Geotechnics is a searching science that introduces mechanical behavior of geology and its function to engineers. Geotechnics engineering is a branch of civil engineering that it s goal is natural materials study existing in upper layer of the earth. Generally, this science includes application of soil mechanics and rock mechanics in foundation design problems. Soil mechanics is a branch of engineering sciences that studies physical-chemical characteristics and soil behavior under received loadings. Foundation engineering is application of soil mechanics principles in scientific problems.