PURPOSE: To enable a vibration alone on the basis of excavation to be measured by detecting the rotation of a cutter, analyzing the whole vibration based on the data, and extracting merely a constituent synchronizing with this cutter rotation.
CONSTITUTION: An accelerometer 11 is clamped to the tip of a pipe 6, inputting the signal into a wave analytic circuit 13, and a tachometer 12 is clamped to a rotary motor 7 of a cutter 8. In addition, each output of the wave analytic circuit 13 and the tachometer 12 is connected to an arithmetic circuit 14, and output of this arithmetic circuit 14 is connected to a wave composite circuit 15. In this case, at this arithmetic circuit 14, an integer-fold component alone of cutter revolving speed measured by the tachometer 12 is outputted out of the output of the wave analytic circuit 13. Next, at the wave composite circuit 15, this signal is made into an inverse Fourier transformation, outputting a vibro-waveform in a time domain. Then this vibro-waveform is independent of an external vibro-component, and thereby a soil property is accurately presumable from this waveform.
TAKAHASHI KAZUHIKO
KAWABATA KAZUYOSHI
