ANISOTROPY OF WADI-LISB MARBLE

Anisotropy in rocks substantially affects its engineering properties. Anisotropy is more to be expected in metamorphic and sedimentary rocks due to the presence of foliation or bedding. In addition, mechanical weathering in arid areas also induces anisotropy in most types of rock s. Wadi Lisb marble has been investigated at an earlier stage of its e xploitation and was found to contain microfissures parallel to the reg ional foliation trends. This investigation was performed on deeper lev els with better quality marble. The investigation revealed, to some ex tent, the effect of foliation or microfissuring orientation angle on t he engineering properties of the marble. The obtained U-type deformati on indicated the presence of one direction of microfissuring. The modu lus of elasticity curves show the U-type form and an overall decrease in values as measured with the gauges mounted along the strike of the discontinuities. The Poisson's ratio, on the other hand, showed a high ly scattered relationship. However, the overall values measured with s train gauges mounted along the line of true dip of the discontinuity p lanes are lower than those measured with gauges mounted along the stri ke. The variation in the orientation angle showed no effect on the dyn amic properties of the Lisb marble. The U-type behavior of the Lisb ma rble and the improvement in its physical properties indicate a simple form of discontinuity and consequently an improvement in its quality. As the marble has only one direction of weakness, the orientation of t he cut blocks could be selected accordingly.