Investigation and comparison of physical properties of marl soils in Qom Lake basin with two different maternal formations

Erodibility, resistance and soil engineering behavior are affected by their physical and chemical properties. Lithology and characteristics of parent rock can be such factors that influence on soil properties and behavior. The aim of this study was to investigate and compare some of the physical properties of Marly fine grained soils with two different maternal formations in a unit basin (Qom salt lake). The study was carried out on 61 soil samples. The physical parameters studied are the specific weight of the unit volume of soil, the grain size, the Atterberg limits and the soil activity number, which was measured according to ASTM standards. The investigation of the above mentioned soil properties showed that the soils of these two marl formations are silty and all are classified in the category of fine-grained soils with low to moderate plasticity. The values of the soil activity number and the Atterberg limits, especially the plasticity limit and plasticity index, indicated that the clay minerals in these soils are more Kaolinite and Illite and less montmorillonite. The comparison of variance and mean of physical properties of two groups of soil by using t-student (two independent groups) test, showed that in most of the physical properties of two Marl Soil groups consist of liquid limit, plasticity index, soil activity number and percentage of clay, silt and sand, there is a differences significant level of confidence of over 95%. This difference of physical properties was validated by clustering the samples by hierarchical method. Considering to the unit basin and similar conditions in the formation and evolution of these two groups of soil, the results of this study indicate that conditions and characteristics of the sedimentary environment of the matter rocks mainly affected on the properties and behavior of soils, especially in their early stages of evolution.