Experimental investigation of mobility and deposition characteristics of dry granular flow

This paper presents an experimental investigation of mobility and deposition characteristics of dry granular flow, by a number of flume tests on silica sand no. 3 and silica sand no. 7, to interpret the effects of angle of slope, granular volume, cushion, granular structure, and granular size on the mobility and deposition characteristics of granular flow. Along a given slope, an increase of the amount of sand impaired its mobility. However, for a given amount of sand along a slope, an increase of the angle of slope resulted in a V-shaped change of the angle of mass center movement, implying the existence of a characteristic combination of the angle of slope and the amount of sand to yield the maximum mobility of granular flow. The angle of mass center movement increased while increasing the thickness of cushion, showing that the cushion impaired the mobility of granular flow. Granular structure using the mixed structures of silica sand no. 3 and silica sand no. 7 affected greatly the mobility of granular flow, by showing an inverted structure in the near runout area with the deposition of the materials in the upper half of original grading structure in the far runout area for the inverse grading structure and normal grading structure. The mobility of granular flow increased with the change in turn of the inverse grading structure, the uniform structure, and the normal grading structure. The increase of the grain sizes of granular material enhanced its mobility. In addition, the angle of mass center movement showed a more reliable assessment for the mobility of granular flow in comparison with the angle of maximum mass movement.