JP2013091902A - Construction device and method for on-site constructed pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a construction device for an on-site constructed pile which enables repeated use of an excavation head to reduce cost for construction work of the on-site constructed pile, and a construction method for the on-site constructed pile using the construction device.SOLUTION: An excavation head 7 formed by integrating a plurality of divisible parts is fitted to the lower end of a hollow excavation rod 6, and a pile hole is excavated in the ground by the excavation head 7. When the excavation rod 6 reaches a predetermined depth in the ground, the inside of the excavation rod 6 is filled with a pile material C. Subsequently, when the excavation rod 6 is raised, the excavation head 7 falls off from the lower end of the excavation rod 6 to discharge the pile material C into the pile hole. At this time, the excavation head 7 is separated into a plurality of parts, which are lifted in the pile material C filled into the pile hole by wires according to rising of the excavation rod 6, and recovered on the ground.

Description

  TECHNICAL FIELD The present invention relates to a construction device for a field-built pile that is built in the ground and supports a building, and a method for constructing a field-built pile using the device.

  Conventionally, when placing a small-diameter field-built pile as a foundation pile for a small-scale house or the like, for example, as described in Patent Document 1, a hollow with a drilling head (bottom plate) having a drilling blade is attached. The excavation rod (steel pipe) is excavated to the desired depth in the ground, and pile material such as ready-mixed concrete and mortar is poured into the excavation rod and filled, and then the excavation head is left in the ground and the excavation rod is left. The pile material is poured into the hole of the pile and solidified by pulling up.

JP 2005-133289 A

  In the conventional method for constructing an on-site pile as described above, it is common to attach a large-diameter spiral bottom plate to the tip of the steel pipe pile for the purpose of increasing the bearing capacity of the pile. In the design of such piles, the bottom plate disturbs the ground around the pile when it is press-fitted into the ground, so when calculating the force that the ground supports the pile against the load acting on the pile, The surface friction is not approved by the government, and it is common to design with only the tip support force.

  On the other hand, site-built piles intended for use in foundations for small-scale houses, etc. have a small bearing load, so the pile diameter is small, and cheap raw concrete is used instead of steel pipe, and the area of the lower end is the peripheral surface. Therefore, if you excavate so as not to disturb the ground around the pile using a small-diameter excavation head that is almost the same as the pile diameter, the bearing capacity of the pile is calculated only from the peripheral surface friction of the pile. It is possible to design piles.

  However, since the excavation head with the same diameter as the pile diameter has a small pressure-receiving area, leaving it in the ground hardly contributes to the support capacity of the pile, but the excavation head is used as a consumable part by the number of piles to be created. There was a problem that it was necessary to prepare, and the construction cost was high.

  Therefore, the present invention eliminates the problems in the conventional technology as described above, the excavation head can be used repeatedly, and the construction device of the on-site construction pile that can reduce the cost of construction work of the on-site construction pile and the construction It aims at providing the construction method of the field construction pile using a device.

  An on-site construction pile construction apparatus of the present invention provided for the above purpose includes a drive head that is supported by a guide column of a work vehicle so as to be movable up and down, and a hollow that is rotationally driven with an upper end supported by the drive head. And a drilling head that is detachably attached to a lower end of the drilling rod, wherein the drilling head comprises a plurality of split bodies that can be combined and separated. A lid that is fitted in a state in which rotation is restricted to a lower end opening of the excavation rod in the combined state, and excavation that protrudes from a lower surface of at least one divided body that constitutes the lid Each of the divided bodies is connected to a connecting portion provided on the inner wall surface of the excavation rod or the drive head side by a flexible strip, and is joined to the lower end of the excavation rod. When fitted as a body The flexible strip is accommodated in the excavation rod, and the lid is separated from the lower end of the excavation rod by the operation of pulling up the excavation rod from the ground, so that the divided bodies are separated from each other. It is suspended in series and collected.

  In the on-site construction pile construction apparatus, when the excavation rod rotates in the forward direction with respect to the lid on the position near the outer periphery of the upper surface of the lid and the inner peripheral surface of the lower end opening of the excavation rod, they are engaged with each other. And a plurality of sets of engagement portions that are disengaged from each other when the excavation rod rotates in the opposite direction while maintaining the fitted state of the lower end of the excavation rod and the lid. desirable. It is also desirable that the flexible strip is connected to a connecting portion provided on the inner wall surface of the excavating rod via a rotatable joint.

In addition, the method of the field construction pile of the present invention provided for the above purpose is a method of constructing the field construction pile using the construction device for the field construction pile described above, in a state where the excavation rod is upright. A first step of combining the divided bodies constituting the lid body of the excavation head, housing the flexible strip in the excavation rod, and then attaching the lid body to the lower end opening of the excavation rod;
The second step of lowering the excavation rod while rotating forward in the excavation direction to excavate to a predetermined depth in the ground, and the third step of charging and filling the pile material into the excavation rod from its upper end side And a pile formed by excavating in the second step from the lower end of the opened excavation rod while lifting the excavation rod in reverse and separating the lid of the excavation head downward from the lower end of the excavation rod. The fourth step of discharging and filling the pile material into the hole, and after the fourth step, the lower end of the excavation rod is further raised and buried in the pile material filled in the pile hole A fifth step is included in which each of the divided bodies is pulled up to the ground and collected in a state of being suspended in series below the excavation rod.

  According to the construction device for an on-site construction pile according to the invention described in claim 1, after the construction of the on-site construction pile, the excavation head can be recovered and reused without leaving the ground. In addition, the cost of construction work for site construction piles can be greatly reduced.

  According to the construction device for a field-built pile according to the invention described in claim 2, the excavation head is engaged with the excavation rod at a position away from the ground, and the fitting state is maintained. Therefore, the excavation head can be easily attached to the excavation rod, and the excavation head can be reliably held on the excavation rod during excavation of the pile hole.

  According to the construction device for an on-site construction pile according to the invention described in claim 3, the flexible strip is connected to the connecting portion provided on the inner wall surface of the excavation rod via a rotatable joint. Therefore, when the excavation rod 6 is raised while rotating and the excavation head is collected on the ground, each division of the excavation head individually connected by a flexible strip rotates in the pile material. Therefore, twisting of the flexible strips can be prevented.

  According to the construction device of the field construction pile according to the invention described in claim 4, after the field construction pile is placed, the field construction pile is used for recovery and reuse without leaving the excavation head in the ground. It is not necessary to prepare a new excavation head every time for the construction work to be carried out, and in particular, when the number of on-site construction piles is large, the construction cost can be greatly reduced.

It is a side view of the work vehicle equipped with the construction device of the field construction pile in one embodiment of the present invention. It is a fragmentary sectional view which shows the internal structure of the excavation rod used for the construction apparatus shown in FIG. It is the perspective view which looked at the lower end part and excavation head of the excavation rod used for the construction | assembly apparatus shown in FIG. 1 from diagonally upward. It is the perspective view which looked at the lower end part and excavation head of the excavation rod used for the construction | assembly apparatus shown in FIG. 1 from diagonally downward. It is the top view which looked at the excavation head used for the construction apparatus shown in Drawing 1 from the top, and (a) shows the united state and (b) shows the divided state, respectively. It is the top view which looked at the excavation head used for the construction apparatus shown in Drawing 1 from the top, and (a) shows the united state and (b) shows the divided state, respectively. It is the figure explaining the construction method of the field construction pile using the construction device shown in Drawing 1 in order of a process.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side view of a work vehicle equipped with an on-site construction pile construction device according to an embodiment of the present invention. As shown in the figure, the construction device 1 of the present invention has an arm on a work vehicle 2. A driving head 5 supported so as to be movable up and down with respect to the guide pillar 4 supported via 3, a hollow cylindrical excavation rod 6 supported at the upper end by the driving head 5 and driven to rotate, and The excavation head 7 is mounted on the lower end opening of the excavation rod 6.

  The work vehicle 2 is a vehicle that can be moved and moved by the crawler 2A and can be used with various work devices such as an earth auger attached according to the work contents. The guide column 4 is provided with a pair of guide sheaves 8A and 8B at its upper and lower ends, and an elevating chain 9 is spanned between the guide sheaves 8A and 8B.

  A driving head 5 is connected to the elevating chain 9, and the driving head 5 is moved up and down along the guide column 4 by driving the elevating chain 9 by driving means (not shown).

  On the lower surface of the drive head 5, a drive shaft 5A that can rotate in both forward and reverse directions is provided so as to protrude downward. The drive shaft 5A is detachably connected to a driven shaft 6A provided at the upper end of the excavation rod 6. When the drive shaft 5A is driven, the driven shaft 6A and the excavation rod 6 are integrated. To be rotated.

  A conical hopper portion 10 for pouring concrete is formed in the vicinity of the upper end of the excavation rod 6 to which the driven shaft 6A is fixed. The upper end of the hopper 10 is provided with an opening that concentrically surrounds the driven shaft 6 </ b> A, and this opening communicates with the inside of the hollow excavation rod 6.

  As shown in FIG. 2, a bracket 11 as a connecting portion protrudes from the inner wall of the excavating rod 6, and one end 12 </ b> A of the rotary joint 12 is connected to the tip of the bracket 11. Yes.

  Further, the other end 12B of the rotary joint 12 is structured to be rotatable around the longitudinal axis of the rotary joint 12 with respect to the one end 12A. The upper ends of three wires 13A, 13B, and 13C as flexible strips having different lengths are connected together.

  The lower ends of these wires 13A, 13B, and 13C are connected to the excavation head 7, and the excavation rod 7 is attached to the lower end of the excavation rod 6 as shown in FIG. 6 is stored inside.

  Next, FIG. 3 is a perspective view of the lower end portion of the excavation rod 6 and the excavation head 7 as viewed obliquely from above, and FIG. 4 is a perspective view of these viewed from obliquely below, as shown in these drawings. Furthermore, the excavation head 7 has a lid 14 that closes the lower end of the excavation rod 6.

  The lid body 14 has a thick disk shape having a step in the diameter of the outer peripheral surface, and the upper part a has an outer diameter that matches the inner diameter of the excavation rod 6. On the other hand, the lower part b has an outer diameter slightly larger than the outer diameter of the excavation rod 6, and in a state where the excavation head 7 is attached to the lower end of the excavation rod 6 as shown in FIG. The upper surface of the lower part b is in contact with the lower end surface of the excavation rod 6 so that the lower end opening of the excavation rod 6 is sealed.

  The lid body 14 is composed of three divided bodies 14A, 14B, and 14C. As shown in FIG. 4, the lower surface of the central divided body 14A has an isosceles triangle with a tip sharpened in a mountain shape. A shaped excavating blade 15 </ b> A is projected. Further, block-shaped excavating blades 15B and 15C protrude from the outer peripheral portions of the lower surfaces of the two divided bodies 14B and 14C adjacent to both sides of the divided body 14A so as to partially protrude outward from the outer peripheral surface. It is installed.

  As shown in FIG. 3, a pair of engaging portions 16 </ b> A and 16 </ b> B are provided on the outer peripheral portions of the upper surfaces of the two divided bodies 14 </ b> B and 14 </ b> C constituting the lid body 14. These engaging portions 16 </ b> A and 16 </ b> B are arranged so as to be rotationally symmetric with respect to the central axis of the lid body 14.

  On the other hand, engagement portions 17A and 17B that engage with these engagement portions 16A and 16B are provided on the inner peripheral surface of the lower end opening of the excavation rod 6. Engaging recesses 16A and 16B on the lid 14 side are provided with engaging recesses X, respectively, and engaging portions 17A and 17B on the excavation rod 6 side are fitted into these engaging recesses X, respectively. An engaging convex portion Y is provided.

  The set of the engaging portions 16A and 17A and the set of the engaging portions 16B and 17B are respectively fitted in the forward direction (in this case, the upper side of the excavating rod 6 with respect to the lid 14 by fitting the lid 14 to the excavating rod 6). When they are rotated in the clockwise direction as viewed from the top, they are engaged with each other, and when they are rotated in the reverse direction (counterclockwise as viewed from above), the engagement can be released.

  Further, each of the divided bodies 14A, 14B, and 14C constituting the lid body 14 is formed with a wire terminal fixing hole 18A, 18B, and 18C penetratingly formed below the wires 13A, 13B, and 13C described above. The end portions are inserted into the wire terminal fixing holes 18A, 18B, 18C, respectively, and are fixed to these by casting lead or tin-based metal from the back side of each of the divided bodies 14A, 14B, 14C.

  Next, FIG. 5 is a plan view of the excavation head 7 as viewed from above, and FIG. 6 is a plan view of the excavation head 7 as viewed from below, in which (a) is a combined state, (b ) Shows the divided state, and the lid body 14 is configured to be separable into three divided bodies 14A, 14B, and 14C.

  As shown in FIG. 6B, in the divided body 14A constituting the central portion of the lid body 14, the side edges T1 on both sides of the upper stage portion a parallel to the diametrical direction are more than the side edges T2 of the lower stage portion b. Also, each has a dimension S projecting on both sides.

  On the other hand, as shown in FIG. 5B, the side edge t1 of each upper stage portion a adjacent to the divided body 14A of the two divided bodies 14B and 14C arranged on both sides of the divided body 14A is Each side is retracted by a dimension S from the side edge t2.

  Therefore, when combined as one lid 14, the split surface of the upper part a and the split surface of the lower part are in a position shifted by a distance S in the horizontal direction. The positions can be aligned in the same plane as the divided bodies 14B and 14C.

Next, a method for constructing an on-site creation pile using the construction apparatus 1 described above will be described.
In constructing the site construction pile, first, as shown in FIG. 1, the work vehicle 2 equipped with the construction device 1 is moved to the site where the site construction pile is constructed, and the excavation rod 6 is in an upright state, 7, the above-described divided bodies 14 </ b> A, 14 </ b> B, 14 </ b> C are joined together, the wires 13 </ b> A, 13 </ b> B, 13 </ b> C (flexible strips) are accommodated in the excavation rod 6, and the lid 14 is opened at the lower end of the excavation rod 6. Attach to the part. (See FIG. 7A: first step)

  From here, the drive shaft of the drive head 5 is rotated in the forward direction, and the drive head 5 is moved downward while rotating the excavating rod 6 connected thereto via the driven shaft 6A. The pile holes are gradually dug by the respective excavating blades 15A, 15B, 15C. (See FIG. 7B: second step)

  During excavation in which the excavation rod 6 is rotating in the forward direction, as described above, the engaging portions 16A and 16B on the lid 14 side engage with the engaging portions 17A and 17B on the excavation rod 6 side, respectively. And the pressure due to excavation is acting on the lower surface of the lid 14 of the excavation head 7, the excavation head 7 is securely fixed to the lower end of the excavation rod 6.

  When the pile hole is excavated to the desired depth in this way, the rotation of the excavation rod 6 is stopped, and then the pile material C (eg, ready-mixed concrete) is put into the excavation rod 6 from the hopper portion 10 above the excavation rod 6 shown in FIG. To fill the inside of the hollow excavation rod 6. (See FIG. 7C: third step)

  Next, when the excavation rod 6 is lifted while rotating in the opposite direction when the required amount of pile material is filled in the excavation rod 6, the excavation head 7 receives resistance to rotation from the surrounding soil. The engagement between the engagement portions 16A and 16B on the lid body 14 side and the 17A and 17B engagement portions on the excavation rod 6 side is released.

  Then, the cover body 14 receives the weight of the pile material C in the excavation rod 6 acting on the upper surface thereof and falls off the lower end opening by the excavation rod 6, and the pile material C in the excavation rod 6 is excavated. The pile hole is discharged by its own weight and filled into the pile hole.

  On the other hand, the cover body 14 is separated into three divided bodies 14A, 14B, and 14C in the pile hole filled with the pile material C by dropping from the lower end of the excavation rod 6, but as described above, Since the divided bodies 14A, 14B, and 14C are individually connected to the bracket 11 in the excavation rod 6 by the wires 13A, 13B, and 13C, the pile material C is lifted upward as the excavation rod 6 rises. It is done. (See FIG. 7D: Fourth step)

  At this time, in the present embodiment, as described above with reference to FIG. 2, the upper ends of the three wires 13A, 13B, and 13C and the bracket 11 are connected via the rotary joint 12, Even if the excavation rod 6 rotates, the divided bodies 14A, 14B, and 14C can pass through the pile material without rotating, so that the wires 13A, 13B, and 13C can be prevented from being twisted.

Finally, the excavation head 7 divided by the ascent of the excavation rod 6 is collected on the ground, and the construction of the on-site creation pile is completed. (See FIG. 7E: Fifth step)
The excavation head 7 collected in this way is used again for construction work of another on-site creation pile.

  In the above-described embodiment, the excavation head 7 includes the lid 14 obtained by combining the three divided bodies 14A, 14B, and 14C, and the three excavating blades 15A that protrude from the lower surfaces of the divided bodies, respectively. 15B, 15C, but is not limited to the configuration of the present embodiment, the lid may be composed of two or more divided bodies, and the excavating blade is also divided into at least one What is necessary is just to be provided in the body. Further, the shapes of the divided body and the excavation blade can be appropriately changed as necessary.

  Moreover, in embodiment mentioned above, as shown in FIG.3 and FIG.4, it provided in the engaging recessed part X of the engaging parts 16A and 16B provided in the cover body 14 side of the excavation head 7, and the excavation rod 6 side. The engaging projections Y of the engaging portions 17A and 17B are engaged with each other to restrict relative rotation between them, and the fitting state is reliably maintained.

  However, these engaging portions are not limited to a structure in which the engaging concave portion X and the engaging convex portion Y are fitted to each other. For example, both the engaging portions are configured in a bowl shape and the excavation rod 6 with respect to the lid body 14 is formed. It is good also as a structure which mutually engages by forward direction rotation (rotation direction at the time of excavation), and is disengaged by reverse direction rotation.

  Further, when the excavation of the pile hole is started from the state in which the lid 14 is fitted to the excavation rod 6 and the excavation head 7 is grounded, only the relative rotation between the lid 14 and the excavation rod 6 is restricted. It is good also as a structure.

  In the above-described embodiment, as shown in FIG. 2, each of the divided bodies 14A, 14B, and 14C is rotated, and the upper ends of the three wires 13A, 13B, and 13C as flexible strips are rotated. It is connected to the bracket 11 (connecting portion) in the excavating rod 6 via the joint 12, but the flexible strip is not limited to this, and a short link chain, a resin rope having a high tensile strength, etc. It may be used.

  Further, when the wires 13A, 13B, and 13C are twisted to some extent and no trouble occurs, the rotary joint 12 may not be used. Further, the flexible strip such as a wire may be penetrated through the excavation rod and connected to the drive head by providing a connecting portion.

  The construction device and the construction method of the field construction pile of the present invention can be particularly effectively used for construction of a small diameter field construction pile that becomes a foundation pile of a small-scale house or the like.

DESCRIPTION OF SYMBOLS 1 Construction apparatus 2 Work vehicle 2A Crawler 3 Arm 4 Guide pillar 5 Drive head 5A Drive shaft 6 Excavation rod 6A Driven shaft 7 Excavation head 8A, 8B Guide sheave 9 Lifting chain 10 Hopper part 11 Bracket (connection part)
12 Rotating joint 12A One end 12B The other end 13A, 13B, 13C Wire (flexible strip)
14 Lid 14A, 14B, 14C Divided body 15A, 15B, 15C Excavation blade 16A, 16B, 17A, 17B Engagement part 18A, 18B, 18C Wire terminal fixing hole

Claims (4)

A drive head supported by the guide pillar of the work vehicle so as to be movable up and down;
A hollow excavation rod that is rotationally driven with an upper end supported by the drive head;
A construction device for an on-site creation pile comprising an excavation head detachably attached to a lower end of the excavation rod,
The excavation head is composed of a plurality of division bodies that can be combined and separated, and a lid body that is fitted in a state in which rotation is restricted to a lower end opening of the excavation rod in the combined state;
It comprises a drilling blade projecting on the lower surface of at least one divided body constituting the lid,
Each of the divided bodies is individually connected to a connecting portion provided on the inner wall surface or drive head side of the excavation rod by a flexible strip, and is united and fitted as a lid to the lower end of the excavation rod. The flexible strip is housed in a drilling rod when
By lifting the excavating rod from the ground, the lid body is detached from the lower end of the excavating rod, and the divided bodies are separated from each other, and each divided body is suspended in series below the excavating rod and collected. Construction equipment for on-site construction piles.   When the excavation rod rotates in the forward direction with respect to the lid on the position near the outer periphery of the upper surface of the lid body and the inner peripheral surface of the lower end opening of the excavation rod, it engages with each other to regulate relative rotation between the two and lower end of the excavation rod 2. The site according to claim 1, wherein a plurality of sets of engaging portions are provided that are engaged with each other and are disengaged when the excavation rod rotates in a reverse direction while maintaining a fitted state of the lid and the lid. Construction pile construction equipment.   The construction of the field construction pile according to claim 1 or 2, wherein the flexible strip is connected to the connecting portion provided on the inner wall surface of the excavating rod via a rotatable joint. apparatus. It is a method of constructing a field construction pile using the field construction pile construction device according to claim 1,
In a state where the excavation rod is in an upright state, the divided bodies constituting the lid of the excavation head are combined with each other, and after accommodating the flexible strip in the excavation rod, the lid is placed at the lower end opening of the excavation rod. A first step of mounting;
A second step of excavating the excavating rod to a predetermined depth in the ground by lowering the excavating rod in a normal direction in the excavating direction;
A third step of charging and filling the pile material into the excavation rod from its upper end side;
The excavation rod is raised while being reversed to separate the lid of the excavation head downward from the lower end of the excavation rod, and from the opened lower end of the excavation rod into the pile hole excavated in the second step. A fourth step of discharging and filling the pile material;
After the fourth step, the lower end of the excavation rod is further raised so that each of the divided bodies buried in the pile material filled in the pile hole is suspended above the excavation rod in series. A method for constructing an on-site creation pile, characterized by including a fifth step of lifting and collecting.

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