Poly3D is a C language computer program written by Andy Thomas (1993) to calculate the quasi-static displacement, strain and stress fields in a linear-elastic, homogeneous and isotropic whole- or half-space using planar, polygonal elements of displacement discontinuity and the boundary element method (BEM). The elements may have any number of sides, with a minimum of three, and the solution by Comninou and Dunders (1975) for an angular dislocation is used for their construction. Geologically, a polygonal element may represent some portion, or all, of a fracture or fault surface (see figure below). The displacement discontinuity (fracture aperture or fault slip) is constant on each element, but one may use multiple elements to model an arbitrary number of mechanically-interacting fractures or faults with non-uniform opening and/or slip distributions.
The discretization of a fault surface into triangular boundary elements allows the construction of a three-dimensional surface with an irregular tipline and no overlaps or gaps. Boundary conditions include uniform displacement discontinuities on each element, or tractions matched at element centers, and uniform remote stresses or strains. Output includes the displacement vector, and the stress and strain tensors (or any user-defined function of these quantities such as Coulomb stress) on user-defined observation grids.
Many different aspects of Poly3D have been verified by comparisons to analytical solutions from elasticity theory. While we have considerable confidence in the code, the process of verification is on-going and will be enhanced by increasing the user pool. The code has been applied to a wide variety of academic and industry problems, resulting in more than twenty papers published in refereed journals between 1996 and 2002.
Poly3D and Poly3DGUI (academic version) are being developed at Stanford University with support from the U.S. Geological Survey.
Poly3D and Poly3DGUI (industrial version) are being developed at Stanford University with support from the oil and gas companies through the Poly3D/Dynel/GUI Sub-Project of the Stanford Rock Fracture Project.
Copyright © The Stanford Rock Fracture Project 2002