JP3752610B2 - Expanded excavation method and expanded excavator for cast-in-place concrete pile with rib - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the field of technology for constructing cast-in-place concrete piles, in particular, multistage expanded piles (hereinafter referred to as ribbed cast-in-place concrete piles) that increase the pulling resistance or support force. The present invention relates to a method for expanding a diameter portion of a cast-in-place concrete pile and a diameter expanding excavator used for carrying out the method.
[0002]
[Prior art]
Conventionally, an earth drill method has been often used as a drilling method for cast-in-place concrete piles.
Conventionally, cast-in-place concrete piles with ribs that increase the pulling resistance or supporting force of cast-in-place concrete piles are also known and practiced. For example,
(1) In JP-A-1-190818, pile holes are excavated by a screw auger and multi-stage ribs are expanded, and solidified material is mixed with excavated soil once discharged to the ground. A method and excavator for refilling and building a ribbed cast-in-place concrete pile is disclosed.
{Circle around (2)} Japanese Laid-Open Patent Publication No. 4-265212 discloses a method for constructing a cast-in-place concrete pile with ribs in which a plurality of bottoms are formed so as to utilize the supporting force of a plurality of formations.
(3) Japanese Laid-Open Patent Publication No. 7-145616 also discloses a method for constructing multi-stage ribbed cast-in-place concrete piles.
[0003]
When performing the diameter expansion excavation of the rib portion of the above-mentioned ribbed cast-in-place concrete pile, excavation by various types of diameter expansion bits is performed.
[0004]
[Problems to be solved by the present invention]
In the case of performing diameter expansion excavation of the rib part of a cast-in-place concrete pile with ribs with a conventional general diameter expansion bit, it is suitable for diameter expansion excavation at the hole bottom because it is a structure where a stabilizer is installed above the diameter expansion bit, In the case of diameter-expanded excavation at the middle part of the shaft hole, it is difficult to obtain a circular shape concentric with the shaft hole because the shaft core of the diameter-enlarged bit cannot be fixed and the diameter-enlarged portion is eccentric. There is also a problem that the expanded surface is liable to collapse.
[0005]
In the case of the above construction method (3), a stabilizer is installed below the enlarged-diameter excavation section, but on the contrary, no stabilizer is provided on the upper side, and the shaft core is fixed above and below the enlarged-diameter excavation section. Since it is not a structure, the shaft core of the diameter-expanding bit cannot be fixed, and the drilled diameter-expanded portion is eccentric, making it difficult to obtain a circular shape concentric with the shaft hole. As a result, the width of the rib portion becomes non-uniform in the circumferential direction, and eventually the rate of increase in pulling resistance force by the rib is reduced.
[0006]
Moreover, it is difficult to adjust the diameter expansion pitch because it is a diameter expansion excavation work in muddy water. Furthermore, since the support point is suspended from the crane, the vertical movement is likely to occur, and it is difficult to obtain a predetermined expanded diameter shape. In addition, in all of the conventional techniques, the excavated earth and sand are allowed to settle to the bottom of the hole, and when the bottom is prepared, the bottom and middle hole wall surfaces of the hole are formed by repeated vertical movement of the slime treatment bucket. May cause damage or collapse.
[0007]
Accordingly, an object of the present invention is to use a Kelly bar shaft or the like whose vertical drive shaft is fixed to the center of the hole bottom of the hole for a pile (shaft hole) and whose upper portion is supported with high vertical accuracy by a base machine or the like. Using a diameter expansion excavator whose diameter expansion excavation mechanism moves up and down along the axis, the diameter expansion excavation can be performed at any intermediate position (height) of the shaft hole, and the Kelly bar shaft is centered. As a result, it is possible to drill the diameter-expanded part (rib part) concentric with the shaft hole with high precision, and to store the excavated earth and sand in a bucket at the bottom of the hole immediately after excavation. By providing a method for expanding the diameter of the rib part of a cast-in-place concrete pile with ribs and an expanded excavator used for carrying out the method, which can be transported to the ground and improved so as to greatly reduce the labor of slime treatment. is there.
[0008]
[Means for Solving the Problems]
As a means for solving the above problems, a method for expanding the diameter of a cast-in-place concrete pile with a rib according to the invention of claim 1 is as follows:
After completing the drilling of the shaft hole of the cast-in-place concrete pile, attach the shaft core fixing and excavating earth and sand collection bucket to the tip of the vertical drive shaft such as the kelly bar shaft of the earth drill, and the middle part of the vertical drive shaft A diameter expansion excavator equipped with a diameter expansion excavation mechanism is inserted into the shaft core fixing and excavating earth and sand collection bucket to the bottom of the shaft hole portion to fix the axis of the vertical drive shaft, Thereafter, the enlarged diameter excavation mechanism is moved up and down along the vertical drive shaft and positioned at the rib excavation position, and the vertical drive shaft is rotated to carry out the enlarged diameter excavation of the rib portion.
[0009]
According to a second aspect of the present invention, in the diameter-excavation method for a cast-in-place concrete pile with ribs according to the first aspect, the diameter-extended excavation mechanism includes an upper elevating part and a lower elevating part that are slightly smaller in diameter than the diameter of the shaft hole. , And an elevating type stabilizer having the same diameter as the shaft hole, and the upper elevating part and the lower elevating part can be engaged with or released from the vertical drive shaft so that rotational force and axial force can be transmitted. A large-diameter blade mechanism that expands in the radial direction and squeezes in the central direction at least in the upper elevating part. The upper elevating part and the lower elevating part are arranged parallel to the vertical drive shaft. Are connected to each other by an elevating jack that expands and contracts, and the elevating type stabilizer is configured to be provided in series at least below the lower elevating part.
[0010]
According to a third aspect of the present invention, there is provided a method for expanding a ribbed cast-in-place concrete pile according to the first aspect, wherein the excavated earth and sand generated by the expanded diameter excavation of the rib portion by the expanded diameter excavation mechanism is fixed and excavated by the shaft core. It is stored in a sediment collection bucket and discharged to the ground.
The ribbed cast-in-place concrete pile diameter expansion excavator according to the invention of claim 4 is an axial center fixed and excavated earth and sand collection bucket attached to the tip of a vertical drive shaft such as a kelly bar shaft of an earth drill, It consists of an enlarged diameter excavation mechanism of the rib part attached to the middle part of the Kelly bar shaft,
The diameter digging mechanism is composed of an upper elevating part slightly lower than the diameter of the shaft hole, a lower elevating part, and an elevating stabilizer having substantially the same diameter as the diameter of the shaft hole. A diameter-enlarging blade mechanism that has an attachment / detachment mechanism that can be engaged with or released from the vertical drive shaft so that rotational force and axial force can be transmitted, and that expands radially at least in the upper lifting part 2 to 4 are provided, and the upper elevating part and the lower elevating part are connected by an elevating jack extending and contracting in parallel with the vertical drive shaft, and the elevating stabilizer is at least below the lower elevating part. It is characterized by being provided in series.
[0011]
According to the fifth aspect of the present invention, the shaft core fixing and excavating earth and sand collection bucket of the ribbed cast-in-place concrete pile expansion drilling machine according to claim 4 opens upward with substantially the same diameter as the shaft hole. Each is characterized in that it has a container structure, has a downward projection at the center of the bottom surface, has a drain hole, and is connected to the kelly bar shaft in a configuration that does not transmit rotational force.
[0012]
Embodiments and Examples of the Invention
The diameter-extended excavator for the rib portion of the cast-in-place concrete pile with ribs according to the inventions as claimed in claims 4 and 5 is attached to the tip portion of the kelly bar shaft 1 of the earth drill as shown in FIG. The shaft fixing and excavating earth and sand collecting bucket 2 and a diameter expanding excavating mechanism 3 attached to an intermediate portion of the Kelly bar shaft 1 so as to be movable up and down. However, this embodiment only uses the kelly bar shaft 1 on the assumption that the cast-in-place concrete pile hole (shaft hole) 4 is excavated with an earth drill. is not. The vertical drive shaft that is supported with high vertical accuracy like the earth drill's kelly bar shaft and can transmit rotational force and penetrate into the ground is adopted in exactly the same way and implemented as a component of a large-diameter excavator. Can do.
[0013]
In the embodiment of FIG. 1, the earth drill bucket is removed from the kelly bar shaft 1 on the ground work floor as a setup change after the excavation of the shaft hole 4 for the pile is completed by the earth drill, and the kelly bar shaft 1 is removed. First, the shaft fixing and excavating earth and sand collecting bucket 2 is attached to the tip of the kelly bar shaft 1 through the central portion of the diameter expanding excavating mechanism 3.
[0014]
As described in detail in FIGS. 2 to 4, the above-described enlarged diameter excavation mechanism 3 is substantially the same as the diameter of the upper elevating part 3 </ b> A and the lower elevating part 3 </ b> B and the diameter of the shaft hole slightly smaller than the diameter of the shaft hole 4. It consists of a lifting / lowering stabilizer 3C having the same diameter. The upper elevating part 3A and the lower elevating part 3B are provided with an attachment / detachment mechanism part 30 (FIG. 3) described later that can be engaged with or released from the kelly bar shaft 1 so that rotational force and axial force can be transmitted. In the case of the illustrated example, only two upper diameter lifting mechanisms 31 that expand outward in the radial direction and narrow in the center direction are provided only in the upper elevating part 3A (FIG. 3). The upper elevating part 3 </ b> A and the lower elevating part 3 </ b> B are connected in series by an elevating jack 32 that extends and contracts in parallel with the kelly bar shaft 1. In the illustrated example, the elevating stabilizer 3C is connected to the lower side of the lower elevating part 3B by a connecting shaft 33 in a series of relationships.
[0015]
However, the lower elevating part 3B can also be implemented by providing an enlarged blade mechanism that expands outward in the radial direction and narrows toward the center. Further, the elevating type stabilizer 3C may be provided in a series of relations on the upper side of the upper elevating part 3A.
As shown in FIG. 5, the shaft core fixing and excavating earth and sand collection bucket 2 has a container structure that opens upward with substantially the same diameter as the shaft hole 4, and includes a downward projection 2a at the center of the bottom surface. Yes. In addition, a plurality of drain holes 2b are provided at the lower portion of the side wall so as to reduce mud resistance during lifting and to allow dewatering when the mud is pulled up. The diameter of the drain hole 2b is formed so as to prevent the stored excavated earth and sand from flowing out to the minimum and muddy water can be quickly removed (about φ100 mm). The shaft core fixing and excavating earth and sand collection bucket 2 is connected to the kelly bar shaft 1 by rotating bearings 2c and 2d configured to transmit a vertical force at least at two locations on the upper and lower sides but not to transmit a rotating force. Yes. The lower elevating part 3B and the elevating stabilizer 3C pass the excavated sediment so that the shaft core fixing and excavated sediment collection bucket 2 can accommodate all of the excavated sediment generated and dropped (sinked) by the expanded digging. It is a hollow structure that can be dropped (see FIG. 6).
[0016]
FIGS. 2 and 4 show an example of the structure of the detachable mechanism 30 that can be engaged with or released from the Kelly bar shaft 1 in the upper elevating part 3A and the lower elevating part 3B. Show. Four shaft fixing bits 30a that bite on the surface of the kelly bar shaft 1 are arranged in four directions at right angles around the kelly bar shaft 1 (however, the number and arrangement are not limited to this), and this shaft fixing bit 30a. Is driven from the rear by a hydraulic cylinder 30b for pushing out a bit. 4 is a spring for restoring the pits.
[0017]
Further, the diameter increasing blade mechanism 31 of the upper elevating part 3A has the base end of the diameter increasing excavating blade 31a rotated by the pins 35 to the upper and lower end plates 34 of the upper elevating part 3A as shown in FIG. Mounted and supported movably. The output shaft of the large-diameter blade pushing jack 36 is hinged to the back side of the large-diameter drilling blade 31a by a pin 37, and the base end side of the large-diameter blade pushing jack 36 is also the upper and lower ends of the upper elevating part 3A. The plate 34 is pivotally attached and supported by a pin 38. Accordingly, in accordance with the expansion and contraction operations of the diameter expansion blade push-out jack 36, the diameter expansion excavation blade 31a expands radially outward to enable the diameter expansion excavation of the rib portion, and conversely the radial center direction. The inside of the shaft hole 4 is squeezed (inner side), and the movement is accommodated in a form that does not hinder the lifting / lowering in the shaft hole 4 at all.
[0018]
The lifting / lowering jack 32 connecting the upper lifting / lowering part 3A and the lower lifting / lowering part 3B expands / contracts with a certain stroke, and the upper lifting / lowering part 3A and the lower lifting / lowering part 3B that take a reaction force against the kelly bar shaft 1 are operated by a so-called worm action. Move up and down.
As a measuring means for confirming the depth position of the diameter expansion excavation mechanism 3 (the diameter expansion excavation blade 31a), for example, one end of the scale is fixed to the diameter expansion excavation mechanism 3, and the other end side is pulled up on the ground work floor. A method for reading the depth can be implemented. Alternatively, a method of confirming the detection signal on the ground display by attaching a depth meter to the diameter expansion excavation mechanism 3 or controlling the stroke of the above-described lifting jack 32 on the ground and reading the number of expansions and contractions to confirm the depth. A method can also be implemented.
[0019]
Next, the operation of the above-described diameter-extended excavator and a method of performing diameter-excavation of the rib portion of the cast-in-place concrete pile with ribs using the same machine will be described.
After the excavation of the shaft hole 4 of the cast-in-place concrete pile is completed, the diameter-extended excavator attached to the kelly bar shaft 1 of the earth drill is inserted into the hole and lowered. At this time, the upper and lower elevating parts 3 </ b> A and 3 </ b> B are firmly fixed to the kelly bar shaft 1 by using the respective attachment / detachment mechanism parts 30. The core of the tip of the kelly bar shaft 1 is fixed and the excavated sediment collection bucket 2 is fixed to the bottom of the hole, and the downward projection 2a is sufficiently deeply inserted into the bottom of the hole to fix the bottom of the kelly bar shaft 1. I do. Then, after confirming the vertical accuracy of the kelly bar shaft 1, the enlarged diameter excavating mechanism 3 is moved up and down along the kelly bar shaft 1, and positioned at the excavation position of the rib portion 6 of the cast-in-place concrete pile. The diameter 6 of the rib portion 6 is excavated using the rotation of.
[0020]
Ascending / descending operation of the diameter expanding excavation mechanism 3 causes the detachable mechanism portions 30 of the upper elevating unit 3A and the lower elevating unit 3B to alternately engage or disengage the kelly bar shaft 1 and simultaneously extend and retract the lifting jack 32. To move up or down with a worm-like movement. When the diameter expansion excavation position is determined, the attaching / detaching mechanism 30 of the upper elevating part 3A is engaged with and fixed to the kelly bar shaft 1, and the rotation of the kelly bar shaft 1 is transmitted to the upper elevating part 3A. With the rotation of the kelly bar shaft 1, the diameter expanding excavation blade 31a of the diameter expansion blade mechanism 31 installed in the upper elevating / lowering section 3A is gradually expanded outward and the diameter of the rib section 6 is expanded.
[0021]
The above-described up-and-down excavation mechanism 3 is moved up and down, positioned, and expanded-diameter excavation is repeated to form a necessary number of enlarged-diameter portions (rib portions 6) at the necessary positions of the shaft hole 4.
Further, in the above-described method for expanding the diameter of the rib portion of the cast-in-place concrete pile with ribs, the excavated sediment generated by the expanded diameter excavation of the rib portion by the expanded diameter excavation mechanism 3 is allowed to settle, and the shaft core is fixed and excavated. It is received and stored in the earth and sand recovery bucket 2, and is lifted to the ground together with the kelly bar shaft 1 and discharged at the end of the excavation work (or a necessary stage in the middle of excavation).
[0022]
[Effects of the present invention]
According to the method for expanding the diameter of the rib portion of the cast-in-place concrete pile with rib and the diameter expanding excavator according to the present invention, the vertical drive shaft (Kelly) positioned with high vertical accuracy in the axis of the pile hole (shaft hole) The diameter-expanded excavation with the bar shaft as the support point (center) is performed, and a diameter-expanded shape concentric with the shaft hole and having a highly accurate rib width can be obtained.
[0023]
Axial core fixing and excavation earth and sand collection bucket located at the tip of the vertical drive shaft (Kelly bar shaft) firmly fixes the shaft core at the bottom of the vertical drive shaft, and also suppresses vertical movement during expanded digging, thus expanding digging Therefore, a predetermined accurate diameter-expanded shape can be realized.
The fixed core and excavated sediment collection bucket that settles at the bottom of the hole receives the excavated sediment generated during diameter expansion excavation and can efficiently transport it to the ground at the bottom of the final stage. The number of times of lifting and lowering the bucket can be reduced as much as possible, so that the risk of damaging the hole wall can be minimized.
[0024]
By adjusting the stroke of the lifting jack and fixing the positions of the upper and lower lifting parts, it is possible to accurately carry out the diameter-expanded excavation of the rib shape at the designed predetermined depth position at the designed predetermined interval.
Therefore, it contributes to the construction of a cast-in-place concrete pile with ribs in which the pulling resistance force or the supporting force is reliably increased as designed.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a construction diagram of a diameter-excavated excavator for a cast-in-place concrete pile with ribs.
FIG. 2 is a detailed view of a diameter expanding excavation mechanism.
3 is a cross-sectional view taken along the line 2-2 in FIG. 2;
4 is a cross-sectional view of a Y portion in FIG. 2. FIG.
FIG. 5 is a cross-sectional view of a bucket portion.
6 is a cross-sectional view taken along arrow XX in FIG.
[Explanation of symbols]
4 Pile hole (shaft hole)
1 Kelly bar shaft (vertical drive shaft)
2 Shaft fixing and excavation earth and sand collection bucket 3 Expanded diameter excavating mechanism 3A Upper lift unit 3B Lower lift unit 3C Lifting stabilizer 30 Detachable mechanism unit 31 Expanding blade mechanism 32 Lifting jack 33 Connecting shaft 2a Projection

Claims (5)

After completing the drilling of the shaft hole of the cast-in-place concrete pile, attach the shaft core fixing and excavation soil collection bucket to the tip of the vertical drive shaft like the Kelly bar shaft of the earth drill, and the middle part of the Kelly bar shaft Inserting a diameter expansion excavator equipped with a diameter expansion excavation mechanism, and fixing the shaft core fixing and excavating earth and sand collection bucket to the bottom of the shaft hole portion to fix the shaft core of the Kelly bar shaft, After that, a ribbed cast-in-place concrete is characterized in that the enlarged diameter excavation mechanism is moved up and down along the vertical drive shaft to be positioned at a rib excavation position, and the vertical drive shaft is rotated to carry out diameter expansion excavation of the rib portion. Pile expansion drilling method. The large-diameter excavation mechanism is composed of an upper lifting part and a lower lifting part that are slightly smaller than the diameter of the shaft hole, and a lifting type stabilizer that is substantially the same diameter as the diameter of the shaft hole. Enlarged blade that has a detachable mechanism that can be engaged with or released from the vertical drive shaft so that rotational force and axial force can be transmitted. A mechanism is provided, and the upper elevating unit and the lower elevating unit are connected to each other by an elevating jack that extends and contracts in parallel with the vertical drive shaft, and the elevating type stabilizer is at least below the lower elevating unit. The method for expanding the diameter of a cast-in-place concrete pile with ribs according to claim 1, characterized in that the structure is provided on the surface. 2. The cast-in-place with rib according to claim 1, wherein the excavated earth and sand generated by the diameter-expanded excavation of the rib portion by the diameter-expanded excavating mechanism is stored in a fixed shaft and excavated earth and sand collecting bucket and discharged to the ground. Method for expanding diameter of concrete piles. It consists of a shaft core fixing and excavating earth and sand collecting bucket attached to the tip of a vertical drive shaft such as a Kelly bar shaft of an earth drill, and a rib expanding digging mechanism attached to an intermediate part of the vertical drive shaft. ,
The diameter digging mechanism is composed of an upper elevating part slightly lower than the diameter of the shaft hole, a lower elevating part, and an elevating stabilizer having substantially the same diameter as the diameter of the shaft hole. A diameter-expanding blade provided with an attachment / detachment mechanism portion that can be engaged with or released from the vertical drive shaft so that rotational force and axial force can be transmitted, and that expands in the radial direction at least in the upper lifting portion 2 to 4 mechanisms are provided, and the upper elevating unit and the lower elevating unit are connected by an elevating jack that extends and contracts in parallel with the vertical drive shaft, and the elevating stabilizer is at least below the lower elevating unit An expanded drilling machine for ribbed cast-in-place concrete piles, characterized by being provided in series. The shaft core fixing and excavating earth and sand collection bucket has a container structure that opens upward with approximately the same diameter as the diameter of the shaft hole, has a downward projection at the center of the bottom, has a drain hole, and has a vertical drive shaft and 5. The diameter-excavated excavator for cast-in-place concrete piles with ribs according to claim 4, wherein the two are connected in a configuration that does not transmit rotational force.

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