A Case Study on the Progressive Failure Mechanism of I-180 Slope Using Numerical and Field Observations

Abstract

A progressive failure of shallow slopes is commonly encountered in eastern Nebraska due to the region’s unique geological and weather conditions. This study presents a case study for a slope in Nebraska that experienced a progressive failure. Emphasis was given to examine the condition and triggering mechanisms of the slope failure through a field observation and numerical modeling. FLAC2D was employed to conduct the numerical simulation of the progressive failure based on a hydromechanical coupled framework. Data from experimental test results were utilized to model the mechanical behavior of the soils. The progressive development of the slip surface, degradation of shear strength parameters, slope displacement, and variation of the local factor of safety with time were analyzed. A similar outcome from the numerical analysis to that of the field observations demonstrated how various strength degradation mechanisms could be integrated into a single numerical analysis to understand the progressive failure of shallow slopes.