EP0039474B1 - Immersion vibrator - Google Patents

Abstract

A deep vibrator includes a propulsion head (1) vibrating in a transverse direction with respect to the longitudinal axis of a suspension tube propulsion head being secured to the lower end of a suspension tube (2) while the outer wall of the suspension tube (2) includes pipes (4) arranged in the longitudinal direction thereof having at the lower end of the propulsion head (1) a spraying nozzle through which water may be fed under pressure, further spraying nozzles being distributed along the length of the pipes (4,5) and so aligned that they spray water into the annular space surrounding the suspension tube (2) thereby washing ground material toward the propulsion head.

Description

The invention relates to a deep vibrator with a driving head which swings in the horizontal direction via a driven eccentric and which is fastened to the lower end of a suspension tube, spray tubes extending in the longitudinal direction of the deep vibrator being fastened with a spray nozzle provided at the lower end of the driving head which can be fed under pressure water.

Deep vibrators of this type are used for the production of material columns in the ground, for example drains, plugging, concrete piles and the like. For this purpose, the deep vibrator is driven into the ground to the desired depth with its driving head driven to vibrate. The deep vibrator is then pulled out of the ground again using a suitable lifting device, and at the same time suitable filler material is introduced into the resulting cavity by the deep vibrator.

A deep vibrator with the features mentioned at the outset is known from the magazine "Construction Machine and Construction Technology", 1957, Issue 12, pages 411-413. This deep vibrator works in such a way that when the deep vibrator is sunk into the ground, its propulsion head is driven to vibrate in the horizontal direction via the eccentric. As a result, the jacking head creates an annular space that is essentially free of soil in the soil surrounding it, so that it can be sunk into the soil due to its own weight and supported by the pressurized water emerging at its tip.

However, this previously known deep vibrator works with a relatively low efficiency, measured in terms of the length covered during the lowering per unit of time, since the mentioned annular space around its jacking head is not filled with sufficiently solid material in operation in order to adequately accommodate the horizontal vibrations of the eccentric or the jacking head To be able to transfer mass to the earth surrounding the propulsion head, so that this earth is not displaced there sufficiently, with the disadvantage of a relatively low lowering speed of this deep vibrator.

A deep vibrator is known from FR-PS 1 277 369, which is set into vertical vibrations by an oscillator placed on its upper side. In order to prevent or at least reduce adherence of the deep vibrator to the earth surrounding it when it is sunk and pulled out of the earth, there is also provision for pressurized water to emerge radially through openings which are formed in the casing of the device.

FR-PS 455 730 describes a similar device in which the body to be lowered is surrounded by a tube cage in which spray nozzles are formed.

What the two last-mentioned devices have in common is that they are driven into the ground by vibrations in the vertical direction. There should therefore not be an annular space at the lower end of these devices which would facilitate lowering the devices into the ground.

Starting from a deep vibrator of the type mentioned at the outset, the object of the invention is to design it in such a way that its sinking speed and, if appropriate, its pulling speed are appreciably increased.

To achieve this object, the invention is characterized in that the spray tubes are also led up along the suspension tube and that further spray nozzles are provided distributed over the length of the spray tubes and are oriented such that they spray the water into the annular space surrounding the suspension tube.

As a result of tests which have been carried out in sandy soils, these measures, which are simple to construct, achieve an approximately three times higher sinking speed of the deep vibrator compared to the previously known deep vibrator discussed above. This is essentially due to the fact that the soil surrounding the pipe is loosened by the water flowing there under pressure over the length of the suspension pipe and is flushed down to the jacking head. This soil thus fills the annular space around the head with solid material, in particular sand, and in this way has the effect that the vibrations of the head are transferred very effectively to the soil surrounding the head, so that the head has a sufficiently large annular space to lower the deep vibrator can create in a very short time. Tests have shown that the water present there does not interfere with these processes, possibly because it penetrates the surrounding soil sufficiently quickly. The above-mentioned characteristic measures also ensure that the soil around the hanging pipe is kept constantly moist, so that the sludge that forms forms a kind of lubricant that prevents the hanging pipe from sticking when the deep vibrator is brought down and also when it is subsequently pulled out. Sandy soils in particular are thus loosened in the vicinity of the hanging tube, so that, as tests have shown, material columns over approximately 10 meters deep can be produced with difficulty and at high speed with the novel deep vibrator.

The distance between the spray nozzles should be chosen so large that the annular space around the suspension tube is sufficiently moistened; a distance of about 15 to 25 cm between the spray nozzles has proven to be sufficient. The spray nozzles should be provided essentially over the entire length of the suspension tube. In general, two spray tubes arranged diametrically opposite one another are sufficient to feed the annular space. However, more spray tubes can also be provided distributed uniformly around the suspension tube.

For reasons of stability, it is preferred if the spray tubes are welded to the suspension tube.

The spray nozzles of the spray pipes should spray the water approximately in a tangential direction with respect to the suspension pipe, because then the best efficiency is achieved and because then the impairment due to the part of the spray pipes not yet sunk into the ground is the least.

It can also be provided that the spray tubes are divided in the longitudinal direction of the suspension tube into groups that can be fed separately with the pressurized water. Only those groups are then supplied with spray water that are at least partially sunk into the ground, so that spray water is not uselessly sprayed over the ground. These groups of spray pipes should be angularly offset from one another in a plan view of the suspension pipe, so that there is space for the supply lines for the pressurized water for the spray pipes.

• Fig. 1 schematisch in einer Seitenansicht die wesentlichen Bauelemente eines neuartigen Tiefenrüttlers;
• Fig. 2 ebenfalls schematisch einen Schnitt längs der Linie 11-11 von Fig. 1, wobei zusätzlich eine zweite Gruppe von Sprührohren angedeutet ist.

The invention is explained in more detail below on the basis of exemplary embodiments, from which further important features result. It shows:

• Figure 1 shows schematically in a side view the essential components of a novel deep vibrator.
• Fig. 2 also schematically shows a section along the line 11-11 of Fig. 1, wherein a second group of spray tubes is additionally indicated.

Figure 1 shows the essential components of a deep vibrator, namely a head 1, which is attached to the lower end of a suspension tube 2. A lifting device, not shown, engages a flange 3 of the suspension tube.

Spray pipes 4 are welded to the wall of the suspension tube and have nozzles distributed over their length, which deliver water in the direction of the arrows, i.e. spray essentially tangential to the suspension tube 2. In general, two spray tubes arranged diametrically opposite one another are sufficient.

A second set of such spray tubes can also be provided, which are indicated at position 5 in FIG. 2. As a result, two groups of spray tubes 4, 5 are formed, which can be fed separately with pressurized water. The pressure lines for the supply of water to the spray pipes are not shown.

The nozzles of the spray tubes are arranged at intervals of between approximately 15 and 25 cm.

The innovative deep vibrator is particularly suitable for use in sandy soils at greater depths above about 10 m.

Tests have shown that with the new deep vibrator, material columns up to 25 m deep could be produced without any problems, in a floor where conventional deep vibrators could only be used up to a depth of about 15 m.

Claims (5)

1. Deep hole vibrator with a driving head (1), oscillating in a horizontal direction by means of a driven eccentric, which is secured to the lower end of a suspension pipe (2), while to the outer wall of the deep hole vibrator there are secured spray pipes (4) extending in its longitudinal direction, with a spray nozzle provided at the lower end of the driving head (1), through which water under pressure can be supplied, characterised in that the spray pipes (4, 5) are also led upwards along the suspension pipe (2), and that further spray nozzles are provided, distributed along the length of the spray pipes (4, 5), and are so arranged that they spray the water into the annular space surrounding the suspension pipe (2).

2. Deep hole vibrator according to claim 1, characterised in that the spray pipes (4, 5) are welded onto the suspension pipe (2).

3. Deep hole vibrator according to claim 1 or 2, characterised in that the spray pipes (4, 5) in the longitudinal direction of the suspension pipe (2) are subdivided into groups which can be supplied separately with the water under pressure.

4. Deep hole vibrator according to one of claims 1 to 3, characterised in that the spray nozzles spray the water in the tangential direction relative to the suspension pipe (2).

5. Method of sinking and possibly withdrawing a deep hole vibrator into or respectively out of earth, preferably containing sand, wherein the deep hole vibrator has a suspension pipe (2), to the lower end of which is secured a driving head (1) which is excited in a horizontal direction into oscillations, and which is excited into horizontal oscillations during sinking and possibly withdrawal, wherein at the same time water under pressure emerges in the zone of the tip of the driving head, characterised in that the operation of the driving head is assisted by water, while is supplied under pressure from the suspension pipe (2) into the ground surrounding the suspension pipe and which has the effect that particles of the ground which is there enter the annular space surrounding the driving head (1).

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