An experimental approach for developing an alternative method for determining in situ stress using acoustic emission technique

Abstract

<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">A laboratory investigation was carried out to study the Kaiser effect in Chunar sandstone and its applicability in determining <i>in situ </i>stress by using this technique. The Kaiser effect is a phenomenon whereby acoustic emission (AE) in a rock sample sharply increases when it is stressed beyond the previous maximum stress level. AE signals were observed by using two piezoelectric transducers in suitable frequency range. The hardware and software settings of MISTRAS-2001 were customised for the present investigation. MARSE (measured area under the rectified signal envelop), sometimes known as energy counts, was also considered for the verification of Kaiser effect Chunar sandstone exhibited an obvious Kaiser effect. Felicity ratios (FR) (ratio of load at which emission begins again to previous maximum stress) were also calculated for different Chunar sandstone specimens.</span>