JPS648159B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a propulsion method used in burying water and sewage and telephone cables, etc., and particularly to a propulsion method that can be effectively used in soft ground.

[Conventional technology and its problems]

In general, it is very difficult to apply the propulsion method in the above-mentioned soft soil, and it is necessary to use it in combination with auxiliary methods such as (a) pneumatic method, (b) chemical injection process, and (c) well point method, or by adjusting the pipe diameter. In some cases (800 mm), a knife edge with a shelf is used to stabilize the face ground. However, the combined use of such auxiliary methods requires a great deal of time and expense, and even in the case of a blade with a shelf, it has not been possible to completely prevent the collapse of earth and sand. Furthermore, the autonomy of the ground was not necessarily perfect with the above methods, and workers were constantly placed in dangerous conditions.

Therefore, in the past, for example,
A shield machine for shield construction method suitable for excavating soft silt layers and soft clay layers is known from Publication No. 13329.

Furthermore, a jet jet type shield excavator is known from Japanese Patent Application Laid-Open No. 53-16434, which loosens the ground with a jet jet and discharges it to the outside of the machine while maintaining the pressure.

However, the former type of shield machine simply presses the hood against the soft ground to squeeze out the earth and sand, so it cannot be applied at all when the ground has a certain hardness.

On the other hand, in the latter case, since a jet jet is provided, even if the ground is somewhat hard, the earth and sand can be discharged by loosening it. However, in this shield machine, the jet jet is ejected from the entire opposing inner wall, so it is necessary to loosen not only the entire face, that is, the entire surface of the hood, but also the area around it. The weight of the excavation pipe pushes it downward, making it difficult to move the excavation pipe straight.

The present invention aims to solve the above-mentioned problems, and its purpose is to provide a propulsion method that allows propulsion work to be carried out quickly and accurately on soft ground while sufficiently ensuring the straightness of the propulsion pipe. There is a particular thing.

[Means for solving problems]

Hereinafter, means for solving the above problems will be specifically explained based on the embodiments shown in the attached drawings.

1 to 3 show preferred embodiments of the propulsion device (propulsion tip) used in the propulsion method according to the present invention, in which 1 is the tip of the propulsion tube, 2 is the face jack 3 This is a cutting edge that is inserted into the tip of the furthest propulsion tube 1 in a state where the direction can be adjusted through the blade.

The cutting edge 2 essentially consists of a short cylindrical portion 4, a funnel-shaped consolidation surface forming portion 5 attached from the tip of the short cylindrical portion 4 toward the inner rear, and a reduced diameter end 5a of the consolidation surface forming portion.
It is composed of a reduced diameter pipe 6 for earth and sand discharge that is connected to the pipe.

In the above configuration, the reduced diameter pipe 6 for earth and sand discharge is preferably connected to the reduced diameter end 5a by a flange connection,
Furthermore, the length can be appropriately selected in response to changes in the N value (number of penetrations) of earth and sand, consolidation force, etc., and safety can be improved.

Furthermore, the flange connection is used in order to enable removal of large stones or boulders by removing the reduced diameter pipe 6 for discharging the earth and sand, such as when large stones or boulders are mixed in the earth and sand. In this case, inject chemicals into the consolidated ground A to ensure self-support.

Furthermore, the reduced diameter pipe 6 for earth and sand discharge has a blocking plate 1 at the rear end.
0 is installed, and the reduced diameter pipe 6 for earth and sand discharge is completely occluded during work stoppages, etc., to ensure the safety of workers.

Further, the cutting edge angle α of the cutting edge 2 shall be changed depending on the soil quality.

Moreover, 7 is a pressing device for pressing the propulsion tube 1 and bringing about a consolidation effect.

Furthermore, 8 penetrates the reduced diameter pipe 6 for earth and sand discharge in a loosely fitted state, and its tip is connected to the central part 12 of the consolidated ground 11.
This is the introduction pipe extended to the

Next, the procedure of the propulsion method of the present invention using the propulsion device having the above configuration will be specifically explained with reference to FIGS. 4 to 7.

First, as shown in Fig. 4, the reduced diameter pipe 6 for earth and sand discharge
The entire propulsion tube 1 is pressed by the pressing device 7 with the entire propulsion tube 1 closed with the closing plate 10 under the condition (T+l・t<P) (where, T: total pressure of the pressurizing surface, l: pipe length of the penetration part,
t: frictional resistance per unit length of the pipe outer periphery, P: driving force), thereby causing the central consolidation area 12 of the consolidation ground 11 and the annular consolidation area 13 around the central consolidation area 12 to The earth pressure T increases with the passage of propulsion time, causing a consolidation dehydration phenomenon.

Thereafter, as shown in FIG. 5, the closing plate 10 is opened and the water guide pipe 8 is extended to the central consolidation area 12 of the consolidation ground 11.

Then, pressurized water is injected into the central consolidation part 12 of the consolidation ground 11 through the water guide pipe 8. Note that the position of the spouting end of the water guide pipe 8 can be controlled depending on the soil properties.

By such injection, the consolidation force of the central consolidation section 12 is first weakened, and the earth and sand in the central consolidation section 12 flows out into the foremost propulsion tube 1 through the reduced diameter tube 6 for earth and sand discharge.

Next, as the consolidation force of the central consolidation area 12 weakens, the consolidation of the annular consolidation area 13 around the central consolidation area also weakens uniformly over the entire circumference, and the earth and sand are transferred to the central consolidation area 11.
, and then flows out into the foremost propulsion pipe 1 through the reduced diameter pipe 6 for earth and sand discharge.

Thereafter, the spilled sand is removed by the required evacuation means (e.g.
(belt conveyor) to the outside of the propulsion tube 1.

Next, as shown in FIG. 6, the reduced diameter pipe 6 for earth and sand discharge is closed with a closing plate 10, the direction of propulsion is corrected using the face jack 3 as shown in FIG. 7, and the above steps are repeated. This will allow the promotion work to continue.

〔Effect of the invention〕

As described above, the present invention has the following effects.

(b) By weakening the consolidation force in the central consolidation area after consolidation, it is possible to uniformly weaken the consolidation force in the surrounding annular consolidation area, allowing the earth and sand to flow out effectively, and making it possible to move the propulsion pipe in a curved manner. You can go straight straight without having to worry about it.

(b) A small-diameter water guide pipe is loosely fitted through the reduced-diameter pipe for earth and sand discharge to the central consolidation area, and faces the central consolidation area.
Since pressurized water can then be injected, the injection position of the pressurized water can be adjusted to suit the properties of the soil.

(c) Since the propulsion tip portion is removably connected to the reduced diameter pipe for discharging dirt, it is possible to prevent boulders, etc. from clogging the reduced diameter pipe for discharging dirt.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the construction state of the propulsion device used in the propulsion method according to the present invention, Fig. 2 is a sectional front view of the same device, Fig. 3 is a sectional view taken along the line of Fig. 2, and Fig. 4 FIG. 7 is an explanatory diagram of the propulsion process. In the figure, 1: Propulsion pipe, 2: Blade mouth, 3: Face jack, 4: Short cylindrical part, 5: Funnel-shaped consolidation surface forming part, 5a: Reduced diameter end, 6: Reduced diameter pipe for earth and sand discharge, 7:
Pressing device, 8: Water guide pipe, 10: Closure plate, 1
1: Consolidated ground, 12: Central consolidation area, 13: Annular consolidation area.

Claims (1)

[Claims] 1 The propulsion tip, which has a funnel-shaped consolidation surface formed on the front and a reduced-diameter pipe for earth and sand discharge removably connected to the rear, is pressed into soft ground, the ground near the pressure-welded area is consolidated, and a small-diameter water guide pipe is created. A reduced diameter pipe for earth and sand discharge is loosely inserted into the central consolidated area of the consolidated ground, and pressurized water is injected from the tip of the water guide pipe into the central consolidated area. The consolidation force of the central consolidation area is weakened and the earth and sand in the same area is discharged to the rear through the reduced diameter pipe for earth and sand discharge, and at the same time, due to the decrease of the consolidation force of the central consolidation area, the consolidation force of the annular consolidation area around the central consolidation area is also increased to the entire circumference. A propulsion method used in soft ground that is characterized by uniformly weakening the ground, moving the earth and sand in the annular consolidation area from the entire circumference to the central consolidation area, and discharging it behind it through a reduced diameter pipe for earth and sand discharge.