Book cover Book cover Advances in Transportation Geotechnics IV pp 583–594Cite as Inverse Analysis of a Failed Highway Embankment Slope in North Texas

Abstract

Expansive clayey soils undergo significant volumetric changes, and desiccation cracks develop due to wetting and drying cycles. The presence of desiccation cracks changes the soil's hydro-mechanical properties and allows rapid infiltration of rainwater to the underlying deeper layers. The abrupt increase in moisture content and swelling reduces the soil's peak strength to fully softened strength. Consequently, these slopes experience shallow failures that are approximately parallel to the slope surface. The purpose of this study is to assess the impact of weathering cycles by studying the failed highway embankment slope located in Denison, Texas. The experimental laboratory studies, including direct shear test, fully softened strength test, soil water characteristic curve, and soil hydraulic conductivity tests, were conducted on samples that were collected from scarp of the failed slope. A comprehensive inverse analysis was conducted using a finite element method-based software package. The analyzed results suggest that the surficial slope failure was attributed to (i) the formation of desiccation cracks, (ii) increase in soil permeability, (iii) reduction in shear strength, and (iv) the formation of the perched water table in the weathered surficial soil during intense rainfall events.