The Use of Void Ratio (e) in Earth Dams: Agenda

Introduction (speaker, audience, purpose of webinar) (10 min)
- Why is void ratio important in Earth Dams
- Closely related to relative density and unit weight
Review of phase relations in soil mechanics (10 min)
- Void ratio, porosity, water content, degree of Saturation
- Dry and Saturated 2-phase diagrams
- Density, unit weight, dry unit weight
Void ratio is not a measured in lab/field, it is calculated (5 min)
In sands we can obtain the minimum and maximum void ratios (emin, emax) (5 min)
Earthen dam cross-sections, different soils (5 min)
What are the ranges of void ratio in different soils (5 min)
Q/A Period 1 (10 min)
How does e relate to more complex soil parameters (10 min)
- Volumetric strain
- Consolidation
- Shear strength
Deformation in dams is assessed by changes in void ratio (5 min)
Primer on compression & consolidation theory (5 min)
Engineering consequence - settlement of dam crest (5 min)
Stability in dams is assessed by examining the available shear strength (5 min)
Primer on shear strength (5 min)
Engineering consequence - slope or foundation stability (5 min)
Advanced interpretation of void ratio (10 min)
- Critical void ratio
- What occurs at a critical void ratio and effective stress
- Approaching steady state
- Static Liquefaction
Q/A Period 2 (10 min)