The formulation of any specific boundary value problem in geomechanics is greatly facilitated firstly by considering the specific attributes as they pertain to the geometry of the domain of interest. Other aspects of the formulation and solution can also include a consideration of features such as material symmetry and other geometric features of the loading and boundaries of the domain. For example, a two-dimensional plane strain problem involving the surface loading of a halfspace region by a concentrated line load (Figure A.1) is most conveniently formulated with reference to a plane polar coordinate system, whereas the plane strain problem involving surface loading by a distributed loading (Figure A.2) is formulated most conveniently in reference to a Cartesian coordinate system.

Also, referring to Figure A.3, the axisymmetric surface loading of a halfspace region by a concentrated load is most conveniently described in relation to a system of spherical polar coordinates, whereas the axisymmetric surface loading of a halfspace region is best formulated in relation to a system of cylindrical polar coordinates (Figure A.4).

While in the examples cited just previously, the choice of the coordinate system is largely dictated by the mode of loading, there are other situations where the geometrical boundaries of the domain of interest have a decided influence on the choice of the coordinate system.