JPS5930007A - Method for measuring sinking state of pile - Google Patents

Abstract

PURPOSE:To measure the sinking state of a pile highly accurately without the effect of the vibration of the ground, by detecting the acceleration of the sinking pile, converting the detected value into a digital value, and performing the double integration of the value. CONSTITUTION:When a pile 1 sinks by striping, an acceleration sensor 3''', which is fixed to the pile 1, generates a voltage corresponding to the acceleration of the pile 1. Said voltage is inputted to a measuring and operating device 7, and adjusted to the voltage, which is proportional to the acceleration of the pile 1 within a specified range. Then the voltage is converted from the analog value to the digital value, and double integration is performed. The value of the result of the double integration is displayed on a display device 8 as the amount of displacement of the pile 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the sinking state of piles that is easy to supervise in construction by using an electronic circuit to measure the sinking state of piles during pile driving using the percussion method.

Fig. 1 shows an example of a conventional measurement method, in which a paper 2 is pasted on the outside surface of a stake 1, a lead etc. 3 is placed along a ruler 4, and the lead etc. 3 is moved horizontally by hand. , the relative displacement with pile 1 is paper 2
This is recorded above and has been widely used for many years, but not only does the ruler 4 itself vibrate due to ground vibrations during pile driving, resulting in low accuracy, but it also causes damage to the hammer and pile under the hammer while the worker is driving it. It had drawbacks such as being located in an extremely dangerous location.

FIG. 2 shows another example of the conventional measurement method, in which a rubber roller 5 is provided in contact with the outer surface of the pile 1 and rotates as the pile sinks, and an intermittent contact or In this method, the displacement of the pile is detected as a change in current or voltage by driving the variable resistor 3', and this is measured by the measuring unit 7. Although the danger to workers has been eliminated, it is difficult to carry out pile driving. The roller 5 slips due to the vibration inside, which has the disadvantage of low measurement accuracy.

Fig. 3 also shows another example of the conventional measurement method, in which a target 2' with the top and bottom painted black and white is pasted on the side of the pile, and as the pile 1 sinks, the visual field of the receiver 3'' This method detects changes in the amount of light reflected by the electrolyte and measures them with the measurement unit 7'.As the target 2' moves as the pile sinks, the range that can be measured is limited, and moreover, the measurement unit 7' There were drawbacks such as vibration due to ground vibration and low detection accuracy.

The purpose of this invention is to provide a measurement method that eliminates the drawbacks of the conventional measurement methods described above. Detects the acceleration of the pile, generates a voltage proportional to the acceleration, converts this voltage into a digital value, double-integrates this value to determine the displacement of the pile, and displays this displacement on a printer or display. This feature is characterized in that it is displayed on the device.

Embodiments of the present invention will be described in detail below with reference to FIGS. 4 to 6.

In Fig. 5, 1 is a stake, 3'' is an acceleration sensor securely attached to the stake 1 so as not to move, and 7 is an acceleration sensor 7.
A measurement calculation device 8 is a display device connected to the measurement calculation device 7, and as shown in FIG. , a memory B16, an arithmetic unit B17, and a printer 18.The output of the acceleration sensor 3'' is connected to the controller 11, and the output of the controller 11 is connected to the impact detector 13 and the A/D conversion unit 12. The outputs of the detector 13 and the A/D conversion unit 12 are connected to the memory A14.

Further, the output of the memory A14 is connected to the arithmetic unit A15, the output of the arithmetic unit A15 is connected to the arithmetic unit B17 via the memory B16, and the output of the arithmetic unit B17 is connected to the printer 18. Note that, as necessary, the output of the calculation unit A15 is connected to the oscilloscope 19 and the hydraulic hammer control device 21, and the output of the memory B16 is connected to the graphic printer 20 or the XY plotter.

When pile driving begins and the pile is struck and sinks, the acceleration sensor 3'' fixed to the pile 1 generates a voltage according to the acceleration of the pile 1. This voltage is directly proportional to the acceleration of the pile 1 by the controller 11. The voltage is adjusted to a certain range and output, and this output is converted into a 4- to 16-digit 2-digit signal by the A/D conversion unit 12.
Output as a base number. This value is 0.03 to 0.1 generated when the impact detector 13 detects an impact in the memory A14.
When a signal lasting for seconds is entered, it is written to memory A14. Arithmetic unit A15 reads the numerical value written in memory A14, performs double integration according to the arithmetic instruction stored in memory C22, and writes this numerical value in memory B16. The calculation unit B17 reads out the numerical values stored in the memory B16, and calculates the amount of sinking S of the pile 1 for each blow, the total amount of sinking ΣS, the amount of rebound R, the total number of hits n, etc., according to the calculation instructions stored in the memory D23. These outputs are sent to printer 18 for printing.

In the above embodiment, in order to view the waveform of the displacement of the pile 1, the output of the calculation unit A15 may be input to the oscilloscope 19, or the numerical values stored in the memory B16 may be input to the graphic printer 20 and displayed. In addition, the output of the calculation unit A15 is guided to the hydraulic hammer control device 21,
If the amount of sinking of the pile 1 is excessive, it can also be used as an input to operate the control device 21 to stop the hammer or reduce the height of the heavy weight.

This invention does not directly detect the displacement of a pile like conventional measurement methods, but instead detects the acceleration of the pile, converts this value into a numerical value, performs double integration, and measures the displacement of the pile. There is no need to set realistic reference values for measurements on ground that vibrates violently, and therefore remote measurements can be made without being affected by ground vibrations, making work not only safer, but also extremely accurate measurements. Can be carried out continuously during enforcement,
Even when carrying out work under water, it has many effects, such as being able to know the sinking situation of piles in the same way as on land.
It can also be used to control the movement of a hammer by inputting it into a machine (No. 0), which is extremely useful.

[Brief Description of the Drawings] Figures 1 to 3 are schematic diagrams of three examples of conventional measurement methods. FIG. 4 is a block diagram of one example of the measurement method of this invention. FIG. 5 is a schematic diagram of one example of a measuring device used in the present invention. FIG. 6 is a graph showing the behavior of the pile. 1...Pile 11...Controller 2...
Paper 12...A/D conversion unit 2
'...Target 13...Impact detector 3...Pencil
14...Memory A3'...Intermittent contact or 15...Arithmetic unit A variable resistor
16...Memory B3''...Receiver 17...
Arithmetic unit B3'''... Acceleration sensor 18... Printer 4... Ruler 19... Oscilloscope 5... Roller 20... Graphic printer 7... Measurement calculation device 21... Hydraulic hammer control device 7'... Measurement recording device 22... Memory C8
...Display device 23...Memory D patent applicant
Tadahiko Miura

Claims (1)

[Claims] The acceleration of the pile sinking due to the impact force of the pile driving stamp is detected, a voltage proportional to the acceleration is generated, this voltage is converted to a digital value, and this value is double integrated to determine the amount of displacement of the pile. This displacement amount is displayed on a display device such as a printer or a display.
Method for measuring pile settlement status.