ABSTRACT
As it results from in-situ measurements, the state of stress at shallow parts of the Earth’s crust seldom has the property of axisymmetry. In contrast, even in those regions which are not disturbed by mining or construction operations, the intermediate principal stress can be several times higher than the minimum stress (see Rummel 1986, Stephansson 1993, Amadei & Stephansson 1997, Zang & Stephansson 2010). This is the reason for the necessity of knowing the behavior of rocks not only under axisymmetric but also under asymmetric triaxial stress conditions. Of course, this need becomes even more urgent in engineering applications because the stress field in the vicinity of underground excavations and/or structures becomes even more complex than in undisturbed rock masses.
