Geotechnics or soil mechanics is one of subfields of civil engineering which studies the behavior of soil under pressure from various structures. Two basic sciences for studying the behavior of soil and stone (i.e. soil mechanics and stone mechanics) are employed in geotechnical engineering. Among areas of research for soil engineers in this faculty one can mention the bearing capacity of soil under foundation, the consistency of slopes and excavation, man-made soil structures (e.g. earth dam), technologies to increase load-bearing of the soil (e.g. pinning and nailing), and using geo-synthetic materials.