To determine the geology and stratum change in real time with good accuracy by installing an acoustic sensor in a bit of the tip of an auger rod to continuously measure the waveform of the generated drilling sound or boring sound, and analyzing the measurement result.
An acoustic sensor 4 is installed in a bit 3 of the tip of an auger rod 2 of a drilling machine 1 to be inserted in a drilled hole 6, and connected to a ground waveform measuring device 7 and a waveform analyzer 8 by wiring 5. Previously, at the spot of construction, investigation boring or penetration resistance test is made to create a geologic columnar section showing the geologic distribution in the direction of depth, or the waveform data at the time of excavating the ground or the rock. Hereinafter, according to the data, the geological boundary, geology and lithology are determined. The waveform of drilling sound generated at the time of drilling or boring is continuously measured to analyze the amplitude of waveform data by each unit time or each unit depth, and from the change, the geology and stratum change can be determined in real time with good accuracy. Thus, the frequency of boring investigation can be decreased to reduce the cost of determining the geology and stratum change.
ABE TORU
KAMIMURA KAZUYOSHI
