Measurement of mechanical properties at the bottom of a granular pack by wavelength-scanning interferometry

Granular materials are conglomerations of discrete macroscopic particles. These deceptively simple materials, however, are very different from the ordinary solids, liquids and gases we know from physics textbooks. One method to understand the static mechanical properties of granular media is to study the contact forces and displacements particle by particle, and generalize the statistical results for the whole pack theoretically and experimentally. Unfortunately, there are a range of interpretations and little experimental data to compare to and subsequently we have made relatively little progress in understanding force transmission in granular media since the 1960s. Progress requires experimental methods that are accurate down to the single particle level. In this thesis, we introduce a new reflective scanning-wavelength Fizeau interferometer which achieves this and has the advantages of a wide range and is applicable to three dimensional systems. [Continues.]