Subsoil survey by ae methd

Abstract

Abstract PURPOSE: To accomplish an accurate and quick measurement by arranging a number of AE detection sensors in a hole in the direction of depth when pressure resistance or the like of subsoil is measured depending on the pattern of an acoustic emission (AE) generated with the application of a stress to the layer. CONSTITUTION: In a subsoil survey, first sensors 5aW5z are inserted into a hole 1 at a proper interval. Then, the opening of the hole is sealed up with a packer 2 and a mud is forced into the hole 1 with a liquid injector 4 to apply a stress to the layers. As a result, an AE comes from the layers according to the pressure resistant characteristics thereof. They are detected with individual sensors 5aW5z and transmitted separately to a recorder 7 by way of a signal processing circuit 6 to record. For example, this recording can be so designed as to make a property diagram which indicates changes in the occurance of AE per unit time (AE occurence rate δ) released when a gradually increasing stress is applied to a certain layer with the passage of time. In the drawing, the pressure resistant characteristics of the layer is estimated from the magnitude So value of the stress at the point B. COPYRIGHT: (C)1981,JPO&Japio

Inventors

• 👤 Kiichi Tanimoto
• 👤 Isao Nishii

Bibliographic Details