Samer Sadek

Consolidation and Permeability of Transparent Amorphous Silica

The consolidation and permeability of transparent amorphous silica are studied in this paper. Transparency is achieved by matching the refractive indices of the amorphous silica particles and the pore fluid. The fundamental premise of this research is that transparent synthetic soils made of amorphous silica can be used in model tests to study three-dimensional deformation and flow problems, using nonintrusive optical visualization techniques, if amorphous silica can be produced with geotechnical properties similar to natural soils. The amorphous silicas studied in this paper exhibit consolidation behavior similar to that of organic clays and peat. The permeability of the material falls within the range typically reported for clays and peats.

Optical Measurement of Strain and Stress

A review of optical techniques that can be used for measurement of deformations and stresses in transparent synthetic soils is presented in this chapter. The presented techniques include methods based on (1) target tracking and image cross correlation, (2) speckle and holographic interferometry, (3) photoelasticity, and (4) cross tomography. All techniques are presented with a brief background for basic understanding of the major experimental issues, as well as a discussion of how they can be applied for measuring stress and strain in transparent soils. The advantages and disadvantages of using each technique are also discussed.

Application of DIC for Measuring Deformations in Transparent Soils

This chapter proposes a simple optical technique for measuring spatial deformations in transparent synthetic soil models using digital image correlation (DIC). The accuracy of the DIC technique was evaluated based on a scheme of predefined digital movements of synthetic soil images. Finally, a model consisting of a strip footing on a synthetic transparent soil is presented. The spatial deformations in the model are evaluated using the proposed DIC methodology and compared to the result of finite element analysis.