JP7164748B1 - Casing for building sand piles - Google Patents

Abstract

[Problem] A casing for sand pile construction that can reduce the overall construction cost and reduce the environmental load by reducing the amount of embankment and surplus soil generated during construction and reducing the use of material sand for filling. I will provide a. [Solution] It penetrates into the ground D while being rotated, and is used when forming a sand pile K by compaction without vibration and noise by repeating discharge and hammering of the pile material S when pulling out. A sand pile construction casing 10 having a casing body 11, wherein the casing body 11 is provided with an excavation/compaction part 20 that is radially spanned across the tip opening and excavates and compacts the ground D. The compacting unit 20 has an excavating unit that excavates the ground D on the forward rotation direction side of the casing body 11 and has a compaction surface that compacts the ground on the reverse rotation direction side of the casing body 11 . [Selection drawing] Fig. 1

Description

TECHNICAL FIELD The present invention relates to a casing for forming sand piles used when forming compacted sand piles in the ground.

Patent Document 1 discloses a casing (hollow tube) for constructing sand piles of this type. The hollow pipe for constructing sand piles described in Patent Document 1 has inclined blades formed on the outer peripheral surface of the hollow pipe main body. Then, the hollow pipe is rotated forward to penetrate the ground to a predetermined depth while discharging the soil around the hollow pipe to the ground surface through the inclined blades. The sand pile is formed by successively repeating the discharge of the sand pile material and the driving back (repenetration) of the sand pile material at the time of pulling out.

JP 2018-76663 A

However, when creating a sand pile using the conventional hollow pipe for creating a sand pile, the soil discharged to the ground surface by the inclined blades rises in the surrounding ground, and the disposal cost of the raised soil and surplus soil is high. Occur. Furthermore, in recent years, the price of material sand used for the filling material tends to rise, so the cost of the entire construction increases.

Therefore, the present invention has been made to solve the above-mentioned problems, and reduces the construction cost as a whole by reducing the heaped soil and surplus soil generated during construction and reducing the use of material sand for filling. It is an object of the present invention to provide a sand pile construction casing capable of reducing the load on the environment and reducing the load on the environment.

The sand pile construction casing according to the aspect of the present invention penetrates into the ground while being rotated, and repeats ejection and hammering of the pile material when pulling out, thereby compacting the sand pile without vibration and noise to form a sand pile. A casing for constructing a sand pile having a casing body used when building a sand pile, wherein the casing body is radially spanned across a tip opening and the central portion protrudes outward toward the tip side A fixed excavation/compaction part for excavating/compacting the ground is provided, and the excavation/compaction part includes a top portion as the central portion located on the central axis of the tip opening of the casing body, and the top portion. and a plurality of slanted portions extending toward the distal end side of the casing body and having base ends thereof fixed at intervals. has an excavating blade as an excavating portion for excavating the ground on one edge side, and an excavating surface that stands upright with respect to the excavating surface of the ground is formed, and the plurality of inclined portions are rotated in the opposite direction of the casing body. A compaction surface for compacting the ground is formed on each side in a curved surface shape .

The sand pile construction casing according to another aspect of the present invention penetrates into the ground while being rotated, and repeats ejection and hammering of the pile material when pulling out, thereby compacting the sand pile without vibration and noise. A sand pile construction casing having a casing body used when constructing a sand pile, wherein the casing body discharges surrounding soil to the ground surface when the casing body is penetrated into the ground on the outer peripheral surface A spiral screw is provided, and the spiral screw includes a large-diameter spiral screw whose spiral width is large from the lowest stage to the middle stage of the tip of the casing body, and a small-diameter spiral screw whose spiral width is small from the middle stage to the upper stage. A slanted stepped portion is provided on the large-diameter spiral screw side of the boundary connecting portion between the large-diameter spiral screw and the small-diameter spiral screw, and the slanted stepped portion is a boundary. The sand pile is adjusted so that the amount of soil that is driven back into the ground is greater than the amount of soil that is discharged to the ground surface, and the sand pile is driven back while rotating the casing body in the opposite direction. The sand pile is formed by compacting the material and the soil driven back into the ground with the spiral screw having the different diameter.

The sand pile construction casing according to another aspect of the present invention penetrates into the ground while being rotated, and repeats ejection and hammering of the pile material when pulling out, thereby compacting the sand pile without vibration and noise. A sand pile construction casing having a casing main body used when constructing a sand pile, wherein the casing main body is radially spanned across a tip opening so that the central portion protrudes outward from the tip An excavating/compacting part that is fixed to the side and excavates/compacts the ground, and a spiral screw that discharges the surrounding soil to the ground surface when the casing body penetrates into the ground on the outer peripheral surface, The excavating/compacting part has a top part as the central part located on the center axis of the tip opening of the casing body, and a base end extending from the top part to the tip side of the casing body and fixed with a space therebetween. and a plurality of inclined portions formed radially, and on the forward rotation direction side of the casing body of the plurality of inclined portions, an excavating blade as an excavating portion for excavating the ground is provided on one edge side. An excavation surface is formed perpendicularly to the excavation surface of the ground, and a compaction surface for compacting the ground is formed in a curved surface shape on each of the plurality of inclined portions on the opposite rotation direction side of the casing body. The spiral screw has a large-diameter spiral screw with a large spiral width from the lowest stage to the middle stage at the tip of the casing body, and a small-diameter spiral screw with a small spiral width from the middle stage to the upper stage. wherein an inclined stepped portion is provided on the large-diameter spiral screw side of the boundary connecting portion between the large-diameter spiral screw and the small-diameter spiral screw, and the ground surface is separated from the inclined stepped portion The amount of soil that is driven back into the ground is adjusted to be larger than the amount of soil that is discharged to the ground, and when driving back while rotating the casing body in the opposite direction, the sand pile material and the ground are adjusted. The sand pile is formed by compacting the soil that has been hammered back into the pile with the spiral screw having the different diameter.

According to the present invention, it is possible to reduce the cost of the entire construction and reduce the environmental load by reducing the heaped soil and surplus soil generated during construction and reducing the use of sand material for filling. A construction casing can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is a perspective view which shows the construction apparatus for sand pile construction of 1st Embodiment of this invention. Fig. 3 is a perspective view of a sand pile construction casing used in the sand pile construction construction device; Fig. 3 is a side view of the sand pile construction casing; It is the figure which looked at the said casing for sand pile construction from the front end side. FIG. 4 is a side view of FIG. 3 rotated 90 degrees around the axis; It is a partial perspective view of the tip side of the said sand pile construction casing. It is a partial side view of the front end side of the said sand pile construction casing. It is a perspective view of the middle part of the said sand pile construction casing. It is explanatory drawing at the time of penetration of the said casing for sand pile creation. It is a figure which shows the rotation direction of the excavation / compaction part at the time of the said penetration. It is explanatory drawing at the time of pulling out the said casing for sand pile construction. It is a figure which shows the rotation direction of the excavation / compaction part at the time of said extraction. It is explanatory drawing at the time of driving back of the said casing for sand pile creation. It is a partial side view of the front end side of the casing for sand pile construction used for the construction apparatus for sand pile construction of 2nd Embodiment of this invention.

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a construction device for constructing sand piles according to a first embodiment of the present invention. FIG. 2 is a perspective view of a sand pile construction casing used in the construction device for sand pile construction. FIG. 3 is a side view of a sand pile construction casing. FIG. 4 is a view of the sand pile construction casing as viewed from the front end side. FIG. 5 is a side view of FIG. 3 turned 90 degrees around the axis. FIG. 6 is a partial perspective view of the tip side of the sand pile construction casing. FIG. 7 is a partial side view of the tip side of the sand pile construction casing. FIG. 8 is a perspective view of the middle portion of the sand pile construction casing. FIG. 9 is an explanatory view of the penetration of the sand pile construction casing. FIG. 10 is a diagram showing the direction of rotation of the excavation/compaction section during penetration. FIG. 11 is an explanatory view when the sand pile construction casing is pulled out. FIG. 12 is a diagram showing the direction of rotation of the excavating/compacting section during extraction. FIG. 13 is an explanatory view of the sand pile construction casing when it is hammered back.

As shown in FIG. 1, a construction apparatus 1 for constructing sand piles includes a construction machine main body 3 having a leader 2 erected at the front, and a pile material (medium) that moves up and down along the leader 2 by winding a wire 4. An elevating bucket 5 for conveying sand S as a stuffing material) and a cylindrical sand pile forming casing ( a hollow pipe) 10, a connecting pipe 8 connected to the forced lifting device 6 and the rotary drive device 7, a hopper 9 attached to the forced lifting device 6 and supplying sand S to the casing 10, and the hopper 9 A supply pipe 9b is provided between the discharge port 5b side and the connecting pipe 8, and supplies the sand S supplied into the hopper 9 to the casing 10 side by gravity.

As shown in FIG. 1, the hopper 9 is formed in the shape of a rectangular frame and attached to the forced lifting device 6. As shown in FIG. Sand S is supplied to the supply port 9a of the hopper 9 from the discharge port 5b of the lifting bucket 5. As shown in FIG. Further, the sand pile construction casing 10 is detachably attached to the connection portion 7a of the rotary drive device 7 via a connection holder 12. As shown in FIG. Reference numeral 5a in FIG. 1 indicates a supply port of the lifting bucket 5. The supply pipe 9b is attached so as to pass through the connecting pipe 8 obliquely, and supplies the sand S supplied from the hopper 9 into the connecting pipe 8 by gravity.

As shown in FIGS. 1 and 2, the sand pile construction casing 10 has a cylindrical casing body 11 made of metal. The sand (pile material: inner filling material) S is discharged and hammered back (re-penetration) is repeated sequentially, and the sand S and surplus soil (outer filling material) Dd are compacted without vibration and noise to expand the diameter. Sand pile K is constructed.

As shown in FIGS. 1 to 3 and 5, a connecting holder 12 for detachably connecting the casing body 11 to the rotary drive device 7 is provided at the proximal end portion 11a of the cylindrical casing body 11. there is A cylindrical mounting ring 13 having a diameter larger than that of the casing body 11 is fixed to the tip 11b of the casing body 11 having a cylindrical shape. The reason why the cylindrical mounting ring 13 is formed to have a diameter larger than that of the cylindrical casing body 11 is to reduce the friction of the casing body 11 and the earth pressure during penetration. Further, as shown in FIG. 5, the length (height) H of the casing body 11 is set to, for example, 100 cm (H=100 cm), and the outer diameter Q is set to, for example, 40 cm (Q=40 cm).

Further, as shown in FIGS. 3 to 5, high-pressure water or high-pressure air is supplied downward to the inner peripheral surface 11c of the cylindrical casing main body 11 at a position on the front end side and a position on the middle side separated by 180 degrees. An inner nozzle 14 for injecting high-pressure fluid (not shown) is attached. Further, the inner nozzles 14, 14 located in the upper middle stage are provided with supply ports 15 provided 180 degrees apart on the outer side of the base end portion 11a of the casing body 11, along the inner peripheral surface 11c of the casing body 11. A high-pressure fluid is supplied through each supply pipe 16 arranged so as to extend downward. The high-pressure fluid jetted from each of the inner nozzles 14 facilitates removal of the sand S when the casing body 11 is pulled out.

Furthermore, as shown in FIGS. 2 to 5, the attachment ring 13 fixed to the tip 11b of the cylindrical casing body 11 is radially spanned across the tip opening 11d of the casing body 11, and the ground D An excavating/compacting unit 20 for excavating/compacting is attached.

As shown in FIGS. 2, 6, and 7, the excavating/compacting section 20 includes a top portion 21 located on the central axis X of the tip opening 11d of the casing body 11, and a top portion 21 extending from the top portion 21 to the tip of the casing body 11. A plurality of (three in this embodiment) inclined portions 22 extending toward the 11b side and having base ends 22a fixed to the mounting ring 13 at equal intervals are formed radially.

As shown in FIGS. 2, 4, 6, and 10, the apex 21 is formed in a pyramidal shape with a triangular top surface (tip surface) 21a and six sided tip side surfaces (tip surface) 21b. . At the center of the top surface 21a, one excavation bit 21c protrudes in a hemispherical or angular shape. Further, a plurality of excavation bits 21c protrude in a hemispherical or angular shape from the tip side surface 21b forming the hexagonal pyramid.

As shown in FIGS. 2, 3, and 6, base ends 22a of the plurality of inclined portions 22, which are notched in an L-shape, are fixed by welding to a mounting ring 13 having a diameter larger than that of the casing body 11, respectively. there is As shown in FIGS. 6 and 10, on the forward rotation (right rotation) direction R side of the casing body 11 of each inclined portion 22 (the left edge side of the inclined portion 22 on the upper side in FIG. 10), An excavation surface 22c standing perpendicularly to the excavation surface of the ground D having an excavation blade 22b as an excavation portion for excavating the ground D on one edge side is formed. A plurality of excavation bits 22d are protruded along the excavation edge 22b from the excavation surface 22c at positions near the excavation edge 22b. Furthermore, as shown in FIGS. 6 and 12, each inclined portion 22 is located on the reverse rotation (counterclockwise rotation) direction L side of the casing body 11 (from the right side of the inclined portion 22 on the upper side in FIG. ), a compaction surface 22e for compacting the ground D is formed in a curved surface shape. As shown in FIG. 6, each inclined portion 22 has a distal side inclined surface 22f on the distal side and a proximal side inclined surface 22g on the proximal side.

Further, as shown in FIG. 7, the tip side surface 21b of the top portion 21 is inclined with respect to the central axis X of the casing main body 11 by, for example, 30 degrees (θa=30 degrees). Furthermore, each inclined portion 22 is inclined, for example, by 15 degrees (θ=15°) with respect to the central axis X of the casing body 11 . Also, the length (height) Ha from the tip of the inclined portion 22 to the mounting ring 13 is set to, for example, 70 cm (Ha=70 cm).

As shown in FIGS. 2, 5, and 9, the casing body 11 has an outer peripheral surface 11e with a spiral structure that discharges surrounding (around the casing) soil Dd to the ground surface Dh when the casing body 11 penetrates into the ground D. It has a screw 30 . The soil Dd discharged (discharged) to the ground surface Dh by the spiral screw 30 swells on the ground surface Dh around the construction site and becomes the surplus soil of the mounded soil. It can be disposed of by using it as a part of

As shown in FIGS. 5 and 8, the spiral screw 30 includes a large-diameter spiral screw 31 made of a metal plate and having a large spiral width E from the lowest stage to the middle stage of the tip of the casing body 11, and a spiral screw 31 from the middle stage to the upper stage. It is a different diameter spiral screw having a small width F and a small diameter spiral screw 32 made of a metal plate. An inclined stepped portion 34 is provided on the large-diameter spiral screw 31 side of the boundary connecting portion 33 between the large-diameter spiral screw 31 and the small-diameter spiral screw 32 . The sand pile K is constructed so that the amount of the soil Dd that is driven back into the ground is larger than the amount of the soil Dd that is discharged to the ground surface Dh across the inclined stepped portion 34 . be. As shown in FIG. 5, the outer diameter M of the large-diameter spiral screw 31 is set to, for example, 60 cm (M=60 cm), and the spiral width E is set to, for example, 10 cm (E=10 cm). The outer diameter N of the small-diameter spiral screw 32 is set to, for example, 50 cm (N=50 cm), and the spiral width F thereof is set to, for example, 5 cm (F=5 cm).

Next, sand pile construction is performed by a sand pile construction casing 10 having a spiral screw 30 with a different diameter that discharges the soil Dd around the casing to the ground surface Dh on the outer peripheral surface 11e used in the sand pile construction construction device 1 having the above configuration. The steps will be described in order with reference to FIGS. 9 to 13. FIG.

First, as shown in FIGS. 9 and 10, the casing main body 11 of the sand pile construction casing 10 is rotated in the forward rotation direction R via the forced lifting device 6 and the rotation drive device 7 to move the excavation/compaction section 20. The ground D is excavated by the excavation blade 22b and the excavation surface 22c, and the casing main body 11 is penetrated into the ground D to a predetermined depth. At this time, the spiral screw 30 discharges the soil Dd around the casing to the ground surface Dh. Discharged soil discharged from the soil Dd around the casing to the ground surface Dh by a small-diameter spiral screw 32 smaller in diameter than the large-diameter spiral screw 31 provided from the middle stage to the upper stage of the casing body 11 is spread from the lower stage to the upper stage side. The diameter can be greatly reduced compared to conventional casings provided with spiral screws.

Next, as shown in FIGS. 11 and 12, when the casing body 11 is rotated in the reverse rotation direction L through the forced lifting device 6 and the rotation driving device 7, the casing body 11 is pulled out by an appropriate length. Sand S as a filling material is discharged, and the soil Dd as an outer filling material discharged from around the outer casing of the casing body 11 to the ground surface Dh and the soil Dd around the casing are introduced into the ground D by a spiral screw 30. Drop in (pull in) each. At this time, the amount of discharged sand S and the amount of input soil Dd input from the outside of the casing body 11 are each dropped into the ground D by the same amount.

Next, as shown in FIG. 13, the casing main body 11 is rotated in the reverse rotation direction L through the forced lifting device 6 and the rotary drive device 7, and is beaten back by an appropriate length, and discharged from the casing main body 11. The sand S and the soil Dd dropped into the ground are compacted by the excavation/compaction part 20 and the spiral screw 30 to expand the diameter. At this time, the compaction surface 22e of the excavation/compaction section 20 and the large-diameter spiral screw 31 of the spiral screw 30 can efficiently compact and expand the diameter. In addition, since the large-diameter spiral screw 31 of the spiral screw 30 has a larger diameter than the small-diameter spiral screw 32, when cohesive soil, silt, etc. adhere to the outer peripheral surface 11e of the casing body 11, the effect of dropping the surrounding ground is reduced. The soil can be efficiently dropped without any trouble, and the sand pile K is formed by expanding and compacting the diameter by the expansion pressure at the time of hammering.

Next, the pulling out of the casing body 11 and the hammering back are sequentially repeated until the ground surface Dh is reached, thereby completing a sand pile K whose diameter is expanded and compacted as shown in FIG.

As described above, according to the sand pile construction construction device 1 of the first embodiment, the sand S is used as the inner filling material, and the soil Dd discharged to the ground surface Dh as the outer filling material thrown in from the outside of the casing body 11 of the casing 10, and the soil Dd already By constructing the sand pile K using the same amount of embankment soil and surplus soil Dd of a certain surrounding ground as the amount of sand S discharged, it is possible to reduce the embankment soil and surplus soil generated during construction, and to fill the pile. The use of material sand can be reduced, and the cost of the entire construction can be reduced.

In addition, if the sand pile K is created by adjusting the amount of the inner stuffing material put into the casing main body 11 and the outer stuffing material put into the surroundings of the casing, and the rotation speed of the casing, respectively, the heaped soil generated during construction can be reduced. By reducing the amount of surplus soil and the use of sand for filling materials, it is possible to reduce the environmental load during construction.

Further, adjustment is made so that the amount of soil Dd that is beaten back into the ground is greater than the amount of soil Dd that is discharged to the ground surface Dh across the inclined stepped portion 34 of the spiral screw 30 having a different diameter. By constructing the sand pile K by doing so, it is possible to further reduce the mounded soil and surplus soil generated during construction, and it is possible to further reduce the cost of the entire construction.

FIG. 14 is a partial side view of the tip side of a sand pile construction casing used in a sand pile construction construction device according to a second embodiment of the present invention.

In the sand pile construction casing 10 used in the sand pile construction construction device of the second embodiment, the tip side surface 21b of the top portion 21 of the excavation/compaction section 20 is inclined at an angle of 60 degrees with respect to the central axis X of the casing body 11, for example. (θc=60°), and each inclined portion 22 is inclined 30° (θb=30°) with respect to the central axis X of the casing main body 11, which is different from that of the first embodiment. Since the rest of the configuration is the same as that of the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted. Also, the length (height) Hb from the tip of the inclined portion 22 to the mounting ring 13 is set to, for example, 35 cm (Hb=35 cm).

In this second embodiment, the tip side surface 21b of the top portion 21 of the excavation/compaction portion 20 is inclined, for example, by 60 degrees with respect to the central axis X of the casing body 11, and each inclined portion 22 is inclined to the central axis X of the casing body 11. In contrast, by inclining by 30 degrees, for example, the same functions and effects as those of the first embodiment can be obtained.

According to the above embodiment, the inner nozzle for injecting the high-pressure fluid is provided on the inner peripheral surface of the casing main body, but the outer nozzle for injecting the high-pressure fluid may be provided on the outer peripheral surface of the casing main body.

Further, according to the above-described embodiment, the excavation/compaction portion is radially formed with three inclined portions that extend from the top portion toward the tip side of the casing body and are fixed to the mounting ring. The portion may be formed radially with two or four sloping portions extending from the top to the distal end of the casing body and secured to the mounting ring.

Furthermore, according to the above embodiment, instead of sand, heaped soil or surplus soil may be used as the filling material to be put into the casing body. When the embankment soil or surplus soil is used as the filling material, the cost of the entire construction can be further reduced. In addition, when the embankment soil or the surplus soil cannot be used as the filling material, the embankment soil or the surplus soil may be used after being reformed so that it can be used as the filling material.

REFERENCE SIGNS LIST 10 Sand pile construction casing 11 Cylindrical casing body 11b Tip 11d Tip opening 11e Peripheral surface 13 Cylindrical attachment ring 20 Excavation/compaction part 21 Top 21a Top face (tip face)
21b tip side (tip face)
21c excavation bit 22 inclined portion 22a proximal end 22b excavation blade (excavation portion)
22c excavation surface (excavation part)
22e Compaction surface 30 Different diameter spiral screw 31 Large diameter spiral screw 32 Small diameter spiral screw 33 Boundary connecting part 34 Inclined stepped part D Ground Dh Ground surface Dd Soil around the casing, embankment soil, surplus soil (outer filling material)
S sand (pile material: inner stuffing material)
K Sand pile X Central axis R Forward rotation direction (Forward rotation direction)
L Reverse rotation direction (reverse direction)
E, F Spiral width

Claims (7)

A sand pile with a casing body that is used to create a sand pile by penetrating into the ground while rotating and compacting it without vibration and noise by repeating the discharge and hammering of the pile material when pulling it out. A casing for construction,
The casing body includes an excavating/compacting section that is radially spanned across the tip opening and fixed to the tip side so that the central portion protrudes outward, and that excavates and compacts the ground,
The excavated/compacted portion has a top portion as the central portion located on the central axis of the tip opening of the casing body, and a base end extending from the top portion to the tip side of the casing body and fixed with a space therebetween. and a plurality of inclined portions formed radially,
On the positive rotation direction side of the casing main body of the plurality of inclined portions, there are formed excavation surfaces that stand perpendicularly to the excavation surface of the ground, each having an excavation blade as an excavation portion for excavating the ground on one edge side. is,
A sand pile construction casing , wherein a compaction surface for compacting the ground is formed in a curved surface shape on each of the plurality of inclined portions on the side of the casing main body in the reverse rotation direction. A sand pile construction casing according to claim 1 ,
A sand pile construction casing, wherein the base ends of the plurality of inclined portions are attached to the tip of the casing body and fixed to a mounting ring formed to have a diameter larger than that of the casing body. A sand pile construction casing according to claim 1 ,
A sand pile construction casing, wherein the apex is formed in a pyramidal shape, and a plurality of excavation bits are protruded in a hemispherical or angular shape from a distal end surface of the pyramidal shape. A sand pile with a casing body that is used to create a sand pile by penetrating into the ground while rotating and compacting it without vibration and noise by repeating the discharge and hammering of the pile material when pulling it out. A casing for construction,
The casing body has a spiral screw on the outer peripheral surface that discharges the surrounding soil to the ground surface when the casing body penetrates the ground,
The spiral screw has a large-diameter spiral screw with a large spiral width from the lowest stage to the middle stage of the tip of the casing body, and a small-diameter spiral screw with a small spiral width from the middle stage to the upper stage. is a screw,
An inclined stepped portion is provided on the side of the large-diameter spiral screw of the boundary connecting portion between the large-diameter spiral screw and the small-diameter spiral screw,
Adjusting so that the amount of soil that is thrown back into the ground is greater than the amount of soil that is discharged to the ground surface at the inclined stepped portion,
The sand pile is formed by compacting the sand pile material and the soil driven back into the ground with the spiral screw having a different diameter when driving back while rotating the casing body in reverse. Casing for building sand piles. A sand pile with a casing body that is used to create a sand pile by penetrating into the ground while rotating and compacting it without vibration and noise by repeating the discharge and hammering of the pile material when pulling it out. A casing for construction,
The casing body is fixed to the tip end side so that the casing body is radially spanned across the tip opening and the central portion protrudes outward, and an excavation and compaction section for excavating and compacting the ground, and an outer peripheral surface. a spiral screw that discharges surrounding soil to the ground surface when the casing body penetrates into the ground,
The excavated/compacted portion has a top portion as the central portion located on the central axis of the tip opening of the casing body, and a base end extending from the top portion to the tip side of the casing body and fixed with a space therebetween. and a plurality of inclined portions formed radially,
On the positive rotation direction side of the casing main body of the plurality of inclined portions, there are formed excavation surfaces that stand perpendicularly to the excavation surface of the ground, each having an excavation blade as an excavation portion for excavating the ground on one edge side. is,
A compaction surface for compacting the ground is formed in a curved surface shape on each of the plurality of inclined portions on the opposite rotation direction side of the casing body,
The spiral screw has a large-diameter spiral screw with a large spiral width from the lowest stage to the middle stage of the tip of the casing body, and a small-diameter spiral screw with a small spiral width from the middle stage to the upper stage. is a screw,
An inclined stepped portion is provided on the side of the large-diameter spiral screw of the boundary connecting portion between the large-diameter spiral screw and the small-diameter spiral screw,
Adjusting so that the amount of soil that is thrown back into the ground is greater than the amount of soil that is discharged to the ground surface at the inclined stepped portion,
The sand pile is formed by compacting the sand pile material and the soil driven back into the ground with the spiral screw having a different diameter when driving back while rotating the casing body in reverse. Casing for building sand piles. A sand pile construction casing according to claim 5 ,
A sand pile construction casing, wherein the base ends of the plurality of inclined portions are attached to the tip of the casing body and fixed to a mounting ring formed to have a diameter larger than that of the casing body. A sand pile construction casing according to claim 5 ,
A sand pile construction casing, wherein the apex is formed in a pyramidal shape, and a plurality of excavation bits are protruded in a hemispherical or angular shape from a distal end surface of the pyramidal shape.

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