JPH09256353A - Ground liquefaction prevention method and water cylinder and burying method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to prevent ground liquefaction without drawing up ground water through a capillary phenomenon in normal time to exhaust excessive pore water occurring by the vibration in the case of an eathquake quickly to the ground. SOLUTION: This front end cone loaded permeable water cylinder 1 is equipped with a front end cone 2, a water cylinder 4 positioned backward of the cone and drawing up no ground water by a capillary phenomenon in normal time and capable of quickly exhausting a large amount of ground water to the ground in the case of an earthquake and a water permeable sheet 8 covering the circumference of the water cylinder. A plurality of front end cone loaded permeable water cylinders are buried at proper intervals. By the constitution, the liquefaction in the case of an earthquake can be surely prevented by burying the front end cone loaded permeable water cylinder in the ground only.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preventing ground liquefaction in the event of an earthquake and a water pipe used therefor and a method for burying it. Does not pump up groundwater, but when excessive pore water is generated due to vibration during an earthquake and groundwater pressure rises, a water pipe with a water passage that allows groundwater to rise to the ground surface is buried vertically or diagonally to the ground surface. The present invention relates to a method for preventing liquefaction of the ground in the event of an earthquake, a water pipe having a special structure for that purpose, and a method for burying this water pipe in the ground.

[0002]

BACKGROUND ART It is well known that underground water is drained by underdrain drainage, and there is a drainage material made of plastic for that purpose, which is practiced in various places. However, such an underdrain drainage system does not discharge the groundwater deep inside the ground simply by draining the underground water close to the surface, let alone discharge the groundwater to the surface early in the event of an earthquake. It did not prevent the liquefaction of the ground. Therefore, in order to prevent groundwater liquefaction by discharging groundwater to the surface early in the event of an earthquake, by forming a crushed stone drain with vertical holes dug in the ground and crushed stones there, excessive vibration caused by the earthquake occurs. Pore water is pumped up.

However, in the conventional crushed stone drain, it was often the case that during the long period until an earthquake occurred, the stones in the crushed stone drain were clogged with earth and sand, and in the event of an earthquake, sufficient drainage was not possible. Therefore, it was necessary to regularly excavate the stone, remove the soil accumulated between the stones and backfill it, and if an earthquake occurs just before the maintenance, the drainage rate of groundwater will be slow due to clogging, It was not possible to prevent sufficient liquefaction.

[0004]

Therefore, in the present invention, construction for installation is simple, there is no need for maintenance due to clogging with earth and sand during normal times, and a large amount of groundwater can be quickly drained to the ground during an earthquake, and the ground is liquefied. The problem to be solved is to develop a method for preventing the liquefaction of the ground that can reliably prevent the above, a water pipe for that purpose, and an embedding method for burying it in the ground.

[0005]

In order to solve the above problems, the present invention provides a tip cone formed at the tip with a hard material such as metal or plastic, and a large number of water inlets are provided behind the cone. The tubular body that has both rigidity and elasticity to the extent that it is not crushed in the ground where a water passage is formed in the surface direction in communication with the water inlet,
The water passage has a water passage cylinder having a cross-sectional area large enough not to cause a capillary phenomenon, and a water passage sheet covering the outer circumference of the water passage, and a permeation water pipe with a tip cone for preventing ground liquefaction. We have developed a method for preventing ground liquefaction, which is characterized by burying in a vertical direction or an oblique direction with respect to the ground surface at appropriate intervals in the ground that is easily liquefied in the event of an earthquake.

The water pipe used in the above method is buried in the ground and serves as a passage for allowing groundwater to escape to the ground before the ground is liquefied in the event of an earthquake. The tip is made of a hard material such as metal or plastic. There is a tip cone formed in, and a large number of water inlets are provided in the rear of the cone, and it is not crushed in the ground where a water passage communicating with the water inlet is formed in the surface direction. A tubular body having both a degree of rigidity and elasticity, the water passage having a cross-sectional area large enough not to cause a capillary phenomenon, and a water-permeable sheet covering the outer periphery of the tube are provided. We have developed a permeated water cylinder with a tip cone for preventing the ground liquefaction.

Further, in the case where the ground is soft or has a void, a permeation water pipe with a tip cone has been developed as a permeation water pipe with a tip cone. Is long, 1
We have developed an axially connected product that is cut to about m.

Further, according to the present invention, there is provided a tip cone which is a passage for releasing groundwater to the ground before the ground is liquefied in the event of an earthquake, and has a tip cone formed of a hard substance such as metal or plastic at the tip. , A large number of water inlets are provided at the rear of the cone, and it has both rigidity and elasticity to the extent that it is not crushed in the ground where a water passage communicating with the water inlet is formed in the surface direction. A tubular body, the water passage having a cross-sectional area that is large enough not to cause capillary action, and a water permeable sheet that covers the outer circumference of the tube. When the water bottle is buried in the ground, (a) the outer side of the water-permeable sheet is covered with a protective tube, and (b) the permeation water tube with a tip cone covered with the protective tube is shaken with the tip cone first. Monken hammer machine, hydraulic pushing machine Or implanted by the driving machine,
A method for embedding a permeate water pipe with a tip cone for preventing ground liquefaction, characterized by inserting the hole into the ground by excavating with a drilling blade on the tip cone, and (c) inserting and then removing the protective cylinder. And as another burying method,
We have developed a method of digging a hole in the ground in advance and burying a permeation pipe with a tip cone in it.

In the present invention, the ground surface means
In addition to the general ground surface, it is used as a term that includes artificially formed cliffs, walls of tunnels and underground spaces, and the like. The water-permeable sheet is composed of a mesh, woven fabric, knitted fabric or non-woven fabric made of fiber, metal, plastic, chemical fiber or the like, and has a filtering effect.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the first aspect of the invention, as shown in FIGS. 8 and 12, for example, a plurality of permeation water pipes 1 with tip cones as shown in FIGS. It is achieved by embedding in the ground at intervals.
FIG. 12 is a partially cutaway sketch showing one example thereof, and FIG.
It is sectional drawing in the II-II line in FIG. In these figures, a plurality of permeation water pipes 1 with tip cones are buried regularly or randomly over a certain area, and a flowing water layer 31 is formed from a end portion 34 in contact with the ground surface 30 into a gutter or the like. It is provided so as to be connected to the drainage channel 33. It shows a state in which a pavement layer 32 is formed on the ground surface 30 so as to cover the running water layer 31. The detailed structure of the permeation water pipe 1 with a tip cone in these figures will be described in detail in the embodiment of the permeation water pipe 1 with a tip cone described below. As a result, the pore water generated in the ground due to the earthquake is ejected to the ground surface 30 through the permeable water passage cylinder 1 with the tip cone, and further through the water passage member 31 to the drain groove 3
It is discharged to 3. This prevents liquefaction of the ground.

1 and 2, FIG. 3 and FIG. 4, and FIG. 5 and FIG.
Shows an embodiment of the permeation water pipe 1 with a tip cone, which is the invention according to claim 2, and the permeation water pipe 1 with a tip cone is also the invention of claims 1, 6 and 7. Used. FIG. 1 and FIG. 2 show a first embodiment of the permeation water pipe 1 with a tip cone, in which a cylindrical body having a reinforcing body 7 inside is used as a water pipe for raising excess pore water at the time of an earthquake to the surface of the earth. It shows what was there.

FIG. 1 is a vertical sectional view thereof, and FIG. 2 is a sectional view taken along line AA in FIG. In these figures, 1 is a permeation water pipe with a tip cone, and 2 is a tip cone. The tip cone 2 is made of a hard material such as metal, plastic, or ceramics, and its shape is preferably a pointed cone or a pyramid such as a pyramid or a semi-spherical shape, and the rear end is , There is a rear end portion 3 having the largest diameter. However, depending on the soil quality, a disk or plate with a flat tip may be used.

A water pipe 4 is provided behind the tip cone, and the water pipe 4 is made of hard plastic or metal. And, it has a cylindrical shape, the cylinder has a large number of water inlets 5 communicating with the inside and the outside over the entire surface, and a water passage 6 is formed in connection with the water inlet 5 and this water passage 6 is It extends over the entire length in the axial direction of the water pipe 4 and opens at the rear end (right side in the figure), that is, where it comes into contact with the ground surface when it is buried. The water pipe 4 is a tubular body having both rigidity and elasticity to the extent that it is not crushed in the ground, and has a reinforcing body 7 toward the center. The water pipe 4 is connected to the tip cone, and the outer peripheral surface thereof is covered with a water permeable sheet 8.

The water permeable sheet 8 is also used in the tip cone 2
It is connected to. However, either one of the water pipe 4 and the water permeable sheet 8 may be connected to the tip cone 2,
When the water pipe 4 is connected to the tip cone 2,
The water-permeable sheet 8 may be connected to it. Further, on the rear surface of the tip cone 2, the permeation water pipe 1 with the tip cone is provided.
There is a hole into which a pipe-shaped or rod-shaped operation rod 11 used when inserting the rod is inserted. With the operation rod 11 inserted in this hole, the portion of the rod that is exposed on the ground surface is further driven into When the protection tube 9 is pulled out after the cone has been bitten into the ground, only the protection tube can be pulled out without the water passage tube rising up together. Further, the operation rod is inserted into the hole in the water pipe 4 when the permeation water pipe 1 with the tip cone is inserted into the hole previously drilled with the casing pipe, and the bending rod of the water pipe is bent and meandered. Prevent operation rod 1
When the casing pipe is pulled out by pushing the tip cone into the ground with 1, the permeation water pipe with the tip cone 1
Does not go up together.

FIGS. 3 and 4 show a second embodiment in which a plastic pipe is meandered and entangled with each other to form a water pipe for draining groundwater to the surface during an earthquake. Is a vertical sectional view thereof, and FIG. 4 is a BB sectional view in FIG. In these figures, 1 is a permeation water tube with a tip cone, and 2 is a tip cone, which is the same as in the first embodiment. A water passage tube 14 is provided behind the water passage tube 14 in which a plurality of plastic linear objects are meandered and intertwined with each other to form a tubular shape. Since the linear objects of the water pipe 14 are loosely entangled with each other, there are many voids, and the outer peripheral surface thereof has a large number of openings which serve as the water inlet 15. As shown in the figure, the water pipe 14 has a hollow central portion, so that a large hollow portion serves as a water passage to discharge groundwater. However, in the case where the hollow portion is thin or there is no hollow portion, the portions where the plastic linear objects meander and are intertwined with each other form the water passage.

The internal void portion extends meandering over the entire length and continuously extends to the rear end (right side in the figure), which forms the water passage 16. The water passage cylinder 14 is a cylindrical body having both rigidity and elasticity to the extent that it is not crushed in the ground. These water passages 16 have a large cross-sectional area that does not cause a capillary phenomenon, and groundwater is not pumped up except for an earthquake. And when the groundwater pressure rises due to an earthquake, it is large enough to allow enough groundwater to escape to the surface.

On the outer circumference of the water pipe 14, there is a water permeable sheet 8 having a particle size of about several microns or more that does not allow the passage of earth and sand, so that only water can pass through the water pipe 14 during normal times and earthquakes. Do not let dirt in. Therefore, the water passage 16 is not clogged with earth and sand, and even during an earthquake, pore water generated by vibration can be quickly drained to the ground surface before the ground is liquefied, and earth and sand will not be jetted to the ground surface. Normally, only water enters the water passage 14 through the water permeable sheet 8, but does not rise above the groundwater level. Further, an operation rod 11 penetrating the center of the permeation water cylinder 1 with a tip cone can be connected behind the tip cone 2. As a result, when the rear end of the operating rod is driven in, the tip cone bites into the ground, and when the protective cylinder is removed, it is possible to prevent the water pipe from rising up together. The water flow tube 14 in which the plastic linear objects used here meander and are intertwined with each other to form a tubular shape may be, in addition to the illustrated one, a linear object up to the center.

Next, FIGS. 5 and 6 show another embodiment in which a reinforcing cylinder made of plastic is used as the permeation water cylinder 1 with a tip cone for draining groundwater to the surface during an earthquake. 5 is a partially cutaway view thereof. This reinforcing cylinder is made up of four types of short cylinders having four different configurations, that is, a unit obtained by joining together the ones indicated by the leader lines (a), (b), (c), and (d). , That unit is repeatedly connected. Each structure of the four types of short cylinders in one unit is shown in FIG. 6, and the cross-sectional views taken along the leader lines (a), (b), (c) and (d) in FIG. 5 are shown. It is shown in correspondence with 6 (a), (b), (c), and (d).

In these figures, 1 is a permeation passage cylinder with a tip cone, 2 is a tip cone, and 3 is a rear end portion, which are the same as those described in the previous example. Reference numeral 24 is a water passage cylinder, and the cross section of each portion is made of a plastic reinforced cylinder body having four types of shapes as shown in FIG. Further, 25 is a water inlet, which is provided in a large number all around the water passage 24, and a water passage 26 is provided in communication with the water inlet 25. Reference numeral 27 is a reinforcing body for reinforcing the water pipe 24, and the water passage 26 is formed over the entire length so as not to prevent groundwater from being discharged to the ground. The water permeable sheet 8 is provided on the outer periphery of the water passage cylinder 24.

Further, in these Examples 1, 2 and 3, the rear end edge 3 which is the maximum outer shape of the tip cone 2 is shown in FIG.
As is clear from FIGS. 3 and 5, the water passages 4, 14,
In addition, it is larger than the maximum outer diameter of the water-permeable sheet 8 and has an important meaning. I mean,
As shown in FIG. 7, when the permeated water cylinder 1 with the tip cone is inserted into the hole opened in the ground, the permeated water cylinder 1 with the tip cone is shown in FIGS. 1 and 2 so as not to damage it. After inserting the protective cylinder 9 into the outer circumference of the permeation water passage cylinder 1 with a tip cone, it is inserted into a hole 10 which is dug in advance, or is advanced to a predetermined position on the ground while excavating with a tip cone. At this time, if the protective cylinder 9 is out of the rear end edge 3 of the tip cone 2, the protective cylinder 9 will come off due to friction with the inner wall of the hole 10, and the protective cylinder 9 will no longer fulfill its protective role.

FIG. 7 is a view showing a state in which the permeated water cylinder 1 with a tip cone shown in Examples 1 to 3 is advanced to a predetermined position on the ground, and the permeated water cylinder with a tip cone shown in the above example is shown. In order to prevent the damage to 1, the protective cylinder 9 is inserted into the outer periphery of the hole before entering the ground, and the water-permeable sheet is protected by its own weight or by applying a weight with a Monken hammer or the like, and a pre-drilled hole Insert into No. 10 or excavate with a tip cone to enter the ground at a predetermined position. . Therefore, the rear end edge 3 of the tip cone 2 still projects to the outside of the outer circumference of the protective cylinder 9 even when the protective cylinder 9 is inserted.

A digging blade 45 provided after inserting the permeation passage cylinder 1 with a tip cone into the hole 10 or on the tip cone 2.
After excavating to a specified depth while excavating by (7th
(See the figure), the protective tube 9 must be separated from the permeation water tube 1 with a tip cone and pulled out from the hole. For this reason, the protective cylinder 9 is reversely rotated or pulled upward to release the engagement between the both, but the protective cylinder 9 and the permeation water pipe 1 with the tip cone are provided.
It is the trailing edge 3 of the tip cone 2 which serves to prevent the and from rotating and picking up together. Tip cone 2
When the permeation water cylinder 1 with the tip cone rises a little, the rear edge 3 acts as a wedge that digs into the surrounding ground and prevents the permeation water cylinder 1 with the tip cone from rotating in the reverse direction or rising. As a result, the protective cylinder 9 is separated from the tip cone 2, and only the protective cylinder can be pulled out to the ground surface.

However, depending on the soil quality, the rear end edge 3 of the tip cone 2 cannot engage with the surrounding soil or does not play the role of a wedge even if it engages, and the permeation water pipe 1 with the tip cone rotates in the reverse direction or rises. May not be prevented. That is,
Even if only the protection cylinder 9 is rotated reversely or moved up and down, the permeation passage cylinder 1 with a tip cone also rotates reversely and moves up and down together, so that the protection cylinder 9 does not separate from the tip cone and only the protection cylinder 9 is removed. It may not be possible to extract it on the surface of the earth.

In the ground where such a case is expected, the tip cone 2 having anchors 40 and 50 as shown in FIGS. 9, 10 and 11 is used. First of all,
The one shown in FIG. 10 is used when the protection cylinder 9 and the tip cone 2 are connected by a screw 46, and the like, and when only the protection cylinder 9 is pulled out from the permeation water cylinder 1 with the tip cone, First, the screw connection between the protective cylinder 9 and the tip cone 2 must be released. Therefore, the protective cylinder 9 must be rotated in the reverse direction, that is, in the direction of arrow B in FIG. 10. However, depending on the condition of the ground, the permeation water cylinder 1 with the tip cone also rotates in the direction B along with this reverse rotation, and the connection is made. I can't solve it.

In order to release this screw connection, an anchor 40 is rotatably attached to the tip cone 2. This anchor 40 is attached to a recess 41 provided near the outer periphery 43 of the tip cone 2 so as to be retractable through a shaft 42. When the anchor 40 is retracted into the recess 41, that is, when the state shown by the dotted line is reached. In addition, a part thereof projects outside the outer circumference 43.

Therefore, in order to insert the permeate water pipe 1 with the tip cone covered by the protective pipe 9 into the hole 10 or to advance it to a predetermined depth by excavation, the permeate water pipe 1 with the tip cone is moved in the forward direction, that is, the arrow in FIG. When rotated in the A direction, the anchor 40 does not have a resistance force, and most of it enters the inside of the tip cone 2 while leaving a part thereof outside the outer circumference 43 of the tip cone, and in the opposite direction, that is, in FIG. When rotated in the direction of arrow B, as shown by the solid line, it largely jumps out from the outer circumference 43 of the tip cone and bites into the surrounding earth and sand, and resists reverse rotation and rise of the permeate water cylinder 1 with the tip cone. It is configured to demonstrate.

Since a part of the anchor protrudes from the recess 41 even when a part of the anchor is closed, when it is rotated in the reverse direction, it engages with the surrounding earth and sand so as to open outward. When it moves and opens a certain angle, it engages with the stopper 44 and does not open any further, and in that state, it is possible to prevent the reverse rotation and rise of the permeate water pipe 1 with the tip cone by digging into the surrounding soil and sand. Because there is.

This is because when the anchor 40 is partly closed, part of it protrudes outward from the recess 41, so that when it is reversely rotated, it engages with the surrounding earth and sand and opens outward. It swings like this, and when it opens a certain angle, it engages with the stopper 44 and does not open any further, and in that state it can bite into the surrounding earth and sand and prevent the reverse rotation and rise of the permeate water cylinder 1 with the tip cone. Because it is. In addition, 4 in FIG. 9 is a water pipe, and 8 is a water permeable sheet.

Further, in the case where the protection cylinder 9 and the tip cone 2 are engaged with each other by unevenness or other engagement by the known detachable engaging means 56, the protection cylinder 9 is removed from the tip cone 2. As the tip cone 2 for preventing the permeation water cylinder 1 with the tip cone from being pulled up when it is pulled out, it is possible to use a tip cone with an anchor 50 as shown in FIG. The anchor 50 is mounted on the shaft 5 with its tip facing upward in a recess 51 provided near the outer circumference 53 of the tip cone 2.
It is attached so that it can be retracted through 2 and when the permeated water cylinder 1 with a tip cone is made to enter the ground, a recess 5
1, the part is projected to the outside of the outer periphery 53 as shown by the dotted line, and most of the part is buried in the recess 51.

For this reason, when the permeation water pipe 1 with the tip cone is moved downward in FIG. 11 in order to make the permeation water pipe 1 with the tip cone covered by the protection pipe 9 reach a predetermined depth by excavation, the anchor 50 does not have resistance and most of it enters the inside of the tip cone 2 with a part outside the outer circumference 53 of the tip cone, and when the protective cylinder 9 is moved upward and pulled out, it is shown by a solid line. As described above, the outer cone 53 of the tip cone 2 is largely ejected until it comes into contact with the stopper 54, bites into the surrounding earth and sand, and exerts a resistance against the rise of the permeation water tube 1 with the tip cone. .

FIG. 8 shows a state in which the permeation water pipe 1 with a tip cone is embedded in the ground. In this state, the protective cylinder 9 is pulled out from the state of FIG. 7, and the permeation water cylinder 1 with the tip cone is left in the hole 10. The space formed between the permeation water tube 1 with a tip cone and the ground around it may be filled with sand, or may be left as it is. Then, the running water layer 31 is connected to the upper end of the permeation passage cylinder 1 with a tip cone to dig a groove on the ground surface or on the ground surface.
FIG. 3 shows a state in which the pavement layer 32 is formed and the pavement layer 32 is formed thereon. Further, the running water layer 31 is connected to a drainage channel 33 such as a gutter.

FIG. 12 makes it easier to understand this situation as a whole. A plurality of permeation water pipes 1 with tip cones are buried regularly or randomly over a certain area. The flowing water layer 31 is provided so as to be connected to a drainage channel such as the gutter 33 from the end portion in contact with the. Then, the pavement layer 32 is formed on the entire ground surface so as to cover the running water layer 31.
Are formed. However, this pavement layer may be omitted.

Because of this, when the underground pore water pressure rises due to an earthquake, the pore water flows from the water inlets 5, 15, 25 of the permeate water cylinder 1 with the tip cone to the water channels 6, 1, 25.
It drains to the surface through 6, 26. For this reason, the pore water pressure of the groundwater decreases, and the sediment does not erupt along with the groundwater to the surface of the ground due to a crack having a low ground strength. Thereby, liquefaction of the ground at the time of an earthquake can be prevented.

[0034]

According to the first aspect of the invention, the following effects can be obtained. 1. The liquefaction of the ground during an earthquake can be reliably prevented only by embedding a permeated water passage with a simple cone having a tip cone. 2. Since maintenance is not required after burying the permeation water tube with a cone at the tip, maintenance is easy, and there is no jet of earth and sand to the surface of the earth during an earthquake, and the ground that can reliably prevent liquefaction can be obtained.

According to the invention of claim 2, the following effects can be obtained. 1. The structure of the permeation water pipe with the cone at the tip is simple and easy to produce. 2. Since the structure of the permeation water pipe with the tip cone is a column with a sharp tip, it is easy to enter the ground. 3, the cross-sectional area of the water passage of the permeate water cylinder with a tip cone is large, there is no rise of groundwater due to the capillary phenomenon, it does not unnecessarily pump groundwater except during an earthquake, and it can drain groundwater in a short time during an earthquake, It is possible to reliably prevent liquefaction of the ground during an earthquake.

4. The permeation pipe with a cone is strong because it has a reinforcing body and is not crushed or bent even during an earthquake. 5. Because there is a water permeable sheet, sediment does not enter the water pipe and sediment is not discharged to the ground with groundwater. As a result, the ground does not collapse. 6. The permeation pipe with a tip cone is durable because it is entirely plastic or mostly plastic and only part is metal (corrosion of this part is not related to groundwater discharge during an earthquake).

According to the inventions of claims 3 and 4, the following effects can be obtained. 1. The permeable liquefaction tube with a tip cone, which has a shape that makes it easy to enter the ground, can be liquefied by a simple construction because it can be driven by its own weight or a driving machine vertically or diagonally to the ground surface at appropriate intervals. The ground which can prevent is obtained. 2. The permeate water pipe with a tip cone, which serves as a drainage channel for groundwater in the event of an earthquake, can be easily buried without damaging it when buried. 3. No special machine or device is required for embedding. 4. Since it is a simple construction method, there are few troubles and efficiency is good.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view with a part cut showing a first embodiment of a permeation water pipe with a tip cone of the present invention.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a vertical cross-sectional view with a part cut showing a second embodiment of the permeation water pipe with a cone of the present invention.

FIG. 4 is a sectional view taken along line BB in FIG.

FIG. 5 is a partially cut side view showing a third embodiment of the permeation water pipe with a tip cone of the present invention.

6 is a cross-sectional view at the position of each lead line in FIG.

FIG. 7 is a cross-sectional view in the ground when the permeation water-carrying cylinder with a tip cone of the present invention is covered with a protective cylinder and inserted into a hole dug in the ground in advance.

FIG. 8 shows a state after the protective tube is removed from the state of FIG. 7,
In other words, this shows a state in which the permeated water pipe with the tip cone of the present invention is buried underground.

FIG. 9 is a vertical cross-sectional view of one embodiment of a tip cone with anchors.

10 is a cross-sectional view taken along the line I-I in FIG.

FIG. 11 is a longitudinal sectional view of another embodiment of a tip cone provided with an anchor.

FIG. 12 shows the invention according to claim 1, and is a partially cutaway sketch of a state in which a plurality of permeation water pipes with tip cones are buried in the ground at appropriate intervals.

[Explanation of symbols]

 1 ... Permeable water pipe with tip cone 2 ... Tip cone 4, 14, 24 ... Water pipe 5, 15, 25 ... Water inlet 6, 16, 26 ... Water passage 8 ... Water-permeable sheet 9 ... Protective tube 31 ... Flowing water layer 33 ... Grooves 40, 50 ... Anchor

Claims (7)

[Claims] 1. A tip cone formed of a hard material such as metal or plastic at the tip, and a large number of water inlets are provided behind the cone, and the water is communicated with the water inlet to extend toward the ground surface. A tubular body having rigidity and elasticity to the extent that it is not crushed in the ground where the water passage is formed, and the water passage has a large cross-sectional area that does not cause a capillary phenomenon. A water-permeable cylinder and a water-permeable sheet that covers the outer circumference of the cylinder are installed on the ground surface at appropriate intervals in the ground that is easily liquefied in the event of an earthquake. A method for preventing ground liquefaction, characterized by being buried vertically or diagonally. 2. A tip cone that is buried in the ground and serves as a passage for releasing groundwater to the ground before the ground liquefies in the event of an earthquake, and has a tip made of a hard substance such as metal or plastic. There is a large number of water inlets in the rear of the cone, and the rigidity and elasticity not to be crushed in the ground where a water passage communicating with the water inlet is formed in the surface direction are provided. A liquefied ground, which is also a double-walled tubular body, in which the water passage has a cross-sectional area that is large enough not to cause capillary action and a water-permeable sheet that covers the outer circumference of the water passage. Permeate water cylinder with tip cone for prevention. 3. One or more swingable anchors are attached to the outer periphery of the tip cone, and the anchor does not have resistance when the tip cone is rotated in the forward direction, and the tip does not have a resistance force. Along the outer circumference of the cone, or most of it goes inside the tip cone leaving a part of it, and during reverse rotation,
The permeation water tube with a tip cone according to claim 2, wherein the tip cone has a structure that jumps out from the outer periphery of the tip cone to bite into the surrounding soil and exert resistance against reverse rotation and ascent. 4. One or more swingable anchors are attached to the outer periphery of the tip cone, and the anchor does not have resistance when the tip cone goes into the ground and the tip cone does not have resistance. Along the outer periphery of the tip cone, or most of it enters the inside of the tip cone and when pulling it out, it jumps out from the outer circumference of the tip cone and bites into the surrounding soil and resists reverse rotation and ascent. The permeation water pipe with a tip cone according to claim 2, which is configured to exhibit. 5. The permeation water tube with a tip cone according to claim 2, wherein the permeation water tube with a tip cone is a series of pieces cut into appropriate lengths. 6. A passage for releasing groundwater to the ground before the ground is liquefied in the event of an earthquake, and has a tip cone formed of a hard substance such as metal or plastic at the tip. A large number of water inlets are provided in the rear of the, and a tubular shape that has both rigidity and elasticity to the extent that it is not crushed in the ground that communicates with the water inlets and has a water passage in the surface direction. The body is a body, and the water passage has a large cross-sectional area that does not cause a capillary phenomenon, and a water passage sheet covering the outer periphery of the water passage is provided. When burying inside,
(A) The outer side of the water-permeable sheet is covered with a protective cylinder, and (b) the permeate water-permeable cylinder with a tip cone covered with the protective tube is struck with the tip cone first such as a vibrator, a Monken hammer machine, or a hydraulic pushing machine. Inserted into the ground by driving with an inserter or excavating with an excavating blade on the tip cone, (c)
A method for embedding a permeation passage cylinder with a tip cone for preventing ground liquefaction, characterized in that the protection cylinder is removed after insertion. 7. A cone that serves as a passage for releasing groundwater to the ground before the ground liquefies in the event of an earthquake, and has a tip cone formed of a hard substance such as metal or plastic at the tip. A large number of water inlets are provided in the rear of the, and a tubular shape that has both rigidity and elasticity to the extent that it is not crushed in the ground that communicates with the water inlets and has a water passage in the surface direction. The body is a body, and the water passage has a large cross-sectional area that does not cause a capillary phenomenon, and a water passage sheet covering the outer periphery of the water passage is provided. When burying inside,
(A) A hole that is the same as or larger than the maximum outer shape of the tip cone is dug vertically or obliquely to the ground surface,
(B) In the hole, the permeation passage cylinder with the tip cone is used as it is, or the outer side of the water transmission sheet is covered with a protection cylinder, and inserted by its own weight or by a driving machine. (C) After the insertion, the protection cylinder is present. A method for burying a permeate water pipe with a tip cone for preventing ground liquefaction, characterized in that the protective cylinder is removed.