Strength behaviour of a model rock intersected by non-persistent joint

Abstract

Several constructions in the field of civil engineering quite often need to deal with rocks. Strength behaviour of rock intersected by a discontinuity or a set of discontinuities has been a topic of keen interest for engineering community. The popular attributes of discontinuities that have been given due importance are their frequency, orientation and surface characteristics. Non-persistency, however, has been given little attention. This article presents an experimental study wherein focus has been made on the effect of non-persistency of the joint on the uniaxial compressive strength (UCS) of a model rock for various geometries such as orientation, discontinuity length ratio and number of joint segments. The applicability of single plane of weakness theory (SPWT) to assess the strength of jointed specimens has also been evaluated. It has been noticed that SPWT captures the strength behaviour only for a narrow range of discontinuity orientations. As an improvement, an approach is suggested by extending concepts of degree of persistence and joint factor to have a better understanding towards strength behaviour of rocks intersected by non-persistent joints. Keywords: Uniaxial compressive strength (UCS), Joint segment, Non-persistency, Joint factor