JPS607092B2 - Sand pile construction method - Google Patents

Description

[Detailed Description of the Invention] A conventional technique for improving soft ground is to penetrate a hollow tube into the ground, insert a bag with a closed bottom end into the hollow tube, and fill the bag with sand. After that, only the hollow pipe is pulled out and sand piles packed in bags are created in the ground.

A technology called the so-called pack drain construction method is known. In the above-mentioned prior art, the entire length of the improved depth is covered with a bag.

However, the bag is unnecessary at depths where the sand piles to be built can stand on their own, and the construction cost is increased accordingly. The applicant of this application previously submitted Tokuiso Sho No. 56-2903 (Application S56-11-8) as a new technology that eliminates the drawbacks of the conventional technology.The technical contents are as follows:
In soft ground, build sand piles whose outer periphery is covered with a permeable cylinder only at depths where the binding force is weak (for example, sand piles are self-supporting or not), and only sand piles are built at other depths. This is a so-called hybrid method of creating continuous sand piles. The construction method of this invention is a further improvement on the above-mentioned new technology. First, an example of the apparatus used in the construction method of the present invention will be explained.

In Figures 1 and 2, numeral 1 is a hollow tube for sand pile construction, and a hopper 2 and a penetrating machine 3 are attached to the upper end of the pipe. In the case of a rotary type drive mechanism, the hopper 2 is circular.

Further, a guide tube 4 is provided at a suitable position within the hollow tube 1, and the upper end of the upper tapered portion of the guide tube 4 is fixed to the inner surface of the hollow tube 1 by means such as welding. Reference numeral 5 in FIG. 3 indicates a wire guide path provided in the tapered part of the guide tube 4. This guide path 5 is provided with a pipe-shaped protective cover 6 in the case shown in the figure, but this cover 6 is not necessarily a pipe. However, the structure is not limited to this, as long as it is structured to block the wire 7 inserted into the guideway 5 from sand.

8 is a short tube provided between the upper end of the hollow tube 1 and the hopper 2; the cover 6 is provided up to this short tube 8, and the wire 7 is drawn out from a hole provided in the cover 6.

As shown in FIG. 2, the wire 7 is guided by a guide sheep 9 provided inside and outside the short switch 8, and is wound up or rewound by a suitable winding drum (not shown).

10 is a water-permeable cylindrical body with a removable hanging fitting 11 at its upper end.
The lower end of the wire 7 is fixed to the metal hook 1.

Further, a ring 12 made of metal, plastic, cardboard, etc. is fixed to the lower end of the cylinder 10. This invention uses the above-mentioned device, and a hanging metal package and a wire 7 are attached to the upper end of a water-permeable cylinder 18 which has been cut to a desired length in advance, and a hollow tube is made as shown in FIG. 4. Open the lozenge 3 at the lower end of 1, pull the cylindrical body 10 into the hollow tube 1 suspended by a crane, and insert the upper end of the cylindrical body 10 between the guide tube 4 and the hollow tube 1 as shown in Fig. 4D. Set together with the hanging metal wing 1.

Next, start the penetrating machine 3, close the lower end diamond pit 3, and penetrate the hollow tube 1 into the ground 14. At this time, it is recommended to supply sand into the hollow tube 1.

In this way, after penetrating the hollow tube 1 to the improved depth as shown in FIG.

This predetermined amount of sand is such that the sand surface is slightly below the lower end of the cylindrical body 0 in the hollow tube furnace, or the sand surface is slightly in contact with the lower end of the cylindrical body 10. Next, while pulling out the hollow tube 1, open the bottom lid 3 and drain the sand inside the tube 1. After pulling out the hollow tube 1, as shown in Fig. 4, remove the sand pile 1.
5 and when the withdrawal of the hollow tube turtle is temporarily stopped with some sand remaining in the hollow tube 1, the upper end of the cylindrical turtle 0 will be 9M above the ground in the illustrated example. .

In this way, while the hollow tube neck is stopped, more sand is thrown into the hollow tube 1, but at this time, as shown in Fig. If the sand is thrown in so that it reaches the ground, the diameter of the cylinder will expand due to the sand, and the overall length of the cylinder 18 will be shortened.
becomes.

Next, while pulling out the hollow pipe 1 as shown in the figure, sand is discharged from the lower end of the hollow pipe 1 into the ground 14 to continue building sand piles, and the sand pile is made as shown in Fig. 4. When the hollow pipe 1 is completely pulled out onto the ground 14 and the construction of the sand pile is completed, the diameter of the cylindrical body 10 expands to the diameter of the hole after the hollow pipe 1 is pulled out, and accordingly the cylindrical body 10 becomes shorter. The upper end of is 1.5 above the ground.
It becomes M. The operation of the wire 7 during the above construction is as follows: From 0 to V in FIG.
As shown in Figure 4, the hollow tube 1 is pulled out from the skin, but the permeable cylinder 2 is held almost fixed to the ground 1.
Loosen the wire 7 so that it is fixed to the stereotaxic calendar relative to 4.

The construction method of this invention is as described above, and its effects will be explained below.

In state m in Figure 4, in the construction method where sand is supplied to the vicinity of the upper end of the permeable cylinder inside the hollow pipe and the hollow pipe is pulled out all at once above the ground, only sand is discharged from the lower end of the pipe. When constructing sand piles, the water-permeable cylindrical body made of sand inside the hollow tube is also gradually pulled downward and the cylindrical body contracts, so an extra length of the cylindrical body is required.

Also, the length of the hollow pipe must be long enough to accommodate this. (The reason for this is that the hollow formed in the ground by the hollow pipe during extraction is approximately the same as the outside diameter of the hollow pipe, but the diameter of the permeable cylinder before being discharged is similar to that of the sand hollow). Possible factors include the fact that the sand is the same as the inner diameter of the pipe, and the volume of sand changes between when it is supplied into the hollow pipe and when it is discharged from the bottom end of the hollow pipe.) On the other hand, in the method of the present invention, during the steps m and N in FIG. The length of the pipe can be reduced to the minimum length, and the length of the hollow pipe can also be shortened accordingly.

Therefore, the construction cost is reduced, and the safety of the construction machine as a whole is improved because the length of the hollow pipe is shortened.Also, in this invention, the guide pipe 4 is installed not at the upper end of the hollow pipe 1, but in the middle. Since the part where the guide pipe 4 is attached can also be used as a part that penetrates into the ground, there is an effect that the length of the hollow pipe can be further shortened.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view showing an example of a device for carrying out the invention method, Fig. 2 is a partially cutaway side view of the same as above, Fig. 3 is an enlarged longitudinal sectional front view of the same main part, and Fig. 4 is a partially cutaway side view of the same. It is a sectional view according to process. Tortoise: Hollow tube, 4: Guide tube 7: Wire, 10: Permeable cylinder, 14: Soft ground, 15: Sand Pile. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. Insert a permeable cylindrical body of the required length into a suitable position within a hollow pipe for sand pile construction, allow this hollow pipe to penetrate to a specified improvement depth of the ground, and then stop once, and Afterwards, sand was added to bring the sand surface inside the hollow tube near the lower end of the permeable tube, and the hollow tube was pulled out along with the permeable tube, and the sand discharged from the lower end of the hollow tube was used to create a sand pile. was formed, and with the sand still remaining inside the hollow tube, the drawing of the hollow tube was temporarily stopped, and then, sand was introduced into the hollow tube so that the sand surface reached near the upper end of the permeable cylinder. A sand pile construction method characterized by forming a sand pile surrounded by a water-permeable cylinder in a desired area in the ground by later pulling out the hollow pipe while leaving the water-permeable cylinder.