JP2642577B2 - Construction method of drain pile to prevent liquefaction of sand geology and ground and its drain pile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to artificially formed land such as a landfill or embankment, as well as to the geology and ground of sand where the groundwater level is high and soft in the sea or riverside land.
The present invention relates to a method for embedding a drain pile buried in a column shape in the ground to prevent liquefaction caused by an earthquake, and a drain pile thereof.

[0002]

2. Description of the Related Art Liquefaction of this kind of sand geology and ground is a phenomenon in which soft sand geology and ground become unstable like 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 method for preventing such liquefaction, a drain pipe method and a crushed stone drain method are known as conventional examples.

In the drain pipe method, for example, a plastic pipe having a diameter of 10 cm and a length of 9 m and having a large number of holes is used, and a thin sheet of woven cloth is formed on the outer peripheral surface of the pipe. The drain pipe around which the filter material is wound is housed in a predetermined casing auger, and the casing auger is configured such that a bit at the tip thereof can be opened and closed. A hole of a predetermined depth is excavated, the bit at the tip is opened, and a drain pipe in the casing auger is left in the hole, and the casing auger is pulled out. This is a method of burying drain pipes.

The crushed stone drain method uses a hollow pipe auger having a freely openable and closable tip, excavates a hole having a diameter of, for example, about 50 cm and a depth of about 20 m in the target geology and ground, and opens the tip to form a medium. A method of forming a crushed stone pillar by forming a crushed stone pillar at predetermined intervals by pulling out a hollow tube auger while charging crushed stone into an empty tube auger and squeezing the crushed stone.

The drain pipe and the crushed stone pillar in these conventional examples both suppress a liquefaction phenomenon by digging a kind of well in the sand geology and the ground, and releasing the underground water pressure increased during the occurrence of the earthquake from the well to the surface of the ground. Is what you do.

[0006]

In the construction of the drain pipe method, the tip of the casing auger is opened to leave the drain pipe inside, but if the opening and closing of the tip is not sufficient, the casing auger is not opened. However, there is a problem in the construction that the drain pipe cannot be buried at a predetermined depth because it is lifted together with the drain pipe.

Further, even if a relatively weak earthquake occurs after the drain pipe is buried, the drain pipe may be lifted by the pushing action due to an increase in groundwater pressure. It cannot be submerged in the sea, it must be obstructed in some places, and the protruding part must be removed, and then, when it comes to an emergency (when an earthquake of about 5 or more occurs at the Japan Meteorological Agency seismic intensity class) its function Can not be fulfilled.

In the crushed stone drain method, crushed stone is put into a well bore excavated through a hollow pipe auger,
The work of digging in a groping state that is completely invisible from the outside is not only poor workability in the construction work, but also when the groundwater level rises due to rainfall, earthquake, etc. There is a problem that the gap gradually fills and gradually fills the gap, and the function cannot be sufficiently performed at the time of emergency.

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

[0010]

SUMMARY OF THE INVENTION As a specific means for solving the problems of the prior art, the present invention is directed to a case auger for drilling a well hole having a predetermined size and a predetermined depth in the sand geology and ground. removably attaching a tip bit, stacked with curled a string of predetermined diameter tip bits
The hollow cylindrical drainage material is connected, the drainage material is housed in a casing auger, and after drilling, the drainage material is used as a drain pile while leaving the tip bit as an anchor.
The hollow cylindrical drainage material may be
Connected to the tip bit through a pipe with a number of holes on the peripheral surface
And the tip of the casing auger and the tip bit
Are connected by engaging means, and the casing auger is
When rotating in the hole direction, the engaged state is maintained and the tip bit
Are rotated together to drill a well hole with a predetermined depth.
The engagement disengages when rotated in the opposite direction and the casing
The auger is pulled out, leaving the tip bit and drainage material in the well hole.
A method of constructing a drain pile for preventing liquefaction of the sand geology and the ground, and a tip of a casing auger for drilling a well hole of a predetermined size and a predetermined depth in the sand geology and the ground, characterized in that the tip bit detachably attached to form cement garnet containing, prior to tip-bit
Forming a connecting projection with the casing auger;
It is intended to provide a drain pile for preventing liquefaction of soil geology and ground, wherein a hollow columnar drainage material is connected via a pipe having a number of holes on a peripheral surface in a convex portion, Rotation in one direction is transmitted to the engagement means of the tip bit
At least one slope and cliff
Attached and connected to the tip of the single auger
The connection between the connecting protrusion and the pipe is provided at the center of the connecting protrusion.
This is done by using a projection .

[0011]

[Function] A hollow cylindrical drainage material is stored in a casing auger for drilling a well hole, and a tip bit is connected to the drainage material.
And the connection between the tip bit and the casing auger is reduced.
Engagement means so that rotation can be transmitted only during rotation in the hole direction
Is detachably engaged by the
Drilling action with the drill bit, that is, rotation in the drilling direction
In both cases, bring the drainage material to the specified depth, and then
By rotating the auger in the pulling direction, the case
And the tip bit is disengaged and the tip bit is disengaged.
Drainage material will be left in the well bore with
Since the tip bit acts as an anchor for drainage,
The work of burying the drainage material is easy, and the buried state can be stably maintained for a long time without the drainage material floating.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in more detail with reference to the illustrated embodiment. In FIG. 1, reference numeral 1 denotes the geology and ground of sand to be prevented from liquefaction. Using a drilling device such as an auger, a predetermined size (100 to 2
(00 mm) and a depth (3 to 15 m) of a well hole, 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 obtained by improving a rubber caterpillar shovel mounted on a machine 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 driving device 5 is capable of rotating and sliding operation at the driver's seat of the drilling device 2. The rotary driving device 5 has a cylindrical casing auger 6 mounted so as to be driven to rotate. A concrete tip bit 7 is detachably attached to the tip of the casing auger 6.

As shown in FIG. 2, the tip bit 7 has an auger fin 8 integrally formed on a peripheral surface thereof, and has an engaging means with the casing auger 6 , ie, a connecting member. The connecting projection 9 is integrally formed , and an outer peripheral surface of the connecting projection 9 is provided with a locking portion 10 for locking rotation in one direction (clockwise direction or drilling direction ). A projection 11 for attaching a columnar drainage material is integrally formed on the upper surface of the substrate. The shape of the tip bit may be an inverted pyramid type or an inverted pyramid type having no fin.

The engaging portion 10 comprises at least one inclined portion 10a inclined in one direction and a precipitous portion 10b. In the illustrated embodiment, two inclined portions are provided on the outer peripheral surface of the connecting convex portion 9. The part 10a and the two precipitous parts 10b are formed at symmetrical positions, and the inclined part 10a and the precipitous part 10b are
The casing auger 6 is cut by the locking portion 10.
The connection is made only when rotating in the hole direction . The tip bit 7 may be mixed with garnet in order to increase its hardness.

The columnar drainage material 12 attached to the tip bit 7 is prepared by heating and melting a resin string, that is, linear polypropylene of about 2 mm, extruding it from a nozzle, and sequentially laminating in a curled state. It is composed of a core material 13 (a commercially available trade name: Hetimaron-Shinko Nylon Co., Ltd.) formed by welding contacts into a hollow cylindrical shape, and a filter material 14 wound and fixed on the outer peripheral surface thereof.

The drainage member 12 has a core hole 15 of a predetermined size formed in the center thereof along the length direction. The drainage member 12 is substantially flexible, has high pressure resistance, and has a surface porosity of 95 to 95%. The porosity is 97%, the porosity is 80 to 95%, and the porosity is 80% when the load is approximately 10 t / m2.

As the filter material 14, an appropriate woven or nonwoven fabric can be used. For example, a polypropylene long fiber nonwoven fabric is used as the most preferable example.

The drainage member 12 is attached to the tip bit 7 by a resin pipe 16 having substantially the same dimensions as the core member 13 penetrating the core hole 15 of the core member 13.

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

The lid 18 used is made of resin, has a cylindrical projection 19 projecting from the center of the lower surface, and has a large number of holes 20 formed over the entire surface of the lid. The cylindrical body 19 is mounted on the upper end of the pipe 16 and fixed by an adhesive means or the like.
It becomes a so-called drain pile.

The drain pile constructed as described above, 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 of the casing auger 6 to rotate in only one direction. Are transmitted so as to be transmitted.

That is, on the inner peripheral surface of the lower end portion of the casing auger 6, there is provided an engaging portion (not shown) comprising a slope portion and a cliff portion corresponding to the locking portion 10 of the tip bit 7, and these locking portions are provided. By attaching the tip bit 7 to the tip of the casing auger 6 so that the engagement bit 10 and the engagement portion match, only the rotation in one direction, for example, the drilling direction (clockwise) is transmitted to the tip bit 7. Is done.

After the tip bit 7 and the drainage material 12 have been set in the casing auger 6 in this way, as shown in FIGS.
Is driven to set the slide base 4 and the casing auger 6 at a predetermined position in an upright state, and the rotary drive device 5 is driven to rotate the casing auger 6 to perform drilling.

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

When the drilling operation reaches a predetermined depth,
When the driving device 5 is driven to rotate the casing auger 6 in the reverse direction, the engagement between the engaging portion of the casing auger 6 and the engaging portion 10 of the tip bit 7 is disengaged, 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 being cut into the sand geology / ground 1 by the fin 8, and is not dragged even if the casing auger 6 is retracted. Therefore, the tip bit 7 serves as an anchor, and the tip bit 7
The drainage material 12 attached to the casing auger sequentially comes out of the casing auger 6 and remains in the hole thus drilled.

To prevent the drainage material 12 from being forcibly pulled out or stretched by the frictional engagement between the inner peripheral surface of the casing auger 6 and the drainage material 12 during the operation of pulling out the casing auger 6, FIG. As shown in FIG. 5, the weight W is placed in the casing auger 6 and above the drainage material 12, and the casing auger 6 is rotated while rotating in the direction opposite to the drilling direction so as to be pressed. You just need to cut it out.

In this way, the drilling is sequentially performed at a predetermined interval, and the drainage material 12 is left together with the tip bit 7 in each of the drilled well holes.
It can be buried as a drain pile inside. The drilling and burying interval depends on the geology of the sand and the condition of the ground, but the drilling may be performed at intervals of about 0.5 to 5 m.

The drainage material 12 inserted into the well hole
The upper end may be projected a few centimeters as it is, or may be buried slightly lower than the surface of the earth, and may be substantially covered with a crushed stone layer having a predetermined thickness, for example.

In the above description, a case has been described in which the well hole is drilled substantially vertically. However, if the slide base 4 is installed to be inclined at an appropriate angle, a drill hole corresponding to the inclined angle is formed. At the same time, the drainage material 12
Can be buried.

Incidentally, in the geology and ground 1 of the sand, there may be a case where a poorly permeable layer 1a made of clay, silt or the like is present in the middle. The water-impermeable layer has a very fine particle size, and the fine particles gradually melt out and adhere to the filter material 14, and are sequentially deposited in the drainage material 12, which may cause a substantial clogging phenomenon.

In such a case, in order to suppress the dissolution of fine particles, 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, for example, a vinyl tape or the like May be wound to form a non-water-permeable portion.

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

[0036]

As described above, the method for constructing a drain pile for preventing liquefaction of the sand geology and the ground according to the present invention is to cut 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 stored in the casing auger and drilled. A method of burying the drainage material as a drain pile while leaving as
Engaging means between the tip of the casing auger and the tip bit
And the casing auger turns in the drilling direction.
When rotating, the engaged state is maintained and the tip bits rotate together.
The well hole of the specified depth is drilled and opposite to the drilling direction
The casing auger is disengaged.
So that the tip bit and drainage material remain in the well bore.
Drilling action by the casing auger
It is only possible to bring the drainage material to a predetermined depth in the well hole.
Can, and place the casing auger in the direction opposite to the drilling direction
Just rotate and pull out the tip bit.
In both cases, drainage can be left in the well bore,
Also, drainage material is first passed through a pipe with a number of holes on the peripheral surface.
The connection strength is stable because it is connected to the end bit
The casing auger can be easily pulled out
Thus, an excellent effect is achieved in that the drainage material can be extremely easily buried or constructed underground as a drain pile .

The liquefaction prevention drain pile according to the present invention comprises 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 the sand geology and ground. The tip bit is formed of cement with garnet.
Formed on the peripheral surface of the connecting projection.
By connecting the hollow columnar drainage material through the pipe, the drain pile embedded in the well hole is
The bit acts as an anchor and the pipe is
It is located penetrating the central part,
Even if the temperature rises rapidly, the floating phenomenon is suppressed, and the excellent effect of maintaining the shape of the drainage material for a long time and preventing liquefaction of the sand ground can be achieved.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing the liquefaction prevention drain pile separated and partially omitted.

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

FIG. 4 is a side view showing only a main part for describing a construction situation similar to FIG. 3;

FIG. 5 is an explanatory diagram showing only a main part for explaining a construction state of the liquefaction prevention drain pile.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Geology and ground of sand 1a Impervious layer 2a Drilling device 3 Arm 4 Slide base 5 Rotation driving device 6 Casing auger 7 Tip bit 8 Fin 9 Connecting projection 10 Locking portion 10a Inclined portion 10b Cliff 11 Projection 12 Drainage Material 13 Core material 14 Filter material 15 Core hole 16 Resin pipe 17, 20 Numerous holes 18 Lid material 19 Cylindrical projection

 ──────────────────────────────────────────────────続 き Continuing from the front page (73) Patent holder 592195056 Kazuo Kamura 5-11-2 Hanazono Ward, Hanamigawa-ku, Chiba Chiba Prefecture (73) Patent holder 592195067 Osamu Fukaoka 3-12-3-Masa, Mihama-ku, Chiba Chiba 207 (73) Patent holder 592195078 Asahi Construction Co., Ltd.3-1, Machimachi, Chuo-ku, Chiba-shi, Chiba (73) Patent holder 592195089 Keisei Construction Co., Ltd. 4-17-3, Miyamoto, Funabashi-shi, Chiba-ken (73) Patent holder 592195090 Industrial Construction Co., Ltd. 2-13-12 Minamicho, Chuo-ku, Chiba City, Chiba Prefecture (73) Patent holder 592195104 Abe Construction Co., Ltd. 832-7, Ro, Asahi-shi, Chiba Prefecture (73) Patent holder 592195115 Shirai Construction Co., Ltd.Chiba 2-4-21 Tsudanuma, Narashino (73) Patent holder 592195126 Nozaki Construction Co., Ltd.223-3 Shinko, Mihama-ku, Chiba-shi, Chiba (72) Inventor Kenji Ishihara Nara, Midori-ku, Yokohama-shi, Kanagawa 2415-123 (72) Inventor Hisashi Hisai 397-22 Sanno-cho, Inage-ku, Chiba-shi, Chiba Pref. 260-141, Omoricho, Chuo-ku (72) Inventor Kazuo Kamura 5-11-2 Hanazono-ku Hanazono, Chiba-shi, Chiba Prefecture (72) Inventor Osamu Fukaoka 3-12-3-207, Masago, Mihama-ku, Chiba-shi, Chiba Prefecture (72) Inventor Noriyuki Matsumoto 3-1 Asahi Ken Construction Co., Ltd., Chuo-ku, Chiba City, Chiba Prefecture (72) Inventor Tetsuya Ando 4-17-3 Miyamoto, Funabashi City, Chiba Prefecture Keisei Construction Co., Ltd. (72) Inventor Kenji Ogura (72) Inventor Hirofumi Abe 832-7 Asahi-shi, Chiba Abe Construction Co., Ltd.In-house (72) Inventor Yasuhiko Shirai Tsudanuma, Narashino-shi, Chiba 2-4-21 Shirai Construction Co., Ltd. (72) Inventor Takuji Nozaki 223-3 Shinko, Mihama-ku, Chiba-shi, Chiba Nozaki Construction Co., Ltd. (56) References JP 61-169520 (JP, A)

Claims (5)

(57) [Claims] 1. A detachable tip bit is attached to the tip of a casing auger for drilling a well hole of a prescribed size and a prescribed depth in the sand geology and ground, and a strike of a prescribed diameter is attached to the leading bit.
After connecting the hollow cylindrical drainage material laminated in a state where the ring is curled , storing the drainage material in a casing auger and drilling, the drainage material is used as a drain pile while leaving the tip bit as an anchor. How to bury
Therefore, the hollow columnar drainage material has a large number of holes on its peripheral surface.
Connected to the tip bit through a pipe
The tip of the gouger and the tip bit are connected by engaging means.
When the casing auger rotates in the drilling direction
The engagement bit is maintained and the tip bit rotates together and
The well hole with a depth of
The casing auger is disengaged when
A method for constructing a drain pile for preventing liquefaction of soil geology and ground, wherein an end bit and a drainage material are left in a well hole . The engagement means of the tip bit rotates in one direction.
At least one slope and a precipice so that
To engage the tip of the casing auger
Construction method according to claim 1 being. 3. The construction method according to claim 1, wherein the tip bit is formed of cement mixed with garnet. 4. A tip bit removably attached to a tip of a casing auger for drilling a well hole of a predetermined size and a predetermined depth in the sand geology and ground is formed of cement containing garnet, and the tip bit is formed on the tip bit . With the casing auger
Forming a connecting protrusion, and forming a number of holes in the connecting protrusion on the peripheral surface.
A drain pile for preventing liquefaction of the sand geology and ground, wherein a hollow columnar drainage material is connected via a pipe having the same . 5. The connection between the connecting projection and the pipe is made by connecting
5. The drainage pile for preventing liquefaction of sand geology and ground according to claim 4, wherein the drain pile is formed by a projection provided at a central portion of the projection .