HOW DOES THE WATER SATURATION INFLUENCE THE MECHANICAL PROPERTIES OF THE VOLCANIC TUFFS?

Abstract

Different Hungarian volcanic tuffs (andesite tuffs, basalt tuffs and rhyolite tuffs) were investigated with the goal to determine the influence of the water content on their strength. The following petrophysical constants were measured for all the samples both in dry and saturated conditions: bulk density, ultrasonic wave velocity, uniaxial compressive strength (UCS) and Young´s modulus. The destruction work (strain energy) was calculated from the measured stress-strain curves, as well. The influence of the water for the UCS, impedance (scalar of the density and the ultrasonic wave velocity) and the destruction work is shown. In these cases linear relationship can be written between the dry and the saturated constants. Both linear and power equations can be used for the effect of the water on Young´s modulus. Finally the UCS is written as the function of the density and the impedance.