JPS60203731A - Moving mechanism for nozzle in ground improving device - Google Patents

Abstract

PURPOSE:To cause a nozzle to be protruded in a horizontal direction in response to the pressure of excavating water, by a method wherein a hydraulic cylinder, which actuates a parallel movement mechanism for supporting the nozzle, is communicated with a circuit which feeds the excavating water to the nozzle. CONSTITUTION:A nozzle 1 is attached to the forward end of an excavation pipe 3 through a parallel movement mechanism 2, and a hydraulic cylinder 17 (5), which actuates the parallel movement mechanism 2, is communicated with an excavating water feed circuit 20. In formation of a cavity in earth, with the excavation pipe 3 rotated, ultra-high pressure water is fed through the circuit 20, and excavation is effected through injection of high-pressure water through the nozzle 1. When, with the progress of excavation, an excavating wall surface is moved backward, by increasing the feed pressure of the high-pressure water in the circuit 20 to higher than a given value, a ram 17a is raised against elasticity of a spring 21. This causes the nozzle 1 to be protruded in the direction of the excavating wall surface in a condition to be kept in a horizontal direction to shorten a distance to the wall surface, resulting in the possibility to improve excavation capacity.

Description

DETAILED DESCRIPTION OF THE INVENTION (n) Technical distribution of the invention In the present invention, a pilot hole is drilled underground. Later, high-pressure water is injected horizontally to form a cylindrical cavity in the ground, and ground improvement materials such as concrete and REET are installed in the cavity to form a new ground. The present invention relates to a nozzle movement mechanism in a ground modification device suitable for application to modification methods, etc.

(b), Background of the technology When constructing an artificial ground, a cavity is excavated underground and the hollow part is replaced with ground improvement material such as concrete, resulting in a plate-shaped solid artificial ground underground. A construction method has been proposed for constructing the
, JP-A-58-24020, JP-A-58-2=, -61
15, Japanese Unexamined Patent Publication No. 58-120819, etc.).

In this construction method, the ground is excavated by injecting ultra-high pressure water from a nozzle.
As the distance from the nozzle to the wall of the cavity to be excavated increases as excavation progresses, the excavation ability of ultra-high pressure water decreases.

(C), Prior art and problems Figure 3 shows the latest proposal for the nozzle movement mechanism. It is a figure showing an example.

Therefore, in order to solve these problems, recently, as shown in FIG. By making the nozzle 1 movable in the horizontal direction in the figure, and by bringing the nozzle 1 close to the wall of the cavity being excavated, even if the pressure of the excavated water ejected from the nozzle 1 is low, it can be used in large-diameter cavities. Proposals have been made to make drilling possible.

However, in such a case, it is necessary to supply pressure oil for driving the hydraulic cylinder 5 that drives the parallel motion mechanism 2, and the pressure oil hose 6 is connected to the excavation pipe 3 along the excavation pipe 3.
It will be installed in a fixed manner. However, since the excavation pipe 3 normally performs a rotational movement during excavation, in order to supply pressure oil from the outside to the pressure oil hose 6 which is in a rotating state together with the excavation pipe 3, a complicated joint such as a swivel joint 1 is required. It is necessary to supply pressure oil through the ground modification device 13, which has the disadvantage of complicating the structure of the ground modification device 13.

Furthermore, a hydraulic pump or the like is required to send pressure oil to the hydraulic cylinder 5, which inconveniently increases the size of the incidental equipment.

(d) 6 Purpose of the Invention In order to eliminate the above-mentioned drawbacks, the present invention eliminates the need for a pressure oil port for driving the parallel motion mechanism, and therefore eliminates the need for complicated joints such as swivel joints and special accessories such as hydraulic pumps. The purpose of the present invention is to provide a nozzle movement mechanism that can provide a ground modification device with a simple structure that does not require any equipment.

(e) Configuration of the 0 invention, that is, the present invention provides a nozzle in an excavation pipe so that it can freely protrude and move in the horizontal direction through a parallel movement of 4 m, and a hydraulic drive that drives the parallel movement mechanism in a parallel interlocking mechanism. The hydraulic driving means is further connected to an excavation water supply circuit to the nozzle.

(Margin below) (f) 0 Examples of the invention Examples of the present invention will be described below based on the drawings. will be explained in detail.

FIG. 1 is a front view showing an example of a ground modification device to which an embodiment of the nozzle moving mechanism according to the present invention is applied, and FIG. 2 is a fluid circuit diagram of the nozzle moving mechanism in FIG. 1.

As shown in FIG. 1, the ground modification device 13 has a tower-shaped support means 12 erected on the ground surface 9, and a drive device 11 for the excavation pipe 3 is installed on the support means 12. ing.

A drilling pipe 1-' is provided in the driving device 11 so as to be rotatably driven by the driving device 11, and a bit 15 is provided at the lower end of the basic pipe 3 in the figure. Above the bit 15, a parallel movement mechanism 2 such as a pantograph mechanism, which constitutes the nozzle movement mechanism 16 according to the present invention, is provided.
Parallel M! The l1IJ mechanism 2 is provided with a hydraulic cylinder 17, which is a hydraulic drive means, in the form of a ram 17a which is provided so as to be freely protrusive and driveable in the vertical direction, and whose tip is pivoted to a part of the link constituting the mechanism 2. There is. The parallel motion mechanism 2 has
A nozzle 1 is provided so as to be able to protrude and move from side to side in the drawing, that is, in the horizontal direction, by means of the parallel movement mechanism 2.

As shown in FIG. 2, the nozzle l and the hydraulic cylinder 17 are an excavation water supply installed in a manner fixed to the excavation pipe 3 in parallel to the axial direction of the excavation pipe 3, that is, in the vertical direction in FIG. The hydraulic cylinder 17 has the above-mentioned ram 17. A is provided with Cζ that is movable in the vertical direction in the figure. A spring 21 is contracted above the ram 17a, and the spring 21 always urges the ram 17a in the direction of the arrow, that is, downward.

Note that a stand pipe 8 is attached to the ground at the upper end of the pilot hole 4 drilled by the drilling pipe 3.
30 and is installed so as to cover the circumference of the excavation pipe 3.

Since the ground modification device 13 has the above configuration, when the ground modification device 13 excavates a hole for constructing an artificial ground etc. in the ground 30, the drive device 11 rotates the trench hIl pipe 3. Then, use the bit 15 to drill the pilot hole 4 downward in FIG. When drilling with bit 15, the depth of pilot hole 4 is D.
However, during excavation with the bit 15, no water is supplied to the ultra-high pressure I layer agent water supply circuit 20, so the ram 1' of the hydraulic cylinder 17
The piston 7a maintains its protruding state in the input direction by pressing the piston 17b in the direction A in FIG. 2 by the pressure of the spring 21. Therefore, parallel chain rJJJ mechanism 2
excavation is carried out with the nozzle 1 maintained in its folded state on the side of the cutting pipe 3 and the nozzle 1 also held in the retracted position on the side of the drilling pipe 3. In this state, since the distance [Ll] from the tip of the nozzle 1 to the axis of the drilling pipe 3 is smaller than the radius of the pilot hole 4, the pilot hole 4 formed by the bit 15 and the drilling pipe 3 is
The drilling is performed smoothly without the nozzle 1 coming into contact with the wall surface of the pilot hole 4 in the I principle.

When the drilling bit 15 reaches the depth DP, the drilling pipe 3 is rotated and ultra-high pressure water 18 is injected from the nozzle 1 into the surrounding ground 30 to form a cylindrical cavity 22 around the pilot hole 4. However, the excavated soil generated during excavation is discharged from the lower part of the excavation pipe 3 to the outside through the inside of the excavation pipe 3 in the form of a slurry together with the muddy water 25 filled inside the pilot hole 4.

The ultra-high pressure water 18 is ejected from the nozzle 1 by supplying ultra-high pressure water to the nozzle 1 via an ultra-high pressure drilling water supply circuit 20. 17, the ultra-high pressure water 18 in the ultra-high pressure excavation water supply circuit 20 is supplied to the nozzle 1 and also to the hydraulic cylinder 17 at the same time. If the pressure of the ultra-high pressure water 18 supplied to the hydraulic cylinder 17 is below a predetermined pressure value P, the piston 17b cannot be moved in the direction B against the elasticity of the spring 21.
Therefore, the nozzle 1 continues the excavating operation while remaining in the retracted state. However, as the excavation progresses, a cylindrical cavity 22 is formed around the pilot hole 4, and the distance between the nozzle 1 and the cavity wall surface 2211 being excavated becomes longer, reducing the excavation ability of the nozzle 1. The supply pressure of the ultra-high pressure water 18 via the excavation water supply circuit 20 is increased to a predetermined value P or higher. Then,
While the jetting pressure of the ultra-high pressure water pipe 8 from the nozzle 1 increases and the cutting ability of the spring 2 increases accordingly,
The ram 17a was in a protruding state in the direction A due to the elasticity of the ram 17a.
is caused by the ultra-high pressure water 18 exceeding the pressure P.
direction B along with the piston 17b in a manner that resists the elasticity of
That is, it moves upward and changes the parallel transport rAJ mechanism 2 from its folded state to its extended state as shown by the imaginary line in FIG. As a result, the distance between the tip of the nozzle 1 and the 3rd axis of the excavation pipe reaches L2 in the G direction, that is, in the direction of the wall surface 22'a during excavation, while the discharge port 1a of the nozzle 1 maintains the horizontal direction. move protrudingly. Then, the distance X between the nozzle 1 and the cavity wall surface 22a, which is the surface to be excavated, is significantly shortened compared to the previously stored state of the nozzle 1, and the cutting capacity of the ultra-high pressure water 18 from the nozzle 1 is increased. is significantly improved, and cavities 22 with large diameters can be preformed smoothly and reliably.

When the cavity 22 of a predetermined size is formed, the ultra-high pressure water 1 from the ultra-high pressure excavation water supply circuit 20 is
When the supply of the nozzle 1-\ of No. 8 is stopped, the jetting of the ultra-high pressure water 18 from the nozzle 1 is stopped, and the excavation work is completed.

Note that when the supply of the ultra-high pressure water 18 from the ultra-high pressure excavation water supply circuit 20 is stopped, the ram 17a is moved to protrude in the A direction by the spring 21, and the parallel motion mechanism 2, which had been in the protruding state, is moved to the nozzle 1. At the same time, the storage state is returned to the stored state shown by the solid line in FIG.

Next, while rotating the excavation pipe 3 and pulling up the nozzle 1 from the lower part of the cavity 22 in the direction B, the ground improvement material is injected at high pressure from the nozzle 1 into the cavity 22 via the excavation water supply circuit 20. The inside of the cavity 22 is not filled with soil improvement material (in addition, the f! cut pipe 3 is used as a tremie pipe,
The cavity 22 and the pilot hole I/hole 4 may be filled with a ground improvement material such as concrete. ). At this time, the improving material can be efficiently and reliably filled into the cavity 22 by moving the nozzle 1 appropriately in the direction G1 and ejecting the improving material.

In this way, when the excavation pipe 3 is pulled up in the direction B while filling the ground improvement material into the cavity 22 and the pilot hole 4, the filled improvement material solidifies and the soil 30
A strong man-made foundation will be built inside.

- Once the artificial ground has been constructed by JR, a pilot hole 4 is newly drilled at a position adjacent to the constructed artificial ground to construct a cavity 22, and the cavity 22 is further filled with soil improvement material. and the previously constructed cavity 22 (which has already been filled and solidified with the ground improvement material) are connected in the horizontal direction to expand the artificial ground.

In this embodiment, the spring constant of the spring 21 of the hydraulic cylinder 17 is set to a predetermined pressure value P.
With the above, the ram 17 immediately moves in the direction B against the spring 21.
Therefore, the nozzle 1 is in a retracted state in which the parallel movement mechanism 2 is folded, and in an extended state (in which it is fully protruded in the G direction). For example, the spring constant of the spring 21 can be set larger than that of this embodiment, and as the pressure of the ultra-high pressure water 18 supplied from the ultra-high pressure excavation water supply circuit 20 increases and decreases, It is also possible to configure the nozzle 1 on the parallel movement mechanism 2 to move forward and backward in the direction A or B in a manner corresponding to the pressure value. The nozzle position is moved in the G111 direction according to the pressure of the ultra-high pressure water 18, allowing finer control of the nozzle position.

(g) 0 Effects of the Invention As explained above, according to the present invention, a hydraulic drive means such as a hydraulic cylinder 17 is provided as a drive means for the parallel movement mechanism 2 of the nozzle 1, and the hydraulic drive means is provided with a hydraulic drive means for the nozzle 1. Since the excavation water supply circuit such as the connected ultra-high pressure excavation water supply circuit 20 is connected, special pressure oil hoses, hydraulic pumps, etc. are required as in the case where a hydraulic 151 g driving means is provided as the drive means of the parallel motion mechanism 2. It is no longer necessary to provide a water supply circuit in addition to the conventional excavation water supply circuit, and the accompanying swivel joint 1- etc. are also no longer required.
It becomes possible to simplify the entire structure.

In addition, near the connection part with the nozzle 1 of the excavation water supply circuit connected to the nozzle 1 and the hydraulic drive means (to the extent that movement of the nozzle 1 in the G and ■■ force directions is allowed,
Needless to say, a certain amount of extra length and flexibility is required, and therefore, it is desirable that the connection portion with the nozzle 1 be constructed of a rubber bow or the like with some degree of flexibility.

[Brief explanation of drawings]

FIG. 1 is a front view showing an example of a ground modification device to which an embodiment of the nozzle moving mechanism according to the present invention is applied, FIG. 2 is a fluid circuit diagram of the nozzle moving mechanism in FIG. 1, and FIG. FIG. 3 is a diagram showing a recently proposed example of moving nozzle sliding. 1 - Nozzle 2 Parallel movement mechanism 3 - Principle pipe 4 - Pilot hole 13 - Ground modification device 15 - Bit 16 - Movement mechanism 17 Water pressure drive means (hydraulic cylinder) 18 - Drilling water (ultra high pressure water) 20- Drilling water supply circuit (ultra-high pressure drilling water supply circuit) 30...Ground applicant Mitsui Construction Co., Ltd. N.I.T. Co., Ltd. Agent Patent attorney ['lJ Moeji Figure 1 Dangen 25] Figure 2 G Procedural amendment (method) May 14, 1980 1 Indication of the case 1988 Patent Application No. 19026 2 Name of the invention Nozzle moving mechanism classified as a ground modification device 3 Person making the amendment Relationship with the case Patent application Address 3-10-1 Iwamoto-cho, Chiyoda-ku, Tokyo Name (Name) Mitsui Construction Co., Ltd. Representative Ryoji Machida Address 1752 Zushi-cho, Machida-shi, Tokyo Name (Name)
Nissan Freeze Co., Ltd. Representative Motohiro Goto 6 Full text of the specification to be amended 7 Engraving of the specification of the amendment (no changes to the content)

Claims (1)

[Scope of Claims] The ta! has a rotatable drilling pipe with a bit attached to its tip, and the ta! A nozzle is provided at the tip of the excavation pipe, and a water supply circuit is installed in the excavation pipe in a manner connected to the nozzle, and high-pressure excavation water is supplied to the nozzle via the excavation water supply circuit, Therefore, before i
In a ground modification device that excavates the ground around a pilot hole by ejecting high pressure water from its own nozzle, n nozzles are attached to the excavation pipe and can be moved horizontally to protrude through a parallel movement mechanism. and the parallel transport fil
A nozzle moving mechanism in a ground remodeling device, wherein a J mechanism is provided with a hydraulic drive means for driving the parallel movement mechanism, and the hydraulic drive means and the excavation water supply circuit are connected.