Shear strength behavior of highly expansive soil

This study investigates the effect of loading path on the drained shear strength of Al-Qatif expansive clay obtained from the northeast region of Saudi Arabia. Testing was performed on statically compacted samples using strain controlled direct shear tests. Two loading paths simulating different field conditions were considered. First load path involved the inundation of test samples under target normal stress then shearing. Second load path involved inundation of test samples under low normal stress (10 kPa) followed by incremental increase in normal stress to target value before shearing. Results of the tests indicate that proposed loading path has an insignificant effect on the drained shear strength of tested samples. In addition, a unique relationship exists between drained shear strength and final water content for both load paths.