DISCRIMINATING METHOD OF GEOLOGY

PROBLEM TO BE SOLVED: To reliably discriminate a change in the geology by acceleration data, and accurately recognize an arrival at the geology of a water impermeable layer or the embedment ground by arranging a piezoelectric element type accelerometer in a hollow part of a rod having an excavating head. SOLUTION: An excavating head 4 where bits 3 are implanted on the tip of a rod 2 is arranged on an auger 1. A piezoelectric element type accelerometer 5 housed inside a protective tube 6 is fixed to the vicinity to the excavating head 4 of a cement milk flowing passsage in the rod 2. In the piezoelectric element type acceleromemter 5, mass and a piezoelectric element are arranged in a case, and a phenomenon that electric charge in proportion to a change in the mass is generated since the mass is displaced to the case and applies force to the piezoelectric element when acceleration acts on the case, is utilized. Imapct and vibration are expressed by a variation per unit time of displacement, speed and acceleration. Since resistance to vibration, rotational tirque and rotating speed applied to the excavating head 4 becomes different in a geological condition of respective strata, and an arrival at the geology of the water impermeable layer or the embedment ground can be known by discriminating the geology.