The research component of this CAREER project aims to fill gaps in the methods for geotechnical site characterization. The focus is on overcoming shortcomings in both the experimental and computational aspects. With regard to the experimental component, the primary impediments concern the high cost of deployment of a grid of multiple sensors at a site, and the lack of wide frequency spectrum exciters. With regard to the computational component, it addresses the bottleneck in geotechnical site investigations arising primarily from problems with methods for the solution of the dynamic inverse problems. To this end, the project will utilize the NEES (Network for Earthquake Engineering Simulation) mobile shakers at the University of Texas-Austin. This is combined with the use of recent advances in partial-differential-equation-constrained optimization methods that permit the systematic treatment of either time-dependent or time-harmonic inverse problems. Given the advances in hardware architectures, it is conceivable that large sites can be profiled by on-site, near-real-time processing in the next 4 to 5 years; this constitutes the ultimate target of the research program.
The aim of this CAREER program is: a) To develop the capability for the site-specific rapid imaging of the skeletal properties of a soil mass by coupling in-situ non-invasive experimental and computational methods; b) to develop the computational framework and experimental protocols that will allow near-real-time profiling of large sites, including in-situ adjustments of field arrays to optimize inversion procedures; c) to develop the methodology for profiling soil near-surface and in-depth by exploiting both micro-tremor records and active-source records; d) to seek to validate the approach by profiling a local site; and e) to migrate to the educational curriculum the experimental and computational techniques to be developed, aiming at training the next-generation of engineers in seismic hazard mitigation.
The project addresses a problem central to on-going seismic modeling endeavors that aim at the mitigation of seismic hazards, with far-reaching and clear societal benefits. Beyond this, a successful outcome will have broad implications to a wide range of problems of practical interest to geotechnical and earthquake engineers, while opening the possibility for remote robot-driven site characterization. The PI plans to involve under-represented groups in the research activities, while the educational plan aims to broaden the traditional civil and geotechnical training program with the multi-disciplinary content of the research program. Outreach activities are planned that target both the general public and high school students.
