Coupled Effects of Pore-Water Pressure Evolution, Slope Curvature, and Mass Variation on the Kinematics of Rapidly Sliding Fine-Grained Materials

The analysis of the complex kinematics of fine-grained masses, from the moment they rapidly slide along mountain streams until they stop, is crucial to the identification of potentially vulnerable areas and the design of adequate mitigation structures for their protection. For this purpose, the speed evolution and runout length of these material flows were analytically modeled in this research by taking into account (1) the (curved) geometry of the sliding surface; (2) the evolution of the excess pore-water pressures (generation, initially attributable to several factors/phenomena and during the motion to the slope curvature, coupled to undrained and oedometric conditions; dissipation, attributable to consolidation); (3) the physical and mechanical parameters of the sliding material; and (4) the mass variation attributable to possible erosion or deposition processes. The governing ordinary differential equation was analytically and numerically solved. The role played by the main parameters in the kinematics of rapid fine-grained material flows and the range of their admissible values were evaluated. Model validations using laboratory measurements and the analysis of specific documented cases were developed and carried out. (C) 2017 American Society of Civil Engineers.