Experimental evaluation of the effects of pull rate on the tensile behavior of a clay

Tensile strength is one of the main variables involved in the formation of desiccation fractures in clay. It is known that the drying rate affects the final amount of cracks in a soil, which points out to the potential influence of rate effects in soil cracking. The effects might be related to variations in the tensile strength affected by different shrinkage rates. A limited amount of investigations have looked at the impact of strain rate on the tensile strength of soil. This study examines the combined effects of pull rates and high water contents on the tensile strength of a clay. Particle Image Velocimetry analysis was also carried out on pictures taken during the tests to examine the strains generated. It was found that the effect of pull rate on the tensile strength of the clay was negligible compared to the effect of the water content. Pull rate did affect the stiffness response of the soil. The findings revealed that the influence of the evaporation rate on soil fracturing might be related more to the rate dependency of the stiffness rather than to significant changes in tensile strength.