Hydrogeology-Induced Retrogressive Slope Toe Failure Initiation: A Coupled Physical and Numerical Modeling Approach

The conceptual premise of the current study is that the chronological effect of geologic parameters and hydrologic variation has been enhancing the toe slope since then, and hence the natural slope has remained stable. To capture the phenomenon, in addition to an intensive literature review and the subsequent findings and rationales, comprehensive laboratory testing, physical flume experiments, and numerical modeling were performed. The flume experiments were extensively instrumented (pore pressure transducers, suction sensors, strain transducers, and tracer chemicals) to observe the retrogressive failure mechanism. The results show that the abrupt change in slope toe stress caused by an increase in slope angle, rise in pore water pressure, and dissipation of soil suction were responsible for radical change in strain and sudden failure. Findings show that the slope toe section was the spot of failure initiation and was subjected to sudden failure associated with accelerated retrogressions. Physical flume assessment and numerical simulations both show that modifying the slope toe could increase overall slope stability. Hence, slope toe contributes far more to slope stability than previously thought. Even though the soil type range and slope angle at which the retrogressive failure occurs remain a source of considerable ambiguity, proper slope toe treatment can be regarded as a critical remedy measure.