JPH10147934A - Pile head displacement measuring method at driving pile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pile head displacement measuring method at driving a pile which can accurately measure without using a special telescope lens and the like, in a system of photographing by a camera. SOLUTION: When a pile is driven by a percussion type pile driver, a target tape 2A is stuck on the side of the pile 1A to be driven as a measuring mark, and a target tape 2B is stuck on the side of a pile 1B adjacent to it and already driven as a reference mark. These two target tapes 2A, 2B are photographed by a camera 5 in the nearly horizontal direction so as to catch both the target tapes 2A, 2B in the same collimation territory 6, and by measuring displacement in the vertical direction X, (X+Y) of the respective target tapes 2A, 2B at a stationary state and at driving, a rebound quantity and penetrating quantity due to driving are calculated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring a pile head displacement at the time of driving a pile, which is preferably applied to driving a pile using a hitting type pile driving machine such as a diesel pile hammer or a hydraulic pile hammer.

[0002]

2. Description of the Related Art When a pile is driven into the ground by a percussion-type pile driver as described above, it is necessary to measure a rebound amount and a penetration amount at the time of driving in order to estimate a supporting force and the like. Conventionally, the measurement mainly relied on manual recording paper entry. Other than that, a method of photographing the pile during casting with a camera, a method of attaching an accelerometer to the pile during casting, and the like have been considered.

[0003]

By the way, the conventional manual recording method of recording paper is dangerous because the operation is performed right beside the pile being driven. Also, the camera shooting method is that the camera shakes together with the vibration at the time of pile driving,
There was a problem that accuracy was poor. Further, if the measurement distance is increased to prevent shaking, an extreme telephoto lens is required, which may increase the cost. In addition, the method of attaching the accelerometer has a problem in that since the measuring instrument is attached to the pile, the impact resistance of the instrument and the method of attaching the instrument need to be devised, resulting in an increase in cost.

[0004] In view of the above circumstances, the present invention provides a method of photographing with a camera without using a special telephoto lens or the like.
It is an object of the present invention to provide a pile head displacement measurement method at the time of pile driving that can be measured with high accuracy.

[0005]

According to a first aspect of the present invention, there is provided a measuring method, wherein when a pile is driven into a ground by a hammering type pile driving machine, a mark for measurement is provided on a side surface of a pile to be driven.
A reference mark is provided on the side of the driven pile close to it, these two marks are photographed by a camera from a substantially horizontal direction, and both marks are captured in the same collimation area. It is characterized in that the amount of rebound due to driving and the amount of penetration are determined by measuring the vertical displacement.

A method according to a second aspect of the present invention is characterized in that a tape that can be distinguished from the surface of the pile is attached as the measurement mark and the reference mark.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1A is a plan view showing a situation at the time of stakeout, FIG. 1B is a side view of the same, and FIG. 1C is a view showing the contents of a screen shot by a camera.

When this measuring method is carried out, when the pile 1 is driven into the ground T with a percussion type pile driving machine, the target tape 2A for measurement is attached to the outer peripheral side surface of the pile 1A to be driven as a mark for measurement. The reference target tape 2B is pasted as a reference mark on the outer peripheral side of the head of the driven pile 1B that has been pasted. As these target tapes 2A and 2B, a reflective tape, a luminous tape, or the like that can be identified from the pile surface is used.

When the target tapes 2A and 2B are pasted in the same direction, a camera (for example, a CCD camera) 5 capable of photographing a moving image is installed in a horizontal direction perpendicular to the surface on which the tapes 2A and 2B are pasted. Camera 5
The camera 5 is connected to a processing device (personal computer) 7 for analyzing an image captured by the camera 5. However, this camera 5 is capable of capturing both target tapes 2A and 2B within the same collimation area 6 (for example, 20 to 50).
m).

When the above preparations are completed, stakeout is carried out by a hitting type stakeout machine, and the two target tapes 2A,
2B is captured in the same collimation area 6, and the vertical displacement of each of the target tapes 2A and 2B at the time of stopping and driving is recorded as an image. Then, by processing the record by the processing device 7, the amount of rebound and the amount of penetration caused by the driving are calculated and output.

The contents of the processing will be described with reference to the screen shown in FIG. Note that the target tape 2A shown by hatching
-1, 2B-1 are the positions at the time of rest, and the target tapes 2A-2, 2B-2 shown in white are the positions at the time of hitting (at the time of driving).

The vertical displacement X when the target tape 2B of the driven pile 1B is stationary and when hit is equivalent to the swing displacement of the camera 5 due to ground vibration, that is, the rebound amount.
Therefore, the rebound amount can be determined by determining the value of X. Also, the target tape 2 of the pile 1A being driven
The vertical displacement (X + Y) when A is stationary and when hitting is the sum of the swinging displacement of the camera 5 due to ground vibration and the displacement due to hitting. Accordingly, the amount of penetration of the pile 1A can be determined by obtaining a value Y obtained by subtracting X from the displacement (X + Y) of the target tape 2A for measurement.

As described above, the target tape 2 for measurement
By using the reference target tape 2B along with A, it is possible to accurately measure the rebound amount and the penetration amount at the time of pile driving, respectively. Moreover, since the rebound amount and the penetration amount are calculated while using the shaking of the camera 5, the camera 5 can be installed and measured at a relatively short distance from the stakeout point. Therefore, it is not necessary to use a high-magnification telephoto lens or the like, and an increase in cost can be suppressed. In addition, since the measurement can be performed close to the lens and the magnification of the lens can be suppressed to a small value, the enlargement ratio of the screen shake is reduced, and the measurement accuracy is improved accordingly. In addition, since it is possible to measure from a distant position only by sticking the target tapes 2A and 2B, there is no need to take special measures for mounting the instrument, and no person enters under the pile driver being hit. Work safely.

The two target tapes 2A, 2B
The error due to the distance in the depth direction can be kept within the range that can be processed by calibration.
There is no need to use expensive cameras. Moreover, since the pile 1B which has been driven is driven into the support layer, there is almost no influence of vibration due to the driven pile. It is desirable that the installation direction of the camera 5 be perpendicular to the surface to which the target tapes 2A and 2B are attached, but there is no problem even if the camera 5 is slightly inclined. In addition, the mark may be provided by a method of marking with paint or the like other than the target tape.

[0015]

As described above, according to the first aspect of the present invention, at the time of pile driving, marks are provided on the side of the pile to be driven and the side of the driven pile, respectively. Since the camera is photographed so as to be within the same collimation area, and the displacement of the pile head is measured by the vertical displacement of both marks, the rebound amount and the penetration amount due to the pile driving can be measured with high accuracy. Moreover, since the amount of rebound and the amount of penetration are calculated while using the camera shake, the camera can be installed and measured at a relatively short distance from the stakeout point, so that a high-magnification telephoto lens or the like can be used. There is no need to use it, and a rise in cost can be suppressed.
In addition, because it is possible to measure from a distant position just by marking the pile, special measures are required for mounting the instrument, and people do not enter under the pile driving machine being hit, which increases costs. Measurement work can be performed safely without the need.

According to the second aspect of the present invention, if tapes are attached as measurement and reference marks,
It can be easily pasted or peeled off,
Work becomes easier.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a measuring method according to an embodiment of the present invention;
(A) is a plan view showing a situation in which the measurement method is being implemented,
(B) is a side view of the same, and (c) is a view of a camera screen.

[Explanation of symbols]

 1A Pile to be driven 1B Pile already driven 2A Target tape (mark for measurement) 2B Target tape (mark for reference) 5 Camera 6 Collimation area

Claims (2)

[Claims] When a pile is driven into a ground by a percussion type pile driving machine, a mark for measurement is provided on a side surface of a pile to be driven, and a reference mark is provided on a side surface of a driven pile close to the pile. By capturing these two landmarks with a camera from a substantially horizontal direction and capturing both landmarks in the same collimation area, measuring the vertical displacement of each landmark at rest and during driving, the amount of rebound due to driving and the amount of penetration A pile head displacement measurement method at the time of pile driving characterized by calculating the amount. 2. As the measurement mark and the reference mark,
The pile head displacement measuring method at the time of pile driving according to claim 1, wherein a tape that can be identified from the surface of the pile is attached.