Evaluation of Soil Characteristics for Engineering Purposes at Selected Locations in Mandli District, Diyala Governorate, Eastern Iraq

Abstract

   The study area is located in a part of Mandli district. Diyala Governorate, eastern Iraq. It represents an important region within urban growth areas that require detailed engineering designs. Therefore, the research evaluates the engineering characteristics to achieve various engineering purposes with their development.. A total of 15 soil samples were collected from distributed locations, in which then Physical, geotechnical, chemical and mineral analysis tests in the laboratory were achieved. Depend on the rates of sieve analyses the soil samples are classified into three classes as low plasticity clay (CL); low plasticity silt (ML) and a transitional (CL–ML) ; moreover the hydrometer test and atterberg limits by using the (USCS) were also be revealed. It is indicated a dominance of fine-grained soils controlling engineering behavior. Dry density and water content are shown contrast in most sites in additional; it reflected the moderate compaction, swelling and soil plasticity states in some sites. Direct shear tests showed the cohesion varying from (0 to 16.94) kN/m² while internal friction angle ranges from (11° to 38°). However, the result shown that it is related with clay silt and sand content, whereas lower values correspond to higher moisture sensitivity and clay mineral dominance. The Unconfined Compressive Strength test manifested that , the soil sites need for treatments in some sites and others in order to be suitable with settlement and compressively. Chemical analysis indicates moderate to very high for (TDS), (EC) while (pH) values ranged from (6.8 to 7.1). Mineralogical analysis showed the dominance of clay minerals such as (illite and chlorite) which governs plasticity, compressibility, and reduced shear resistance. Gypsum; chlorides; sulfates and carbonates content from the chemical analysis revealed their variation given as (0.74% to 6.54%); (2.08% to 5.73%);(20.5% to 47.5%) and (0.34 to 3.05%) respectively. Thus, the chemical properties of soils show their influencing on the engineering behaviors with suitability for building and urban growth after soil treatment in most study area.