Mapping Geotechnical Soil Properties of Ranya City in Kurdistan Region of Iraq Using GIS

Geotechnical map is a vital guidance to visualize the behavior of soils. The objective of this paper is to present the geotechnical maps that can be used for preliminary investigation in Ranya city of northern Iraq. The study area is 13.02 km2 with latitude and longitude of 36°15'14" N 44°52'59" E, respectively. A total number of 116 boreholes with the depth up to 5.0 m were utilized to create allowable bearing capacity, particle size, and Atterberg limit maps. Kriging interpolation tool in the ArcGIS software was used to analyze the soil properties data and to achieve the maps. The appraisal study area was divided into three layers 0.5-1.5, 1.5-3.0, and 3.0-5.0 m and the results show the average bearing capacity of 112.2, 168.5, and 244.2 kN/m2 sequentially. Moreover, Particle size distribution’s results illustrate that gravel percentage increases in the deeper layers, while fines content decreases with no significant change of sand content. In addition, very high bearing capacity areas were mostly found in the southern and northern parts of the studied area. However, the eastern area represents the area with the minimum bearing capacity where it gradually increases toward the west. Furthermore, the liquid limit and plasticity index reduce from the north to south with an increase in depth of the layers from 3.0-5.0 m. The highest liquid limit value is observed in the depth of 1.5-3.0 m.