Mechanical anisotropy of jointed rock mass under uniaxial compression and tensile loading

Abstract

Anisotropic in a rock mass are the properties which have directional mechanical behaviours. These anisotropic characteristics are originated from foliation of minerals in metamorphic rock, stratification in sedimentary rocks and discontinuities in the rock mass. The strength and deformability of rock mass are influenced by the orientation and distribution of fractured networks and the failure mode is varies significantly with the variation of fracture orientation. Therefore, the mechanical behaviour of rock mass becomes one of the most crucial topics in rock engineering fields. In this paper, stratified and jointed limestone samples from two different quarries of Ipoh areas (LafargeHolcim and Hume Cement) were studied to determine the mechanical strength and failure patterns under uniaxial compression and tensile loading. The results showed that the failure pattern and maximum strength of was correlated with relative layer orientations. It was observed that the higher the inclination angle the lower the failure strength. The maximum tensile strength also observed at 0° with 16.77 MPa and the lowest occurred at 75° which are 5.68 MPa. The highest compression loaded at 0° which to break at 104.81 MPa and the lowest occurred at 75° which are 40.38 MPa. It is suggested that the failure pattern analysis should be considered in mechanical study of jointed rock mass.