Measurement of tensile strength of unsaturated sandy loam soil

This paper presents a method of measuring tensile strength directly on laboratory prepared soil samples. The soil used in the tests was a St. Benoit sandy loam (Bt) from the Macdonald Campus Research Station, Ste Anne de Bellevue, Que., Canada. The three experiments were: (1) measurements of tensile strength of soil samples at different moisture contents, prepared making an effort to keep constant soil density; (2) measurements of tensile strength of soil samples at different bulk densities, prepared making an effort to keep constant moisture content; and (3) measurements of tensile strength of soil samples at different moisture contents, prepared using soil at different moisture content at the time of compacting and using the same compaction force. It was concluded that drying the soil after densification can improve soil strength. However, reducing the water content before densification led to decreasing soil strength, or a higher requirement for compressive energy to achieve the same tensile strength. Densification always increased soil strength independent of the compaction path.