JP7025986B2 - How to build excavation buckets and cast-in-place piles - Google Patents

Description

The present invention relates to an excavation bucket attached to an excavator for drilling a hole in the ground to form a pile hole, and a method for constructing a cast-in-place pile using the excavation bucket.

Conventionally, in order to construct a cast-in-place pile, an excavator is used to rotate an excavation bucket to form a pile hole in the ground. The structure of this excavation bucket has the following configurations as described in Patent Documents 1 to 3.
Patent Document 1 discloses an excavation device including an excavation head and an excavation casing into which the excavation head is inserted. The excavation head is provided with engaging pins that protrude radially at predetermined intervals in the circumferential direction, and an engaging groove with which the engaging pins can be engaged is formed in the inner peripheral step portion of the excavation casing. There is.

Patent Document 2 describes a widening device main body detachably attached to a keriba, a widening frame provided in the widening device main body, a widening roller rotatably attached to the widening frame, and opening / closing of the widening frame. Means and pile pit widening devices for cast-in-place concrete piles consisting of means are shown.
Patent Document 3 discloses an earth drill bucket having a housing including a cylindrical body portion and a bottom plate that closes the bottom portion of the body portion, and the bottom plate is provided with a drilling blade and a side cutter. On the outside of the body, a water passage is provided to guide the stabilizing liquid that fills the upper part of the housing during excavation to the lower part of the housing.

Japanese Unexamined Patent Publication No. 5-311968 Japanese Unexamined Patent Publication No. 2001-193376 Japanese Patent Application Laid-Open No. 2003-74284

Conventionally, when the excavation bucket is rotated to form a pile hole in the ground, if there is a hard part such as a concrete block, bedrock, or boulder, the excavation bucket escapes to the soft side of the ground and the pile hole bends. There was a case that it ended up. In this case, in order to correct the bending of the pile hole, a bucket is inserted into the pile hole again and excavation is performed, and this correction excavation takes a considerable amount of time.
The present invention is a drilling bucket and cast-in-place using this excavation bucket, which can secure the verticality of the pile hole by scraping the hard part when there is a hard part in the ground and the verticality of the pile hole cannot be secured. The purpose is to provide a method of constructing piles.

The excavation bucket of the first invention (for example, the excavation bucket 1 described later) is an excavator (for example, described later) that drills a hole in the ground (for example, described later) to form a pile hole (for example, a pile hole 3 described later). An excavation bucket attached to the earth drill excavator 10) of the above, and a cylindrical body portion (for example, the body portion 20 described later) that can be attached to the lower end of the rotating shaft (for example, the Keriba 14 described later) of the excavator. A bottom plate (for example, the bottom plate 30 described later) provided with an excavation bit (for example, the excavation bit 32 described later) that closes the opening of the bottom surface of the body portion, and the outer peripheral surface of the body portion is provided with a bottom plate (for example, the bottom plate 30 described later). It is characterized in that a plurality of blades (for example, blades 40A to 40I described later) are provided in a spiral shape.

According to the present invention, since the blades are spirally provided on the outer peripheral surface of the body of the excavation bucket, the excavator rotates the excavation bucket to drill holes, and the hard part in the ground is scraped by a plurality of blades. Since it is possible to drill holes, it is possible to prevent the excavation bucket from escaping to the soft side of the ground and easily secure the verticality of the pile holes.
In addition, by providing multiple blades spirally on the outer peripheral surface of the body of the excavation bucket, when the excavation bucket is rotated to drill holes, there are hard parts such as concrete blocks, bedrock, and boulders in the ground. However, since this hard part can be drilled while being drilled with a blade, the verticality of the pile hole can be corrected accurately in a short time. Therefore, the verticality of the pile hole can be ensured, the steel pipe and the reinforcing bar cage can be reliably built in the pile hole, and the cast-in-place pile with high verticality can be easily constructed.

In the excavation bucket of the second invention, the angle of the plurality of blades is inclined so that the rotation direction side (for example, the edge 41 on the rotation direction side described later) is greatly lowered toward the batholith. It is a feature.

According to the present invention, for a plurality of blades arranged in a spiral shape, the rotation direction side is greatly lowered. Therefore, when the excavator rotates the excavation bucket to drill holes, even if there are hard parts such as rocks and gravel layers in the ground, the blades bite into these hard parts and scrape them off, making it easy to make the pile holes vertical. Can be secured.
In addition, for the plurality of blades arranged in a spiral shape, the rotation direction side is greatly lowered toward the bottom plate. Therefore, the blade on the lower end side (bottom board side) has a high downward propulsive force, and the amount of soil to be scraped off is large due to the large bite into the side wall soil. However, as the blade goes upward, the propulsive force downward becomes lower, the bite into the side wall soil of the blade becomes smaller, and the amount of soil to be scraped becomes smaller. Therefore, it is possible to scrape off hard parts such as rocks and gravel layers in the ground with the blade while keeping the rotational load of the blade as a whole low.

The method for constructing cast-in-place piles according to the third invention is a method for constructing cast-in-place piles, in which the above-mentioned excavation bucket is attached to an excavator, and the excavator rotates the excavation bucket to cut a pile hole in the ground. A step of making a hole (for example, step S1 described later), a step of building a steel pipe or a reinforcing bar cage (for example, a reinforcing bar cage 6 described later) in the pile hole (for example, step S2 described later), and a step of building the hole in the pile hole. It is characterized by comprising a step of placing concrete (for example, step S3 described later).

According to the present invention, even if there are hard parts such as concrete lumps, rocks, and boulders in the ground, the hard parts in the ground are cut with a plurality of blades by rotating the excavation bucket with an excavator to make holes. Since it is possible to drill holes, the verticality of pile holes can be corrected accurately in a short time. Therefore, the verticality of the pile hole can be ensured, the steel pipe and the reinforcing bar cage can be reliably built in the pile hole, and a cast-in-place pile with high verticality can be easily constructed.

According to the present invention, when there is a hard portion in the ground and the verticality of the pile hole cannot be ensured, the excavation bucket and the excavation bucket which can secure the verticality of the pile hole by scraping the hard portion are used. Can provide a method of constructing cast-in-place piles.

It is a side view of the excavation bucket which concerns on one Embodiment of this invention. It is a top view of the bottom surface of the excavation bucket shown in FIG. FIG. 1 is a view showing a substantially half circumference of the outer peripheral surface of the body of the excavation bucket shown in FIG. 1 and a view seen from above. It is explanatory drawing of the propulsive force generated in the blade shown in FIG. It is a side view which shows the modification of the blade shown in FIG. It is a schematic diagram which shows the operation with respect to the pile hole side wall of the excavation bucket at the time of excavation. It is a flowchart of the procedure of constructing a cast-in-place pile using the excavation bucket shown in FIG. It is explanatory drawing of the procedure for constructing a cast-in-place pile.

INDUSTRIAL APPLICABILITY According to the present invention, even in a construction site containing many concrete obstacles, bedrock, boulders, etc. in the ground, the excavation bucket has a simpler structure and can perform corrective excavation in a short time and accurately as compared with the conventional one. (FIGS. 1 to 3), and a method of constructing a cast-in-place pile using the pile hole excavation bucket (FIGS. 6 and 7). In the present invention, a plurality of blades are spirally provided on the outer peripheral surface of the cylindrical body of the excavation bucket, and the angle of the blades installed on the bottom plate side of the excavation bucket is lowered in the rotation direction side. It is characterized by an inclined point.
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a side view of the excavation bucket 1 according to the embodiment of the present invention. FIG. 2 is a looking-up view of the bottom surface of the excavation bucket 1.
The excavator bucket 1 is attached to an earth drill excavator 10 that drills holes in the ground to form pile holes. The excavation bucket 1 excavates the ground 2 to form a pile hole 3 by rotating in the direction of the white arrow in FIGS. 1 and 2 by the earth drill excavator 10.

The excavation bucket 1 includes a cylindrical body portion 20 that can be attached to the lower end of a kelly bar 14 that is a rotation axis of the earth drill excavator 10, and a disc-shaped bottom plate 30 that can be opened and closed to close the opening at the bottom surface of the body portion 20. , Equipped with.
The batholith 30 is attached to the body portion 20 so as to be openable and closable via a hinge, and by opening the batholith 30, the excavated earth and sand accumulated inside the excavation bucket 1 can be discharged.
On both sides of the center of the batholith 30, lower surface sediment intake ports 31 for taking in the sediment below the excavation bucket 1 are provided. A plurality of excavation bits 32 protruding in the rotation direction are provided side by side on the edge of each lower surface earth and sand intake port 31 on the side opposite to the rotation direction.

A joint portion 21 is provided at the upper end of the body portion 20, and the excavation bucket 1 is detachably connected to the kelly bar 14 by inserting a pin into the joint portion 21.
At two locations at the lower ends of the outer peripheral surface of the body portion 20, a side sediment intake port 22 continuously provided on the lower surface sediment intake port 31 and a side cutter 23 covering the side surface sediment intake port 22 are provided. It is provided. The side sediment intake port 22 and the side cutter 23 are for taking in the sediment on the side of the excavation bucket 1 inside.

Further, 18 blades 40A to 40I are provided on the outer peripheral surface of the body portion 20. Specifically, in a plan view, nine blades 40A to 40I are set as one set, and two sets of blades 40A to 40I are provided on opposite sides of the center of the cylindrical body portion 20 by 180 °. .. Further, a set of nine blades 40A to 40I are provided so as to spiral from the upper end toward the lower end (that is, the side surface sediment intake port 22) and project from the outer peripheral surface of the body portion 20. As described above, since the blades 40A to 40I project from the outer peripheral surface of the body portion 20, the diameter of the body portion 20 is one size smaller than the diameter W of the pile hole 3 to be excavated. Specifically, as shown in FIGS. 1 to 3, the blades 40A to 40I are substantially triangular steel plates, and the typical dimensions of the blades 40A to 40I are a thickness of about 15 mm and a body portion. The length of the side joined to 20 is about 200 mm, and the length of the side extending in the intersecting direction of the body portion 20 is about 150 mm.

FIG. 3A is a developed view of a substantially half circumference of the outer peripheral surface (side surface) of the body portion 20. FIG. 3B is a view of FIG. 3A as viewed from above. The white arrows in FIG. 3 indicate the rotation direction of the excavation bucket 1.
In a plan view, the 18 blades 40A to 40I are arranged over the entire circumference of the outer peripheral surface of the body portion 20 so as not to overlap each other. Further, in a plan view, each of the blades 40A to 40I has a substantially triangular shape, and the edge 41 on the rotation direction side is wider than the edge 42 on the side opposite to the rotation direction.
In the side view, the blades 40A to 40I are arranged so that the edge 42 on the side opposite to the rotation direction thereof has a predetermined interval d in the vertical direction. Further, in the side view, the uppermost blade 40A and the blade 40E located at the intermediate height are substantially horizontal, but the angles of the remaining seven blades 40B to 40D and 40F to 40I are inclined with respect to the horizontal plane. It is θ _B to θ _D and θ _F to θ _I. Specifically, in the blades 40F to 40I, the edge 41 on the rotation direction side is greatly lowered with respect to the edge 42 on the opposite side to the rotation direction toward the lower side (that is, the side sediment intake port 22). Further, in the blades 40B to 40D, the edge 41 on the rotation direction side is greatly raised with respect to the edge 42 on the opposite side to the rotation direction as the blades 40B to 40D are directed upward.

As shown in FIG. 4, where θ is the angle of the blade and F is the rotational force of the excavation bucket, the downward propulsion force f is expressed by the following equation.
f = F · tan θ
Since the rotational force F acting on each of the blades 40A to 40I is the same, the propulsive force f is highest for the lowermost blade 40I having a large angle θ, and decreases toward the upper side.
In the present embodiment, the blade 40I has a plate shape, but the blade 40I is not limited to this, and as shown in FIG. 5, the blade 40I closest to the batholith 30 has a substantially L shape to increase the propulsive force of the excavation bucket 1. You may do so.

FIG. 6 is a schematic view showing the operation of the excavation bucket with respect to the pile hole side wall during excavation. FIG. 6A is a case where all the blades are provided substantially horizontally, and FIG. 6B is a case where the inclination angles of all the blades are constant. In FIG. 6 (c), at the intermediate height of the body, the blade is made substantially horizontal, the inclination angle with respect to the horizontal plane is gradually increased from the intermediate height of the body to the upper side, and the angle of inclination with respect to the horizontal plane is gradually increased from the intermediate height of the body. This is the case where the tilt angle of the blade with respect to the horizontal plane is gradually increased in the opposite direction toward the lower side. In this case, the blade below the intermediate height of the body has a steeper slope than the blade above the intermediate height of the body.
In the case of FIG. 6A, even if a rotational force is applied to the excavation bucket in the direction of the white arrow in FIG. 6A to scrape off the convex portion of the side wall of the pile hole, the blade is provided substantially horizontally. Therefore, it is bounced off by the convex portion of the side wall of the pile hole, and continuous excavation is not possible. Further, in the case of FIG. 6 (b), since the inclination angle of the blade is constant, when a rotational force is applied to the excavation bucket in the direction of the white arrow in FIG. 6 (b), a downward propulsive force is generated in the excavation bucket. Since the excavation bucket naturally moves downward, it is not possible to cut the convex part of the side wall of the pile hole. Further, when a rotational force in the direction opposite to the white arrow is applied to the excavation bucket, the excavation bucket naturally moves upward, so that the convex portion of the side wall of the pile hole cannot be scraped.
On the other hand, in the present invention, as shown in FIG. 6 (c), the angle of inclination of the blade is gradually increased above the intermediate height of the body of the excavation bucket to form the excavation bucket in FIG. 6 (c). ) When a rotational force is applied in the direction of the white arrow, an upward force is generated in the excavation bucket. On the contrary, below the intermediate height of the body of the excavation bucket, a rotational force is applied to the excavation bucket in the direction of the white arrow in FIG. 6 (c) by gradually increasing the inclination angle of the blade in the opposite direction. At that time, a downward force is generated in the excavation bucket. Therefore, since the upward and downward forces generated in the excavation bucket are offset, the excavation bucket does not move unilaterally upward or downward, and the convex portion of the pile hole side wall can be scraped off by the blade provided in the excavation bucket. can.

Hereinafter, a procedure for constructing the cast-in-place pile 4 using the excavation bucket 1 will be described with reference to the flowchart of FIG. 7.
In step S1, as shown in FIG. 8A, the excavation bucket 1 is attached to the earth drill excavator 10, and the pile hole 3 is drilled in the ground 2 by the earth drill excavator 10.
Specifically, a cylindrical surface casing 5 is built in the ground 2, and an excavation bucket 1 is attached to the lower end of the keriba 14 of the earth drill excavator 10. The earth drill excavator 10 includes a swivel body 11, a boom 12, a kelly rope 13, a kelly bar 14, and the like. Next, the excavator 1 is rotated by the earth drill excavator 10, and the pile hole 3 is drilled in the ground 2 inside the surface casing 5 while injecting the stabilizing liquid.

In step S2, as shown in FIG. 8B, the reinforcing bar cage 6 is built in the pile hole 3.
In step S3, as shown in FIG. 8C, concrete is placed in the pile hole 3. Specifically, a tremie pipe 7 is built in the pile hole 3, and concrete is poured into the pile hole 3 through the tremie pipe 7. As a result, the cast-in-place pile 4 is constructed.
In step S4, as shown in FIG. 8D, the surface casing 5 is pulled out and the pile hole 3 directly above the cast-in-place pile 4 is backfilled.

According to this embodiment, there are the following effects.
(1) Since the blades 40A to 40I are spirally provided on the outer peripheral surface of the body 20 of the excavation bucket 1, a hard portion in the ground is formed by rotating the excavation bucket 1 with the earth drill excavator 10 to make a hole. Since the excavation bucket 1 can be drilled while being drilled with a plurality of blades 40A to 40I, it is possible to prevent the excavation bucket 1 from escaping to the soft side of the ground 2 and easily secure the verticality of the pile hole 3.
Further, a plurality of blades 40A to 40I are provided on the outer peripheral surface of the body portion 20 of the excavation bucket 1 so as to protrude in a spiral shape. Therefore, when the excavation bucket 1 is rotated to drill a hole, even if there is a hard part such as a concrete block, a bedrock, or a boulder in the ground, the hard part can be drilled while being drilled with the blades 40A to 40I. With the earth drill excavator 10 of the above, the verticality of the pile hole 3 can be corrected accurately in a short time without replacing the excavation bucket 1. Therefore, since the verticality of the pile hole 3 can be ensured, the reinforcing bar cage 6 can be reliably built in the pile hole 3, and the cast-in-place pile 4 having high verticality can be easily constructed.
According to the excavation bucket 1 of the present embodiment, an excavation speed 10 times higher than that in the case where the blade is not provided on the outer peripheral surface of the body portion 20 can be realized.

(2) The plurality of blades 40A to 40I arranged in a spiral shape were tilted so that the edge 41 on the rotation direction side was greatly lowered toward the bottom 30 side. Therefore, when the excavator 1 is rotated by the earth drill excavator 10 to drill a hole, even if there is a hard part such as a rock or a gravel layer in the ground, the blades 40A to 40I bite into this hard part and scrape it off. The verticality of the pile hole 3 can be easily ensured.
Further, since the blade 40I on the lower end side (bottom board side) has a high downward propulsion force f, the bite into the side wall soil becomes large, and the amount of soil to be scraped off is large. On the other hand, the upper blade has a low downward propulsion force, the bite into the side wall soil of the blade 40 becomes small, and the amount of soil to be scraped becomes small. Therefore, it is possible to scrape hard parts such as rocks and gravel layers in the ground with the blades 40A to 40I while suppressing the rotational load of the blades 40A to 40I as a whole.
(3) Since the two sets of blades 40A to 40I are provided on opposite sides by 180 °, the blades having the same angle are provided at opposite positions with the center of the body portion 20 in between, and the excavation bucket 1 is rotated. Is well-balanced and straightness is demonstrated.

The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like to the extent that the object of the present invention can be achieved are included in the present invention.

1 ... excavation bucket 2 ... ground 3 ... pile hole 4 ... cast-in-place pile 5 ... surface casing 6 ... reinforced cage 7 ... tremie pipe 10 ... earth drill excavator 11 ... swivel body 12 ... boom 13 ... kelly rope 14 ... kelly bar 20 ... Body 21 ... Joint 22 ... Side sediment intake 23 ... Side cutter 30 ... Bottom board 31 ... Bottom sediment intake 32 ... Excavation bit 40A-40I ... Blade 41 ... Edge on the rotation direction side of the blade 42 ... Blade Edge opposite to the direction of rotation

Claims (2)

An excavation bucket attached to an excavator that drills holes in the ground to form pile holes.
A cylindrical body that can be attached to the lower end of the rotating shaft of the excavator,
It is provided with a batholith that closes the opening at the bottom of the body and is provided with an excavation bit.
A plurality of blades are spirally provided on the outer peripheral surface of the body portion.
An excavation bucket characterized in that the angles of the plurality of blades are inclined so that the rotation direction side is greatly lowered toward the batholith. It is a method of constructing cast-in-place piles.
A step of attaching the excavation bucket according to claim 1 to an excavator and rotating the excavator by the excavator to drill a pile hole in the ground.
The process of building a steel pipe or reinforcing bar cage in the pile hole,
A method for constructing a cast-in-place pile, which comprises a step of placing concrete in the pile hole.

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