JPH0472924B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a construction method for covering ultra-soft ground with soil.

(Conventional technology) The conventional soil covering method for this type of ultra-soft ground is as follows:
There is a method in which a sheet or a combination of a sheet and a rope net or the like is stretched out on the ground, the ends of the sheet or rope are fixed with anchors, and then the earth is embanked on top of the sheet.

(Problems to be Solved by the Invention) However, the above-mentioned method has the disadvantage that the thickness of the embankment layer tends to be uneven due to the swelling phenomenon of the soft layer during loading, making the construction unstable.

Another method is to use a sheet or a rope net, etc., connected to the floating body, but it is difficult to connect the floating body to the sheet, etc. on site on soft ground with poor footing. If it is fixed to a container, there is a problem that it is bulky and requires a lot of effort for transportation, loading, unloading, etc.

Furthermore, when using a floating body to perform a consolidation method such as a vertical drain method after embankment, the buoyancy of the floating body acts to reduce the live load, so extra live weight is required, which is unnecessary. It has the disadvantage of being an economy.

(Means for Solving the Problems) The present invention has been made to solve the above-mentioned drawbacks and problems of the conventional method. This lattice-shaped floating body is assembled on site, and the inside of this lattice-shaped floating body is communicated with each other in a predetermined area, and the outside is communicated with a vertical pipe installed in at least one pipe joint. After expanding sequentially to cover the desired area on ultra-soft ground, and then spreading the sheet over this lattice-shaped floating body, embankment is performed on the sheet in sequence, and when carrying out the consolidation method, the lattice is Water is injected into the inside of the floating body to eliminate buoyancy.

(Function) Since the present invention is as described above, according to this earth covering method for ultra-soft ground, the thickness of the embankment layer is kept almost uniform to stabilize the construction, and the transportation, loading, and unloading of materials can be carried out. This not only makes it easier to carry out the work on-site, but also allows the buoyancy of the floating body to be easily eliminated when consolidation methods are implemented.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 shows various pipe joints used in the present invention, and numeral 1 indicates pipes of unit length connected by these pipe joints. The pipe joint a shown in Fig. 1a connects four pipes 1 that are perpendicular to each other in a plane and communicates the insides of all the pipes 1, and the pipe joint a shown in Fig. 1b Pipe joint c in the figure c has one of the communicating holes in pipe joint a closed, and the other communicating hole in pipe joint b is closed, and two orthogonal holes in pipe joint b are closed. Only the pipes are connected to each other, and the pipe joint d in the figure d connects the four pipes 1 connected by the pipe joint c.
Another pipe 1 (indicated by a dotted line) which is perpendicular to the plane including the pipe 1 is further connected to the pipe 1 so as to communicate with the two communicating pipes.

Furthermore, the pipe joint e shown in FIG. joint f
, one communicating hole of pipe joint e is closed to connect two orthogonal pipes 1, and pipe joint g in the figure g connects three pipes connected by pipe joint f. Another pipe 1 (indicated by a dotted line) that is orthogonal to the plane containing the pipe 1 is further connected to the pipe 2 that is in communication with the pipe 1.
It was designed to communicate with the book pipe.

In addition, the pipe joint h in FIG. Another pipe 1 (indicated by a dotted line) which is perpendicular to the pipe 1 is further connected and communicated with the other pipe 1 (indicated by a dotted line).

The materials of the pipe 1 and the various pipe joints a to h described above are not particularly limited, but synthetic resins such as hard vinyl chloride are suitable.

Figure 2 is a plan view showing an embodiment of the construction method of the present invention.
FIG. 3 is an elevational sectional view thereof. Also, Figure 4 shows the second
In the partial plan view of the figure, FIGS. 5a and 5b are elevational cross-sectional views of each step in FIG. 4.

In the figure, 2 is the conventional ground or dam, and 3 is the extremely soft ground.

In this example, the various pipe joints a to h described above and the pipe 1 of unit length are used to obtain a desired area, for example, within the area A ₁ of each section divided by the two-dot chain line in FIG. A lattice-shaped floating body is assembled on site, and this lattice-shaped floating body communicates with the inside of each predetermined area and with the outside through a vertical pipe 4 erected in at least one pipe joint. In section _A1 of FIG. 2, a vertical pipe 4 is connected to pipe joints h and d.

The lattice-shaped floating body is constructed by connecting a large number of pipes 1 via various pipe joints a to h. This pipe 1 and pipe joints a~h
Although any method may be used for joining, it is necessary to join them airtightly. For example, the fitting portion may be airtightly joined using an adhesive.

As shown in Fig. 2, the grid-like floating body as described above is divided from the area A ₁ to the area A 2 adjacent to the area A ₂ ,
After sequentially expanding A ₃ , A ₄ , etc. to cover the desired area on the ultra-soft ground 3, spread out the sheets 5 (see Figures 3, 4, and 5) on these lattice-shaped floating bodies. 5 with strings 6 (see Figure 4), and if necessary, the sheet 5 and the grid-like floating body are connected with wires 7 (see Figure 4), etc., and then embankments 8 are sequentially placed on the sheets 5. I do.

In this case, the upper end of each vertical pipe 4 has a lid 9.
Keep it closed to prevent dirt from entering. Further, as shown in FIG. 5, if necessary, anchors 10 are driven into the ends of the lattice-shaped floating body to fix the lattice-shaped floating body and the sheet 5. Fig. 5a shows the state before embankment is carried out, Fig. 5b shows the state in the middle of embankment, and Fig. 3 shows the state when embankment is completed.

After embankment, when performing a consolidation method such as a vertical drain method, the lid 9 of each vertical pipe 4 is removed and water is injected into the inside of each lattice-shaped floating body from this pipe 4. In order to improve this water injection efficiency, it is preferable to provide vertical pipes 4 at diagonal positions on the outside of the lattice-shaped floating body so that water is injected from one pipe 4 and air is removed from the other pipe 4.

When the water injection into the lattice-shaped floating body is completed as described above, the buoyancy of the lattice-shaped floating body disappears, so that the effectiveness of the applied load in the consolidation method is no longer reduced.

In order to increase the buoyancy of the lattice-shaped floating body, either shorten the length of the pipe 1 and reduce the lattice spacing, or
The diameter of the pipe 1 may be increased, or a plurality of lattice-like floating bodies may be formed and stacked one above the other. The greater the buoyancy of the floating body, the more the embankment layer 8
The thickness can be increased.

FIG. 6 shows an example in which lattice-shaped floating bodies are stacked in three layers, and in the figure, the same reference numerals as those mentioned above indicate equivalent parts. However, in this case, the vertical pipes 4 interposed between the second and third lattice floating bodies from the bottom
It is preferable to use pipe joints d' for joining the vertical pipes 4 to which the vertical pipes 4 can be connected, respectively.

7 to 9 are plan views showing various methods of forming lattice-like floating bodies in the construction method of the present invention, and in the figures, the same reference numerals as those described above indicate equivalent parts. Note 1
1 is the water edge between the conventional ground 2 and the ultra-soft ground 3.

Fig. 7 is suitable for cases where the ground 3 created by the water conveyance method etc. has a relatively high consistency. After assembling it to a size of It shows.

In addition, Figures 8 and 9 show that the ground 3 created by the water conveyance method has almost no consistency and is suitable for cases where there is water. Lattice floating body assembled to size 15
Scaffolding boards 13 are lined up on top to form a raft, and this raft is launched from above ground 2 onto ground 3 using a lever rod, and then adjacent to it, a lattice-shaped floating body 15 assembled in the same manner is launched. A raft consisting of a scaffolding board 13 is launched from the ground 2 onto the ultra-soft ground 3.

As described above, as shown in FIG.
While transporting the grid-shaped floating bodies 15 in order to positions G and H, the grid-shaped floating bodies 15 are connected by connecting pipes 16, and finally, the grid-shaped floating bodies 15 are also arranged at positions I and J,
All floating bodies 15 are connected by connecting pipes 16.

After all the lattice floating bodies are connected, the ground 3
If the above water is drained, the floating body will be laid on mud, so after spreading the sheet 5 on this floating body,
Embankment 8 may be performed from the conventional ground 2 side.

(Effects of the Invention) As mentioned above, the construction method of the present invention forms a lattice-like floating body with the pipe 1 through various pipe joints a to h, and this is laid on the ultra-soft ground 3, so it is different from the conventional construction method. The rigidity of the lattice-shaped floating body is greater than that of a sheet or rope net laid directly on ultra-soft ground, so local swelling of the ground during loading is reduced, and as a result, the thickness of the embankment layer is reduced. This results in uniformity and stable construction.

In addition, since the materials such as pipe 1, various pipe joints a to h, and sheet 5 can be brought to the site and assembled on site, it is easy to transport, load, and unload the materials. For assembly, the pipe 1 may be fitted into the various pipe joints a to h using an adhesive or the like, so that the assembly work is facilitated.

In addition, since the above-mentioned lattice-shaped floating body can easily increase or decrease the buoyancy, it can easily respond to the adjustment of the height of the embankment.

Furthermore, since the lattice-shaped floating body constructed using the method of the present invention communicates between the inside of each predetermined area and the outside through a vertical pipe erected at at least one location, even if a part of the lattice-shaped floating body is damaged for some reason. However, the buoyancy of the lattice-shaped floating body in that part is only lost, but the buoyancy of other parts of the lattice-shaped floating body does not disappear, so there is no risk that the buoyancy of the entire lattice-shaped floating body will disappear.

When implementing the consolidation method after embankment, the buoyancy of the lattice-shaped floating bodies can be eliminated by injecting water into each lattice-shaped floating body through the vertical pipes, so extra loading weight is required. You can get the effect that there is no problem.

[Brief explanation of drawings]

Figures 1 a to h are plan sectional views showing various pipe joints used in the construction method of the present invention, Figure 2 is a schematic plan view showing the construction method of the present invention, Figure 3 is an elevational sectional view thereof, and Figure 4
The figure is a detailed view of a part of FIG. 2, FIGS. 5a and 5b are elevational sectional views thereof, FIG. 6 is an elevational sectional view showing another embodiment, and FIGS. 7 to 9 are examples of the construction method of the present invention. FIG. 1...pipe, a~h...pipe joint,
2... Conventional ground, 3... Super soft ground, 4... Vertical pipe, 5... Sheet, 6... String, 7... Wire,
8... Embankment, 9... Lid, 10... Anchor, 11
...waterline, 12...lattice-shaped floating body, 13...scaffolding board, 15...lattice-shaped floating body, 16...connection pipe.

Claims (1)

[Claims] 1 A lattice-shaped floating body with a desired area is assembled on site using various pipe joints and pipes of unit length, and this lattice-shaped floating body has internal communication for each predetermined area and at least one pipe. It communicates with the outside through a vertical pipe installed at the joint.
This lattice-shaped floating body is sequentially expanded on site to cover the desired area on the ultra-soft ground, and then sheets are spread over this lattice-shaped floating body, and then embankment is sequentially performed on the sheet to implement the consolidation method. An earth covering method for ultra-soft ground characterized by sometimes injecting water into the interior of the grid-like floating body from the vertical pipe to eliminate buoyancy.