Solidification/Stabilization of Contaminated Soil in a South Station of the Khurmala Oil Field in Kurdistan Region, Iraq  
[PERSON]  
Civil Engineering Department, College of Engineering, Salahaddin University-Erbil, Erbil 44001, Kurdistan Region, Iraq: [EMAIL_ADDRESS] (A.M.H. ); [EMAIL_ADDRESS] (S.Q.A.) [PERSON]  
Civil Engineering Department, College of Engineering, Salahaddin University-Erbil, Erbil 44001, Kurdistan Region, Iraq: [EMAIL_ADDRESS] (A.M.H. ); [EMAIL_ADDRESS] (S.Q.A.) [PERSON]  
Civil Engineering Department, College of Engineering, Salahaddin University-Erbil, Erbil 44001, Kurdistan Region, Iraq: ahmed. Several researchers, including [PERSON] et al. [11], [PERSON] et al. [12], [PERSON] and [PERSON] [13], [PERSON] et al. [9], and [PERSON] and [PERSON] [14], investigated the geotechnical properties of oil-contaminated soils, indicating decreased soil strength and increased plasticity due to oil contamination. The permeability of soils also decreased significantly. Furthermore, quartz sand completely saturated with engine oil can lead to a substantial reduction in soil friction angles and a dramatic increase in soil volumetric strain [15]. In addition, [PERSON] and [PERSON] [16] reported that the contamination of soil by crude oil had an adverse effect on the base of the pile regarding geotechnical behavior degradation. Moreover, [PERSON] et al. [17] and [PERSON] et al. [18] investigated the impact of the contamination of gas oil on fine and coarse-grained soil's geotechnical properties; a decrease in the MDD and the optimum humidity levels was also observed with the increase in Arterberg's clay and silt limits. Various methods have been used in recent years to remediate crude-oil-polluted soil. The solvent/surfactant soil-washing technique shows that petroleum pollution soils can cause solubility and extract crude oil soil components [1]. Although biosurfactant solutions have a considerable capacity to extract crude oil from polluted soil by washing conditions, the results showed that the washing-temperature efficiency of crude oil removal from contaminated soil was the most significant factor, compared with the least influential factor which was washing time [2]. In turn, the bioremediation of crude oil polluted soil was achieved by isolating strains of the most efficient biodegradable material in the laboratory; this study demonstrates that many aromatic and saturation hydrocarbons with a chemical composition that is similar to that of crude oil were extracted successfully by the strain [19]. With different remediation approaches, the active degradation of crude oil contaminated saline soil can be achieved by using nitrogen additions, the inoculation of arbuscular mycorrhizalas, and the cultivation of Suaeda salsa [20]. In other studies, soil was remediated through pyrolytic treatment. Compared to the reaction time, the pyrolytic efficacy was more affected by the working temperature [21]. Almost all studies in the literature, as mentioned earlier, were focused on agriculture, soil science, and the climate. Hence, it is crucial to analyze these research results for the aim of engineering applications in order to promote practical soil remediation. Thus, oil-contaminated soils must be cured efficiently with methods to enhance the mechanical and geotechnical properties of the soil [22; 23]. Furthermore, the solidification/stabilization method, which is accomplished by incorporating cement [24; 25], lime [26], fly ash [27], as well as other bonding products into a mixture which is used to impale the contaminants in the polluted medium and ensure long-term safety, is the most effective technique. Solidification describes a process that converts contaminated media into a homogenous solid material with strong structural integrity through its encapsulation in order to change its physical properties. Stabilization describes a process that minimizes contaminated soil's hazardous potential by limiting its solubility, mobility, or toxicity. Therefore, satisfactory results can be achieved using this technology.