Experimental investigation of dry granular flow impact via both normal and tangential force measurements

Abstract

The study of granular flow is important for natural hazards such as avalanche and debris flow. In this context, granular flow impact against a retaining wall was investigated through the measurement of both normal and tangential sub-forces. The tangential sub-forces change from positive to negative with respect to the wall in the impact process, which can be classified into two impact states according to the development of the stagnant zone. In the process, interface friction between the granular material and the wall is calculated according to normal and tangential forces and defined as the equivalent interface friction angle, which is observed to vary, and is smaller than the value measured in interface friction tests. The absolute value of the equivalent interface friction angle decreases with slope angle. It was also observed that a reduction in the interface friction angle of the wall has a negligible influence on the impact force calculation, while a reduction in the interface friction angle of the flume base leads to a significant overestimation of the force. These findings should significantly aid the study of granular flow and its applications.

Debris flow impact estimation on a rigid barrier

“…Lately Jiang and Zhao (2015) proposed a new formulation for impact force estimation, introducing the influence of the tangential forces during the impact due to the friction between flow and wall. Combining the data obtained using the surface pressure gauge and flow characteristics (depositional height and velocity), we propose the following equation to estimate impact force on a rigid wall:…”

Role of baffle shape on debris flow impact in step-pool channel: an SPH study

“…(2) Fluid-solid body collision model considering both normal and tangential forces between flows and walls Jiang and Zhao (2015) and drag forces Vagnon and Segalini (2016); (3) shock wave collision model based on the shock wave speed inside a debris flow Wei (1996); Eglit et al (2007). Usually, the last two models require particular input parameters such as the stiffness and strength of the impacting bodies and the shock wave speed.…”

Reply to Anonimous Referee #1

“…Lately Jiang and Zhao (2015) proposed a new formulation for impact force estimation, introducing the influence of the tangential forces during the impact due to the friction between flow and wall.…”