JPS61142216A - Calculator for kinetic supporting capacity of pile being driven - Google Patents

Abstract

PURPOSE:To simply and quickly obtain the kinetic supporting capacity of a pile by a method in which an acceleration meter is attached to the head of a pile, and acceleration signals from the meter are sent to a computer center by FM or AM. CONSTITUTION:An acceleration measurer 20 consisting of an acceleration meter 21, a telemeter outgoing device 24, a DC power source 22, and a strain gauge 23 as needed is attached to the head of a pile. Acceleration signals of the pile head, measured by the meter 21, are modulated into FM or AM by the device 24 and sent to a computer center 30. In the center 30, the signals are received by a telemeter receiver 31, modulated into digital signals by a transient recorder 32, and put in a personal computer 33. In the computer 33, the acceleration of the pile head is integrated two times to obtain displacement, and the displacement is figured into an equation for calculating the kinetic supporting capacity of the pile to obtain the kinetic supporting capacity of the pile.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of a dynamic support force calculation device for piles during pile driving.

[Conventional technology]

Generally, when driving steel pipe piles, concrete piles, etc. using a diesel hammer, hydraulic hammer, etc., the following one-dimensional wave equation is used to calculate the bearing capacity of the pile at a predetermined design depth.

Here, RU: Ultimate bearing capacity of the pile A: Actual cross-sectional area of the pile B: Young's modulus of the pile S: Amount of penetration of the pile K: Amount of rebound of the pile N: Average N value of the pile surface U: Perimeter of the pile, KS: Rebound amount of tip ground KO = Rebound amount due to antibody elasticity l: Length of pile eO: Correction coefficient ef: p One of the input path values to the above -dimensional wave equation used for calculation of Amount of penetration at the pile cap.

These are numerical values that indicate the displacement of the pile head, such as the amount of rebound, the amount of rebound due to the elasticity of antibodies, and the amount of rebound at the tip of the ground.

Two methods have been used to determine the displacement of this pile head: a pasted paper method and an optical displacement method.

Figure 4 is a front view and a side view showing the configuration of the pasting paper method. As shown in the figure, graph paper (2) is pasted to the pile (1) with cellophane (3), and the displacement of the pile head is measured by the pillar ( Figure 5 shows the record of the graph paper (2) with the pencil (5) attached to the graph paper (6).

Figure 6 shows the configuration of the optical displacement method and a partially enlarged view of the structure, and shows the displacement of the pile (1) when a target (force) is attached to the pile (1) and a hammer (8) hits it. A camera (9) equipped with a telephoto lens α is used to capture the target (7).
), and the signal is amplified by amplifier I and recorded by recording device @0. FIG. 7 is a graph showing an example of this measurement. Note that α9 is an output device.

[Problem that the invention seeks to solve]

Incidentally, there are two conventional methods for measuring the displacement of a pile head, but each method has the following problems. That is, in the case of the pasted paper method, (1) - It is necessary to reset the pencil after each impact, which poses a danger to the operator.

■The pillar (4), which should be a fixed point near the driven pile, moves due to vibration during impact, resulting in poor measurement accuracy.

■The classification of S, Ks, and Ko required for dynamic bearing capacity calculation is unclear.

Regarding the optical measurement method, ■Measuring equipment is expensive.

■The fixed position of the camera needs to be a fixed point, but in the case of construction on land, it needs to be at least 50 meters away from the pile to prevent driving vibration. Furthermore, it is difficult to obtain a fixed point during construction at sea.

■If the target attached to the antibody shifts, measurement becomes impossible.

etc.

The present invention aims to provide a driving pile dynamic bearing force calculation device that is relatively inexpensive and can guarantee accuracy, solving the problems of the conventional method as described above.

[Means for solving problems]

In the present invention, in order to determine the displacement of the pile head, instead of directly measuring the amount of displacement itself, a method is adopted in which the acceleration of the pile head caused by the pile driving hammer is measured and this is integrated to determine the displacement. .

Therefore, an acceleration measuring device is attached to the pile cap and consists of an accelerometer, a telemeter transmitter, a DC power source, and a strain gauge if necessary, and is installed at an arbitrary point several tens of millimeters away from the pile driving point. Telemeter receiver, transient recorder, computer, synchroscope, X
-Y recorder, C) LT display device, printer, and calculation center consisting of 70 disks.

[For production]

Since the pile dynamic support force calculation device according to the present invention is configured as described above, the acceleration of the pile head is measured by the accelerometer attached to the pile head, and this is modulated into FM or AM by the telemeter transmitter, and the calculation center Send to. At the calculation center, this analog pg signal received by a telemeter receiver is converted into a digital signal by a transient recorder, the acceleration is integrated twice in a computer to obtain the amount of displacement, and this value is converted into a one-dimensional wave equation along with other parameters. By incorporating this into the formula for calculating the dynamic bearing capacity of a pile, the dynamic bearing capacity of the pile can be immediately determined. Note that if necessary, the acceleration waveform received at the calculation center can be displayed on the cathode ray tube of the synchroscope.

In addition, the calculated dynamic support force of the pile can be viewed on a CRT display device, printed on a printer, or stored on a floppy disk.

[Embodiments of the invention]

FIG. 1 is a block diagram of a dynamic support force calculation device for a pile showing an embodiment of the present invention.

- in the figure is a pile cap acceleration measurement device attached to the pile cap +21+
is an accelerometer, (2) is a DC power supply, (c) is a strain gauge, C
41 is a telemeter transmitter, and C is FM or AM.

Also, ■ is the pile dynamic bearing capacity calculation center, Oυ is the telemeter receiver, 02 is the transient recorder, □□□ is the computer, (34) is the synchroscope, G9 is the X-Y Korg,
(to) is a CRT display device, (3'rI is a floppy disk.

In the above acceleration measuring device (A), the electric signal indicating the acceleration of the pile head measured by acceleration #Qυ is modulated into FM or AM by the telemeter transmitter 04 and sent to the calculation center.

In the calculation center, the acceleration signal sent by FM or AM from the telemeter transmitter C24) of the acceleration measuring device is received by the telemeter receiver l31), converted into a digital signal by the transient recorder C33, and then sent to the computer. Input it into PC n, divide the acceleration of the pile head into two equal types to find the displacement, and enter this along with other specifications into the formula for calculating the dynamic bearing capacity of the pile obtained from the one-dimensional wave equation to calculate the dynamic bearing capacity of the pile. Calculate.

The received acceleration waveform can also be visually observed using a synchroscope (b). In addition, the dynamic bearing capacity of the pile calculated by the PC Q can be viewed visually on a CRT display device (see above), printed on a printer (07), or stored on a 70 disk (see below). be.

In addition to the accelerometer, a strain gauge (c) is also installed, so it is possible to measure not only the acceleration of the pile head but also the strain if necessary.

It is also possible to graph numerical values calculated on a personal computer using the X-Y recorder.

Figures 2 and 3 show this, with Figure 2 being a test device and Figures 3 (a), (b), and (C) its graphs.

In Figure 2, the fixed beam (4!9) is made of fla (201EIIφX 1,5
0011El ) +7) Pile (41) A steel (63
, 2mmφX 150val) Nohan vQ3r pile (
The acceleration generated in the pile (41) when the tip of the 4υ is struck is measured with an accelerometer (43), and the value is recorded on a computer (
Fig. 3(a) shows a graph of the velocity and displacement obtained by integrating the velocity and displacement using the X-Y recorder.

Shown in (b) and (C). In Figure 3 (C), curve A is the displacement determined by integrating acceleration, and curve lfMB is the displacement determined by an optical displacement meter, but the method of calculating from acceleration is also accurate enough for practical use. It turns out that there is no guarantee.

〔Effect of the invention〕

In pile driving work, the present invention attaches an acceleration measuring device to the pile head, sets up a calculation center at an arbitrary position several tens of mN1 from the pile driving position, and calculates the acceleration signal from the acceleration measuring device using FM or AM. Since the information is configured to be sent to the center, the following excellent effects can be achieved.

(1) The accuracy of the measured displacement is high.

(2) The dynamic bearing capacity of a pile can be easily and quickly determined.

(3) Since wireless remote measurement is used, there are fewer security concerns.

(4) No fixed point is required.

(5) Since it is a wireless remote measurement method, it can be used regardless of whether it is on land or at sea.

(6) It is relatively inexpensive.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a pile support force n measuring device showing an embodiment of the present invention, Fig. 2 is an explanatory diagram of a test device for measuring acceleration, Fig. 6 (a), (b), (C) is a diagram obtained using a test device. Figure 4 is a front view and side view of the conventional pasted paper method, Figure 5 is a diagram showing the amount of displacement determined using this method, Figure 6 is a configuration diagram of an optical displacement meter, and Figure 7 is a diagram showing the amount of displacement determined using this method. FIG. 3 is a diagram showing a displacement lid. In the figure, @ indicates the entire acceleration m device attached to the pile head, (21)
is an accelerometer, (c) is a DC power supply, (c) is a strain gauge, (
2) is a telemeter transmitter, (c) is FM or AM, fi
is the calculation center, Gυ is the telemeter receiver, G) is the transient recorder, eel is the personal computer, (b) is the synchroscope, (to) is the X-Y recorder, (to) is the CRT display device 1, On is the printer, ( C) is a floppy disk. Agent Patent Attorney Sanro Kimura Figure 1 2+, 22 25mi Figure 2 Figure 3 (9s/den) ) Hiroshi 1 suit N (D (0? N CQ (to Q dimension. ′ = −-ooo (uILu) Figure 4 (a) (b) Figure 6 Figure 7 Figure 1, Incident display% Application No. 59-260631 2, Name of invention Dynamic bearing capacity calculation device for driven piles 3, Relationship with the case of the person making the amendment Patent Applicant name (412) Bhon Steel Tube Construction Co., Ltd. (Name) 4. Agent (1) Amend the scope of claims as shown in the attached sheet. (2) No. 1 of the specification Page 1, line 17 “...Dynamic bearing capacity of piles・
..." is corrected to "...the dynamic bearing capacity of the pile...". (3) In the third line of page 2 of the specification, "7 using a -dimensional wave equation" is replaced with "...using a formula for calculating the dynamic ultimate bearing capacity of a pile obtained from a -dimensional wave equation." ” he corrected. (4) Page 2, line 6 of the specification, rRu: Ultimate bearing capacity of the pile.”
is corrected as rRu: dynamic ultimate bearing capacity of the pile. (5) Line 10 of page 2 of the specification, “K: Rebound amount of pile” shall be deleted. (6) Page 2, line 18 of the specification [...to the above - arrow wave equation] is changed to "...to the above dynamic ultimate support force calculation formula"
and correct it. (7) In the specification, page 2, line 20, "rebound amount, elasticity of antibody..." is corrected to "elasticity of antibody...". (8) Page 4, line 8 of the specification “...Required S, K
. K8 + KO's' to '...required S r K8 +
KO's,'' he corrected. (9) In the fourth line of page 6 of the specification, "...Analog signals and transients" is corrected to "...Analog signals are transients." (To) Page 6, line 12 of the specification, “The calculated dynamic bearing capacity of the pile is...” is changed to “The calculated dynamic bearing capacity of the pile is...”
"..." is corrected. Alpha sword Page 7, line 18 of the specification "The formula for calculating the dynamic bearing capacity of the pile obtained..." is changed to "The formula for calculating the dynamic bearing capacity of the pile obtained..."
and correct it. (6) In the second line of page 8 of the specification, “The calculated dynamic bearing capacity of the pile, etc.” was changed to “The calculated dynamic bearing capacity of the pile, etc.”
” he corrected. (To) Page 8, line 9 of the specification, "Also, using an X-Y recorder..." has been changed to "Also, using an X-Y recorder (To)..."
"..." is corrected. α4 In the specification, page 10, line 3, "...Dynamic support capacity of piles" is corrected as "...Dynamic support capacity of piles." The above appended claims (after amendment) In pile driving work, an acceleration measuring device comprising a calo-speed meter attached to a pile head, a telemeter oscillator, a DC power source, and a strain gauge as necessary; A telemeter receiver, a transient recorder, a personal computer, a synchroscope, an X-Y recorder, and a CRT display device installed at an arbitrary point several tens of meters away from the pouring site.
A dynamic bearing capacity calculation device for driven piles, comprising a calculation center consisting of a printer and a floppy disk.

Claims (1)

[Scope of Claims] In pile driving work, an acceleration measuring device comprising an accelerometer attached to the pile cap, a telemeter transmitter, a DC power source, and a strain gauge if necessary; A telemeter transmitter, a transient recorder, a personal computer, a synchroscope, an X-Y recorder, and a C
A dynamic bearing capacity calculation device for driven piles, comprising an RT display device, a calculation center consisting of a printer and a floppy disk.