The study consists of two stages: the first one is to improve the gypsum soil with cement or calcium chloride and the second stage is to expose these soil specimens to series of wetting and drying cycles .Three soil specimens were taken and marked as (A,B and C) with gypsum content (47, 32 and 23)% respectively .The results show that cement additive increases the cohesion of soil specimens to 50% and collapse potential decreases with 65% and soil specimens improved with calcium chloride increase the cohesion up to more than 70% and collapse potential decreased about 70%. In the first cycle for wetting and drying cycles for soil specimens improved with cement the cohesion decreases about 25% and stays with the same ratio of the decreasing along the other cycle up to twelfth cycle. Collapse potential remains with the same value and is not affected by cycling of wetting and drying. In the first cycle for soil specimens treated with calcium chloride there is no effect in the first cycle whereas in the fourth cycle the cohesion increased by 60% and in the eighth cycle the cohesion decreased 8% and remains stable until the twelfth cycle. Collapse potential increases from one cycle to another by (30-50) % for all soil specimens.

Gypseous soils are problematic soils that cause large deformations in the constructions that are built on it. Therefore, many binders have been used to reduce this impact. Traditional soil binders like lime or cement have environmental problems in terms of sustainability. Thus, sustainable substances have attracted appreciable interest in recently soil enhancement. Biomaterials are being developed to enhance geotechnical engineering properties like hydraulic conductivity, strength, and slope stability of varied soil types. This study aims at evaluating the engineering characteristics of gypseous soil treated with xanthan gum biopolymer. The tests performed on three types of gypseous soil with various gypsum contents and different properties. Gypseous soils were mixed with various contents of xanthan gum with a percentage of 2, 4, and 6. The compaction results indicated that xanthan gum decreases the maximum dry density and increases the optimum moisture content. The treated gypseous soils exhibited a low collapse potential by more than 30% - 45% with xanthan gum. The direct shear results of biopolymer treated soils showed significant shear strength gains. The results of the current study imply xanthan gum biopolymer improvement as an environmentally friendly method to improve the engineering properties of gypseous soil.

Using remote sensing data and Geographical Information System (GIS) methods, this study tries to anticipate the optimal urban expansion areas in Erbil city. The Analytical Hierarchy Process (AHP) concept was used to create a map of urban expansion. Several social, economic, environmental, utility and physical characteristics including land cover, roads, slope, aspect, elevation, soil texture, power lines, water and exclusion, were combined to construct a final land suitability index map. ASTER Digital Elevation Model (DEM) was also followed to derive slope and aspect variables. While organic growth is prominent, considerable growth is expected to occur around the outskirts of current settlements. This research highlights the use of modelbased prediction of urban sprawl in the development of the city’s master plan and road network plan. The findings of this study can help planners and policymakers adopt preventative or regulating measures in advance and make better informed strategic decisions.

There are vertical slopes on the western banks of Tigris near Al-Alam Bridge in Tikrit, Iraq. These slopes are not supported and are located near an important road at Tikrit University. This study aims to find a safety factor (FOS) of the slope to prevent failure, besides its effect on human and financial losses. The study consists of two parts: the first part studied the layers of the slope and found the soil resistance coefficients. The second part analyzed the stability of the natural slope itself under the impact of the water level change of the Tigris River and the external loading. The analysis was done by a program called (PLAXIS 3D), which depends on the finite element method. The finite element method is a numerical approach that searches for approximate solutions and solves problems by dividing the problem into several triangular elements linked to each other by points called (nodes). The results showed that the vertical slope stability at the natural state with no influences indicated was in a semi-stable state with a factor of safety equal to (1.04865). The factor of safety decreased by (0.423%) with rising the river level until it reached (1.04074) at (93 m a.s.l.[1]). As for the applied external loads condition, the factor of safety for imposed (50,150 and 250 kN/m2) decreased by (4.738%), then the soil body failed when the factor of safety was (0.9902). In the critical state, the soil body failure at this stage and the factor of safety became equal to (0.98769) with decreasing by (5.812%).

Gypsum reinforcement in dry soil provides activity resistance. It quickly becomes a source of danger in the conditions of partial and complete soaking of gypsum soil as a result of the dissolution of gypsum, which poses a great danger to the structures built on this soil. The danger increases when water flows through it and works to leach the soil, which leads to the loss of its mass by leaching gypsum. The soil is chemically and mechanically improved to enhance its geotechnical properties, but despite its great advantages in strengthening, it has significant negative effects on the ecosystem, so the use of environmentally friendly materials is essential. Pectin was selected as an improved biopolymer and added at three different contents (0.5, 1, and 2)% to create a soil mixture and at four different gypsum contents (10, 20, 40, and 62%) to evaluate the chemical and mechanical properties of the improved mixture. Develop an engineering model to leach the soil and pectin mixture. The results showed a significant decrease in CH and CP. values due to biogel encapsulation of soil particles and pore filling properties. The percentage decrease in the values of (CH) reaches (0.67, 73, 75, and 68%) for soils 1, 2, 3, and 4, respectively. After soil (1, 2, 3, and 4), CP values decreased in percent (0.63, 0.63, 0.65, and 0.7%). TDS decreased at a biopolymer content of 2% from 1050, 1200, 2200, and 2500 mg/ml to 320, 540, 468, and 570 mg/ml of soils 1, 2, 3, and 4, respectively.