JP2850073B2 - Pile frame widening device for cast-in-place concrete piles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for widening a pile body of a cast-in-place concrete pile.

[0002]

2. Description of the Related Art Hitherto, in order to increase the supporting force of a cast-in-place concrete pile, a method of widening the tip of the pile has been adopted. During widening, the entire frusto-conical shape is excavated, requiring a large torque. In this case, the pile hole for forming the pile frame portion is excavated to a predetermined depth by using an excavation bucket, and thereafter, the widening excavation-dedicated machine and the dedicated expanded bottoming excavation bucket are replaced with a normal excavation bucket to widen the width.

Further, a stabilizer is attached to the bottom-extended excavation bucket, and the stabilizer is used to determine the excavation accuracy of the bottom-extended portion.

[0004]

However, widening and excavating the pile bottom requires a large rotating torque.
A dedicated drilling machine and a dedicated bottoming drilling bucket are required, and the bottoming pile is formed in a frusto-conical shape with a large bottom area. As the confining pressure decreases and the pile diameter increases, so does the amount of settlement. The excavation shape depends on the shape of the dedicated bottom-excavation bucket. In addition, the bearing capacity of the expanded pile is determined only by the cross-sectional area of the expanded part.

The present invention has been made in view of the above problems, and has as its object to improve the workability with a simple structure and to effectively increase the bearing capacity of a cast-in-place concrete pile. Therefore, it is an object of the present invention to provide a pile frame widening device for a cast-in-place concrete pile capable of controlling the amount of settlement at the pile head.

[0006]

In order to achieve the above-mentioned object, a pile body widening device for a cast-in-place concrete pile according to the present invention comprises a rotary excavation above a drill bucket mounted on the tip of a rotary excavation shaft. A widening device mounted on an upper part of the shaft and functioning as a stabilizer during operation of the excavating bucket. The widening device includes a plurality of scrapers pivotally supported so as to be openable and closable, and an opening / closing drive member for each of the scrapers. Each of the scrapers is formed in a hollow shape with open upper and lower surfaces, and has an outer peripheral surface formed in a crescent shape along the wall of the excavation hole.

[0007]

The widening device of the pile body according to the present invention has the widening device mounted above the rotary digging shaft above the digging bucket mounted on the tip of the rotary digging shaft as described above. Performs the stabilizer function of the excavation bucket, the vertical excavation accuracy is increased, and during widening excavation,
The digging bucket performs the stabilizer function of the widening device, and the digging accuracy in the horizontal direction is improved.

At the time of widening excavation, the scraper of the widening device is opened by the opening / closing drive member to perform widening excavation. At this time, claw marks remain on the hole wall surface due to the excavation bit provided at the tip of the scraper. This claw mark is reversed by turning the whole device in reverse and pressing the excavated surface with the lunar body of the scraper, as if plasterer presses down the wall with a plasterer iron, and erases it, leaving no claw marks remaining smooth Finish on the excavated surface. By this finishing, the arching action of the excavated surface is improved, and the excavated shape is further stabilized. Normally, the hole wall surface where the nail mark remains has irregularities, and if there is irregularity, the soil is easily peeled off, and if peeled off, the stability of the hole wall becomes poor, and the peeled soil becomes a cause of slime generation, When it is pressed down and kneaded (kneaded) many times with the body of the scraper as described above, it is prevented from peeling off, the excavation shape is stabilized, and the peripheral strength of the pile is increased. If the scraper has a forward rotation and a reverse rotation, the forward rotation scraper is opened, and the widening excavation is performed by the drilling bit provided at the tip thereof. And are performed simultaneously.

Since the scraper is formed in a hollow shape with open upper and lower ends, when the drilling bucket moves up and down in the drilling hole, it can be constructed in the same state as the conventional earth drilling method. In addition, earth and sand removed by widening usually floats easily in muddy water, but when digging with a moon-shaped scraper right above the digging bucket, it is quickly accumulated in the digging bucket immediately below, preventing the generation of slime. .

[0010] When the predetermined widening is completed, the scraper of the widening device is closed, and the earth and sand in the excavating bucket is discharged to the ground. In addition, when building the next-order node part in a pillar body, the said process is repeated. When forming a corrugated pile having a large pile surface frictional resistance, the scraper may be replaced with a corrugated scraper.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of the present invention will be described with reference to the drawings. A
Reference numeral denotes an excavating bucket mounted on the tip of the rotary excavating shaft 1, and reference numeral 2 denotes a bottom cover opening and closing device of the excavating bucket A. On the rotary excavating shaft 1 above the excavating bucket A, a widening device B for pile body is mounted, and a lower part of the widening device B is a free rotary joint 3.
Is connected to the excavating bucket A via C in the figure is a hydraulic hose.

The widening device B performs widening excavation as described later. At that time, the excavating bucket A performs a stabilizer function with respect to the widening device B. In the widening device B, the base ends of the forward and reverse scrapers 4, 4 'are pivotally supported at the respective distal ends of a cross-shaped rigid frame B' via pins 5, 5 'so as to be openable and closable. I have. These scrapers 4, 4 'are formed in a hollow shape with open upper and lower surfaces, and the outer peripheral surface is formed in a crescent shape along the wall of the excavation hole. Drilling bits 4a, 4'a are provided at the tips of the scrapers 4, 4 ', and a hydraulic cylinder 6 for normal rotation is provided between the plate-shaped earth and sand guide plates 4b, 4'b and the frame B'. And a hydraulic cylinder 6 'for reverse rotation are interposed. These hydraulic cylinders 6, 6 'correspond to opening and closing driving members of the scrapers 4, 4'.

Since the illustrated embodiment is constructed as described above, the rotary excavating shaft 1 is rotated to excavate a pile hole by the excavation bucket A, and during the excavation of the pile hole, the widening device B is operated by the excavation bucket. Performs a stabilizer function for A. When the widened joint portion Q of the pile body P is excavated, when a predetermined depth is reached, the scraper 4 constituting the outer frame of the widening device B is opened around the pin 5 via the hydraulic cylinder 6 ', and the rotary excavation is performed. The shaft 1 is reversed to form the widened joint Q.

The scrapers 4, 4 'can be replaced. If necessary, the pile peripheral surface can be replaced by a corrugated scraper in accordance with the shape required for the pile peripheral surface. It is possible to build corrugated piles that have been done.
In the construction of the corrugated pile, the excavation bucket A is reversed or the excavation in the depth direction is stopped via the free rotation joint 3. The excavated earth and sand at the widening section Q is
While moving to the center of the pile axis along the guide plates 4b, 4'b of the scrapers 4, 4 ', they are accumulated in the lower excavation bucket A.

The earth and sand accumulated in the excavating bucket A is discharged to the ground by closing the scrapers 4, 4 'by the hydraulic cylinders 6, 6'. If another widened joint is formed, the above steps may be repeated. When the bottom of the pile body P is a continuous widened portion, the excavating bucket A and the widening device B are simultaneously rotated in the forward direction, and the excavating bucket A is replaced with a bottom dredge at the lowermost part. Can be constructed well.

In the excavation in this case, since the excavation bucket A and the widening device B function as a stabilizer of the partner device, excavation accuracy is ensured. 5 to 7 show various excavation situations of the pile body widening device for the cast-in-place concrete pile. That is, FIG. 5 shows a state of excavation of the pile skeleton. The rotary excavation shaft 1 rotates forward, and the widening device B and the excavation bucket A in which the excavation blade is in an inoperative state also rotate forward.

FIG. 6 shows a state of excavation of the knot pile, in which the rotary excavating shaft 1, the widening device B in the operating state is reversely rotated, and the excavating bucket A is reversely rotated or stationary. FIG. 7 shows the state of excavation of the widened columnar pile, in which the rotary excavating shaft 1 rotates forward, the operating widening device B rotates forward, and the excavating bucket A rotates forward. FIG. 8 to FIG. 14 show various piles constructed by the pile-widening device for the cast-in-place concrete pile. 8 is a corrugated pile, FIG. 9 is a pile formed with an expanded bottom at the bottom of the corrugated pile, FIG. 10 is a piling dedicated pile having an inverted conical bottom, FIG. 11 is an expanded pile, FIG. FIG. 13 shows a long expanded bottom pile.
FIG. 14 shows a pier 1 column stake in which a flat disk-shaped portion is formed near the pile head.

In the illustrated embodiment, the excavating bucket A and the widening device B are vertically separated from each other, but they may be integrated.

[0019]

As described above, according to the present invention, the widening device is mounted above the rotary digging shaft above the digging bucket mounted at the tip of the rotary digging shaft. During widening excavation, the excavating bucket performs the stabilizer function of the widening device, so that the pile hole for cast-in-place pile formation can be accurately excavated. Since the widening length is a partial excavation, a large rotating torque is not required.

Further, according to the present invention, a knot pile and a corrugated pile having a large bearing strength can be formed, and by expanding the bottom of the pile skeleton, a pile tip strength equivalent to the widening of the pile is expected, and Large pile surface resistance can be expected with the widening of the pile body. Also, by expanding the width above the bottom of the pile, it is possible to disperse the upper stress at the bottom of the pile,
The amount of settlement at the pile head can be controlled.

When the upper part of the pile body is locally widened, the bending moment due to the upper structure of the pile is not exerted on the pile body,
Reasonable and economical design is possible. When the scraper of the widening device is replaced, a corrugated pile having a widened pile surface in a wavy shape can be constructed, and a large peripheral friction force can be obtained. Furthermore, since the widening device is located above the excavation bucket, the soil quality of the widened part can be easily checked by looking at the soil in the excavation bucket to be pre-drilled, enabling more reliable widening of the pile frame. Become.

Further, since the load surface acts on the upper surface from the pile bottom, the support layer may be a thin layer, and the width can be easily widened.
The amount of pile settlement and bearing capacity can be easily controlled. Further, at the time of widening excavation, the scraper of the widening device is opened by the opening / closing drive member to perform widening excavation. At this time, a claw mark remains on the hole wall surface due to the excavation bit provided at the tip of the scraper. This claw trace is reversed by turning the entire device in reverse and pressing the excavated surface with the lunar body of the scraper, as if the plasterer presses down the wall with a plastering iron, erasing it without any claw traces. Finish on the surface. With this finish,
The arching effect of the excavated surface can be improved, and the excavated shape can be further stabilized.

Further, since the scraper has a hollow shape in which both the upper and lower surfaces are open, when the drilling bucket moves up and down in the drilling hole, it can be constructed in the same state as the conventional earth drilling method. In addition, although the earth and sand removed by the widening is usually easily suspended in muddy water, the excavation by the moon-shaped scraper immediately above the excavation bucket can quickly accumulate in the excavation bucket immediately below, thereby preventing the generation of slime.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of a pile body widening device for a cast-in-place concrete pile of the present invention.

FIG. 2 is a cross-sectional plan view of the pile body widening device.

FIG. 3 is a front view showing a construction state of a node portion by the pile body widening device.

FIG. 4 is a cross-sectional plan view of the pile body widening device.

FIG. 5 is an explanatory diagram showing a state of excavation of a pile skeleton by a pile skeleton widening device.

FIG. 6 is an explanatory view showing a state of excavation of a knotted pile by the pile body widening device.

FIG. 7 is an explanatory diagram showing a state of excavation of a widened columnar body by a pile body widening device.

FIG. 8 is a longitudinal sectional view showing a corrugated pile constructed by a pile body widening device.

FIG. 9 is a vertical cross-sectional view showing a composite pile of a corrugated pile and an expanded bottom pile constructed by a pile body widening device.

FIG. 10 is a longitudinal sectional view showing a drawing-only pile constructed by the pile body widening device.

FIG. 11 is a longitudinal sectional view showing an enlarged pile pile constructed by the pile frame widening device.

FIG. 12 is a longitudinal sectional view showing a knotted pile constructed by the pile body widening device.

FIG. 13 is a longitudinal sectional view showing a long expanded bottom pile constructed by the pile body widening device.

FIG. 14 is a longitudinal sectional view showing a pile locally widened at an upper portion of a pile skeleton constructed by the pile skeleton expanding device.

[Explanation of symbols]

 Reference Signs List A excavating bucket B pile body widening device B 'frame C hydraulic hose P pile body Q widening joint 1 rotary excavating shaft 2 bottom lid opening and closing device 3 free rotating joint 4, 4' scraper 4a, 4'a drill bit 4b, 4b 'B Guide plate 5, 5' Pin 6, 6 'Opening / closing drive member (hydraulic cylinder)

Claims (1)

(57) [Claims] 1. A widening device which is mounted on an upper portion of a rotary digging shaft above a digging bucket mounted on a tip portion of a rotary digging shaft and functions as a stabilizer during operation of the digging bucket. Each of the scrapers is pivotally supported so as to be openable and closable, and each of the scrapers is provided with an opening / closing drive member. A pile frame widening device for cast-in-place concrete piles characterized by being formed in a moon shape.