JP4091939B2 - Pile head treatment method for cast-in-place concrete piles - Google Patents

Description

  The present invention relates to a pile head processing method for a cast-in-place concrete pile that can eliminate the work of removing defective concrete.

  In the formation of cast-in-place concrete piles, defective concrete containing slime or the like that reduces the strength of the piles is mixed in the upper end portion of the cast concrete cast into the pile hole. Therefore, concrete is placed in the pile head in advance by placing the concrete up to the upper part of the design pile top, and the pile head treatment is performed by removing this extra part. It was. The removal work of the extra portion has various difficulties in the suspending operation, so that the defective concrete is sucked and removed by the vacuum hose while the extra portion is uncured (for example, Patent Document 1). reference).

On the other hand, for example, Patent Document 2 is known as a method for performing pile head processing without overfilling. In Patent Document 2, the outside of the pile reinforcement of a cast-in-place concrete pile is surrounded by a cylindrical partition frame that includes a restraining member that suppresses concrete launching at the outer periphery of the lower end portion, and is surrounded to a predetermined depth from the designed pile top. , Pouring the cast concrete from the top of the partition frame to the area between the inner wall of the pile hole and the outer peripheral surface of the partition frame, removing the overflowed concrete as defective concrete, and placing the high quality on the top of the partition frame The concrete is placed in the pile hole until it is confirmed that the concrete appears. The removal of defective concrete was performed by a method such as vacuum suction as in Patent Document 1.
Japanese Patent Laid-Open No. 2003-064670 JP 2004-257065 A

  By the way, in any of the background arts, it is essential to remove defective concrete including slime from the pile hole regardless of whether there is a surplus or not. Specifically, in order to remove defective concrete, it is necessary to prepare various devices and perform a suction operation, which increases costs. In addition, due to the removal work of the defective concrete, the period until the completion of construction was prolonged. Also, during the suction work, the worker had to enter the pile hole to work. For this reason, the work environment is not good and improvement of work safety is desired, and the workable depth is about 4 to 5 m, which is unsuitable for construction deeper than that. On the ground with a high groundwater level, workers could not enter the pile hole, and construction on this kind of ground was difficult. In addition, a large amount of industrial waste was generated.

  The present invention has been developed in view of the above-described conventional problems, and an object thereof is to provide a method for treating a pile head of a cast-in-place concrete pile capable of eliminating the work of removing defective concrete.

The pile head processing method of a cast-in-place concrete pile according to the present invention includes excavating a pile hole by embedding a stand pipe in the ground, and then the outside of the pile rebar inserted into the pile hole from the design top of the pile to the stand. The steel pipe is surrounded to a position deeper than the pipe, and a cylindrical partition frame having an outer diameter equal to or smaller than the outer diameter of the steel pipe is placed on the upper end of the steel pipe, and through the inside of the cylindrical partition frame and the steel pipe, after Da設a higher concrete than the steel pipe upper end in the cylindrical partition frame, raises the cylindrical partition frame, concrete from the steel tube the upper end of the Da設the cylindrical partition frame, steel tube outer peripheral surface and said standpipe and flowed Yue on concrete was launched in the annular gap between, then lowers the weight to adjust the height of the Kuiten end to overflow on the residual concrete remaining without, on the steel tube The residual concrete from the steel tube upper end, characterized in that to flow overflow into the annular clearance.

  Further, the state in which the weight is lowered on the residual concrete is maintained for an appropriate period of time so that the flowability of the overflowed residual concrete is reduced and the returning action to the steel pipe is suppressed.

In the pile head processing method for cast-in-place concrete piles according to the present invention, it is possible to eliminate the removal work of defective concrete. More specifically, a cylindrical partition frame is placed on the upper end of the steel pipe, which is almost the design top of the pile, and serves as a placement space for surplus concrete mixed with defective concrete including slime. To adjust the pile top end position while allowing the surplus concrete to overflow into the annular gap and lowering the weight that adjusts the pile top end position to allow the residual concrete at the upper end of the steel pipe to overflow into the annular gap. Therefore, while filling high-quality concrete into the steel pipe that is the substantial part of the pile head, it is possible to remove the defective concrete from the cast-in-place concrete pile by flowing over the annular gap around the steel pipe.

EMBODIMENT OF THE INVENTION Below, suitable embodiment of the pile head processing method of the cast-in-place concrete pile concerning this invention is described in detail with reference to an accompanying drawing. As shown in FIG. 1 and FIG. 2, the pile head processing method for a cast-in-place concrete pile according to the present embodiment basically digs the pile hole 1 by embedding the stand pipe 7 in the ground GL, and then the pile hole The outside of the pile rebar 2 inserted into 1 is surrounded by a steel pipe 3 from the designed pile top end L to a position deeper than the stand pipe 7 , and the tubular partition frame 4 having an outer diameter of the steel pipe 3 or less is connected to the steel pipe 3. After placing concrete C higher in the cylindrical partition frame 4 than the upper end 3a of the steel pipe 3 through the inside of the cylindrical partition frame 4 and the steel pipe 3, the cylindrical partition Concrete that has been raised in the cylindrical partition frame 4 by raising the frame 4 from the upper end 3a of the steel pipe 3 into the annular gap δ between the outer peripheral surface 3b of the steel pipe 3 and the stand pipe 7 flowed Yue on C, then the residue without overflow And it lowers the weight 5 to adjust the height of the Kuitentan L on the residual concrete Ca, so as to flow overflow into the annular gap δ residual concrete Ca on steel pipe 3 from the upper end 3a of the steel pipe 3. In addition, the state in which the weight 5 is lowered on the residual concrete Ca is maintained for an appropriate time during which the flowability of the overflowed residual concrete Ca is reduced and the return action on the steel pipe 3 is suppressed.

In this embodiment, the case of the construction of the in-situ concrete pile 6 using the steel pipe 3 will be described as an example. The cast-in-place concrete pile 6 itself is constructed according to a conventionally well-known procedure, and the present invention has a feature in pile head processing. When constructing the cast-in-place concrete pile 6, as shown in FIG. 1, first, a stand pipe 7 that is a part of the pile hole 1 is embedded in the ground GL, and excavation, bottom expansion, and primary hole bottom of the pile hole 1 are performed. Process. The stand pipe 7 is embedded in consideration of its properties such as the ground GL being soft.

  Next, the reinforcing bar 2 a to be the pile reinforcing bar 2 is inserted into the pile hole 1. The pile reinforcement 2 is driven over almost the entire length of the pile hole 1 by connecting the reinforcement rods 2a having appropriate lengths, and the reinforcement rods 2a are sequentially connected according to the progress of the insertion work. The steel pipe 3 is joined to the outside of the reinforcing bar 2a at the top of the pile rebar 2 so as to surround the pile rebar 2. The upper end of the pile reinforcement 2 may be covered with the steel pipe 3 or may be protruded outward from the steel pipe 3. Then, the steel pipe 3 is inserted into the pile hole 1 together with the pile rebar 2. Next, the tremy tube 8 is inserted into the pile hole 1 and further subjected to secondary hole bottom treatment, and then the concrete C is cast to form the cast-in-place concrete pile 6.

  In particular, in this embodiment, as shown in FIG. 2, when the steel pipe 3 is joined to the pile rebar 2, the pile rebar 2 is extended from the design top edge L (see FIG. 2 (e)) to a suitable depth. The length and the joining position are set so as to surround. That is, the upper end 3a of the steel pipe 3 is an approximate design pile top end L. Further, as shown in FIG. 2 (a), the steel pipe 3 is an outer surface in which an annular gap δ is formed between the outer peripheral surface 3b of the steel pipe 3 and the inner wall surface 1a of the pile hole 1 or the inner peripheral surface of the stand pipe 7. It is formed with a diameter. The flat cross-sectional shape of the steel pipe 3 may be any shape such as a circle or a polygon. Moreover, in this embodiment, in order to increase the amount of reinforcing bars of the pile head, the outer peripheral surface 3b of the steel pipe 3 protrudes upward from the upper end 3a of the steel pipe 3 with an appropriate interval in the circumferential direction. Thus, a plurality of anchor muscles 9 are joined. The anchor muscle 9 may not be provided. Although not shown, the pile rebar 2 including the steel pipe 3 is provisionally received on the stand pipe 7 and installed in the pile hole 1.

  After the pile rebar 2 including the steel pipe 3 is inserted into the pile hole 1, the cylindrical partition frame 4 is placed on the upper end 3 a of the steel pipe 3 before placing the concrete C. The tubular partition frame 4 is arranged so that the upper end 4a of the tubular partition frame 4 is positioned above the steel pipe 3 in order to secure a space for placing surplus concrete on the upper end 3a of the steel pipe 3 positioned substantially at the pile top end L. It is arranged. The outer diameter of the cylindrical partition frame 4 is formed to be equal to or smaller than the outer diameter of the steel pipe 3 so that the cast concrete C does not leak from between the steel pipe 3 and the cast concrete C. The form of the flat sectional shape of the cylindrical partition frame 4 is not particularly limited, such as a circle or a polygon.

  The tubular partition frame 4 is installed on the steel pipe 3 with the suspension being guided using the anchor bars 9, and temporarily placed on the stand pipe 7. In the example of illustration, it sets so that the upper end of the pile reinforcement 2 may protrude from the upper end 4a of the cylindrical partition frame 4. FIG. You may install the cylindrical partition frame 4 so that the pile reinforcement 2 upper end may be concealed inside. About the installation method of the cylindrical partition frame 4, the lower end of the said cylindrical partition frame 4 is made to project from the radial direction outward from this, a metal object is provided, this metal object is hooked on the upper end 3a of the steel pipe 3, and the steel pipe 3 You may make it mount on top.

  Thus, after setting the cylindrical partition frame 4 so that it may be located above the steel pipe 3 in the pile hole 1, as shown in FIG.2 (b), the cylindrical partition frame 4 and the steel pipe 3 of FIG. Through the inside, the tremy tube 8 is inserted into the pile hole 1 and concrete C is placed. The concrete C is driven up to an annular gap δ between the steel pipe 3 and the outer peripheral surface 3b of the steel pipe 3 and the inner wall surface 1a of the pile hole 1 and the stand pipe 7, and is also driven into the cylindrical partition frame 4. In particular, in the cylindrical partition frame 4, surplus concrete Cb mixed with relatively light defective concrete containing slime or the like is launched.

  As shown in FIG. 2 (c), the tubular partition frame 4 is detachably attached with a wire 10 to be engaged with a lifting machine in order to lift and remove it from the steel pipe 3. ing. When the cylindrical partition frame 4 is raised through the wire 10, the surplus concrete Cb having fluidity in the cylindrical partition frame 4 overflows from the upper end 3 a of the steel pipe 3 to the annular gap δ by its own weight. The overflowed concrete flows into the concrete C in the annular gap δ that has already been launched. Moreover, a part of the surplus concrete Cb remains on the upper end 3 a of the steel pipe 3. By using the remaining concrete Ca, the pile top end L is adjusted to the design dimension as described later.

  Next, as shown in FIG. 2 (d), the weight 5 suspended from the lifting machine via the wire 11 is suspended in the pile hole 1 to the designed pile top end L position. Any weight 5 may be used, but in the present embodiment, a steel pipe filled with concrete is used. The weight 5 is lowered in a state suspended on the concrete Ca remaining on the upper end 3a of the steel pipe 3 without overflowing, whereby the residual concrete Ca is pushed by the weight 5 and overflows from the upper end 3a of the steel pipe 3. Thus, the final adjustment of the pile top end L position is performed. In this operation, for example, a ruler 12 is passed over the stand pipe 7, and the height of the weight 5 is added to the dimension measured by the measuring tape 13 suspended from the position of the ruler 12 to the upper end of the weight 5. Since the dimensions from the upper end of the pipe 7 to the lower end of the weight 5 are known, the pipe 5 is lowered so that the lower end of the weight 5 is positioned at the pile top end L position. Thereby, the residual concrete Ca which stays above the pile top end L position on the upper end 3a of the steel pipe 3 can be caused to overflow into the annular gap δ so as to ensure the pile top end L position.

  Thereafter, the state in which the weight 5 is lowered on the residual concrete Ca is maintained for an appropriate time during which the fluidity of the overflowing residual concrete Ca is reduced and the returning action to the steel pipe 3 is suppressed. As a result, it is possible to prevent the residual concrete Ca that has once overflowed from the steel pipe 3 from returning to the steel pipe 3 and changing the pile top end L position, thereby improving the position adjustment accuracy of the pile top end L position by the weight 5. Can be made. The appropriate time is about 20 to 30 minutes.

  Next, as shown in FIG. 2 (e), the weight 5 is pulled up from the inside of the pile hole 1, and after that, using the measuring tape 13 again, it is measured whether or not the pile top end L position is within the allowable dimension. Then, the stand pipe 7 is pulled up. Thereby, the pile head process at the time of creation of the on-site placement concrete pile 6 can be completed.

  In the pile head processing method for an on-site cast concrete pile according to the present embodiment described above, the surplus in which defective concrete including slime is mixed with the upper end 3a of the steel pipe 3 which is almost the designed pile top L. Place the cylindrical partition frame 4 that will be the space for placing concrete Cb, then raise the cylindrical partition frame 4 to overflow the surplus concrete Cb into the annular gap δ, and adjust the pile top end L position Since the weight 5 to be lowered is lowered and the residual concrete Ca at the upper end 3a of the steel pipe 3 is allowed to flow into the annular gap δ, the position of the pile top end L is adjusted. While filling the steel pipe 3 with high-quality concrete C, the defective concrete can be removed from the cast-in-place concrete pile 6 by flowing over the annular gap δ around the steel pipe 3 Defective concrete it is possible to eliminate the task of removing from Kuiana within 1 as.

  As a result, it is not necessary to prepare various devices or perform a suction operation in order to remove defective concrete, and cost reduction can be achieved. Moreover, since the removal work of the said defective concrete can be abolished, the period until construction completion can be shortened. In addition, it is not necessary for the worker to enter the pile hole 1 to work out the defective concrete, and the work environment and work safety can be improved. Furthermore, since it is not necessary for an operator to enter the pile hole 1, it is possible to perform construction at a deeper depth than in the past, and it is possible to construct even on the ground having a high groundwater level. Furthermore, since the removal work of defective concrete is unnecessary, generation | occurrence | production of the industrial waste accompanying this can be eliminated. Furthermore, the design pile top end L position can be set by the weight 5 capable of position measurement, and the pile head processing can be performed with high accuracy. Moreover, since the concrete in the cylindrical partition frame 4 becomes the surplus concrete Cb, the surplus concrete Cb can be managed appropriately.

  Further, the state in which the weight 5 is lowered on the residual concrete Ca is maintained for an appropriate period of time so that the flowability of the overflowed residual concrete Ca is reduced and the returning action onto the steel pipe 3 is suppressed. Only by leaving it for an appropriate period of time, it is possible to appropriately prevent the residual concrete Ca that has once overflowed from the steel pipe 3 from returning to the steel pipe 3 and changing the pile top end L position, and the weight 5 is suspended. Thus, the pile top end L position can be adjusted appropriately and accurately, and the necessity of the lifting work can be eliminated from this aspect.

It is a figure explaining the creation procedure of the cast-in-place concrete pile to which the pile head processing method of the cast-in-place concrete pile concerning this invention is applied. It is explanatory drawing explaining suitable one Embodiment of the pile head processing method of the in-situ concrete pile concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pile hole 2 Pile rebar 3 Steel pipe 4 Cylindrical partition frame 5 Weight C Concrete Ca Residual concrete Cb Extra pile L Designed pile top

Claims (2)

Drill a pile hole by embedding a stand pipe in the ground,
Next, the outside of the pile rebar inserted into the pile hole is surrounded by a steel pipe from the designed pile top to a position deeper than the stand pipe , and a cylindrical partition frame having an outer diameter equal to or less than the steel pipe is attached to the steel pipe. Put it on the top,
Through the inside of the cylindrical partition frame and the steel tube, after Da設a higher concrete than the steel pipe upper end to said tubular partition frame,
By raising the cylindrical partition frame, the concrete placed in the cylindrical partition frame is transferred from the upper end of the steel pipe onto the concrete that is launched into the annular gap between the outer peripheral surface of the steel pipe and the stand pipe. Let it flow,
Next, a cast-in-place is characterized in that a weight for adjusting the height of the top of the pile is lowered on the residual concrete remaining without overflowing, and the residual concrete on the steel pipe is allowed to overflow from the upper end of the steel pipe to the annular gap. Pile head treatment method for concrete piles.   The state in which the weight is lowered on the residual concrete is maintained for an appropriate period of time so that the flowability of the overflowed residual concrete is reduced and the return action to the steel pipe is suppressed. Pile head processing method for cast-in-place concrete piles.

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