Distributed water pressure force. This distributed term is translated into equivalent nodal force terms on the edges of elements. The distributed force is automatically calculated as density_water g where is the gravitational acceleration, and is the distance from the phreatic level. In a 3d calculation, the water pressure force acts in the direction dir_x dir_y dir_z. In a 2d calculation, the water pressure force acts in the direction dir_x dir_y (and dir_z should not be specified).
Also the record groundflow_phreaticlevel and force_element_edge_water_geometry should be specified.