JP3785567B2 - Consolidation promotion method for landfill soft viscous soil layer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for promoting consolidation of a landfill soft and viscous soil layer.
[0002]
[Prior art]
When applying soft clay soil to a disposal site formed by partitioning a dike body on the bottom of the ground, the applicants of the present patent application previously entered the disposal site at a stage where the landfill was not completed. A number of vertical plastic board drain materials that penetrate through the layer of soft viscous soil that was introduced and whose lower ends are anchored to the water-permeable layer on the bottom ground were cut, and the upper ends of these vertical plastic board drain materials were cut In this state, soft viscous soil is added to the appropriate thickness, and in this state, water is absorbed by a bomb from the permeable layer to lower the groundwater level in the disposal site, promoting consolidation of the soft viscous soil layer, and landfill disposal amount of soft viscous soil Has been developed (see JP 2000-234320 A).
[0003]
This conventional technique is applied when a permeable layer is present on the bottom ground of the disposal site. However, when the permeable layer is not present, this conventional technique is applied by providing a permeable layer. Is not a good idea because it increases costs and reduces the amount of soft and viscous soil that can be thrown into the disposal site by the amount of the permeable layer.
[0004]
[Problems to be solved by the invention]
The problem to be solved by the present invention (object of the present invention) is effective and sufficiently soft and viscous when applied to the general case where there is no permeable layer on the bottom of the disposal site in view of the above-mentioned problems of the prior art. An object of the present invention is to provide a method for promoting consolidation of a landfill soft-viscous soil layer capable of increasing the amount of landfill disposal.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, in the method for promoting consolidation of a landfill soft viscous soil layer of the present invention (hereinafter referred to as the method of the present invention), the soft viscous soil is introduced into a disposal site formed by partitioning on the bottom of the ground with a levee body. When the landfill is completed, the vertical plastic board drain material is placed on the landfill soft viscous soil layer at the stage where the landfill is not completed, and the upper end of the vertical plastic board drain material in each row is placed on one side in the atmosphere. After sequentially connecting to the other side of the horizontal plastic board drain material with the impervious sheet attached, and connecting the hose connected to the vacuum pump to one end of the horizontal plastic board drain material, each horizontal plastic board drain material is appropriately Cover it with soft viscous soil for sealing, and operate the vacuum pump in this state to absorb pore water in the soft viscous soil layer and By the action of negative pressure to the sex soil layer, and so as to facilitate its consolidation.
[0006]
That is, in the method of the present invention, the horizontal drain material cooperating with the vertical drain material is the same as the vertical drain material, the plastic board drain material is used, the horizontal drain material with the impermeable sheet stretched on one side surface, Covering and sealing the drain material with soft clay of appropriate thickness, and applying a negative pressure to the soft clay layer with a vacuum pump via the horizontal drain material and vertical drain material, the landfill soft clay soil layer Promotes consolidation.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the method of the present invention will be described with reference to the drawings. In FIG. 1, a disposal site of an appropriate size is provided on the bottom of the ground 1 by dividing it with a dam body (not shown). In the method of the present invention, in the middle of the completion of the landfill of the disposal site, the landfilled soft-viscous soil layer by the softly viscous soil previously introduced into the disposal site. The second consolidation is performed in the following manner.
[0009]
First, the vertical drain members 3 are placed in a row, and the upper ends of the vertical drain members 3 are sequentially connected to the horizontal drain members 5 in the atmosphere above the water surface 4, and caps 6 are attached to both ends of the horizontal drain members 5. 7 is attached so that soft and viscous soil does not enter, and a hose (not shown) communicating with a vacuum pump is connected to the cap 6 at one end (see FIG. 2), and the horizontal drain material 5 is shown in FIG. (The method of the present invention can be applied even when there is no water on the soft-viscous soil layer 2).
[0010]
The vertical drain member 3 and the horizontal drain member 5 are connected to each other by folding the upper end of the vertical drain member 3 to a predetermined position on one side of the horizontal drain member 5 as shown in FIG. In this case, the stoppers 8 and 9 are applied, and the cut-and-raised piece provided in one stopper is inserted into the hole provided in the other stopper over the overlapped portion, and is bent and fixed. The filter material on the surfaces of the vertical drain material 3 and the horizontal drain material 5 in the overlapping portion may be peeled off.
[0011]
As described above, after placing the vertical drain material 3 in each row and connecting / installing the horizontal drain material 5 in sequence, an appropriate thickness (for example, about 1 m) is formed on the soft clay soil layer 2. The soft viscous soil is put in to form a soft viscous soil layer 10 for sealing, and the vacuum pump is operated in this state, and the soft viscous soil layer 2 is mainly formed through the vertical drain material 3 and the horizontal drain material 5. While absorbing and removing pore water, negative pressure is generated and the soft viscous soil layer 2 is consolidated by the action of atmospheric pressure.
[0012]
At this time, pore water in the soft viscous soil layer 10 is absorbed through the horizontal drain material 5 and the soft viscous soil layer 10 is also consolidated. However, the water drainage of the horizontal drain material 5 provides a sealing effect for the soft viscous soil layer 10. Concern to be disturbed is that by using a horizontal drain material 5 with an impermeable sheet stretched on one side surface and connecting the upper end of the vertical drain material 3 to the other side surface of the horizontal drain material 5, a soft viscous soil layer 2 Since the side surface on which the water-impermeable sheet of the horizontal drain material 5 is stretched is the upper surface in a state of being attached to the upper surface, water absorption from the upper soft-viscous soil layer 10 is suppressed, and the concern is wiped out.
[0013]
As described above, after the soft-viscous soil layers 2 and 10 are consolidated, the reclamation is resumed. However, as compared with the case of continuous reclamation without interrupting the reclamation, only the consolidation of the soft-viscous soil layers 2 and 10 is achieved. Extra soft clay can be thrown into the disposal site, and the disposal amount of soft clay can be increased.
[Brief description of the drawings]
FIG. 1 is an overall cross-sectional view for explaining an embodiment of the method of the present invention.
FIG. 2 is a perspective view showing a connection mode of a vertical drain material and a horizontal drain material.
FIG. 3 is an enlarged sectional view of the same.
[Explanation of symbols]
1: submerged ground, 2: soft clay layer, 3: vertical drain material, 4: water surface, 5: horizontal drain material, 6: cap, 7: cap, 8: fastener, 9: fastener, 10: soft viscosity Soil layer.

Claims (1)

When soft clay soil is thrown into the disposal site formed by partitioning on the bottom of the ground with soft dam body, when the landfill is not completed, vertical plastic board drain material is placed on the landfill soft clay soil layer, In the atmosphere, connect the upper end of the vertical plastic board drain material in each row to the other side of the horizontal plastic board drain material with a water-impermeable sheet on one side , and connect it to one end of the horizontal plastic board drain material. After connecting the hose that communicates with the vacuum pump, each horizontal plastic board drain material is covered with an appropriate thickness of soft viscous soil for sealing, and in this state, the vacuum pump is operated to remove the pore water of the soft viscous soil layer. A method for promoting consolidation of a landfill soft viscous soil layer characterized by absorbing water and applying a negative pressure to the soft viscous soil layer to promote consolidation.

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