Behavior of Compacted Soil in Tension

An analysis of cracking of clay cores of earth dams requires an understanding of behavior of soils in tension. A study of a typical core material is performed to investigate the various factors influencing the tensile strength and stress-strain relationships in tension. Studied are effects of water content, compactive effort, rate of loading, and change of plasticity by adding bentonite. Various experimental procedures for tensile tests are examined with the indirect tensile test chosen as the most convenient. The experimental technique used with this type of test is described in detail. The test results indicate that the tensile strength of a typical low to medium plasticity core soil can be assumed to be zero for practical purposes of design and analysis. The stress-strain properties are, however, needed if attempts in design are made to minimize the cracking potential of an earth dam and if lateral extensometer readings are to be interpreted.