Suction stress influence on strength parameters used in geotechnical engineering

A series of shear strength tests using identical specimens but at different degrees of saturation were performed. Since the specimens were identical the most important variable affecting the shear strength and undrained strength parameters is the change in suction stress that modifies the state of effective stress, thus affecting soil behavior. Laboratory results demonstrated that this change in degrees of saturation has an effect on certain types of soil that can be significant for design. Three types of geotechnical engineering projects were analyzed: spread footing design, earth retaining structures design, and slope stability analysis. Changes in dimensions and safety factors of shallow foundation can be seen from a change in suction stress. Earth retaining structures performance and slope stability was also analyzed for the changes observed. Finally, a comparison between safety factors and its relationship to uncertainty in geotechnical engineering design at different degrees of saturation was performed.