This Small Business Innovation Research Phase I project is to apply Discontinuous Deformation Analysis (DDA) coupling with the Finite Element Method (FEM) to perform static and dynamic analyses, detailed mechanical response prediction, global stability and failure mode analysis of geotechnical structures for seismic design, construction, and rehabilitation. The research will prototype new commercial software, DDA+FEM - an integrated engineering analysis tool - to conduct excavation safety and rock slope stability analysis, study foundation and structure interaction, perform earthquake simulation, and further, to assist in the seismic design of geotechnical structures. Discontinuity exists in geotechnical structures. DDA predicts the stability and stress associated with a block system containing preexisting cracks and joints. This method was primarily applied in rock mechanics with great success in the stability analysis of tunnels and rock slopes. DDA+FEM improves the block's stress/strain fields by adding a finite element mesh in each block. Therefore, large displacement and deformation problems for numerous discontinuous blocks with detailed stress distribution can be solved. The objectives of this Phase I research project are to design and prototype the 2-D finite element meshed block, and to enhance DDA features with better boundary conditions for direct data input from earthquake records, laboratory or field measurements. DDA+FEM is the engineering tool to effectively perform discontinuous interface analysis of geotechnical structures under earthquake excitation. It can (1) assist designers to perform predictive numerical simulation for preliminary seismic design evaluation and further modification; (2) support field engineers in decision making to ensure global stability of the structures and safety of workers during construction; and (3) reduce the costs of design, construction, and field experiments. If the project achieves its goals, the resulting software will (1) have great application in geotechnical, industries, universities, governments, and national laboratories; (2) have important contributions on hazard reduction of geotechnical structures under earthquake excitation.
