

In order to make the self-supporting height H of the solidifying material 6 larger than the diameter Φ of the horizontal hole 50, it is necessary to use a solidifying material having high clay and high self-supporting properties.
However, when using a solidified material of clay, it is inevitable to use a concrete pump instead of a grout pump. However, when a concrete pump is used, there is a problem that various restrictions occur during construction.
On the other hand, if a solidified material of high clay is supplied as it is with a grout pump, the grout pump burden is large, and the pump life and maintenance of the pump are hindered.

In FIGS. 28 and 29, a horizontal pile having a circular cross-sectional shape is described as an example, but the situation is the same for a horizontal pile having a non-circular cross-sectional shape.
That is, even in a horizontal pile having a non-circular cross section, the self-supporting height H of the solidified material 6 needs to be larger than the height direction dimension of the cross section of the horizontal hole (horizontal pile having a non-circular cross section). It is necessary to use a high solidification material. However, when using a solidified material of clay, there is a problem that it is necessary to use a concrete pump with many restrictions in construction, or to use a grout pump in preparation for shortening the service life or hindering maintenance. To do.

As another conventional technique, a technique for creating a pile having sufficient supporting force in the vertical direction and the horizontal direction has been proposed (see, for example, Patent Document 1).
However, the technology relates to the formation of underground solid bodies (vertical piles) extending in the vertical direction, and the above-mentioned related to the formation of underground solid bodies (horizontal piles) extending in the horizontal direction. It is not possible to solve such problems.
JP 2001-81770 A

  The present invention has been proposed in view of the above-mentioned problems of the prior art, and a horizontal pile having a large height dimension or a large diameter dimension can be created using a normal solidified material that is not high in clay. The purpose is to provide ground improvement methods.

  In the horizontal ground improvement method of the present invention, the lower portion (71) of the horizontal pile is formed in the lower region (11) from the center in the vertical direction of the construction region (10), and after the lower portion (71) is formed. Alternatively, the upper part (72) of the horizontal pile (to be created) is created during construction (claim 1).

  In the present invention, a step of drilling a horizontal boring hole (1) at the center in the vertical direction of the construction area (10) (FIG. 4), and a cutting means (a drilling rod 2 or a boring not shown) from the horizontal boring hole (1). Cutting the lower hole (51) into the lower region (11) by the cutting means (2) while pulling out the rod (FIGS. 5 and 6), and solidifying while cutting the lower hole (51) A step (FIGS. 6 and 7) of forming a lower portion (71) of the horizontal pile by injecting (or filling) the solidified material (6) into the lower hole (51) by the material filling means (31); After forming the lower part (71) of the horizontal pile, the cutting means (2) cuts the upper hole (52) in the upper region (12) (FIG. 7) and the upper hole (52). The solidifying material (6) is put in the upper hole (52) by the solidifying material filling means (31) while cutting. Forming an upper portion of the horizontal pile by entering (72) (FIGS. 7, 8) preferably includes a capital (Claim 2: 1 to 8).

  Alternatively, in the present invention, a step of drilling a horizontal boring hole (1) in the center in the vertical direction of the construction area (10) (FIG. 4), and a cutting means (bore rod 2 or illustrated) from the horizontal boring hole (1). A step (FIG. 5) of cutting the lower hole (51) in the lower region (11) by the cutting means (2) while pulling out the non-boring rod), and the solidified material after cutting the lower hole (51) The step (FIG. 9) of injecting the solidified material (6) into the lower hole (51) by the filling means (31) to form the lower portion (71) of the horizontal pile, and the lower portion (71 of the horizontal pile) ), And then cutting the upper hole (52) in the upper region (12) by the cutting means (2) (FIG. 10), and solidifying material filling means ( 31) inject the solidified material (6) into the upper hole (52) Forming an upper portion (72) (FIG. 11) preferably includes a capital (claim 3: 1-4, 9-11).

  Further, in the horizontal ground improvement method of the present invention, a step of drilling a horizontal boring hole (1) in the vertical center of the construction area (10) (FIG. 4) and a cutting means (cutting rod) from the horizontal boring hole (1). 2 or a step of cutting the lower hole (51) in the lower region (11) by the cutting means (2) while pulling out the boring rod (not shown) (FIGS. 13 and 14), and the lower hole (51 ) While injecting the solidified material (6) toward the lower hole (51) by the solidified material filling means (31A), and cutting the lower hole (51) into the solidified material. Is cut by the cutting means (2) with a delay from the cutting of the lower hole (51) and the injection of the solidified material (by a predetermined time difference: a time corresponding to the distance L in FIG. 13). Cutting the upper hole (52) in the region (see FIG. 6) and a step (FIG. 16) of injecting the solidified material (6) toward the upper hole (52) by the solidified material filling means (31B) while cutting the upper hole (52). (Claim 4: FIGS. 1, 2, 4, 12 to 16).

  In the horizontal ground improvement method of the present invention, the upper portion (72) of the horizontal pile is formed in the upper region (12) from the center in the vertical direction of the construction region (10), and after or after the upper portion (72) is formed. It is characterized in that the lower part (71) of the horizontal pile (to be built) is built in (Claim 5: FIGS. 24 to 27).

In carrying out the present invention, it is preferable to inject a cross jet (Jc) from at least a pair of nozzles (41, 42, 41A, 42A, 41B, 42B) provided in the cutting means (2) during cutting.
When the lower hole (51) is cut, the cross jet (Jc) is preferably constituted by surrounding the high-pressure water jet with a jet of high-pressure air. And when cutting an upper hole (52), it is preferable that a cross jet (Jc) is comprised with a high pressure water jet.

  The cutting means (2) has cross jet injection means (41, 42) using a high-pressure fluid, and the direction of the cross jet (Jc) swings in a semicircular arc in a plane perpendicular to the horizontal direction to be cut. It can be configured to move (see FIG. 2).

  According to the horizontal ground improvement method of the present invention having the above-described configuration, the region where the underground solid body extending in the horizontal direction is to be formed is divided into two upper and lower parts (51, 52) and cut. Each of the two regions or horizontal holes (51, 52) filled with solidification material (6), separately creating a lower part (71) of the horizontal pile and an upper part (72) of the horizontal pile, And an integral horizontal pile (7) can be created with the lower part (71) of the horizontal pile created separately, and the upper part (72) of a horizontal pile. That is, the solidified material (6) filled in the lower hole (51) and the solidified material (6) filled in the upper hole (52) are solidified integrally to form one horizontal pile ( 7) is created.

  Here, according to the present invention, since the lower part (71) of the horizontal pile and the upper part (72) of the horizontal pile are separately formed, the lower part (71) of the horizontal pile and the horizontal pile When each of the upper portions (72) is formed, the required self-supporting height (H) of the solidifying material (6) can be reduced to about ½ that of the prior art. Or, compared with the horizontal ground improvement method according to the prior art in which a solidified material is filled in one horizontal hole, it is possible to construct a horizontal pile having a dimension in the direct direction or a height of about twice.

In the present invention, since the required self-supporting height (H) of the solidifying material (6) can be reduced to about ½ that of the prior art, the underground solid body extending horizontally (horizontal It is not necessary to use a solidified material having a high viscosity even when the cross-sectional area of the pile) or the cross-sectional diameter dimension or height dimension is large.
Since it is not necessary to use a solidified material having a high viscosity, it is possible to use a grout pump without using a concrete pump that causes restrictions on construction. Even when a grout pump is used, unlike the prior art, there is no risk of shortening the life of the grout pump, and there is no risk of inconvenience in maintenance.

  In the present invention, when forming (cutting) the lower horizontal pile (51), the cutting high-pressure fluid (high-pressure water, high-pressure air, etc.) and the solidified material (6) are placed below the borehole (1). Since it is formed by injection, the boring hole (1) is located at the uppermost position of the lower horizontal pile (51), and air or water injected through the uppermost boring hole (1) is used. Alternatively, the slurry can be discharged very easily. Therefore, even when high-pressure air is used when cutting the lower horizontal pile (51), the air is reliably discharged, so a so-called “nest” is formed in the horizontal pile (7) that has been created. There is no end.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 shows a construction area 10 for constructing a horizontal ground improvement method (horizontal pile site casting pile) according to the illustrated embodiment.

In FIG. 1, in the ground G, the construction area | region 10 which should build the underground solidified body (horizontal pile) extended in a horizontal direction is shown enclosed with a dashed-two dotted line.
A boring hole 1 is drilled in the center of the construction area 10 in the vertical direction.

As will be described later, in the embodiment of FIGS. 1 to 11, in constructing the horizontal pile, first, in the region 11 below the boring hole 1, the lower portion of the horizontal pile (reference numeral 71 in FIG. 8). Construction is carried out from (see). Then, after the lower portion of the horizontal pile is formed, the upper portion of the horizontal pile (see reference numeral 72 in FIG. 8) is formed in the region 12 above the boring hole 1.
In other words, in the embodiment shown in FIGS. 2 to 11, the horizontal pile to be constructed (reference numeral 7 in FIG. 8) is formed in a separate process between the lower portion of the horizontal pile and the upper portion of the horizontal pile. Is done.

Here, when the cross-sectional shape of the lower portion and the upper portion of the horizontal pile is a semicircular arc having a radius R (= D / 2: see FIG. 1), the cross-sectional shape of the horizontal pile to be finally created is It becomes a circle with a diameter D.
As will be described later, the cross-sectional shape of the horizontal pile formed by the illustrated embodiment is not limited to a circle, and may be a square or other non-circular shape.

Next, a first embodiment of the present invention will be described with reference to FIGS.
First, an overview of the first embodiment will be described with reference to FIGS.
In the first embodiment, the lower part of the horizontal pile (reference numeral 71 in FIG. 8) is first created, and then the upper part of the horizontal pile (reference numeral 72 in FIG. 8) is created. The horizontal pile 7 is constructed.

FIG. 2 shows that when a horizontal pile is constructed, a cutting rod 2 (cutting means) used for cutting a digging cut (a hole extending in the horizontal direction) having the same contour as the horizontal pile to be constructed is a boring hole. 1 shows a state of being inserted.
As shown in (2-1) of FIG. 2, a solidified material (for example, grout) supply line 3 and a cutting fluid supply line 4 are disposed inside the cutting rod 2.

  The tip of the solidifying material supply line 3 communicates with a solidifying material injection port 31 formed at the tip of the cutting rod 2 (the right end in FIG. 2 (2-1)). A first nozzle 41 and a second nozzle 42 are formed at a location separated from the tip of the cutting rod 2 by a predetermined distance. The nozzles 41, 42 communicate with the cutting fluid supply line 4, and the nozzles 41, 42 are separated from each other in the longitudinal position of the cutting rod 2 by a predetermined distance.

  The jet directions of the nozzles 41 and 42 are such that the jets J1 and J2 of the fluid (high pressure fluid: high pressure water, for example) jetted from the nozzles 41 and 42 are at a distance (radial distance) R from the central axis of the cutting rod 2. It is set to cross each other. That is, the nozzles 41 and 42 are configured such that a high-pressure fluid jet ejected therefrom forms a so-called “cross jet” Jc.

  Here, when cutting the lower region of the boring hole 1, the jets J1 and J2 of the fluid ejected from the nozzles 41 and 42, for example, surround the high-pressure water jet with high-pressure air. It is preferable. This is because the soil cutting ability of the jets J1 and J2 is improved, the reach distance in the ground is lengthened, and the formation of an underground solid body having a large cross-sectional area is possible.

In the embodiment of the present invention (including embodiments other than the first embodiment), the cutting rod 2 is configured to reverse the rotation direction every time it rotates by a half rotation (180 °). In other words, the cutting rod 2 is configured to swing 180 °.
As a result, the cross jet Jc injected from the cutting rod 2 draws a semicircular arc in a plane orthogonal to the cutting direction, as shown in (2-2) of FIG.

Here, the reach distance R in the ground of the intersecting jet Jc can be kept constant, or can be changed during the injection.
If the distance R is constant, a horizontal hole having a semicircular cross section is formed (a horizontal pile having a circular cross section is formed by being vertically aligned).
On the other hand, if the reach distance R is changed during the injection of the cross jet Jc while swinging the cutting rod 2, a horizontal hole having a non-circular cross section (for example, a rectangular cross section) is formed as described later with reference to FIG. It is also possible to form.

FIG. 3 is a diagram representing the first embodiment, and in FIGS. 4 to 8 showing a series of steps in the first embodiment, a construction state in the same step as the step shown in FIG. 7 is shown.
In FIG. 3, the ground G including the region (reference numeral 10 in FIG. 1) in which a horizontal pile is to be formed has already been drilled, and the inside of the (boring hole 1) is a cutting means. A cutting rod 2 is inserted.

In the state shown in FIG. 3, a horizontal hole (lower water side hole) 51 having the same contour as that of the lower portion 71 of the horizontal pile is already cut below the bored hole 1 by the cutting rod 2 and cut. The entire area of the side hole 51 is filled with a solidifying material 6 (for example, grout).
That is, in the state shown in FIG. 3, the lower portion 71 of the horizontal pile to be formed has already been formed (created).

  In the state shown in FIG. 3, the cutting injection nozzles 41 and 42 of the cutting rod 2 face upward. High-pressure fluid jets J1 and J2 are jetted from the cutting jet nozzles 41 and 42 to form a cross jet Jc. And the horizontal hole (upper hole) 52 of the same outline as the upper part 72 (refer FIG. 8) of a horizontal pile is cut on the upper side of the boring hole 1 by the cross jet Jc.

In FIG. 3, the solidified material 6 is filled in the upper hole 52 during cutting.
At the stage where the upper hole 51 of the horizontal pile is cut by the cross jet Jc or the upper hole 52 is cut, the cut space is filled with muddy water. By filling the solidified material 6 in the space filled with the muddy water, the solidified material 6 is replaced with the muddy water, and the hole 51 or the hole 52 is filled with the solidified material.

Next, the steps of the first embodiment will be described step by step with reference to FIGS.
First, in the first step of FIG. 4, the boring hole 1 is drilled in the ground G including the construction area with a boring rod (not shown). A cutting rod 2 is inserted into the boring hole 1.

Then, high-pressure water jets J1 and J2 are jetted from the nozzles 41 and 42 of the cutting rod 2 to cut the ground in the lower region of the boring hole 1. Here, the high-pressure water jets J1 and J2 are surrounded by high-pressure air (or covered with high-pressure air).
As described above, the high-pressure water jets J1 and J2 covered with the high-pressure air intersect each other at a point where the distance from the central axis of the cutting rod 2 is R to form an intersecting jet Jc. The region outside in the radial direction is not cut from the cut portion. As a result, the area where the underground solid body (horizontal pile) should be created can be accurately cut into a predetermined dimension.

  In the process shown in FIG. 5, the cutting rod 2 is directed downward from the horizontal plane (horizontal plane extending in the direction perpendicular to the paper surface of FIG. 5) including the central axis of the cutting rod 2 in the direction of the cross jet Jc. Further, the cutting rod 2 is pulled out in the direction of the arrow Y while the nozzles 41 and 42 are inverted by 180 ° and repeatedly swung (2-2 in FIG. 2). Thereby, the hole 51 whose cross section is a semicircular arc is formed by the trajectory of cutting by the cross jet Jc.

In the process of FIG. 6, from the time when the lower hole 51 is cut by a predetermined distance in the axial direction of the cutting rod 2, the solidified material (for example, grout: other Solidified material) may be filled in the lower holes 51 filled with muddy water.
Here, the solidified material to be filled can be of a normal viscosity even when a large-diameter underground consolidated material is formed.

  In the process of FIG. 7, the entire lower hole 51 is filled with the solidified material 6 to form the lower portion 71 of the horizontal pile. On the upper surface of the lower portion 71 of the horizontal pile, the cutting rod 2 is reinserted into the place where the boring hole 1 was drilled in FIG. Then, the lower hole 51 is cut to form the lower part 71 of the horizontal pile, and the upper hole 52 is cut to form the upper part 72 of the horizontal pile.

Here, when the upper hole 52 is cut, it is difficult to remove air, and there is a risk that air may accumulate upward (a so-called “nest” is formed), so the high-pressure water jet that forms the cross jet Jc. Do not surround with high-pressure air. That is, when the upper hole 52 is cut, the jets J1 and J2 are high-pressure water jets, and high-pressure air is not injected.
Moreover, cutting of the upper part and filling of the solidified material 6 are possible even before the solidified material 6 of the lower part is completely solidified. By cutting the upper portion and filling the solidified material 6 before the solidified material 6 in the lower portion is completely solidified, the construction period can be shortened.

  FIG. 8 shows a state in which the horizontal pile 7 is formed (placed) by the solidified material 6 filled with the lower portion 71 and the upper portion 72 of the horizontal pile, and is formed.

Next, a modification of the first embodiment will be described with reference to FIGS.
3 to 8, the horizontal holes 51 and 52 are filled with the solidified material 6 in the middle of cutting the lower hole 51 and the upper hole 52.
On the other hand, in the modified examples of FIGS. 9 to 11, after the formation of the lower hole 51 is finished, the solidified material 6 is filled in the lower hole 51. Then, after the formation of the upper hole 52 is finished, the upper hole 52 is filled with a solidifying material.

FIG. 9 shows a process in which the solidified material 6 is filled in the lower hole 51 that has already been cut and filled with muddy water. As in the first embodiment, the solidified material may be injected via the solidified material supply line 3 (not shown in FIG. 9) and the solidified material injection port 31 provided on the cutting rod 2, or In addition to the cutting rod 2, a rod (not shown) dedicated to filling the solidifying material may be used.
When injecting (or filling) the solidifying material, from the front end side (right end side in FIG. 9) of the lower hole 51 toward the opening side (left side in FIG. 9; the opening is not shown). The solidification material is injected. This is to prevent an air reservoir (so-called “nest”) from being formed on the tip side of the excavated hole 51.

FIG. 10 shows a process of forming the upper hole 52 by the intersecting jet Jc of the cutting rod 2 after filling the lower portion 71 of the horizontal pile with the solidification material.
FIG. 11 shows a process in which the upper hole 52 is filled with the solidified material 6 after the upper hole 52 has been cut.
Except for the above, the configurations and operational effects of the modified examples of FIGS. 9 to 11 are generally the same as those of the first embodiment.

According to the first embodiment described above, first, the lower hole (horizontal hole) 51 is cut, and the lower hole 51 is filled with the solidifying material simultaneously with or after the cutting, and then the upper hole is filled. One horizontal pile 7 is formed by cutting 52 and filling the solidified material 6. As a result, the self-supporting height H (see FIGS. 28 and 29) required at the time of filling or injecting the solidifying material 6 can be reduced to half that when a horizontal pile having the same cross section is constructed by the conventional technique.
Alternatively, when a solidified material having the same viscosity or self-standing height H is used, it is possible to create a horizontal pile 7 having a height (or diameter) approximately twice that of a conventional horizontal pile. .

  Here, when cutting the area on the lower half side of the ground solid body or horizontal pile (cutting the hole 51), since the boring hole 1 is at the top of the hole 51, air, slurry, etc. It can be easily discharged through the boring hole 1.

Next, a second embodiment will be described with reference to FIGS.
In the second embodiment, the nozzles 41A, 42A (for the lower side), 41B, 42B (for the upper side), which are different on the lower side and the upper side, and the solidifying material inlet 31A (for the lower side) which are different on the lower side and the upper side are used. , 31B (for upper side) is inserted into the boring hole 1, and cutting of the upper hole 52 and upper side for cutting of the lower hole 51 and filling of the solidified material 6 into the lower hole In this embodiment, the filling of the solidified material 6 into the holes 52 is slightly delayed (with a time difference).

That is, in the second embodiment, as shown in FIG. 12, the lower hole 51 is cut, the solidified material 6 is filled into the lower hole, the upper hole 52 is cut, and the upper hole 52 is cut. There is a process in which the solidifying material 6 is simultaneously filled.
Here, in the example of FIG. 12, upper cross jet nozzles 41 </ b> B and 42 </ b> B and a solidifying material inlet 31 </ b> B are provided on the distal end side of the cutting rod 20.

  FIG. 12 is a diagram representing the second embodiment. In the case of construction according to the second embodiment, intermediate steps (in FIG. 16 among FIGS. 13 to 16 which are a series of process diagrams in the second embodiment). The process is substantially the same as the process shown).

  In the step shown in FIG. 12, the lower hole 51 is cut and the solidified material 6 is filled into the lower hole 51. At the same time, the upper hole 52 is cut and the upper hole 52 is filled. Filling of the solidifying material 6 is performed. However, the cutting of the upper hole 52 is delayed by a predetermined time compared to the cutting of the lower hole 51 (the right region in FIG. 12 is cut), and the lower hole 51 is cut. Compared with the filling of the solidified material 6 into the filling, the filling of the upper hole 52 is also delayed by a predetermined time (the right region in FIG. 12 is filled).

Next, the steps of the second embodiment will be described step by step with reference to FIGS.
First, in the first step of FIG. 13, the boring hole 1 is drilled in the ground G including the construction region 10 by a boring rod (not shown), and the cutting rod 20 is inserted to the tip of the boring hole 1.

As described above, the cutting rod 20 includes the nozzles 41A and 42A for cutting the lower hole 51 and the solidifying material injection port 31A for injecting or filling the solidifying material into the lower hole 51. In addition, nozzles 41B and 42B for cutting the upper hole 52, and a solidifying material injection port 31B for injecting or filling the solidifying material into the upper hole 52 are provided.
The nozzles 41A and 42A and the nozzles 41B and 42B are separated by a distance corresponding to the above-described time difference (the time during which the construction in the upper hole 52 is delayed with respect to the lower hole 51: a predetermined time). ing. Similarly, the solidifying material inlet 31A and the solidifying material inlet 31B are also separated by a distance corresponding to the above-described time difference.

  In the process of FIG. 14, the lower hole 51 is cut by the cross jet Jc, but the upper hole (reference numeral 52 in FIG. 12) is not cut. Here, in FIGS. 13 and 14, an arrow indicated by a dotted line indicates that the jet is not being ejected at that time.

In the step shown in FIG. 15, the solidifying material 6 is injected or filled into the lower hole 51 from the solidifying material injection port 31 </ b> A for the lower hole 51.
In the process of FIG. 16, the upper hole 52 is cut by the cross jet Jc after a predetermined time delay from the start of cutting of the lower hole 51 (see FIG. 13). Here, at the time shown in FIG. 16, the cutting of the upper hole 52 has progressed to some extent, and the filling of the solidified material 6 into the upper hole 52 has started.
Thereafter, as shown in FIG. 16, cutting and injection of the solidified material are performed in the upper hole 52 and the lower hole 51 until the horizontal pile is completed.

  Next, a modification of the second embodiment will be described with reference to FIGS. In the second embodiment of FIGS. 12 to 16, in order to perform construction with a time lag between the lower side and the upper side, the cutting rod 20 becomes longer and the boring hole 1 has to be drilled longer. There's a problem. That is, the drilling distance of the boring hole 1 must be excavated longer by the length of the cutting rod 20 (by the distance corresponding to the time delay) than the length of the region where the horizontal pile should be formed. is there.

  In the modification of the second embodiment of FIGS. 17 to 20, in order to solve this problem, the upper construction cutting rod 22 is nested so that it can be accommodated inside the lower cutting rod 21. Therefore, the boring distance of the boring hole 1 is not required to be long.

  In FIG. 17, cutting nozzles for cutting the lower hole 51 (see FIG. 18) are denoted by reference numerals 41 </ b> C and 42 </ b> C, and a solidifying material inlet for injecting the solidifying material into the lower hole 51. Is indicated by reference numeral 31C. The nozzles 41C and 42C and the solidifying material injection port 31C are both on the lower end side of the cutting rod 21 (the tube outside the double tube shown in FIG. 17) for cutting the lower hole 51. It is provided facing the side.

  On the other hand, cutting nozzles for cutting the upper hole 52 (see FIG. 20) are denoted by reference numerals 41D and 42D, and a solidifying material inlet for injecting the solidifying material into the upper hole 52 is denoted by 31D. It is shown. The nozzles 41D and 42D and the solidifying material inlet 31D are arranged on the distal end side of the nesting cutting rod 22 for the upper hole 52 (the inner pipe of the double pipe shown in FIG. 17) 22 in FIG. Both are provided facing upward.

  Here, the telescopic cutting rod 22 for the upper hole 52 is lowered by a known means such as a hydraulic cylinder or a spring (not shown) at a stage where the upper hole 52 is not cut or filled with a solidified material. It is configured to be accommodated in the cutting rod 21 for the side hole 51.

Next, the process of the modification of 2nd Embodiment is demonstrated in order with reference to FIGS.
First, in the process of FIG. 18, the telescopic cutting rod 22 used in the upper hole 52 is still housed in the cutting rod 21 for the lower hole 51. In this state, the lower hole 51 is cut, and the solidified material 6 is filled into the cut lower hole 51.

  In the stage shown in FIG. 18, as described above, the telescopic cutting rod 22 remains in the cutting rod 21 (the rod for the lower hole 51) and is formed on the telescopic cutting rod 22. No high pressure water jet is ejected from the nozzles 41D and 42D. Similarly, the solidified material is not injected from the solidified material injection port 31D formed in the telescopic cutting rod 22.

When the cutting operation of the lower hole 51 and the filling operation of the solidified material 6 into the lower hole 51 proceed and the state shown in FIG. 19 is reached, the nested cutting rod 22 used for the upper hole 52 is It expands and is exposed from the rod 21 for the lower hole 51, and a high-pressure water jet is ejected from the nozzles 41 </ b> D and 42 </ b> D formed on the telescopic cutting rod 22, and the upper hole 52 is cut. .
However, in the stage of FIG. 19, the solidified material is not injected from the solidified material injection port 31D.

When the cutting operation and the solidifying material filling operation further progress and reach the stage shown in FIG. 20, the telescopic cutting rod 22 used for the upper hole 52 is further extended, and the solidifying material injection port 31 </ b> D is cut. It is exposed in the hole 52. Then, the solidified material is filled into the upper hole 52 from the solidified material inlet 31D.
As a result, the formation of the lower portion 71 of the horizontal pile and the formation of the upper portion 72 of the horizontal pile are performed simultaneously.

  According to the second embodiment of the construction method, the start of construction in the upper hole 52 is delayed from the construction in the lower hole 51, but the construction on the lower hole 51 side and the construction on the upper hole 52 side are simultaneously performed. Since it is performed, the construction period can be further shortened compared to the first embodiment.

In the illustrated embodiment, the cross-sectional shape of the horizontal pile is described as a circular shape (combination of the lower semicircular cross section and the upper semicircular cross section). However, as shown in FIGS. It is possible to create a horizontal pile having a non-circular cross section, that is, a quadrangular cross section in FIGS.
In the case where a horizontal pile having a non-circular cross section, for example, a quadrangular cross section, is constructed, it is preferable for eliminating waste of construction and performing water stop perfectly. The reason will be described later with reference to FIG.

In FIG. 21, one horizontal pile 7 is formed by drilling one boring hole 1 and constructing the lower portion 71 and the upper portion 72 separately (with a delay in time) therefrom.
On the other hand, in FIG. 22, first, the lower portion 71 of the horizontal pile is formed by one boring hole 1A, and further, the boring hole 1B is formed at the same height as the lower portion 71 of the horizontal pile. This is a type in which one horizontal pile 7 is formed by drilling, forming an upper portion 72 of the horizontal pile between the upper boring hole 1B and the lower boring hole 1A.
The embodiment of FIG. 21 is superior to the embodiment of FIG. 22 in that the boring hole 1 only needs to be drilled once. However, in the present invention, the construction as shown in FIG. 22 can be included. Appendices.

Next, with reference to FIG. 23, an advantage of the horizontal pile having the non-circular cross section over the horizontal pile having the circular cross section will be described.
As shown in FIG. 23A, the horizontal piles 7 having a circular cross section must partially overlap the adjacent horizontal piles 7 in order to make the water stop perfect. However, the overlapped portion 7d is subjected to useless construction.

On the other hand, the horizontal pile 7 (example of FIG. 21, FIG. 22) of the rectangular cross section containing a square does not need to pile up adjacent piles 7, as shown to (B) of FIG. That is, it is not necessary to construct a useless part like the part 7d in FIG. 23A, and useless cost can be eliminated. In that respect, it is more advantageous than the circular cross section shown in FIG.
Here, although the horizontal pile which has a rectangular cross section is illustrated in FIG.23 (B), even if it is other non-circular cross sections, such as a triangle and a hexagon, adjacent horizontal piles are piled up similarly to a quadrangle. There is no need.

Next, a third embodiment of the present invention will be described with reference to FIGS.
First, in the first step of FIG. 24, the boring hole 1 is drilled in the ground G including the construction area with a boring rod (not shown).
The cutting rod 2 is inserted into the boring hole 1 and jets of high-pressure water J1 and J2 are ejected from the nozzles 41 and 42 of the cutting rod 2 to cut the ground in the region above the boring hole 1.

Here, the high-pressure water jets J1 and J2 intersect each other at a point where the distance from the central axis of the cutting rod 2 is R to form an intersecting jet Jc.
When cutting the upper hole 52 (see FIGS. 25 to 27), it is difficult to remove air, and there is a risk that air may accumulate upward (so-called “nest” is formed). Individual high-pressure water jets are not surrounded by high-pressure air. That is, when the upper hole 52 is cut, the jets J1 and J2 are high-pressure water jets, and high-pressure air is not injected.

  In the process of FIG. 25, the cutting rod 2 is placed in a state in which the direction of the intersecting jet Jc faces upward from a horizontal plane (horizontal plane perpendicular to the paper surface of FIG. 25) including the central axis of the cutting rod 2. The cutting rod 2 is pulled out in the direction of the arrow Y while reversing around the central axis by 180 ° and repeatedly rocking. Thereby, the upper hole 52 having a semicircular cross section is formed by the trajectory of cutting by the intersecting jet Jc.

From the time when the upper hole 52 is cut by a predetermined distance in the axial direction of the cutting rod 2, the solidified material enters the upper hole 52 filled with muddy water from the solidified material inlet 31 at the tip of the cutting rod 2. 6 is filled (FIG. 26).
Here, since the solidified material 6 is filled only in the upper hole 52, even if the cross-sectional area of the underground solid body (horizontal pile) extending in the horizontal direction finally formed is large. It is not necessary to use a solidified material having a high viscosity. Those having a normal viscosity can be used.

If the entire upper hole 52 is filled with the solidified material 6 and the upper portion 72 of the horizontal pile is formed, as shown in FIG. 27, the boring hole 1 is drilled in the lower surface of the upper portion 72 of the horizontal pile. The cutting rod 2 is inserted again into the place (see FIG. 24).
Then, the upper hole 52 is cut (see FIGS. 24 and 25), and the lower hole 51 is cut by the same method as that for forming the upper portion 71 of the horizontal pile (see FIGS. 25 and 26). And the lower part 71 (refer FIG. 8) of a horizontal pile is formed.

Here, when the upper hole 52 is cut, it is difficult to remove air, and there is a possibility that air may accumulate upward (so-called “nest” may be formed), and therefore, the high-pressure water jet constituting the cross jet Jc. Is not surrounded by high pressure air.
On the other hand, when cutting the lower portion and filling the solidified material 6, air can be discharged through the boring hole into which the excavating rod 2 is inserted, so that the high-pressure water jet constituting the intersecting jet Jc It can be surrounded by high-pressure air.

  Cutting of the lower part and filling of the solidified material 6 is possible even before the solidified material of the upper part is completely solidified. Then, by cutting the lower portion and filling the solidified material 6 before the solidified material 6 in the upper portion is completely solidified, the construction period can be shortened.

  The illustrated embodiment is merely an example, and does not limit the technical scope of the present invention.

Sectional drawing explaining the construction area | region in connection with embodiment of this invention. The figure which shows the side view and cutting mode of the cutting rod used for embodiment of this invention. Sectional drawing which caught 1 process of 1st Embodiment in this invention characteristically. The 1st process drawing of a 1st embodiment. 2nd process drawing of 1st Embodiment. 3rd process drawing of 1st Embodiment. 4th process drawing of 1st Embodiment. The 5th process drawing of a 1st embodiment. The 1st process drawing of the modification of a 1st embodiment. The 2nd process drawing of the modification of a 1st embodiment. The 3rd process drawing of the modification of a 1st embodiment. Sectional drawing which caught 1 process of 2nd Embodiment in this invention characteristically. The 1st process drawing of a 2nd embodiment. The 2nd process drawing of a 2nd embodiment. 3rd process drawing of 2nd Embodiment. 4th process drawing of 2nd Embodiment. The fragmentary sectional view of the cutting rod used in the modification of a 2nd embodiment. The 1st process drawing of the modification of a 2nd embodiment. The 2nd process drawing of the modification of a 2nd embodiment. The 3rd process drawing of the modification of a 2nd embodiment. Sectional drawing of the horizontal pile of a square cross section. Sectional drawing of the horizontal pile of the square cross section constructed in the aspect different from FIG. The figure which compares and shows the some horizontal pile which has a circular cross section, and the some horizontal pile which has a non-circular cross section. The 1st process drawing of a 3rd embodiment. The 2nd process drawing of a 3rd embodiment. The 3rd process drawing of a 3rd embodiment. 4th process drawing of 3rd Embodiment. Sectional drawing when the solidification material is filled over the entire diameter of the cutting hole in the conventional method. Sectional drawing which shows the state which the clearance gap produced above the cutting hole, when the solidification material is soft and the self-supporting height is insufficient in the conventional construction method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Boring hole 2 ... Cutting rod 3 ... Solidification material supply line 4 ... Cutting fluid supply line 6 ... Solidification material / solidification material 31 ... Solidification material inlet 41 ... No. 1 nozzle 42 ... second nozzle 51 ... lower hole 52 ... upper hole 71 ... lower part 72 of horizontal pile ... upper part G of horizontal pile ... ground Jc: Cross jet

Claims (5)

  A horizontal ground improvement method characterized in that a lower part of a horizontal pile is created in a region below the center in the vertical direction of the construction area, and an upper part of the horizontal pile is created after or during construction of the lower part. .   Drilling a horizontal boring hole in the vertical center of the construction area, cutting the lower hole in the lower area by the cutting means while pulling the cutting means from the horizontal boring hole, and cutting the lower hole While solidifying material is injected into the lower hole by the solidifying material filling means and the lower part of the horizontal pile is created, and after the lower part of the horizontal pile is created, the upper hole is formed in the upper region by the cutting means. The horizontal ground improvement construction method of Claim 1 including the process of inject | pouring a solidification material into an upper hole by a solidification material filling means, and forming the upper part of a horizontal pile, cutting the upper hole, and cutting an upper hole.   A step of drilling a horizontal boring hole in the vertical center of the construction area, a step of cutting a lower hole in a lower region by the cutting means while pulling the cutting means from the horizontal boring hole, and a lower hole was cut. Later, the solidifying material is injected into the lower hole by the solidifying material filling means to form the lower portion of the horizontal pile, and after the lower portion of the horizontal pile is formed, the upper hole is formed in the upper region by the cutting means. The horizontal ground improvement construction method of Claim 1 including the process of inject | pouring a solidification material into an upper hole by a solidification material filling means after cutting an upper hole, and forming the upper part of a horizontal pile after cutting an upper hole.   Drilling a horizontal boring hole in the vertical center of the construction area, cutting the lower hole in the lower area by the cutting means while pulling the cutting means from the horizontal boring hole, and cutting the lower hole While injecting the solidified material toward the lower hole by the solidifying material filling means and cutting the lower hole and injecting the solidified material, the cutting of the lower hole and the injection of the solidified material are delayed. The horizontal ground according to claim 1, further comprising: cutting the upper hole in the upper region by the cutting means; and injecting the solidified material toward the upper hole by the solidifying material filling means while cutting the upper hole. Improved construction method.   A horizontal ground improvement method characterized in that an upper part of a horizontal pile is created in an upper area from the center in the vertical direction of the construction area, and a lower part of the horizontal pile is created after or during construction of the upper part.

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