JP2743031B2 - Liquefaction countermeasures - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a construction method capable of dispersing excess pore water generated during an earthquake and preventing liquefaction of sand ground.

<Prior Art> It is known that a sand ground liquefies during an earthquake and destroys a structure.

For this purpose, methods have been developed to increase the strength by compacting the ground, or to vertically drive crushed stone or synthetic resin drain material into the ground to dissipate excess pore water generated during an earthquake.

<Problems to be Solved by the Present Invention> A conventional drain material made of synthetic resin is a single band-shaped plate.

Therefore, the effective range of calculation for one drain material is extremely small.

For example, when a drain material having a cross section of about 10 cm × 4 cm is embedded in the ground, it is merely converted into a cylindrical well having a diameter of about 5 cm.

<Object of the present invention> The present invention has been made to improve such a conventional problem, and instead of a conventional plate-shaped drain material, a radial drain material is used to form a ground well having a large diameter. It is an object of the present invention to provide a construction method capable of preventing liquefaction.

<Means for Solving the Problems> That is, the present invention forms a radial drain material by connecting the longitudinal edges of a plurality of belt-shaped water-permeable materials, and inserts a plurality of the drain materials into the ground to form a drain. This is a liquefaction countermeasure method in which a honeycomb member having a vertical water passage is disposed on the upper surface of the material group, and a structure is mounted on the honeycomb member.

<Description of the present invention> Hereinafter, the present invention will be described in detail. First, a drain material that can be used in the method of the present invention will be described.

<A> Water-permeable wing plate The drain material of the present invention is composed of a plurality of water-permeable wing plates 1.

The water-permeable wing plate 1 includes a core material 11 and a covering material surrounding the core material 11.
And 12.

The core material 11 is a band-shaped synthetic resin plate having a sufficient length.

Then, in particular, a concave portion or a convex portion is formed in the longitudinal direction to form the water channel 11.
a is secured.

The core material 11 is a synthetic resin product having moderate rigidity,
As will be described later, since the bent edge is formed by a coating material having no rigidity, winding by a roller is sufficiently possible.

The covering material 2 surrounding the periphery of the core material 11 is also a net made of synthetic resin.

The covering material 2 surrounds the periphery of the water channel 11a, and secures a long function as a water passage in the ground.

<B> Assembly of Blades A bent edge 3 is provided at one edge in the longitudinal direction of the blade 1 having the above structure.

Since the core material 11 is not enclosed inside the bent edge 3, there is no rigidity.

A plurality of blades 1 having the above structure are positioned in parallel, and the bent edges 3 are collected and joined to each other.

As a result, the plurality of water-permeable vane plates 1 are radially arranged around a straight line in a freely bendable state.

This is the drain material of the present invention. For example, if four water-permeable wing plates 1 are collected, a drain material having a cross-shaped cross section can be formed.

<Usage Method> Next, a liquefaction countermeasure method using the above drain material will be described.

<B> Pushing into the ground Drain materials cannot be directly pushed into the ground because they have a moderate flexibility.

Therefore, the drain column 6 is formed by being pushed into the ground with its surroundings protected by a device called a mandrel similarly to the conventional drain material.

<B> Pushing device The pushing device for pushing the drain material of the present invention into the ground can basically use a conventional device as it is.

However, as shown in FIG. 4, the outside is protected by an outer cylinder 4,
The inside of the cylinder has a structure that houses a cross-shaped cylinder.

Of course, if the drain material is not cross-shaped, an inner cylinder having a shape corresponding to the developed shape is adopted.

The outer cylinder 4 is mounted on the body 41, and the drain material of the present invention is stored in the cross-shaped cylinder.

And when the outer cylinder 4 is pushed vertically into the ground with hydraulic pressure,
The drain material wound up in a roll shape as a parallel plate as shown in FIG. 2 is developed in a cross shape as shown in FIG.

Then, the tip is pulled and sequentially pushed into the ground to form the drain column 6.

<C> Laying of Honeycomb Disk Body The honeycomb disk body 5 is a thick disk-shaped body in which hollow hexagonal columns are formed of synthetic resin, and a number of the hexagonal column groups are adhered in parallel.

The honeycomb substrate 5 is laid on the upper surface of a large group of drain columns 6 with the hollow holes in a vertical state.

Actually, since there is no water permeability between the hexagonal column and the adjacent hexagonal column, a nonwoven fabric mat 7 having good water permeability is horizontally laid on the drain column 6 group, and the honeycomb body 5 is placed thereon. It is listed.

<D> Construction of Structure A concrete or steel structure 8 such as an oil tank is constructed on the honeycomb substrate 5 thus configured.

A wall 10 made of a honeycomb member is arranged around the structure 8, a side groove 9 is opened at the upper end thereof, and a part of the bottom of the side groove 9 is opened to be continuous with the honeycomb disk body 5.

<Effect at the time of an earthquake> When the pore water pressure rises at the time of an earthquake, the groundwater penetrates into the permeable vane 1 of the drain column 6 and rises vertically through the internal waterway.

This rising water is temporarily stored in the space inside the hexagonal column of the honeycomb body 5.

Then, when the groundwater exceeds the content in the hexagonal column, the groundwater is discharged from the periphery of the structure into the gutter 9 on the ground.

In this way, even if the pore water pressure in the sand ground rises sharply during an earthquake, groundwater can be quickly discharged, so that fluidization can be prevented.

<Effects of the present invention> Since the liquefaction countermeasure method of the present invention has the above-described configuration, the following effects can be achieved.

<A> The plane shape of the drain post inserted in the ground is not a single character as in the prior art, but a cross shape or other desired number of radial lines.

Therefore, it can be evaluated as a drain well having an extremely large diameter as compared with a conventional one-character drain column.

Therefore, excess pore water pressure generated during an earthquake can be quickly dissipated.

<B> A structure in which the structure is supported by a honeycomb-shaped board laid on the drain material.

Therefore, the excess pore water can be once stored in the space inside the hollow pillars constituting the honeycomb body.

Therefore, the drainage resistance can be made extremely small, and smooth drainage can be performed.

[Brief description of the drawings]

FIG. 1: A perspective view of a wing plate constituting a part of a drain material used in the method of the present invention FIG. 2: A plan view of a folded state of the drain material FIG. 3: A plan view of an expanded state of the drain material FIG. Explanatory drawing of the state of insertion into the ground Fig. 5: Explanatory drawing of a honeycomb disk body Fig. 6: Explanatory drawing of a state in which a structure is supported

Claims (1)

(57) [Claims] 1. A radial drain material is formed by connecting the longitudinal edges of a plurality of belt-shaped water-permeable materials, and a plurality of the drain materials are inserted into the ground. A honeycomb member formed as a board by connecting a large number of rectangular cylinders each having a water passage in the horizontal direction, and further arranging a structure on the honeycomb member;