Tensile Strain Measurement Using a Plate Specimen in Cohesive Soil

Abstract

It is important to evaluate tensile strength characteristics of foundation and embankment material of fill dam in order to examine conditions for crack development which is one of the causes for the hydraulic fracturing. While it is possible to evaluate tensile strength of hard rock by fixing both ends of the specimen with chucks and applying the force directly, it is not possible to use the same method for soft material like cohesive soil. In this study, we designed an I-shaped plate specimen by the FEM analysis so that it contains parts where stress acts almost uniformly. The direct tensile test was performed with the specimen made of volcanic ashes loam and the tensile strain was measured by image instrumentation using digital cameras. Our tensile test method enabled continuous measurement of tensile stress and strain with soft material like cohesive soil.