JP2013039054A - Screw pile, method for driving the same, and construction method of weed-proof sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw pile hard to pull out while facilitating driving work, a method for driving the screw pile, and a construction method of a weed-proof sheet using the screw pile.SOLUTION: The spiral screw 1 includes a pile body part 2 formed by winding a wire material 1a of φ6 mm in spiral shape with a helix angle θ of 45°, and a winding seat 3 formed at the winding end portion, and having a circular arc part 5 with a central angle of 270° and a linear part 6 extending in the diametrical direction. The tip of the pile body part 2 is cut at an inclined face to form a cut surface 4 facing the center axis A side of the pile, and a cutting edge that bites into a driving surface is formed at the edge of the cut surface 4. The winding seat part 3 of the screw pile 1 is mounted to an electric impact driver 7 through a chuck 10, and a vertical load and a striking force in a rotating direction are applied to the screw pile 1 to drive the screw pile 1 from the top of the weed-proof sheet 30 laid on the ground G. When driving is completed, the winding seat part 3 is engaged with the uneven shape of the weed-proof sheet 30 to make it hard for the screw pile 1 to rotate in a pull-out direction.

Description

  The present invention relates to a spiral pile and a method for placing the same. Moreover, it is related with the construction method of the weed prevention sheet | seat which lays a weed prevention sheet | seat on the ground and fixes this to a ground with a spiral pile.

  When the roadside or trackside ground is not paved, there is a problem that weeds that grow on the ground deteriorate the landscape and hinder the passage of vehicles. In order to solve this problem and maintain the landscape and ensure traffic safety, weeding work must be carried out regularly. Therefore, in order to eliminate the need for such weeding work, it has been proposed to lay a light shielding and waterproof sheet material (weedproof sheet) on the ground. Patent Document 1 discloses this type of herbicidal sheet.

  In Patent Document 1, after arranging a weed prevention sheet (embossed sheet) on the ground to be weeded, the anchor pin is driven into the ground from above the weed prevention sheet at a predetermined interval, thereby fixing the weed prevention sheet to the ground. To do. As the anchor pin, a straight pile having a bent head is used. In addition, since the weedproof sheet is an embossed sheet having irregularities, the sheet end can be prevented from being turned up by folding the sheet end and embedding it in the soil.

JP 2006-177122 A

  When fixing a weedproof sheet by driving a pile as in Patent Document 1, it is difficult to pull out the pile by increasing the pull-out load of the pile in order to reliably prevent the weedproof sheet from lifting and turning up. There is a need to. However, in the case of a straight pile, it is necessary to increase the length of the pile in order to increase the pull-out load, and the place where it can be placed is limited. In addition, when placing a pile on the ground, it is common to strike the pile head by hitting it manually. However, such a placement operation has a large work load. In addition, when a straight pile is manually driven, it is difficult to stably apply a vertical load, and workability at the time of driving is not good. Furthermore, there is also a problem that the pile is deformed or tilted due to the load direction being shifted at the time of placing.

  SUMMARY OF THE INVENTION In view of these points, an object of the present invention is to provide a helical pile that is capable of obtaining a sufficient pull-out load even if the length is short and that is difficult to be pulled out, a driving method thereof, and a weedproofing An object of the present invention is to propose a method for constructing a weedproof sheet that can perform the work of fixing the sheet to the ground so as not to be lifted or turned over with a small work load.

  In order to solve the above-mentioned problems, the helical pile of the present invention, the driving method thereof, and the construction method of the weed prevention sheet are characterized as follows.

That is, the spiral pile of the present invention is
A pile body portion in which a wire is spirally wound with a twist angle of 45 degrees or more;
A winding seat portion formed at the winding end portion of the wire rod at the base end portion of the pile body portion;
The tip of the pile main body has a shape obtained by cutting the wire with a single plane,
The winding seat includes an arc portion in which the wire is wound in an arc shape with a central angle of 270 degrees or more centered on the central axis of the pile main body portion, and a radial center side of the arc portion from one end of the arc portion It is characterized in that it comprises a straight line portion that linearly extends the wire rod bent to a position beyond the central axis.

  With such a configuration, the spiral pile of the present invention can be driven into the ground easily by rotating around the central axis while applying a vertical load to the pile main body. Further, after driving, the pulling load in the vertical direction is large, so that it cannot be pulled out from the ground easily. Therefore, the object can be firmly fixed to the ground. The present inventor made various types of spiral piles, and performed a placement test on the test soil. As a result, when the orientation of the wire at the tip of the pile and the inclination between the ground and the ground is 45 degrees or more, the pile can be driven into the test soil without deforming the wire, and workability at the time of placing is also good. I have confirmed. In addition, when the wire rod at the tip of the pile body is cut at a single plane and the cutting edge is formed at the tip of the pile body, it is easy to bite into the placement surface, reducing the resistance during placement and placing. It has been confirmed that the sheet material laid on the surface can be penetrated. Therefore, in order to suppress the deformation of the pile main body due to the load at the time of driving and enable easy driving, the above configuration is adopted.

  In addition, the spiral pile of the present invention forms, at the base end portion of the pile main body portion, an arc portion concentric with the pile main body portion, and a winding seat portion including a linear portion passing on the central axis of the pile main body portion. Therefore, a stable vertical load can be applied to the central axis of the pile through this winding seat. Moreover, the rotational force without center shift can be applied to a pile main-body part by applying a rotational force via a linear part. Furthermore, since the arc portion is provided in an angle range of 270 degrees or more, the inclination of the pile body portion and the shift of the load position can be suppressed by guiding the arc portion. Therefore, the workability at the time of placing is good, and the deformation of the wire rod and the inclination of the pile due to the center deviation of the vertical load and the rotational force hardly occur. Furthermore, since the winding seat has a shape that allows easy mounting of a pile coaxially with the output shaft of an electric tool such as an electric impact driver, the work load can be greatly reduced by using the electric tool.

  In this invention, the cut surface of the said wire formed in the front-end | tip of the said pile main-body part is a surface inclined to the side of the said central axis in the said pile main-body part with respect to the axial direction of the said wire in the said front-end | tip. Is desirable. If comprised in this way, the blade edge formed in the front-end | tip of a pile main-body part with a cut surface will become a shape inclined largely with respect to the placing surface of a pile. Therefore, the tip of the pile main body can be easily bited into the placing surface.

  Moreover, in this invention, the cross-sectional shape of the said wire is a circular cross section with a diameter of 6 mm or more, the outer diameter of the said pile main-body part and the said winding seat part is 42 mm, The length of the said central-axis direction of the said pile main-body part Is preferably 200 mm or more. The present inventor made various types of helical piles having different dimensions such as the diameter of the wire, the outer diameter of the pile main body and the winding seat, the length of the pile main body, etc. The workability at the time of installation, deformation, and the pull-out load of the spiral pile after placement were confirmed. As a result, it has been determined that it is desirable to adopt the dimensions as described above in order to obtain a sufficiently large pull-out load without deforming the helical pile during placement.

Next, the present invention is a method for placing the spiral pile as described above,
At the tip of the rechargeable electric impact driver, a chuck for detachably mounting the winding seat part is provided,
The chuck can be mounted with the spiral pile so that the rotation axis of the electric impact driver and the center axis of the pile main body portion are in agreement.
The spiral pile is driven by transmitting the output rotation of the electric impact driver to the spiral pile via the chuck.

  As described above, the present invention allows the spiral pile to be detachably attached to the electric impact driver and can be driven by the output rotation of the electric impact driver. , Work load can be greatly reduced. In particular, since the rechargeable electric impact driver does not require the power cord to be routed, the workability is extremely good. In addition, a chuck that can attach and detach a winding seat that can stably apply vertical load and rotational force to the helical pile is provided, so that the helical pile can be mounted coaxially with the rotation axis of the electric impact driver. Workability is extremely good, and stable driving work can be performed. In addition, defects such as deformation and inclination of the helical pile are less likely to occur.

  In the present invention, the chuck includes a clamp member for sandwiching the linear portion, a lock mechanism for locking the clamp member in a state of sandwiching the linear portion, and the linear portion is sandwiched between the clamp members. A guide portion that guides the arc portion in a state, the locking mechanism prevents the winding seat portion from being detached from the chuck, and the guide portion restricts the inclination of the pile main body portion with respect to the rotation axis. In the state, the helical pile can be driven by the electric impact driver. If it does in this way, stable vertical load and rotational force can be added, without attaching a hand to a spiral pile, and vertical load can be applied with both hands. Therefore, workability is very good. In addition, it is easy to attach and detach the winding seat portion to the chuck.

Next, the construction method of the sheet for grass protection of the present invention is as follows:
Laying an embossed weedproof sheet with a predetermined uneven pattern on the ground,
The above-mentioned helical pile is fixed on the ground by placing the above-mentioned helical pile on the ground at a predetermined interval from the top of the above-mentioned grass-proofing sheet by the above-described helical pile driving method,
Each spiral pile penetrates the grass for preventing grass and is placed so that each wire forming the arc portion and the straight portion is fitted in a gap between the convex portions in the concavo-convex pattern. It is characterized by being.

  According to the present invention, since the weedproof sheet is fixed to the ground by the spiral pile having a large pulling load, the weedproof sheet can be fixed to the ground so as not to be lifted or turned up. In addition, this spiral pile has good workability at the time of placing, and deformation and inclination of the pile are less likely to occur. By performing the placing work using an electric impact driver, the work load is greatly reduced and the workability is extremely high in that it is not necessary to route the power cord. Furthermore, when the placement is completed, the wire forming each part of the spiral pile winding seat part is formed in a state of being fitted in the gaps between the convex parts of the concavo-convex pattern. It is difficult to rotate, and it is difficult to rotate the spiral pile in the pulling direction. Therefore, there is also an advantage that the spiral pile is difficult to come off.

  According to the present invention, the tip of the spiral pile is easy to bite into the placement surface, and the sheet material can be penetrated, so that there is little resistance during placement and the placement operation is easy. Moreover, while being able to apply the stable vertical load to a winding seat part, the concentric rotational force with a pile main-body part can be added easily. Therefore, workability at the time of placing is good, and deformation and inclination are hardly generated. And the spiral pile after placement has a large pull-out load and cannot be pulled out from the ground easily. Therefore, an object such as a grass protection sheet can be firmly fixed to the ground. Furthermore, since the driving work can be performed using an electric tool such as an electric impact driver, the work load can be greatly reduced as compared with the conventional driving work by human power.

It is a side view of the spiral pile which concerns on embodiment of this invention. It is the top view which looked at the spiral pile of FIG. 1 from the winding seat part side. It is a side view which shows the state which attached the spiral pile to the electric impact driver via the chuck | zipper. It is the side view and top view of a chuck | zipper. It is a longitudinal cross-sectional view (XX sectional drawing of FIG.4 (b), YY sectional drawing of FIG.4 (b)) of a chuck | zipper. It is explanatory drawing which shows operation | movement of a clamp member. It is explanatory drawing which shows the cross-sectional structure of the ground which constructed the sheet | seat for grass prevention. It is a top view which shows the fixing location of the spiral pile in the sheet | seat for grass prevention after construction.

  Below, with reference to drawings, the embodiment of the spiral pile to which this invention is applied, and its placement method is described.

(Configuration of spiral pile)
FIG. 1 is a side view of a spiral pile according to an embodiment of the present invention, and FIG. 2 is a plan view of the spiral pile as seen from the winding seat portion side. The spiral pile 1 includes a pile main body portion 2 in which a wire rod 1 a having a circular cross section of φ6 mm is spirally wound, and a winding seat portion 3 formed at a base end portion of the pile main body portion 2. As a raw material of the wire 1a, steel materials, such as S45C, can be used, for example. The spiral shape of the pile body 2 is set so that the outer diameter L1 is 42 mm and the twist angle θ is 45 degrees. Moreover, length L2 from the base end part of the pile main-body part 2 to a front-end | tip is 200 mm, and is set to the length by which the wire 1a is wound about 3 times.

  The tip of the pile body 2 has a shape obtained by obliquely cutting the wire 1a on a plane. In the present embodiment, the cut surface 4 is an upward surface facing the central axis A side of the pile main body portion 2, and the lower edge portion of the cut surface 4 forms an acute angle with the outer peripheral surface of the wire 1a. It intersects as if to make. For this reason, a downward sharp edge along the edge of the cut surface 4 is formed at the tip of the pile body 2. By forming such a blade edge, when the helical pile 1 is driven, the tip of the pile can be easily bited into the driving surface. Therefore, there is little resistance added to the pile main-body part 2, it becomes possible to drive with small force, and a deformation | transformation of the wire 1a can be suppressed. The direction of the cut surface 4 is not limited to the direction illustrated in FIG. 1, but is inclined toward the central axis A with respect to the axial direction (tangential direction) of the wire 1 a at the tip of the pile body 2. It is desirable to make the cut surface 4 into the cut surface 4. If it does in this way, the angle with respect to the placement surface of the blade edge | tip formed in the edge of the cut surface 4 can be made into an angle larger than 45 degree | times which is the twist angle of the wire 1a. Therefore, the cut surface 4 can be easily bited into the placement surface.

  The wire 1a forming the pile main body 2 forms the winding seat 3 after being bent in the horizontal direction at the base end (spiral end portion) of the pile main body 2. Starting from this bending position, the winding seat 3 extends the wire 1a in an arc shape with a central angle of 270 degrees centered on the central axis A, and then bends the wire 1a toward the radial center side of the arc to obtain the central axis The shape extends to a position exceeding A. That is, the winding seat part 3 includes a circular arc part 5 concentric with the pile main body part 2 and a straight line part 6 that extends from one end of the circular arc part 5 to the front of the opposite part of the circular arc part 5 through the central axis A. I have.

  In determining the configuration of the spiral pile 1, the inventor creates various test bodies having different thicknesses of the wire 1a, the outer diameter L1 of the pile body 2, the pile length L2, the twist angle θ, and the like. These were used to perform placement tests on various test soils. And confirmation tests, such as workability | operativity at the time of placement, the presence or absence of a deformation | transformation of a test body, and the drawing-out load after placement, were done. Moreover, the test was done using the straight straight pile as a comparative example. As a result, it was difficult to screw the wire 1a into the ground in the test body in which the inclination of the wire 1a at the tip of the spiral pile 1 was less than 45 degrees with respect to the ground to be placed. Moreover, in the test body using the wire 1a thinner than 6 mm, bending of the wire 1a occurred and it was difficult to place. Furthermore, bending of the wire 1a occurred in the test body in which the outer diameter of the pile main body 2 was larger than 42 mm.

  As for the pulling load, the pulling load increases when the pile is lengthened. However, when it exceeds 200 mm, the effect of improving the pulling load is reduced. On the other hand, when the pile is less than 200 mm, the pulling load is greatly reduced. Moreover, it was confirmed that the helical pile had a significantly larger pulling load than the straight pile even if its length was about half that of the straight pile. For example, in two types of test soils of gravel + silt and clay, it was confirmed that the pulling load of the spiral pile 1 was 40 kgf or more. Further, the pulling-out load at the time of placing on the actual ground (hard soil, soft soil) was about 30 kgf for hard soil and about 20 kgf for soft soil. On the other hand, the pull-out load of the double pile (400 mm) straight pile was about 7 kgf even in hard soil. In the present embodiment, the shape of the helical pile 1 is determined as described above based on the above results.

  Further, the present inventor has studied a shape that can apply a vertical load and a rotational force (a striking force in the rotational direction) in a stable state when the helical pile 1 is placed, and is less likely to cause a shift or inclination of the load position. . In addition, assuming that the spiral pile 1 is driven using an electric impact driver 7 (see FIG. 3) described later, the mounting performance to the electric impact driver 7 and the driving work using the electric impact driver 7 are performed. Considered the workability by. As a result, the shape of the winding seat 3 was selected. That is, the winding seat part 3 is formed concentrically with the pile main body part 2, and since the straight part 6 passes through the central axis A, a stable vertical load can be applied to the central axis A. Further, by applying a rotational force via the straight portion 6, it is possible to apply a rotational force without center deviation to the pile main body portion 2. Furthermore, since the arc portion 5 is provided over an angle range of 270 degrees, the inclination of the pile main body portion 2 and the shift of the load position can be suppressed by guiding the arc portion 5. Therefore, workability at the time of placing is good, and deformation of the wire rod and inclination of the pile due to the vertical shift and the center deviation of the rotational force are less likely to occur. The central angle of the arc portion 5 may be larger than 270 degrees.

(Lacing pile driving method)
FIG. 3 is a side view showing a state in which the spiral pile 1 is attached to the electric impact driver 7 via a chuck. In this embodiment, when the spiral pile 1 is placed on a placement surface such as the ground, an electric tool such as a rechargeable electric impact driver 7 is used. As shown in FIG. 3, the output shaft 8 of the electric impact driver 7 is provided with a tool attachment portion 9 for attaching various tip tools. An insertion hole 9a for inserting a shaft body (shank) provided at the rear end of the tip tool is provided at the tip of the tool mounting portion 9, and the shaft body is tightened in the insertion hole 9a. (Not shown) is provided. By appropriately operating the tool attachment portion 9, the tip tool can be attached and detached by switching between a state in which the shaft body is tightened with the claw portion to prevent the tip tool from coming off and a state in which the claw portion is loosened.

  4 is a side view and a plan view of the chuck, FIG. 4 (a) is a side view, and FIG. 4 (b) is a plan view. 5 is a longitudinal sectional view of the chuck (FIG. 5 (a) is an XX sectional view of FIG. 4 (b), and FIG. 5 (b) is a YY sectional view of FIG. 4 (b)). The chuck 10 includes a substantially cylindrical chuck main body 12 having a shank 11 for fixing the chuck 10 to the tool mounting portion 9 at one end. The shank 11 protrudes coaxially from the end face on one end side of the chuck body 12. The outer peripheral surface of the shank 11 has a shape obtained by partially cutting a cylindrical outer peripheral surface into a flat shape. The planar portion (planar portion) is formed at a position corresponding to the arrangement of the claw portions in the tool attachment portion 9, and each planar portion extends in the axial direction of the shank 11. In the present embodiment, three flat portions are formed at an angular pitch of 120 degrees in the circumferential direction. Thus, by making the shank 11 have a substantially triangular cross-sectional shape, the chuck 10 can be mounted on the tool mounting portion 9 in a non-rotatable manner.

  On the other end side of the chuck main body 12, a large diameter portion 13 having a large diameter is formed. A pile mounting for fitting the winding seat portion 3 of the spiral pile 1 on the end surface of the large diameter portion 13 is provided. A portion 14 is formed. The pile mounting portion 14 includes an annular guide groove 15 (guide portion) centered on the central axis B of the chuck body portion 12 and a linear guide groove 16 extending in the diameter direction of the guide groove 15. The guide grooves 15 and 16 are formed to have dimensions that allow the arc portion 5 of the winding seat portion 3 to be mounted in the guide groove 15 and the linear portion 6 to be mounted in the guide groove 16. That is, the groove width and depth of the guide grooves 15 and 16 correspond to the diameter of the wire 1 a, and the outer diameter of the guide groove 15 corresponds to the outer diameter of the winding seat portion 3.

  The chuck 10 is provided with a clamp mechanism and a lock mechanism described below for preventing the winding seat 3 from coming off when the winding seat 3 is mounted on the pile mounting portion 14. That is, a linear clamp installation groove 17 orthogonal to the guide groove 16 is provided on the end surface of the large diameter portion 13. The clamp installation groove 17 intersects the guide groove 16 at the position of the central axis B of the chuck main body 12 and is cut at a predetermined depth in the axial direction of the chuck main body 12. Both ends of the clamp installation groove 17 are connected to the guide groove 15 in the vicinity of the end face of the large-diameter portion 13, and in the portion from the upper portion of the large-diameter portion 13 to the lower half of the chuck body portion 12 located above the large-diameter portion 13, Open to the outer peripheral surface. A cylindrical cylinder 18 (lock mechanism) is mounted on the outer peripheral side of the chuck body 12 so as to cover the opening portion of the clamp installation groove 17. A pair of clamp members 19 and 20 are installed in the clamp installation groove 17 so as to be symmetric with respect to the central axis B of the chuck body 12. The clamp members 19 and 20 are swingably supported by support shafts 19 a and 20 a that extend in a direction orthogonal to the groove direction of the clamp installation groove 17. Further, sandwiching surfaces 19b and 20b for sandwiching the wire 1a (straight line portion 6) mounted in the guide groove 16 from both sides are formed at the lower ends of the clamp members 19 and 20.

  FIG. 6 is an explanatory view showing the operation of the clamp member. As shown in FIG. 6B, when the cylinder 18 is raised to the upper end of the chuck body 12, both ends of the clamp installation groove 17 are opened, and the clamp members 19 and 20 have a diameter larger than the outer peripheral surface of the chuck body 12. It can project outward in the direction. Coil springs 21 having both ends fixed to the clamp members 19 and 20 are installed at positions above the support shafts 19a and 20a in the clamp members 19 and 20. Since the clamp members 19 and 20 are urged by the coil spring 21, when the cylinder 18 rises, the lower ends of the clamp members 19 and 20 swing radially outward. Thereby, the clearance gap between the clamping surfaces 19b and 20b spreads, and the clamping state of the wire 1a (straight line part 6) by the clamp members 19 and 20 is cancelled | released. That is, when the cylinder 18 is raised, the unlocking state of the clamp mechanism is formed, and the wire 1 a can be attached to and detached from the guide groove 16.

  On the other hand, as shown in FIG. 6A, when the cylinder 18 is lowered to a position where it abuts against the large diameter portion 13, both ends of the clamp installation groove 17 are closed by the cylinder 18 and radially outward of the clamp members 19 and 20. Protrusions are regulated. Accordingly, the lower ends of the clamp members 19 and 20 swing radially inward against the urging force of the coil spring 21, and the sandwiching surfaces 19b and 20b sandwich the wire 1a (straight line portion 6) from both sides. That is, in this state, it becomes impossible to remove the wire 1a (straight line portion 6) from between the sandwiching surfaces 19b and 20b, and the clamp mechanism is locked. Thus, the cylinder 18 constitutes a lock mechanism for switching the clamp mechanism between the locked state and the unlocked state.

  As described above, in this embodiment, by using the chuck 10, the spiral pile 1 can be detachably attached to the electric impact driver 7. Here, as described above, since the guide groove 15 is concentric with the chuck main body 12, the center axis B of the chuck main body 12 and the center of the spiral pile 1 when the winding seat 3 is mounted on the pile mounting portion 14. Axis A matches. In other words, when the spiral pile 1 is attached to the electric impact driver 7 via the chuck 10, the spiral pile 1 is brought into a state where the rotation axis C of the output shaft 8 of the electric impact driver 7 and the central axis A of the spiral pile 1 are matched. Can be installed. At this time, the straight portion 6 passing through the central axis A of the spiral pile 1 is not only fitted in the guide groove 16 but also the arc portion 5 on the outer peripheral side is fitted and guided in the guide groove 15. Therefore, the sense of unity between the chuck 10 and the spiral pile 1 is enhanced. Further, the clamp members 19 and 20 and the cylinder 18 prevent the spiral pile 1 from dropping off and the mounting position from being displaced. Accordingly, it is possible to stably apply a vertical load and a rotational force (a striking force in the rotational direction) with no center shift to the spiral pile 1 from the electric impact driver 7 side. At this time, it is not necessary to support one hand with the spiral pile 1, and a vertical load can be applied with both hands. Therefore, workability at the time of placing is good, and deformation or inclination of the spiral pile 1 is difficult to occur.

  As described above, in the placement work using the rechargeable electric impact driver 7, the work load can be greatly reduced as compared with the conventional placement work by human power. Furthermore, since it is not necessary to route the power cord, workability is extremely good.

(Method of constructing grass protection sheet)
Next, the construction method of the weed prevention sheet | seat using the spiral pile 1 to which this invention is applied is demonstrated, referring FIG. 7, FIG. FIG. 7 is an explanatory view showing the cross-sectional configuration of the ground on which the weedproof sheet is constructed, and FIG. 8 is a plan view showing the fixing location of the helical pile 1 in the weedproof sheet after construction. The weedproof sheet 30 is an embossed sheet in which a regular uneven pattern is formed, and is waterproof, weatherproof, strong, light-shielding and lightweight, which is suitable for preventing the growth of weeds and the like permanently installed outdoors. It has sex. Although the raw material of the sheet | seat 30 for grass prevention is not specifically limited, For example, synthetic resins, such as a high density polyethylene, can be used.

  The weedproof sheet 30 is formed with convex portions 31 having a shape in which the tip of a substantially quadrangular pyramid is cut and rounded in a staggered manner, and the convex portions 31 are turned upside down between adjacent convex portions 31. A recessed portion 32 having the shape is formed. Thus, since the convex part 31 and the recessed part 32 are reverse shapes and are arrange | positioned alternately, if the front and back are reversed, the convex part 31 and the recessed part 32 will be replaced, and it has the structure which can be used without the distinction of the front and back. Further, the grass protection sheet 30 has flexibility as a whole and can be laid along the uneven ground G. On the other hand, a person or heavy object passes through the ground laid on the ground. Also, the protrusion 31 and the recess 32 are strong enough to maintain the shape without being crushed.

  As shown in FIG. 7, in this embodiment, the weedproof sheet 30 is laid on the ground G, and the helical piles 1 are driven at regular intervals from above to fix the weedproof sheet 30 to the ground. . As shown in FIG. 8, each spiral pile 1 after placement has the winding seat portion 3 engaged with the uneven shape on the surface of the grass protection sheet 30. That is, the shape of the winding seat portion 3 is set so that the wire 1a forming the arc portion 5 and the straight portion 6 can pass through the concave portion 32 and fit into the gap between the convex portions 31. Has been. As described above, when the winding seat portion 3 is formed in a state where the winding seat portion 3 is fitted in the embossed gap, it is difficult to apply a force to the winding seat portion 3 when a person or an object moves on the grass protection sheet 30. . Moreover, when the linear part 6 is in the state fitted in the clearance gap between the convex parts 31, it is difficult to rotate the winding seat part 3, and it is difficult to rotate the spiral pile 1 in the removal direction. Therefore, the spiral pile 1 after placing is difficult to come off, and the curling and lifting of the grass protection sheet 30 can be effectively suppressed.

  The inventor conducted a test for placing the helical pile 1 on the ground G on which the grass protection sheet 30 was laid using the electric impact driver 7 and performed a confirmation test for placing property. As a result, the spiral pile 1 of the present embodiment has a configuration that easily penetrates into the placing surface as described above, and therefore can easily penetrate the weedproof sheet 30 and problems such as deformation of the spiral pile 1. It was confirmed that the sheet could be placed vertically without causing a high pulling load, and the grass protection sheet 30 could be firmly fixed. In addition, when driving with the electric impact driver 7, the vertical pile and the striking force in the rotating direction are applied to the chuck 10 until it penetrates the weed prevention sheet 30, and the spiral pile 1 is used for the weed prevention. After passing through the sheet 30, in order to prevent the weed protection sheet 30 from being lifted as the spiral pile 1 enters the ground G while rotating, the placement is performed while pressing the grass protection sheet 30 against the ground G. The knowledge that it is desirable to do is obtained.

  As described above, the spiral pile 1 can obtain a sufficient pulling load even if the length is much shorter than the conventional straight pile. Therefore, it is possible to construct the weedproof sheet 30 by using the spiral pile 1 even on the ground where the depth at which the conventional straight pile can be driven cannot be secured.

DESCRIPTION OF SYMBOLS 1 Spiral pile 1a Wire 2 Pile main-body part 3 Winding seat part 4 Cutting surface 5 Arc part 6 Linear part 7 Electric impact driver 8 Output shaft 9 Tool attachment part 9a Insertion hole 10 Chuck 11 Shank 12 Chuck main-body part 13 Large diameter part 14 Pile mounting part 15 Guide groove (guide part)
16 Guide groove 17 Clamp installation groove 18 Cylinder (locking mechanism)
19, 20 Clamp members 19a, 20a Support shafts 19b, 20b Clamping surface 21 Coil spring 30 Weedproof sheet 31 Convex part 32 Concave part A Concentric axis B Concentric axis C Rotating axis G Ground L1 Outer diameter L2 Length θ Twist angle

Claims (6)

A pile body portion in which a wire is spirally wound with a twist angle of 45 degrees or more;
A winding seat portion formed at the winding end portion of the wire rod at the base end portion of the pile body portion;
The tip of the pile main body has a shape obtained by cutting the wire with a single plane,
The winding seat includes an arc portion in which the wire is wound in an arc shape with a central angle of 270 degrees or more centered on the central axis of the pile main body portion, and a radial center side of the arc portion from one end of the arc portion A helical pile comprising a linear portion obtained by linearly extending the wire bent to a position exceeding the central axis. In claim 1,
The cut surface of the wire formed at the tip of the pile main body is a surface inclined toward the central axis of the pile main body with respect to the axial direction of the wire at the tip. Spiral pile. In claim 1 or 2,
The cross-sectional shape of the wire is a circular cross section having a diameter of 6 mm or more,
The outer diameter of the pile main body and the winding seat is 42 mm,
The spiral pile according to claim 1, wherein a length of the pile body portion in the central axis direction is 200 mm or more. A method for placing a helical pile according to any one of claims 1 to 3,
At the tip of the rechargeable electric impact driver, a chuck for detachably mounting the winding seat part is provided,
The chuck can be mounted with the spiral pile so that the rotation axis of the electric impact driver and the center axis of the pile main body portion are in agreement.
A helical pile placing method, wherein the helical pile is placed by transmitting the output rotation of the electric impact driver to the helical pile via the chuck. In claim 4,
The chuck is
A clamp member for sandwiching the straight portion;
A locking mechanism for locking the clamp member in a state of sandwiching the linear portion;
A guide portion for guiding the arc portion in a state where the linear portion is sandwiched between the clamp members,
The helical pile is driven by the electric impact driver in a state where the lock mechanism prevents the winding seat portion from being detached from the chuck and the guide portion restricts the inclination of the pile main body portion with respect to the rotation axis. A method for placing a helical pile characterized by Laying an embossed weedproof sheet with a predetermined uneven pattern on the ground,
The helical pile according to any one of claims 1 to 3 is driven on the ground at a predetermined interval from above the weed prevention sheet by the helical pile driving method according to claim 4 or 5. By fixing the grass for grass prevention to the ground,
Each spiral pile penetrates the grass for preventing grass and is placed so that each wire forming the arc portion and the straight portion is fitted in a gap between the convex portions in the concavo-convex pattern. The construction method of the sheet | seat for grass protection characterized by being performed.

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