Mutual interference of two debris flow deposits delivered in a downstream river reach

Abstract

We investigate experimentally the\ud depositions of two contiguous debris flows flowing\ud into a main river reach. The aim of the present\ud experimental research is to analyze the geometry and\ud the\ud mutual interactions of debris flow deposits\ud conveyed by these tributaries in the main channel. A\ud set of 19 experiments has been conducted considering\ud three values of the confluence angle, two slopes of the\ud tributary, and three different triggering conditions\ud (debris flows occurring simultaneously in\ud the\ud tributaries, or occurring first either in the upstream or\ud in the downstream tributary). The flow rate along the\ud main channel was always kept constant. During each\ud experiment the two tributaries had the same slope\ud and confluence angle. The analysis of the data\ud collected during the experimental tests indicates that\ud the volume of the debris fan is mainly controlled by\ud the slope angle, as expected, while the shape of the\ud debris deposit is strongly influenced by the confluence\ud angle. Moreover, in the case of multiple debris flows,\ud the\ud deposit shape is sensitive to the triggering\ud conditions. Critical index for damming formation\ud available in literature has been considered and\ud applied to the present case, and, on the basis of the\ud collected data, considerations about possible\ud extension of such indexes to the case of multiple\ud confluences are finally proposed

An Approach to Predict Debris Flow Average Velocity

“…The debris flow velocity is mainly dominated grain size, slope angle, sediment concentration, etc. [18][19][20][21][22][23][24]. In this study, we took four variables into consideration using the GSA-RBF.…”

“…It can be seen in Figure 3 that the debris flow alluvial has a great impact on the villages and farmlands. Meanwhile, the alluvial fan also narrows the width of the Jinsha River [21,[42][43][44]. If the river width becomes narrow, the river flow velocity will become fast.…”

“…The debris flow velocity is mainly dominated by the following parameters: grain size, slope angle, sediment concentration, etc. [18][19][20][21][22][23][24]. Armanini et al [18] conducted the laboratory experiments studying the rheological behavior of high-concentration granular-liquid mixtures.…”

“…Iverson et al [20] collected data of 28 controlled experiments to reveal that sediment mud content causes systematic differences in flow dynamics. Stancanelli [21] conducted a set of 19 experiments considering three values of the confluence angle, two slopes of the tributary, and three different triggering conditions. Stancanelli et al [22] considered that within the investigated range of parameters, the slope angle was the parameter that mainly influences the stony debris flow mobility.…”

Computational Fluid Dynamics for Modeling Gravity Currents in the Presence of Oscillatory Ambient Flow

“…Gravity currents are phenomena of great interest in the field of engineering and geophysics with numerous important environmental and industrial applications [1,2]. These include: the outflow of brackish waters [3] referred to as viscous gravity currents, pyroclastic flows [4] referred to as particle-laden gravity currents and mud and debris flows [5,6] referred to as concentrated flows.…”