JPH11200357A - Improvement method of soft ground and drilling device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a soft ground by protruding sideway a part of a bit side face while rotating a drilling bit to excavate the side and forming a sand pile having protruded parts at the side. SOLUTION: A drilling device is constituted of a drilling rod equipped with a bit at the tip thereof, a rotary driving part, a winching part, and a winch. A bit with a U-shaped section is detachably fitted to the tip of the drilling rod and a part of the side face of the bit is protruded sideway by the piston of a hydraulic cylinder equipped in the drilling rod. The drilling rod is driven into a soft ground A and when it reaches a specified depth, the hydraulic cylinder is actuated by the hydraulic control from above the ground to protrude a part of the side face of the bit and excavate the side, and then, sand is charged. Projections 12 are formed at every specified distance. Finally, the drilling rod is drawn up while charging sand to install a sand pile. In this way, a sand quantity required for the preparation can be greatly reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for improving a soft ground by discharging water and air contained in the soft ground without replacing the soil, thereby improving the soft ground and a perforation used in the method. Related to the device. More specifically, the present invention relates to an improved method of soft ground capable of greatly reducing the amount of sand required for forming a sand pile installed in soft ground, and a perforation apparatus used in the method.

[0002]

2. Description of the Related Art Conventionally, as an improvement method for soft ground,
The sand drain method is one of the many methods that have been implemented. In this sand drain method, a number of sand piles (artificial sand columns) are installed vertically at appropriate intervals in soft ground, and water in the ground is extracted through these sand piles to consolidate and strengthen the ground. This is a method to promote the increase and improve the ground.

[0003]

However, in this sand drain method, a sand pile having a diameter of 0.4 m to 0.6 m and a depth of 5 m to 10 m is provided over the entire area of the improvement area. Dozens had to be installed, and the amount of sand used for this was enormous.

[0004] The present invention has been made in view of such circumstances, and an improved method of soft ground capable of greatly reducing the amount of sand required for forming a sand pile installed in soft ground, and an improvement method thereof. It is an object to provide a perforating device for use in the method.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a plurality of sand piles are installed at an appropriate interval in a soft ground to a required depth, and the soft ground is passed through the sand pile. In the method of improving soft ground for discharging water therein, the sand pile is provided with a protruding portion that projects laterally at a predetermined interval in a depth direction of the soft ground. The outline of the improved method was adopted.

According to a second aspect of the present invention, the drilling rod is driven into a soft ground to a predetermined depth while rotating the drilling rod, and then, while rotating the drilling rod, a part of the bit side surface of the tip end of the drilling rod is sided. The excavation is performed to the required depth of the soft ground by repeatedly performing an operation of excavating the side and excavating the side, and filling the excavated portion with sand, at predetermined intervals in the depth direction of the soft ground. The gist of the present invention is a method of improving soft ground characterized by installing a sand pile having a protruding portion that protrudes from the ground.

The gist of the invention according to claim 3 is to provide an improved method of soft ground characterized by carrying out an embankment with sand on an area where a sand pile of soft ground is installed.

According to a fourth aspect of the present invention, a water-permeable material connected to a vacuum pump is disposed horizontally in the upper embankment,
The gist of the present invention is a method of improving soft ground, wherein the upper embankment and the water-permeable material are covered with an airtight sheet, and the vacuum pump is operated to bring the upper surface of the ground into a negative pressure state.

The gist of the invention according to claim 5 is to provide an improved method for soft ground characterized by further embankment on an airtight sheet.

According to a sixth aspect of the present invention, there is provided a drilling device used for installing a plurality of sand piles at a suitable interval in a soft ground to a required depth. It has a rotation drive unit that rotates the rod, and a winding unit that winds up the perforation rod, and a part of the bit side surface of the tip of the perforation rod projects sideways by a cylinder provided in the perforation rod. The gist of the present invention is a perforation apparatus characterized in that:

According to a seventh aspect of the present invention, a drilling rod is provided with a muddy pipe for guiding muddy water, a slime discharge pipe for discharging muddy water slime, and a fluid pipe for guiding cylinder working fluid. The gist of the present invention is that a drilling device is provided with a supply port for supplying muddy water from the muddy water pipe to a hole wall and a receiving port for receiving and discharging muddy water slime.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for improving soft ground according to the present invention and a drilling device used in the method will be described in more detail with reference to an embodiment shown in the drawings. The following is a description of a method for improving soft ground of the present invention (hereinafter simply referred to as an improvement method), and a drilling device will be described in detail in the description of the improvement method. This improved construction method is an improvement of the sand train construction method in which a plurality of sand piles are installed at appropriate intervals in a soft ground to a required depth, and water in the soft ground is discharged through the sand piles.

That is, as shown in FIG. 1, the improved construction method is characterized in that a sand pile 11 is provided with a protruding portion 12 protruding laterally at a predetermined interval in the depth direction of the soft ground A. It is. Thus, the projecting portion 1 on the side
As shown in FIG. 5, the drainage capacity of the sandpile 11 provided with 2 has substantially the same drainage capacity as the conventional sandpile 1 provided with the same diameter as the protruding portion 12 of FIG.

For this reason, the diameter of the sand pile 11 itself may be small, and the amount of sand used can be greatly reduced. In addition, when the diameter of the sand pile 11 itself is set to 0.4 m to 0.6 m as in the related art, the drainage capacity is increased by the provision of the protruding portion 12 on the side of the sand pile 11.

As described above, the projecting portion 12 projecting sideways
Various methods are conceivable as a method of installing the sand pile 11 provided with at predetermined intervals in the depth direction of the soft ground A, and a preferable installation example using the drilling device of the present invention will be described below. .

As shown in FIGS. 2 to 4, a piercing device 20 according to the present invention comprises a piercing rod 21 having a bit 22 at a tip end.
A rotation driving unit (not shown) for rotating the perforation rod 21; and a winding unit for winding the perforation rod 21 (a wire or chain 29 fixed to the perforation rod 21).
And a winding device (not shown) for winding the same.

A bit 22 having a U-shaped cross section is detachably attached to the tip of the piercing rod 21. A part 22 a of the side surface of the bit 22 is connected to a piston 24 of a hydraulic cylinder 23 provided in the piercing rod 21,
It projects to the side by hydraulic pressure. Also,
A muddy pipe 25 for guiding muddy water and a slime discharge pipe 26 for discharging muddy slime are provided in the perforated rod 21, and a muddy water supply port 27 and a slime receiving port 28 provided on the side surface of the perforated rod 21 are provided. The mud from the mud pipe 25 is supplied to the hole wall, and mud slime from the hole wall is received.

An oil pipe 31 for guiding oil pressure is provided in the drilling rod 21. The hydraulic cylinder 23 is operated by hydraulic control from the ground, and the bit connected to the piston 24 of the hydraulic cylinder 23 is provided. A part 22a of the side surface of 22 is moved in and out of the side.

In the embodiment shown in the drawings, the piercing rod 2
1 is covered by a casing 30 having a diameter larger than that of the perforated rod 21, but it is not always necessary to provide the casing.

Next, the sand pile 11 is provided at predetermined intervals in the depth direction of the soft ground A using the above-described drilling device 20.
The step of forming is described.

First, the piercing rod 21 of the piercing device 20 is driven into the soft ground A to a predetermined depth. The driving of the piercing rod 21 depends on the weight of the piercing rod 21 itself and the rotational force of a rotation drive device (not shown). In this case, the wire or the chain 29 fixed to the piercing rod 21 is unwound according to the piercing state of the piercing rod 21.

Next, as shown in FIG. 1, projecting portions 12 are provided on the side of the sand pile 11 at predetermined intervals in the depth direction of the soft ground A. The protruding part 12 is shown in FIGS.
As shown in FIG. 4, when the piercing rod 21 reaches a predetermined depth, the hydraulic cylinder 23 is operated by hydraulic control from the ground while rotating the piercing rod 21 and connected to the piston 24 of the hydraulic cylinder 23. A part 22a of the side surface of the bit 22 is protruded to the side to excavate the side. Thereafter, the excavated portion is filled with sand, so that it becomes the protruding portion 12.

The above-described operation is repeated to a required depth of the soft ground, and finally, the hole or the hole 29 of the piercing rod 21 is filled with sand, and the piercing rod 21 is wound up by pulling up the wire or the chain 29 to pull up. The sand pile 11 shown in FIG. 1 is installed.

The number and spacing of the sand piles 11, the spacing of the protruding portions 12, and the protruding width are arbitrary, and may be appropriately determined in consideration of the geology and size of the soft ground A, the depth of the ground, and the like. .

As shown in FIG. 4, the protrusion width of the part 22a on the side surface of the bit 22 is determined by changing the geology and size of the soft ground A,
It can be appropriately changed in consideration of the depth of the ground and the like.

In this manner, the soft ground A in which a plurality of the sand piles 11 provided with the protruding portions 12 at predetermined intervals in the depth direction of the soft ground A are provided, for example, It is also possible to carry out the embankment 33 with sand in the installation area. In this case, more efficient consolidation drainage can be performed by the top embankment made of sand.

Further, as shown in FIG. 1, a water-permeable material 34 connected to a vacuum pump 35 horizontally in the upper embankment 33.
And the embankment 33 and the water passing material 3
4 can be covered with an airtight sheet 36 and the vacuum pump 35 can be operated to bring the upper surface of the ground A into a negative pressure state.

In this case, a pressure difference is generated between the soil A and the pore water pressure, and the pressure difference causes water and air in the ground to be sucked out to the surface of the ground A through the sand pile 11. The water and air sucked into the sand layer 33 on the ground surface are discharged (to the drainage tank 37) through the horizontally arranged water-permeable material 36.

The embankment 38 is further placed on the airtight sheet 36.
Can also be performed. In this case, a load due to the embankment 38 is applied to the ground A, and more efficient consolidation dewatering is performed.

[0030]

According to the method for improving soft ground of the present invention, since the sand pile is provided with a protruding portion projecting laterally at a predetermined interval in the depth direction of the soft ground, The amount of sand required for the construction of the sand pile installed in the can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of an improvement method for soft ground according to the present invention.

FIG. 2 is a cross-sectional view showing a state in which a piercing rod of a piercing device is driven into a soft ground to a predetermined depth, and a part of a bit at a tip end of the rod is laterally protruded to provide a protruding portion.

FIG. 3 is an enlarged sectional view showing a perforation device of the present invention.

FIG. 4 is an enlarged sectional view taken along line AA of FIG. 3;

FIG. 5 is a cross-sectional view showing a sand pile installed by a conventional soft ground improvement method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Sand pile 12 ... Projection part 20 ... Drilling device 21 ... Drilling rod 22 ... Bit

Claims (7)

[Claims] The method according to claim 1, wherein a plurality of sand piles are installed at appropriate intervals in the soft ground to a required depth, and water in the soft ground is discharged through the sand piles. A soft ground improvement method, wherein a protruding portion is provided at a predetermined interval in the depth direction of the soft ground so as to protrude laterally. 2. Driving the drilling rod into the soft ground to a predetermined depth while rotating the drilling rod, and then, while rotating the drilling rod, projecting a part of the bit side surface of the tip of the drilling rod to the side. By repeatedly performing operations such as excavating the side and filling the excavated portion with sand, to a required depth of the soft ground, a protruding portion projecting laterally at a predetermined interval in the depth direction of the soft ground 2. The method for improving soft ground according to claim 1, wherein a sandpile provided with is provided. 3. The method for improving soft ground according to claim 1, wherein an embankment of sand is applied to an area of the soft ground where a sand pile is installed. 4. A water-permeable material connected horizontally to a vacuum pump is arranged in the upper embankment, and the upper embankment and the water-permeable material are covered with an airtight sheet, and the vacuum pump is operated to thereby provide an upper surface of the ground. 4. The method for improving soft ground according to claim 3, wherein the pressure is set at a negative pressure. 5. The method for improving soft ground according to claim 4, wherein embankment is further performed on the airtight sheet. 6. A piercing device used for installing a plurality of sand piles at a proper interval in a soft ground to a required depth, comprising: a piercing rod having a bit at a tip portion; and a rotary drive for rotating the piercing rod. And a lifting part for raising and lowering the piercing rod in the soft ground, wherein a part of the bit side surface of the tip of the piercing rod projects sideways by a cylinder provided in the piercing rod. A perforation device characterized in that: 7. A drilling pipe for guiding muddy water, a slime discharging pipe for discharging muddy water slime, and a fluid pipe for guiding cylinder working fluid are provided on the drilling rod. The drilling device according to claim 6, further comprising a supply port for supplying muddy water to the hole wall and a receiving port for receiving and discharging muddy water slime.