Gypsiferous soils are soils that contain sufficient quantities of gypsum which can be considered as problematic materials due to the collapsible nature of gypsum with the presence of water. The behavior of gypsiferous soils when exposed to water is largely dependent on the amount and type of gypsum within the soil. Remarkable evidences are available on failures in dams, highways and some other structures constructed above gypsiferous soils or rocks. Garmiyan district is located in the southern part of Sulaymaniyah Province,The administrative center of the district is Kalar City where major infrastructural projects are under construction. The region has semi-arid climate with annual rainfall of 326 mm and temperatures varies between 5 to 38 C0 in winter and summer respectively. The results show The direct shear test for samples with their natural gypsum content shows that the friction angle varies from 15° 𝑡𝑜 35° and cohesion values varies from 13.2 𝑡𝑜 27.6 𝑘𝑁∕𝑚^2 . Increase of gypsum content, up to 20%, cause 50% increases in the values of friction angle, while this increase causes 30% decrease in cohesion.
