JP2004324381A - Erection method with enlarged diameter part of precast pile, and enlarging excavating rod used for the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem of applying extremely large rotational load to an enlarging excavating rod by expanding enlarging excavating blades into the maximum expanding positions always at a stroke to carry out enlarging excavation. <P>SOLUTION: The outer peripheral surface of a rod having an excavating head at the lower end is provided with a plurality of enlarging excavating blades expansibly at spaces in the axial direction, and each enlarging excavating blade can be operated to expand in an optional expanding position. The enlarging excavating rod of such constitution is used and rotated to excavate a vertical hole in the ground, and cement milk is injected in the vertical hole. The enlarging excavating blades are expanded into the maximum expanding positions stepwise according to an erection length, an excavation diameter, the hardness of the ground, and the like to excavate a plurality of enlarged diameter annular holes, and a precast pile is pressed into the vertical hole to form a plurality of mortar enlarged diameter parts at the outer periphery of the precast pile. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method for forming a pre-formed pile used for a structure support pile or the like into a ground by forming a mortar enlarged portion on an outer periphery thereof and an enlarged excavation rod used for the method.
[0002]
[Prior art]
Conventionally, in the so-called pre-boring method of excavating a vertical hole, injecting cement milk into the vertical hole, and then press-fitting the existing concrete pile into the vertical hole, in order to improve the bearing capacity of the concrete pile, There is a construction method in which a pile is formed underground by forming a mortar enlarged portion on the outer periphery thereof.
[0003]
As an example, on the outer periphery of a rod having a drilling head at the lower end, a plurality of arms are protruded horizontally at intervals in the axial direction, and an enlarged drilling claw at the tip of each arm is closed and closed at the time of normal rotation of the rod. Using an enlarged drilling rod that is swingably supported on a horizontal plane so that it expands due to earth pressure during reverse rotation, first, while drilling the vertical hole by the forward rotation of the drilling rod, cement milk is introduced into the vertical hole. And then expand the expanding claw by reverse rotation of the drilling rod to excavate a plurality of enlarged annular holes, and then press-fit an existing concrete pile into the vertical hole, and thereby the outer periphery of the concrete pile. There is known a method for providing a plurality of mortar enlarged portions to a mortar.
[0004]
Further, a plurality of bearings are protruded from the same rod outer circumference as in the above example at an axial interval, and each of the bearings supports a rod-shaped enlarged drilling bit so as to be able to swing on a horizontal plane. A bracket having a hole that is movably inserted is rotatably supported by the rod, and the drill bit retracts when the rod rotates forward, and the bracket retracts due to earth pressure when the rod rotates backward to project the drill bit. A method of forming a plurality of mortar enlarged-diameter portions on the outer periphery of an existing pile using the enlarged excavation rod as described above is also performed.
[0005]
[Means for Solving the Problems]
However, in any of the conventional rods described above, a plurality of enlarged excavation claws or bits are projected at once at an enlarged and expanded position by earth pressure, and at the same time, project. If it is large, if the ground is hard, etc., an extremely large rotating load will be applied at the time of enlarged excavation, and if it can not turn, it will cause an accident of rod breakage. Since it protrudes, soil excavated during reverse rotation must be returned downward, and as a result, there is a disadvantage that the quality of cement milk at the lower end of the pile is reduced.
[0006]
[Problems to be solved by the invention]
The first invention of the present application improves the case where an extremely large rotating load is applied when the built-in length is long, the excavation diameter is large, the ground is hard, etc. by changing the method of expanding and contracting the enlarged excavation blade by earth pressure. That is the task.
[0007]
The second invention of the present application aims to obtain an enlarged excavation rod suitable for carrying out the first invention.
[0008]
As means for achieving the above object, the first invention of the present application is:
A plurality of enlarged digging blades are provided on the outer peripheral surface of a rod having a digging head at the lower end at intervals in the axial direction so as to be able to expand and contract, and each of the enlarged digging blades can be expanded to an arbitrary expanding position. Using an enlarged drilling rod,
Drilling a vertical hole in the ground by the rotation of the enlarged drilling rod and injecting cement milk into the vertical hole,
The above-described enlarged excavation blade is excavated to a plurality of enlarged-diameter annular holes by expanding stepwise to the maximum expansion position in accordance with the built length, excavation diameter, hardness of the ground, and the like,
Preformed piles were pressed into the vertical holes, and a plurality of mortar enlarged portions were formed on the outer periphery of the preformed piles.
We propose a built-in construction method of the existing pile with the enlarged diameter part.
[0009]
The second invention of the present application is
On the outer peripheral surface of a hollow rod having a drilling head at the lower end, spaced apart in the axial direction, a plurality of enlarged drilling blades are provided so as to be able to expand and contract,
A driving force transmitting member extending from the upper end of the rod to the plurality of enlarged excavation blades along the rod is disposed so as to be vertically movable,
The transmission member is connected to each of the enlarged excavation blades so that the transmission member can be expanded and contracted by the vertical movement of the transmission member. At the upper end of the transmission member, the expansion operation of each of the enlarged excavation blades is maximally expanded. Connected driving means for outputting a vertical driving force that can be operated stepwise to the position,
An extended drill rod is proposed.
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0010]
【Example】
For convenience, an embodiment of the second invention will be described first. In FIG. 1, a rotation drive unit (4) having a motor and a reduction gear is slidably mounted on guide rails (3) and (3) of a mast (2) vertically supported by a front end of a crawler (1). The upper end of the enlarged excavation rod (7) according to the present invention is connected to the output shaft (6) of the drive unit (4) by engaging and supporting it and suspending it vertically by a wire (5).
[0011]
The structure of the enlarged drilling rod (7) will be described below. Near the upper end of a hollow rod (8) having a drilling head (9) at the lower end, an expansion and contraction drive (A) for the expanding digging blade is equipped, on the outer surface of the rod (8) below the drive (A), A plurality of enlarged excavating blade devices (B) are provided at appropriate intervals in the axial direction, and transmission means for transmitting the vertical driving force of the enlarging / reducing drive (A) to each enlarged excavating blade device (B). (C) is extended from the driving device (A) along the rod (8) to the lowest excavating blade device (B)...
[0012]
First, the enlargement / reduction drive (A) is as follows. In FIG. 2, an upper flange (10), an intermediate flange (11) and a lower flange (12) are protruded from the outer peripheral surface of the rod (8) at appropriate intervals in the axial direction, and the flanges (10), ( Between 11), a sleeve (13) is fitted, the sleeve (13) is supported on a bearing (14), and the bearing (14) is attached to the guide rails (3), (3) of the mast. One end is fixed to the other end of the slidably engaged arm (15) (see FIG. 1) to prevent rotation, and a sleeve (16) is provided between the flanges (11) and (12). And the sleeve (16) is supported on a bearing (17), and the bearing (17) is connected to the guide rails (3) and (3) of the mast (2) at one end by an arm ( 18) (See FIG. 1) At this time, a space (d) required for driving is provided between the sleeve (16) and the flange (12), and a pair of hydraulic cylinders (19) are provided on the upper arm (15) as expansion / contraction driving means. ) And (19) are connected via brackets (21) and (21), and the ends of the rams (20) and (20) of both cylinders are mounted on the lower arm (18) with brackets (22) and (22). ).
[0013]
(23) is a lower annular plate which is rotatably and axially slidably fitted on the rod (8) below the lower flange (12), and is connected to the sleeve (16) by connecting rods (24). I have.
[0014]
In the above structure, if the hydraulic cylinders (19) and (19) are driven to expand and contract, the rams (20) and (20) move forward and backward through the sleeve (16), the bearing (17) and the arm (18). The annular plate (23) is moved up and down within the range using the distance (d) as a drive distance.
[0015]
Next, the highest-level enlarged excavation blade device (B) will be described. 3, 4 and 5, the upper and lower annular plates (25) and (26) are rotatably and axially slidably fitted on the rod (8), and both annular plates (25) and (26). Are connected at appropriate intervals by connecting bolts (27). At a position slightly lower between the annular plates (25) and (26), a curved substrate (28) (28) is bolted, and brackets (29) and (29) each having two rectangular plates are radially projected on each of the substrates (28) and (28). Future blocks (30) and (30) having guide round holes (31) and (31) for enlarged excavation blades at their tips are fixed.
[0016]
On the other hand, brackets (32), (32) project downward at positions corresponding to the brackets (29), (29) on the upper annular plate (25), and each bracket (32), (32) has One end of each of the links (33) and (33) is pivotally supported by pins (34) and (34), and the other end of the link is the two-piece brackets (29) and (29). The base end of the bar-shaped enlarged digging blade (35), (35) is attached to the extending end, the tip of the digging blade (35), (35) is connected to the guide hole (31), In the state inserted in (31), they are rotatably connected by pins (36) and (36).
[0017]
In this case, when the excavating blades (35) and (35) are retracted to a state where the tip is slightly protruded from the guide round holes (31) and (31), the links (33) and (33) are set at the lower end. Prefabricated pieces (37) and (37) are provided at the bases of the brackets (29) and (29) so as to be capable of taking a posture inclined outward by a required angle.
[0018]
In the above structure, when the upper annular plate (25) is pushed down, the links (33) and (33) further tilt the lower end outward, so that the excavating blades (35) and (35) are moved outward. To protrude the tip of the blade from the guide round holes (31), (31) to enable enlarged excavation.
[0019]
An auxiliary annular plate (38) is rotatably and axially slidably fitted on the rod (8) above the upper annular plate (25), and is connected to the annular plate (25) by connecting rods (39). Are linked.
[0020]
The other enlarged excavating blade devices (B) have substantially the same structure as the above example.
[0021]
Next, the transmission means (C) will be described. 2, the upper ends of four transmission rods (40) in this example are vertically fixed at equal intervals to the lower surface of the lower annular plate (23) of the expansion / contraction drive (A). 3 and vertically fixed to the upper surface of the auxiliary annular plate (38) of the uppermost enlarged excavating blade device (B) in FIG. 3, and then the uppermost excavating blade On the lower surface of the lower annular plate (26) of the device (B), the upper ends of three transmission rods (41) in this example are vertically fixed at equal intervals to each other, and the lower end of the rod (41) is fixed to the lower end. Vertically fixed to the upper annular plate of the second largest excavating blade device (B), and similarly, the lower annular plate and the upper annular plate of the excavating blade devices (B) and (B) vertically adjacent to each other in the same manner. Are connected by a transmission rod (41). (42) are connecting rings for connecting the four transmission rods (40) and the three transmission rods (41) and so on to each other.
[0022]
In the above structure, when the lower annular plate (23) is driven up and down by driving the hydraulic cylinders (19) and (19) of the expansion / contraction drive (A), the vertical driving force is transmitted to the transmission rod (40). Are transmitted to the links (33), (33),... Of the enlarged excavating blade devices (B) through the transmission rods (41),. To make it happen.
[0023]
An embodiment of the built-in method of the existing pile with the enlarged diameter portion using the enlarged excavation rod (7) will be described. In a state where the enlarged excavating blades (35) are closed and contracted, the rod (8) is rotated by starting the rotation drive unit (4), and the ground is excavated by the excavating head (9). The cement milk is discharged into the vertical hole (H) from the lower end of the rod (8) through the pipe (P) (see FIG. 4) vertically passed through the rod (8) while forming the vertical hole (H) as shown in FIG. I do. When the rod (8) rotates, the transmission rods (40),..., (41),... And the enlarged excavating blade device (B) below the lower annular plate (23) also rotate with the rod.
[0024]
After excavating the vertical hole (H) of a predetermined depth, the lower annular plate (23) is extended by the extension drive of the hydraulic cylinders (19) and (19) of the expansion / contraction drive (A) while continuing to rotate the rod (8). , And the driving force for the depression is transmitted to each upper annular plate (25) of each enlarged excavating blade device (B) through a transmission rod (40), and then to each of the enlarged cutting blade devices (B) through (41) ‥. The upper ends of the links (33) (33), ... in the device (B) ... are pushed down so that the enlarged excavation blades (35), (35), ... protrude from the guide round holes (31), (31), ..., and each excavation. Enlarged excavation is performed by the blades (35), (35),... And the entire enlarged excavated rod (7) is moved up and down a small distance, thereby forming an enlarged annular hole (R) as shown in FIG. I do.
[0025]
In this case, under conditions such as a large excavation diameter and a hard ground, etc., the enlarged excavation blades (35), (35),... Are slightly protruded by the inching operation of the hydraulic cylinders (19), (19). Excavates a slightly enlarged annular hole, and then slightly extrudes the excavating blades (35), (35), etc. by the same dimensional operation. In that state, further excavates a slightly enlarged annular hole. Is repeated stepwise to finally form the maximum expanded annular holes (R).
[0026]
Next, the enlarged drilling rod (7) is pulled out, and the concrete precast pile is inserted into the cement milk in the vertical hole (H). A concrete pile with an enlarged diameter part is formed by cement milk hardening.
[0027]
【The invention's effect】
According to the construction method of the first embodiment of the present invention, the enlarged pile is not always expanded to the maximum expansion position at a stroke to perform the extended excavation. When the diameter is large or the ground is hard, etc., the extremely large rotating load is applied to the enlarged drilling rod by gradually expanding the enlarged drilling blade gradually and finally to the maximum expanded position. This can be prevented, so that the intended enlarged annular hole can be reliably excavated.
[0028]
According to the enlarged excavation rod of the second invention of the present application, the method of the first invention can be effectively implemented, and each enlarged excavation blade is driven to expand / contract from the drive means at the upper end of the rod via the transmission member. Therefore, compared with the conventional method in which the enlarged drilling blade is expanded by reverse rotation of the rod, the mortar at the lower end of the formed pile can be maintained at a high quality.
[Brief description of the drawings]
FIG. 1A is a side view of an enlarged excavation rod according to a second invention of the present application.
(B) It is a side view at the time of enlarged excavation with the same rod.
FIG. 2 is an enlarged vertical sectional view of an enlargement / reduction drive unit.
FIG. 3 is an enlarged front view of an enlarged excavation blade device portion.
FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;
FIG. 5 is a sectional view taken along line VV of FIG. 4;
[Explanation of symbols]
8 Hollow rod 9 Drilling head 19 Hydraulic cylinder 35 Enlarged drilling blades 40, 41 Transmission rod

Claims (2)

A plurality of enlarged digging blades are provided on the outer peripheral surface of a rod having a digging head at the lower end at intervals in the axial direction so as to be able to expand and contract, and each of the enlarged digging blades can be expanded to an arbitrary expanding position. Using an enlarged drilling rod,
Drilling a vertical hole in the ground by the rotation of the enlarged drilling rod and injecting cement milk into the vertical hole,
The above-described enlarged excavation blade is excavated to a plurality of enlarged-diameter annular holes by expanding stepwise to the maximum expansion position in accordance with the built length, excavation diameter, hardness of the ground, and the like,
Preformed piles were pressed into the vertical holes, and a plurality of mortar enlarged portions were formed on the outer periphery of the preformed piles.
A built-in method with an enlarged part of a pre-built pile. On the outer peripheral surface of a hollow rod having a drilling head at the lower end, spaced apart in the axial direction, a plurality of enlarged drilling blades are provided so as to be able to expand and contract,
A driving force transmitting member extending from the upper end of the rod to the plurality of enlarged excavation blades along the rod is disposed so as to be vertically movable,
The transmission member is connected to each of the enlarged excavation blades so that the transmission member can be expanded and contracted by the vertical movement of the transmission member. At the upper end of the transmission member, the expansion operation of each of the enlarged excavation blades is maximally expanded. Connected driving means for outputting a vertical driving force that can be operated stepwise to the position,
Expanded drill rod.

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