JPH08302672A - Method and device for jet grout construction - Google Patents

Abstract

PURPOSE: To build a segment-form consolidated body having any angle of opening using one high speed nozzle. CONSTITUTION: A threefold pipe structure equipped with a monitor 4 is inserted in a casing 1 which is set in a guide hole H and is drawn up along with the casing 1 while the pipe structure is rotated, and a high speed jet is spouted from a high pressure nozzle 5 furnished on the monitor 4 through the opening 2 in the casing 1 so that the natural ground G is cut into a segment shape. To the void 12 a consolidating material 11 self-standing is spouted from a low pressure nozzle so that the void is filled therewith.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jet grout method, and more particularly to a jet grout method for forming a fan-shaped solid body and an apparatus for carrying out the method.

[0002]

2. Description of the Related Art In a conventional jet grout method, as shown in FIG. 6, a triple tube 3 having a monitor 4A is inserted into a guide hole H, and the triple tube 3 is rotated and pulled up while the high pressure nozzle 5 of the monitor 4A is being pulled up. A high-speed jet 10 in which water is surrounded by air is jetted from the water, and the solid material 11A is jet-filled from the low-pressure nozzle 6A of the monitor 4A into the void where the natural ground G is cut by the jet 10 to form a columnar solid Building C.

On the other hand, as shown in FIG. 7, when a plurality of columnar solidified bodies C are erected in a predetermined range W in an aligned manner to improve the ground, a semicircular (or fan-shaped) portion C1 shown by diagonal lines is formed. Construction is wasted. Therefore, as indicated by reference numeral C2, a solid body having a fan-shaped horizontal cross section (that is, a fan-shaped portion C
It is desirable to build only 2 solids.

Further, as shown in FIG. 10, when a plurality of columnar solidified bodies C are built in an array to build a wall-shaped underground solidified body, a fan-shaped solidified body as indicated by reference numeral C11. By constructing, the water-stopping property of the wall-shaped underground solid body is further improved.

In response to such a request for constructing a columnar solidified body, conventionally, as shown in FIGS. 8 and 9, two high pressure nozzles 5, 5 are provided radially on the monitor 4B at an opening angle α, for example.
A fan-shaped solid C3 having an opening angle α shown by a chain line was formed.

[0006]

However, in the above-mentioned prior art, as shown in FIG. 9 in the case of solid ground,
There is a problem that only the natural ground G near the high-speed jets 10 and 10 is cut, and the predetermined fan-shaped solid C3 cannot be obtained. Although it is possible to deal with this problem by providing a plurality of high-pressure nozzles 5, the structure of the monitor becomes extremely complicated and the cost rises, which is practically impossible.

Further, in the monitor 4B shown in FIGS. 8 and 9, since the opening angle α of the two high pressure nozzles 5 and 5 is fixed, the solid body of the semicircular fan-shaped portion C2 shown in FIG. In order to build (opening angle 180 °), it is necessary to manufacture a dedicated monitor.

Further, the opening angle of the fan-shaped solidified bodies C11 shown in FIG. 10 is set by the interval between the columnar solidified bodies, but the interval differs depending on the construction site. However, in the prior art, since the opening angle α of the high pressure nozzles 5 and 5 is fixed, it is not possible to build a fan-shaped solid body suitable for each site.

The present invention has been proposed in view of the above-mentioned problems of the prior art, and provides a jet grout method and apparatus capable of constructing a fan-shaped solid body having an arbitrary opening angle with a single high pressure nozzle. It is intended to be provided.

[0010]

According to the jet grout method of the present invention, a guide hole boring step for boring a vertical guide hole, and a casing having an opening with a constant circumferential dimension in a part of the lower portion are used as the guide. A casing inserting step of inserting into the hole, a triple tube inserting step of inserting a triple tube equipped with a monitor into the casing, a pull-up while rotating the monitor and the triple tube, and a pull-up without rotating the casing of the monitor. While injecting a high-speed jet from the high-pressure nozzle to cut the ground into a fan shape through the opening of the casing, the low-pressure nozzle of the monitor injects a solidifying material to mix the cut ground and the solidifying material. And a solidified body constructing step of constructing a solidified body having a fan-shaped horizontal cross section.

Here, the term "vertical" does not mean only a completely vertical direction, but also includes a range of an inclination angle of ± 45 ° with respect to a vertical line, that is, a range inclined to the vertical direction. Used in.

In other words, the consolidating body having a fan-shaped cross section constructed according to the present invention can be constructed by inclining it with respect to the vertical direction, and its longitudinal center axis is relative to the vertical line. The tilt angle may be in the range of ± 45 °.

Accordingly, the phrase "horizontal direction section" means a section in a direction perpendicular to the guide hole excavating direction or a direction perpendicular to the longitudinal direction of the solid body.

The apparatus of the present invention for carrying out the above-described jet grout method has a casing to be inserted into the guide hole, and an opening having a constant circumferential dimension is formed in a part of the lower portion of the casing. A triple tube for insertion into the casing, a monitor is provided on the triple tube, and a high-pressure nozzle for high-speed jet injection and a low-pressure nozzle for solidifying material injection are provided on the monitor. It has a pulling means for pulling the pipe while rotating and for pulling the casing without rotating.

In carrying out the present invention, as the pulling means, known commercial products can be applied.

[0016]

In the jet grouting method and apparatus of the present invention constructed as described above, the high-speed jet and the jet of the consolidating material jetted from the rotating monitor are jetted over the entire circumference of 360 °, but the casing is used for the grounding. Invasion into the mountains is blocked. However, since an opening having a constant circumferential dimension is formed in a part of the lower portion of the casing, the high-speed jet toward the opening excavates the natural ground. In other words, the high-speed jet ejected from the opening excavates all the ground area (fan shape) radially outward of the opening, so that the horizontal direction of the excavated area (in the longitudinal central axis of the solidified body is The direction) is fan-shaped. As a result, only the straight portion is not excavated as in the prior art. Also,
The solidifying material jet flow toward the opening is mixed with the earth and sand in the portion excavated in a fan shape.

In this state, if the monitor and the triple pipe are pulled up while rotating and the casing is pulled up without rotating, the circumferential position of the casing opening does not change.
The cross-sectional shape of the built solid body in the horizontal direction (direction orthogonal to the central axis in the longitudinal direction of the solid body) becomes a uniform fan shape.

Since the fan-shaped opening angle is determined by the circumferential size of the opening of the casing, if a suitable opening is formed for each site, the fan-shaped opening having the optimum opening angle for each construction site is formed. You can build a union.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an apparatus embodying the present invention. This device fixes a casing 1 inserted in a guide hole H, a triple pipe 3 inserted in the casing 1 and provided with a monitor 4 at the bottom, a casing 1, and a triple pipe 3 via a swivel (not shown). The rotating device 7, a casing 1, the triple pipe 3, and a crane 8 that suspends the rotating device 7 are roughly configured. Reference numeral 9 in the drawing is a known hose for supplying the monitor 4 with high-pressure water, compressed air, and a solidifying material made of a self-supporting material. As the rotating device and the swivel, known and commercially available hoses are used. .

2 and 3, an opening 2 is formed in the casing 1 at a position facing nozzles 5 and 6 described later. Here, the opening angle α of the opening 2 is not limited to the example of FIG. 2, and the casing 1 in which the opening 2 having the optimum opening angle is formed according to the construction situation of each work site may be used. Of. That is, the cost of replacing the casing 2 with the one having the opening 2 having the desired opening angle α is much smaller than the cost of changing the arrangement and the number of nozzles.

In FIG. 4, the monitor 4 provided at the bottom of the casing 3 is of a known technique, and has a high pressure nozzle 5 at the top and a low pressure nozzle 6 at the tip. The high-pressure nozzle 5 injects a high-speed jet 10 in such a manner that a high-pressure water jet from the center is wrapped with an air jet. Then, the low-pressure nozzle 6 injects a (jet or) jet 11 of solidifying material (a jet ejected in a direction perpendicular to the paper surface in FIG. 4).

Here, there is no limitation condition for the solidifying material. Then, a solidifying material such as cement milk may be used, or a self-supporting material, that is, a material having a small fluidity and a small so-called "slump", such as mortar or concrete slurry (particularly concrete), may be used as a solidifying material. May be injected as.

Next, the mode of construction will be described.

(1) Guide hole drilling process The guide hole H is drilled by a boring machine (not shown). Here, the drilling direction of the guide hole includes not only a completely vertical direction but also a range in which the tilt angle with respect to the vertical line is ± 45 °, that is, a range tilted with respect to the vertical direction.

(2) Casing insertion step The casing 1 is hung by the crane 8 and inserted into the guide hole H.

(3) Triple Pipe Inserting Step The triple pipe 3 is hung and inserted into the casing 1 by the crane 8.

(4) Fan-shaped solid body construction step While rotating the triple pipe 3 by the rotating device 7 and pulling it up with the fixed casing 1 by the crane 8, the high-speed nozzle 10 jets a high-speed jet 10 and a low-pressure nozzle. The solidifying material 11 is sprayed from 6. Then, as shown in FIG. 2, the high-speed jet 10 is not jetted to the natural ground G by being blocked by the inner wall of the casing 1 in the portion of the casing 1 where there is no opening. Is jetted at the strength of. Therefore, in the illustrated example, about 1
The ground G in the range of 20 degrees is preferably cut into a fan shape. Then, the space 12 that is cut and defined is filled with the solidifying material 11 to build the fan-shaped solid body 13.

Here, in the illustrated embodiment, if the above-mentioned self-supporting material, for example, mortar, concrete slurry (particularly concrete), etc. is jetted and used as the solidifying material, it is cut by the high pressure jet 10 to form an image. Before the wall surface of the formed void 12 collapses, the solidified material 11 is filled so as to be piled up from below, and the unfilled portion is eliminated to prevent the wall surface of the void 12 from collapsing. Can improve the quality of. When a self-supporting material is used as the solidifying material 11, the solidifying material 11 is prevented from being drawn to the surface side from the guide hole H by being pulled by the air of the high-speed jet 10, and the waste of the solidifying material 11 is prevented. Solidifying material 11
The usage of is saved.

As shown in FIG. 5 by constructing the fan-shaped solidified bodies 13 as described above, when constructing the column-shaped solidified bodies C in the range W in an aligned manner, the fan-shaped solidified bodies are respectively arranged at both ends of the middle row. 1
3 (a semicircular fan shape with an opening angle α of 180 degrees in FIG. 5)
Can be built, and the conventional useless fan-shaped portion C1 shown in FIG. 7 can be eliminated. As described above, this opening angle α
Is to be determined by the interval between the columnar consolidated bodies C ....

[0031]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, it is possible to reduce the construction cost by constructing a fan-shaped solid body having an arbitrary opening angle with one high pressure nozzle.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a rock mass showing an apparatus for carrying out the present invention.

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

FIG. 3 is a side view showing a main part of the casing of FIG.

FIG. 4 is a side view showing a part of the monitor of FIG. 1 in section.

FIG. 5 is a plan view showing a construction example of the present invention.

FIG. 6 is a vertical cross-sectional view of a natural ground showing an example of a conventional construction mode.

FIG. 7 is a plan view illustrating a defect of a conventional construction example.

FIG. 8 is a vertical cross-sectional view of a natural ground showing another example of a conventional construction mode.

9 is a sectional view taken along the line BB of FIG.

FIG. 10 is a vertical cross-sectional view of a rock mass showing a construction mode of a fan-shaped solid body.

[Explanation of symbols]

 C, C10 ... Columnar solid C1, C2, C11 ... Fan-shaped portion C3 ... Fan-shaped solid G ... Ground H ... Guide hole α ... Opening angle 1 ... Casing 2 ... Opening 3 ... Triple tube 4, 4A, 4B ... Monitor 5 ... High-pressure nozzle 6, 6A ... Low-pressure nozzle 10 ... High-speed jet 11, 11A ... Caking material 12 ... void 13 and 14 ... fan-shaped solid body

Claims (2)

[Claims] 1. A guide hole drilling step for drilling a vertical guide hole, a casing inserting step for inserting a casing having an opening having a constant circumferential dimension in a lower part thereof into the guide hole, and a monitor. A triple pipe insertion step of inserting the provided triple pipe into the casing, and pulling up while rotating the monitor and the triple pipe, pulling up without rotating the casing, and jetting a high-speed jet from a high pressure nozzle of the monitor to the casing. While cutting the ground into a fan shape through the opening of the monitor, the solidified material is sprayed from the low-pressure nozzle of the monitor to mix the cut ground and the solidified material to build a solidified body having a fan-shaped horizontal section. A jet grout method characterized by including a solidified body building step. 2. The apparatus for carrying out the jet grout method according to claim 1, further comprising a casing to be inserted into the guide hole, and an opening having a constant circumferential dimension at a part of a lower portion of the casing. Formed, and has a triple tube for insertion into the casing, the triple tube is provided with a monitor, the monitor is provided with a high-pressure nozzle for high-speed jet injection and a low-pressure nozzle for injection of a solidifying material, and the monitor and An apparatus for carrying out a jet grout method, comprising a pulling means for pulling while rotating the triple pipe and pulling without rotating the casing.