Scholar: Bashar Al-Nimri
When: May 12th, 2026 at 1:00PM
Where: KH A549
Zoom: https://unl.zoom.us/j/91813955432
Title: Piezocone Penetration Test PCPT-based Evaluation of Wet-Drained-Fully Softened (WDFS) Shear Strength of Soil
Abstract: Wet-drained fully softened (WDFS) shear strength has been linked to several slope failures in Nebraska, highlighting the need for reliable field-based evaluation methods. Existing approaches primarily rely on laboratory testing and often do not adequately capture in situ wetting effects or strength degradation under field stress conditions. This study presents a field-based methodology using a revised piezocone penetration test (PCPT) that enables controlled water injection at specified depths, followed by penetration to assess soil resistance under drained conditions. Field tests conducted at multiple Nebraska sites were complemented by laboratory direct shear tests under field moisture and soaked conditions. Results show that water injection leads to substantial reductions in tip resistance and sleeve friction, with shear strength decreases of up to 90%, while near-zero pore pressures confirm drained behavior. Empirical correlations between normalized PCPT parameters and WDFS shear strength were established for practical prediction. An artificial intelligence framework was also presented to capture nonlinear relationships and provide a benchmark for future model development.