Integrating AutoCAD with Finite Element Code to Model Underground Construction

The use of AutoCAD 10 allow easy interaction with a 3D nonlinear finite element (FE) excavation code DIG-DIRT written by the PI is presented. DIG-DIRT currently has many advanced features such as the element birth/death option to model the placement/removal of new/old materials, fluid flow option, consolidation with free-surface seepage, nonlinear soil behavior, and geometric nonlinearity options. However, DIG-DIRT has limited input/output capabilities. The current AutoCAD model allows the user to input the problem, run DIG-DIRT, and view the results (displacement, pore pressures, stresses/strains) all from within AutoCAD. The current model also allows the user to view the output results at different time steps during the excavation sequence. This is essential since the process of excavation involves sequential removal of earth materials and installation of new structural members Enhancing DIG-DIRT, by adding a user-friendly interface such as AutoCAD, will make the advanced features accessible to the design and construction community.