Abstract
Strength properties of sandstone prepared in cylindrical specimens with different moisture contents were studied using triaxial compression test under confining pressure in the range of 0 to 80MPa. It is shown that the relations between strength and confining pressure are generally non-linear, and the non-linearity depends on the moisture content of specimen. In order to express these strength properties of sandstone, Lade's failure criterion for soil with curved failure surfaces was extended for including the tensile strength in the criterion and was applied to the test results. As the results, it may be concluded that this failure criterion is available for rock as well as for soil when the value of material parameter related to tensile strength is determined from the uniaxial tensile or compressive strength.
