Abstract ID: 3.12325 | Accepted as Talk | Talk/Oral | TBA | TBA

Geohazards such as landslides, rockfalls, and debris flows have become quite prevalent in the geo-dynamically active Himalayan region, which accounts for nearly 76% of the landslide-prone area of the Indian subcontinent. These catastrophic events result in severe casualties and economic losses, often causing extensive structural failures. Characterized by the rapid downhill movement of granular materials, these high-energy flows generally occur due to the complex undulating terrain, necessitating effective mitigation strategies to be designed in the flow path. Conventional countermeasures based on classical earth pressure theories often overlook the dynamic nature of granular flow and impact forces on protective structures. Although existing literature sheds some light on this aspect, the effect of particle morphology – irregular realistic particle shapes with topographic undulations – rugged mountainous terrain on granular kinematics and flow-barrier interactions remains largely unexplored.
The present research employs a 3D Discrete Element Method (DEM)-based micromechanical framework to systematically examine the impact of dry granular flow on realistic mountainous terrain, incorporating two types of mitigation structures: rigid barriers and slit dams. Analysis of granular flow within complex, uneven terrain reveals intricate flow behaviours, such as turning and coalescence, which more accurately replicate real hazard scenarios, while idealistic inclined channelized flows are used for benchmarking the study. Using Wadell’s true sphericity as a measure of particle morphology, the study reveals that with a decrease in the sphericity of particles, flow resistance increases, leading to a reduction in flow velocity. Also, the peak of kinetic energy has been observed to be delayed and attenuated with increasing flow resistance. Similar trends have been observed with force-chain analysis (micro-response), highlighting how contact force distributions influence the total impact force (macro-response) that will eventually govern the design strategy of mitigation structures. The findings provide critical insights into how particulate behaviour at the microscale affects large-scale impact dynamics of granular mass flows. By bridging this gap, the study contributes to optimizing the design and placement of mitigation structures, enhancing their ability to dissipate impact energy and improve the overall resilience of the human commune against geophysical mass flows.