JP2004324352A - Weight for rapid load test of pile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a weight for a rapid load test of a pile having excellent safety and repeatability with no waste in drop height in spite of weight structure divided in a plurality of parts. <P>SOLUTION: This weight 1 dropped onto a pile head to carry out the rapid load test of the pile comprises multiple rings, wherein the rings 2, 2 adjacent to one another inside and outside are connected in an axially movable manner, and the connecting means is provided with an engaging part 3 formed at the inner periphery of each ring excluding the ring at the innermost periphery, and a connecting cylinder 4 disposed between the inner and outer rings 2, 2 and formed with engaging parts 5, 6 at the outer periphery of the lower end and the inner periphery of the upper end. The lower end engaging part 5 and the upper end engaging part 6 of the connecting cylinder 4 can be engaged with the engaging part 3 of the outer ring 2 and the upper end face of the inner ring 2 respectively. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a weight for rapid loading test of piles, and more particularly to a weight structure which is a dynamic loading test but can obtain a result close to a static loading test by increasing a loading time.
[0002]
[Prior art]
Pile loading tests are classified into static loading tests and dynamic loading tests. In the former static loading test, a loading frame such as a loading device or a reaction force device becomes large-scale, and not only long time is required for preparation and execution of the test, but also large costs are required for assembly and disassembly. For these reasons, a dynamic loading test has recently attracted attention.
[0003]
The dynamic loading test is classified into a rapid loading test and an impact loading test. Among them, the former rapid loading test has a longer loading time than the latter impact loading test. (Approximately 0.1 seconds), a result close to that of a static loading test is obtained, and no complicated analysis by wave theory is required. There are several methods for performing a rapid loading test, and one of them is a soft cushion weight drop method. In this method, a cushion material such as styrofoam is installed on a pile head, and a weight is dropped toward the cushion material.
[0004]
In the rapid loading test by the soft cushion weight drop method, the present applicant has previously proposed a method in which the loading time is lengthened and can be made closer to the result of the static loading test (see Patent Document 1). This proposed technique is a method in which a plurality of divided hammers are used as hammers (weights) to be dropped on a pile head, and these divided hammers are sequentially dropped on a pile head at regular time intervals.
[0005]
However, although the concept of splitting the hammer and dropping it is novel and extremely excellent, the proposed technique has the following disadvantages in actual implementation.
[0006]
In the embodiment shown by the proposed technology, the hammer is divided into a plurality of flat plates, and the divided hammers are connected by a wire rope. In such a division form and a connection method, when each divided hammer is dropped, there is a possibility that the wire rope is caught between the divided hammers. As a result, the wire rope is damaged and causes breakage, which is dangerous. Further, when the wire rope is sandwiched between the divided hammers, the same impact cannot be generated every time the divided hammers collide.
[0007]
The technique shown in the embodiment is a dropping method in which a divided hammer that falls after and falls on a divided hammer that has fallen in advance collides. That is, since the divided hammers that have sequentially fallen are stacked in the vertical direction, the height of the fall is wasted. Further, since the divided hammers collide with each other, the hammers are easily deformed. Further, since the hammer is divided into a flat plate shape, a loud sound is generated at the time of collision.
[0008]
[Patent Document 1]
JP 10-153504 A
[Problems to be solved by the invention]
The present invention has been made based on the technical background as described above, and achieves the following objects.
An object of the present invention is to provide a weight for a rapid loading test of a pile, which has a weight structure divided into a plurality of parts, has no loss in drop height, and is excellent in safety, reproducibility and the like.
[0010]
[Means for Solving the Problems]
The present invention employs the following means to achieve the above object.
That is, the present invention is a weight for performing a rapid loading test of a pile by dropping the pile onto a pile head,
The weight comprises a multiple ring, and rings adjacent to each other inside and outside are connected movably in the axial direction.
[0011]
More specifically, the means for connecting the inner and outer rings is disposed between an engagement portion formed on the inner periphery of each ring except the innermost ring and the inner and outer rings, and has a lower end outer periphery and an upper end inside. A connection cylinder having an engagement portion formed around the periphery thereof, wherein the lower end engagement portion and the upper end engagement portion of the connection tube can be engaged with the engagement portion of the outer ring and the upper end surface of the inner ring, respectively. ing.
[0012]
The means for connecting the inner and outer rings includes an upper end engaging portion formed at the upper end inner periphery of each ring except the innermost ring, and a lower end formed at the lower end outer periphery of each ring except the outermost ring. And an engaging portion, wherein the upper end engaging portion of the outer ring can be engaged with the lower end engaging portion of the inner ring.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view showing an embodiment of the present invention, and FIG. 2 is a plan view. The weight 1 is composed of multiple rings. Each of the rings 2 constituting the multiplex ring is connected to each other inside and outside so as to be movable in the axial direction.
[0014]
In order to connect the inner and outer adjacent rings 2, an annular engaging portion 3 is formed on the inner periphery of each ring 2 except for the innermost ring 2, and a connecting cylinder 4 is provided between the inner and outer rings 2. Are located. Annular engaging portions 5 and 6 are formed on the outer periphery of the lower end and the inner periphery of the upper end of the connecting cylinder 4, respectively. The lower end engaging portion 5 of the connecting cylinder 4 can engage with the engaging portion 3 of the outer ring 2, and the upper end engaging portion 6 can engage with the upper end surface of the inner ring 2.
[0015]
FIG. 1 shows a state in which the innermost ring 2 is lifted. In this suspended state, the lower end engaging portion 5 of the connecting cylinder 4 engages with the engaging portion 3 of the outer ring 2, and the upper end engaging portion 6 engages with the upper end surface of the inner ring 2. A height difference is generated so that the height position is sequentially increased from the outermost ring 2 to the innermost ring 2.
[0016]
FIG. 3 is a diagram showing an example of a rapid loading test method using the weight composed of the multiple rings. A pedestal 8 is installed on the head of the pile 15 to be tested via a cushion material 7 made of styrene foam or the like. The pedestal 8 has a guide rod 9 in the center, and the innermost ring 2 is passed through the guide rod 9. The innermost ring 2 passed through the guide rod 9 is lifted to a predetermined height by a crane (not shown) via a rope 10 or the like. Accordingly, the entire weight 1 is lifted.
[0017]
When the weight 1 is dropped, a height difference occurs between the rings 2 in the suspended state as described above, so that the pile 1 collides with the pile head sequentially from the outermost ring 2 to the innermost ring 2. I do. As described above, since the plurality of rings 2 constituting the weight 1 collide with the pile head with a time lag, the loading time is prolonged, and a result similar to a static loading test is obtained.
[0018]
According to the above-described weight structure, each ring 2 is connected not through the wire rope but through the connecting cylinder 4, so that the wire rope does not get caught between the rings when it falls. Therefore, there is no risk of damage or breakage of the wire rope, so that it is safe. Further, since the wire rope is not pinched, the same impact can be generated every time. In addition, since the weight 1 has a multi-ring structure, there is no waste in the drop height, and the height of the implementation place is not easily limited. In addition, since the rings do not collide with each other, no deformation occurs, and furthermore, since the ring collides with the pile head at the axial end face, the sound at the time of collision does not increase.
[0019]
The time difference between the collision of each ring with the pile head, that is, the overall loading time, can be adjusted by changing the length of the connecting cylinder 4. FIG. 4 shows another embodiment in which the length of the connecting tube 4 is increased and the loading time is increased.
[0020]
It is also possible to adopt a structure in which the inner and outer rings 2, 2 are directly connected without using the connecting cylinder 4. FIG. 5 is a vertical sectional view showing the embodiment. In this embodiment, an annular engaging portion 11 is formed on the inner periphery of the upper end of each ring 2 except for the innermost ring 2, and an annular engaging portion 11 is formed on the outer periphery of the lower end of each ring 2 except for the outermost ring 2. A part 12 is formed. The upper end engaging portion 11 of the outer ring 2 can be engaged with the lower end engaging portion 12 of the inner ring 2. According to this embodiment, the same effects as those of the above embodiment can be obtained.
[0021]
As shown in FIG. 6, the upper end engaging portion 11 and the lower end engaging portion 12 may be separate from the main body 2a of the ring 2, and may be detachably attached by attaching means such as screws. By making the mounting position in the height direction relative to the ring main body 2a variable, it is possible to change the time difference between collisions of the rings with the pile head, that is, the overall loading time.
[0022]
The above embodiments are merely examples, and the present invention can take various aspects. For example, in the above embodiment, the intervals (height differences) between the inner and outer adjacent rings are substantially equal, but the intervals between the rings may be unequal. The ring is not limited to a circular ring, but may be a polygonal square ring.
[0023]
【The invention's effect】
As described above, according to the present invention, it is possible to carry out a load test which is not divided into a weight structure but has a high drop height and is excellent in safety and reproducibility.
[Brief description of the drawings]
FIG. 1 is a vertical sectional view showing an embodiment of the present invention.
FIG. 2 is a plan view of the same embodiment.
FIG. 3 is a diagram showing an example of implementation of a rapid loading test.
FIG. 4 is a vertical sectional view showing another embodiment.
FIG. 5 is a vertical sectional view showing still another embodiment.
FIG. 6 is a diagram showing a modification of the embodiment shown in FIG. 5;
[Explanation of symbols]
1: weight 2: ring 3: engaging portion 4: connecting cylinder 5: lower end engaging portion 6: upper end engaging portion 7: cushion material 8: pedestal 9: guide rod 10: wire rope 11: upper end engaging portion 12 : Lower end engaging part

Claims (3)

A weight for carrying out a rapid loading test of a pile by dropping it to a pile head,
The weight for a rapid load test of a pile, wherein the weight is composed of multiple rings, and rings adjacent to each other inside and outside are movably connected in the axial direction. Means for connecting the inner and outer rings, an engaging portion formed on the inner periphery of each ring except the innermost ring,
A connection cylinder disposed between the inner and outer rings, and a coupling cylinder formed with an engagement portion on the lower outer periphery and the upper inner periphery,
The pile quick loading according to claim 1, wherein a lower end engaging portion and an upper end engaging portion of the connecting cylinder can be engaged with the engaging portion of the outer ring and an upper end surface of the inner ring, respectively. Test weight. The means for connecting the inner and outer rings includes an upper end engaging portion formed at the upper end inner periphery of each ring except the innermost ring, and a lower end formed at the lower end outer periphery of each ring except the outermost ring. And an engaging portion,
The weight according to claim 1, wherein an upper end engaging portion of the outer ring is engageable with a lower end engaging portion of the inner ring.

Images