JPH03151412A - Vertical drain method and permeable structure therefor - Google Patents

Abstract

PURPOSE:To prevent entering of soil grain and to maintain drain function during a long period of time by applying a coating agent mainly composed of an interfacial active agent to the surface of a net bag of a flexible sand drain to make a permeable net bag. CONSTITUTION:A net bag 1 is formed by weaving a fiber yarn 2 like a net. A coating agent mainly composed of an interfacial active agent is applied to the surface of the weaving yarn 2 of the net bag 1 in the final process of a manufacturing process to make a permeable bag which is negatively charged to the same pole side as the negative charge of soil grain in the ground. Thus, in a vertical drain method, soil grain can be prevented from entering the net bag 1 by the ion activation action, and good drain function can be maintained during a long period of time.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention aims to promote the dewatering of soft ground, particularly sticky ground, by forming sand columns (hereinafter referred to simply as "sand" in the sand drain construction method). ) or a columnar body made by filling a net bag with sand (hereinafter, the columnar body in the bagged sand drain method will be simply referred to as ``a columnar body made by filling a net bag with sand''). ) Furthermore, it relates to a cardboard body (hereinafter, the cardboard body in the plastic board drain method will be simply referred to as a "cardboard body"), which is a shape in which the outside of the plastic core material is sealed with a non-woven fabric, and furthermore, This relates to a construction method for improving soft ground using a structure.

<Conventional technology> In the conventional flexible sand drain construction method, a woven fabric of a certain density is made of botethylene yarn as a material, a net bag is formed from the woven fabric, and the net bag is used to construct a sand pillar. It has been used for net bags.

Further, the cardboard body used in the plastic board drain method has a core portion made of a plastic material, and a portion of the filter sealed with, for example, polyester woven fabric.

<Problem to be solved by the invention> Traditionally, sand has been necessary in the flexible sand drain method, but in recent years the properties of the sand used as filler have deteriorated, and more and more sand spills out of the mesh of the mesh bag. As a result, workability deteriorated considerably.

In addition, in the conventional plastic board drain construction method, the water permeability of the nonwoven fabric that serves as the filter decreases over time.
There were drawbacks such as the phenomenon of clogging of the surface of the nonwoven fabric.

The purpose of the present invention is to overcome the drawbacks of these construction methods by improving the properties of the net bag and the nonwoven fabric used as the filter material, thereby maintaining good drain function over a long period of time.

<Means for Solving the Problems> In order to achieve the above object, it is necessary to reduce the frictional resistance between the outer surface of the mesh bag of the flexible sand drain of the present invention and the inner surface of the steel pipe. Therefore, the present invention has been developed by applying a surfactant to the surface of the yarn of the net bag so that after the steel pipe is pulled out and the net bag is installed in the ground, the clay particles have the property of being negatively charged without ionic bonding. The net bag itself is made suitable for achieving the object of the present invention by subjecting it to a surface treatment or by weaving the net bag with yarn having a negatively charged property.

In addition, in order to achieve the above objective in the plastic board drain construction method, it is necessary to make the cardboard body so that it has the property of being negatively charged to prevent ionic bonding of clay particles in the ground when the cardboard body is buried in the ground. It is preferable to subject the surface of the nonwoven fabric that is the filter material to a surface treatment using a surfactant, or to form the nonwoven fabric itself from a material suitable for achieving the object of the present invention.

<Example> As a surface treatment method for net bags and non-woven fabrics, by adding a coating agent mainly consisting of a surfactant to the final step of the product manufacturing process, net bags and non-woven fabrics that are negatively charged in the ground can be made. By using the above-mentioned surface-treated net bag and nonwoven fabric in the vertical drain construction method, the intrusion of clay particles can be prevented through ionic activation.

<Effects of the Invention> Since the present invention has the configuration described above, it is possible to use sand mixed with a somewhat viscous overlay in the flexible sand drain construction method, and costs can be reduced.

In addition, the occurrence of defective drains is reduced, and workability and reliability are improved.

In addition, the plastic board drain construction method eliminates the clogging phenomenon on the filter surface, resulting in improved drainage function as a drain, and has the effect of maintaining good drainage function over a long period of time. Furthermore, when the plastic board drain body is cast, clogging between the earth and sand and the filter material at the tip of the casing is prevented, and the reliability of construction is greatly improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a net bag used in construction using the bagging sand drain method according to the present invention, FIG. 2 is an enlarged view of a portion of the net bag in FIG. 1, and FIG. FIG. 2 is a perspective view of a filter used in construction using the plastic board drain construction method. 1 Net bag 2 Fiber thread 3 Filter cover 7-(Rizu)

Claims (1)

[Claims] 1. A permeable structure for vertical drain construction method, which is formed by negatively charging the permeable structure so that the same polar side as the negative charge of the soil particles in soft ground 2. Soft permeable structure A net bag 1 whose surface has been subjected to a surface treatment such that it is negatively charged in the ground, or a net bag woven so that the surface of the fiber yarn 2 of the net bag 1 is negatively charged in soft ground. The net bag structure 3 for the flexible bag sand drain construction method according to claim 1, which is filled with sand or a material with good drainage performance in place of sand, The plastic board drain construction method according to claim 1, comprising a non-woven fabric filter 3 that has been subjected to a surface treatment so as to be electrically charged, or a filter that is configured to negatively charge the surface of the non-woven fabric material 4 in soft ground. A plastic board drain body 4 for use in the construction of a water-permeable structure is installed in soft ground, and the water-permeable structure is placed on the same polar side as the negatively charged soil particles located around it to prevent clogging. Vertical drain construction method 5, in which a negatively charged plastic board drain body is placed in soft ground at a desired depth, and soil particles located around the plastic board drain body in the soft ground are The plastic board drain construction method 6 according to claim 4, characterized in that the negative charge is the same as the negative charge of the soil particles, or the negative charge is close to the negative charge of the soil particles. A negatively charged net bag structure for the bagging sand drain method is filled with sand and cast to a desired depth, and the soil particles located around the net bag of the sand packed net bag structure are filled with sand. The bag sand drain construction method according to claim 4, characterized in that the soil particles have a negative charge that is the same as the charge or a negative charge that is close to the negative charge of the soil particles.