JPH0718653A - Executing method for liquefaction preventing drain pile of sand soil property/ground and drain pile - Google Patents

Abstract

PURPOSE:To prevent the liquefaction of the sand ground by storing a hollow cylindrical drain material in a casing auger drilling a well hole in the sand ground, drilling the hole, leaving a tip bit as an anchor after drilling, and burying the drain material. CONSTITUTION:A cylindrical casing auger 6 is rotatably fitted to a rotary drive device 5, and a concrete tip bit 7 is removably fitted to the tip of the casing auger 6. A drain material is inserted and stored inside the cylindrical casing auger 6, and the tip bit 7 is coupled with the lower end section of the casing auger 6 so that the rotation in only one direction can be transferred. 1 When the drilling work reaches the planned depth, the casing auger 6 is rotated in the opposite direction, then the coupling state between the casing auger 6 and the tip bit 7 is released, and the casing auger 6 is retreated. The tip bit 7 bites into the sand ground 1, and the drain material fitted to the tip bit 7 is released from the casing 6 in sequence and left in a drilled hole as it is.

Description

Detailed Description of the Invention

[0001]

[Field of Industrial Application] The present invention relates to a liquid generated by an earthquake in artificially formed land such as a landfill or an embankment land, and a sand ground with high groundwater level and soft ground such as land near the sea or river. The present invention relates to a method for burying a drain pile that is buried in a columnar shape in the ground in order to prevent deterioration and a drain pile therefor.

[0002]

Liquefaction in this type of sand ground is a phenomenon in which a soft sand ground becomes unstable like a liquid due to a sudden rise in groundwater pressure due to an earthquake. When lifelines such as roads are built,
These will collapse or collapse. As a conventional method of preventing such liquefaction, a drain pipe method and a crushed stone drain method are known.

In the above-mentioned drain pipe construction method, for example, a plastic pipe having a diameter of 10 cm and a length of 9 m, in which a large number of holes are formed, is used. The drain pipe wound with the filter material is housed in a predetermined casing auger, and the casing auger is configured such that the bit at the tip thereof can be opened and closed, and the casing auger has a predetermined depth in the target sand ground. Excavating a hole in the hole, open the bit at the tip and leave the drain pipe in the casing auger in the hole to pull out the casing auger.
In this way, it is a method of burying a plurality of drain pipes in the vertical direction at a predetermined interval.

The crushed stone draining method uses a hollow pipe auger whose tip can be freely opened and closed, and a hole having a diameter of 50 cm and a depth of about 20 m is excavated in the target sand ground, and the tip is opened to open the hollow pipe auger. The hollow pipe auger is pulled out while the crushed stones are being charged into the crushed stones, and the crushed stones that have been injected are solidified to form crushed stone columns. This is a method of forming a plurality of these crushed stone columns at predetermined intervals.

The drain pipe and the crushed stone column in these conventional examples suppress a liquefaction phenomenon by digging a kind of well in the sand ground and letting the groundwater pressure that rises when an earthquake occurs from the well to the surface of the ground. is there.

[0006]

In the construction of the above drain pipe construction method, the tip of the casing auger is opened so that the drain pipe inside is left in the ground, but if the tip is not opened and closed sufficiently, the casing auger is not opened. There is a problem in construction that the drain pipe cannot be buried at the planned depth because it is lifted up together when the pipe is pulled out.

After the drain pipe is buried, even if there is a comparatively weak seismic intensity of about 3, the drain pipe is lifted by the push-up action due to the increase in groundwater pressure, and the drain pipe once lifted I can't sank it in its original position, and in some places I have to get in the way to remove the protruding parts,
In addition, after that, in the event of an emergency (when an earthquake with seismic intensity of 5 to 6 occurs), the function cannot be fulfilled.

In the above-mentioned crushed stone drain method, crushed stones are put into a well hole excavated through a hollow pipe auger,
Since the work of tamping is done in a fumbling condition that is completely invisible from the outside, the workability of the construction work is poor, and when the groundwater level rises due to rainfall or an earthquake, sand is crushed inside the crushed stones. There is a problem that it gradually enters and gradually fills the gap, and when it comes to an emergency, its function cannot be fully fulfilled.

Therefore, the conventional example has a problem to be solved in workability of construction and maintenance of well shape and function for a long period of time.

[0010]

As a concrete means for solving the above-mentioned problems of the conventional example, the present invention is detachable from the tip of a casing auger for drilling a well hole of a predetermined size and a predetermined depth in a sand ground. A tip bit is attached, a hollow cylindrical drainage material is connected to the tip bit, the drainage material is housed in a casing auger for drilling, and the drainage material is removed while leaving the tip bit as an anchor after drilling. Method for constructing a drain pile for preventing liquefaction of sand ground characterized by being buried, and a tip bit detachably attached to the tip of a casing auger for drilling a well hole of a predetermined size and a predetermined depth in the sand ground To provide a drain pile for preventing liquefaction of sand ground, characterized in that a hollow cylindrical drainage material is connected to the tip bit. The drain stake is attached by engaging with the casing auger so that the rotation from one direction is transmitted, and the connection between the tip bit and the drainage material is performed by a pipe having many holes in the peripheral surface. Is.

[0011]

A hollow cylindrical drainage material is housed in a casing auger for drilling a well hole, and the tip bit is detachably engaged and attached so that only rotation in one direction can be transmitted. By connecting the drainage material and burying the tip bit as an anchor for the drainage material after drilling, the drainage material can be easily buried and the drainage material does not float up and remains stable for a long time. Can be maintained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in more detail with reference to the illustrated embodiment. In FIG. 1, reference numeral 1 is a sand ground to be liquefied, and the sand ground 1 has a boring device such as an auger. Is used to drill a well hole having a predetermined size (100 to 200 mm) and a depth (3 to 15 m), and a drain pile made of a cylindrical drainage material is buried or constructed in the well hole.

In this case, as a device for drilling a well hole, for example, a drilling device 2 in which a machine-installed rubber caterpillar excavator is improved is used, and a columnar slide base 4 is attached to the tip of an arm 3 of the drill. The rotation drive device 5 is slidably attached to the base.

The rotary drive device 5 can be operated to rotate and slide at the driver's seat of the drilling device 2, and a cylindrical casing auger 6 is attached to the rotary drive device 5 so as to be rotationally driven. A tip bit 7 made of concrete is detachably attached to the tip of the casing auger 6.

As shown in FIG. 2, the tip bit 7 has a fin 8 for an auger integrally formed on the peripheral surface thereof, and a projection 9 for connection with the casing auger 6 is formed. A locking portion 10 for locking rotation in one direction (clockwise) is provided on the outer peripheral surface of the connecting convex portion 9, and a projection 11 for mounting a cylindrical drainage material is further integrated on the upper surface of the connecting convex portion 9. Is formed in the same way.

The engaging portion 10 is composed of at least one sloping portion 1a inclined in one direction and a cliff 1b,
In the illustrated embodiment, two inclined portions 1a and two cliffs 1b are formed in symmetrical positions on the outer peripheral surface of the connecting convex portion 9. The tip bit 7 may be mixed with garnet in order to increase its hardness.

The cylindrical drainage material 12 attached to the tip bit 7 is a resin string, that is, a linear polypropylene of about 2 mm is heated and melted, extruded from a nozzle, and laminated in a curled state in order to form a mutual filament. It is composed of a core material 13 (generally available on the market: Hetimaron-Shinko Nylon Co., Ltd.) in which a contact is welded and molded into a hollow cylindrical shape, and a filter material 14 which is wound around and fixed to the outer peripheral surface thereof.

The drainage material 12 has a core hole 15 of a predetermined size formed in the central portion along the length thereof, is substantially flexible and has a high pressure resistance, and the surface porosity thereof is 95-. The porosity is 97% and the porosity is 80 to 95%, and the porosity is 80% when the load is about 10 t / m 2.

The filter material 14 may be made of any suitable non-woven fabric or non-woven fabric, and for example, non-woven fabric of long fibers made of polypropylene is most preferably used.

The drainage material 12 as described above is attached to the tip bit 7 by a resin pipe 16 penetrating the core hole 15 of the core material 13 and having substantially the same size as the core material 13.

In this case, the pipe 16 has a large number of holes 1 on its peripheral surface.
7 is used, the lower end portion of the pipe 16 is fitted to the connecting convex portion 9 of the tip bit 7 and fixed by an appropriate fixing means such as an adhesive means, and the lid member 18 is attached to the upper end portion. By attaching, the drainage material 12 is sandwiched and fixed by the tip bit 7 and the lid material 18.

The lid member 18 used is made of resin and has a cylindrical convex portion 19 projectingly formed at the center of the lower surface thereof, and a large number of holes 20 provided over the entire surface of the lid member. The cylindrical convex portion 19 is attached to the upper end portion of the pipe 16 and fixed by an adhesive means or the like.
It is a so-called drain stake.

The drain pile thus constructed, that is, the drainage material 12, is inserted and housed inside the cylindrical casing auger 6, and the tip bit 7 is fitted to the lower end portion of the casing auger 6 so that it can rotate only in one direction. Are engaged for transmission.

That is, on the inner peripheral surface of the lower end of the casing auger 6, there is provided an engaging portion (not shown) composed of an inclined portion corresponding to the engaging portion 10 of the tip bit 7 and a cliff, and these engaging portions. By attaching the tip bit 7 to the tip portion of the casing auger 10 so that the engaging portion 10 and the engaging portion are aligned with each other, the tip bit 7 can be rotated only in one direction, for example, clockwise.
Is configured to be transmitted to.

After the tip bit 7 and the drainage material 12 are set in the casing auger 6 in this way, the drilling device 2 is operated and the arm 3 thereof is operated as shown in FIGS.
Is driven to set the slide base 4 and the casing auger to a predetermined position in an upright state, and the rotation driving device 5 is driven to rotate the casing auger 6 for drilling.

In the case of this drilling, the casing auger 6 rotates in one direction, that is, the clockwise direction, and the tip bit 7 also rotates in accordance with the rotation, and advances in sequence in the sand ground 1 to form a hole having a predetermined depth. Is drilled. The depth of this hole is determined in advance by investigating the condition of the sand ground 1, a casing auger having a length corresponding thereto is used, and a drainage material 12 corresponding to the length is stored.

When the drilling work reaches the planned depth,
When the drive device 5 is driven to rotate the casing auger 6 in the reverse direction, the engagement state between the engagement portion of the casing auger 6 and the locking portion 10 of the tip bit 7 is dissociated, and as shown in FIG.
The rotation is not transmitted to the tip bit 7, and the casing auger 6 is sequentially retracted.

At this time, the tip bit 7 is in a state of biting into the sand ground 1 by the fin 8 and is not dragged even if the casing auger 6 moves backward. Therefore, the tip bit 7 serves as an anchor, and the drainage material 12 attached to the tip bit 7 sequentially comes out of the casing auger 6 and remains as it is in the drilled hole.

In order to prevent the drainage material 12 from being forcibly pulled out or stretched by frictional engagement between the inner peripheral surface of the casing auger 6 and the drainage material 12 in the pulling operation of the casing auger 6, As shown in FIG. 5, the weight W may be placed in the casing auger 6 and above the drainage material 12, and the casing auger 6 may be pulled out by pressing the weight W.

In this way, holes are sequentially drilled at predetermined intervals, and the drainage material 12 is left together with the tip bit 7 in each drilled well hole. As a result, the drainage material 12 is used as a drain pile in the sand ground 1. Can be buried. The drilling and embedding intervals may be about 0.5 to 5 m depending on the condition of the sand ground.

Then, the drainage material 12 inserted into the well hole 12
The upper end portion of may be projected several centimeters as it is, or may be buried slightly lower than the surface of the earth, and a crushed stone layer having a predetermined thickness may be formed on the upper portion thereof to form a substantial lid.

In the above description, the well hole is drilled substantially vertically. However, if the slide base 4 is installed while being tilted at an appropriate angle, a hole corresponding to the tilt angle is drilled. Along with the inclination angle, drainage material 12
Can be buried.

Incidentally, in the sand ground 1, there is a case where a hardly permeable layer composed of clay, silt or the like exists in the middle. The water-impermeable layer has a very fine particle size, and the fine particles may be sequentially melted and adhered to the filter material 14, and may be sequentially deposited in the drainage material 12 to cause a substantial clogging phenomenon.

In such a case, in order to prevent the fine particles from leaching out, a material that does not allow water to pass through the outer peripheral surface of the filter material 14 at a portion corresponding to the water-impermeable layer in advance, such as vinyl tape. May be wound to form the non-water-permeable portion.

In any case, if the tip bit 7 is left as a kind of anchor material at the time of drilling the well hole with the casing auger 6, in any case,
Drainage material 12 can be prevented from floating and drainage material 1
The burying work of 2 can be easily performed.

[0036]

As described above, the method of constructing a drain pile for liquefaction prevention of sand ground according to the present invention is a tip of a casing auger for drilling a well hole of a predetermined size and a predetermined depth in the sand ground. Attaching a tip bit to the tip bit in a detachable manner, connecting a hollow cylindrical drainage material to the tip bit, storing the drainage material in a casing auger for drilling, and leaving the tip bit as an anchor after the drilling. By burying the drainage material, the underground burial or construction work of the drain pile can be remarkably facilitated, and the drain pile can be installed in an appropriate state at a predetermined place.

Further, the drain pile for liquefaction prevention of the sand ground is a cement containing a garnet tip bit that is detachably attached to the tip of a casing auger for drilling a well hole of a predetermined size and a predetermined depth in the sand ground. The drainage material in the shape of a hollow cylinder is connected to the tip bit, so that drilling work can be performed quickly, and the floating phenomenon is eliminated by leaving the tip bit as an anchor, and in the long term. It has an excellent effect that the buried state can be maintained stably over a long period of time, whereby liquefaction of the sand ground can be prevented for a long period of time.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing a method of constructing a drain pile for preventing liquefaction of sand ground according to the present invention.

FIG. 2 is a perspective view showing the drainage pile for preventing liquefaction separated and partially omitted.

FIG. 3 is a side view showing only a main part for explaining a construction state of the drainage pile for preventing liquefaction.

FIG. 4 is a side view showing only a main part for explaining a construction situation similar to that of FIG.

FIG. 5 is an explanatory view showing only a main part for explaining a construction state of the drainage pile for preventing liquefaction.

[Explanation of symbols]

 1 Sand Ground 2 Drilling Device 3 Arm 4 Slide Base 5 Rotation Drive Device 6 Casing Auger 7 Tip Bit 8 Fin 9 Connecting Convex Part 10 Locking Part 10a Inclined Part 10b Cliff Part 11 Protrusion 12 Drainage Material 13 Core Material 14 Filter Material 15 Core hole 16 Resin pipe 17, 20 Many holes 18 Lid material 19 Cylindrical convex part

[Procedure amendment]

[Submission date] June 30, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

[Title of Invention] Construction method of drain pile for preventing soil liquefaction and ground liquefaction and its drain pile

[Claims]

Detailed Description of the Invention

[0001]

[Field of Industrial Application] The present invention relates to artificially formed land such as a landfill or an embankment site, as well as to the ground and ground of soft sand with a high groundwater level in land near the sea or river.
The present invention relates to a method for burying a drain pile that is buried in a pillar shape in the ground to prevent liquefaction caused by an earthquake, and the drain pile.

[0002]

2. Description of the Related Art The liquefaction of sand of this kind in the geology and ground is a phenomenon in which the geology and ground of soft sand becomes unstable like a liquid due to a sudden rise in groundwater pressure due to an earthquake. When a building such as a house or a lifeline such as a road is constructed, these collapse or collapse. As a conventional method of preventing such liquefaction, a drain pipe method and a crushed stone drain method are known.

In the above-mentioned drain pipe construction method, for example, a plastic pipe having a diameter of 10 cm and a length of 9 m, in which a large number of holes are formed, is used. The drain pipe wound with the filter material is housed in a predetermined casing auger, and the casing auger is configured such that the bit at the tip thereof can be opened and closed. A hole with a predetermined depth is drilled, the bit at the tip is opened, and the drain pipe in the casing auger is left in the hole to pull out the casing auger. This is the method of burying the drain pipe.

In the above-mentioned crushed stone drain method, a hollow tube auger whose tip is openable and closable is used, a hole having a diameter of 50 cm and a depth of about 20 m is excavated in the target sand geology / ground, and the tip is opened. The hollow pipe auger is pulled out while the crushed stones are put into the empty pipe auger, and the crushed stones that are put into the hollow pipe auger are compacted to form crushed stone columns. This is a method of forming a plurality of crushed stone columns at predetermined intervals.

The drain pipe and the crushed stone column in these conventional examples both suppress a liquefaction phenomenon by digging a kind of well in the sand geology / ground and letting the groundwater pressure that rises at the time of the earthquake occur from the well to the surface of the ground. To do.

[0006]

In the construction of the above drain pipe construction method, the tip of the casing auger is opened so that the drain pipe inside is left in the ground, but if the tip is not opened and closed sufficiently, the casing auger is not opened. There is a problem in construction that the drain pipe cannot be buried at the planned depth because it is lifted up together when the pipe is pulled out.

Further, after the drain pipe is buried, even if there is a comparatively weak earthquake, the drain pipe may be lifted up due to the push-up action due to the rise of groundwater pressure, and the drain pipe once lifted will be in the original position. It cannot be submerged in the area, and depending on the location, it has to be removed and the protruding part must be removed, and after that, in the event of an emergency (when an earthquake of 5 or more occurs in the JMA seismic intensity group) its function Cannot be achieved.

In the above-mentioned crushed stone drain method, crushed stones are put into a well hole excavated through a hollow pipe auger,
Since the work of tamping is done in a fumbling condition that is completely invisible from the outside, the workability of the construction work is poor, and when the groundwater level rises due to rainfall or an earthquake, sand is crushed inside the crushed stones. There is a problem that it gradually enters and gradually fills the gap, and when it comes to an emergency, its function cannot be fully fulfilled.

Therefore, the conventional example has a problem to be solved in workability of construction and maintenance of well shape and function for a long period of time.

[0010]

As a concrete means for solving the above-mentioned problems of the prior art, the present invention is directed to the tip of a casing auger for drilling a well hole of a predetermined size and a predetermined depth in the geology and ground of sand. A tip bit is detachably attached, a hollow cylindrical drainage material is connected to the tip bit, the drainage material is housed in a casing auger for drilling, and after the drilling, the tip bit is left as an anchor. Geology of sand, which is characterized by burying drainage material, construction method of drain pile for liquefaction prevention of ground, and geology of sand, of casing auger drilling well hole of specified size and depth in ground Drain for preventing soil liquefaction and ground liquefaction, characterized in that a tip bit that is detachably attached to the tip is formed of cement containing garnet, and a hollow cylindrical drainage material is connected to the tip bit. The tip bit is attached by engaging with the casing auger so that the rotation from one direction is transmitted, and the connection between the tip bit and the drainage material has a large number of holes on the circumferential surface. This is a drain stake constructed with pipes.

[0011]

A hollow cylindrical drainage material is housed in a casing auger for drilling a well hole, and the tip bit is detachably engaged and attached so that only rotation in one direction can be transmitted. By connecting the drainage material and burying the tip bit as an anchor for the drainage material after drilling, the drainage material can be easily buried and the drainage material does not float up and remains stable for a long time. Can be maintained.

[0012]

EXAMPLE Next, the present invention will be described in more detail with reference to the illustrated example. In FIG. 1, reference numeral 1 is the sand geology / ground that is the object of liquefaction prevention. Use a hole drilling device such as an auger to obtain a specified size (100-2
00 mm) and depth (3 to 15 m) are drilled, and a drain pile made of a drainage material having a cylindrical shape is buried or constructed in the well hole.

In this case, as a device for drilling a well hole, for example, a drilling device 2 in which a machine-installed rubber caterpillar excavator is improved is used, and a columnar slide base 4 is attached to the tip of an arm 3 of the drill. The rotation drive device 5 is slidably attached to the base.

The rotary drive device 5 can be operated to rotate and slide at the driver's seat of the drilling device 2, and a cylindrical casing auger 6 is attached to the rotary drive device 5 so as to be rotationally driven. A tip bit 7 made of concrete is detachably attached to the tip of the casing auger 6.

As shown in FIG. 2, the tip bit 7 has a fin 8 for an auger integrally formed on the peripheral surface thereof, and a projection 9 for connection with the casing auger 6 is formed. A locking portion 10 for locking rotation in one direction (clockwise) is provided on the outer peripheral surface of the connecting convex portion 9, and a projection 11 for mounting a cylindrical drainage material is further integrated on the upper surface of the connecting convex portion 9. Is formed in the same way. The shape of the tip bit is
An inverted pyramid type or an inverted pyramid type that does not have fins may be used.

The engaging portion 10 is composed of at least one inclined portion 10a inclined in one direction and a cliff portion 10b. In the illustrated embodiment, two inclined portions are formed on the outer peripheral surface of the connecting convex portion 9. The portion 10a and the two cliffs 10b are formed at symmetrical positions. The tip bit 7 may be mixed with garnet in order to increase its hardness.

The cylindrical drainage material 12 attached to the tip bit 7 is a resin string, that is, a linear polypropylene of about 2 mm is heated and melted, extruded from a nozzle, and laminated in a curled state in order to form a mutual filament. It is composed of a core material 13 (generally available on the market: Hetimaron-Shinko Nylon Co., Ltd.) in which a contact is welded and molded into a hollow cylindrical shape, and a filter material 14 which is wound around and fixed to the outer peripheral surface thereof.

The drainage material 12 has a core hole 15 of a predetermined size formed in the central portion along the length thereof, is substantially flexible and has a high pressure resistance, and the surface porosity thereof is 95-. The porosity is 97% and the porosity is 80 to 95%, and the porosity is 80% when the load is about 10 t / m 2.

The filter material 14 may be made of any suitable woven fabric or non-woven fabric, and for example, non-woven fabric made of polypropylene long fibers is most preferably used.

The drainage material 12 as described above is attached to the tip bit 7 by a resin pipe 16 penetrating the core hole 15 of the core material 13 and having substantially the same size as the core material 13.

In this case, the pipe 16 has a large number of holes 1 on its peripheral surface.
7 is used, the lower end portion of the pipe 16 is fitted to the connecting convex portion 9 of the tip bit 7 and fixed by an appropriate fixing means such as an adhesive means, and the lid member 18 is attached to the upper end portion. By attaching, the drainage material 12 is sandwiched and fixed by the tip bit 7 and the lid material 18.

The lid member 18 used is made of resin and has a cylindrical convex portion 19 projectingly formed at the center of the lower surface thereof, and a large number of holes 20 provided over the entire surface of the lid member. The cylindrical convex portion 19 is attached to the upper end portion of the pipe 16 and fixed by an adhesive means or the like.
It is a so-called drain stake.

The drain pile thus constructed, that is, the drainage material 12, is inserted and housed inside the cylindrical casing auger 6, and the tip bit 7 is fitted to the lower end portion of the casing auger 6 so that it can rotate only in one direction. Are engaged for transmission.

That is, on the inner peripheral surface of the lower end of the casing auger 6, there is provided an engaging portion (not shown) composed of an inclined portion corresponding to the engaging portion 10 of the tip bit 7 and a cliff, and these engaging portions. By attaching the tip bit 7 to the tip portion of the casing auger 10 so that the engaging portion 10 and the engaging portion are aligned with each other, the tip bit 7 can be rotated only in one direction, for example, clockwise.
Is configured to be transmitted to.

After the tip bit 7 and the drainage material 12 are set in the casing auger 6 in this way, the drilling device 2 is operated and the arm 3 thereof is operated as shown in FIGS.
Is driven to set the slide base 4 and the casing auger to a predetermined position in an upright state, and the rotation driving device 5 is driven to rotate the casing auger 6 for drilling.

In the case of this drilling, the casing auger 6 rotates in one direction, that is, the clockwise direction, and the tip bit 7 also rotates in accordance with the rotation thereof, and sequentially advances into the sand geology / ground 1 to a predetermined depth. Hole is drilled. The depth of this hole is determined in advance by investigating the condition of the sand geology and the ground 1, a casing auger of a length corresponding to that is used, and the drainage material 12 corresponding to the length is stored. There is.

When the drilling work reaches the planned depth,
When the drive device 5 is driven to rotate the casing auger 6 in the reverse direction, the engagement state between the engagement portion of the casing auger 6 and the locking portion 10 of the tip bit 7 is dissociated, and as shown in FIG.
The rotation is not transmitted to the tip bit 7, and the casing auger 6 is sequentially retracted.

At this time, the tip bit 7 is in a state of biting into the sand geology / ground 1 by the fins 8 and is not dragged even if the casing auger 6 retracts. Therefore, the tip bit 7 functions as an anchor, and the tip bit 7
The drainage material 12 attached to the is sequentially removed from the casing auger 6 and remains in the drilled hole.

In order to prevent the drainage material 12 from being forcibly pulled out or stretched by frictional engagement between the inner peripheral surface of the casing auger 6 and the drainage material 12 in the pulling operation of the casing auger 6, As shown in FIG. 5, the weight W may be placed in the casing auger 6 and above the drainage material 12, and the casing auger 6 may be pulled out by pressing the weight W.

In this way, holes are sequentially drilled at predetermined intervals, and the drainage material 12 is left together with the tip bit 7 in each of the drilled well holes. As a result, the drainage material 12 is sandy geological ground / ground 1
It can be buried as a drain pile inside. The drilling and embedding intervals may be carried out at intervals of about 0.5 to 5 m, depending on the sand geology and ground conditions.

Then, the drainage material 12 inserted into the well hole 12
The upper end portion of may be projected several centimeters as it is, or may be buried slightly lower than the surface of the earth, and a crushed stone layer having a predetermined thickness may be formed on the upper portion thereof to form a substantial lid.

In the above description, the well hole is drilled substantially vertically. However, if the slide base 4 is installed while being tilted at an appropriate angle, a hole corresponding to the tilt angle is drilled. Along with the inclination angle, drainage material 12
Can be buried.

Incidentally, in the sand geology / ground 1, there is a case where a water impermeable layer 1a made of clay, silt or the like exists in the middle. The water-impermeable layer has a very fine particle size, and the fine particles may be sequentially melted and adhered to the filter material 14, and may be sequentially deposited in the drainage material 12 to cause a substantial clogging phenomenon.

In such a case, in order to prevent the fine particles from leaching out, a material that does not allow water to pass through the outer peripheral surface of the filter material 14 at a portion corresponding to the water-impermeable layer in advance, such as vinyl tape. May be wound to form the non-water-permeable portion.

In any case, if the tip bit 7 is left as a kind of anchor material at the time of drilling the well hole with the casing auger 6, in any case,
Drainage material 12 can be prevented from floating and drainage material 1
The burying work of 2 can be easily performed.

[0036]

As described above, the method of constructing the drainage pile for preventing the liquefaction of the sand geology and ground according to the present invention is performed by drilling a well hole having a predetermined size and a predetermined depth in the sand geology and the ground. A tip bit is detachably attached to the tip of the casing auger to be bored, a hollow cylindrical drainage material is connected to the tip bit, and the drainage material is housed in the casing auger for drilling,
By embedding the drainage material while leaving the tip bit as an anchor after the drilling, the underground pile or construction work of the drain pile can be remarkably facilitated, and the drain pile can be properly placed at the planned place. It has an excellent effect that it can be installed in.

Further, the sand geology / ground liquefaction prevention drain pile is a tip detachably attached to the tip of a casing auger for boring a well hole of a predetermined size and a predetermined depth in the sand geology / ground. By forming the bit with cement containing garnet and connecting a hollow cylindrical drainage material to the tip bit, drilling work can be performed quickly, and leaving the tip bit as an anchor causes a phenomenon of floating. This is an excellent effect that it can be solved and the buried state can be maintained stably for a long period of time, whereby the geology of sand and the liquefaction of the ground can be prevented for a long period of time.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing a method of constructing a sand pile geological / ground liquefaction prevention drain pile according to the present invention.

FIG. 2 is a perspective view showing the drainage pile for preventing liquefaction separated and partially omitted.

FIG. 3 is a side view showing only a main part for explaining a construction state of the drainage pile for preventing liquefaction.

FIG. 4 is a side view showing only a main part for explaining a construction situation similar to that of FIG.

FIG. 5 is an explanatory view showing only a main part for explaining a construction state of the drainage pile for preventing liquefaction.

[Explanation of symbols] 1 Sand geology / ground 1a Impervious layer 2 Drilling device 3 Arm 4 Slide base 5 Rotation drive device 6 Casing auger 7 Tip bit 8 Fin 9 Connecting convex portion 10 Locking portion 10a Inclined portion 10b Cliff wall Part 11 Projection 12 Drainage material 13 Core material 14 Filter material 15 Core hole 16 Resin pipe 17,20 Many holes 18 Lid material 19 Cylindrical convex part

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (71) Applicant 592195056 Kazuo Kamura 5-11-2 Hanazono, Hanamigawa-ku, Chiba-shi, Chiba (71) Applicant 592195067 Osamu Kazeoka 3-12-3-207, Masago, Mihama-ku, Chiba-shi ( 71) Applicant 592195078 Asahi Construction Co., Ltd. 3-1 Market-cho, Chuo-ku, Chiba City, Chiba Prefecture (71) Applicant 592195089 Keisei Construction Co., Ltd. 4-17-3 Miyamoto, Funabashi City, Chiba Prefecture (71) Applicant 592195090 Engineering Construction Co., Ltd. 2-13-12 Minamimachi, Chuo-ku, Chiba City, Chiba Prefecture (71) Applicant 592195104 Abe Construction Co., Ltd. 832-7, Asahi City, Chiba Prefecture (71) Applicant 592195115 Shirai Construction Co., Ltd. 2-4- Tsudanuma, Narashino City, Chiba Prefecture 21 (71) Applicant 592195126 Nozaki Construction Co., Ltd. 223-3 Shinko, Mihama-ku, Chiba-shi, Chiba Prefecture (72) Inventor Kenji Ishihara 2415-123 (72) Inventor, Nara-cho, Midori-ku, Yokohama-shi, Kanagawa Prefecture Hisai Usai 397-22 Sano-cho, Inage-ku, Chiba-shi, Chiba Prefecture (72) Inventor Yoshitada Yoshida 401-196 Jiyugaoka, Kukizaki-cho, Inashiki-gun, Ibaraki Prefecture (72) Takashi Kusuda 260-141 Omori-cho, Chuo-ku, Chiba-shi (72) 72) Inventor Kazuo Kamura 5-11-2 Hanazono, Hanamigawa-ku, Chiba-shi, Chiba Prefecture (72) Inventor Osamu Kazeoka 3-12-3-207, Masago, Mihama-ku, Chiba-shi, Chiba (72) Kennori Matsumoto Chiba-shi, Chiba-ken 3-1 Asahi Construction Co., Ltd., Chuo-ku Market (72) Inventor Tetsuya Ando 4-17-3 Miyamoto, Funabashi City, Chiba Prefecture Keisei Construction Co., Ltd. (72) Inventor Kenji Ogura 2 Minami-machi, Chuo-ku, Chiba City, Chiba Prefecture −13−12 In Construction Co., Ltd. (72) Inventor Hibumi Abe 832-7 Ro, Asahi-shi, Chiba Abe Construction Co., Ltd. (72) In-house Yasuhiko Shirai 2-4-21 Tsudanuma, Narashino, Chiba Ken Shirai Incorporated Co., Ltd. (72) Inventor Takuji Nozaki Nozaki 223-3 Shinko, Mihama-ku, Chiba City, Chiba Prefecture

Claims (5)

[Claims] 1. A tip bit is detachably attached to a tip of a casing auger for drilling a well hole of a predetermined size and a predetermined depth in a sand ground, and a hollow cylindrical drainage material is connected to the tip bit, A method for constructing a drain pile for preventing liquefaction of sand ground, characterized in that the drainage material is housed in a casing auger and drilled, and the drainage material is buried while leaving the tip bit as an anchor after the drilling. 2. The construction method according to claim 1, wherein the tip bit is attached by engaging with the casing auger so that the rotation from one direction is transmitted. 3. The construction method according to claim 1, wherein the tip bit is formed of cement mixed with garnet. 4. A tip bit detachably attached to a tip of a casing auger for drilling a well hole of a predetermined size and a predetermined depth in a sand ground is formed of garnet-containing cement, and the tip bit is a hollow columnar shape. Drain pile for preventing liquefaction of sand ground characterized by connecting drainage materials of. 5. The liquefaction-preventing drain pile for sand ground according to claim 4, wherein the tip bit and the drainage material are connected by a pipe having a large number of holes on the peripheral surface.