Triaxial Tensile Strength Measurement of Compacted Clayey Soils

Abstract

Abstract Tensile strength is strongly related to tensile cracking and is a key parameter required in the rational design of earth structures made of compacted clayey soils, such as earth dams, slopes, and embankments. Experimental studies related to the tensile strength of compacted soils that consider the influence of confining pressure is rather limited in the literature. For this reason, a novel experimental technique is developed for the measurement of triaxial tensile strength. Statically compacted soil specimens with a reduced central section are fabricated using a specially designed mold at different initial moisture contents but at the same dry density. The reduced triaxial extension stress path is followed during the test, which induces tensile failure on the reduced central section of the specimen. The triaxial tensile strength increases with an increase in initial matric suction (or decrease in initial degree of saturation) for the investigated range in this study. The variation of triaxial tensile strength with the confining pressure shows a non-monotonic variation, which is attributed to the volumetric deformation prior to failure and the failure mode transition. The test results provide clear evidence of the nonlinearity of the failure criterion, especially when the soil is subjected to tension.