Constant-Volume Cyclic Testing to Determine Input Parameters for the GMP Pore Pressure Generation Model

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Conference Proceeding

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The GMP (Green, Mitchell and Polito) pore pressure generation model uses the energy dissipated in a soil during cyclic loading to predict the residual pore pressure rise in a saturated soil subjected to cyclic loading. In addition to the shear stresses and shear strains applied to the soil deposit being modeled, the GMP model requires a single calibration parameter referred to as the “pseudo energy capacity” or “PEC”. The study reported in this paper examined the validity of using constant-volume cyclic simple shear tests to develop values of the PEC for input into the GMP model. The study performed consisted of using the PEC developed from a series of constant-volume cyclic simple shear tests performed on a loose sand to predict the residual pore pressures generated during a series of stress- and strain-controlled cyclic triaxial tests performed on the same sand prepared to the same density. It was found that once the pseudoenergy capacities from the constant-volume cyclic simple shear tests were scaled to account for the effects of specimen size, they did an excellent job of predicting the pore pressure generation that occurred during the cyclic triaxial tests.


Presented at the GSP 281 Geotechnical Frontiers 2017: Seismic Performance and Liquefaction, Orlando, Fla, March 2017. pp. 71-79.