The soil-soil material forming the structure of the defensive rampart of the settlement of the IX century N. E. in comparison with the background soil has been studied. A horizon related to pre-Holocene soil formation has been identified in the profile of the background soil. Some physico-chemical and geomorphological parameters of the soil material are presented. The process of anthropogenic introduction of carbonates and their further redistribution inside the bulk shaft structure has been revealed. Some construction techniques used in the construction are shown, based on the characteristics of the soil substrate used.