Correlating Standard Penetration Test (SPT) with Various Soil Properties in Different Kirkuk City Locations: A Case Study Utilizing Inverse Distance Weighted (IDW) for Assessment and Prediction

Department of civil Engineering, University of Kirkuk, Kirkuk, Iraq

^a* Corresponding author m.o.ibrahim@uokirkuk.edu.iq
^b aram_raheem@uokirkuk.edu.iq
^c ibrahim.j.naser@uokirkuk.edu.iq
^d naj7engg@uokirkuk.edu.iq
^e encm22008@uokirkuk.edu.iq

Abstract

Due to cost limitations, it is not practicable to experimentally investigate the soil characteristics over the entire city. Given this, the study has focused on using a geographic information system, especially the IDW technique, with linear regression models. The study's data collection was taken from different locations around Kirkuk province. The IDW technique was used to examine the Standard Penetration Testing (SPT) and chemical properties such as total Sulphur content SO₃ (%), total soluble salt TSS (%), organic content ORG (%), chlorine concentration Cl (ppm), free calcium carbonate content CaCO₃ (%), Gypsum content GYP (%), and pH. Both single-regression and multi-regression models were utilized to interpolate the SPT and soil properties. Sets of digital maps were created to examine the chemical properties and SPT of Kirkuk soils. SPT values can be predicted more precisely based on integrated physical and chemical soil properties rather than chemical or physical characteristics alone. SPT and physical soil components have been shown to have various positive and negative relationships. While the SPT values have shown favorable relationships with both silt and clay amounts, they have shown negative correlations with gravel and sand contents. The variations of SPT with chemical soil properties have revealed positive correlations with SO₃ (%), TSS (%), CaCO₃ (%), GYP (%), and pH contents, while negative correlations were obtained between SPT with ORG (%) and Cl (ppm).