A 2D lattice approach to describe hydraulic fracturing is presented. The
interaction of fluid pressure and mechanical response is described by Biot's
theory. The lattice model is applied to the analysis of a thick-walled
cylinder, for which an analytical solution for the elastic response is derived.
The numerical results obtained with the lattice model agree well with the
analytical solution. Furthermore, the coupled lattice approach is applied to
the fracture analysis of the thick-walled cylinder. It is shown that the
proposed lattice approach provides results that are independent of the mesh
size. Moreover, a strong geometrical size effect on nominal strength is
observed which lies between analytically derived lower and upper bounds. This
size effect decreases with increasing Biot's coefficient