Publications

This paper presents a comparison study between two in situ stress measurement techniques based upon stress-relief microcracks: differential strain analysis (DSA) and ultrasonic shear wave splitting (USWS). This study is based on a fact that the importance of in situ sh-ess information has been increasingly realized in recent years. Various subsurface engineering activities such as those in petroleum and geothermal exploitation are dependent on a proper knowledge of this parameter. Therefore, there is always a continuing need to find and develop techniques for determining this important parameter. A contribution to the development of the relatively new concept of USWS laboratory technique has been made by comparing USWS measurement results from ten rock samples taken from deep boreholes with results from the more established DSA technique using the same rock samples, as well as with results from sleeve fracturing obtained from the same area. The comparison results have proved USWS as a reliable technique for determining trends of in sztu stresses, and combined utilisation of the two techniques have also proved useful for examining rock microstructural features.