The role of chemical parameters and soil texture quality in the erosion of adobe in the Belgias historical site

The ruins of impressive structure made by adobe known as the city of “Belgheis” is located 3 km from Esfarayen in the province of North Khorasan of Iran. The role of soil quality in the occurrence of damages to clay and adobe structures of Belqis area is the purpose of this research. Choosing the right soil is the first step in the preparation of adobe, Therefore, it is necessary to study the role of soil. The collected samples were analyzed by using Physical, chemical and mineralogical studies. The fine-grained soil texture is full of sand, silt with reduction of clay. also, the destructive phases of Muscovite and Calcite are in samples. All of These are in accordance with soil studies of the region. these cases as Physical and Chemical was determined as parameters of soil in process of Damage caused by descending humidity.