JPH0665913A - Liquefaction prevention method for sandy soil/ground - Google Patents

Abstract

PURPOSE:To easily construct the ground by laminating resin strings in the shape of a hollow column inside a plurality of well holes installed on the a sand ground and welding the connected parts of the strings and burying a waste water material whose outer peripheral surface is wound with filter material. CONSTITUTION:A well hole 2 whose size and depth are specified is bored on a sand ground 1 at a specified span. In addition to the hole, resin strings are laminated in the shape of a hollow column in a curled state where the connected parts of the strings are welded with each other. A filter material 6 is wound around the outer peripheral surface, thereby forming a waste water material whose porosity exceeds 80%. The waste water materials 3 are buried into the well hole 2 respectively.

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 of preventing aging.

[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. It is a construction method in which a plurality of wound filter materials are vertically embedded in the target sand ground at predetermined intervals.

The crushed stone draining method is a method in which a plurality of holes having a diameter of 50 cm and a depth of about 20 m are excavated at a predetermined interval in a target sand ground, and crushed stones are put into the holes to be solidified. .

In each of these conventional examples, a kind of well is dug in the sand ground, and the groundwater pressure that has risen when an earthquake occurs is released from the well to the surface of the ground to suppress the liquefaction phenomenon.

[0006]

In the above-mentioned drain pipe construction method, the outer peripheral surface of a plastic pipe having a large number of holes is covered with a sheet-shaped filter material, and the intervals of the large number of holes are wide. Not only is it impossible to drain water due to a sudden rise in groundwater pressure, but the filter material corresponding to the open holes only acts locally, significantly reducing the filter function, which also causes a sudden increase in groundwater pressure. It has a problem that it cannot cope with the rise.

On the contrary, if the distance between the holes formed is reduced,
Although the water collection is improved, the strength of the pipe itself, that is, the pressure resistance to earth pressure deteriorates, and the pipe is crushed by earth pressure due to long-term burial and multiple small earthquakes, causing an emergency (Seismic intensity 5-6). When an earthquake occurs, the function cannot be fulfilled.

Further, in the above-mentioned crushed stone drain method, since crushed stones are thrown into the excavated well hole and hardened, not only the workability of the construction work is poor, but also the groundwater level rises due to rainfall and earthquakes. At times, the sand gradually enters the gaps of the crushed crushed stones and gradually fills the gaps, which also causes a problem that the function cannot be fully fulfilled in the event of an emergency.

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 to drill well holes of a predetermined size and a predetermined depth at a predetermined interval in a sand ground, and to form these well holes. In the sand ground, which is characterized in that the resin strings are laminated in a hollow columnar shape in a curled state, the contact portions of the strings are welded, and the drainage material wound around the outer peripheral surface is buried. The present invention provides a method for preventing liquefaction, wherein the drainage material has a porosity of 80% or more, and a long-fiber non-woven fabric made of resin is used as the filter material, and the buried drainage material is in a vertical direction or an oblique direction. Either in the horizontal direction or a combination of these, a crushed stone layer is formed on the top of the buried drainage material to form a lid, and a non-water-permeable portion is formed in the drainage material filter material corresponding to the stratum. I will do it It is obtained by the.

[0011]

[Function] Since the drainage material with a porosity of 80% or more is used in the well hole, groundwater will come into the drainage material from all parts of the filter material wrapped around the outer peripheral surface. Almost no clogging phenomenon is seen,
Moreover, since the drainage material itself has excellent pressure resistance, the shape of the well hole can be maintained for a long period of time.

[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. A well hole 2 having a predetermined size (100 to 200 mm) and a depth (3 to 15 m) is drilled by using, and a cylindrical drainage material 3 is inserted and embedded in the well hole.

The cylindrical drainage material 3 is formed by heating and melting a resin string, that is, a linear polypropylene of about 2 mm, extruding it from a nozzle, curling it, and sequentially laminating it, and welding the mutual contact points of the filaments. It is molded into a hollow cylindrical shape and is generally commercially available (trade name: hemitalone-Shinko Nylon Co., Ltd.).

The drainage material 3 has a predetermined hole 4 formed in the central portion along the length thereof, is substantially flexible and has a high pressure resistance, and the surface porosity thereof is 95-9.
7%, porosity 80-95%, load approximately 10 t / m
The porosity of 2 is 80%.

The filter material 5 is wound around and fixed to the outer peripheral surface of the drainage material 3. The filter material 5 is, for example, a polypropylene long-fiber non-woven fabric as a most preferable example.

The well holes 1 are drilled at intervals of about 0.5 to 5 m, depending on the condition of the sand ground, and the drainage material 3 is inserted into each well hole 2. In this case, for example, the drainage material 3 may be inserted in advance inside the auger, and at the end of drilling, the bit at the tip may be opened to forcibly push the drainage material 3 and remove the auger.

The drainage material 3 inserted in the well hole 1
The upper end portion of may be protruded a few centimeters as it is, or as shown in the figure, it may be buried slightly lower than the surface of the earth, and a lid may be formed by forming a crushed stone layer 6 on the upper portion thereof.

Further, in the sand 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 1a has a very fine particle size, and the fine particles may be sequentially melted and adhered to the filter material 5, and may be sequentially deposited in the drainage material 3, causing 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 5 at the portion corresponding to the water-impermeable layer 1a,
For example, the non-water-permeable portion 7 formed by winding vinyl tape or the like.
To form.

The formation of the non-water-permeable portion 7 allows confirmation of whether or not the water-impermeable layer 1a exists when the sand ground 1 to be liquefaction-prevented is excavated in advance and a geological survey is conducted. Layer 1a
The non-water-permeable portion 7 may be formed by winding a vinyl tape or the like around the outer peripheral surface of the filter material 5 in consideration of the depth corresponding to.

That is, it also includes the selection of the filter material 5 according to the formation, especially in the case of the water impermeable layer 1a, the filter at the position corresponding to the water impermeable layer so as not to enter the drainage material 3. The material 5 is blocked.

Since the specific gravity of the substance of the drainage material 3 is often smaller than 1, a weight 8 may be attached to the tip of the well hole 2 in order to prevent it from floating. The weight in this case is formed of, for example, concrete or the like, and the end portion of the drainage material 3 is embedded in the concrete before the concrete is put into the mold and hardened, so that the drainage material 3 and the weight 8 are integrated. It should be attached.

For example, in the case of a built-up land,
Perform liquefaction prevention as shown in. That is, the water table 12 is generated also in the embankment portion 11, and the water table 1
As shown in FIG. 1, the drainage material 3 is buried in a plurality of places in the place where the liquefaction phenomenon is likely to occur in 2. In this case, it can be embedded vertically or obliquely.

As shown in FIGS. 3 and 4, when a house 13 is already built on the soft sand ground 1, a plurality of houses are vertically provided on the peripheral surface of the house, beyond the water table 12. The drainage material 3 is embedded, and a plurality of oblique drainage materials 3 are embedded from the peripheral surface of the house to the lower part of the house.

Further, as shown in FIGS. 5 and 6, before the house is built on the soft sand ground 1, the whole area of the site including the part under the floor of the house, that is, the vicinity of the base 14, is covered. A large number of drainage materials 3 are buried vertically.

Further, also in the embankment portion 11 for roads or railroads as shown in FIG. 7, a plurality of drainage materials 3 are buried in the vertical direction and the oblique direction similarly to the above. In this case, it is more effective to bury a part of the drainage material 3 in the embankment portion 11 obliquely upward, and a drainage function can be imparted especially during rainfall.

FIGS. 8 and 9 show examples of roads constructed on the soft sand ground 1, respectively. In the case of FIG. 8, a plurality of roads are vertically provided on the foundation 15 and sidewalks 16 of the road. A drainage material 3 of a book is buried, a crushed stone layer 5 is formed on the upper portion of the drainage material 3 to cover the drainage material 3, and the crushed stone layer 5 is communicated with a gutter 17 provided on a side surface of a road. With this configuration,
Groundwater that has rapidly risen through the drainage material 3 escapes from the crushed stone layer 5 to the gutter 17.

In the case of the road shown in FIG. 9, a plurality of drainage materials 3 are arranged in parallel and diagonally from the side surface of the road to the lower part of the foundation portion 15.
Is buried and one end of the drainage material 3 is opened to the gutter 17, so that groundwater from the drainage material 3 escapes directly to the gutter 17. Reference numeral 18 is asphalt that forms the road surface.

In any of the above embodiments, the drainage material 3
Is buried in the soft sand ground 1 vertically, diagonally or horizontally, and by ejecting the groundwater pushed up by the rise in pore water pressure due to an earthquake etc. to the surface of the earth or the gutter for drainage, etc. The liquefaction phenomenon can be suppressed, and the collapse or collapse of houses and roads can be prevented.

Furthermore, when the drainage material 3 itself is buried,
Not only does it function as a building pile for the sand ground 1, but also acts as a vibration absorber, suppressing subsidence and landslides of the building, as well as underground due to running trucks or dump trucks or passing trains. It goes without saying that it also acts to mitigate vibration transmission.

[0031]

As described above, in the method for preventing liquefaction of sand ground according to the present invention, well holes having a predetermined size and a predetermined depth are drilled in the sand ground at predetermined intervals, and the well holes are made of resin. Almost the entire surface of the drainage material is obtained by laying the drainage materials that are laminated by curling the strings in a hollow cylindrical shape, welding the contact parts between the strings, and winding the filter material around the outer peripheral surface. Since the well hole shape is maintained in a state where water can enter from the inside, and the clogging phenomenon of the filter material is hardly seen even for a long period of time,
Once the drainage material is buried, there is an excellent effect that the liquefaction phenomenon of the sand ground can be suppressed almost semipermanently.

Further, since the drainage material has a porosity of 80% or more and a long-fiber non-woven fabric made of resin is used as the filter material, it is lightweight and easy to carry or carry during the construction. Since the drainage material itself is elastic and has excellent pressure resistance, construction work is easy, and the well shape can be maintained for a long period of time, and the drainage function is not lost. .

The buried drainage material is vertical, oblique or horizontal, or a combination thereof, and a crushed stone layer is formed on top of the buried drainage material to form a lid. Even in the sand ground under various conditions, the construction work of preventing liquefaction can be performed, which is an excellent effect.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an essential part showing a method for preventing liquefaction of sand ground according to the present invention.

FIG. 2 is an explanatory diagram showing an example in which the same liquefaction prevention method is applied to an embankment land reclamation site.

FIG. 3 is an explanatory view schematically showing a side surface of an example in which the liquefaction prevention method is applied to a sand ground on which a house has been built.

FIG. 4 is an explanatory view showing a plane of FIG.

FIG. 5 is an explanatory view schematically showing a side surface of an example in which the same liquefaction prevention method is applied to sand ground before building a house.

FIG. 6 is an explanatory view showing a plane of FIG.

FIG. 7 is an explanatory view schematically showing a side surface of an example in which the same liquefaction prevention method is applied to embankment for roads or railways.

FIG. 8 is an explanatory diagram schematically showing a side surface of an example in which the same liquefaction prevention method is applied to a road.

FIG. 9 is an explanatory view schematically showing a side surface of another example in which the liquefaction preventing method is applied to a road.

[Explanation of symbols]

 1 Sand Ground 1a Impervious Layer 2 Well Hole 3 Drainage Material 4 Central Hole 5 Crushed Stone Layer 6 Filter Material 7 Water Impervious Area 8 Weight 11 Filled Area 12 Groundwater Surface 13 Building 14 Base 15 Foundation 16 Sidewalk 17 Gutter 18 asphalt

─────────────────────────────────────────────────── ───

[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] Geology of sand and method for preventing liquefaction of ground

[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 preventing liquefaction caused by an earthquake.

[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. It is a construction method in which a plurality of wound filter materials are buried vertically in the geology / ground of the target sand at a predetermined interval.

In the above-mentioned crushed stone draining method, a plurality of holes having a diameter of 50 cm and a depth of about 20 m are excavated at predetermined intervals in the target sand geology and ground, and crushed stones are put into the holes to be formed by tamping. It is a construction method.

In each of these conventional examples, a kind of well is dug in the sand geology and ground, and the groundwater pressure that rises at the time of an earthquake is released from the well to the surface of the ground to suppress the liquefaction phenomenon. is there.

[0006]

In the above-mentioned drain pipe construction method, the outer peripheral surface of a plastic pipe having a large number of holes is covered with a sheet-shaped filter material, and the intervals of the large number of holes are wide. Not only is drainage not possible due to a sudden increase in groundwater pressure, but the filter material corresponding to the part with holes only acts locally, significantly reducing the filter function and the filter used is woven. Since it is a cloth, it is easily clogged,
In addition, in the initial stage, fine soil particles (sand particles) pass through and accumulate in the drain pipe, which makes it impossible to cope with the rise in groundwater pressure and loses the drain pipe function. There is.

On the contrary, if the distance between the holes formed is reduced,
Although water collection improves, the strength of the pipe itself, that is, the pressure resistance to earth pressure deteriorates, and the pipe is crushed by earth pressure due to long-term burial and multiple small earthquakes, causing an emergency (Seismic intensity class of the Japan Meteorological Agency). When there is an earthquake of about 5 or more, the function cannot be fulfilled.

Further, in the above-mentioned crushed stone drain method, since crushed stones are thrown into the excavated well hole and hardened, not only the workability of the construction work is poor, but also the groundwater level rises due to rainfall and earthquakes. At times, the sand gradually enters the gaps of the crushed crushed stones and gradually fills the gaps, which also causes a problem that the function cannot be fully fulfilled in the event of an emergency.

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 to drill well holes of a predetermined size and a predetermined depth in a sand geology and ground at predetermined intervals,
With the resin strings curled in these well holes, they are laminated in a hollow cylindrical shape and the contact portions between the strings are welded,
Also, the present invention provides a method for preventing liquefaction of sand geology and ground, characterized by embedding drainage materials each having a filter material wound around the outer peripheral surface thereof, wherein the drainage material has a porosity of 80%. Above and as the filter material, a resin long-fiber nonwoven fabric is used, and the buried drainage material is a vertical direction, an oblique direction, a horizontal direction, or a combination thereof, and the buried drainage material A crushed stone layer is formed on the upper part to form a lid, and a non-water-permeable portion is formed on the drainage filter material corresponding to the stratum.

[0011]

[Function] Since the drainage material with a porosity of 80% or more is used in the well hole, groundwater will come into the drainage material from all parts of the filter material wrapped around the outer peripheral surface. Almost no clogging phenomenon is seen,
It is possible to maintain a sufficient drainage capacity for a long period of time, and since the drainage material itself has excellent pressure resistance, it is possible to maintain the shape of the well hole for a long period of time.

[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 the depth (3 to 15 m) of the well hole 2 are drilled,
A cylindrical drainage material 3 is inserted and embedded in the well hole.

The cylindrical drainage material 3 is formed by heating and melting a resin string, that is, a linear polypropylene of about 2 mm, extruding it from a nozzle, curling it, and sequentially laminating it, and welding the mutual contact points of the filaments. It is molded into a hollow cylindrical shape and is generally commercially available (trade name: hemitalone-Shinko Nylon Co., Ltd.).

The drainage material 3 has a predetermined hole 4 formed in the central portion along the length thereof, is substantially flexible and has a high pressure resistance, and the surface porosity thereof is 95-9.
7%, porosity 80-95%, load approximately 10 t / m
The porosity of 2 is 80%.

The filter material 6 is wound around and fixed to the outer peripheral surface of the drainage material 3. The filter material 6 is, for example, a polypropylene long-fiber non-woven fabric as a most preferable example.

The drilling of the well holes 2 is carried out at intervals of about 0.5 to 5 m, depending on the condition of sand geology and ground, and the drainage material 3 is inserted into each well hole 2. To do. In this case,
For example, the drainage material 3 may be inserted in advance inside the auger, and at the end of drilling, the bit at the tip may be opened to forcibly push the drainage material 3 and remove the auger.

Then, the drainage material 3 inserted in the well hole 2
The upper end portion of may be protruded a few centimeters as it is, or as shown in the figure, it may be buried slightly lower than the surface of the earth, and a lid may be formed by forming a crushed stone layer 6 on the upper portion thereof.

Further, in the sand geology / soil 1, there is a case where the impermeable layer 1a made of clay, silt or the like exists in the middle. The water-impermeable layer 1a has a very fine particle size, and the fine particles may be sequentially melted and adhered to the filter material 6, and may be sequentially deposited in the drainage material 3 to 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 6 at the portion corresponding to the hardly water permeable layer 1a,
For example, the non-water-permeable portion 7 formed by winding vinyl tape or the like.
To form.

The formation of the non-water-permeable portion 7 enables confirmation of whether or not the water-impermeable layer 1a is present when excavating the soil geology / ground 1 for liquefaction prevention in advance and conducting a geological survey. The non-water-permeable portion 7 may be formed by winding a vinyl tape or the like around the outer peripheral surface of the filter material 6 in consideration of the depth corresponding to the water-impermeable layer 1a.

That is, it also includes the selection of the filter material 6 according to the stratum. Particularly in the case of the water impermeable layer 1a, the filter at the position corresponding to the water impermeable layer should be prevented from entering the drainage material 3. The material 6 is blocked.

Since the specific gravity of the substance of the drainage material 3 is often smaller than 1, a weight 8 may be attached to the tip of the well hole 2 in order to prevent it from floating. The weight in this case is formed of, for example, concrete or the like, and the end portion of the drainage material 3 is embedded in the concrete before the concrete is put into the mold and hardened, so that the drainage material 3 and the weight 8 are integrated. It should be attached.

For example, in the case of a built-up land,
Perform liquefaction prevention as shown in. That is, the groundwater table 12 is also formed in the embankment 11, and the drainage material 3 is buried in a plurality of locations in the groundwater table 12 where liquefaction is likely to occur, as shown in FIG. In this case, it can be embedded vertically or obliquely.

As shown in FIGS. 3 and 4, when the house 13 is already built on the soft sand geology / ground 1,
A plurality of drainage materials 3 vertically on the circumference of the house.
And a plurality of slanted drainage materials 3 are buried from the peripheral surface of the house to the lower part of the house. Even in this case,
The filter material in the portion of the drainage material 3 which is in contact with the water-impermeable layer 1a is a water impermeable portion.

Further, as shown in FIGS. 5 and 6, before the house is built on the soft sand geology / ground 1, the entire site including the part under the floor of the house, that is, the vicinity of the foundation 14 is included. A large number of drainage materials 3 are vertically embedded in the area.

Further, also in the embankment portion 11 for roads or railroads as shown in FIG. 7, a plurality of drainage materials 3 are buried in the vertical direction and the oblique direction similarly to the above. In this case, it is more effective to bury a part of the drainage material 3 in the embankment portion 11 obliquely upward, and a drainage function can be imparted especially during rainfall.

FIGS. 8 and 9 show soft sand geology / ground 1
FIG. 8 shows examples of the roads constructed above.
In the case of, a plurality of drainage materials 3 are embedded vertically in the foundation 15 and the sidewalk 16 of the road, and a crushed stone layer 5 is formed on the upper part of the drainage material 3 to cover the side surface of the road. It is communicated with the side groove 17 provided in the. With this configuration, groundwater that has rapidly risen through the drainage material 3 can escape from the crushed stone layer 5 to the gutter 17.

In the case of the road shown in FIG. 9, a plurality of drainage materials 3 are arranged in parallel and diagonally from the side surface of the road to the lower part of the foundation portion 15.
Is buried and one end of the drainage material 3 is opened to the gutter 17, so that groundwater from the drainage material 3 escapes directly to the gutter 17. Reference numeral 18 is asphalt that forms the road surface.

In any of the above embodiments, the drainage material 3
Is buried in the soft sand geology / ground 1 vertically, diagonally or horizontally. By ejecting the groundwater pushed up by the rise in pore water pressure due to an earthquake, etc. to the surface of the earth or gutters for drainage, etc. It is possible to suppress the geology of sand and the liquefaction of the ground, and prevent the collapse or collapse of houses and roads.

Furthermore, when the drainage material 3 itself is buried,
It not only plays the role of a building pile for sand geology and ground 1, but also absorbs vibrations, suppresses subsidence and landslides of buildings, and runs trucks or dump trucks or passes trains. Of course, it also acts to mitigate the transmission of underground vibrations based on.

[0031]

As described above, the method for preventing liquefaction of sand geology / ground according to the present invention is to drill well holes of a predetermined size and a predetermined depth in the sand geology / ground at predetermined intervals. ,
With the resin strings curled in these well holes, they are laminated in a hollow cylindrical shape and the contact portions between the strings are welded,
Moreover, by embedding the drainage material wound around the outer peripheral surface with filter material, the well hole shape is maintained in a state where water can enter from almost the entire surface of the drainage material,
Almost no clogging of the filter material can be seen over a long period of time. Therefore, once the drainage material is buried, the sand geology and ground liquefaction phenomenon can be suppressed substantially semipermanently.

Further, since the drainage material has a porosity of 80% or more and a long-fiber non-woven fabric made of resin is used as the filter material, it is lightweight and easy to carry or carry during the construction. Since the drainage material itself is elastic and has excellent pressure resistance, construction work is easy, and the well shape can be maintained for a long period of time, and the drainage function is not lost. .

The buried drainage material is vertical, oblique or horizontal, or a combination thereof, and a crushed stone layer is formed on top of the buried drainage material to form a lid. , The geology of sand under various conditions
Even in the ground, it has an excellent effect that construction work for preventing liquefaction is possible.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an essential part showing a method of preventing liquefaction of sand geology and ground according to the present invention.

FIG. 2 is an explanatory diagram showing an example in which the same liquefaction prevention method is applied to an embankment land reclamation site.

[Fig. 3] The same liquefaction prevention method is used for the geology of sand with a house built
It is explanatory drawing which shows schematically the side surface of the example applied to the ground.

FIG. 4 is an explanatory view showing a plane of FIG.

FIG. 5 is an explanatory view schematically showing a side surface of an example in which the liquefaction prevention method is applied to sand geology / ground before building a house.

FIG. 6 is an explanatory view showing a plane of FIG.

FIG. 7 is an explanatory view schematically showing a side surface of an example in which the same liquefaction prevention method is applied to embankment for roads or railways.

FIG. 8 is an explanatory diagram schematically showing a side surface of an example in which the same liquefaction prevention method is applied to a road.

FIG. 9 is an explanatory view schematically showing a side surface of another example in which the liquefaction preventing method is applied to a road.

[Explanation of code] 1 Sand geology and ground 1a Impervious layer 2 Well hole 3 Drainage material 4 Hole in the center 5 Crushed stone layer 6 Filter material 7 Water impermeable part 8 Weight 11 Filled part 12 Groundwater surface 13 Building 14 Foundation 15 Foundation 16 Sidewalk 17 Gutter 18 Asphalt

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

Front page continuation (71) Applicant 592195056 Kazuo Kamura 5-11-2 Hanazono, Hanamigawa-ku, Chiba-shi, Chiba (71) Applicant 592195067 Osamu Kazeoka 3-12-3-207 (71), Masago, Mihama-ku, Chiba-shi Person 592195078 Asahi Construction Co., Ltd. 3-1 Chuo-ku, Chiba City, Chiba Prefecture, 71 (71) Applicant 592195089 Keisei Construction Co., Ltd. 4-17-3 Miyamoto, Funabashi City, Chiba Prefecture (71) Applicant 592195090 Construction Co., Ltd. Chiba, Chiba Prefecture 2-13-12 Minami-cho, Chuo-ku, Japan (71) Applicant 592195104 Abe Construction Co., Ltd. Asahi-shi, Chiba 832-7 (71) Applicant 592195115 Shirai Construction Co., Ltd. 2-4-21 Tsudanuma, Narashino-shi, Chiba (71) ) Applicant 592195126 Nozaki Construction Co., Ltd. 223-3 Shinko, Mihama-ku, Chiba-shi, Chiba Prefecture (72) Inventor Kenji Ishihara 2415-123 (72) Nara-cho, Nara-ku, Yokohama-shi, Kanagawa Prefecture (72) Hisashi Muei Inaba, Chiba-shi, Chiba Prefecture 397-22 Sanno-cho, Ku (72) Inventor Yoshitada Yoshida 401-196 Jiyugaoka, Kukizaki-cho, Inashiki-gun, Ibaraki (72) Takashi Kusunita 260-141 Omori-machi, Chuo-ku, Chiba, Japan (72) Inventor Kazuo Kamura 5-11-2 Hanazono, Hanamigawa-ku, Chiba-shi, Chiba (72) Inventor Osamu Kazeoka 3-12-3-3 Masamasa, Mihama-ku, Chiba-shi 207 (72) Inventor Kennori Matsumoto 3-1 Asahi Construction Co., Ltd., Chuo-ku, Chiba City, Chiba Prefecture (72) Inventor Tetsuya Ando 4-17-3 Miyamoto, Funabashi City, Chiba Prefecture Keisei Corporation (72) Inventor Kenji Ogura, 2-13-12 Minamimachi, Chuo-ku, Chiba, Chiba Prefecture Construction Co., Ltd. (72) Inventor Hibifumi Abe 832-7, Abe Construction Co., Ltd., Ro, Asahi City, Chiba In-house (72) Inventor Shirai Yasuhiko 2-4-21 Tsudanuma, Narashino City, Chiba Prefecture Shirai Construction Co., Ltd. (72) Inventor Takuji Nozaki 223-3 Shinko, Mihama-ku, Chiba City Chiba Prefecture Nozaki Construction Co., Ltd.

Claims (5)

[Claims] 1. A well ground hole having a predetermined size and a predetermined depth is drilled in a sand ground at a predetermined interval, and a resin string is curled in these well holes to form a hollow columnar structure so that contact portions between the strings are contacted with each other. A method for preventing liquefaction of sand ground, characterized in that the drainage material is welded and the outer peripheral surface is wrapped with a filter material and buried therein. 2. The method for preventing liquefaction of sand ground according to claim 1, wherein the drainage material has a porosity of 80% or more and the filter material is a long-fiber nonwoven fabric made of resin. 3. The method for preventing liquefaction of sand ground according to claim 1, wherein the drainage material to be buried is in any of a vertical direction, an oblique direction, a horizontal direction, or a combination thereof. 4. The method for preventing liquefaction of sand ground according to claim 1, wherein a crushed stone layer is formed on the top of the buried drainage material to form a lid. 5. The method for preventing liquefaction of sand ground according to claim 1, wherein a non-water-permeable portion is formed in the filter material of the drainage material corresponding to the stratum.