Determination of in-situ stresses within rock masses using the acoustic emission technique

Abstract

The use of acoustic emission as a technique for in-situ stress measurement was investigated. The process was based on two maxims: 1) the existence of the Kaiser Effect, and 2) the directional response of acoustic emissions to a stress field. During the study different rock types were loaded in the field with the aid of a Goodman Hard Rock Jack, as the resulting acoustic emissions were monitored. The results of this study indicate that the technique has the potential for determining the in-situ stress field. The Kaiser Effect was found to exist in small samples of granite under unconfined compression. Signs of this phenomenon were also observed in the field. A directional behavior suggesting different AE levels in response to a stress field was also observed in the field testings for the granite.