Suction Stress Influence on Earth Retaining Structures

A series of shear strength tests were performed on six different types of fine grain soils at controlled densities and degrees of saturation. Since these variables were controlled the most important variable affecting the shear strength of the soil is the change in the degree of saturation producing a change in the suction stress. These changes in suction stress modify the state of effective stress, thus affecting soil behavior. These results were used to compare the variation in factors of safety for cantilever, gravity, and tie-back wall designs produced by the change in effective stress due to saturation, for short term condition. In addition, a desired safety factor was chosen and the influence in the final design due to changes in saturation was investigated, and was complemented with cost estimations. The final results have demonstrated a suction stress influence on the wall design, and cost, when short term conditions are considered.