ABSTRACT
This contribution discusses the question of how to distribute stress measurements made in situ to the adjacent rock mass. In this regard, the distinction between state of stress and stress field is often obscured in discussion of stress measurement. The main reason is the common practice of tacitly assuming that the two are the same in the rock mass outside any region influenced by excavation. The same assumption is often reflected in boundary conditions used in numerical modeling where uniform (constant) tractions or displacements are applied well away from the excavation. Only if the rock mass is homogeneous and the regional stress field is slowly varying, is the pre-excavation stress field simply approximated as the measured stress. Otherwise when the rock mass contains several rock types and is jointed and faulted, the pre-excavation stress field is complex. Nevertheless, a common practice is to distribute the same measured stress state throughout the region of interest and analysis. Although this practice is occasionally questioned, a rational procedure is apparently lacking.
