Revised Shear Strength Model for Infilled Rock Joints Considering Overconsolidation Effect

Revised shear strength model for infilled rock joints considering overconsolidation effect. B uddhima Indra1'lltnll. DavidA. F. Oliveira, Mylvaganam Jayanathan, An infilled rock joint is likely to be the weakest plane in a rock mass. The most pronounced effect oj the presence of infill material is to reduce the friction of the discontinuity boundaries (i.e. rock to rock contact of thejoint walls). The thicker the infill the smaller the shear strength of the rock joint, and once the infill reaches a critical thickness, the infill material governs the overall shear strength and joint walls (rock) play no significant role. However, some infilled joints may gain strength over time due to consolidation mechanisms, but may be weakened upon subsequent joint movements. Several models have been proposed to predict the peak shear strength of infilled joints under both constant normal load (CNL) and constant normal stiffness (CNS) conditions, taking into account the ratio ofinfill thickness (t) to the height ofthe joint wall asperity (a), i.e. tla ratio. CNS models provide a much better accuracy ofthe infilledjoint behaviour i