JP5536825B2 - Tapered pile construction method and taper pile construction casing - Google Patents

Description

  The present invention relates to a method for constructing a taper pile and a casing for taper pile construction, and the taper pile can be constructed very efficiently and easily by cast-in-place concrete.

  Tapered piles are piles formed such that the outer diameter gradually decreases from the upper end toward the lower end, and are mainly used as support piles for buildings.

  Moreover, the taper pile has the same effect as a wedge driven into the ground as compared with a pile of uniform thickness as a whole, and has a high function as a friction pile. Therefore, even if the tip does not reach a hard ground, it is said that it is suitable as a support pile of a building (see Patent Document 1).

  By the way, conventionally, this type of taper pile has been factory-produced as a steel pipe pile or a ready-made concrete pile, and there is not much construction results of taper piles by cast-in-place concrete.

  For example, in Patent Document 1, a soil cement column having a taper with a large pile head diameter is formed in the ground, and a steel pipe and a steel pipe are inserted into the soil cement column as a core material. And taper piles that are integrally connected to each other.

  Patent Document 2 discloses that the head from the upper end of the pile to the portion that receives a large lateral load, the tapered portion of the lower squeeze following this enlarged head, the pile body following this tapered portion, and the bottom of the pile tip Described is a deformed pile having a portion, and these portions are integrally formed of cast-in-place concrete.

  In Patent Document 3, a plurality of tapered piles formed so that the outer diameter gradually decreases from the upper end side toward the lower end side is press-fitted or rotationally pressed into the ground at a predetermined pitch to form a group pile. By doing so, a liquefaction countermeasure structure by group piles is described, which prevents liquefaction of the building foundation ground including the liquefied layer in particular.

JP 2001-98542 A JP 60-23520 A JP 2008-190116 A JP-A-57-81526

  In the taper pile construction method described in Patent Document 1, in particular, an auger (not shown) equipped with a mechanical or hydraulic expansion / contraction excavation head is used for excavation of the pile hole, and excavation is started with the excavation head expanded. Then, it is necessary to drill a pile hole with a taper in the hole wall by drilling to a predetermined depth while gradually reducing the drilling head, and arrange a dedicated drilling machine and a skilled operator to operate the drilling machine There was a need to do.

  Moreover, in the construction method of the taper pile described in the cited reference 2, since the pile hole is excavated while circulating the muddy water in the pile hole (reverse method), the construction tends to be large-scale. And since the steel pipe pile was used for the taper pile described in the cited reference 3, there existed a subject in terms of cost.

  The present invention has been made to solve the above problems, and an object thereof is to provide a taper pile construction method and a taper pile construction casing capable of efficiently and easily constructing a taper pile by cast-in-place concrete. It is what.

The invention according to claim 1 includes a casing main body, an eccentric casing disposed on a side portion of the casing main body, and a bottom lid that is releasably attached to a lower end portion of the casing main body, and the eccentric casing has an upper end portion. It is an invention for a taper pile construction casing characterized in that the center of the taper is eccentric with respect to the center of the casing main body and gradually approaches the center of the casing main body as it moves in the lower end direction. .

Invention of Claim 2 is invention of the construction method of the taper pile which constructs a taper pile by the taper pile construction casing of Claim 1 , and pushes it in the ground, rotating the said pile construction casing around the axis | shaft A step of charging concrete or mortar into the pile construction casing, and gradually discharging the concrete or mortar while discharging the concrete or mortar into a pile hole formed by pulling out the pile construction casing. It is invention of the construction method of a taper pile characterized by consisting of the process pulled out to.

The invention according to claim 3 is a method for forming a pile construction casing comprising a casing main body and a bottom lid releasably attached to a lower end portion of the casing main body while tilting the lower end portion as a fulcrum and turning the upper end side to the ground. A step of pushing, a step of putting concrete or mortar into the casing for pile construction, and a casing for pile construction while discharging the concrete or mortar into a pile hole formed by pulling out the casing for pile construction. It is invention of the construction method of a taper pile characterized by consisting of the process of pulling out gradually.

  In the present invention, when a tapered pile is constructed by cast-in-place concrete, it is possible to easily form a pile hole having a taper in the hole wall, and particularly suitable for the construction of a tapered pile on soft ground. Yes.

  That is, according to the present invention, a pile construction casing having a taper is easily formed by pushing a casing for pile construction in a vertical or slightly inclined state and pushing it into the ground while rotating or turning around a vertical axis. be able to.

  In addition, while gradually pulling out the pile construction casing from the ground, by discharging concrete or mortar in the casing to the pile hole that is formed afterwards, a series of continuous formation of pile holes and concrete or mortar placement By performing as a process, the taper pile can be constructed very efficiently.

  Moreover, according to the casing for taper pile construction of Claims 1 and 2, by changing the length of a taper casing and an eccentric casing suitably, over the full length of the head-expanded pile and pile which have a taper partially in the vicinity of a pile head A cast-in-place concrete pile with a taper can be easily constructed.

  For example, in the case of a pile head pile having a taper partially in the vicinity of the pile head, although depending on the length of the pile, the taper length of about 75 cm to 100 cm is desirable when the total length of the pile is about 9 m to 10 m. Further, the amount of eccentricity α at the upper end portion of the eccentric casing relative to the casing body may be about 3 to 5 cm horizontally (see FIG. 7 (a)).

  The outer diameter of the casing body and the eccentric casing may be the same, or the casing body may be larger in diameter than the eccentric casing.

  Further, a plurality of reinforcing ribs may be attached between the casing body and the taper casing and between the casing body and the eccentric casing for reinforcement (see FIGS. 3 and 7).

  Further, in the taper pile construction method according to claim 4, the inclination of the taper can be arbitrarily set by adjusting the inclination of the casing, and is usually horizontal to the vertical axis at the upper end of the casing. It is sufficient to incline about α = 3 to 5 cm.

  Also, the casing can be pushed into the ground while turning the casing by slightly moving the leader back and forth and right and left while operating the auger motor to rotate the case sink. Furthermore, you may attach the attachment which transmits rotation of a drive shaft to the upper end part of a casing as a turning motion to the drive shaft of an auger motor.

  In addition, any pile construction casing is a construction heavy machine equipped with a vertically extending leader and an auger motor that is guided by the leader, and is installed and used on existing construction heavy equipment such as pile driving machines and earth augers. be able to. Furthermore, any pile construction casing can be easily manufactured using an existing steel pipe.

  According to the present invention, it is possible to easily excavate a pile hole having a taper in the hole wall, and thus, it is possible to efficiently and easily build a tapered pile with cast-in-place concrete. Moreover, the casing for pile construction is extremely economical because it can be used repeatedly.

It is a side view which shows the state which installed the casing used for construction of a taper pile in construction heavy machinery. It is a longitudinal cross-sectional view of the lower end part of the casing illustrated in FIG. (A), (b) shows the casing illustrated in FIG. 1, and is a cross sectional view taken along the line II and the roll line in FIG. 1, respectively. (A)-(c) is a perspective view which shows the construction procedure which constructs a taper pile by the casing illustrated in FIG. (A)-(c) is a perspective view which shows the construction procedure which constructs a taper pile by the casing illustrated in FIG. It is a side view which shows the state which installed the casing used for construction of a taper pile in construction heavy machinery. (A), (b) shows the casing illustrated in FIG. 6, and is a cross sectional view taken along the line II and the roll line in FIG. 6, respectively. (A)-(c) is a perspective view which shows the construction procedure which constructs a taper pile by the casing illustrated in FIG. (A)-(c) is a perspective view which shows the construction procedure which constructs a taper pile by the casing illustrated in FIG. It is a side view which shows the state which installed the casing used for construction of a taper pile in construction heavy machinery. It is a longitudinal cross-sectional view of the lower end part of the casing illustrated in FIG. (A)-(c) is a perspective view which shows the construction procedure which constructs a taper pile by the casing illustrated in FIG. (A)-(c) is a perspective view which shows the construction procedure which constructs a taper pile by the casing illustrated in FIG.

  1 to 5 show an embodiment of the present invention, FIGS. 1 to 3 show a taper pile construction casing (hereinafter referred to as “casing”) used for construction of a taper pile, and FIGS. 4 and 5 show taper piles. The construction procedure is illustrated.

  In the figure, a casing 1 includes a casing body 2, a large-diameter casing 3 and a tapered casing 4 disposed above the casing body 2, a bottom lid 5 attached to a lower end portion of the casing body 2, and a plurality of excavation bits. 6 respectively.

  The large-diameter casing 3 is formed in a cylindrical shape that is slightly larger than the casing main body 2, and is arranged concentrically with the casing main body 2 in a plan view above the casing main body 2.

  The tapered casing 4 is formed such that the outer diameter of the upper end portion is larger than the outer diameter of the casing body 2 and the same diameter as the outer diameter of the large-diameter casing 3, and gradually increases to the outer diameter of the casing body 2 as it moves downward. Asymptotically, it is formed in a cross-sectional shape that matches the outer diameter of the casing body 2 at the lower end.

  In other words, the outer peripheral surface of the tapered casing 4 is formed in a tapered surface shape whose diameter gradually decreases from the upper end to the lower end. Further, the tapered casing 4 is integrally continuous with the large-diameter casing 3 below the large-diameter casing 3 and is concentrically arranged when viewed from the plane with the casing body 2.

  A plurality of reinforcing ribs 3a and 4a are radially attached between the casing body 2, the large-diameter casing 3 and the tapered casing 4 (see FIGS. 3 (a) and 3 (b)).

  The casing body 2 and the large-diameter casing are formed from steel pipes, and the tapered casing 4 is formed from a tapered steel pipe. Further, the reinforcing ribs 3a and 4a may be vertical ribs continuous in the tube axis direction of the casing or horizontal ribs continuous in the direction perpendicular to the tube axis of the casing.

  The bottom cover 5 is formed to have substantially the same diameter as the outer diameter of the casing body 2, and is opened only below the casing body 2 by being pivotally supported in the vertical direction at the peripheral edge of the lower end portion of the casing body 2. It is attached so as not to open above (inward).

  Two to four excavation bits 6 are attached to the outer peripheral portion of the lower end portion of the casing body 2 in the circumferential direction of the canning body 2 at substantially equal intervals. Further, the excavation bit 6 is attached in a state in which the cutting edge 6 a at the tip protrudes slightly from the lower end portion of the casing body 2.

  The casing 1 thus configured is a heavy construction machine such as a pile driving machine or an earth auger, and is installed and used in a heavy construction machine 9 having a vertically extending leader 7 and an auger motor 8 which is guided by the leader 7 and moves up and down. Is done.

  Next, a method for constructing a taper pile using the casing 1 will be described (see FIGS. 4 and 5).

(1) First, the casing 1 is installed on the heavy construction machine 9 at the point where the taper pile is to be constructed, and is set up vertically. In this case, the casing 1 is vertically laid on the point where the tapered pile is constructed along the leader 7 of the heavy construction machine 9. Then, the upper end portion of the casing 1 is connected to the auger motor 8 via the YATCO 10.

(2) Next, the pile hole A is formed by operating the auger motor 8 and gradually pushing it into the ground while rotating the casing 1. A portion of the fixed depth from the ground of the pile hole A is formed to be larger than the outer diameter of the casing body 2 by being uniformly spread by the large diameter casing 3, and a portion of the constant depth deeper than this is formed by the tapered casing 4. By being spread evenly, the upper end portion is wide and is formed into a tapered pile hole that becomes gradually narrower as it gets deeper.

  While the excavation hole A is formed by the casing 1, excavation soil does not enter the casing 1 because the lower end portion of the casing 1 is closed by the bottom cover 5.

(3) Next, when the pile hole A reaches a predetermined depth, the upper end of the casing 1 is temporarily separated from the auger motor 8. Then, reinforcing bars B are arranged in the casing 1 and then concrete C is filled.

  The reinforcing bar B can be efficiently arranged by arranging bars assembled in a basket shape. In addition, it is desirable to use concrete or mortar having high fluidity for the concrete C because the concrete filling property is improved.

(4) Next, the upper end portion of the casing 1 is connected to the auger motor 8 again through the yatco 10. Then, the auger motor 8 is actuated to gradually lift the casing 1 while rotating it.

  Then, the bottom cover 5 opens downward by the weight of the reinforcing bar B and the concrete C in the casing 1, and at the same time, the reinforcing bar B in the casing 1 is discharged from the lower end portion of the casing body 2 into the pile hole A and the pile hole A. The bars are arranged vertically inside. At the same time, the concrete C in the casing 1 is discharged from the lower end portion of the casing body 2 into the pile hole A and filled into the pile hole A.

  In addition, when pulling out the casing 1, the concrete can be uniformly and densely filled into the pile hole A by applying vibration to the concrete C through the casing 1.

  The bottom lid 5 is attached to the lower end portion of the casing body 2 with an adhesive tape or the like so as to be easily dropped by the weight of the concrete C, and is embedded in the pile hole A together with the concrete C when the concrete C is placed. You may make it do.

  With the above construction procedure, the taper pile D is constructed very efficiently and easily by cast-in-place concrete, with the formation of the pile hole A, the reinforcement bar B placement and the concrete C placement as a series of continuous processes. Can do. Moreover, the casing 1 can be constructed economically because it can be used repeatedly.

  FIGS. 6 to 9 also show an embodiment of the present invention, FIGS. 6 and 7 show a pile construction casing (hereinafter referred to as “casing”) used for construction of tapered piles, and FIGS. 8 and 9 show tapered piles. The construction procedure is illustrated. In the figure, the same members as those shown in FIGS. 1 to 5 having the same configuration are denoted by the same reference numerals and description thereof is omitted.

  The casing 11 includes a casing main body 2, an eccentric casing 12 disposed above the casing main body 2, a bottom lid 5 attached to a lower end portion of the casing main body 2, and a plurality of excavation bits 6.

  The center of the upper end of the eccentric casing 12 is decentered about α = 3 to 5 cm horizontally with respect to the center of the casing body 2 and gradually approaches the center of the casing body 2 as it moves downward. The cross section is formed so as to coincide with the center of the main body 2. That is, the outer peripheral surface of the eccentric casing 12 is formed in a tapered surface shape whose diameter gradually decreases from the upper end toward the lower end.

  A plurality of reinforcing ribs 12a are radially attached between the casing body 2 and the eccentric casing 12 (see FIGS. 7A and 7B). The reinforcing rib 12a may be a vertical rib or a horizontal rib.

  The eccentric casing 12 can be formed by, for example, a method in which a steel pipe having a certain length is cut obliquely in the pipe axis direction, and one of them is welded and attached to the side surface of the casing body 2. The casing 11 formed in this way is used by being installed in the heavy construction machine 9.

  Next, a method for constructing a tapered pile using the casing 11 will be described (see FIGS. 7 and 8).

(1) First, the casing 11 is installed on the heavy construction machine 9 at the point where the tapered pile is to be constructed, and is vertically erected. In this case, the casing 11 is set up vertically at a point where the tapered pile is constructed along the leader 7 of the heavy construction machine 9. Then, the upper end portion of the casing 11 is connected to the auger motor 8 via the YATCO 10.

(2) Next, the auger motor 8 is operated to push the casing 11 into the ground while rotating the casing 11 to form the pile hole A. The part of the fixed depth close to the ground of the pile hole A becomes a piled hole with a taper that becomes wider and narrows gradually as the upper end part is widened by being evenly spread by the rotating eccentric casing 12.

(3) When the pile hole A reaches a predetermined depth, next, the upper end of the casing 11 is temporarily disconnected from the auger motor 8, the reinforcing bar B is placed in the casing 11, and then the concrete C is filled. .

(4) Next, the upper end portion of the casing 11 is connected to the auger motor 8 again through the yatco 10. Then, the auger motor 8 is operated to gradually lift the casing 11 while rotating it. Then, the bottom lid 5 is opened downward by the weight of the reinforcing bar B and the concrete C in the casing 11, and at the same time, the reinforcing bar B in the casing 11 is discharged from the lower end portion of the casing body 2 into the pile hole A and the pile hole A. The bars are arranged vertically inside. At the same time, the concrete C in the casing 11 is discharged from the lower end portion of the casing body 2 into the pile hole A and filled into the pile hole A.

  In addition, when pulling out the casing 11, the concrete can be uniformly and densely filled into the pile hole A by applying vibration to the concrete C through the casing 11.

  With the above construction procedure, the formation of the pile hole A, the reinforcement bar B placement and the concrete C placement is a series of continuous processes, and the taper pile D having a taper near the ground surface by cast-in-place concrete is very efficient. And it can be easily constructed.

  FIGS. 10 to 13 also show an embodiment of the present invention, FIGS. 10 and 11 show a pile construction casing (hereinafter referred to as “casing”) used for construction of tapered piles, and FIGS. 12 and 13 show tapered piles. The construction procedure is illustrated. In the figure, the same members as those shown in FIGS. 1 to 5 having the same configuration are denoted by the same reference numerals and description thereof is omitted.

  In the figure, the casing 13 is configured by attaching a bottom lid 5 and a plurality of excavation bits 6 to the lower end of the casing body 2.

  The casing 13 is a construction heavy machine such as a pile driving machine or an earth auger, which is installed and used in a heavy construction machine 9 having a vertically extending leader 7 and an auger motor 8 that is guided by the leader 7 and moves up and down.

  Next, a method for constructing a tapered pile using the casing 13 in such a configuration will be described (see FIGS. 12 and 13).

(1) First, install the casing 13 on the heavy construction machine 9 at the point where the taper pile is to be constructed. In this case, the casing 13 is placed along the leader 7 of the heavy construction machine 9 at a point where the taper pile is to be constructed and tilted slightly. Then, the upper end portion of the casing 13 is connected to the auger motor 8 via the yatco 10.

(2) Next, the auger motor 8 is operated to rotate the casing 13 and form a pile hole A by pushing it into the ground. In this case, it is possible to push the casing 13 into the ground while turning the casing 13 by slightly moving the leader 7 back and forth and right and left while rotating the case sink 13 by operating the auger motor 8.

  As a result, the casing 13 is pushed into the ground so that the upper end turns in a plane circular shape with the lower end inclined slightly with respect to the fulcrum. Further, the ground is excavated by the excavation bit 6 attached to the lower end portion of the casing body 2, and the pile hole A is formed by the casing 13 gradually sinking in the ground along with this.

  Moreover, the hole wall of the pile hole A is uniformly expanded by the peripheral wall of the casing 13, so that the pile hole A is formed into a tapered pile hole gradually narrowing as the upper end portion becomes wider and deeper.

  During excavation of the excavation hole A by the casing 13, the lower end portion of the casing 13 is blocked by the bottom cover 5, so that excavation soil does not enter the casing 13.

(3) Next, when the pile hole A reaches a predetermined depth, the upper end portion of the casing 13 is temporarily disconnected from the auger motor 8 and the casing 13 is stood vertically. Then, reinforcing bars B are arranged in the casing 13 and then concrete C is filled.

(4) Next, the upper end portion of the casing 13 is connected again to the auger motor 8 via the yatco 10. Then, the auger motor 8 is actuated to gradually lift the casing 13 while rotating it.

  Then, the bottom cover 5 is opened downward by the weight of the reinforcing bar B and the concrete C in the casing 13, and at the same time, the reinforcing bar B in the casing 13 is discharged from the lower end portion of the casing body 2 into the pile hole A. The bars are arranged vertically inside. At the same time, the concrete C in the casing 13 is discharged from the lower end portion of the casing body 2 into the pile hole A and filled into the pile hole A.

  Note that when the casing 13 is pulled out, the concrete can be uniformly and densely filled into the pile hole A by applying vibration to the concrete C through the casing 13.

  With the above construction procedure, excavation of the pile hole A, reinforcement reinforcement B and concrete C placement is a series of continuous processes, and taper pile D is constructed extremely efficiently and easily by cast-in-place concrete. Can do. The casing 13 can be economically constructed because it can be used repeatedly.

  In the present invention, a taper pile used as a support pile of a building can be constructed very efficiently and easily by cast-in-place concrete.

1 Casing (casing for taper pile construction)
2 Casing body 3 Large diameter casing 3a Reinforcing rib 4 Tapered casing 4a Reinforcing rib 5 Bottom lid 6 Drilling bit 7 Leader 8 Auger motor 9 Construction heavy machine 10 Yatco 11 Casing (casing for taper pile construction)
12 Eccentric casing 12a Reinforcing rib 13 Casing (Taper pile casing)
A Drilling hole B Reinforcing bar C Concrete D Tapered pile

Claims (3)

  A casing body, an eccentric casing disposed on a side portion of the casing body, and a bottom lid that is releasably attached to a lower end portion of the casing body, wherein the center of the upper end portion of the eccentric casing is the center of the casing body. The taper pile casing is characterized in that it is formed so as to be gradually asymptotic to the center of the casing body as it shifts in the lower end direction. A taper pile construction method for constructing a taper pile by the taper pile construction casing according to claim 1 , wherein the pile construction casing is pushed into the ground while rotating around the axis of the pile construction, and the pile construction casing includes concrete. Alternatively, the method comprises a step of feeding mortar and a step of gradually pulling out the casing for pile construction while discharging the concrete or mortar into a pile hole formed by pulling out the casing for pile construction. Tapered pile construction method.   A step of pushing a casing for pile construction consisting of a casing main body and a bottom lid releasably attached to the lower end portion of the casing main body into the ground while tilting the lower end portion as a fulcrum and turning the upper end side; A step of putting concrete or mortar into the casing, and a step of gradually pulling out the casing for pile construction while discharging the concrete or mortar into a pile hole formed by pulling out the casing for pile construction. A taper pile construction method characterized by

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