Incorporation of measured pore-water pressure readings from Gardiner Dam for 3D deformation modelling

ABSTRACT: A study is currently underway to develop 3D (three-dimensional) finite-volume stress-strain numerical models to enhance the understanding of the Gardiner Dam’s historic and future geotechnical performance. A key input for calibrating such models to the field performance is the accurate replication of historic pore-water pressures (PWP). To do this, PWP distributions were modelled directly from piezometer measurements collected during the construction and operation of the dam. The measured PWPs were inputted at the location of the various piezometer tips with interpolation done between each tip according to the technique developed by De Alencar et al. (1992). Given the observed relationship between PWP spikes with fill placement, PWPs were interpolated between the tips in terms of their 𝐵̅ or 𝑟𝑢 response, rather than absolute pressure. With this methodology, the resulting PWP regime became reflective of the site conditions, and the overall calibration of the model deformations was found to improve.