Landslides entail downhill flow of a large amount of mass, typically soil and other granular matter, and constitute a major geological hazard in India and across the Asia-Pacific region. Climate change, deforestation and other anthropogenic activities have greatly escalated the frequency and detrimental impact of these events.

Landsliding is generally accompanied by large rocks – boulders – that are either part of the original collapse or are entrained by the flow. Such boulders are known to be the cause of a significant percentage of the overall damage from these events, because of the much larger momentum per unit volume that they carry. At the same time, boulders – whether entrained or stationary – can affect the downhill flow in important ways.

This motivates the present study of entrainment and transport of boulders by granular flows. In particular, we seek to address the following questions How are stationary boulders entrained by a granular flow?

How do boulders move in a granular flow? And where are they finally deposited?

How is a granular flow affected by entrained boulders? How is the flow’s runout and its spread affected? Can a simple boulder-flow interaction law be formulated?

To answer these questions we need to understand the forces that act between a granular flow and a stationary or entrained boulder. In particular, how are these forces affected by the boulder’s geometry, surface texture, location within the flow, the type of grains in the flow, and the volume and rate of the flow itself.

For this, we will pursue both experiments and theoretical modeling. To begin with we will focus on shallow granular flows and squat cylindrical boulders with circular or elliptical cross-sections. Experiments will be conducted on an inclined flow setup and will involve flow visualizing, force measurement and boulder tracking. Theoretically, we will approach the problem by appropriately extending shallow water theory to granular flows with an internal mobile rigid body.

We envisage important applications of this work, and its extensions, to a variety of fields. Information about boulder momentum and migration will help inform design of arresters used to protect homes and infrastructure against such natural hazards.

At the same time, there is increasing interest in boulder motion on small extraterrestrial bodies – like asteroids – where surface boulder tracks and emplacement offer a window into the geological and dynamical evolution histories of these bodies.

Dr

Edward Hinton

DECRA Senior Research Fellow

School of Mathematics and Statistics

Dr

Edward Hinton

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Faculty of Science

Primary Interest

Applied Mathematics

Dr

Edward Hinton

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