スナガニ巣穴の力学的安定性の議論へ向けた濡れた粉体層中の横穴構造の強度推定実験

抄録

Empirical forms for the strengths characterizing stability of a horizontal tunnel in wet granular matter are experimentally derived. The motivation of this study comes from the observation of crab burrows on sandy beach. To understand the mechanical constraints for constructing the stable burrow structures, we perform a set of simple experiments with a horizontal tunnel structure made in a wet granular layer. Then, the tunnel is compressed from the top of the layer using a universal testing machine. During the compression, the shrinking tunnel shape is captured by a camera. Using the measured compression force, stroke, and shrinking tunnel images, we define and measure the mechanical strengths of wet granular matter with a horizontal tunnel. By systematically varying the experimental conditions, we obtained the empirical forms for estimating strength values. Using the measured results, we briefly discuss the mechanical conditions of sandy crab burrows.