Numerical modeling was used for study of stress-strain state (SSS) of 100 m high rockfill dam seepage control concrete face for a number of alternatives of rockfill deformation and arrangement of an under-face zone. Values of rockfill linear deformation modulus varied from 60 to 480 МPа, and of Poisson’s number they were from 0 to 0.3. The alternatives were considered where the face rested directly on the under-face zone of crushed stone or on concrete bedding. In the last case consideration was made of decrease of shear characteristics in the contact between the face and concrete bedding by arrangement of a bitumen mastic layer. As a result of study there was investigated the role of tangent stresses on the contact of the face with the under-face zone in formation of the concrete face SSS. It was revealed that tangent stresses cause longitudinal forces in the face as well as longitudinal bending. It was shown that presence of bituminous lubrication layer permitted decrease by one third of tangent stresses at the contact and tensile stresses in the face.