Abstract
Soil is considered an essential component of the factors that are affecting the structures. Due to the problems that are faced under various conditions while the structure is in use, the behavior of the soil is complex. The presence of cavities inside various types of soil, such as gypsum soil and the soil of some old towns, is one of its difficult problems. The formation of these cavities is due to natural and industrial causes, one of the natural causes being the dissolve of salts inside them. As for the industrial one, it is due to the presence of some old buildings. The presence of this type of cavities affects the life of the structures and as a result, it creates cracks in the foundation, therefore reducing the life of the structures.
The unexpected formation of cavities inside the soil was based mainly on some practical experiments for this research. Two cavities have been created inside the soil with different locations from the anchor to study the capacity of the anchor. The results showed that the presence of the cavity affects the capacity of the anchor according to its location from the plate as well as from the rod. The closer the cavity are to the plate; the capacity have been decreased by a certain percentage depending on the distance from the plate anchor.