JP2009057784A - Boring apparatus and method of boring hole in cast-in-place pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boring apparatus which eliminates disposal of surplus soil to curtails costs, and ensures concrete adhesion to a bored wall, and to provide a method of boring a hole in a cast-in-place pile. <P>SOLUTION: The boring apparatus A has: a driving shaft 1 having a front end 1a and a rear end 1b located on the same axis 1c, and having a first decentered portion 1d and a second decentered portion 1e arranged at intermediate locations; a rotor head 2 unrotatably supported by the front end 1a; a plurality of cone rotors 3 rotatably supported by the rotor head 2; a first rotor 4 rotatably arranged on the first decentered portion 1d; and a second decentered rotor 5 rotatably arranged on the second decentered portion 1e. The first decentered portion 1d and the second decentered portion 1e have the same dimension e, but they are decentered in mutually different locations. The cone rotors 3 are arranged such that the axes 3d thereof cross each other at a location O on an extension of the axis 1c, and that distances from the core 1c become larger at locations more separate from the crossing location O and closer to the rotor head 2. Further the first rotor 4 and the second rotor 5 each have screw grooves 7 formed in a peripheral surface thereof. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a drilling device for compacting earth and sand to form a hole, and a hole in a cast-in-place pile using this drilling device, in particular, a screw hole having a screw groove on a hole wall. And a forming method.

  The cast-in-place pile method has low vibration and low noise, and is used in a wide range from large buildings to small buildings such as houses. In this cast-in-place pile method, a cylindrical pipe is driven into the site, and a concrete pile is drawn out by placing the concrete pipe in it. Drilling is performed using an excavator such as an earth drill or reverse circulation drill. However, there is a construction method such as a construction method in which concrete is placed in this hole to make a concrete pile.

  As described above, the cast-in-place pile method generally excavates the ground with an earth auger, a rotating bit, or a rotating bucket. And after excavating the ground, the earth and sand are removed, and after the excavation depth reaches the required dimension, concrete is inserted by inserting a reinforcing bar, and concrete curing is performed to make a concrete pile.

  In each of the above cast-in-place pile methods, it is essential to discharge the excavated soil. For example, even when a single house is constructed, the number of piles is several to several tens. For this reason, there is a problem that a large amount of residual soil processing is required and costs are increased.

  In addition, the surface of the hole wall drilled by the earth auger, rotating bit, or rotating bucket is not controlled, and whether or not the placed concrete adheres securely to the hole wall and is integrated. There is a problem that it is not obvious.

  An object of the present invention is to provide a drilling device capable of reducing the cost by eliminating the need for residual soil processing in the cast-in-place pile construction method, It is to provide a hole forming method.

  In order to solve the above-described problem, a perforating apparatus according to the present invention includes a drive shaft in which a front end portion and a rear end portion are on the same axis and a first eccentric portion and a second eccentric portion are provided in the middle, and a front end of the drive shaft. A rotor head that is non-rotatably supported by the portion, a plurality of cone rotors that are formed in a substantially conical shape and are rotatably supported by the rotor head, and a first rotor that is rotatably disposed at the first eccentric portion A second eccentric rotor rotatably disposed on the second eccentric portion, and the first eccentric portion and the second eccentric portion of the drive shaft are configured to be eccentric in different directions with the same dimensions. The plurality of cone rotors intersect with each other at substantially the same position on the extension line of the shaft center of the tip end portion of the drive shaft, and the distance from the shaft center of the drive shaft toward the rotor head side from the intersecting position. Inclined so that it becomes larger and the top There are disposed close to each other at an intersection side of the axis, an outer peripheral surface of the first rotor and the second rotor are those thread groove is formed.

  Further, the cast-in-place pile forming method according to the present invention is a cast-in-place pile forming method for forming a hole using the drilling apparatus according to claim 1 when constructing the cast-in-place pile, The cone rotor is suspended so that the top of the cone rotor faces downward, and a driving means for rotating the driving shaft is connected to the driving shaft and a thrust applying means for applying a thrust to the driving shaft is connected. By rotating the rotor head and propelling the cone rotor into the ground, the earth and sand are consolidated to form a hole, and by further propelling while rotating the rotor head, the hole wall is formed by the first rotor and the second rotor. After forming a hole with a predetermined depth, a hole with a screw groove formed in the hole wall is formed by pulling up the drilling device while rotating the drive shaft in the reverse direction. It is intended to.

  In the drilling device of the present invention, a plurality of cone rotors are rotatably arranged on the rotor head supported non-rotatably at the tip of the drive shaft so that the tops intersect at the same position on the extension line of the axis of the drive shaft. Therefore, the rotor head can be rotated by rotationally driving the drive shaft. The cone rotors arranged on the rotor head are configured so that they can freely rotate. When the rotor head is lowered from above the ground and the cone rotor enters the ground, each cone rotor comes into contact with the ground. Rotate due to friction. For this reason, with the rotation of the rotor head, the rotation of the cone rotor, and the propulsion of the rotor head, the earth and sand are consolidated, and a circular hole can be formed in the ground.

  In addition, the first eccentric portion and the second eccentric portion of the drive shaft are eccentric in the same dimension and in different directions, and the first rotor, the first eccentric portion, and the first rotor having screw grooves formed on the outer peripheral surface thereof, Since the two rotors are rotatably supported, the first rotor and the second rotor can press the thread groove against the hole wall compacted by the cone rotor to form the thread groove with respect to the hole wall. At this time, since the first rotor and the second rotor are eccentric in the same eccentric dimension and in different directions, it is possible to balance the reaction force generated when pressed against the hole wall, which is impossible for the drive shaft. No bending force is applied.

  In addition, since the first rotor and the second rotor are pressed against the hole wall to form a screw groove, the screw groove formed in the hole wall can support the reaction force in the propulsion direction, and the drilling device can be smoothly Promotion and withdrawal can be realized.

  Also, in the cast-in-place pile forming method according to the present invention, the earth and sand are consolidated with the rotation of the cone rotor and the propulsion of the rotor head, so that a hole is formed, so that the hole is formed by excavating the ground. , No earth and sand to be eliminated. Therefore, it is possible to reduce the cost required for the remaining soil processing by realizing the soil-free construction method.

  A screw groove can be formed by further pressing the first rotor and the second rotor against the hole wall formed by pressing the earth and sand with a cone rotor. The screw groove formed on the hole wall is engaged with the screw groove formed on the outer peripheral surface of the first rotor and the second rotor, and the screw groove formed on the hole wall is a compacted soil and sand. Therefore, it has sufficiently high strength as compared with the hole wall of the hole formed by excavation. For this reason, it becomes possible to support the reaction force with respect to the thrust which the thread groove of a hole wall acts on a perforation apparatus, and can implement | achieve smooth propulsion.

  Then, after forming a hole with a preset depth, when the drive shaft is reversely rotated and a pulling force is applied, the drilling device rises and escapes according to the thread groove lead formed in the hole wall. A hole having a thread groove on the hole wall is formed.

  Therefore, a cast-in-place pile can be constructed by inserting a reinforcing bar into the hole and placing concrete. In particular, since the screw groove is formed in the hole wall, the ground concrete and the concrete can be surely integrated by allowing the placed concrete to enter the screw groove and solidify.

  In addition, when a vertical force acts on the cast-in-place pile, the pile is integrated with the ground via a screw groove, so the force acts as a shearing force on the thread groove portion, which is high. Support force can be realized.

  Hereinafter, the most preferable embodiment of the perforation apparatus according to the present invention will be described. The drilling device of the present invention is preferably used when forming a hole in a cast-in-place pile with no soil with respect to the ground, and in particular, the rotor head placed at the tip is rotated to be placed on the rotor head. Holes were formed by compacting earth and sand with a plurality of cone rotors, and the outer peripheral surfaces of the first and second rotors arranged following the rotor head were pressed against the hole walls to form the outer peripheral surfaces of these rotors. A thread groove corresponding to the thread groove can be formed in the hole wall.

  First, the configuration of the punching device will be described with reference to the drawings. FIG. 1 is a diagram for explaining the overall configuration of the perforation apparatus, and also shows a part of a hole in which a thread groove is formed in a hole wall. FIG. 2 is a front view of FIG. 1 viewed from the top side of the cone rotor. 3 is a cross-sectional view taken along the line AA in FIG. FIG. 4 is a diagram illustrating an example of thread grooves formed on the outer peripheral surfaces of the first rotor and the second rotor.

  The drilling device A shown in the figure is a device for realizing the cast-in-place pile method, and in particular, for forming a hole B having a screw groove C in the ground by compacting earth and sand. For this reason, the drilling device A includes a drive shaft 1 having a front end portion 1a and a rear end portion 1b on the same axis 1c and having a first eccentric portion 1d and a second eccentric portion 1e in the center, and a front end portion 1a of the drive shaft 1. The rotor head 2 that is rotatably supported by the rotor head, the plurality of cone rotors 3 that are rotatably supported by the rotor head 2, the first rotor 4 that is rotatably supported by the first eccentric portion 1d, and the second eccentricity. A second rotor 5 rotatably supported by the portion 1e.

  The drive shaft 1 is connected to a drive device such as a ground drill drive device or a rotary bit or a rotary bucket drive device (for example, a rotary drive device shown in FIG. 5 described later) used in a cast-in-place pile method (not shown). A rotational force and a thrust are applied by the driving device to rotate the cone rotor 3 and to propel the cone rotor 3 and the rotors 4 and 5.

  The drive shaft 1 includes a front end portion 1a, a first eccentric portion 1d continuous with the front end portion 1a, a second eccentric portion 1e continuous with the first eccentric portion 1d, and a rear end portion continuous with the second eccentric portion 1e. 1b. The front end portion 1a and the rear end portion 1b are disposed on the same shaft center 1c, and the first eccentric portion 1d and the second eccentric portion 1e are offset from the shaft center 1c by the same dimension e and in directions opposite to each other. I have a heart. Therefore, the distance between the axis of the first eccentric part 1c and the axis of the second eccentric part 1e is 2e.

  The value of the amount of eccentricity e is not particularly limited, but is preferably at least as large as the depth of a thread groove to be described later.

  A rotor head 2 is attached to the tip 1a of the drive shaft 1 via a key 10, and the rotor head 2 is supported so as not to rotate with respect to the drive shaft 1 by this configuration. The rotor head 2 is formed in a substantially disc shape, and has a dimension that is approximately equal to or slightly smaller than the diameter of the pilot hole (diameter D of the hole wall F) of the screw groove C whose outer diameter is set in advance. ing.

  A plurality of cone rotors 3 and 3 are rotatably supported on the rotor head 2. The number of cone rotors 3 disposed on the rotor head 2 is not particularly limited as long as it is two or more. In this embodiment, three cone rotors 3 are rotatably supported by the rotor head 2.

  The cone rotor 3 is formed in a conical shape having a top portion 3a and a base portion 3b, and a bearing chamber 3c is formed inside the base portion 3b. The cone angle of the cone rotor 3 and the diameter of the base portion 3b are not uniquely set. Conditions such as the diameter of the cast-in-place pile to be constructed and the properties of the ground, and the drive shaft 1 on the outer peripheral surface of the cone rotor 3 Is set in correspondence with the inclination angle of the axis 1c. However, the diameter of the base portion 3b is smaller than ½ of the diameter of the rotor head 2.

  In addition, the cone rotor 3 does not need to be a cone shape in an accurate sense, and the outer peripheral surface from the top part 3a to the base part 3b may be a gentle curve.

  The respective cone rotors 3 arranged in the rotor head 2 are arranged at equiangular intervals (in this embodiment, at intervals of 120 degrees) on the circumference centered on the axis 1c of the drive shaft 1. In particular, the shaft center 3d of each cone rotor 3 intersects at substantially the same position O on the extension line of the shaft center 1c of the drive shaft 1, and the shaft center of the drive shaft 1 from the intersecting position O toward the rotor head 2 side. It is arranged so as to be inclined so that the distance from 1c increases.

  For this reason, a mounting seat 2a having a surface orthogonal to the axis 3d of the inclined cone rotor 3 is provided at the position of the cone rotor 3 on the front surface of the rotor head 2.

  Note that the angle formed between the axis 3c of the cone rotor 3 and the axis 1c of the drive shaft 1 is not particularly limited, and the axis of the drive shaft 1 on the outer peripheral surface of the three cone rotors 3 disposed in the rotor head 2 is not limited. It is set corresponding to the inclination angle (set in advance corresponding to the conditions such as the diameter of the cast-in-place pile to be constructed, the property of the ground) and the like configured with respect to the core 1c.

  The top portions 3a of the cone rotors 3 are arranged close to each other on the side of the intersection O between the shaft center 1c and the shaft center 3d of the drive shaft 1. That is, the cone rotors 3 have postures in which the tops 3 a are close to each other on the extension line of the axis 1 c of the drive shaft 1. Each cone rotor 3 is rotatably supported by the rotor head 2 via a support shaft 11.

  The bearing chamber 3 c formed inside the cone rotor 3 is formed with a fitting tolerance so that the two bearings 12 a and 12 b attached to the support portion 11 a of the support shaft 11 can be fitted. The bearings 12 a and 12 b attached to the support portion 11 a of the support shaft 11 are fixed to a predetermined position by a nut 13 fastened to the tip of the support shaft 11.

  Further, a seal portion 11 b is formed continuously from the support portion 11 a of the support shaft 11, and the portion up to the seal portion 11 b is configured to be fitted into the bearing chamber 3 c of the cone rotor 3. In particular, on the base 3b side of the bearing chamber 3c formed in the cone rotor 3, a closing member 14 fitted with a sealing material 14a is attached to the inner peripheral surface, and the sealing member 11b of the support shaft 11 is sealed by the closing member 14. By doing so, earth and sand and groundwater can be prevented from entering the bearing chamber 3c.

  An attachment portion 11c is formed on the support shaft 11 continuously to the seal portion 11b. The mounting portion 11c is fixed to the rotor head 2 by being attached to a mounting hole 2b formed in a mounting seat 2a provided in the rotor head 2 through a key (not shown) or fitted in a tapered shape. Yes.

  Accordingly, the cone rotor 3 is supported by the support shaft 11 by fitting the support portion 11a of the support shaft 11 into the bearing chamber 3c of the cone rotor 3 via the bearings 12a and 12b in advance and mounting the closing member 14 on the seal portion 11b. Can be freely rotated. Then, the cone rotor 3 is attached to the front surface of the rotor head 2 so as to be freely rotatable by fitting and fixing the attachment portion 11c of the support shaft 11 into the attachment hole 2b formed in the attachment seat 2a of the rotor head 2. Is possible.

  Two bearings 21 are attached to the first eccentric portion 1 d of the drive shaft 1, and the first rotor 4 is supported via the bearings 21 so as to be freely rotatable. That is, the first rotor 4 is not rotated by being driven by the drive shaft 1, and is rotated by friction when the outer peripheral surface comes into contact with the hole wall F of the hole B. For this reason, the rotation direction of the first rotor 4 is opposite to the rotation direction of the drive shaft 1. For example, when the drive shaft 1 rotates clockwise as shown in FIG. 3 with contact friction acting on the outer peripheral surface of the first rotor 4, the first rotor 4 rotates counterclockwise.

  A thread groove 7 is formed on the outer peripheral surface of the first rotor 4, and is pressed against a hole wall F that is subsequent to the rotor head 2 and is consolidated by a plurality of cone rotors 3 disposed on the rotor head 2. The screw groove C can be formed in the hole wall F while rotating eccentrically by the friction at this time.

  Accordingly, the diameter D1 of the thread groove C formed in the hole wall F is larger than the outer diameter d1 of the thread groove 7 formed on the outer peripheral surface of the first rotor 4.

  When the first rotor 4 is brought into pressure contact with the hole wall F, the hole wall F has a substantially flat surface consolidated by the cone rotor 3, and the reaction force from the hole wall F increases. For this reason, the 1st rotor 4 is comprised so that a contact surface pressure can be lowered | hung by having sufficient length. That is, the length L1 of the first rotor 4 is set in advance according to conditions such as the diameter of the cast-in-place pile to be constructed, the depth of the thread groove, and the properties of the ground.

  Further, the top portion 7a of the screw groove 7 formed on the outer peripheral surface of the first rotor 4 surely bites into the hole wall on the projecting side from the shaft center 1c of the drive shaft 1, and separates from the hole wall on the fitting side. It is configured as follows. Therefore, for example, when the eccentric dimension e and the height of the screw groove 7 (difference between the top portion 7a and the valley portion 7b) are equal, the outer diameter of the first rotor 4 (the diameter of the top portion 7a of the screw groove 7) is a plurality of It is substantially equal to the diameter of the circle connecting the base 3b of the cone rotor 3 (diameter D of the hole wall F).

  The thread groove 7 may be formed in a spiral shape having a sufficient depth, and the shape is not limited. For example, the trapezoidal screw shown in FIG. 4A, the triangular screw shown in FIG. 4B, or the round screw shown in FIG. And it is preferable to selectively employ each of the above-mentioned screws or screws of other shapes in correspondence with the ground formation for constructing the cast-in-place pile. For example, when a cast-in-place pile is constructed in a gravel layer, the thread groove 7 is preferably a triangular screw. In any case, when the screw groove C is formed by compacting the earth and sand to the hole wall, the shape is preferably such that the earth and sand can be detached without adhering to the screw groove C.

  Further, the pitch P and the number of strips of the thread groove 7 are not limited, and are preferably set in advance according to conditions such as the diameter of the cast-in-place pile to be constructed and the properties of the ground. For example, in the ground where the propulsion depth per rotation of the rotor head 2 can be increased, it is preferable to secure the number of threads without increasing the pitch by setting the thread groove 7 as a multi-thread screw (2 to 3). .

For example, the diameter of the screw groove C formed in the hole wall F is D (D1), the diameter of the screw groove 7 formed on the outer peripheral surface of the first rotor 4 is d (d1), and the top portion 7a of the screw groove 7 is set. Where P is the pitch, the number of threads 7 is n, the rotational speed of the drive shaft 1 is N, and the propulsion speed of the drilling device A is V.
V = D / d-1 * P * n * N
Is established. This formula is applied to the design calculation of the rotational speed and torque of the drive shaft 1 according to the diameter of the cast-in-place pile and the properties of the ground.

  Two bearings 22 are attached to the second eccentric portion 1 e of the drive shaft 1, and the second rotor 5 is supported via the bearings 22 so as to be freely rotatable. Therefore, like the first rotor 4, the second rotor 5 is not driven and rotated by the drive shaft 1, and the friction when the outer peripheral surface comes into contact with the screw groove C already formed by the first rotor 4. By this, it rotates in the direction opposite to the rotation direction of the drive shaft 1.

  On the outer peripheral surface of the second rotor 5, screw grooves 7 having the same pitch P and the same number of threads as the screw grooves 7 formed on the outer peripheral surface of the first rotor 4 are formed. However, the outer diameter d2 of the second rotor 5 does not have to be equal to the outer diameter d1 of the first rotor 4, and d2 may be slightly larger than d1.

  The second rotor 5 is configured to follow the first rotor 4 and be further press-contacted with the thread groove C formed in the hole wall F by the first rotor 4. Therefore, when the outer diameter d2 of the second rotor 5 and the outer diameter d1 of the first rotor 4 are equal, the screw groove 7 formed in the second rotor 5 is the screw already formed by the screw groove 7 of the first rotor 4. The contact is made so as to correct the groove C. Further, when the outer diameter d2 of the second rotor 5 is larger than the outer diameter d1 of the first rotor 4, the screw groove C already formed by the screw groove 7 of the first rotor 4 is further consolidated to make the screw groove C stronger. Can be formed.

  Whether the outer diameter d2 of the second rotor 5 is equal to or larger than the outer diameter d1 of the first rotor 4 is appropriately determined according to conditions such as the properties of the ground for constructing the cast-in-place pile. It is preferable to set.

  The second eccentric portion 1e of the drive shaft 1 is eccentric to the opposite side of the first eccentric portion 1d with the shaft center 1c as the center. For this reason, the reaction force acting on the drive shaft 1 when the screw groove 7 of the first rotor 4 is pressed against the hole wall F and compacted, and the screw groove C in which the screw groove 7 of the second rotor 5 is already formed. It is possible to cancel out the reaction force acting on the drive shaft 1 when being pressed against and compacted.

  When the second rotor 5 is in pressure contact with the thread groove C already formed by the first rotor 4, the thread groove C is sufficiently consolidated and thus has a high supporting force. For this reason, even if the length L2 of the second rotor 5 is made smaller than the length L1 of the first rotor 4, the reaction force acting on the drive shaft 1 via the first rotor 4 and the second rotor 5 are driven. It is possible to balance the reaction force acting on the shaft 1.

  A bearing chamber 4a into which the bearing 21 is fitted is formed at the center of the first rotor 4, and mechanical seals 23a and 23b are attached to both ends of the bearing chamber 4a in the length direction. The mechanical seal 23a is in contact with the sliding member 24a fixed to the rotor head 2, and the mechanical seal 23b is in contact with the sliding member 24b provided in the second rotor 5 to prevent infiltration of groundwater and earth and sand into the bearing chamber 4a. It is out.

  A bearing chamber 5a that fits the bearing 22 is also formed at the center of the second rotor 5, and a sliding member 24b is fixed to the first rotor 4 side. Further, a cap-shaped closing member 26 having a sealing material 25 fitted to the inner peripheral surface is fixed to the rear end 1b side of the drive shaft 1, and ground water and earth and sand enter the bearing chamber 5a by the sealing material 25. Is preventing.

  The rear end portion 1b of the drive shaft 1 is connected to a drive device such as a ground drill drive device or a rotary bit drive device or a rotary bucket drive device used in the cast-in-place pile method described above. For this reason, the rear end 1b has a shape corresponding to the configuration of the output shaft of the drive device to be connected. In this embodiment, a drive device having a stem rod 31 is provided, and the stem rod 31 can be connected to the stem rod 31 via a pin 32.

  The shape of the rear end portion 1b of the drive shaft 1 is not limited to this embodiment, and is configured to correspond to the shape of the output portion of the drive device to be connected.

  Next, a method for forming the hole B of the cast-in-place pile using the drilling apparatus A configured as described above will be described, and a procedure for constructing the cast-in-place pile using the hole B will be described. FIG. 5 is a diagram illustrating a state in which the hole B is formed by connecting the punching device A to a crawler excavator equipped with a driving device. FIG. 6 is a diagram illustrating a procedure for constructing a cast-in-place pile using the hole B.

  As shown in FIG. 5, the drilling device A is suspended by connecting the rear end portion 1 b of the drive shaft 1 to the stem rod 31 of the drive device 30 that generates rotational force and propulsive force provided on the crawler excavator. The drilling device A is lowered while rotating the drive shaft 1 (clockwise or counterclockwise), and the top 3 a of the cone rotor 3 provided on the rotor head 2 is grounded.

  As shown in FIG. 2, as the rotor head 2 rotates, a plurality of cone rotors 3 rotate as a whole around the axis 1c, and at the same time, each cone rotor 3 rotates by the contact friction with the ground. The soil is consolidated while rotating in the opposite direction. Due to the thrust applied through the drive shaft 1, the drilling device A advances perpendicularly to the ground, and with this progress, a hole is formed in the ground without any soil.

  When the drilling device A is fitted with the rotor head 2 in the ground, a hole wall F having a diameter D substantially equal to the diameter of a circle connecting the base portions 3b of the cone rotors 3 is formed on the ground. The hole wall F becomes a pilot hole of the screw groove C formed by the screw groove 7 formed on the outer peripheral surface of the subsequent first rotor 4.

  The first rotor 4 following the rotor head 2 arrives at the hole wall F by the subsequent propulsion of the drilling device A. As shown in FIGS. 1 and 3, as the drive shaft 1 rotates, the first rotor 4 rotates eccentrically with the dimension e about the shaft center 1c. With this eccentric rotation, first, the top 7a of the thread groove 7 contacts the hole wall F at the point H, and the first rotor 4 rotates in a direction opposite to the rotation direction of the drive shaft 1 by friction.

  Therefore, when the thread groove 7 formed in the first rotor 4 is a right-hand thread and the drive shaft 1 rotates to the right, the thread groove C formed in the hole wall F is a left-hand thread. However, it does not matter whether the screw groove C is a right-hand screw or a left-hand screw. If the screw groove C having a sufficient depth is formed in the hole wall F, the concrete is passed through the screw groove C. Can be integrated.

  With the subsequent rotation of the drive shaft 1, the hole wall F is consolidated by the eccentric dimension e while the first rotor 4 rotates, and the top 7 a of the screw groove 7 is fitted into the hole wall F, and the point G (the eccentric direction) A thread groove C is formed on the extension line or on the downstream side in the rotation direction of the first rotor 4 with respect to the extension line. With further rotation and propulsion of the drive shaft 1, a continuous thread groove C is formed in the hole wall F by the thread groove 7 formed on the outer peripheral surface of the first rotor 4.

  When the first rotor 4 is fitted into the hole wall F over the entire length as the drilling device A is propelled, the second rotor 5 reaches the hole wall F. When the screw groove 7 formed on the outer peripheral surface coincides with the screw groove C already formed in the hole wall F, the second rotor 5 is fitted to the screw groove C and includes the top portion 7a or the other side surface. The surfaces come into contact and rotate due to friction. The part where the first rotor 5 is in contact with the hole wall F is in a symmetrical position with the part where the first rotor 4 is in contact with the hole wall F, and the reaction force of the hole wall F can be offset.

  As described above, along with the propulsion of the drilling device A, a compacted hole wall F is formed in the ground, and subsequently a hole B in which a thread groove C is formed in the hole wall F is formed. When the depth of the hole B reaches a preset dimension, the punching device A is pulled back from the hole B.

  That is, the drive device 30 provided on the crawler excavator rotates the drive shaft 1 in the direction opposite to the rotation direction when the hole B is formed and applies a force in the pull-back direction, whereby the first rotor 4, The screw groove 7 of the rotor 5 can be rotated along the screw groove C formed in the hole wall F and pulled back to the ground. When the drilling device A is pulled back to the ground, the ground is formed with a hole B in which a thread groove C is formed in the hole wall F.

  Next, a procedure for constructing a cast-in-place pile using the holes B configured as described above will be described with reference to FIG.

  First, as shown in FIG. 2A, the casing 41 is installed on the ground portion of the hole B, and then the reinforcing bar 42 is inserted into the hole B. Next, as shown in FIG. 2B, the tremy tube 43 is installed so that the tip portion approaches the bottom of the hole B. Thereafter, as shown in FIG. 4C, concrete 44 is placed through the treme tube 43, and the treme tube 43 is sequentially pulled back as the amount of placement increases. Further, as shown in FIG. 4D, the casing 41 is pulled out, and a required amount of concrete 44 is placed. Then, as shown in FIG. 5E, when a required amount of concrete 44 is placed in the hole B, a cast-in-place pile is constructed by the concrete 44 that has been placed and hardened.

  In the cast-in-place pile constructed as described above, the concrete 44 placed in the hole B enters the screw groove C formed in the hole wall F and solidifies, and can be reliably integrated. Become. Further, since the thread groove C has a lead angle corresponding to the pitch P and the number of strips, the air entrained when the concrete 44 is placed can rise along the thread groove C without staying in part. It is possible to build a strong pile with few bubbles.

  In this embodiment, the driving shaft 1 of the drilling device A is configured to be driven by the driving device 30 provided on the crawler excavator. However, the present invention is not limited to this configuration, and as described above, the driving of the ground drill is performed. It is also possible to use a device, a rotary drill or a rotary bit drive.

  The perforating apparatus according to the present invention can be used when a relatively small building such as a house or a cast-in-place pile of a large building is constructed. In particular, the cast-in-place pile forming method using the drilling apparatus according to the present invention is useful as an earth screw method for forming the hole B in which the screw groove C is formed in the ground regardless of the diameter of the pile. It is.

It is a figure explaining the whole structure of a piercing | piercing apparatus, and also describes a part of hole which formed the screw groove in the hole wall. It is the front view of FIG. 1 seen from the top part side of the cone rotor. It is AC sectional drawing of FIG. It is a figure explaining the example of the thread groove formed in the outer peripheral surface of a 1st rotor and a 2nd rotor. It is a figure explaining the state which connects the drilling apparatus A to the crawler excavator carrying a drive device, and forms the hole B. FIG. It is a figure explaining the procedure which constructs a cast-in-place pile using the hole B. FIG.

Explanation of symbols

A Drilling device B Hole C Thread groove D Diameter of hole wall consolidated by cone rotor D1 Diameter of screw groove C d1 Diameter of first rotor d2 Diameter of second rotor e Eccentric dimension F Hole walls G, H of first rotor Contact point between the top of the thread groove and the hole wall L1 Length of the first rotor L2 Length of the second rotor P Pitch of the thread groove O Intersection of the top of the plurality of cone rotors and the shaft center 1 Drive shaft 1a Tip 1b Rear end 1c shaft center 1d first eccentric portion 1e second eccentric portion 2 rotor head 2a mounting seat 2b mounting hole 3 cone rotor 3a top 3b base 3c bearing chamber 3d shaft 4 first rotor 4a bearing chamber 5 second rotor 5a Bearing chamber 7 Thread groove 7a Top portion 7b Valley portion 10 Key 11 Support shaft 11a Support portion 11b Seal portion 11c Mounting portion 12a, 12b Bearing 13 Nut 14 Closure member 14 Sealing members 21 and 22 bearing 23a, 23b mechanical seal 24a, 24b sliding member 25 sealing member 26 closing member 30 driving unit 31 stem rod 32-pin 41 casing 42 reinforcing bar cage 43 tremie pipe 44 Concrete

Claims (2)

A drive shaft having a front end portion and a rear end portion on the same axis, and a first eccentric portion and a second eccentric portion provided in the middle; a rotor head supported non-rotatably on the front end portion of the drive shaft; and a substantially conical shape A plurality of cone rotors that are rotatably supported by the rotor head, a first rotor that is rotatably disposed on the first eccentric portion, and a second that is rotatably disposed on the second eccentric portion. An eccentric rotor, wherein the first eccentric portion and the second eccentric portion of the drive shaft are configured to be eccentric in different directions with the same dimensions, and each of the plurality of cone rotors has an axis of the drive shaft. It intersects at substantially the same position on the extension line of the axis of the tip and is inclined so that the distance from the axis of the drive shaft increases from the intersecting position toward the rotor head, and the top is the axis. Placed close to each other on the crossing side of the heart Cage, punching device, wherein a screw groove is formed on the outer circumferential surface of the first rotor and the second rotor. A method of forming a hole in a cast-in-place pile, wherein a hole is formed using the drilling device according to claim 1 when constructing the cast-in-place pile, and the suspension is suspended so that the top of the cone rotor of the drilling device is down, The drive means for rotating the drive shaft is connected to the drive shaft and the thrust applying means for applying thrust to the drive shaft is connected, and then the cone rotor is grounded while rotating the drive shaft and rotating the rotor head. The hole is formed by compacting the earth and sand by propelling to the next, and further, the screw groove is formed in the hole wall by the first rotor and the second rotor by propelling while rotating the rotor head. After forming a hole, the hole formation method of the cast-in-place pile characterized by forming the hole by which the screw groove was formed in the hole wall by pulling up the drilling device, reversely rotating a drive shaft.