Cavity expansion–contraction-based interpretation of pressuremeter tests in sand

Abstract

Soil states inferred from solely pressuremeter loading curve are significantly affected by installation, while the utilization of pressuremeter unloading curve is particularly attractive because of providing more reliable results. In this paper, a novel cavity expansion–contraction-based interpretation method for complete pressuremeter loading–unloading curve in sand is proposed with an advanced optimization. To provide efficient theoretical basis for the interpretation, an exact solution for drained cylindrical cavity contraction after expansion in sand characterized by a critical state-based model is proposed employing an explicit hybrid Eulerian–Lagrangian (HEL) method, which is validated against numerical results. Consequently, an interpretation method for pressuremeter loading–unloading curve in sand is developed based on the proposed solution, enabling back-calculations of the effective horizontal stress, the state parameter and other soil parameters through the covariance matrix adaption evolution strategy optimization. The validity of the developed method is verified against two virtual tests, and six laboratory and field pressuremeter tests in different sands. Furthermore, field pressuremeter tests at two sites are selected to examine the applicability of the proposed method, demonstrating its great capabilities in evaluating sand properties with a comparison to results derived from other methods.