This research investigates the suitability of fuel oil in improving gypseous soil. A detailed laboratory tests were carried-out on two soils (soil I with 51.6% gypsum content, and soil II with 26.55%), where the two soils were obtained from Al-Therthar site (Al-Anbar Province-Iraq). This study examines the improvement of soil properties using the gypsum material is locally available and low cost to minimize the effect of moisture on these soils by using the fuel oil. Study was conducted on two models of the soil gypsum, from the Tharthar area. The first model was sandy and slimy contents of Gypsym (51.6%) and the second is clayey soil and the content of Gypsym is (26.55%). The program included tests measuring the permeability of soil and compressibility and their collapse properties. Have been found bearing shear strength of the soil and the amount of weight loss of fuel oil and the recession in the soil as a result of drying temperature (50oC) in addition to testing category. These tests have been conducted on the treated soil and untreated to observe the effect of soil treatment on the engineering properties when mixed with varying degrees of fuel oil with the equivalent of the water content. The results showed that fuel oil is a good article to modify the soil gypsum, in order to have improved the basic properties of the soil gypsum of collapsibility and permeability, which is one of the fundamental problems of the soil gypsum and retained soil by an appropriate amount of the durability of storytelling gives durable and bearing capacity for the soil enough to carry the weight of construction and access to sustainability of these soils are suitable for use is permitted in areas exposed to moisture.

Keywords: Geotechnical Engineering; Gypseous soil; Enhancement of Gypseous Soils