JP3862217B2 - Hollow pipe for sand pile construction and rectangular sand pile construction method with angle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In particular, the present invention creates a sand pile having an angled rectangular cross section in the ground of a contaminated ground area by overlapping a short side and a tangent side or part of another adjacent sand pile, thereby providing continuous permeability in a circular arrangement. The present invention relates to a sand pile building hollow pipe and a rectangular sand pile building method capable of efficiently constructing a purification wall with low noise, low vibration, and efficiency.
[0002]
[Prior art]
There is a ground improvement pile construction method that improves the ground by placing sand piles in soft ground such as loose sandy ground and highly watery viscous ground. As this ground improvement pile construction method, for example, after penetrating the hollow tube to a predetermined depth, the process of pulling out the hollow tube to an appropriate length and the process of re-penetrating the hollow pipe are sequentially brought to the ground surface. Repeatedly, in the compacted sand pile construction method to create a compacted sand pile in soft ground, or in the above method, the hollow pipe re-penetration process is omitted and the sand is discharged into the ground while pulling out the hollow tube There is a sand pile construction method that creates sand piles in soft ground. In these construction methods, in order to improve the soft ground entirely, a construction method with a replacement rate of 100% for the original ground of the sand pile in which the sand pile is formed in close contact with the improved region substantially without gaps, There is a method of constructing sand piles in a continuous wall shape only in a part.
[0003]
On the other hand, volatile organic compounds such as trichlorethylene, which are used in large quantities in the cleaning process of semiconductor manufacturing factories and the like, may contaminate the soil or groundwater due to leakage, etc. In this case, it becomes an obstacle to reuse of the factory site. Or the use of groundwater is limited. As a method for purifying such contaminated soil or contaminated groundwater, there is a groundwater purification method using a continuous underground water purification wall. This groundwater purification wall is a metal system in a groove formed by trench excavation, for example, in the direction of blocking the flow of contaminated groundwater when the flow of contaminated groundwater generated from the pollution source is formed in one direction with an aquifer. A mixture of reducing material and sand is installed. And according to this underground continuous groundwater purification wall, when the contaminated groundwater passes through the groundwater purification wall, a pollution-free treatment by a reduction reaction is performed.
[0004]
This method for purifying groundwater is to purify by installing a groundwater purification wall in the natural flow of groundwater, but there is a problem that the purification efficiency is poor and the purification period is prolonged. As a solution to this, water injection wells distributed in the contaminated ground area and ground water containing pollutants disposed in the center of the contaminated ground area are pumped up, and the pumped ground water is returned to the water injection well. A forced purification method in which a permeable purification wall is provided between the pumping equipment and the water injection well and so as to surround the pumping equipment in a circular shape has been studied.
[0005]
[Problems to be solved by the invention]
However, in the conventional ground improvement pile construction method, the circularly arranged permeability purification wall is to create a sand pile having a circular cross section or a rectangular cross section by partially overlapping the short side of another adjacent sand pile. However, like the sand pile shown by the code | symbol a of FIG. 10 and the code | symbol c of FIG. 11, if the part d which overlaps with an adjacent sand pile is thin, it can produce the continuous wall-like sand pile which has uniform thickness. On the other hand, if the portion e overlapping with the adjacent sand pile is thick like the sand pile indicated by the symbol b in FIG. 10, there is a problem that the number of sand piles to be driven increases and the construction efficiency is deteriorated.
[0006]
Furthermore, the method of creating a sand pile having a rectangular cross section is a method of creating a sand pile having a cross sectional shape corresponding to a rectangular rectangular tube formed at the tip of the hollow tube. The hollow tube can be penetrated by operating a vibro hammer. However, when a hollow tube is driven using a vibro hammer, vibrations and noise are generated, which causes problems such as requiring environmental measures.
[0007]
Therefore, the object of the present invention is to form a circular pile with an angled rectangular cross section in the ground of a contaminated ground area, for example, by overlapping the short side and the adjacent side or part of another adjacent sand pile. An object of the present invention is to provide a sand pile building hollow pipe and a rectangular sand pile building method capable of efficiently constructing a continuous permeable purification wall with low noise, low vibration, and efficiency.
[0008]
[Means for Solving the Problems]
In such a situation, the present inventors have intensively studied. As a result, if a hollow tube having a specific tip shape is constructed by a reciprocating rotation operation, vibration and noise can be suppressed as much as possible, and an angled abbreviation can be obtained. The present inventors have found that a sand pile having a rectangular cross section can be formed, and that a high-quality circular arrangement of continuous wall-shaped sand piles and a permeable purification wall can be efficiently formed, and the present invention has been completed.
[0009]
That is, the present invention (1) includes a cylindrical hollow tube into which a sand pile material is charged, and a pair of protrusions attached to the left and right sides of the tip of the hollow tube, and the outer periphery of the protrusion The cross-sectional shape of the projection is substantially triangular, and the attachment position of the projection is an angle between the pair of projections of 100 degrees or more and less than 180 degrees. An object of the present invention is to provide a sand pile building hollow tube for building a sand pile having an angled rectangular cross section in the ground. In addition, the present invention (2) includes two steps of a reciprocating rotation operation step at the predetermined depth position and a sand pile material discharging step by drawing after the hollow pipe for sand pile formation to penetrate to a predetermined depth. A sand pile construction method is provided in which a sand pile having an angled rectangular cross section is created in the ground by sequentially repeating to the ground surface. Moreover, this invention (3) provides the said sand pile construction method which performs a re-penetration process after the discharge process of the sand pile material by the said extraction. In addition, the present invention (4), after penetrating the sand pile forming hollow tube to a predetermined depth, simultaneously performing reciprocating rotation operation and discharging sand pile material while pulling out to the ground surface, The present invention provides a sand pile construction method for creating a cross-sectional sand pile. Further, the present invention (5) includes a step of simultaneously performing a reciprocating rotation operation and discharging the sand pile material while pulling out to the predetermined height after penetrating the sand pile forming hollow pipe to a predetermined depth, After reaching the height, the sand pile material is created by repeating the two steps of stopping sand pile material discharge and re-penetrating to the surface of the ground to form a sand pile with an angled rectangular cross section in the ground. Is. Moreover, this invention (6) is the continuous wall-like sand of circular arrangement | positioning by overlapping the short side of the sand pile of the said rectangular cross section with an angle | corner, and the short side of another adjacent sand pile, or a part or part. The sand pile construction method for creating a pile is provided. Moreover, this invention (7) provides the said sand pile construction method whose continuous wall-like sand pile of the said circular arrangement | positioning is a permeable purification | cleaning wall which purifies the ground of a contaminated ground area.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, a sand pile building hollow pipe and a sand pile building method using the same in the embodiment of the present invention will be described with reference to FIGS. 1 is a plan view of a hollow pipe for sand pile formation of this example, FIG. 2 is a front view of a lower portion of the hollow pipe for sand pile formation of this example, and FIG. 3 is a plan view of a reciprocating rotation device of the hollow pipe FIG. 4 is a front view showing a part of the hollow tube reciprocating rotation device in a broken state, FIG. 5 is a schematic view of the sand pile forming device equipped with the sand pipe forming hollow tube of this example, and FIG. FIG. 7 is a view for explaining an angled rectangular cross-sectional shape of a sand pile formed using the hollow tube of FIG. 1 and FIG. 2, and FIG. 7 is sand formed using a hollow tube in which the installation angle of a pair of protrusions is changed. FIG. 8 is a plan view schematically showing an underground purification structure using a circular permeable purification wall of this example, and FIG. 9 is an AA line in FIG. Sectional drawing in the steady state of the purification | cleaning seen along is shown, respectively.
[0011]
1 and 2, a sand pile building hollow tube 1 includes a cylindrical hollow tube 1a into which a sand pile material is charged, and a pair of protrusions attached to the left and right sides of the tip of the hollow tube 1a. 1b. The protrusion 1b has a substrate 122 having the same curvature fixed to the bolt holes 2 formed in the cylindrical hollow tube 1a at a predetermined pitch p by the bolt 4, and a predetermined height H fixed to the substrate 122. The outer peripheral cross-sectional shape is a substantially triangular shape, and the protrusion main body 121 is rounded at the tip. The top and bottom surfaces of the protrusion main body are sealed with a top plate 123 and a bottom plate 124, respectively. The protrusion 1b has a plane angle where the attachment position to the hollow tube 1a is formed between the pair of protrusions 1b, that is, a line (long axis) connecting the tip of one protrusion 1b and the central axis of the hollow tube 1 ) And a line (long axis) connecting the tip of the other protrusion 1b and the central axis of the hollow tube 1 is a plane angle α on the side forming a narrow angle of 100 ° or more and less than 180 ° It is arranged at the position. In this example, it is about 150 degrees (the other side angle is 210 degrees). If this angle α is 180 degrees, the cross-sectional shape of the sand pile created by the turning operation becomes a substantially rectangular shape, and a continuous wall-like sand pile with a uniform thickness with a circular arrangement cannot be created or is uniform. If an attempt is made to make a thicker one, the construction efficiency will deteriorate. On the other hand, if the angle α is too small, only a small circle can be created when trying to create a continuous wall-shaped sand pile with a circular arrangement of uniform thickness. The arrangement angle of the pair of protrusions 1b shown in FIG. 1 is set a little small so that it can be easily understood that the protrusions 1b are at a specific angle.
[0012]
The method for attaching the protrusion 1b to the cylindrical hollow tube 1a includes the above-described method of welding a pair of protrusions 1b to the cylindrical tube 1a, and one of the pair of protrusions 1b is bolted. The other is a method by welding, a method of attaching an outer tube so as to surround the cylindrical hollow tube 1a in plan view, and the like. When the outer tube is attached, the cross-sectional shape of the outer periphery of the outer tube is cut off by a predetermined length on the opposite corners of the rhomboid short axis, and the opposite corners on the long axis A rounded form may be used. The angle between the pair of protrusions 1b is in the vicinity of a predetermined angle by appropriately selecting the bolt hole 2 in the case of this example or when one of the pair of protrusions 1b is bolt tightening and the other is welding. It is preferable in that it can be easily installed. Moreover, the roundness 64 at the tip of the protruding portion main body 121 may or may not be provided. However, when the roundness is provided, the smaller the rounded radius, the more preferable is that a long-axis-shaped sand pile is formed. is there. Further, the height H of the protrusion main body 121 is a length corresponding to the drawing stroke, that is, the length of the sand pile by one drawing, and is appropriately determined depending on the soil condition and the purpose of improvement. Further, on both the left and right sides of the inner peripheral surface of the tip of the cylindrical hollow tube 1a, excavation bits 5 projecting downward from the tip are installed to facilitate penetration of the sand pile forming hollow tube 1 into the ground. ing. In the sand pile forming hollow tube 1 of this example, the shape of the hollow tube 1a is not limited to the above-described cylindrical shape, and a polygonal shape such as a quadrangle, an elliptical shape, and an indefinite shape can also be used.
[0013]
The sand pile building hollow tube 1 of this example is for building a sand pile having an angled rectangular cross section in the ground by a reciprocating rotation operation. The hollow pipe reciprocating rotation device for sand pile formation is not particularly limited, and examples thereof include a mechanical rotation device that uses an electric motor and gears, and a hydraulic rotation device. Examples of the hydraulic rotating device include those shown in FIGS. 3 and 4. That is, the hollow tube reciprocating device 10 reciprocally rotates the hollow tube 1a using a pair of hydraulic cylinders 15 attached so as to sandwich the hollow tube 1a from both sides from the opposite side of the leader 12 (FIG. 3). It is a device that penetrates and pulls out while cutting the friction with the ground.
[0014]
The hollow tube reciprocating rotation device 10 is fixed to a side of the leader guide portion 13 opposite to the leader 12 of the leader guide portion 13 that moves up and down along the leader 12, and is restricted by the reciprocating movement of the hollow tube 1a. The fixed portion 16 and the tip of the piston rod 52 that are not attached are attached to the piston rod shaft support portions 17 attached to both side surfaces of the hollow tube 1a, and the cylinder portion 51 is attached to the cylinder shaft support portion 61 of the fixed portion 16 A pair of hydraulic cylinders 15 are provided so as to sandwich 1a from the side opposite to the leader 12 and to be positioned at the center position in the vertical direction of the leader guide portion 13.
[0015]
The fixed portion 16 is fixed to a pair of upper and lower hollow disk members 18 fixed to the leader guide portion 13 and an end portion 111 of the pair of hollow disk members 18 on the side opposite to the leader 12. The whole has a substantially U-shape in a side view. The hollow disk member 18 is an intermediate member for integrally fixing the vertical member 62 to the leader guide portion 13. For this reason, the hollow disk member 18 has an inner diameter larger than the outer diameter of the hollow tube 1a, and a bearing 19 is interposed between the hollow tube member 18a and the hollow tube member 1a. It is not regulated. The vertical member 6 is substantially U-shaped, and a vertical axis 55 fixed to the cylinder portion 51 of the hydraulic cylinder is pivotally supported in the horizontal direction at the center in the vertical direction of the left and right side surfaces of the vertical member main body 621. A cylinder shaft support 61 is provided.
[0016]
The hydraulic cylinder 15 includes a cylinder part 51 and a piston rod 52, and is attached to the cylinder part 51 so as to be rotatable in a horizontal direction on a cylinder shaft support part 61 as a fixed part. In the state where the hydraulic cylinder 15 is attached to the hollow tube 1 and the fixed portion 16, the hydraulic cylinder 15 maintains a horizontal position, and when the hydraulic cylinder 15 is positioned at the center position in the vertical direction of the leader guide portion 13, external force is applied to the leader 12. This is preferable in that transmission is performed efficiently.
[0017]
Further, as shown in FIG. 5, the hopper 22 and the forced elevating device 21 located above the hollow tube reciprocating device 10 are integrally coupled to the fixed portion 16 of the hollow tube reciprocating device 10. . For this reason, the hopper 22, the forced elevating / lowering device 21 and the hollow tube reciprocating / rotating device 10 are similarly lowered by the descending activation of the forced elevating device 21, and similarly raised by the ascending activation. The hopper 22 is for making it easy to throw sand pile material into the hollow tube 1 and a known one is used. Further, the forcible elevating device 21 is not particularly limited as long as the reaction force from the leader 12 can be obtained at the time of penetration and withdrawal, for example, by rack and pinion, by chain and sprocket, by towing a wire rope And so on.
[0018]
Next, a method for creating a sand pile having an angled rectangular cross section in the ground using the sand pile building hollow pipe of this example will be described. First, when the forced elevating device 21 is lowered, the hollow tube reciprocating rotation device 10 is activated, and the sand pile forming hollow tube 1 is pushed and pulled within a predetermined rotation range, and reciprocally rotates to a predetermined depth. Intruded until. Penetration efficiency is improved by rotating the sand pile building hollow tube 1 in the penetration step. When the sand pile building hollow tube 1 is driven to a predetermined depth, the process proceeds to a reciprocating rotation operation process at the predetermined depth position. The rotation range may be the same as the rotation range at the time of penetration, and is an angle twice as large as the swing angle indicated by β in FIG. That is, it is rotated in the direction of the arrow Y from the position where the long axis is on the line AB, is stopped at the position where the long axis is on the line CB, and is further rotated in the direction of the arrow X. By stopping at a position where the long axis is on line -B and repeating this as necessary, an extraction trace of an angled rectangular cross section indicated by the oblique lines in FIG. 6A is obtained after extraction. By appropriately selecting the rotation range, the cross-sectional shape of the extraction trace becomes close to an angled rectangle, and the sand pile can be efficiently created without waste in a circular arrangement of continuous walls. Moreover, if the reciprocating rotation operation is not performed, it is only possible to leave a trace of a shape corresponding to the shape of the cylindrical hollow tube having the protruding portion after the drawing, and the sand is formed into a continuous wall shape in a circular arrangement. Even if the pile is constructed, it does not become a wall with a uniform thickness, or if it tries to obtain a wall with a uniform thickness, the number of hits of the sand pile increases and the construction efficiency deteriorates.
[0019]
Then, after the reciprocating rotation operation process, the process proceeds to a sand pile material discharging process by drawing. The drawing stroke is the height H of the protrusion 1b of the sand pile building hollow tube 1 or less. If the length H is pulled out, the extracted trace surely forms an angled rectangular cross section, and the shape after the sand pile material is discharged also forms an angled rectangular cross section 6a. The sand pile material is not particularly limited, and examples thereof include sand, crushed stone, gravel, other sand-like granular materials, and those in which a metal-based reducing material is mixed. Sand containing a metal-based reducing material is applied to a permeable purification wall constructed for the purpose of purifying, for example, groundwater contaminated with organic volatile compounds. In the case of pulling out, the reciprocating rotation operation is not particularly necessary. After discharging the sand pile material by pulling out, the reciprocating rotation operation process and the sand pile material discharging process by pulling are sequentially performed again at the position after the pulling, and thereafter the same operation is sequentially repeated until the ground surface. As another example, after the sand pile material is discharged to the drawing trace, a re-penetration process may be performed and compaction may be performed. As another example, after the sand pile building hollow pipe has penetrated to a predetermined depth, the sand pile material is discharged while reciprocating while pulling out to the ground surface. A pile may be created. Further, at this time, after the hollow pipe for sand pile formation is penetrated to a predetermined depth, the reciprocating rotation operation and the discharging of the sand pile material are simultaneously performed while being pulled out to a predetermined height, and after reaching the predetermined height. The two steps of stopping the sand pile material discharge and re-penetrating may be sequentially repeated up to the ground surface. In the case of this re-penetration, it is preferable that the sand pile forming hollow tube 1 is rotated in the same rotation range in that a compacted sand pile closer to the rectangular section 6a with an angle is formed. .
[0020]
Moreover, the rectangular sand pile construction method of this invention makes the at least short side 61a (both ends) of the sand pile of the angled rectangular cross section 6a overlap the short side and the adjacent side or a part of the other adjacent sand pile. A circular walled continuous sand pile or a permeable purification wall 7a is created. In the present invention, since both side ends 61a of the rectangular rectangular cross section 6a are rounded, it is preferable that the portion f is overlapped in that a continuous wall-shaped sand pile having a uniform thickness can be constructed. is there. 7 shows a case where the angle α formed between the pair of protrusions 1b is about 120 degrees. In this case, compared with FIG. 6, a circular arrangement (actually a hexagonal arrangement) is formed. It can be seen that the diameter of the continuous wall-like sand pile 7b is small. Therefore, when creating a wall shape with a large circular arrangement, the angle α may be set to an angle close to 180 degrees.
[0021]
According to the sand pile forming hollow tube 1 of this example and the sand pile forming method using the same, vibration and noise can be suppressed as much as possible, and a sand pile having an angled rectangular cross section 6a can be formed. It is possible to efficiently produce a continuous wall-shaped sand pile 7a having a circular arrangement of quality. Furthermore, in the sand pile forming apparatus provided with the conventional rotation driving means, a rotation driving apparatus such as an electric motor or a swivel apparatus is attached. These facilities have a complicated mechanism and are large-scale, which contributes to an increase in the cost of the apparatus. However, if the hollow pipe for sand pile formation of this invention is used, since a rotational drive apparatus and a swivel apparatus can be abbreviate | omitted, this sand pile formation apparatus can be made simple and the cost reduced.
[0022]
Next, a utilization example of the circularly permeable purification wall constructed by the sand pile construction method of the present invention will be described with reference to FIGS. That is, FIG.8 and FIG.9 is a figure explaining the underground purification method using such a permeable purification wall. First, the contaminated ground area 30 to be purified is surrounded by the impermeable wall 20, and the contaminated ground area 30 is impermeable. Next, a pumping facility 50 such as a pumping well is disposed at a depth reaching the impervious layer 80 at the center of the contaminated ground area 30. The water injection well 40 is disposed outside the contaminated portion 100 and inside the impermeable wall 20 at a depth that reaches the water-impermeable layer 80 at the same distance from the pumping equipment 50 and at a position corresponding to four equal intervals of 90 degrees. The Next, the permeable purification wall 60 is disposed between the pumping equipment 50 and the water injection well 40 and at a depth reaching the water-impermeable layer 80 in a circular continuous wall shape surrounding the pumping equipment 50. Next, a ground pipe 510 for supplying the contaminated groundwater from the pumping facility 50 to the water injection well 40 is attached. The underground purification structure 200 before purification in which the respective facilities are arranged in this way has a cross-sectional form as shown in FIG.
[0023]
Next, the pumping equipment 50 is operated. That is, the contaminated groundwater is pumped up by the pumping equipment 50, the pumped-up contaminated groundwater is returned to the ground through the water injection well 40, the returned groundwater is treated by the permeable purification wall 60, and the treated water is further treated by the pumping equipment 50. Inhale and repeat this to form a forced groundwater circulation system. After the predetermined time has elapsed, as shown in FIG. 9, the groundwater level decreases to the lower part of the contaminated portion 100 at the position of the pumping facility 50, and exhibits a parabolic shape that gradually increases as the distance from the pumping facility 50 increases. This state is a steady state of purification. In the process of lowering the groundwater level and the subsequent steady state, the pollutant contained in the contaminated groundwater passing through the permeable purification wall 60 is rendered harmless by a reaction such as decomposition or adsorption with a metal-based reducing material. Such treatment of contaminated groundwater is repeatedly performed until the purification target value of the contaminated groundwater can be achieved. In such an underground purification method, the contaminated groundwater passes through the circular permeable purification wall 60 evenly, so that the metal-based reducing material in the permeable purification wall acts effectively and the purification efficiency is increased.
[0024]
【The invention's effect】
According to the construction method using the sand pile forming hollow tube of the present invention, vibration and noise can be suppressed as much as possible, and a sand pile having an angled rectangular cross section can be formed, and a continuous wall having a high quality circular arrangement. The sand pile or the permeable purification wall can be efficiently created. In addition, the sand pile building hollow tube has a relatively simple structure and requires a hollow tube reciprocating rotation device, but it is possible to omit a rotational drive device and a swivel device that are more expensive than the device. The cost of the creation device can be reduced.
[Brief description of the drawings]
FIG. 1 is a plan view of a hollow tube for sand pile formation according to the present example.
FIG. 2 is a front view of the lower part of the hollow pipe for sand pile formation of this example.
FIG. 3 is a plan view of a hollow tube reciprocating rotation device.
FIG. 4 is a front view of the hollow tube reciprocating device with a part thereof broken away.
FIG. 5 is a schematic view of a sand pile forming apparatus equipped with the sand pile forming hollow pipe of this example.
6 is a diagram for explaining an angled rectangular cross-sectional shape of a sand pile formed using the hollow tube of FIGS. 1 and 2. FIG.
FIG. 7 is a diagram for explaining an angled rectangular cross-sectional shape of a sand pile formed using a hollow tube with a different installation angle of a pair of protrusions.
FIG. 8 is a plan view schematically showing an underground purification structure using a circularly arranged permeable purification wall of this example.
9 is a sectional view in a steady state of purification as seen along line AA in FIG.
FIG. 10 is a diagram for explaining a circular continuous wall constructed by a conventional sand pile construction method.
FIG. 11 is a diagram for explaining a circular continuous wall constructed by another conventional sand pile construction method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sand pile formation hollow pipe 1a Cylindrical hollow pipe 1b Protrusion part 5 Excavation bit 6a Angled rectangular cross section 7a, 7b Circular wall continuous sand pile 10 Hollow pipe reciprocating rotation device 12 Leader 13 Leader guide Part 15 Hydraulic cylinder 16 Fixed part 17 Piston rod shaft part 18 Hollow disk member 20 Water shielding wall 21 Forced lifting device 22 Hopper 30 Contaminated ground area 40 Water injection well 50 Pumping equipment 51 Cylinder part 52 Piston rod 60 Permeability purification wall 61 Cylinder Shaft support 64 Roundness 121 Projection body 122 Substrate 200 Ground purification structure

Claims (7)

A cylindrical hollow tube into which sand pile material is charged, and a pair of protrusions attached to the left and right sides of the tip of the hollow tube, and the cross-sectional shape of the outer periphery of the protrusion is substantially triangular. The projecting portion is provided at a position where a plane angle formed between the pair of projecting portions is an angle of 100 degrees or more and less than 180 degrees, and an angled rectangular cross section is formed in the ground by a reciprocating rotation operation. A hollow pipe for sand pile construction characterized by constructing a sand pile. After penetrating the sand pile forming hollow pipe according to claim 1 to a predetermined depth, the two steps of the reciprocating rotation operation step at the predetermined depth position and the sand pile material discharging step by pulling are sequentially repeated to the ground surface. A sand pile construction method, characterized in that a sand pile having an angled rectangular cross section is created in the ground. The sand pile construction method according to claim 2, wherein a re-penetration step is performed after the step of discharging the sand pile material by the drawing. After penetrating the hollow pipe for sand pile formation according to claim 1 to a predetermined depth, a reciprocating rotation operation and discharging of the sand pile material are simultaneously performed while pulling out to the ground surface, and a sand pile having an angled rectangular cross section is formed in the ground. A sand pile construction method characterized by construction. A step of simultaneously performing a reciprocating rotation operation and discharging sand pile material while pulling out to a predetermined height after penetrating the sand pile forming hollow pipe according to claim 1 to a predetermined depth, and after reaching the predetermined height The sand pile construction method is characterized in that the sand pile material discharge is stopped and the re-penetration process is sequentially repeated until the ground surface, and a sand pile having an angled rectangular cross section is created in the ground. A continuous wall-shaped sand pile having a circular arrangement is formed by overlapping at least a short side of a sand pile having an angled rectangular cross-section with a short side of another adjacent sand pile and a side or a part thereof. The sand pile construction method of any one of Claims 2-5. The sand pile construction method according to claim 6, wherein the continuous wall-shaped sand pile having a circular arrangement is a permeable purification wall for purifying the ground in a contaminated ground area.

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