JP2003239668A - Shaft excavation method and its device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shaft excavation method and its device capable of excavating a shaft while adjusting a clearance between the shaft and a bedrock with high degree of accuracy. <P>SOLUTION: In the shaft excavation method for excavation a shaft (3) by a high pressure jet (J1) jetted from a vertical nozzle (2) provided to the casing end face (1a), the vertical nozzle (2) jets the high pressure fluid jet (J1) in the vertical direction, and the high pressure jet (J1) jetted in the vertical direction excavates soil while widening it so that the necessary clearance (δ) can be obtained. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical hole excavation method and apparatus for injecting a high-pressure fluid jet such as high-pressure water from a nozzle provided on an end surface of a casing, and excavating a vertical hole in a construction ground by the high-pressure fluid jet. .

[0002]

2. Description of the Related Art In carrying out the above-described vertical hole excavation method and apparatus, it is necessary to discharge a slurry which is a mixture of an injected fluid (for example, water) and soil cut or excavated by the fluid.

When a flow path for discharging the slurry is provided in the casing, the flow path may be blocked by the slurry itself, and it is desirable to form the flow path for discharging the slurry on the outer peripheral portion of the casing. Further, if the inner diameter of the excavated vertical hole and the outer diameter of the casing match, it may be difficult to insert the casing into the ground.

For the above reasons, when excavating vertical holes,
The necessary amount of "clearance with the ground" (hereinafter referred to as "clearance") is maintained so that the inner diameter of the excavation hole (standing hole) is slightly larger than the outer diameter of the casing. In other words, the dimension represented by the symbol “δ” in FIG. 1 is the “clearance” in this specification. Here, since the "clearance" is very small (for example, about 10 mm), it is very difficult to control the numerical value.

If the clearance is small, it becomes difficult to insert the casing as described above, and the cross-sectional area of the slurry discharge passage formed on the outer peripheral portion of the casing becomes small, so that the slurry flows to the ground side. Emissions may be inadequate.

On the other hand, if the clearance is large, the cross-sectional area of the excavated vertical hole becomes larger than the cross-sectional area of the casing, so that the inserting direction of the casing may be inclined with respect to the vertical axis.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been proposed to solve the above-mentioned problems of the prior art,
It is an object of the present invention to provide a vertical hole excavation method and apparatus that enable excavation of a vertical hole while adjusting the clearance with high accuracy.

[0008]

According to the vertical hole excavation method of the present invention, a vertical nozzle (2) provided on a casing end surface (1a).
In the vertical hole excavation method of excavating the vertical hole (3) by the high pressure jet (J1) jetted from the vertical nozzle (2), the high pressure fluid jet (J1) is vertically jetted and jetted vertically. The high-pressure jet (J1) is characterized by excavating the soil while expanding so as to secure the necessary clearance (δ) (claim 1).

In order to carry out such a vertical hole excavating method, the vertical hole excavating device (A) of the present invention includes a casing (1) having a vertical nozzle (2) provided on an end face (1a) thereof, and the vertical nozzle (2) is provided. ) Is configured to eject a high-pressure fluid jet (J1) in the vertical direction, and the required clearance (δ)
It is characterized in that it is arranged at a position where it can be secured (Claim 4).

The jet (J1) of high-pressure fluid (for example, high-pressure water) jetted from the nozzle (2) does not jet with the same outer diameter and the same cross-sectional area as the inner diameter of the nozzle even if it is separated from the nozzle (2). , The cross-sectional area increases slightly as the distance from the nozzle (2) increases.

On the other hand, the pressure of the jet flow (J1) is set to the nozzle (2).
Uniaxial compressive strength σ (for example, σ = 1 kg / cm) of soil in which the jet pressure diminishes rapidly as it separates from
² ) In the following cases, the soil cannot be excavated. Here, the pressure of the jet flow is highest at the center line and becomes lower outward in the radial direction. As a result, the high-pressure fluid jet (J1) ejected from the nozzle (2) has a larger cross-sectional area as it is farther from the nozzle (2). The cross-sectional area decreases as the distance from (2) increases. That is, the cross-sectional area of the high-pressure fluid jet (J1) jetted from the nozzle (2) becomes maximum at the point of the certain distance.

Therefore, according to the present invention, by preliminarily analyzing the jet cross-sectional area (that is, the maximum cross-sectional area of the high-pressure fluid jet J1) at the "constant distance", the high-pressure fluid jet at the maximum cross-sectional area ( The arrangement of the nozzles (2) and the high-pressure fluid jet (J1) are adjusted so that the outer peripheral portion of J1) reaches a position protruding outward from the casing (1) by a required clearance (δ). This allows
It is possible to excavate the vertical hole (3) while ensuring the required clearance (δ).

In the vertical hole excavation method of the present invention, the vertical hole (2) provided on the casing end face (1a) and the high pressure fluid jets (J1, J2) injected from the inward nozzle (4) are used to form the vertical hole (3). ), The vertical nozzle (2) ejects a high-pressure fluid jet (J1) in the vertical direction, and the high-pressure fluid jet (J1) ejected in the vertical direction has a required clearance (δ). The pressure is attenuated while expanding so as to be secured, and the high-pressure fluid jet (J2) jetted from the inward nozzle (4) crosses the extension line of the central axis (CL) of the casing (1) to the vertical nozzle (2). ) And the high-pressure fluid jet (J1) colliding with the high-pressure fluid jet (J1) ejected from the inward nozzle (4) and the high-pressure fluid jet (J1) ejected from the vertical nozzle (2).
The collision position (S) with the vertical nozzle (2) is below the position (T) where the pressure of the high-pressure fluid jet (J1) is equal to the uniaxial compressive strength of the soil (G). It is characterized (Claim 2).

In order to carry out such a vertical hole excavating method, the vertical hole excavating apparatus (A) of the present invention has a casing (1) provided with a vertical nozzle (2) and an inward nozzle (4) on an end face (1a). ), The vertical nozzle (2) is configured to eject a high-pressure fluid jet (J1) in the vertical direction,
The nozzle (4) is arranged at a position where a necessary clearance (δ) can be secured, and the high pressure fluid jet (J2) injected from the inward nozzle (4) is on an extension line of the central axis (CL) of the casing (1). Across the vertical axis (2), and the pressure of the high-pressure fluid jet (J1) ejected from the vertical nozzle (2) is arranged so as to collide below the position (T) at which the uniaxial compressive strength of the soil (G) becomes equal. (Claim 5).

According to the above structure, the high-pressure fluid jet (J1) jetted from the vertical nozzle (2).
And the high-pressure fluid jet (J2) jetted from the inward nozzle (4) constitutes a so-called "cross jet". Therefore, the high pressure fluid jet (J1, J2) is not excavated vertically downward and radially outward from the collision point.

Here, the "position (T) at which the pressure of the high-pressure fluid jet (J1) injected from the vertical nozzle (2) becomes equal to the uniaxial compressive strength of the soil (G)" is the vertical nozzle (2).
It is none other than the position where the cross-sectional area of the high-pressure fluid jet (J1) jetted from is maximum. The cross-sectional area of the high-pressure jet (J1) decreases in the region vertically below it.
Therefore, the book configured to "impact below the position (T) where the pressure of the high-pressure fluid jet (J1) injected from the vertical nozzle (2) becomes equal to the uniaxial compressive strength of the soil (G)" According to the invention, the soil (G) radially outside the maximum cross-sectional area of the high-pressure fluid jet (J1) ejected from the vertical nozzle (2) is not excavated.

Further, according to the above-mentioned structure, since the high pressure fluid jet (J2) jetted from the inward nozzle (4) excavates the entire region corresponding to the projected area of the casing (1), the casing ( 1) The inconvenience that the vertical nozzle (2) and the inward nozzle (4) come into contact with the soil (G) and are damaged during insertion is prevented.

In addition to this, in the vertical hole excavation method of the present invention, the vertical nozzles (2-A, 2) provided on the end face (1b) of the casing are used.
-B) and the high pressure jets (J1-A, J1-B, J2-A, J2-) jetted from the inward nozzles (4-A, 4-B).
In the vertical hole excavation method of excavating the vertical hole (3) by B), the vertical nozzle (2-A, 2-B) ejects a high-pressure fluid jet (J1-A, J1-B) in the vertical direction, The high-pressure fluid jets (J2-A, J2-B) jetted from the inward nozzles (4-A, 4-B) cross the extension line of the central axis of the casing (1b) and the vertical nozzles (2-A, J-A). 2-
B) High-pressure fluid jets (J1-A, J1-
B), and after the collision, the high-pressure fluid jet (J2-A, J2
-B: However, when the collision angle is relatively small, the jet J1-
The necessary clearance (δ) is secured by the energy remaining in the combined jet of A, J1-B, J2-A, and J2-B (claim 3).

Further, the vertical hole excavating device of the present invention comprises a vertical nozzle (2-
A, 2-B) and inward nozzles (4-A, 4-B) are provided, and the vertical nozzles (2-A, 2-B) are vertically high-pressure fluid jets (J1-A, J1-B). And the inward nozzles (4-A, 4-B) are there (inward nozzle 4
-A, 4-B) a high-pressure fluid jet (J2-
A, J2-B) collide with the high pressure fluid jet (J1-A, J1-B) jetted from the vertical nozzles (2-A, 2-B) across the extension of the central axis of the casing (1b). Then
After the collision, the high-pressure fluid jet (J2: However, when the collision angle is relatively small, the jets J1-A, J1-B, J2-A, J2
It is configured to excavate the required clearance (δ) by the energy remaining in the (-B composite jet flow) (claim 6).

According to the present invention having such a structure, the high-pressure fluid jet (J2) (injected from the inward nozzle 4) having the function of excavating the required clearance (δ) is projected on the casing (1b). Since approximately the entire area is excavated and collides with the high-pressure fluid jet (J1) ejected from the vertical nozzle (2), the energy remaining after the collision becomes extremely small. Therefore, there is no fear that the excavation clearance (δ) will become too large due to the remaining energy, and the straightness of the excavation casing will not be impeded.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS. In FIGS. 1 and 4, a casing 1 of an excavator, for example, a jet boring indicated by reference numeral A, is provided with a vertical nozzle 2 vertically downward on a casing end surface 1a. And
The vertical nozzle 2 jets a high-pressure fluid jet J1 for excavating the soil G.

As a detailed example of the mounting position of the vertical nozzle 2, for example, the diameter is 139.8 mm (5.5i).
In (n), the high-pressure fluid jet J1 is attached (the vertical nozzle 2) so that the center of the high-pressure fluid jet J1 is located at a position closer to the center by a predetermined amount B from the outer periphery of the end surface (lower surface) 1a of the casing 1.
The value of the predetermined amount B is the clearance δ, as will be described later.
And the ejection angle θ of the nozzle 2.

The nozzle 2 for the high-pressure fluid jet J1 has a nozzle hole diameter of, for example, 3.5 mm, the injection pressure P0 at the nozzle hole position is, for example, 100 kg / cm ² , and the injection spread angle θ is vertical. It is 6.5 degrees to the line.
Strictly speaking, the spray spread angle θ is the soil G that can cut the soil G.
Is an angle forming a conical surface at a pressure equal to the uniaxial compressive strength σ = 1 kg / cm ^2, and is indicated by the line b in FIG.

Here, the high-pressure fluid jet J1 has a pressure damping characteristic as shown in FIG. 2 with respect to the jet distance (a vertically downward distance in the embodiment). FIG. 2 shows the injection distance on the horizontal axis and the pressure on the vertical axis on a logarithmic scale.
When the injection pressure P0 at the injection hole is 251 kg / cm ² , the excavation limit pressure (that is, uniaxial compressive strength) σ = 1 k
The attenuation distance up to g / cm2 is 32.7 cm (327
mm). Similarly, when the injection pressure P0 at the injection hole is 100 kg / cm ^{2 which} is the same as in the present embodiment, the distance at which the uniaxial compressive strength σ is reduced to σ = 1 kg / cm ² is 26.3 cm (263 mm).

Incidentally, FIG. 2 is based on "High-speed machine water" by Akio Yahiro
From the study on ground cutting and its application "
Pressure (Pm) on the central axis of water jet and distance from nozzle outlet
It is a graph which shows the relationship of separation (X). In Yahiro's experiment
P0 = 251kg / cm^TwoIs set as
Power P0 = 251kg / cm^TwoPressure drop on the injection axis at
It represents the characteristics of decline. The setting of this embodiment is P0 =
100 kg / cm ^Two For P, shown on the graph
0 = 251 kg / cm^TwoFrom the characteristic curve in the case of
I'm seeking by analogy.

The pressure distribution diagram in FIG. 3 shows the relationship between the increase in the distance from the injection center and the pressure attenuation in each horizontal cross section of the high-pressure fluid jet J1. As clearly shown in FIG. 3, the pressure of the jet J1 is attenuated in a normal distribution with respect to the distance from the jet center of the high-pressure fluid jet J1. In FIG. 3, the abscissa axis represents the lateral separation distance with respect to the injection center position indicated by the index 0 in the center, and the ordinate axis represents the ratio P of the pressure P at that distance to the injection center pressure Pm.
/ Pm is expressed as a dimensionless quantity.

According to the normal distribution graph of FIG. 3 and a conversion table (not shown), the pressure P at each point in this embodiment is P.
When the distance from the injection axis at which = 1 kg / cm ² is obtained,
In the present embodiment in which the spray spread angle θ of the nozzle used is 6.5 degrees, the maximum excavation width of soil is 14.75 mm. Therefore, as for the mounting position of the vertical nozzle 2 required for excavation while maintaining the set clearance “δ” of 10 mm, the nozzle center is 4.75 (= 14.75 from the casing outer circumference).
It is understood that the position of −10) mm is preferable.

In the case of the present embodiment in which the injection pressure is 100 kg / cm ² , the soil to be cut has a horizontal line with a substantially triangular shape and the center line VL of the high-pressure fluid jet from the vertical nozzle 2.
(Refer to FIG. 5) is a portion of a rotating body generated by rotating the rotating body as a rotating shaft.

That is, the high-pressure fluid jet J1 ejected from the vertical nozzle 2 does not eject from the nozzle 2 with the same outer diameter and the same cross-sectional area even if it is separated from the nozzle 2, but as it separates from the nozzle 2. The cross-sectional area increases slightly (has a jet divergence angle). On the other hand, the pressure of the jet J1 is separated and rapidly attenuated, and if the pressure of the jet becomes less than the uniaxial compressive strength of the soil to be excavated, the soil cannot be excavated.

Here, the pressure of the jet flow is highest on the injection center line LV, and becomes lower outward in the radial direction. As a result, the cross-sectional area of the high-pressure fluid jet J1 ejected from the nozzle 2 increases as the distance from the nozzle 2 increases, but when it reaches a certain distance or more from the nozzle 2, the cross-sectional area decreases as the distance increases. . In other words, the cross-sectional area of the high-pressure fluid jet J1 jetted from the nozzle 2 becomes maximum at the point of the certain distance.

Therefore, according to the present embodiment, the jet cross-sectional area at the above "constant distance", that is, the maximum cross-sectional area of the high-pressure fluid jet J1 is analyzed in advance as described above, and The arrangement of the nozzles 2 and the high-pressure fluid jet J1 can be adjusted so that the outer peripheral portion of the high-pressure fluid jet J1 in (1) reaches a position protruding outward from the casing 1 by a required clearance δ. As a result, it is possible to excavate the standing hole 3 while ensuring the required clearance δ.

FIG. 5 shows a second embodiment of the present invention. If an attempt is made to excavate the vertical hole using only the vertical nozzle 2 described above, there is a so-called uncut portion that cannot be excavated below the center of the lower end 1a of the casing. Therefore, in the second embodiment of FIG. 5, in addition to the vertical nozzle 2 shown in FIGS. 1 and 4, an inward nozzle 4 is provided at the lower end 1a of the casing,
The high pressure fluid jet J2 jetted from the inward nozzle 4 is configured to excavate the uncut portion of the vertical nozzle 2.

That is, the high-pressure fluid jet J2 jetted from the inward nozzle 4 crosses the extension line of the central axis CL of the casing 1 and collides with the high-pressure fluid jet J1 jetted from the vertical nozzle 2, and the inward nozzle At the collision position S between the high-pressure fluid jet J2 ejected from No. 4 and the high-pressure fluid jet J1 ejected from the vertical nozzle 2, the pressure of the high-pressure fluid jet J1 ejected from the vertical nozzle 2 is equal to the uniaxial compressive strength of the soil G. It is below the position T which has become.

According to the vertical hole excavation method and apparatus according to the second embodiment having such a configuration, the high-pressure fluid jet J1 jetted from the vertical nozzle 2 and the high-pressure fluid jet J2 jetted from the inward nozzle 4 are provided. Constitutes a so-called "cross jet". Therefore, the high pressure fluid jets J1, J
There will be no excavation vertically below or radially outside the two collision points S.

At the position T where the pressure of the high-pressure fluid jet J1 jetted from the vertical nozzle 2 becomes equal to the uniaxial compressive strength of the soil G, the cross-sectional area of the high-pressure fluid jet J1 jetted from the vertical nozzle 2 is maximum. It is nothing but the position that becomes. In a region vertically below that, the cross-sectional area of the high-pressure jet J1 is reduced. Therefore, according to the present embodiment configured so that the pressure of the high-pressure fluid jet J1 ejected from the vertical nozzle 2 collides below the position T at which the uniaxial compressive strength of the soil G becomes equal, The soil (G) radially outward of the maximum cross-sectional area of the jetted high-pressure fluid jet J1 is not excavated.

Further, according to the above-mentioned structure, the high pressure fluid jet J2 jetted from the inward nozzle 4 excavates the entire region corresponding to the projected area of the casing 1. Therefore, when the casing 1 is inserted, the vertical nozzle is inserted. The inconvenience that the 2 and the inward nozzle 4 contact with the soil G and are damaged is prevented.

6 and 7 show a third embodiment of the present invention. In FIG. 6, two pairs of nozzles 2-A, 4-A, 2-B and 4-B are provided on the end surface 1b of the casing 1. Of each pair of nozzles, nozzles 2-A, 2
-B is a nozzle that ejects in the vertical direction, and the nozzle 4-
A and 4-B are nozzles for injecting radially inward.

A high-pressure fluid jet J1-A is emitted from the nozzle 2-A.
Is jetted, and the high-pressure fluid jet J2-A is jetted from the nozzle 4-A, and the jets J1-A and J2-A are the collision points SA.
Form a cross jet that collides (or crosses). Similarly, the high-pressure fluid jet J1-B is ejected from the nozzle 2-B, and the high-pressure fluid jet J2-B is ejected from the nozzle 4-B. The jets J1-B and J2-B are at the collision point SB. It forms a colliding cross jet.

The arrangement of the nozzles 2A, 4A, 2B and 4B and the positions of the jets J1-A, J2-A, J1-B and J2-B are shown in FIG. The jets J1-A, J
Since 1-B is ejected (from the nozzles 2A and 2B) in a direction perpendicular to the paper surface of FIG. 7, it is not clearly shown in FIG.

In FIG. 6, for simplification, the jet J1-
The cross jet composed of A and J2-A will be described. The jets J1-A and J2-A lose most of their kinetic energy when they collide (cross) at the collision point SA. The jet flow existing after the collision is indicated by reference sign Je-A, but the energy held by the jet flow Je-A is relatively small.

Due to the jet flow Je-A, the ground to be excavated is additionally excavated by the distance JH in the horizontal direction from the collision point SA. As described above, since the energy held by the jet Je-A is relatively small, the horizontal excavation distance JH after the collision does not have a large numerical value. However, it is larger than the required clearance δ. That is, in the third embodiment of FIGS. 6 and 7, the necessary clearance δ is excavated by the energy remaining after the collision of the cross jets.

Jets J1-from nozzles 2-B and 4-B
The same applies to B and J2-B. However, the jet after the collision of the jets J1-B and J2-B is represented by the symbol J
e-B.

Here, the nozzles 2-A, 4-A, 2-B,
4-B is shown in FIG. 7 so that two pairs of intersecting jets do not interfere with each other.
It is arranged as shown in. As is clear from FIG.
The nozzles 2-A, 4-A, 2-B, and 4-B are arranged so that the jet flows J2-A and J2-B directed inward in the radial direction do not interfere with each other in the central portion of the excavation region. It has been done. However, the jet J2-
There is a region RA which is arranged so that A and J2-B do not interfere with each other and which is not excavated by the jets J2-A and J2-B in the central portion. The same is true even if the number of nozzles and the logarithm of the main cross flow are increased. However, the region RA does not adversely affect the excavation work because it collapses without being excavated by the jet flow.

In FIG. 6, cross jets J1-A and J2-
When the crossing angle θ of A is small, the crossing jet J1-A,
The energy held by J2-A does not disappear at the collision point SA, and a combined jet with the jets J1-A and J2-A is generated.
Here, the length by which the jet J2-A excavates the ground is the jet J1.
Since it is longer than −A, the energy attenuation before reaching the collision point SA is large. Therefore, the component of the combined jet Je-A toward the outer side in the radial direction is small, and the clearance δ does not become unnecessarily large even when the crossing angle θ is small.

If the clearance δ does not reach an appropriate value, the nozzles 4-A and 4-B may be adjusted to control the jet angle of the jet J2-A that is directed inward in the radial direction.

In the illustrated third embodiment, the jets J1, J2
, Two pairs (J1-A and J2-A, J2-A and J2-B) intersect, but one pair of jets J1 and J2 may intersect. And three or more pairs of jet streams may intersect. However, two or more pairs of intersecting jets intersect so that the horizontal force acting on the excavator is balanced, and the intersecting jets (paired jets) are arranged at equal intervals in the circumferential direction. Is preferred.

It should be noted that the illustrated embodiment and various numerical values such as the dimensions described therefor are merely examples and do not limit the technical scope of the present invention.

[0048]

The effects of the present invention are listed below. (1) By preliminarily analyzing the jet cross-sectional area at a fixed distance, the nozzle of the nozzle should be set so that the outer peripheral portion of the high-pressure fluid jet at the maximum cross-sectional area reaches the position where it is outwardly ejected by the required clearance from the casing. The arrangement and the high-pressure fluid jet can be adjusted, which makes it possible to excavate the vertical hole while ensuring the required clearance. (2) The high-pressure fluid jet ejected from the vertical nozzle and the high-pressure fluid jet ejected from the inward nozzle constitute a so-called “cross jet”, and therefore, is perpendicular to the collision point of the high-pressure fluid jet. It is not excavated downward in the direction or outward in the radial direction. (3) Since the high-pressure fluid jet ejected from the inward nozzle excavates the entire area corresponding to the projected area of the casing, the vertical nozzle and the inward nozzle come into contact with the soil and are damaged when the casing is inserted. Inconvenience is prevented.

[Brief description of drawings]

FIG. 1 is a vertical hole excavation cross-sectional view showing an injection state of a vertical nozzle according to a first embodiment of the present invention.

FIG. 2 is a graph showing the attenuation of pressure on the injection axis.

FIG. 3 is a normal distribution diagram showing a pressure distribution in each cross section.

FIG. 4 is a view showing a combination of excavable regions by vertical nozzles.

FIG. 5 is a sectional view showing a second embodiment of the present invention.

FIG. 6 is a vertical sectional view showing a third embodiment of the present invention.

7 is a sectional view taken along the line A7-A7 of FIG.

[Explanation of symbols]

1 ... Casing 2 ... Vertical nozzle 3 ... Vertical hole 4 ... Inward nozzle A ... Excavator B: predetermined amount G: soil J1, J2 ... High-pressure fluid jet δ: Clearance (clearance with the ground)

Claims (6)

[Claims] 1. In a vertical hole excavation method for excavating a vertical hole by a high-pressure jet injected from a vertical nozzle provided on an end face of a casing, the vertical nozzle ejects a high-pressure fluid jet in the vertical direction and is injected in the vertical direction. A vertical hole excavation method characterized by excavating the soil while expanding the high-pressure jet so that the required clearance can be secured. 2. In a vertical hole excavation method for excavating a vertical hole by a high pressure jet injected from a vertical nozzle and an inward nozzle provided on an end surface of a casing, the vertical nozzle ejects a high pressure fluid jet in a vertical direction. The high-pressure jet injected into the nozzle spreads the pressure so as to secure the required clearance and attenuates the pressure.The high-pressure fluid jet injected from the inward nozzle is jetted from the vertical nozzle across the extension of the central axis of the casing. The high-pressure fluid jet injected from the inward nozzle and the high-pressure fluid jet injected from the vertical nozzle collide with the high-pressure fluid jet, and the pressure of the high-pressure fluid jet injected from the vertical nozzle is one axis of the soil. A vertical hole excavation method characterized in that it is below the position where it becomes equal to the compressive strength. 3. In a vertical hole excavation method of excavating a vertical hole by a high pressure jet injected from a vertical nozzle and an inward nozzle provided on an end face of a casing, the vertical nozzle ejects a high pressure fluid jet in a vertical direction, The high-pressure fluid jet ejected from the directing nozzle crosses the extension line of the central axis of the casing and collides with the high-pressure fluid jet ejected from the vertical nozzle, and after the collision, the clearance required by the energy remaining in the high-pressure fluid jet is required. The vertical hole excavation method is characterized in that 4. A casing having a vertical nozzle provided on an end face thereof, the vertical nozzle being configured to eject a high-pressure fluid jet in the vertical direction, and arranged at a position where a necessary clearance can be secured. A vertical hole drilling device characterized by the above. 5. A casing having a vertical nozzle and an inward nozzle provided on an end surface thereof, the vertical nozzle being configured to eject a high-pressure fluid jet in a vertical direction, and arranged at a position where a necessary clearance can be secured. In the inward nozzle, the high-pressure fluid jet injected from the nozzle crosses the extension line of the central axis of the casing, and the pressure of the high-pressure fluid jet injected from the vertical nozzle is equal to the uniaxial compressive strength of soil. A vertical hole excavating device, which is arranged so as to collide below the vertical hole. 6. A vertical nozzle and an inward nozzle for ejecting a high-pressure jet are provided on an end surface of the casing, the vertical nozzle ejects a high-pressure fluid jet in a vertical direction, and the inward nozzle is
The high-pressure fluid jet injected from there crosses the extension of the central axis of the casing and collides with the high-pressure fluid jet injected from the vertical nozzle, and after the collision, the energy remaining in the high-pressure fluid jet provides the necessary clearance. A vertical hole excavation device, which is configured to be excavated.