Evaluate the clay minerals physicochemical properties on Bonab swelling soils

Document Type : Original Research


Department of Agriculture, University of Mohaghegh Ardabili, Ardabil, Iran


The aim of this study is investigation of the swelling potential of the Bonab city’s soils and created the empirical relations between physicochemical properties of the clayey soils of Bonab with the swelling potential. The studied area is located about 130 km southwest of Tabriz in northwest of Iran. Geologically Bonab is covered by the Quaternary alluvials and recent soils which mostly is fine-grained contains different amounts of clay minerals where causes several events like swelling. In order to assessment of the swelling potential and characteristics of Bonab soils and establish relationships between these properties, the extensive field study especially on the agricultural fields (Bonab is the agricultural-based city), sampling and laboratory tests (classified in physical, chemical and mechanical) are conducted. For the reducing the investigation’s errors, the 20 different location is selected and sampling is taken as representative. The results of laboratory tests are classified based on United States Department of Agriculture (USDA) classification which indicated the most of Bonab soils are clay, clay loam and silty clay with the sandy clay and salt. Also, according to the swelling potential indirect assessment, these soils are located in medium to high swellability.