Research on the movable solid materials under seepage flow effect in debris flow source area, The

Abstract

Solid materials distributed on the surface of watershed transform to debris flow under seepage flow effect is one of the most common disaster type in the mountainous area, especially in the Longmen Fault regions, China. The high frequency of debris- flow event takes a big menace to local people’s safety of life and properties directly, as well as the reconstruction work. Currently, more theory and experiment researches are concentrated on solid materials instability mechanism, debris-flow initiation, movement process of slope-gully system, but fewer research are focused on the moveable critical condition of solid materials under hydrodynamic condition as seepage flow and surface flow. Thus, based on the mechanical balance, through define the theory of the movable solid materials firstly. Then, take a comparison with traditional terms as loosen solid materials, dynamic reserves and efficient solid materials, it found that solid materials move or not is a mechanical problem rather than traditional definition. Thirdly, on the condition of saturated seepage flow, according to setting up geological model and taking mechanical analysis, it gained dynamical formula and resistance formula respectively, then, give confined parameters, it found a liner distribution of dynamical value and resistance value versus depth when the geology model is homogeneous and the seepage flow saturated in whole layer.