JPH0369728A - Earth backfilling method in drawing sheet pile - Google Patents

Abstract

PURPOSE:To enable hydraulic filling to be sufficiently performed over the whole space by inserting a pipe into a space to a specified depth after a sheet pile is drawn out, and by pressure-feeding air or water to the pipe. CONSTITUTION:Pipes 2 are connected to each other in order, and at the tip, a nozzle adapter 3 is fitted, and at a base end, a high pressure hose 5 is fitted via a flow rate regulating valve 4. After that, in case of insertion, pipes 2', 2' are connected one after another, and at the same time, they are slidably inserted into the guide hole 7 of a bearing trestle 6 with bearing legs to be freely folded. After that, to the pipes 2, air and/or water is pressure-fed by a high pressure pump, and is pressure-fed from the nozzle adapter 3 at the tip. Besides, at the same time, or before or after it, at an on-ground section, a drawn-out space is filled up with backfilling earth together with injection water for hydraulic filling, in the state of muddy by water.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for backfilling with earth and sand when pulling out sheet piles.

``Prior art, problems to be solved [51] In general, in mountain retaining excavation work near important structures etc., when removing the retaining wall, the pile removal gap is There is a need to manage construction work to avoid negative effects on the surrounding area, such as backfilling and ground subsidence.

For this reason, the conventional method of filling gaps created after pulling out sheet piles with water at the above-ground level and filling them with top sand for backfilling has been carried out, but it has not been possible to obtain a sufficient water tightening effect over the entire gap. First, there was the problem of considerable subsidence of the surrounding ground.

"Means for Solving the Problems" In order to solve the above-mentioned conventional problems, the present invention provides a structure in which a pipe with a nozzle adapter attached to its tip is slidably supported on a support frame in the gap created after the sheet pile is pulled out. The pipe is sequentially connected and inserted to a predetermined depth, and air, water, or air and water is forced into this pipe and sprayed from the nozzle adapter at the tip, while backfilling the gap above ground with earth and sand. This paper proposes an earth and sand backfilling method that achieves a sufficient water tightening effect over the entire gap and reliably prevents subsidence of the surrounding ground.

"Embodiments" Below, embodiments of the present invention shown in the drawings will be described.
When backfilling the gap created after pulling out the sheet pile I, the pipe 2 is inserted in advance into this gap to a predetermined depth.

The vibrator 2 has a diameter of 12 am, for example, as shown in FIG.
It consists of unit pipes 2 with a length of about 3 to 4 meters connected in sequence at the front and back, and a nozzle adapter 3 is attached to the tip of the unit pipes 2.
Also, fi at the proximal end! , a high pressure hose 5 is attached via a volume control valve 4.

When inserting the unit pipes 2', as shown in Fig. 3, the unit pipes 2' are successively connected and then slidably supported and inserted into the guide holes 7 of the support pedestal 6 whose supporting legs are foldable. Can perform insertion work.

To the vibrator 2, air or water, or air and water, is force-fed by a high-pressure pump and injected from the nozzle adapter 3 at the tip, and at the same time or around the same time, the pull-out gap is backfilled in the above-ground part and water tightened. Fill with muddy water along with water injection.

In this case, the nozzle adapter 3 at the tip should be selected to have a different diameter of injection port depending on the target ground and the object to be pumped.For example, in the case of air injection, the target ground is sandy soil with coarse particle gaps. If the target ground is a layer of clayey soil, use one with a relatively large injection diameter (for example, around 91I■), and if the target ground is a layer of clayey soil with dense particle gaps, use one with a relatively small injection diameter (for example, around 2 to 3ts). Furthermore, in the case of water injection, regardless of whether the soil layer is sandy or clayey, the injection diameter must be relatively small (
For example, it is effective to use 2-3-1).

In this way, by injecting air or water, or both, in the lower part of the gap, the backfilling earth and sand filled with the water injected in the above ground part are stirred, and the backfilling earth and sand is evenly and densely filled over the entire gap, A sufficient water tightening effect can be obtained.

Figure 5 shows the results of a backfilling experiment after pulling out sheet piles using the conventional construction method and the construction method of the present invention in a certain sand layered ground (amount of subsidence in the surrounding ground at intervals of 1.5 m after half a day). This is what is shown.

Since the site had a loose sand layer below G, L and -8m, the test was carried out by using a pipe of the present invention with a diameter of 12mm and a length of 8m and injecting air and water from the tip.

From this result, the conventional construction method (water tightening only in the above ground part)
showed a maximum subsidence of 104 mm (No. 1), whereas the construction method of the present invention using air injection showed a settlement of G, L, -8
The water tightening of the sand layer shallower than 1.5 m was effectively carried out by air, and the amount of subsidence was the smallest at a maximum of 27 am (No. 1).

On the other hand, with the water injection method of the present invention, the water tightening effect was improved compared to the conventional method.
The result was 9 mm (No. 1), which was larger than the case using air injection.

"Effect of Irrigation Lj" As described above, according to the present invention, a sufficient water tightening effect can be obtained over the entire gap, and subsidence of the surrounding ground can be reliably prevented.

[Brief explanation of drawings]

Figure 1 shows the construction state of this invention! FIG. 2 is an exploded front view of a pipe used in this invention; FIG. 3 is a perspective view of a pipe support frame used in this invention; FIG. 4 is a front view showing the pipe in its folded state; FIG. 5 6 is a plan view showing a comparative experimental situation of the present invention, and FIG. 6 is a perspective view showing an outline of a conventional construction state. l... Sheet pile, 2... Pipe, 3... Nozzle adapter, 4... Flow rate adjustment hartz, 5...
・High pressure hose, 6. Support frame, 7. Guide hole. Figure 6 Figure 2 Figure 9'-3

Claims (1)

[Claims] 1) Insert pipes with nozzle adapters attached to their tips that are slidably supported on a support frame into the gap created after pulling out the sheet pile, connecting them one after another to a predetermined depth, and then supply air or water, or air and water, to the pipes. A method of backfilling earth and sand when pulling out a sheet pile, characterized in that the gap is filled with backfilling earth and sand together with water injection while being forcedly fed and injected from a nozzle adapter at the tip.