Comparative assessment of investigation methods for tensile strength of soils: A review

Soil tensile strength is often overlooked due to its low magnitude. This review compares testing methods, classifying them as indirect and direct. Indirect methods are simple but rely on unrealistic assumptions, causing inaccuracies and preventing stress-strain curve acquisition. Direct methods obtain the full stress-strain relationship and are divided into triaxial and uniaxial tensile tests. Triaxial tensile tests involve complex failure and end effects, making uniaxial tensile tests preferable. Based on force direction, direct tests are categorized as vertical or horizontal. Vertical uniaxial tensile tests is influenced by soil self-weight, whereas horizontal uniaxial tensile tests offers clear advantages. For specimen fixation, clamping is more efficient and reliable than adhesive, anchorage, or frictional methods. Proposed improvements include using pulleys to reduce base friction, designing dumbbell-shaped molds for effective clamping, extending the tensile section, and scaling up molds for wide-graded soils.