METHOD OF GROUND EXAMINATION BY ELASTIC WAVE BY MAKING EACH GROUND LAYER BOUNDARY FACE IN HOLE AS VIBRATION GENERATING POINT

摘要

PURPOSE:To examine at a deep portion in cities or a small area by employing a boring hole for examination of gound and nonexplosion earthquake source. CONSTITUTION:In boring holes 1, 2 for examination of ground pracitced at a suitable interval, ''air gun'' as a nonexplosion earthquake source, and an underwater earthquake receiver 12 are inserted, and a number of earthquake receivers 9 placed on a ground surface are connected to a recorder 14 through an amplifier 13. Then the vibration is carriedout by the air gun 3, the generated elastic wave propagation is along a layer face transmitted, confronted, bent and reached to the ground surface to be converted to an electric signal by the vibration receivers 9, amplified and recorded. Thus, if reading indicating the time from the time base indicating the instant of the vibration generation to the first movement of the respective wave motion, a travel time curve showing the relation between the distance and the time can be obtained and by analyzing it, thus the ground condition is detected.