A serious consequence of earthquake-induced strong ground shaking is the potential soil failure known as liquefaction. In order to arrive at a thorough understanding of this phenomenon, and to formulate and calibrate analytical techniques to predict the occurrence of liquefaction and its effects, data has to be measured at instrumented sites where the in-place soil properties have been appropriately established, and where ground motions have been recorded for an earthquake strong enough to have generated significant increases in the pore-water pressures. Several sites around the world (e.g., Treasure Island in California) are instrumented with accelerometers and pore pressure transducers . The pore pressures recorded at the Wildlife liquefaction site in California during the 1987 Imperial Valley earthquake, and subsequent investigations into the in-situ dynamic behavior of pore pressure transducers, demonstrated the need to develop a reliable pore pressure transducer design.
The goals of this research program are: (1) to refine and improve the design and construction of a piezometer recently developed at the California Institute of Technology (known as the "Caltech" piezometer); (2) to refine the piezometer field installation and in-situ calibration methods, (3) to provide standard methods and guidelines defining the minimum requirements for the design, preparation, installation, and follow-up in-situ calibration and maintenance of piezometers; and (4) study the correlation between pore pressures generated in a saturated granular soil and the liquefaction potential.
Following successful testing, two prototype piezometers will be constructed and installed at the Treasure Island National Geotechnical Experimentation Site, close to the existing pore pressure transducers, to provide (1) additional instrumentation, and (2) a direct performance comparison during future earthquake shaking of the "Caltech" transducer and the existing transducers.
This project is being coordinated with a complementary research program headed by Prof. Pedro de Alba at the University of New Hampshire.
