JPH06123115A - Sand drain depositing construction method and its device - Google Patents

Abstract

PURPOSE:To pressedly discharge sand in a casing into the ground to construct a uniform sand pile by piercedly excavating the ground through the casing, and drawing up the casing through the vertical motion and horizontal vibration of an inner lever. CONSTITUTION:The tip of a casing 1 is set at the axial center of a sand pile, and a shoe 12 is pressedly fitted in the lower end of the casing 1. Next the casing 1 is pierced into the ground with its vibration by a vibrohammer 3. In this case, air is jetted from a jetted air supply pipe 11 to facilitate piercing motion for supplying the sand from a sand supply hopper 2 into the casing 1. After the casing 1 attains a fixed depth, the air is supplied into the casing 1 to increase inner pressure, and the vibrohammer 3 is then started again to vibrate the whole casing 1. An air spring 6 and a vibroplot 7 are actuated to draw up the whole device with the vertical motion and horizontal vibration of an inner lever 5, and the sand in the casing 1 is pushed outward. Thus the sand is continuously pressedly discharged to construct the sand pile in the ground.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a sand (gravel, crushed stone, etc.) supplied into the casing by supplying air into the casing after penetrating the casing into the ground to a predetermined depth. Others (including similar ones) are pressurized, and sand is discharged from the lower end of the casing while pulling up the casing to form a sand pile in the ground, and a device therefor.

[0002]

2. Description of the Related Art Conventionally, in this type of construction method, a casing having a sand supplying hopper at its upper portion and a shoe at its lower end which is opened and closed when the casing penetrates, a shutoff valve for sealing the inside of the casing, and Using an air supply means for supplying air into the casing,
After the casing penetrates into the ground and reaches a predetermined depth, the on-off valve is closed, air is supplied into the casing to increase the internal pressure, and while the casing is pulled up, the sand supplied into the casing is replaced with the air. It was designed to be discharged from the lower end of the casing while being pressed by the pressure.

[0003]

As described above, in the conventional method, when the casing is pulled up, the sand in the casing is pressed and discharged only by the air pressure. In this case, there is no problem as long as the sand supplied from the sand supply hopper into the casing is packed with a uniform density along the length of the casing. The sand may be filled in a non-uniform and uneven state such as a lump form or a gap forming a hollow portion. Therefore, when air pressure is applied from above in such a state, the sand Since it is pushed out from the lower end of the casing in a state where it is almost the same as the state where it was filled in the casing, the sand pile formed in the ground is discontinuous, such as constricted in the middle, and it is a very rough sand pile without tightening. There was a chance Also, since it is only due to the air pressure, the amount of momentum air supplied increases, and the sand is overexposed due to excessive pressure, or the sand is not exposed well if the air pressure is too low, thus complicating air control. There was also.

In view of the above problems, the present invention provides a sand drain driving method and an apparatus therefor capable of producing a dense sand pile having a uniform density and a sufficient compaction. It is intended.

[0005]

A sand drain driving method according to the present invention includes a sand supplying hopper 2 and a casing vibrating exciter 3 at the upper portion, and a shoe 12 at the lower end which is closed when the casing is inserted and opened when the casing is pulled up. For sealing the inside of the casing 1 and the inner rod 5 which is inserted and arranged in the casing 1, and which itself vertically moves a predetermined stroke by the vertical driving means 6 and vibrates by the vibrating means 7. Using the open / close valve 9 and the air supply means 10 for supplying air into the casing 1, the inner rod 5 is stopped in the upper limit position, and the casing 1 is vibrated in the ground. After reaching the predetermined depth and closing the on-off valve, air is supplied into the casing 1 to vibrate the casing 1 and move the inner rod 5 up and down. One while vibrating, raising the casing 1, is characterized in that discharging the supplied sand to the casing 1 from its lower end.

Further, the sand drain driving apparatus according to the present invention is provided with a sand supplying hopper 2 at the upper portion and a shoe 12 at the lower end which is closed when the casing 1 is inserted and opened when the casing 1 is pulled up.
And a vibration generator 3 provided at the upper end of the casing 1 for applying vibration to the casing 1.
An inner rod 5 inserted into the casing 1; a vertical drive means 6 for vertically moving the inner rod 5 by a predetermined stroke; a vibrating means 7 for vibrating the inner rod 5; And an air supply means 10 for supplying air into the casing 1.

[0007]

EXAMPLES Examples will be described with reference to the drawings.
FIG. 1 shows a sand drain placing device for carrying out the construction method according to the present invention. In this figure, reference numeral 1 denotes a cylindrical casing, and a casing base 1a at an upper portion thereof has a sand supply hopper 2 on a side wall portion. It is provided. Reference numeral 3 denotes a vibro hammer as a casing vibration exciter that applies vibration to the casing 1, and is installed on an upper portion of a base frame 4 continuous with the casing base portion 1a. 5 is a casing 1
A hollow rod-shaped inner rod that is concentrically inserted and arranged in the inside thereof, the upper end of which is interlockingly connected to an air spring 6 provided as an up-and-down driving means provided on the upper part of the casing base 1a, and the inner rod 5 The upper end is equipped with a vibro flot 7 as a vibrating means. Therefore, the inner rod 5 can be vertically moved by a predetermined stroke by the operation of the air spring 6 and the vibro flot 7 and can vibrate itself. Reference numeral 8 denotes a bifurcated fork integrally connected to the lower end of the inner rod 5.

A sand dropping port 2 is provided in the sand supplying hopper 2.
An opening / closing valve 9 for sealing the inside of the casing 1 at the lower end of a
Further, an air supply nozzle 10 as an air supply means for supplying air into the casing 1 is provided. The on-off valve 9 is normally urged to a closed position by, for example, a spring (not shown), and is opened by the weight of sand when sand is dropped. The air supply nozzle 10 is not shown,
Connected to the air compressor via the air supply pipe,
Air of a required pressure is jetted into the casing 1 when necessary.

A plurality of (for example, two) jet air supply pipes 11 are arranged in the casing 1 along the inner surface thereof, and the upper ends of the jet air supply pipes 11 extend from the upper portion of the casing 1 to the outside. To the air compressor, and the lower end thereof extends to the lower end of the casing 1.

At the lower end of the casing 1, there is provided a shoe 12 which is closed when the casing is inserted and opened when pulled up. As shown in FIG. 2, the shoe 12 has two half-split plates 13 and 13 obtained by splitting a disc into two pieces, which can be freely opened and closed via a support shaft 14 that is transversely provided at the lower end of the casing 1. It is pivotally connected. These half halves 1
When the casings 3 and 13 are inserted into the casing 1, they are press-fitted into the fitting portion 15 formed at the lower end peripheral portion of the casing 1 at the closed position in the horizontal posture as shown by the solid line in FIG.
Even if sand is supplied into the casing 1 while the casing is penetrating, the weight of the sand does not easily open.
In this case, if the ground is relatively hard, both halves 13, 13 will receive an upward load due to the earth pressure of the excavated earth and sand,
Due to this earth pressure, the valve closed posture is maintained more reliably. In addition, reference numeral 16 is a reinforcing frame provided in the casing 1 in a diametrical direction so as to reinforce the support shaft 14.

The inner rod 5 has the air spring 6 as described above.
A predetermined stroke is moved up and down by a predetermined stroke. The upper limit position of the stroke is, for example, the position shown by the solid line of the forked fork 8 shown in FIG. 2, and the lower limit position is the position shown by the phantom line in FIG. Therefore, when the inner rod 5 moves downward from the upper limit position to the lower limit position with the shoe 12 held in the valve closed position shown by the solid line in FIG.
Both half-split plates 13, 13 of the shoe 12 press-fitted to the fitting portion 15 at the lower end are pushed downward by the bifurcated fork 8 to separate from the fitting portion 15 and open the valve. .

Further, as shown in FIG. 2, each half plate 13 of the shoe 12 has a nozzle through hole (notch) at a position facing the tip nozzle 11a of the jet air supply pipe 11 arranged in the casing 1. 17) is provided,
When the shoe 12 is closed, each nozzle 11a penetrates the nozzle through hole 17. Therefore, each nozzle 11a can inject jet air downward from the lower end of the casing 1.

As shown in FIG. 1, the air spring 6 is a lifting member 18 which is vertically slidable along a column 4a of the base frame 4.
Bellows 6a on the upper side and bellows 6b on the lower side across
By alternately supplying air to both bellows 6a and 6b, these bellows 6a and 6b alternately expand and contract, and reciprocate a predetermined stroke up and down, thereby moving the inner rod 5 up and down. It is designed to move. The upper end of the inner rod 5 is connected to the elevating member 18. In addition,
In FIG. 1, reference numeral 19 denotes a protective cylinder body that protects the vibroblot 7 provided on the inner rod 5 inside the casing base portion 1a, and is integrally supported by the casing base portion 1a. An elastic cover 20 having an inner rod 5 slidably inserted therein is attached to the lower end.

Next, a sand drain placing method using the apparatus having the above-mentioned structure will be described.

First, the apparatus is suspended and supported at an appropriate height from the top of a reader (not shown), and the casing 1
Set the tip of the to the sand pile shaft center position to be constructed on the ground. In addition, the shoe 12 taps both half-split plates 13 and 13 from below with a hammer or the like to fit the fitting portion 1 at the lower end of the casing 1.
In the state of being press-fitted in 5, the valve is held at the valve closed position as shown by the solid line in FIG.

Then, start the vibro hammer 3,
The casing 1 is penetrated into the ground while vibrating.
At this time, the tip nozzle 11a of the jet air supply pipe 11
By jetting the jet air below the casing 1, the casing penetration operation can be promoted. During the penetration of the casing, sand is supplied into the casing 1 from the sand supply hopper 2. The air spring 6 and the vibro flot 7 are stopped.

During the penetration of the casing, the shoe 12 has both half plates 13 and 13 pressed into the fitting portion 15 at the lower end of the casing 1, so that the weight of the sand supplied into the casing 1 causes the shoe 12 to move. It will not open easily and will not open even if the ground is extremely soft such as mud. Therefore, sand does not come out of the casing 1 during penetration of the casing, and excavated earth and sand or muddy water does not enter the casing 1.

When the predetermined depth is reached, the vibro hammer 3 is temporarily stopped, the on-off valve 9 is closed (in this embodiment, it is always closed except when sand is supplied), and air is supplied from the air supply nozzle 10 into the casing 1. To increase the internal pressure. Also,
The supply of air to the jet air supply pipe 11 is stopped.
After that, restart the vibro hammer 3 and restart the casing 1.
The whole body is vibrated and the air spring 6 is activated to move the inner rod 5 up and down by a predetermined stroke.
Is started to horizontally vibrate the inner rod 5, and the entire apparatus is pulled up, whereby the sand in the casing 1 is pushed out from the lower end thereof to start forming sand piles in the ground.
By the first downward movement of the inner rod 5, the two half plates 13, 13 of the shoe 12 are pushed open by the bifurcated fork 8 at the lower end of the inner rod 5 to open the valve.

During the raising of the casing, the sand in the casing 1 is sufficiently oscillated by the vibrating action of the casing 1 itself by the vibro hammer 3 and the vertical movement and horizontal vibrating action of the inner rod 5 by the air spring 6 and the vibro flot 7. It is compacted into a uniform density state without unevenness. Therefore, when air pressure is applied from above in such a state, the sand is discharged from the lower end of the casing 1 in a continuously compacted state, and the compact sand is compacted evenly and sufficiently in the ground. Create a stake. If the sand is insufficient during the formation of the sand pile, the above-described formation work may be stopped once, the sand may be replenished, and then the work may be restarted to continue the formation.

When the sand pile is formed up to the surface of the ground, the casing 1 is completely pulled up, the vibro hammer 3, the air spring 6 and the vibro flot 7 are operated, and the air is supplied from the air supply nozzle 10. Stop and finish the construction work.

In this embodiment, the air spring 6 is used as the vertical drive means for the inner rod 5, but instead of the air spring 6,
An air cylinder or hydraulic cylinder may be used. Also,
As a vibrating means for the inner rod 5, a suitable vibrator other than the vibro flot 7 can be used, and as a vibrating device for casing vibration, a suitable vibrator other than the vibro hammer 3 can be used.

[0022]

According to the construction method of the present invention, when the casing is being pulled up, the sand inside the casing vibrates the casing as a whole by the vibration generator and the vertical movement of the inner rod by the vertical drive means and the vibration means. It is compacted sufficiently by the vibration action and has a uniform density state without unevenness. Therefore,
By applying air pressure from above the sand in such a state,
The sand in the casing is continuously discharged from the lower end of the casing in a state of being compacted, whereby it is possible to form a compact and strong sand pile that is sufficiently compacted and solidified in the ground. Further, according to this construction method, the air supply amount can be small, and the air can be easily controlled.

Further, the shoe is closed so as not to be opened by the weight of sand supplied into the casing when the casing penetrates, and is pushed open by the lower end portion of the inner rod when the casing is pulled up. At times, it is possible to prevent excavated sediment and muddy water from entering the casing.

When jetting jet air to the lower side of the casing from the tip nozzle of the jet air supply pipe arranged inside the casing at the time of penetration of the casing, the jetting pressure of the jet air accelerates the ground excavation action. The ground penetration speed of the casing can be increased, and the penetration time can be shortened.

Further, in the apparatus of the present invention, a bifurcated fork is continuously provided at the lower end of the inner rod, and the shoe can be freely opened and closed through a support shaft extending in the diameter direction of the casing at the lower end of the casing. Formed by two half-ply plates pivotally attached,
It is configured so that it will not be opened by the weight of the sand supplied into the casing, it will be press-fitted into the fitting part provided at the lower peripheral edge of the casing, and it will be pushed open by the downward movement of the fork accompanying the downward movement of the inner rod. As a result, when the casing penetrates, even if the ground is extremely soft ground such as muddy water, the shoe can be reliably held in the closed state, and when the casing is pulled up, the bifurcated fork is used without using a special opening drive means. The shoe can be opened easily and easily.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view showing a sand drain driving device according to the present invention.

FIG. 2 is an enlarged detailed cross-sectional view of a tip portion of a casing.

[Explanation of symbols]

1 Casing 2 Sand Supply Hopper 3 Vibro Hammer (Casing Vibration Oscillator) 5 Inner Rod 6 Air Spring (Up / Down Drive Means) 7 Vibro Flot (Vibration Means) 8 Bifurcated Fork 9 Open / Close Valve 10 Air Supply Nozzle ( Air supply means) 11 Jet air supply pipe 12 Shoe 13 Half plate 14 Spindle 15 Fitting part

Claims (6)

[Claims] 1. A casing having an upper part provided with a sand hopper and a vibrating device for vibrating the casing, and a lower end provided with a shoe having a shoe which is closed when the casing penetrates and opened when the casing is pulled up. Using an inner rod that is vertically moved by a vertical drive means for a predetermined stroke and vibrated by a vibrating means, an on-off valve for sealing the inside of the casing, and an air supply means for supplying air into the casing, With the inner rod stopped at the upper limit position, the casing penetrates into the ground while vibrating the casing, and after reaching a predetermined depth, the on-off valve is closed and air is supplied into the casing to close the casing. While vibrating and vertically moving and vibrating the inner rod, the casing is pulled up, and the sand supplied into the casing is discharged from the lower end thereof. Sand drain striking 設工 method in which it characterized in that. 2. The shoe is closed so as not to be opened by the weight of sand supplied into the casing when the casing penetrates, and is pushed open by the lower end portion of the inner rod when the casing is pulled up. The sand drain driving method according to claim 1. 3. The sand drain method according to claim 1, wherein when the casing penetrates, jet air is jetted below the casing from a tip nozzle of a jet air supply pipe provided in the casing. 4. A casing having a sand hopper at the upper part and a shoe at the lower end, which is closed at the time of penetration of the casing and opened at the time of pulling up, and a vibrating device provided at the upper end of the casing for vibrating the casing. An inner rod inserted into the casing, a vertical drive means for vertically moving the inner rod by a predetermined stroke, a vibrating means for vibrating the inner rod, an on-off valve for sealing the inside of the casing, and the casing. A sand drain placing device comprising air supply means for supplying air into the inside. 5. A bifurcated fork is connected to the lower end of the inner rod, and the shoe is pivotally attached to the lower end of the casing via a support shaft extending in the diameter direction of the casing so as to be openable and closable. It is formed by two half-divided plates, and it is press-fitted into a fitting portion provided on the lower end peripheral portion of the casing so as not to be opened by the weight of the sand supplied into the casing when the casing penetrates, and when the casing is pulled up, The sand drain placing device according to claim 4, wherein the device is configured to be pushed open by a fork at a lower end of the rod. 6. A jet air supply pipe is provided in the casing, and jet air is jetted downward from a lower end of the casing from a nozzle of the supply pipe when the casing penetrates. The sand drain placing device described in.