| Mobile soil and rock avalanches arise from slope failure in a variety of geological and geomorphological settings.; In this thesis the mobility of soil and rock avalanches is examined on the basis of the concepts of liquefaction and steady state of deformation. Comminution theories are referred to for understanding the disintegration of rock and the formation of fine-grained materials. Liquefaction is proposed to account for the reduction of shearing resistance of the fine-grained debris, thus, leading to mobility.; A sliding-consolidation model is developed to predict the characteristics of movements (run out distance, velocity distribution etc.). The factors that control mobility are identified. It was shown that consolidation is unimportant. Slope reduction alone then, accounts for movement deceleration.; Liquefaction is found to play a fundamental role in the mobility of the landslides. Experimental work is conducted to explore some relevant aspects of liquefaction concerning the Steady State Line. It is shown that for soils with grains of the same nature the relative position of the SSL is a function of the coefficient of uniformity with all SSL's parallel.; Parametric analyses are conducted with the main purpose of identifying the relevant parameters controlling the mobility of the sliding mass.; Matching of movement history of real cases is used to show the validity of the model. Data concerning the history of movement published in the literature are analysed and compared with those determined by the application of the present model. The remarkable agreement between the predicted values and those recorded in the literature illustrates the validity of the model and gives support for its utilization as a predictive tool for the determination of the characteristics of the dynamics of flows. |
