JP4365514B2 - Drain material and vertical drain method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drain material for draining pore water, and a vertical drain method using the drain material.
[0002]
[Prior art]
As a method for effectively using felled timber generated in construction work such as tunnels, dams, or residential land development, a method of using felled timber in crushed chips has been proposed. For example, as disclosed in Japanese Patent Application Laid-Open No. 11-29383, a method of using a wood chip as a compost material, a method of using a wood chip as a water retention layer of a slope greening material, and the like are known.
However, there are cases where a large amount of felled timber cannot be disposed of only with the above usage method, and there is a demand for a usage method other than the above usage method.
[0003]
Conventionally, a vertical drain construction method is generally known as a soft ground countermeasure construction method. The vertical drain method is a method of promoting consolidation settlement and increasing strength by forming a drainage channel (drainage column) through pore water in soft ground and shortening the drainage distance. Sand or cardboard is mainly used as the drain material constituting the drainage channel.
[0004]
[Problems to be solved by the invention]
However, the conventional vertical drain method has the following problems.
For example, when sand is used as the drain material, there is a concern of causing environmental destruction by sand collection. In recent years, it has become difficult to obtain good quality sand.
In addition, when chemical fiber or the like is used as the drain material, the drain material may remain in the ground semipermanently, which may adversely affect the environment. For these reasons, a drain material excellent in environmental conservation is demanded.
[0005]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a drain material and a vertical drain method capable of effectively using felled timber and excellent in environmental conservation.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the invention described in claim 1 is directed to draining the interstitial water in a vertical drain method that promotes consolidation settlement by forming an interstitial water drainage channel in the ground using a drain material. It is a vertical drain material used as a drainage material, and contains a wood chip formed by pulverizing wood as a main component.
[0007]
According to the first aspect of the invention, since the wood chip is contained as a main component, the pore water can be drained through the gap formed between the wood chips.
In addition, since the wood chip is corroded and assimilated with the soil after that, it is possible to realize a drain material excellent in environmental conservation without adversely affecting the environment.
[0008]
Here, examples of the wood used as a raw material for the wood chip include, for example, logging wood described later, waste wood generated at a construction site, and remaining wood generated at a lumber mill. Good. The part of the wood is not particularly limited, and may be any part such as a trunk, a root, a branch leaf, and an epidermis. Therefore, the wood that has been treated as waste can be used effectively.
In addition, the term “containing wood chips as a main component” includes a case in which the drain material is composed of only wood chips as in the invention described in claim 2, and a mixture of wood chips and other materials. Is included, and is meant to be included. Examples of the other materials include known drain materials and various additives, and these are preferably natural materials such as sand and crushed stone. By doing so, it is possible to further increase the affinity with the environment.
The wood chip may be a uniform wood chip having a uniform size and shape, or a wood chip in which chips of different sizes and shapes are mixed. Further, the shape of the wood chip is not particularly limited, and may be any shape such as a needle shape, a plate shape, or a granular shape. In addition, by changing the size and shape of the wood chip, the size of the gap formed between the wood chips can be changed, and the water permeability as a drain material can be changed accordingly.
[0009]
The invention according to claim 1 is characterized in that the vertical drain material is composed only of the wood chips.
[0010]
Therefore, according to the first aspect of the present invention, the vertical drain material is composed of only wood chips, so that the drainage function is high, and after performing the drainage function, the vertical drain material corrodes and assimilates with the soil. Can be realized.
[0011]
The invention according to claim 2 is characterized in that in the drain material according to claim 1, felled wood is used as the wood.
[0012]
According to the invention described in claim 2, since the felled wood is used for the wood that is the raw material of the wood chip, the felled wood can be reused as an effective resource.
[0013]
Here, the felled timber includes, for example, felled timber generated in construction work such as tunnels, dams, or residential land creation, and thinned wood generated in the thinning operation of plantations.
For example, when reclaiming felled timber generated in construction work as drain material, the amount of waste generated from the site can be reduced, and waste processing costs and material costs for drain materials can be reduced. Can do. In addition, it is possible to avoid environmental destruction associated with securing the drain material.
On the other hand, for example, when the thinning material generated in the thinning operation of the plantation is reused as a drain material, the thinning material left in the plantation can be reduced, and as a result, the afforestation environment can be improved. .
[0014]
The invention according to claim 3 is a vertical drain method for promoting consolidation settlement by forming a drainage channel of pore water in the ground using a drain material, and the drain material is as claimed in claim 1 or 2. The vertical drain material described is used.
[0015]
According to the third aspect of the present invention, the vertical drainage material according to the first or second aspect is used to promote the consolidation settlement by forming the drainage channel of the pore water in the ground. It is possible to effectively use timber such as felled timber that has been used, and to realize a vertical drain method excellent in environmental conservation.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0017]
The drain material S of the present embodiment is, for example, a drain material composed only of wood chips formed by pulverizing felled wood (including roots and branches and leaves) generated in construction work such as tunnels, dams, or residential land development. . A known wood crushing apparatus is used for crushing felled wood.
[0018]
The wood used as the raw material for wood chips should be, for example, thinned wood produced by thinning operations in plantations, waste wood produced at construction sites, or residual wood produced at a sawmill. Is also possible. The wood chip may be a uniform wood chip having a uniform size and shape, or a wood chip in which chips of different sizes and shapes are mixed. Further, the shape of the wood chip is not particularly limited, and may be any shape such as a needle shape, a plate shape, or a granular shape. For example, by changing the size and shape of the wood chips, the size of the gap formed between the wood chips can be changed, and the water permeability as a drain material can be changed accordingly. Therefore, it is desirable to select the size and shape of the wood chip according to the ground condition.
In this embodiment, the drain material S is composed of only wood chips. For example, the drain material S is mixed with wood chips and other materials (for example, sand, crushed stone, various additives). S can also be configured. In that case, it is desirable to use natural materials such as sand for the other materials, and by doing so, affinity with the environment can be improved.
[0019]
Next, an example of the vertical drain method using the drain material S will be described.
[0020]
First, as shown in FIG. 1, prior to the formation of drainage columns 1,... (Vertical drainage channels) by the drain material S, a sand mat 2 (horizontal drainage channel) is formed on the ground surface of the soft ground 4. . That is, sand with good drainage is spread on the ground surface to form a sand mat 2 having a predetermined thickness, and a drainage channel at the boundary surface between the embankment 3 and the soft ground 4 described later is secured.
[0021]
Next, drain columns 1,... (Drains) are formed in the soft ground 4 with a predetermined interval. As a construction method for the drainage pillars 1,..., A publicly known construction method using sand as a drain material, such as a vibratory hammer type, an auger type, a bagging type, or the like, can be applied.
For example, in the case of the vibratory hammer type, the casing is driven to a predetermined depth using the vibration of the vibratory hammer, and the drain material S (wood chips) is put into the casing with a bucket or the like. When the introduction of the drain material S is completed, the casing is pulled out while sending compressed air from the upper part of the casing toward the drain material S. Thereby, the drainage column 1 made of the drain material S can be formed in the soft ground 4.
Here, for example, in order to smoothly pull out the casing, a plurality of types of drain materials may be introduced into the casing. For example, after the drain material S made of wood chips is introduced, a drain material made of sand or crushed stone can be introduced, so that a load can be applied to the wood chips from above, whereby the casing can be pulled out. It can be smooth. It is also possible to increase the packing density of the wood chips.
[0022]
When the formation of the drainage pillars 1,... Is completed as described above, the embankment 3 is created on the sand mat 2. As a result, a desired load can be applied to the soft ground 4 and the consolidation of the soft ground 4 can be promoted. That is, it becomes possible to drain pore water at an early stage.
[0023]
As described above, according to this embodiment, since the drain material S is composed of only wood chips, the drain material S corrodes and assimilates with the soil after performing the drainage function. Therefore, it does not adversely affect the environment.
Moreover, since the felled timber generated in the construction work is used as the raw material for the wood chip, the felled timber can be reused as an effective resource. As a result, the amount of waste generated from the site can be reduced, and waste processing costs and drain material costs can be reduced. In addition, it is possible to avoid environmental destruction associated with securing the drain material.
[0024]
In the above embodiment, the drain pillars 1 are formed in the soft ground 4 with the drain material S made of wood chips. For example, the above-described sand material is made of the drain material S made of wood chips. A drainage layer can be formed in place of the mat 2, or a greening base material is produced by mixing the drainage material S made of wood chips with locally generated soil, seeds or additives, and this is used for the above-described embankment 3 It is also possible to form a water retention layer of slope greening material by spreading on the slope.
Further, for example, when the drain material S made of wood chips is put into a hole having a high groundwater level, the wood chip has a low specific gravity, so that buoyancy works and there is a concern that the hole is not sufficiently filled in the hole. In such a case, draining material S made of wood chips and materials such as sand and crushed stone having a higher specific gravity than wood chips are alternately put in appropriate amounts, so that the wood chips are made of sand or crushed stone. It can be pressed down and the above concerns can be resolved.
Further, the vertical drain method according to the present invention is not limited to the vertical drain method shown in this embodiment, and there may be various variations. For example, the construction procedure of the drainage pillars 1... Shown in this embodiment, the loading method on the soft ground 4 and the like are examples, and can be changed as appropriate.
[0025]
【The invention's effect】
According to the present invention, it is possible to effectively use wood such as felled wood that has been discarded so far.
In addition, it is possible to realize a drain material and a vertical drain method excellent in environmental conservation without adversely affecting the environment.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a vertical drain method as an example to which the present invention is applied.
[Explanation of symbols]
1 Drainage column (drainage channel)
2 Sandmat 3 Filling 4 Soft ground

Claims (3)

In the vertical drain construction method that promotes consolidation settlement by forming a drainage channel of pore water in the ground using a drain material, a vertical drain material used as a drainage material for draining the pore water,
A vertical drain material comprising only wood chips obtained by pulverizing wood.   The vertical drain material according to claim 1, wherein felled wood is used as the wood. It is a vertical drain method that promotes consolidation settlement by forming pore water drainage channels in the ground using drain materials,
A vertical drain construction method using the vertical drain material according to claim 1 or 2 as the drain material.

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